* [PATCH 12/24] x86-64: Use _CET_NOTRACK in memcpy-ssse3-back.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-06-13 15:32 ` [PATCH 05/24] x86: Add _CET_ENDBR to functions in dl-tlsdesc.S H.J. Lu
` (23 subsequent siblings)
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
* sysdeps/x86_64/multiarch/memcpy-ssse3-back.S
(BRANCH_TO_JMPTBL_ENTRY): Add _CET_NOTRACK before indirect jump
to jump table.
(MEMCPY): Likewise.
---
sysdeps/x86_64/multiarch/memcpy-ssse3-back.S | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/sysdeps/x86_64/multiarch/memcpy-ssse3-back.S b/sysdeps/x86_64/multiarch/memcpy-ssse3-back.S
index 7e37035487..3cd1123326 100644
--- a/sysdeps/x86_64/multiarch/memcpy-ssse3-back.S
+++ b/sysdeps/x86_64/multiarch/memcpy-ssse3-back.S
@@ -39,7 +39,7 @@
lea TABLE(%rip), %r11; \
movslq (%r11, INDEX, SCALE), INDEX; \
lea (%r11, INDEX), INDEX; \
- jmp *INDEX; \
+ _CET_NOTRACK jmp *INDEX; \
ud2
.section .text.ssse3,"ax",@progbits
@@ -125,7 +125,7 @@ L(144bytesormore):
sub $0x80, %rdx
movslq (%r11, %r9, 4), %r9
add %r11, %r9
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
.p2align 4
@@ -155,7 +155,7 @@ L(copy_backward):
sub $0x80, %rdx
movslq (%r11, %r9, 4), %r9
add %r11, %r9
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
.p2align 4
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* [PATCH 05/24] x86: Add _CET_ENDBR to functions in dl-tlsdesc.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
2018-06-13 15:32 ` [PATCH 12/24] x86-64: Use _CET_NOTRACK in memcpy-ssse3-back.S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-07-06 14:50 ` Carlos O'Donell
2018-06-13 15:32 ` [PATCH 15/24] i386: Use _CET_NOTRACK in i686/memcmp.S H.J. Lu
` (22 subsequent siblings)
24 siblings, 1 reply; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
Add _CET_ENDBR to functions in dl-tlsdesc.S, which are called indirectly,
to support IBT.
Tested on i686 and x86-64.
* sysdeps/i386/dl-tlsdesc.S (_dl_tlsdesc_return): Add
_CET_ENDBR.
(_dl_tlsdesc_undefweak): Likewise.
(_dl_tlsdesc_dynamic): Likewise.
(_dl_tlsdesc_resolve_abs_plus_addend): Likewise.
(_dl_tlsdesc_resolve_rel): Likewise.
(_dl_tlsdesc_resolve_rela): Likewise.
(_dl_tlsdesc_resolve_hold): Likewise.
* sysdeps/x86_64/dl-tlsdesc.S (_dl_tlsdesc_return): Likewise.
(_dl_tlsdesc_undefweak): Likewise.
(_dl_tlsdesc_dynamic): Likewise.
(_dl_tlsdesc_resolve_rela): Likewise.
(_dl_tlsdesc_resolve_hold): Likewise.
---
sysdeps/i386/dl-tlsdesc.S | 7 +++++++
sysdeps/x86_64/dl-tlsdesc.S | 5 +++++
2 files changed, 12 insertions(+)
diff --git a/sysdeps/i386/dl-tlsdesc.S b/sysdeps/i386/dl-tlsdesc.S
index 2c4764d1aa..128f0af318 100644
--- a/sysdeps/i386/dl-tlsdesc.S
+++ b/sysdeps/i386/dl-tlsdesc.S
@@ -37,6 +37,7 @@
cfi_startproc
.align 16
_dl_tlsdesc_return:
+ _CET_ENDBR
movl 4(%eax), %eax
ret
cfi_endproc
@@ -58,6 +59,7 @@ _dl_tlsdesc_return:
cfi_startproc
.align 16
_dl_tlsdesc_undefweak:
+ _CET_ENDBR
movl 4(%eax), %eax
subl %gs:0, %eax
ret
@@ -99,6 +101,7 @@ _dl_tlsdesc_dynamic (struct tlsdesc *tdp)
cfi_startproc
.align 16
_dl_tlsdesc_dynamic:
+ _CET_ENDBR
/* Like all TLS resolvers, preserve call-clobbered registers.
We need two scratch regs anyway. */
subl $28, %esp
@@ -154,6 +157,7 @@ _dl_tlsdesc_dynamic:
.align 16
_dl_tlsdesc_resolve_abs_plus_addend:
0:
+ _CET_ENDBR
pushl %eax
cfi_adjust_cfa_offset (4)
pushl %ecx
@@ -192,6 +196,7 @@ _dl_tlsdesc_resolve_abs_plus_addend:
.align 16
_dl_tlsdesc_resolve_rel:
0:
+ _CET_ENDBR
pushl %eax
cfi_adjust_cfa_offset (4)
pushl %ecx
@@ -230,6 +235,7 @@ _dl_tlsdesc_resolve_rel:
.align 16
_dl_tlsdesc_resolve_rela:
0:
+ _CET_ENDBR
pushl %eax
cfi_adjust_cfa_offset (4)
pushl %ecx
@@ -268,6 +274,7 @@ _dl_tlsdesc_resolve_rela:
.align 16
_dl_tlsdesc_resolve_hold:
0:
+ _CET_ENDBR
pushl %eax
cfi_adjust_cfa_offset (4)
pushl %ecx
diff --git a/sysdeps/x86_64/dl-tlsdesc.S b/sysdeps/x86_64/dl-tlsdesc.S
index 437bd8cde7..80d771cd88 100644
--- a/sysdeps/x86_64/dl-tlsdesc.S
+++ b/sysdeps/x86_64/dl-tlsdesc.S
@@ -37,6 +37,7 @@
cfi_startproc
.align 16
_dl_tlsdesc_return:
+ _CET_ENDBR
movq 8(%rax), %rax
ret
cfi_endproc
@@ -58,6 +59,7 @@ _dl_tlsdesc_return:
cfi_startproc
.align 16
_dl_tlsdesc_undefweak:
+ _CET_ENDBR
movq 8(%rax), %rax
subq %fs:0, %rax
ret
@@ -96,6 +98,7 @@ _dl_tlsdesc_dynamic (register struct tlsdesc *tdp asm ("%rax"))
cfi_startproc
.align 16
_dl_tlsdesc_dynamic:
+ _CET_ENDBR
/* Preserve call-clobbered registers that we modify.
We need two scratch regs anyway. */
movq %rsi, -16(%rsp)
@@ -166,6 +169,7 @@ _dl_tlsdesc_dynamic:
.align 16
/* The PLT entry will have pushed the link_map pointer. */
_dl_tlsdesc_resolve_rela:
+ _CET_ENDBR
cfi_adjust_cfa_offset (8)
/* Save all call-clobbered registers. Add 8 bytes for push in
the PLT entry to align the stack. */
@@ -216,6 +220,7 @@ _dl_tlsdesc_resolve_rela:
.align 16
_dl_tlsdesc_resolve_hold:
0:
+ _CET_ENDBR
/* Save all call-clobbered registers. */
subq $72, %rsp
cfi_adjust_cfa_offset (72)
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* Re: [PATCH 05/24] x86: Add _CET_ENDBR to functions in dl-tlsdesc.S
2018-06-13 15:32 ` [PATCH 05/24] x86: Add _CET_ENDBR to functions in dl-tlsdesc.S H.J. Lu
@ 2018-07-06 14:50 ` Carlos O'Donell
0 siblings, 0 replies; 54+ messages in thread
From: Carlos O'Donell @ 2018-07-06 14:50 UTC (permalink / raw)
To: H.J. Lu, libc-alpha
On 06/13/2018 11:31 AM, H.J. Lu wrote:
> Add _CET_ENDBR to functions in dl-tlsdesc.S, which are called indirectly,
> to support IBT.
>
> Tested on i686 and x86-64.
>
> * sysdeps/i386/dl-tlsdesc.S (_dl_tlsdesc_return): Add
> _CET_ENDBR.
> (_dl_tlsdesc_undefweak): Likewise.
> (_dl_tlsdesc_dynamic): Likewise.
> (_dl_tlsdesc_resolve_abs_plus_addend): Likewise.
> (_dl_tlsdesc_resolve_rel): Likewise.
> (_dl_tlsdesc_resolve_rela): Likewise.
> (_dl_tlsdesc_resolve_hold): Likewise.
> * sysdeps/x86_64/dl-tlsdesc.S (_dl_tlsdesc_return): Likewise.
> (_dl_tlsdesc_undefweak): Likewise.
> (_dl_tlsdesc_dynamic): Likewise.
> (_dl_tlsdesc_resolve_rela): Likewise.
> (_dl_tlsdesc_resolve_hold): Likewise.
Please commit.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
> ---
> sysdeps/i386/dl-tlsdesc.S | 7 +++++++
> sysdeps/x86_64/dl-tlsdesc.S | 5 +++++
> 2 files changed, 12 insertions(+)
>
> diff --git a/sysdeps/i386/dl-tlsdesc.S b/sysdeps/i386/dl-tlsdesc.S
> index 2c4764d1aa..128f0af318 100644
> --- a/sysdeps/i386/dl-tlsdesc.S
> +++ b/sysdeps/i386/dl-tlsdesc.S
> @@ -37,6 +37,7 @@
> cfi_startproc
> .align 16
> _dl_tlsdesc_return:
> + _CET_ENDBR
> movl 4(%eax), %eax
> ret
> cfi_endproc
> @@ -58,6 +59,7 @@ _dl_tlsdesc_return:
> cfi_startproc
> .align 16
> _dl_tlsdesc_undefweak:
> + _CET_ENDBR
> movl 4(%eax), %eax
> subl %gs:0, %eax
> ret
> @@ -99,6 +101,7 @@ _dl_tlsdesc_dynamic (struct tlsdesc *tdp)
> cfi_startproc
> .align 16
> _dl_tlsdesc_dynamic:
> + _CET_ENDBR
> /* Like all TLS resolvers, preserve call-clobbered registers.
> We need two scratch regs anyway. */
> subl $28, %esp
> @@ -154,6 +157,7 @@ _dl_tlsdesc_dynamic:
> .align 16
> _dl_tlsdesc_resolve_abs_plus_addend:
> 0:
> + _CET_ENDBR
> pushl %eax
> cfi_adjust_cfa_offset (4)
> pushl %ecx
> @@ -192,6 +196,7 @@ _dl_tlsdesc_resolve_abs_plus_addend:
> .align 16
> _dl_tlsdesc_resolve_rel:
> 0:
> + _CET_ENDBR
> pushl %eax
> cfi_adjust_cfa_offset (4)
> pushl %ecx
> @@ -230,6 +235,7 @@ _dl_tlsdesc_resolve_rel:
> .align 16
> _dl_tlsdesc_resolve_rela:
> 0:
> + _CET_ENDBR
> pushl %eax
> cfi_adjust_cfa_offset (4)
> pushl %ecx
> @@ -268,6 +274,7 @@ _dl_tlsdesc_resolve_rela:
> .align 16
> _dl_tlsdesc_resolve_hold:
> 0:
> + _CET_ENDBR
> pushl %eax
> cfi_adjust_cfa_offset (4)
> pushl %ecx
> diff --git a/sysdeps/x86_64/dl-tlsdesc.S b/sysdeps/x86_64/dl-tlsdesc.S
> index 437bd8cde7..80d771cd88 100644
> --- a/sysdeps/x86_64/dl-tlsdesc.S
> +++ b/sysdeps/x86_64/dl-tlsdesc.S
> @@ -37,6 +37,7 @@
> cfi_startproc
> .align 16
> _dl_tlsdesc_return:
> + _CET_ENDBR
> movq 8(%rax), %rax
> ret
> cfi_endproc
> @@ -58,6 +59,7 @@ _dl_tlsdesc_return:
> cfi_startproc
> .align 16
> _dl_tlsdesc_undefweak:
> + _CET_ENDBR
> movq 8(%rax), %rax
> subq %fs:0, %rax
> ret
> @@ -96,6 +98,7 @@ _dl_tlsdesc_dynamic (register struct tlsdesc *tdp asm ("%rax"))
> cfi_startproc
> .align 16
> _dl_tlsdesc_dynamic:
> + _CET_ENDBR
> /* Preserve call-clobbered registers that we modify.
> We need two scratch regs anyway. */
> movq %rsi, -16(%rsp)
> @@ -166,6 +169,7 @@ _dl_tlsdesc_dynamic:
> .align 16
> /* The PLT entry will have pushed the link_map pointer. */
> _dl_tlsdesc_resolve_rela:
> + _CET_ENDBR
> cfi_adjust_cfa_offset (8)
> /* Save all call-clobbered registers. Add 8 bytes for push in
> the PLT entry to align the stack. */
> @@ -216,6 +220,7 @@ _dl_tlsdesc_resolve_rela:
> .align 16
> _dl_tlsdesc_resolve_hold:
> 0:
> + _CET_ENDBR
> /* Save all call-clobbered registers. */
> subq $72, %rsp
> cfi_adjust_cfa_offset (72)
>
--
Cheers,
Carlos.
^ permalink raw reply [flat|nested] 54+ messages in thread
* [PATCH 15/24] i386: Use _CET_NOTRACK in i686/memcmp.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
2018-06-13 15:32 ` [PATCH 12/24] x86-64: Use _CET_NOTRACK in memcpy-ssse3-back.S H.J. Lu
2018-06-13 15:32 ` [PATCH 05/24] x86: Add _CET_ENDBR to functions in dl-tlsdesc.S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-06-13 15:32 ` [PATCH 07/24] i386: Add _CET_ENDBR to indirect jump targets in add_n.S/sub_n.S H.J. Lu
` (21 subsequent siblings)
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
* sysdeps/i386/i686/memcmp.S (memcmp): Add _CET_NOTRACK before
indirect jump to jump table.
---
sysdeps/i386/i686/memcmp.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/sysdeps/i386/i686/memcmp.S b/sysdeps/i386/i686/memcmp.S
index a0bc9ec97c..3259076cd7 100644
--- a/sysdeps/i386/i686/memcmp.S
+++ b/sysdeps/i386/i686/memcmp.S
@@ -80,7 +80,7 @@ L(not_1):
LOAD_JUMP_TABLE_ENTRY (L(table_32bytes), %ecx)
addl %ecx, %edx
addl %ecx, %esi
- jmp *%ebx
+ _CET_NOTRACK jmp *%ebx
ALIGN (4)
L(28bytes):
@@ -326,7 +326,7 @@ L(32bytesormore):
LOAD_JUMP_TABLE_ENTRY (L(table_32bytes), %ecx)
addl %ecx, %edx
addl %ecx, %esi
- jmp *%ebx
+ _CET_NOTRACK jmp *%ebx
L(load_ecx_28):
addl $0x4, %edx
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* [PATCH 07/24] i386: Add _CET_ENDBR to indirect jump targets in add_n.S/sub_n.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (2 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 15/24] i386: Use _CET_NOTRACK in i686/memcmp.S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-07-06 14:50 ` Carlos O'Donell
2018-06-13 15:32 ` [PATCH 18/24] i386: Use _CET_NOTRACK in memcpy-ssse3-rep.S H.J. Lu
` (20 subsequent siblings)
24 siblings, 1 reply; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
i386 add_n.S and sub_n.S use a trick to implment jump tables with LEA.
We can't use conditional branches nor normal jump tables since jump
table entries use EFLAGS set by jump table index. This patch adds
_CET_ENDBR to indirect jump targets and adjust destination for
_CET_ENDBR.
* sysdeps/i386/add_n.S: Include <sysdep.h>, instead of
"sysdep.h".
(__mpn_add_n): Save and restore %ebx if IBT is enabed. Add
_CET_ENDBR to indirect jump targets and adjust jump destination
for _CET_ENDBR.
* sysdeps/i386/i686/add_n.S: Include <sysdep.h>, instead of
"sysdep.h".
(__mpn_add_n): Save and restore %ebx if IBT is enabed. Add
_CET_ENDBR to indirect jump targets and adjust jump destination
for _CET_ENDBR.
* sysdeps/i386/sub_n.S: Include <sysdep.h>, instead of
"sysdep.h".
(__mpn_sub_n): Save and restore %ebx if IBT is enabed. Add
_CET_ENDBR to indirect jump targets and adjust jump destination
for _CET_ENDBR.
---
sysdeps/i386/add_n.S | 27 ++++++++++++++++++++++++++-
sysdeps/i386/i686/add_n.S | 27 ++++++++++++++++++++++++++-
sysdeps/i386/sub_n.S | 26 +++++++++++++++++++++++++-
3 files changed, 77 insertions(+), 3 deletions(-)
diff --git a/sysdeps/i386/add_n.S b/sysdeps/i386/add_n.S
index d6a35237b0..d3805ba213 100644
--- a/sysdeps/i386/add_n.S
+++ b/sysdeps/i386/add_n.S
@@ -17,7 +17,7 @@
along with the GNU MP Library; see the file COPYING.LIB. If not,
see <http://www.gnu.org/licenses/>. */
-#include "sysdep.h"
+#include <sysdep.h>
#include "asm-syntax.h"
#define PARMS 4+8 /* space for 2 saved regs */
@@ -40,6 +40,13 @@ ENTRY (__mpn_add_n)
cfi_rel_offset (esi, 0)
movl S2(%esp),%edx
movl SIZE(%esp),%ecx
+
+#if defined __CET__ && (__CET__ & 1) != 0
+ pushl %ebx
+ cfi_adjust_cfa_offset (4)
+ cfi_rel_offset (ebx, 0)
+#endif
+
movl %ecx,%eax
shrl $3,%ecx /* compute count for unrolled loop */
negl %eax
@@ -51,6 +58,9 @@ ENTRY (__mpn_add_n)
subl %eax,%esi /* ... by a constant when we ... */
subl %eax,%edx /* ... enter the loop */
shrl $2,%eax /* restore previous value */
+#if defined __CET__ && (__CET__ & 1) != 0
+ leal -4(,%eax,4),%ebx /* Count for 4-byte endbr32 */
+#endif
#ifdef PIC
/* Calculate start address in loop for PIC. Due to limitations in some
assemblers, Loop-L0-3 cannot be put into the leal */
@@ -64,30 +74,40 @@ L(0): leal (%eax,%eax,8),%eax
#else
/* Calculate start address in loop for non-PIC. */
leal (L(oop) - 3)(%eax,%eax,8),%eax
+#endif
+#if defined __CET__ && (__CET__ & 1) != 0
+ addl %ebx,%eax /* Adjust for endbr32 */
#endif
jmp *%eax /* jump into loop */
ALIGN (3)
L(oop): movl (%esi),%eax
adcl (%edx),%eax
movl %eax,(%edi)
+ _CET_ENDBR
movl 4(%esi),%eax
adcl 4(%edx),%eax
movl %eax,4(%edi)
+ _CET_ENDBR
movl 8(%esi),%eax
adcl 8(%edx),%eax
movl %eax,8(%edi)
+ _CET_ENDBR
movl 12(%esi),%eax
adcl 12(%edx),%eax
movl %eax,12(%edi)
+ _CET_ENDBR
movl 16(%esi),%eax
adcl 16(%edx),%eax
movl %eax,16(%edi)
+ _CET_ENDBR
movl 20(%esi),%eax
adcl 20(%edx),%eax
movl %eax,20(%edi)
+ _CET_ENDBR
movl 24(%esi),%eax
adcl 24(%edx),%eax
movl %eax,24(%edi)
+ _CET_ENDBR
movl 28(%esi),%eax
adcl 28(%edx),%eax
movl %eax,28(%edi)
@@ -100,6 +120,11 @@ L(oop): movl (%esi),%eax
sbbl %eax,%eax
negl %eax
+#if defined __CET__ && (__CET__ & 1) != 0
+ popl %ebx
+ cfi_adjust_cfa_offset (-4)
+ cfi_restore (ebx)
+#endif
popl %esi
cfi_adjust_cfa_offset (-4)
cfi_restore (esi)
diff --git a/sysdeps/i386/i686/add_n.S b/sysdeps/i386/i686/add_n.S
index 5c6c1448d6..d2d532cd30 100644
--- a/sysdeps/i386/i686/add_n.S
+++ b/sysdeps/i386/i686/add_n.S
@@ -17,7 +17,7 @@
along with the GNU MP Library; see the file COPYING.LIB. If not,
see <http://www.gnu.org/licenses/>. */
-#include "sysdep.h"
+#include <sysdep.h>
#include "asm-syntax.h"
#define PARMS 4+8 /* space for 2 saved regs */
@@ -44,6 +44,13 @@ ENTRY (__mpn_add_n)
cfi_rel_offset (esi, 0)
movl S2(%esp),%edx
movl SIZE(%esp),%ecx
+
+#if defined __CET__ && (__CET__ & 1) != 0
+ pushl %ebx
+ cfi_adjust_cfa_offset (4)
+ cfi_rel_offset (ebx, 0)
+#endif
+
movl %ecx,%eax
shrl $3,%ecx /* compute count for unrolled loop */
negl %eax
@@ -55,6 +62,9 @@ ENTRY (__mpn_add_n)
subl %eax,%esi /* ... by a constant when we ... */
subl %eax,%edx /* ... enter the loop */
shrl $2,%eax /* restore previous value */
+#if defined __CET__ && (__CET__ & 1) != 0
+ leal -4(,%eax,4),%ebx /* Count for 4-byte endbr32 */
+#endif
#ifdef PIC
/* Calculate start address in loop for PIC. */
leal (L(oop)-L(0)-3)(%eax,%eax,8),%eax
@@ -63,30 +73,40 @@ L(0):
#else
/* Calculate start address in loop for non-PIC. */
leal (L(oop) - 3)(%eax,%eax,8),%eax
+#endif
+#if defined __CET__ && (__CET__ & 1) != 0
+ addl %ebx,%eax /* Adjust for endbr32 */
#endif
jmp *%eax /* jump into loop */
ALIGN (3)
L(oop): movl (%esi),%eax
adcl (%edx),%eax
movl %eax,(%edi)
+ _CET_ENDBR
movl 4(%esi),%eax
adcl 4(%edx),%eax
movl %eax,4(%edi)
+ _CET_ENDBR
movl 8(%esi),%eax
adcl 8(%edx),%eax
movl %eax,8(%edi)
+ _CET_ENDBR
movl 12(%esi),%eax
adcl 12(%edx),%eax
movl %eax,12(%edi)
+ _CET_ENDBR
movl 16(%esi),%eax
adcl 16(%edx),%eax
movl %eax,16(%edi)
+ _CET_ENDBR
movl 20(%esi),%eax
adcl 20(%edx),%eax
movl %eax,20(%edi)
+ _CET_ENDBR
movl 24(%esi),%eax
adcl 24(%edx),%eax
movl %eax,24(%edi)
+ _CET_ENDBR
movl 28(%esi),%eax
adcl 28(%edx),%eax
movl %eax,28(%edi)
@@ -99,6 +119,11 @@ L(oop): movl (%esi),%eax
sbbl %eax,%eax
negl %eax
+#if defined __CET__ && (__CET__ & 1) != 0
+ popl %ebx
+ cfi_adjust_cfa_offset (-4)
+ cfi_restore (ebx)
+#endif
popl %esi
cfi_adjust_cfa_offset (-4)
cfi_restore (esi)
diff --git a/sysdeps/i386/sub_n.S b/sysdeps/i386/sub_n.S
index 7c6f48c32e..8f321b8c6c 100644
--- a/sysdeps/i386/sub_n.S
+++ b/sysdeps/i386/sub_n.S
@@ -17,7 +17,7 @@
along with the GNU MP Library; see the file COPYING.LIB. If not,
see <http://www.gnu.org/licenses/>. */
-#include "sysdep.h"
+#include <sysdep.h>
#include "asm-syntax.h"
#define PARMS 4+8 /* space for 2 saved regs */
@@ -40,6 +40,13 @@ ENTRY (__mpn_sub_n)
cfi_rel_offset (esi, 0)
movl S2(%esp),%edx
movl SIZE(%esp),%ecx
+
+#if defined __CET__ && (__CET__ & 1) != 0
+ pushl %ebx
+ cfi_adjust_cfa_offset (4)
+ cfi_rel_offset (ebx, 0)
+#endif
+
movl %ecx,%eax
shrl $3,%ecx /* compute count for unrolled loop */
negl %eax
@@ -51,6 +58,9 @@ ENTRY (__mpn_sub_n)
subl %eax,%esi /* ... by a constant when we ... */
subl %eax,%edx /* ... enter the loop */
shrl $2,%eax /* restore previous value */
+#if defined __CET__ && (__CET__ & 1) != 0
+ leal -4(,%eax,4),%ebx /* Count for 4-byte endbr32 */
+#endif
#ifdef PIC
/* Calculate start address in loop for PIC. Due to limitations in some
assemblers, Loop-L0-3 cannot be put into the leal */
@@ -64,30 +74,39 @@ L(0): leal (%eax,%eax,8),%eax
#else
/* Calculate start address in loop for non-PIC. */
leal (L(oop) - 3)(%eax,%eax,8),%eax
+#endif
+#if defined __CET__ && (__CET__ & 1) != 0
+ addl %ebx,%eax /* Adjust for endbr32 */
#endif
jmp *%eax /* jump into loop */
ALIGN (3)
L(oop): movl (%esi),%eax
sbbl (%edx),%eax
movl %eax,(%edi)
+ _CET_ENDBR
movl 4(%esi),%eax
sbbl 4(%edx),%eax
movl %eax,4(%edi)
+ _CET_ENDBR
movl 8(%esi),%eax
sbbl 8(%edx),%eax
movl %eax,8(%edi)
movl 12(%esi),%eax
sbbl 12(%edx),%eax
movl %eax,12(%edi)
+ _CET_ENDBR
movl 16(%esi),%eax
sbbl 16(%edx),%eax
movl %eax,16(%edi)
+ _CET_ENDBR
movl 20(%esi),%eax
sbbl 20(%edx),%eax
movl %eax,20(%edi)
+ _CET_ENDBR
movl 24(%esi),%eax
sbbl 24(%edx),%eax
movl %eax,24(%edi)
+ _CET_ENDBR
movl 28(%esi),%eax
sbbl 28(%edx),%eax
movl %eax,28(%edi)
@@ -100,6 +119,11 @@ L(oop): movl (%esi),%eax
sbbl %eax,%eax
negl %eax
+#if defined __CET__ && (__CET__ & 1) != 0
+ popl %ebx
+ cfi_adjust_cfa_offset (-4)
+ cfi_restore (ebx)
+#endif
popl %esi
cfi_adjust_cfa_offset (-4)
cfi_restore (esi)
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* Re: [PATCH 07/24] i386: Add _CET_ENDBR to indirect jump targets in add_n.S/sub_n.S
2018-06-13 15:32 ` [PATCH 07/24] i386: Add _CET_ENDBR to indirect jump targets in add_n.S/sub_n.S H.J. Lu
@ 2018-07-06 14:50 ` Carlos O'Donell
0 siblings, 0 replies; 54+ messages in thread
From: Carlos O'Donell @ 2018-07-06 14:50 UTC (permalink / raw)
To: H.J. Lu, libc-alpha
On 06/13/2018 11:31 AM, H.J. Lu wrote:
> i386 add_n.S and sub_n.S use a trick to implment jump tables with LEA.
> We can't use conditional branches nor normal jump tables since jump
> table entries use EFLAGS set by jump table index. This patch adds
> _CET_ENDBR to indirect jump targets and adjust destination for
> _CET_ENDBR.
>
> * sysdeps/i386/add_n.S: Include <sysdep.h>, instead of
> "sysdep.h".
> (__mpn_add_n): Save and restore %ebx if IBT is enabed. Add
> _CET_ENDBR to indirect jump targets and adjust jump destination
> for _CET_ENDBR.
> * sysdeps/i386/i686/add_n.S: Include <sysdep.h>, instead of
> "sysdep.h".
> (__mpn_add_n): Save and restore %ebx if IBT is enabed. Add
> _CET_ENDBR to indirect jump targets and adjust jump destination
> for _CET_ENDBR.
> * sysdeps/i386/sub_n.S: Include <sysdep.h>, instead of
> "sysdep.h".
> (__mpn_sub_n): Save and restore %ebx if IBT is enabed. Add
> _CET_ENDBR to indirect jump targets and adjust jump destination
> for _CET_ENDBR.
Please commit.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
> ---
> sysdeps/i386/add_n.S | 27 ++++++++++++++++++++++++++-
> sysdeps/i386/i686/add_n.S | 27 ++++++++++++++++++++++++++-
> sysdeps/i386/sub_n.S | 26 +++++++++++++++++++++++++-
> 3 files changed, 77 insertions(+), 3 deletions(-)
>
> diff --git a/sysdeps/i386/add_n.S b/sysdeps/i386/add_n.S
> index d6a35237b0..d3805ba213 100644
> --- a/sysdeps/i386/add_n.S
> +++ b/sysdeps/i386/add_n.S
> @@ -17,7 +17,7 @@
> along with the GNU MP Library; see the file COPYING.LIB. If not,
> see <http://www.gnu.org/licenses/>. */
>
> -#include "sysdep.h"
> +#include <sysdep.h>
OK.
> #include "asm-syntax.h"
>
> #define PARMS 4+8 /* space for 2 saved regs */
> @@ -40,6 +40,13 @@ ENTRY (__mpn_add_n)
> cfi_rel_offset (esi, 0)
> movl S2(%esp),%edx
> movl SIZE(%esp),%ecx
> +
> +#if defined __CET__ && (__CET__ & 1) != 0
> + pushl %ebx
> + cfi_adjust_cfa_offset (4)
> + cfi_rel_offset (ebx, 0)
> +#endif
OK.
> +
> movl %ecx,%eax
> shrl $3,%ecx /* compute count for unrolled loop */
> negl %eax
> @@ -51,6 +58,9 @@ ENTRY (__mpn_add_n)
> subl %eax,%esi /* ... by a constant when we ... */
> subl %eax,%edx /* ... enter the loop */
> shrl $2,%eax /* restore previous value */
> +#if defined __CET__ && (__CET__ & 1) != 0
> + leal -4(,%eax,4),%ebx /* Count for 4-byte endbr32 */
> +#endif
OK.
> #ifdef PIC
> /* Calculate start address in loop for PIC. Due to limitations in some
> assemblers, Loop-L0-3 cannot be put into the leal */
> @@ -64,30 +74,40 @@ L(0): leal (%eax,%eax,8),%eax
> #else
> /* Calculate start address in loop for non-PIC. */
> leal (L(oop) - 3)(%eax,%eax,8),%eax
> +#endif
> +#if defined __CET__ && (__CET__ & 1) != 0
> + addl %ebx,%eax /* Adjust for endbr32 */
> #endif
> jmp *%eax /* jump into loop */
> ALIGN (3)
> L(oop): movl (%esi),%eax
> adcl (%edx),%eax
> movl %eax,(%edi)
> + _CET_ENDBR
> movl 4(%esi),%eax
> adcl 4(%edx),%eax
> movl %eax,4(%edi)
> + _CET_ENDBR
> movl 8(%esi),%eax
> adcl 8(%edx),%eax
> movl %eax,8(%edi)
> + _CET_ENDBR
> movl 12(%esi),%eax
> adcl 12(%edx),%eax
> movl %eax,12(%edi)
> + _CET_ENDBR
> movl 16(%esi),%eax
> adcl 16(%edx),%eax
> movl %eax,16(%edi)
> + _CET_ENDBR
> movl 20(%esi),%eax
> adcl 20(%edx),%eax
> movl %eax,20(%edi)
> + _CET_ENDBR
> movl 24(%esi),%eax
> adcl 24(%edx),%eax
> movl %eax,24(%edi)
> + _CET_ENDBR
> movl 28(%esi),%eax
> adcl 28(%edx),%eax
> movl %eax,28(%edi)
OK.
> @@ -100,6 +120,11 @@ L(oop): movl (%esi),%eax
> sbbl %eax,%eax
> negl %eax
>
> +#if defined __CET__ && (__CET__ & 1) != 0
> + popl %ebx
> + cfi_adjust_cfa_offset (-4)
> + cfi_restore (ebx)
> +#endif
OK.
> popl %esi
> cfi_adjust_cfa_offset (-4)
> cfi_restore (esi)
> diff --git a/sysdeps/i386/i686/add_n.S b/sysdeps/i386/i686/add_n.S
> index 5c6c1448d6..d2d532cd30 100644
> --- a/sysdeps/i386/i686/add_n.S
> +++ b/sysdeps/i386/i686/add_n.S
> @@ -17,7 +17,7 @@
> along with the GNU MP Library; see the file COPYING.LIB. If not,
> see <http://www.gnu.org/licenses/>. */
>
> -#include "sysdep.h"
> +#include <sysdep.h>
> #include "asm-syntax.h"
>
> #define PARMS 4+8 /* space for 2 saved regs */
> @@ -44,6 +44,13 @@ ENTRY (__mpn_add_n)
> cfi_rel_offset (esi, 0)
> movl S2(%esp),%edx
> movl SIZE(%esp),%ecx
> +
> +#if defined __CET__ && (__CET__ & 1) != 0
> + pushl %ebx
> + cfi_adjust_cfa_offset (4)
> + cfi_rel_offset (ebx, 0)
> +#endif
> +
> movl %ecx,%eax
> shrl $3,%ecx /* compute count for unrolled loop */
> negl %eax
> @@ -55,6 +62,9 @@ ENTRY (__mpn_add_n)
> subl %eax,%esi /* ... by a constant when we ... */
> subl %eax,%edx /* ... enter the loop */
> shrl $2,%eax /* restore previous value */
> +#if defined __CET__ && (__CET__ & 1) != 0
> + leal -4(,%eax,4),%ebx /* Count for 4-byte endbr32 */
> +#endif
> #ifdef PIC
> /* Calculate start address in loop for PIC. */
> leal (L(oop)-L(0)-3)(%eax,%eax,8),%eax
> @@ -63,30 +73,40 @@ L(0):
> #else
> /* Calculate start address in loop for non-PIC. */
> leal (L(oop) - 3)(%eax,%eax,8),%eax
> +#endif
> +#if defined __CET__ && (__CET__ & 1) != 0
> + addl %ebx,%eax /* Adjust for endbr32 */
> #endif
> jmp *%eax /* jump into loop */
> ALIGN (3)
> L(oop): movl (%esi),%eax
> adcl (%edx),%eax
> movl %eax,(%edi)
> + _CET_ENDBR
> movl 4(%esi),%eax
> adcl 4(%edx),%eax
> movl %eax,4(%edi)
> + _CET_ENDBR
> movl 8(%esi),%eax
> adcl 8(%edx),%eax
> movl %eax,8(%edi)
> + _CET_ENDBR
> movl 12(%esi),%eax
> adcl 12(%edx),%eax
> movl %eax,12(%edi)
> + _CET_ENDBR
> movl 16(%esi),%eax
> adcl 16(%edx),%eax
> movl %eax,16(%edi)
> + _CET_ENDBR
> movl 20(%esi),%eax
> adcl 20(%edx),%eax
> movl %eax,20(%edi)
> + _CET_ENDBR
> movl 24(%esi),%eax
> adcl 24(%edx),%eax
> movl %eax,24(%edi)
> + _CET_ENDBR
> movl 28(%esi),%eax
> adcl 28(%edx),%eax
> movl %eax,28(%edi)
> @@ -99,6 +119,11 @@ L(oop): movl (%esi),%eax
> sbbl %eax,%eax
> negl %eax
>
> +#if defined __CET__ && (__CET__ & 1) != 0
> + popl %ebx
> + cfi_adjust_cfa_offset (-4)
> + cfi_restore (ebx)
> +#endif
> popl %esi
> cfi_adjust_cfa_offset (-4)
> cfi_restore (esi)
> diff --git a/sysdeps/i386/sub_n.S b/sysdeps/i386/sub_n.S
> index 7c6f48c32e..8f321b8c6c 100644
> --- a/sysdeps/i386/sub_n.S
> +++ b/sysdeps/i386/sub_n.S
> @@ -17,7 +17,7 @@
> along with the GNU MP Library; see the file COPYING.LIB. If not,
> see <http://www.gnu.org/licenses/>. */
>
> -#include "sysdep.h"
> +#include <sysdep.h>
> #include "asm-syntax.h"
>
> #define PARMS 4+8 /* space for 2 saved regs */
> @@ -40,6 +40,13 @@ ENTRY (__mpn_sub_n)
> cfi_rel_offset (esi, 0)
> movl S2(%esp),%edx
> movl SIZE(%esp),%ecx
> +
> +#if defined __CET__ && (__CET__ & 1) != 0
> + pushl %ebx
> + cfi_adjust_cfa_offset (4)
> + cfi_rel_offset (ebx, 0)
> +#endif
> +
> movl %ecx,%eax
> shrl $3,%ecx /* compute count for unrolled loop */
> negl %eax
> @@ -51,6 +58,9 @@ ENTRY (__mpn_sub_n)
> subl %eax,%esi /* ... by a constant when we ... */
> subl %eax,%edx /* ... enter the loop */
> shrl $2,%eax /* restore previous value */
> +#if defined __CET__ && (__CET__ & 1) != 0
> + leal -4(,%eax,4),%ebx /* Count for 4-byte endbr32 */
> +#endif
> #ifdef PIC
> /* Calculate start address in loop for PIC. Due to limitations in some
> assemblers, Loop-L0-3 cannot be put into the leal */
> @@ -64,30 +74,39 @@ L(0): leal (%eax,%eax,8),%eax
> #else
> /* Calculate start address in loop for non-PIC. */
> leal (L(oop) - 3)(%eax,%eax,8),%eax
> +#endif
> +#if defined __CET__ && (__CET__ & 1) != 0
> + addl %ebx,%eax /* Adjust for endbr32 */
> #endif
> jmp *%eax /* jump into loop */
> ALIGN (3)
> L(oop): movl (%esi),%eax
> sbbl (%edx),%eax
> movl %eax,(%edi)
> + _CET_ENDBR
> movl 4(%esi),%eax
> sbbl 4(%edx),%eax
> movl %eax,4(%edi)
> + _CET_ENDBR
> movl 8(%esi),%eax
> sbbl 8(%edx),%eax
> movl %eax,8(%edi)
> movl 12(%esi),%eax
> sbbl 12(%edx),%eax
> movl %eax,12(%edi)
> + _CET_ENDBR
> movl 16(%esi),%eax
> sbbl 16(%edx),%eax
> movl %eax,16(%edi)
> + _CET_ENDBR
> movl 20(%esi),%eax
> sbbl 20(%edx),%eax
> movl %eax,20(%edi)
> + _CET_ENDBR
> movl 24(%esi),%eax
> sbbl 24(%edx),%eax
> movl %eax,24(%edi)
> + _CET_ENDBR
> movl 28(%esi),%eax
> sbbl 28(%edx),%eax
> movl %eax,28(%edi)
> @@ -100,6 +119,11 @@ L(oop): movl (%esi),%eax
> sbbl %eax,%eax
> negl %eax
>
> +#if defined __CET__ && (__CET__ & 1) != 0
> + popl %ebx
> + cfi_adjust_cfa_offset (-4)
> + cfi_restore (ebx)
> +#endif
> popl %esi
> cfi_adjust_cfa_offset (-4)
> cfi_restore (esi)
>
OK, repeated mechanical changes.
--
Cheers,
Carlos.
^ permalink raw reply [flat|nested] 54+ messages in thread
* [PATCH 18/24] i386: Use _CET_NOTRACK in memcpy-ssse3-rep.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (3 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 07/24] i386: Add _CET_ENDBR to indirect jump targets in add_n.S/sub_n.S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-06-13 15:32 ` [PATCH 23/24] x86-64: Add endbr64 to tst-quadmod[12].S H.J. Lu
` (19 subsequent siblings)
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
* sysdeps/i386/i686/multiarch/memcpy-ssse3-rep.S
(BRANCH_TO_JMPTBL_ENTRY): Add _CET_NOTRACK before indirect jump
to jump table.
(BRANCH_TO_JMPTBL_ENTRY_TAIL): Likewise.
---
sysdeps/i386/i686/multiarch/memcpy-ssse3-rep.S | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/sysdeps/i386/i686/multiarch/memcpy-ssse3-rep.S b/sysdeps/i386/i686/multiarch/memcpy-ssse3-rep.S
index 287f1df8ca..129310bd8a 100644
--- a/sysdeps/i386/i686/multiarch/memcpy-ssse3-rep.S
+++ b/sysdeps/i386/i686/multiarch/memcpy-ssse3-rep.S
@@ -71,7 +71,7 @@
absolute address. */ \
addl (%ebx,INDEX,SCALE), %ebx; \
/* We loaded the jump table. Go. */ \
- jmp *%ebx
+ _CET_NOTRACK jmp *%ebx
# define BRANCH_TO_JMPTBL_ENTRY_VALUE(TABLE) \
addl $(TABLE - .), %ebx
@@ -79,7 +79,7 @@
# define BRANCH_TO_JMPTBL_ENTRY_TAIL(TABLE, INDEX, SCALE) \
addl (%ebx,INDEX,SCALE), %ebx; \
/* We loaded the jump table. Go. */ \
- jmp *%ebx
+ _CET_NOTRACK jmp *%ebx
#else
# define PARMS 4
# define ENTRANCE
@@ -91,12 +91,12 @@
absolute offsets. INDEX is a register contains the index into the
jump table. SCALE is the scale of INDEX. */
# define BRANCH_TO_JMPTBL_ENTRY(TABLE, INDEX, SCALE) \
- jmp *TABLE(,INDEX,SCALE)
+ _CET_NOTRACK jmp *TABLE(,INDEX,SCALE)
# define BRANCH_TO_JMPTBL_ENTRY_VALUE(TABLE)
# define BRANCH_TO_JMPTBL_ENTRY_TAIL(TABLE, INDEX, SCALE) \
- jmp *TABLE(,INDEX,SCALE)
+ _CET_NOTRACK jmp *TABLE(,INDEX,SCALE)
#endif
.section .text.ssse3,"ax",@progbits
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* [PATCH 23/24] x86-64: Add endbr64 to tst-quadmod[12].S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (4 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 18/24] i386: Use _CET_NOTRACK in memcpy-ssse3-rep.S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-06-13 15:32 ` [PATCH 13/24] x86-64: Use _CET_NOTRACK in memcmp-sse4.S H.J. Lu
` (18 subsequent siblings)
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
Add endbr64 to tst-quadmod1.S and tst-quadmod2.S so that func and foo
can be called indirectly.
* sysdeps/x86_64/tst-quadmod1.S (func): Add endbr64 if IBT is
enabled.
(foo): Likewise.
* sysdeps/x86_64/tst-quadmod2.S (func) : Likewise.
(foo): Likewise.
---
sysdeps/x86_64/tst-quadmod1.S | 6 ++++++
sysdeps/x86_64/tst-quadmod2.S | 6 ++++++
2 files changed, 12 insertions(+)
diff --git a/sysdeps/x86_64/tst-quadmod1.S b/sysdeps/x86_64/tst-quadmod1.S
index 26f2f1b599..c60f9dc89d 100644
--- a/sysdeps/x86_64/tst-quadmod1.S
+++ b/sysdeps/x86_64/tst-quadmod1.S
@@ -28,6 +28,9 @@
.type func, @function
func:
.cfi_startproc
+#if defined __CET__ && (__CET__ & 1) != 0
+ endbr64
+#endif
xorl %edi, %edi
jmp exit@PLT
.cfi_endproc
@@ -37,6 +40,9 @@ func:
foo:
.cfi_startproc
.cfi_def_cfa_register 6
+#if defined __CET__ && (__CET__ & 1) != 0
+ endbr64
+#endif
movq .Ljmp(%rip), %rax
subq $BIAS, %rax
jmp *%rax
diff --git a/sysdeps/x86_64/tst-quadmod2.S b/sysdeps/x86_64/tst-quadmod2.S
index e923adf672..af03444d4f 100644
--- a/sysdeps/x86_64/tst-quadmod2.S
+++ b/sysdeps/x86_64/tst-quadmod2.S
@@ -27,6 +27,9 @@
.type func, @function
func:
.cfi_startproc
+#if defined __CET__ && (__CET__ & 1) != 0
+ endbr64
+#endif
xorl %edi, %edi
jmp exit@PLT
.cfi_endproc
@@ -36,6 +39,9 @@ func:
foo:
.cfi_startproc
.cfi_def_cfa_register 6
+#if defined __CET__ && (__CET__ & 1) != 0
+ endbr64
+#endif
movq .Ljmp(%rip), %rax
subq $BIAS, %rax
jmp *%rax
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* [PATCH 13/24] x86-64: Use _CET_NOTRACK in memcmp-sse4.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (5 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 23/24] x86-64: Add endbr64 to tst-quadmod[12].S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-06-13 15:32 ` [PATCH 11/24] x86-64: Use _CET_NOTRACK in strcmp-sse42.S H.J. Lu
` (17 subsequent siblings)
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
* sysdeps/x86_64/multiarch/memcmp-sse4.S (BRANCH_TO_JMPTBL_ENTRY):
Add _CET_NOTRACK before indirect jump to jump table.
---
sysdeps/x86_64/multiarch/memcmp-sse4.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sysdeps/x86_64/multiarch/memcmp-sse4.S b/sysdeps/x86_64/multiarch/memcmp-sse4.S
index 0d96d6b775..8e164f2cb6 100644
--- a/sysdeps/x86_64/multiarch/memcmp-sse4.S
+++ b/sysdeps/x86_64/multiarch/memcmp-sse4.S
@@ -31,7 +31,7 @@
lea TABLE(%rip), %r11; \
movslq (%r11, INDEX, SCALE), %rcx; \
add %r11, %rcx; \
- jmp *%rcx; \
+ _CET_NOTRACK jmp *%rcx; \
ud2
/* Warning!
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* [PATCH 11/24] x86-64: Use _CET_NOTRACK in strcmp-sse42.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (6 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 13/24] x86-64: Use _CET_NOTRACK in memcmp-sse4.S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-06-13 15:32 ` [PATCH 03/24] x86: Support IBT and SHSTK in Intel CET [BZ #21598] H.J. Lu
` (16 subsequent siblings)
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
* sysdeps/x86_64/multiarch/strcmp-sse42.S (STRCMP_SSE42): Add
_CET_NOTRACK before indirect jump to jump table.
---
sysdeps/x86_64/multiarch/strcmp-sse42.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sysdeps/x86_64/multiarch/strcmp-sse42.S b/sysdeps/x86_64/multiarch/strcmp-sse42.S
index 5a0c6668a7..d3c07bd292 100644
--- a/sysdeps/x86_64/multiarch/strcmp-sse42.S
+++ b/sysdeps/x86_64/multiarch/strcmp-sse42.S
@@ -275,7 +275,7 @@ LABEL(bigger):
movslq (%r10, %r9,4), %r9
pcmpeqb %xmm1, D(%xmm0) /* Any null chars? */
lea (%r10, %r9), %r10
- jmp *%r10 /* jump to corresponding case */
+ _CET_NOTRACK jmp *%r10 /* jump to corresponding case */
/*
* The following cases will be handled by ashr_0
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* [PATCH 03/24] x86: Support IBT and SHSTK in Intel CET [BZ #21598]
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (7 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 11/24] x86-64: Use _CET_NOTRACK in strcmp-sse42.S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-07-06 19:47 ` Carlos O'Donell
2018-06-13 15:32 ` [PATCH 20/24] i386: Use _CET_NOTRACK in strcpy-sse2.S H.J. Lu
` (15 subsequent siblings)
24 siblings, 1 reply; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
Intel Control-flow Enforcement Technology (CET) instructions:
https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-en
forcement-technology-preview.pdf
includes Indirect Branch Tracking (IBT) and Shadow Stack (SHSTK).
GNU_PROPERTY_X86_FEATURE_1_IBT is added to GNU program property to
indicate that all executable sections are compatible with IBT when
ENDBR instruction starts each valid target where an indirect branch
instruction can land. Linker sets GNU_PROPERTY_X86_FEATURE_1_IBT on
output only if it is set on all relocatable inputs.
On an IBT capable processor, the following steps should be taken:
1. When loading an executable without an interpreter, enable IBT and
lock IBT if GNU_PROPERTY_X86_FEATURE_1_IBT is set on the executable.
2. When loading an executable with an interpreter, enable IBT if
GNU_PROPERTY_X86_FEATURE_1_IBT is set on the interpreter.
a. If GNU_PROPERTY_X86_FEATURE_1_IBT isn't set on the executable,
disable IBT.
b. Lock IBT.
3. If IBT is enabled, when loading a shared object without
GNU_PROPERTY_X86_FEATURE_1_IBT:
a. If legacy interwork is allowed, then mark all pages in executable
PT_LOAD segments in legacy code page bitmap. Failure of legacy code
page bitmap allocation causes an error.
b. If legacy interwork isn't allowed, it causes an error.
GNU_PROPERTY_X86_FEATURE_1_SHSTK is added to GNU program property to
indicate that all executable sections are compatible with SHSTK where
return address popped from shadow stack always matches return address
popped from normal stack. Linker sets GNU_PROPERTY_X86_FEATURE_1_SHSTK
on output only if it is set on all relocatable inputs.
On a SHSTK capable processor, the following steps should be taken:
1. When loading an executable without an interpreter, enable SHSTK if
GNU_PROPERTY_X86_FEATURE_1_SHSTK is set on the executable.
2. When loading an executable with an interpreter, enable SHSTK if
GNU_PROPERTY_X86_FEATURE_1_SHSTK is set on interpreter.
a. If GNU_PROPERTY_X86_FEATURE_1_SHSTK isn't set on the executable
or any shared objects loaded via the DT_NEEDED tag, disable SHSTK.
b. Otherwise lock SHSTK.
3. After SHSTK is enabled, it is an error to load a shared object
without GNU_PROPERTY_X86_FEATURE_1_SHSTK.
To enable CET support in glibc, --enable-cet is required to configure
glibc. When CET is enabled, both compiler and assembler must support
CET. Otherwise, it is a configure-time error.
To support CET run-time control,
1. _dl_x86_feature_1 is added to the writable ld.so namespace to indicate
if IBT or SHSTK are enabled at run-time. It should be initialized by
init_cpu_features.
2. For dynamic executables:
a. A l_cet field is added to struct link_map to indicate if IBT or
SHSTK is enabled in an ELF module. The optional DL_PROCESS_PT_NOTE
is called to process PT_NOTE segment for GNU program property and
set l_cet.
b. _dl_start_user calls _dl_cet_init, instead of _dl_init, which sets
up IBT and SHSTK.
c. DL_OPEN_CHECK is added to check IBT and SHSTK compatibilty when
dlopening a shared object.
3. Replace i386 _dl_runtime_resolve and _dl_runtime_profile with
_dl_runtime_resolve_shstk and _dl_runtime_profile_shstk, respectively if
SHSTK is enabled.
<cet.h> from CET-enabled GCC is automatically included by assembly codes
to add GNU_PROPERTY_X86_FEATURE_1_IBT and GNU_PROPERTY_X86_FEATURE_1_SHSTK
to GNU program property. _CET_ENDBR is added at the entrance of all
assembly functions whose address may be taken. _CET_NOTRACK is used to
insert NOTRACK prefix with indirect jump table to support IBT. It is
defined as notrack when _CET_NOTRACK is defined in <cet.h>.
[BZ #21598]
* configure.ac: Add --enable-cet.
* configure: Regenerated.
* elf/dl-load.c (filebuf): Moved before "dynamic-link.h".
(_dl_map_object_from_fd): Call DL_PROCESS_PT_NOTE on PT_NOTE
segment if DL_PROCESS_PT_NOTE is defined.
* elf/rtld.c (dl_main): Call DL_PROCESS_PT_NOTE on PT_NOTE
segment if DL_PROCESS_PT_NOTE is defined. Call DL_MAIN_CHECK
if DL_MAIN_CHECK is defined.
* elf/dl-open.c (dl_open_worker): Call DL_OPEN_CHECK if it is
defined.
* sysdeps/unix/sysv/linux/i386/dl-cet.c: New file.
* sysdeps/unix/sysv/linux/i386/dl-machine.h: Likewise.
* sysdeps/unix/sysv/linux/x86/check-cet.awk: Likewise.
* sysdeps/unix/sysv/linux/x86/configure: Likewise.
* sysdeps/unix/sysv/linux/x86/configure.ac: Likewise.
* sysdeps/unix/sysv/linux/x86/dl-cet.c: Likewise.
* sysdeps/unix/sysv/linux/x86/dl-cet.h: Likewise.
* sysdeps/unix/sysv/linux/x86/dl-procruntime.c: Likewise.
* sysdeps/unix/sysv/linux/x86/ldsodefs.h: Likewise.
* sysdeps/unix/sysv/linux/x86/link_map.h: Likewise.
* sysdeps/unix/sysv/linux/x86_64/dl-machine.h: Likewise.
* sysdeps/i386/dl-trampoline.S (_dl_runtime_resolve): Add
_CET_ENDBR.
(_dl_runtime_profile): Likewise.
(_dl_runtime_resolve_shstk): New.
(_dl_runtime_profile_shstk): Likewise.
* sysdeps/unix/sysv/linux/x86/Makefile (sysdep-dl-routines): Add
dl-cet if CET is enabled.
(CFLAGS-.o): Add -fcf-protection if CET is enabled.
(CFLAGS-.os): Likewise.
(CFLAGS-.op): Likewise.
(CFLAGS-.oS): Likewise.
(asm-CPPFLAGS): Add -fcf-protection -include cet.h if CET
is enabled.
(tests-special): Add $(objpfx)check-cet.out.
(cet-built-dso): New.
(+$(cet-built-dso:=.note)): Likewise.
(common-generated): Add $(cet-built-dso:$(common-objpfx)%=%.note).
($(objpfx)check-cet.out): New.
(generated): Add check-cet.out.
* sysdeps/x86/sysdep.h (_CET_NOTRACK): New.
(_CET_ENDBR): Define if not defined.
(ENTRY): Add _CET_ENDBR.
* sysdeps/x86_64/dl-trampoline.h (_dl_runtime_resolve): Add
_CET_ENDBR.
(_dl_runtime_profile): Likewise.
---
configure | 11 ++
configure.ac | 6 +
elf/dl-load.c | 61 +++---
elf/dl-open.c | 4 +
elf/rtld.c | 12 ++
sysdeps/i386/dl-trampoline.S | 72 +++++++
sysdeps/unix/sysv/linux/i386/dl-cet.c | 67 +++++++
sysdeps/unix/sysv/linux/i386/dl-machine.h | 23 +++
sysdeps/unix/sysv/linux/x86/Makefile | 42 +++++
sysdeps/unix/sysv/linux/x86/check-cet.awk | 53 ++++++
sysdeps/unix/sysv/linux/x86/configure | 69 +++++++
sysdeps/unix/sysv/linux/x86/configure.ac | 46 +++++
sysdeps/unix/sysv/linux/x86/dl-cet.c | 186 +++++++++++++++++++
sysdeps/unix/sysv/linux/x86/dl-cet.h | 138 ++++++++++++++
sysdeps/unix/sysv/linux/x86/dl-procruntime.c | 57 ++++++
sysdeps/unix/sysv/linux/x86/ldsodefs.h | 29 +++
sysdeps/unix/sysv/linux/x86/link_map.h | 26 +++
sysdeps/unix/sysv/linux/x86_64/dl-machine.h | 27 +++
sysdeps/x86/cpu-features.h | 5 +
sysdeps/x86/sysdep.h | 8 +
sysdeps/x86_64/dl-trampoline.h | 2 +
21 files changed, 919 insertions(+), 25 deletions(-)
create mode 100644 sysdeps/unix/sysv/linux/i386/dl-cet.c
create mode 100644 sysdeps/unix/sysv/linux/i386/dl-machine.h
create mode 100644 sysdeps/unix/sysv/linux/x86/check-cet.awk
create mode 100644 sysdeps/unix/sysv/linux/x86/configure
create mode 100644 sysdeps/unix/sysv/linux/x86/configure.ac
create mode 100644 sysdeps/unix/sysv/linux/x86/dl-cet.c
create mode 100644 sysdeps/unix/sysv/linux/x86/dl-cet.h
create mode 100644 sysdeps/unix/sysv/linux/x86/dl-procruntime.c
create mode 100644 sysdeps/unix/sysv/linux/x86/ldsodefs.h
create mode 100644 sysdeps/unix/sysv/linux/x86/link_map.h
create mode 100644 sysdeps/unix/sysv/linux/x86_64/dl-machine.h
diff --git a/configure b/configure
index 7a8bd3f817..f512c401dd 100755
--- a/configure
+++ b/configure
@@ -788,6 +788,7 @@ enable_nscd
enable_pt_chown
enable_tunables
enable_mathvec
+enable_cet
with_cpu
'
ac_precious_vars='build_alias
@@ -1461,6 +1462,8 @@ Optional Features:
'no' and 'valstring'
--enable-mathvec Enable building and installing mathvec [default
depends on architecture]
+ --enable-cet enable Intel Control-flow Enforcement Technology
+ (CET), x86 only
Optional Packages:
--with-PACKAGE[=ARG] use PACKAGE [ARG=yes]
@@ -3741,6 +3744,14 @@ else
fi
+# Check whether --enable-cet was given.
+if test "${enable_cet+set}" = set; then :
+ enableval=$enable_cet; enable_cet=$enableval
+else
+ enable_cet=no
+fi
+
+
# We keep the original values in `$config_*' and never modify them, so we
# can write them unchanged into config.make. Everything else uses
# $machine, $vendor, and $os, and changes them whenever convenient.
diff --git a/configure.ac b/configure.ac
index ca1282a6b3..d342227f7a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -453,6 +453,12 @@ AC_ARG_ENABLE([mathvec],
[build_mathvec=$enableval],
[build_mathvec=notset])
+AC_ARG_ENABLE([cet],
+ AC_HELP_STRING([--enable-cet],
+ [enable Intel Control-flow Enforcement Technology (CET), x86 only]),
+ [enable_cet=$enableval],
+ [enable_cet=no])
+
# We keep the original values in `$config_*' and never modify them, so we
# can write them unchanged into config.make. Everything else uses
# $machine, $vendor, and $os, and changes them whenever convenient.
diff --git a/elf/dl-load.c b/elf/dl-load.c
index e81601f36d..6197124d02 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -30,6 +30,32 @@
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/types.h>
+
+/* Type for the buffer we put the ELF header and hopefully the program
+ header. This buffer does not really have to be too large. In most
+ cases the program header follows the ELF header directly. If this
+ is not the case all bets are off and we can make the header
+ arbitrarily large and still won't get it read. This means the only
+ question is how large are the ELF and program header combined. The
+ ELF header 32-bit files is 52 bytes long and in 64-bit files is 64
+ bytes long. Each program header entry is again 32 and 56 bytes
+ long respectively. I.e., even with a file which has 10 program
+ header entries we only have to read 372B/624B respectively. Add to
+ this a bit of margin for program notes and reading 512B and 832B
+ for 32-bit and 64-bit files respecitvely is enough. If this
+ heuristic should really fail for some file the code in
+ `_dl_map_object_from_fd' knows how to recover. */
+struct filebuf
+{
+ ssize_t len;
+#if __WORDSIZE == 32
+# define FILEBUF_SIZE 512
+#else
+# define FILEBUF_SIZE 832
+#endif
+ char buf[FILEBUF_SIZE] __attribute__ ((aligned (__alignof (ElfW(Ehdr)))));
+};
+
#include "dynamic-link.h"
#include <abi-tag.h>
#include <stackinfo.h>
@@ -69,31 +95,6 @@ int __stack_prot attribute_hidden attribute_relro
#endif
-/* Type for the buffer we put the ELF header and hopefully the program
- header. This buffer does not really have to be too large. In most
- cases the program header follows the ELF header directly. If this
- is not the case all bets are off and we can make the header
- arbitrarily large and still won't get it read. This means the only
- question is how large are the ELF and program header combined. The
- ELF header 32-bit files is 52 bytes long and in 64-bit files is 64
- bytes long. Each program header entry is again 32 and 56 bytes
- long respectively. I.e., even with a file which has 10 program
- header entries we only have to read 372B/624B respectively. Add to
- this a bit of margin for program notes and reading 512B and 832B
- for 32-bit and 64-bit files respecitvely is enough. If this
- heuristic should really fail for some file the code in
- `_dl_map_object_from_fd' knows how to recover. */
-struct filebuf
-{
- ssize_t len;
-#if __WORDSIZE == 32
-# define FILEBUF_SIZE 512
-#else
-# define FILEBUF_SIZE 832
-#endif
- char buf[FILEBUF_SIZE] __attribute__ ((aligned (__alignof (ElfW(Ehdr)))));
-};
-
/* This is the decomposed LD_LIBRARY_PATH search path. */
static struct r_search_path_struct env_path_list attribute_relro;
@@ -1150,6 +1151,16 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
l->l_relro_addr = ph->p_vaddr;
l->l_relro_size = ph->p_memsz;
break;
+
+#ifdef DL_PROCESS_PT_NOTE
+ case PT_NOTE:
+ if (DL_PROCESS_PT_NOTE (l, ph, fd, fbp))
+ {
+ errstring = N_("cannot process note segment");
+ goto call_lose;
+ }
+ break;
+#endif
}
if (__glibc_unlikely (nloadcmds == 0))
diff --git a/elf/dl-open.c b/elf/dl-open.c
index 9dde4acfbc..f3bc41cb47 100644
--- a/elf/dl-open.c
+++ b/elf/dl-open.c
@@ -291,6 +291,10 @@ dl_open_worker (void *a)
_dl_debug_state ();
LIBC_PROBE (map_complete, 3, args->nsid, r, new);
+#ifdef DL_OPEN_CHECK
+ DL_OPEN_CHECK (new);
+#endif
+
/* Print scope information. */
if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_SCOPES))
_dl_show_scope (new, 0);
diff --git a/elf/rtld.c b/elf/rtld.c
index 8c732adb68..04b692908d 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -1241,6 +1241,14 @@ of this helper program; chances are you did not intend to run this program.\n\
main_map->l_relro_addr = ph->p_vaddr;
main_map->l_relro_size = ph->p_memsz;
break;
+
+#ifdef DL_PROCESS_PT_NOTE
+ case PT_NOTE:
+ if (DL_PROCESS_PT_NOTE (main_map, ph))
+ _dl_error_printf ("\
+ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
+ break;
+#endif
}
/* Adjust the address of the TLS initialization image in case
@@ -2110,6 +2118,10 @@ ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
_dl_show_scope (l, 0);
}
+#ifdef DL_MAIN_CHECK
+ DL_MAIN_CHECK (main_map, _dl_argv[0]);
+#endif
+
if (prelinked)
{
if (main_map->l_info [ADDRIDX (DT_GNU_CONFLICT)] != NULL)
diff --git a/sysdeps/i386/dl-trampoline.S b/sysdeps/i386/dl-trampoline.S
index 8bf86f8fd9..6dc0319216 100644
--- a/sysdeps/i386/dl-trampoline.S
+++ b/sysdeps/i386/dl-trampoline.S
@@ -32,6 +32,7 @@
.align 16
_dl_runtime_resolve:
cfi_adjust_cfa_offset (8)
+ _CET_ENDBR
pushl %eax # Preserve registers otherwise clobbered.
cfi_adjust_cfa_offset (4)
pushl %ecx
@@ -50,14 +51,85 @@ _dl_runtime_resolve:
cfi_endproc
.size _dl_runtime_resolve, .-_dl_runtime_resolve
+# The SHSTK compatible version.
+ .text
+ .globl _dl_runtime_resolve_shstk
+ .type _dl_runtime_resolve_shstk, @function
+ cfi_startproc
+ .align 16
+_dl_runtime_resolve_shstk:
+ cfi_adjust_cfa_offset (8)
+ _CET_ENDBR
+ pushl %eax # Preserve registers otherwise clobbered.
+ cfi_adjust_cfa_offset (4)
+ pushl %edx
+ cfi_adjust_cfa_offset (4)
+ movl 12(%esp), %edx # Copy args pushed by PLT in register. Note
+ movl 8(%esp), %eax # that `fixup' takes its parameters in regs.
+ call _dl_fixup # Call resolver.
+ movl (%esp), %edx # Get register content back.
+ movl %eax, %ecx # Store the function address.
+ movl 4(%esp), %eax # Get register content back.
+ addl $16, %esp # Adjust stack: PLT1 + PLT2 + %eax + %edx
+ cfi_adjust_cfa_offset (-16)
+ jmp *%ecx # Jump to function address.
+ cfi_endproc
+ .size _dl_runtime_resolve_shstk, .-_dl_runtime_resolve_shstk
#ifndef PROF
+# The SHSTK compatible version.
+ .globl _dl_runtime_profile_shstk
+ .type _dl_runtime_profile_shstk, @function
+ cfi_startproc
+ .align 16
+_dl_runtime_profile_shstk:
+ cfi_adjust_cfa_offset (8)
+ _CET_ENDBR
+ pushl %esp
+ cfi_adjust_cfa_offset (4)
+ addl $8, (%esp) # Account for the pushed PLT data
+ pushl %ebp
+ cfi_adjust_cfa_offset (4)
+ pushl %eax # Preserve registers otherwise clobbered.
+ cfi_adjust_cfa_offset (4)
+ pushl %ecx
+ cfi_adjust_cfa_offset (4)
+ pushl %edx
+ cfi_adjust_cfa_offset (4)
+ movl %esp, %ecx
+ subl $8, %esp
+ cfi_adjust_cfa_offset (8)
+ movl $-1, 4(%esp)
+ leal 4(%esp), %edx
+ movl %edx, (%esp)
+ pushl %ecx # Address of the register structure
+ cfi_adjust_cfa_offset (4)
+ movl 40(%esp), %ecx # Load return address
+ movl 36(%esp), %edx # Copy args pushed by PLT in register. Note
+ movl 32(%esp), %eax # that `fixup' takes its parameters in regs.
+ call _dl_profile_fixup # Call resolver.
+ cfi_adjust_cfa_offset (-8)
+ movl (%esp), %edx
+ testl %edx, %edx
+ jns 1f
+ movl 4(%esp), %edx # Get register content back.
+ movl %eax, %ecx # Store the function address.
+ movl 12(%esp), %eax # Get register content back.
+ # Adjust stack: PLT1 + PLT2 + %esp + %ebp + %eax + %ecx + %edx
+ # + free.
+ addl $32, %esp
+ cfi_adjust_cfa_offset (-32)
+ jmp *%ecx # Jump to function address.
+ cfi_endproc
+ .size _dl_runtime_profile_shstk, .-_dl_runtime_profile_shstk
+
.globl _dl_runtime_profile
.type _dl_runtime_profile, @function
cfi_startproc
.align 16
_dl_runtime_profile:
cfi_adjust_cfa_offset (8)
+ _CET_ENDBR
pushl %esp
cfi_adjust_cfa_offset (4)
addl $8, (%esp) # Account for the pushed PLT data
diff --git a/sysdeps/unix/sysv/linux/i386/dl-cet.c b/sysdeps/unix/sysv/linux/i386/dl-cet.c
new file mode 100644
index 0000000000..d9d80e151c
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/i386/dl-cet.c
@@ -0,0 +1,67 @@
+/* Linux/i386 CET initializers function.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+
+#define LINKAGE static inline
+#define _dl_cet_check cet_check
+#include <sysdeps/unix/sysv/linux/x86/dl-cet.c>
+#undef _dl_cet_check
+
+#ifdef SHARED
+void
+_dl_cet_check (struct link_map *main_map, const char *program)
+{
+ cet_check (main_map, program);
+
+ if ((GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_SHSTK))
+ {
+ /* Replace _dl_runtime_resolve and _dl_runtime_profile with
+ _dl_runtime_resolve_shstk and _dl_runtime_profile_shstk,
+ respectively if SHSTK is enabled. */
+ extern void _dl_runtime_resolve (Elf32_Word) attribute_hidden;
+ extern void _dl_runtime_resolve_shstk (Elf32_Word) attribute_hidden;
+ extern void _dl_runtime_profile (Elf32_Word) attribute_hidden;
+ extern void _dl_runtime_profile_shstk (Elf32_Word) attribute_hidden;
+ unsigned int i;
+ struct link_map *l;
+ Elf32_Addr *got;
+
+ if (main_map->l_info[DT_JMPREL])
+ {
+ got = (Elf32_Addr *) D_PTR (main_map, l_info[DT_PLTGOT]);
+ if (got[2] == (Elf32_Addr) &_dl_runtime_resolve)
+ got[2] = (Elf32_Addr) &_dl_runtime_resolve_shstk;
+ else if (got[2] == (Elf32_Addr) &_dl_runtime_profile)
+ got[2] = (Elf32_Addr) &_dl_runtime_profile_shstk;
+ }
+
+ i = main_map->l_searchlist.r_nlist;
+ while (i-- > 0)
+ {
+ l = main_map->l_initfini[i];
+ if (l->l_info[DT_JMPREL])
+ {
+ got = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
+ if (got[2] == (Elf32_Addr) &_dl_runtime_resolve)
+ got[2] = (Elf32_Addr) &_dl_runtime_resolve_shstk;
+ else if (got[2] == (Elf32_Addr) &_dl_runtime_profile)
+ got[2] = (Elf32_Addr) &_dl_runtime_profile_shstk;
+ }
+ }
+ }
+}
+#endif
diff --git a/sysdeps/unix/sysv/linux/i386/dl-machine.h b/sysdeps/unix/sysv/linux/i386/dl-machine.h
new file mode 100644
index 0000000000..3c2894edf2
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/i386/dl-machine.h
@@ -0,0 +1,23 @@
+/* Machine-dependent ELF dynamic relocation inline functions.
+ Linux/i386 version.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifdef __CET__
+# include <sysdeps/unix/sysv/linux/x86/dl-cet.h>
+#endif
+#include <sysdeps/i386/dl-machine.h>
diff --git a/sysdeps/unix/sysv/linux/x86/Makefile b/sysdeps/unix/sysv/linux/x86/Makefile
index 111ff9ff58..00be6cc472 100644
--- a/sysdeps/unix/sysv/linux/x86/Makefile
+++ b/sysdeps/unix/sysv/linux/x86/Makefile
@@ -23,3 +23,45 @@ endif
ifeq ($(subdir),setjmp)
tests += tst-saved_mask-1
endif
+
+ifeq ($(enable-cet),yes)
+ifeq ($(subdir),elf)
+sysdep-dl-routines += dl-cet
+endif
+
+# Add -fcf-protection to CFLAGS when CET is enabled.
+CFLAGS-.o += -fcf-protection
+CFLAGS-.os += -fcf-protection
+CFLAGS-.op += -fcf-protection
+CFLAGS-.oS += -fcf-protection
+
+# Compile assembly codes with <cet.h> when CET is enabled.
+asm-CPPFLAGS += -fcf-protection -include cet.h
+
+ifeq ($(subdir),elf)
+ifeq (yes,$(build-shared))
+tests-special += $(objpfx)check-cet.out
+endif
+
+# FIXME: Can't use all-built-dso in elf/Makefile since this file is
+# processed before elf/Makefile. Duplicate it here.
+cet-built-dso := $(common-objpfx)elf/ld.so $(common-objpfx)libc.so \
+ $(filter-out $(common-objpfx)linkobj/libc.so, \
+ $(sort $(wildcard $(addprefix $(common-objpfx), \
+ */lib*.so \
+ iconvdata/*.so))))
+
+$(cet-built-dso:=.note): %.note: %
+ @rm -f $@T
+ LC_ALL=C $(READELF) -n $< > $@T
+ test -s $@T
+ mv -f $@T $@
+common-generated += $(cet-built-dso:$(common-objpfx)%=%.note)
+
+$(objpfx)check-cet.out: $(..)sysdeps/unix/sysv/linux/x86/check-cet.awk \
+ $(cet-built-dso:=.note)
+ LC_ALL=C $(AWK) -f $^ > $@; \
+ $(evaluate-test)
+generated += check-cet.out
+endif
+endif
diff --git a/sysdeps/unix/sysv/linux/x86/check-cet.awk b/sysdeps/unix/sysv/linux/x86/check-cet.awk
new file mode 100644
index 0000000000..380d998caf
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/check-cet.awk
@@ -0,0 +1,53 @@
+# Verify that all shared objects contain the CET property.
+# Copyright (C) 2018 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+# This awk script expects to get command-line files that are each
+# the output of 'readelf -n' on a single shared object.
+# It exits successfully (0) if all of them contained the CET property.
+# It fails (1) if any didn't contain the CET property
+# It fails (2) if the input did not take the expected form.
+
+BEGIN { result = cet = sanity = 0 }
+
+function check_one(name) {
+ if (!sanity) {
+ print name ": *** input did not look like readelf -n output";
+ result = 2;
+ } else if (cet) {
+ print name ": OK";
+ } else {
+ print name ": *** no CET property found";
+ result = result ? result : 1;
+ }
+
+ cet = sanity = 0;
+}
+
+FILENAME != lastfile {
+ if (lastfile)
+ check_one(lastfile);
+ lastfile = FILENAME;
+}
+
+index ($0, "Displaying notes") != 0 { sanity = 1 }
+index ($0, "IBT") != 0 && index ($0, "SHSTK") != 0 { cet = 1 }
+
+END {
+ check_one(lastfile);
+ exit(result);
+}
diff --git a/sysdeps/unix/sysv/linux/x86/configure b/sysdeps/unix/sysv/linux/x86/configure
new file mode 100644
index 0000000000..358319d93d
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/configure
@@ -0,0 +1,69 @@
+# This file is generated from configure.ac by Autoconf. DO NOT EDIT!
+ # Local configure fragment for sysdeps/unix/sysv/linux/x86.
+
+if test x"$enable_cet" = xyes; then
+ # Check if CET can be enabled.
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether CET can be enabled" >&5
+$as_echo_n "checking whether CET can be enabled... " >&6; }
+if ${libc_cv_x86_cet_available+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ cat > conftest.c <<EOF
+#if !defined __CET__ || __CET__ != 3
+# error CET isn't available.
+#endif
+EOF
+ if { ac_try='${CC-cc} -c $CFLAGS -fcf-protection -include cet.h conftest.c 1>&5'
+ { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+ test $ac_status = 0; }; }; then
+ libc_cv_x86_cet_available=yes
+ else
+ libc_cv_x86_cet_available=no
+ fi
+ rm -rf conftest*
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_x86_cet_available" >&5
+$as_echo "$libc_cv_x86_cet_available" >&6; }
+ if test $libc_cv_x86_cet_available = yes; then
+ enable_cet=yes
+ else
+ if test x"$enable_cet" = xdefault; then
+ enable_cet=no
+ else
+ as_fn_error $? "$CC doesn't support CET" "$LINENO" 5
+ fi
+ fi
+fi
+if test $enable_cet = yes; then
+ # Check if assembler supports CET.
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $AS supports CET" >&5
+$as_echo_n "checking whether $AS supports CET... " >&6; }
+if ${libc_cv_x86_cet_as+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ cat > conftest.s <<EOF
+ incsspd %ecx
+EOF
+ if { ac_try='${CC-cc} -c $CFLAGS conftest.s -o conftest.o 1>&5'
+ { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+ test $ac_status = 0; }; }; then
+ libc_cv_x86_cet_as=yes
+ else
+ libc_cv_x86_cet_as=no
+ fi
+ rm -rf conftest*
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_x86_cet_as" >&5
+$as_echo "$libc_cv_x86_cet_as" >&6; }
+ if test $libc_cv_x86_cet_as = no; then
+ as_fn_error $? "$AS doesn't support CET" "$LINENO" 5
+ fi
+fi
+config_vars="$config_vars
+enable-cet = $enable_cet"
diff --git a/sysdeps/unix/sysv/linux/x86/configure.ac b/sysdeps/unix/sysv/linux/x86/configure.ac
new file mode 100644
index 0000000000..baccd38633
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/configure.ac
@@ -0,0 +1,46 @@
+GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.
+# Local configure fragment for sysdeps/unix/sysv/linux/x86.
+
+if test x"$enable_cet" = xyes; then
+ # Check if CET can be enabled.
+ AC_CACHE_CHECK(whether CET can be enabled,
+ libc_cv_x86_cet_available, [dnl
+cat > conftest.c <<EOF
+#if !defined __CET__ || __CET__ != 3
+# error CET isn't available.
+#endif
+EOF
+ if AC_TRY_COMMAND(${CC-cc} -c $CFLAGS -fcf-protection -include cet.h conftest.c 1>&AS_MESSAGE_LOG_FD); then
+ libc_cv_x86_cet_available=yes
+ else
+ libc_cv_x86_cet_available=no
+ fi
+ rm -rf conftest*])
+ if test $libc_cv_x86_cet_available = yes; then
+ enable_cet=yes
+ else
+ if test x"$enable_cet" = xdefault; then
+ enable_cet=no
+ else
+ AC_MSG_ERROR([$CC doesn't support CET])
+ fi
+ fi
+fi
+if test $enable_cet = yes; then
+ # Check if assembler supports CET.
+ AC_CACHE_CHECK(whether $AS supports CET,
+ libc_cv_x86_cet_as, [dnl
+cat > conftest.s <<EOF
+ incsspd %ecx
+EOF
+ if AC_TRY_COMMAND(${CC-cc} -c $CFLAGS conftest.s -o conftest.o 1>&AS_MESSAGE_LOG_FD); then
+ libc_cv_x86_cet_as=yes
+ else
+ libc_cv_x86_cet_as=no
+ fi
+ rm -rf conftest*])
+ if test $libc_cv_x86_cet_as = no; then
+ AC_MSG_ERROR([$AS doesn't support CET])
+ fi
+fi
+LIBC_CONFIG_VAR([enable-cet], [$enable_cet])
diff --git a/sysdeps/unix/sysv/linux/x86/dl-cet.c b/sysdeps/unix/sysv/linux/x86/dl-cet.c
new file mode 100644
index 0000000000..5acf19dae4
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/dl-cet.c
@@ -0,0 +1,186 @@
+/* Linux/x86 CET initializers function.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <unistd.h>
+#include <errno.h>
+#include <libintl.h>
+#include <ldsodefs.h>
+
+static int
+dl_cet_mark_legacy_region (struct link_map *l)
+{
+ /* FIXME: Mark legacy region */
+ return 0;
+}
+
+/* Check if object M is compatible with CET. */
+
+static void
+dl_cet_check (struct link_map *m, const char *program)
+{
+ /* Check if IBT is enabled by kernel. */
+ bool ibt_enabled
+ = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0;
+ /* Check if SHSTK is enabled by kernel. */
+ bool shstk_enabled
+ = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0;
+
+ if (ibt_enabled || shstk_enabled)
+ {
+ struct link_map *l = NULL;
+
+ /* Check if IBT and SHSTK are enabled in object. */
+ bool enable_ibt = ibt_enabled;
+ bool enable_shstk = shstk_enabled;
+ if (program)
+ {
+ /* Enable IBT and SHSTK only if they are enabled in executable.
+ NB: IBT and SHSTK may be disabled by environment variable:
+
+ GLIBC_TUNABLES=glibc.tune.hwcaps=-IBT,-SHSTK
+ */
+ enable_ibt &= (HAS_CPU_FEATURE (IBT)
+ && (m->l_cet & lc_ibt) != 0);
+ enable_shstk &= (HAS_CPU_FEATURE (SHSTK)
+ && (m->l_cet & lc_shstk) != 0);
+ }
+
+ /* ld.so is CET-enabled by kernel. But shared objects may not
+ support IBT nor SHSTK. */
+ if (enable_ibt || enable_shstk)
+ {
+ int res;
+ unsigned int i;
+ unsigned int first_legacy, last_legacy;
+ bool need_legacy_bitmap = false;
+
+ i = m->l_searchlist.r_nlist;
+ while (i-- > 0)
+ {
+ /* Check each shared object to see if IBT and SHSTK are
+ enabled. */
+ l = m->l_initfini[i];
+
+ if (l->l_init_called)
+ continue;
+
+#ifdef SHARED
+ /* Skip CET check for ld.so since ld.so is CET-enabled.
+ CET will be disabled later if CET isn't enabled in
+ executable. */
+ if (l == &GL(dl_rtld_map)
+ || l->l_real == &GL(dl_rtld_map)
+ || (program && l == m))
+ continue;
+#endif
+
+ if (enable_ibt && !(l->l_cet & lc_ibt))
+ {
+ /* Remember the first and last legacy objects. */
+ if (!need_legacy_bitmap)
+ last_legacy = i;
+ first_legacy = i;
+ need_legacy_bitmap = true;
+ }
+
+ /* SHSTK is enabled only if it is enabled in executable as
+ well as all shared objects. */
+ enable_shstk &= (l->l_cet & lc_shstk) != 0;
+ }
+
+ if (need_legacy_bitmap)
+ {
+ /* Put legacy shared objects in legacy bitmap. */
+ for (i = first_legacy; i <= last_legacy; i++)
+ {
+ l = m->l_initfini[i];
+
+ if (l->l_init_called || (l->l_cet & lc_ibt))
+ continue;
+
+#ifdef SHARED
+ if (l == &GL(dl_rtld_map)
+ || l->l_real == &GL(dl_rtld_map)
+ || (program && l == m))
+ continue;
+#endif
+
+ /* If IBT is enabled in executable and IBT isn't enabled
+ in this shard object, mark PT_LOAD segments with PF_X
+ in legacy code page bitmap. */
+ res = dl_cet_mark_legacy_region (l);
+ if (res != 0)
+ {
+ if (program)
+ _dl_fatal_printf ("%s: fail to mark legacy code region\n",
+ l->l_name);
+ else
+ _dl_signal_error (-res, l->l_name, "dlopen",
+ N_("fail to mark legacy code region"));
+ }
+ }
+ }
+ }
+
+ if (enable_ibt != ibt_enabled || enable_shstk != shstk_enabled)
+ {
+ if (!program)
+ {
+ /* When SHSTK is enabled, we can't dlopening a shared
+ object without SHSTK. */
+ if (enable_shstk != shstk_enabled)
+ _dl_signal_error (EINVAL, l->l_name, "dlopen",
+ N_("shadow stack isn't enabled"));
+ return;
+ }
+
+#ifdef SHARED
+ /* FIXME: Disable IBT and/or SHSTK if they are enabled in
+ ld.so, but disabled in executable or shared objects. */
+ ;
+#endif
+ }
+
+#ifdef SHARED
+ if (program && (ibt_enabled || shstk_enabled))
+ {
+ /* FIXME: Lock CET if IBT or SHSTK is enabled in executable. */
+ ;
+ }
+#endif
+ }
+}
+
+void
+_dl_cet_open_check (struct link_map *l)
+{
+ dl_cet_check (l, NULL);
+}
+
+#ifdef SHARED
+
+# ifndef LINKAGE
+# define LINKAGE
+# endif
+
+LINKAGE
+void
+_dl_cet_check (struct link_map *main_map, const char *program)
+{
+ dl_cet_check (main_map, program);
+}
+#endif /* SHARED */
diff --git a/sysdeps/unix/sysv/linux/x86/dl-cet.h b/sysdeps/unix/sysv/linux/x86/dl-cet.h
new file mode 100644
index 0000000000..97bf3918eb
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/dl-cet.h
@@ -0,0 +1,138 @@
+/* Linux/x86 CET inline functions.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef _dl_cet_h
+#define _dl_cet_h
+
+extern void _dl_cet_check (struct link_map *, const char *)
+ attribute_hidden;
+
+#define DL_MAIN_CHECK(l, n) _dl_cet_check ((l), (n))
+
+#ifdef ElfW
+static inline void __attribute__ ((unused))
+dl_process_cet_property_note (struct link_map *l,
+ const ElfW(Nhdr) *note,
+ const ElfW(Addr) size,
+ const ElfW(Addr) align)
+{
+ /* The NT_GNU_PROPERTY_TYPE_0 note must be aliged to 4 bytes in
+ 32-bit objects and to 8 bytes in 64-bit objects. Skip notes
+ with incorrect alignment. */
+ if (align != (__ELF_NATIVE_CLASS / 8))
+ return;
+
+ const ElfW(Addr) start = (ElfW(Addr)) note;
+
+ while ((ElfW(Addr)) (note + 1) - start < size)
+ {
+ /* Find the NT_GNU_PROPERTY_TYPE_0 note. */
+ if (note->n_namesz == 4
+ && note->n_type == NT_GNU_PROPERTY_TYPE_0
+ && memcmp (note + 1, "GNU", 4) == 0)
+ {
+ /* Check for invalid property. */
+ if (note->n_descsz < 8
+ || (note->n_descsz % sizeof (ElfW(Addr))) != 0)
+ break;
+
+ /* Start and end of property array. */
+ unsigned char *ptr = (unsigned char *) (note + 1) + 4;
+ unsigned char *ptr_end = ptr + note->n_descsz;
+
+ while (1)
+ {
+ unsigned int type = *(unsigned int *) ptr;
+ unsigned int datasz = *(unsigned int *) (ptr + 4);
+
+ ptr += 8;
+ if ((ptr + datasz) > ptr_end)
+ break;
+
+ if (type == GNU_PROPERTY_X86_FEATURE_1_AND
+ && datasz == 4)
+ {
+ unsigned int feature_1 = *(unsigned int *) ptr;
+ if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_IBT))
+ l->l_cet |= lc_ibt;
+ if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_SHSTK))
+ l->l_cet |= lc_shstk;
+ break;
+ }
+ }
+ }
+
+ /* NB: Note sections like .note.ABI-tag and .note.gnu.build-id are
+ aligned to 4 bytes in 64-bit ELF objects. */
+ note = ((const void *) note
+ + ELF_NOTE_NEXT_OFFSET (note->n_namesz, note->n_descsz,
+ align));
+ }
+}
+
+# ifdef FILEBUF_SIZE
+# define DL_PROCESS_PT_NOTE(l, ph, fd, fbp) \
+ dl_process_pt_note ((l), (ph), (fd), (fbp))
+
+static inline int __attribute__ ((unused))
+dl_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph,
+ int fd, struct filebuf *fbp)
+{
+ const ElfW(Nhdr) *note;
+ ElfW(Nhdr) *note_malloced = NULL;
+ ElfW(Addr) size = ph->p_filesz;
+
+ if (ph->p_offset + size <= (size_t) fbp->len)
+ note = (const void *) (fbp->buf + ph->p_offset);
+ else
+ {
+ if (size < __MAX_ALLOCA_CUTOFF)
+ note = alloca (size);
+ else
+ {
+ note_malloced = malloc (size);
+ note = note_malloced;
+ }
+ __lseek (fd, ph->p_offset, SEEK_SET);
+ if (__libc_read (fd, (void *) note, size) != size)
+ {
+ if (note_malloced)
+ free (note_malloced);
+ return -1;
+ }
+ }
+
+ dl_process_cet_property_note (l, note, size, ph->p_align);
+ if (note_malloced)
+ free (note_malloced);
+ return 0;
+}
+# else
+# define DL_PROCESS_PT_NOTE(l, ph) dl_process_pt_note ((l), (ph))
+
+static inline int __attribute__ ((unused))
+dl_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph)
+{
+ const ElfW(Nhdr) *note = (const void *) (ph->p_vaddr + l->l_addr);
+ dl_process_cet_property_note (l, note, ph->p_memsz, ph->p_align);
+ return 0;
+}
+# endif
+#endif
+
+#endif /* _dl_cet_h */
diff --git a/sysdeps/unix/sysv/linux/x86/dl-procruntime.c b/sysdeps/unix/sysv/linux/x86/dl-procruntime.c
new file mode 100644
index 0000000000..6b46815f46
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/dl-procruntime.c
@@ -0,0 +1,57 @@
+/* Data for processor runtime information. Linux/x86 version.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+/* This information must be kept in sync with the _DL_HWCAP_COUNT,
+ HWCAP_PLATFORMS_START and HWCAP_PLATFORMS_COUNT definitions in
+ dl-hwcap.h.
+
+ If anything should be added here check whether the size of each string
+ is still ok with the given array size.
+
+ All the #ifdefs in the definitions are quite irritating but
+ necessary if we want to avoid duplicating the information. There
+ are three different modes:
+
+ - PROCINFO_DECL is defined. This means we are only interested in
+ declarations.
+
+ - PROCINFO_DECL is not defined:
+
+ + if SHARED is defined the file is included in an array
+ initializer. The .element = { ... } syntax is needed.
+
+ + if SHARED is not defined a normal array initialization is
+ needed.
+ */
+
+#ifndef PROCINFO_CLASS
+# define PROCINFO_CLASS
+#endif
+
+#if !IS_IN (ldconfig)
+# if !defined PROCINFO_DECL && defined SHARED
+ ._dl_x86_feature_1
+# else
+PROCINFO_CLASS unsigned int _dl_x86_feature_1[2]
+# endif
+# if !defined SHARED || defined PROCINFO_DECL
+;
+# else
+,
+# endif
+#endif
diff --git a/sysdeps/unix/sysv/linux/x86/ldsodefs.h b/sysdeps/unix/sysv/linux/x86/ldsodefs.h
new file mode 100644
index 0000000000..bf8954b045
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/ldsodefs.h
@@ -0,0 +1,29 @@
+/* Run-time dynamic linker data structures for x86 loaded ELF shared objects.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef _LDSODEFS_H
+
+/* Get the real definitions. */
+#include_next <ldsodefs.h>
+
+#ifdef __CET__
+extern void _dl_cet_open_check (struct link_map *);
+# define DL_OPEN_CHECK(l) _dl_cet_open_check ((l))
+#endif
+
+#endif /* ldsodefs.h */
diff --git a/sysdeps/unix/sysv/linux/x86/link_map.h b/sysdeps/unix/sysv/linux/x86/link_map.h
new file mode 100644
index 0000000000..ef1206a9d2
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/link_map.h
@@ -0,0 +1,26 @@
+/* Additional fields in struct link_map. Linux/x86 version.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+/* If this object is enabled with CET. */
+enum
+ {
+ lc_none = 0, /* Not enabled with CET. */
+ lc_ibt = 1 << 0, /* Enabled with IBT. */
+ lc_shstk = 1 << 1, /* Enabled with STSHK. */
+ lc_ibt_and_shstk = lc_ibt | lc_shstk /* Enabled with both. */
+ } l_cet:2;
diff --git a/sysdeps/unix/sysv/linux/x86_64/dl-machine.h b/sysdeps/unix/sysv/linux/x86_64/dl-machine.h
new file mode 100644
index 0000000000..97cb9f187a
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86_64/dl-machine.h
@@ -0,0 +1,27 @@
+/* Machine-dependent ELF dynamic relocation inline functions.
+ Linux/x86-64 version.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifdef __CET__
+# include <sysdeps/unix/sysv/linux/x86/dl-cet.h>
+#endif
+#ifdef __ILP32__
+# include <sysdeps/x86_64/x32/dl-machine.h>
+#else
+# include <sysdeps/x86_64/dl-machine.h>
+#endif
diff --git a/sysdeps/x86/cpu-features.h b/sysdeps/x86/cpu-features.h
index 624e681e96..4e15c15e92 100644
--- a/sysdeps/x86/cpu-features.h
+++ b/sysdeps/x86/cpu-features.h
@@ -160,6 +160,11 @@ struct cpu_features
extern const struct cpu_features *__get_cpu_features (void)
__attribute__ ((const));
+# ifdef ElfW
+extern void _dl_setup_cet (const ElfW(Phdr) *, size_t, const ElfW(Addr))
+ attribute_hidden;
+# endif
+
# if defined (_LIBC) && !IS_IN (nonlib)
/* Unused for x86. */
# define INIT_ARCH()
diff --git a/sysdeps/x86/sysdep.h b/sysdeps/x86/sysdep.h
index afcb7cfd76..9843d9dff7 100644
--- a/sysdeps/x86/sysdep.h
+++ b/sysdeps/x86/sysdep.h
@@ -25,6 +25,13 @@
/* Syntactic details of assembler. */
+#ifdef _CET_ENDBR
+# define _CET_NOTRACK notrack
+#else
+# define _CET_ENDBR
+# define _CET_NOTRACK
+#endif
+
/* ELF uses byte-counts for .align, most others use log2 of count of bytes. */
#define ALIGNARG(log2) 1<<log2
#define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
@@ -36,6 +43,7 @@
.align ALIGNARG(4); \
C_LABEL(name) \
cfi_startproc; \
+ _CET_ENDBR; \
CALL_MCOUNT
#undef END
diff --git a/sysdeps/x86_64/dl-trampoline.h b/sysdeps/x86_64/dl-trampoline.h
index 298cfb3d99..a28b1e73a4 100644
--- a/sysdeps/x86_64/dl-trampoline.h
+++ b/sysdeps/x86_64/dl-trampoline.h
@@ -64,6 +64,7 @@
cfi_startproc
_dl_runtime_resolve:
cfi_adjust_cfa_offset(16) # Incorporate PLT
+ _CET_ENDBR
# if DL_RUNTIME_RESOLVE_REALIGN_STACK
# if LOCAL_STORAGE_AREA != 8
# error LOCAL_STORAGE_AREA must be 8
@@ -168,6 +169,7 @@ _dl_runtime_resolve:
_dl_runtime_profile:
cfi_startproc
cfi_adjust_cfa_offset(16) # Incorporate PLT
+ _CET_ENDBR
/* The La_x86_64_regs data structure pointed to by the
fourth paramater must be VEC_SIZE-byte aligned. This must
be explicitly enforced. We have the set up a dynamically
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* Re: [PATCH 03/24] x86: Support IBT and SHSTK in Intel CET [BZ #21598]
2018-06-13 15:32 ` [PATCH 03/24] x86: Support IBT and SHSTK in Intel CET [BZ #21598] H.J. Lu
@ 2018-07-06 19:47 ` Carlos O'Donell
2018-07-07 20:02 ` V2 " H.J. Lu
0 siblings, 1 reply; 54+ messages in thread
From: Carlos O'Donell @ 2018-07-06 19:47 UTC (permalink / raw)
To: H.J. Lu, libc-alpha
On 06/13/2018 11:31 AM, H.J. Lu wrote:
> Intel Control-flow Enforcement Technology (CET) instructions:
Reviewed.
Looking forward to v2.
> https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-en
> forcement-technology-preview.pdf
>
> includes Indirect Branch Tracking (IBT) and Shadow Stack (SHSTK).
>
> GNU_PROPERTY_X86_FEATURE_1_IBT is added to GNU program property to
> indicate that all executable sections are compatible with IBT when
> ENDBR instruction starts each valid target where an indirect branch
> instruction can land. Linker sets GNU_PROPERTY_X86_FEATURE_1_IBT on
> output only if it is set on all relocatable inputs.
>
OK.
> On an IBT capable processor, the following steps should be taken:
>
> 1. When loading an executable without an interpreter, enable IBT and
> lock IBT if GNU_PROPERTY_X86_FEATURE_1_IBT is set on the executable.
OK.
> 2. When loading an executable with an interpreter, enable IBT if
> GNU_PROPERTY_X86_FEATURE_1_IBT is set on the interpreter.
> a. If GNU_PROPERTY_X86_FEATURE_1_IBT isn't set on the executable,
> disable IBT.
> b. Lock IBT.
OK.
> 3. If IBT is enabled, when loading a shared object without
> GNU_PROPERTY_X86_FEATURE_1_IBT:
> a. If legacy interwork is allowed, then mark all pages in executable
> PT_LOAD segments in legacy code page bitmap. Failure of legacy code
> page bitmap allocation causes an error.
> b. If legacy interwork isn't allowed, it causes an error.
OK.
> GNU_PROPERTY_X86_FEATURE_1_SHSTK is added to GNU program property to
> indicate that all executable sections are compatible with SHSTK where
> return address popped from shadow stack always matches return address
> popped from normal stack. Linker sets GNU_PROPERTY_X86_FEATURE_1_SHSTK
> on output only if it is set on all relocatable inputs.
OK.
> On a SHSTK capable processor, the following steps should be taken:
>
> 1. When loading an executable without an interpreter, enable SHSTK if
> GNU_PROPERTY_X86_FEATURE_1_SHSTK is set on the executable.
> 2. When loading an executable with an interpreter, enable SHSTK if
> GNU_PROPERTY_X86_FEATURE_1_SHSTK is set on interpreter.
> a. If GNU_PROPERTY_X86_FEATURE_1_SHSTK isn't set on the executable
> or any shared objects loaded via the DT_NEEDED tag, disable SHSTK.
> b. Otherwise lock SHSTK.
> 3. After SHSTK is enabled, it is an error to load a shared object
> without GNU_PROPERTY_X86_FEATURE_1_SHSTK.
OK.
> To enable CET support in glibc, --enable-cet is required to configure
> glibc. When CET is enabled, both compiler and assembler must support
> CET. Otherwise, it is a configure-time error.
OK. Good a configure-time error is best here.
> To support CET run-time control,
>
> 1. _dl_x86_feature_1 is added to the writable ld.so namespace to indicate
> if IBT or SHSTK are enabled at run-time. It should be initialized by
> init_cpu_features.
OK.
> 2. For dynamic executables:
> a. A l_cet field is added to struct link_map to indicate if IBT or
> SHSTK is enabled in an ELF module. The optional DL_PROCESS_PT_NOTE
> is called to process PT_NOTE segment for GNU program property and
> set l_cet.
OK.
> b. _dl_start_user calls _dl_cet_init, instead of _dl_init, which sets
> up IBT and SHSTK.
OK.
> c. DL_OPEN_CHECK is added to check IBT and SHSTK compatibilty when
> dlopening a shared object.
OK.
> 3. Replace i386 _dl_runtime_resolve and _dl_runtime_profile with
> _dl_runtime_resolve_shstk and _dl_runtime_profile_shstk, respectively if
> SHSTK is enabled.
OK.
>
> <cet.h> from CET-enabled GCC is automatically included by assembly codes
> to add GNU_PROPERTY_X86_FEATURE_1_IBT and GNU_PROPERTY_X86_FEATURE_1_SHSTK
> to GNU program property. _CET_ENDBR is added at the entrance of all
> assembly functions whose address may be taken. _CET_NOTRACK is used to
> insert NOTRACK prefix with indirect jump table to support IBT. It is
> defined as notrack when _CET_NOTRACK is defined in <cet.h>.
>
OK.
> [BZ #21598]
> * configure.ac: Add --enable-cet.
> * configure: Regenerated.
> * elf/dl-load.c (filebuf): Moved before "dynamic-link.h".
> (_dl_map_object_from_fd): Call DL_PROCESS_PT_NOTE on PT_NOTE
> segment if DL_PROCESS_PT_NOTE is defined.
> * elf/rtld.c (dl_main): Call DL_PROCESS_PT_NOTE on PT_NOTE
> segment if DL_PROCESS_PT_NOTE is defined. Call DL_MAIN_CHECK
> if DL_MAIN_CHECK is defined.
> * elf/dl-open.c (dl_open_worker): Call DL_OPEN_CHECK if it is
> defined.
> * sysdeps/unix/sysv/linux/i386/dl-cet.c: New file.
> * sysdeps/unix/sysv/linux/i386/dl-machine.h: Likewise.
> * sysdeps/unix/sysv/linux/x86/check-cet.awk: Likewise.
> * sysdeps/unix/sysv/linux/x86/configure: Likewise.
> * sysdeps/unix/sysv/linux/x86/configure.ac: Likewise.
> * sysdeps/unix/sysv/linux/x86/dl-cet.c: Likewise.
> * sysdeps/unix/sysv/linux/x86/dl-cet.h: Likewise.
> * sysdeps/unix/sysv/linux/x86/dl-procruntime.c: Likewise.
> * sysdeps/unix/sysv/linux/x86/ldsodefs.h: Likewise.
> * sysdeps/unix/sysv/linux/x86/link_map.h: Likewise.
> * sysdeps/unix/sysv/linux/x86_64/dl-machine.h: Likewise.
> * sysdeps/i386/dl-trampoline.S (_dl_runtime_resolve): Add
> _CET_ENDBR.
> (_dl_runtime_profile): Likewise.
> (_dl_runtime_resolve_shstk): New.
> (_dl_runtime_profile_shstk): Likewise.
> * sysdeps/unix/sysv/linux/x86/Makefile (sysdep-dl-routines): Add
> dl-cet if CET is enabled.
> (CFLAGS-.o): Add -fcf-protection if CET is enabled.
> (CFLAGS-.os): Likewise.
> (CFLAGS-.op): Likewise.
> (CFLAGS-.oS): Likewise.
> (asm-CPPFLAGS): Add -fcf-protection -include cet.h if CET
> is enabled.
> (tests-special): Add $(objpfx)check-cet.out.
> (cet-built-dso): New.
> (+$(cet-built-dso:=.note)): Likewise.
> (common-generated): Add $(cet-built-dso:$(common-objpfx)%=%.note).
> ($(objpfx)check-cet.out): New.
> (generated): Add check-cet.out.
> * sysdeps/x86/sysdep.h (_CET_NOTRACK): New.
> (_CET_ENDBR): Define if not defined.
> (ENTRY): Add _CET_ENDBR.
> * sysdeps/x86_64/dl-trampoline.h (_dl_runtime_resolve): Add
> _CET_ENDBR.
> (_dl_runtime_profile): Likewise.
> ---
> configure | 11 ++
> configure.ac | 6 +
> elf/dl-load.c | 61 +++---
> elf/dl-open.c | 4 +
> elf/rtld.c | 12 ++
> sysdeps/i386/dl-trampoline.S | 72 +++++++
> sysdeps/unix/sysv/linux/i386/dl-cet.c | 67 +++++++
> sysdeps/unix/sysv/linux/i386/dl-machine.h | 23 +++
> sysdeps/unix/sysv/linux/x86/Makefile | 42 +++++
> sysdeps/unix/sysv/linux/x86/check-cet.awk | 53 ++++++
> sysdeps/unix/sysv/linux/x86/configure | 69 +++++++
> sysdeps/unix/sysv/linux/x86/configure.ac | 46 +++++
> sysdeps/unix/sysv/linux/x86/dl-cet.c | 186 +++++++++++++++++++
> sysdeps/unix/sysv/linux/x86/dl-cet.h | 138 ++++++++++++++
> sysdeps/unix/sysv/linux/x86/dl-procruntime.c | 57 ++++++
> sysdeps/unix/sysv/linux/x86/ldsodefs.h | 29 +++
> sysdeps/unix/sysv/linux/x86/link_map.h | 26 +++
> sysdeps/unix/sysv/linux/x86_64/dl-machine.h | 27 +++
> sysdeps/x86/cpu-features.h | 5 +
> sysdeps/x86/sysdep.h | 8 +
> sysdeps/x86_64/dl-trampoline.h | 2 +
> 21 files changed, 919 insertions(+), 25 deletions(-)
> create mode 100644 sysdeps/unix/sysv/linux/i386/dl-cet.c
> create mode 100644 sysdeps/unix/sysv/linux/i386/dl-machine.h
> create mode 100644 sysdeps/unix/sysv/linux/x86/check-cet.awk
> create mode 100644 sysdeps/unix/sysv/linux/x86/configure
> create mode 100644 sysdeps/unix/sysv/linux/x86/configure.ac
> create mode 100644 sysdeps/unix/sysv/linux/x86/dl-cet.c
> create mode 100644 sysdeps/unix/sysv/linux/x86/dl-cet.h
> create mode 100644 sysdeps/unix/sysv/linux/x86/dl-procruntime.c
> create mode 100644 sysdeps/unix/sysv/linux/x86/ldsodefs.h
> create mode 100644 sysdeps/unix/sysv/linux/x86/link_map.h
> create mode 100644 sysdeps/unix/sysv/linux/x86_64/dl-machine.h
>
[snip configure]
> diff --git a/configure.ac b/configure.ac
> index ca1282a6b3..d342227f7a 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -453,6 +453,12 @@ AC_ARG_ENABLE([mathvec],
> [build_mathvec=$enableval],
> [build_mathvec=notset])
>
> +AC_ARG_ENABLE([cet],
> + AC_HELP_STRING([--enable-cet],
> + [enable Intel Control-flow Enforcement Technology (CET), x86 only]),
> + [enable_cet=$enableval],
> + [enable_cet=no])
OK.
> +
> # We keep the original values in `$config_*' and never modify them, so we
> # can write them unchanged into config.make. Everything else uses
> # $machine, $vendor, and $os, and changes them whenever convenient.
> diff --git a/elf/dl-load.c b/elf/dl-load.c
> index e81601f36d..6197124d02 100644
> --- a/elf/dl-load.c
> +++ b/elf/dl-load.c
> @@ -30,6 +30,32 @@
> #include <sys/param.h>
> #include <sys/stat.h>
> #include <sys/types.h>
> +
> +/* Type for the buffer we put the ELF header and hopefully the program
> + header. This buffer does not really have to be too large. In most
> + cases the program header follows the ELF header directly. If this
> + is not the case all bets are off and we can make the header
> + arbitrarily large and still won't get it read. This means the only
> + question is how large are the ELF and program header combined. The
> + ELF header 32-bit files is 52 bytes long and in 64-bit files is 64
> + bytes long. Each program header entry is again 32 and 56 bytes
> + long respectively. I.e., even with a file which has 10 program
> + header entries we only have to read 372B/624B respectively. Add to
> + this a bit of margin for program notes and reading 512B and 832B
> + for 32-bit and 64-bit files respecitvely is enough. If this
> + heuristic should really fail for some file the code in
> + `_dl_map_object_from_fd' knows how to recover. */
OK.
> +struct filebuf
> +{
> + ssize_t len;
> +#if __WORDSIZE == 32
> +# define FILEBUF_SIZE 512
> +#else
> +# define FILEBUF_SIZE 832
> +#endif
> + char buf[FILEBUF_SIZE] __attribute__ ((aligned (__alignof (ElfW(Ehdr)))));
> +};> +
> #include "dynamic-link.h"
> #include <abi-tag.h>
> #include <stackinfo.h>
> @@ -69,31 +95,6 @@ int __stack_prot attribute_hidden attribute_relro
> #endif
>
>
> -/* Type for the buffer we put the ELF header and hopefully the program
> - header. This buffer does not really have to be too large. In most
> - cases the program header follows the ELF header directly. If this
> - is not the case all bets are off and we can make the header
> - arbitrarily large and still won't get it read. This means the only
> - question is how large are the ELF and program header combined. The
> - ELF header 32-bit files is 52 bytes long and in 64-bit files is 64
> - bytes long. Each program header entry is again 32 and 56 bytes
> - long respectively. I.e., even with a file which has 10 program
> - header entries we only have to read 372B/624B respectively. Add to
> - this a bit of margin for program notes and reading 512B and 832B
> - for 32-bit and 64-bit files respecitvely is enough. If this
> - heuristic should really fail for some file the code in
> - `_dl_map_object_from_fd' knows how to recover. */
> -struct filebuf
> -{
> - ssize_t len;
> -#if __WORDSIZE == 32
> -# define FILEBUF_SIZE 512
> -#else
> -# define FILEBUF_SIZE 832
> -#endif
> - char buf[FILEBUF_SIZE] __attribute__ ((aligned (__alignof (ElfW(Ehdr)))));
> -};
> -
OK.
> /* This is the decomposed LD_LIBRARY_PATH search path. */
> static struct r_search_path_struct env_path_list attribute_relro;
>
> @@ -1150,6 +1151,16 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
> l->l_relro_addr = ph->p_vaddr;
> l->l_relro_size = ph->p_memsz;
> break;
> +
> +#ifdef DL_PROCESS_PT_NOTE
> + case PT_NOTE:
> + if (DL_PROCESS_PT_NOTE (l, ph, fd, fbp))
> + {
> + errstring = N_("cannot process note segment");
> + goto call_lose;
> + }
> + break;
> +#endif
This is a typo-prone macro API. Please find a way for all arches to define
a do-nothing version of this API.
This seems like a sensible design. It's relatively cheap to walk the notes looking
for the one of interest. I don't imagine we'll get millions of notes, and if we do then
we'll have to do something else.
> }
>
> if (__glibc_unlikely (nloadcmds == 0))
> diff --git a/elf/dl-open.c b/elf/dl-open.c
> index 9dde4acfbc..f3bc41cb47 100644
> --- a/elf/dl-open.c
> +++ b/elf/dl-open.c
> @@ -291,6 +291,10 @@ dl_open_worker (void *a)
> _dl_debug_state ();
> LIBC_PROBE (map_complete, 3, args->nsid, r, new);
>
> +#ifdef DL_OPEN_CHECK
> + DL_OPEN_CHECK (new);
> +#endif
This is a typo-prone macro API. Otherwise OK.
Please find a way that we can define a generic version which is always used.
> +
> /* Print scope information. */
> if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_SCOPES))
> _dl_show_scope (new, 0);
> diff --git a/elf/rtld.c b/elf/rtld.c
> index 8c732adb68..04b692908d 100644
> --- a/elf/rtld.c
> +++ b/elf/rtld.c
> @@ -1241,6 +1241,14 @@ of this helper program; chances are you did not intend to run this program.\n\
> main_map->l_relro_addr = ph->p_vaddr;
> main_map->l_relro_size = ph->p_memsz;
> break;
> +
> +#ifdef DL_PROCESS_PT_NOTE
> + case PT_NOTE:
> + if (DL_PROCESS_PT_NOTE (main_map, ph))
> + _dl_error_printf ("\
> +ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
> + break;
> +#endif
This is a typo-prone macro API. Otherwise OK.
Please find a way that we can define a generic version which is always used.
> }
>
> /* Adjust the address of the TLS initialization image in case
> @@ -2110,6 +2118,10 @@ ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
> _dl_show_scope (l, 0);
> }
>
> +#ifdef DL_MAIN_CHECK
> + DL_MAIN_CHECK (main_map, _dl_argv[0]);
> +#endif
> +
This is a typo-prone macro API. Otherwise OK.
Please find a way that we can define a generic version which is always used.
> if (prelinked)
> {
> if (main_map->l_info [ADDRIDX (DT_GNU_CONFLICT)] != NULL)
> diff --git a/sysdeps/i386/dl-trampoline.S b/sysdeps/i386/dl-trampoline.S
> index 8bf86f8fd9..6dc0319216 100644
> --- a/sysdeps/i386/dl-trampoline.S
> +++ b/sysdeps/i386/dl-trampoline.S
> @@ -32,6 +32,7 @@
> .align 16
> _dl_runtime_resolve:
> cfi_adjust_cfa_offset (8)
> + _CET_ENDBR
OK.
> pushl %eax # Preserve registers otherwise clobbered.
> cfi_adjust_cfa_offset (4)
> pushl %ecx
> @@ -50,14 +51,85 @@ _dl_runtime_resolve:
> cfi_endproc
> .size _dl_runtime_resolve, .-_dl_runtime_resolve
>
> +# The SHSTK compatible version.
> + .text
> + .globl _dl_runtime_resolve_shstk
> + .type _dl_runtime_resolve_shstk, @function
> + cfi_startproc
> + .align 16
> +_dl_runtime_resolve_shstk:
> + cfi_adjust_cfa_offset (8)
> + _CET_ENDBR
> + pushl %eax # Preserve registers otherwise clobbered.
> + cfi_adjust_cfa_offset (4)
> + pushl %edx
> + cfi_adjust_cfa_offset (4)
> + movl 12(%esp), %edx # Copy args pushed by PLT in register. Note
> + movl 8(%esp), %eax # that `fixup' takes its parameters in regs.
> + call _dl_fixup # Call resolver.
> + movl (%esp), %edx # Get register content back.
> + movl %eax, %ecx # Store the function address.
> + movl 4(%esp), %eax # Get register content back.
> + addl $16, %esp # Adjust stack: PLT1 + PLT2 + %eax + %edx
> + cfi_adjust_cfa_offset (-16)
> + jmp *%ecx # Jump to function address.
> + cfi_endproc
> + .size _dl_runtime_resolve_shstk, .-_dl_runtime_resolve_shstk
OK.
>
> #ifndef PROF
> +# The SHSTK compatible version.
> + .globl _dl_runtime_profile_shstk
> + .type _dl_runtime_profile_shstk, @function
> + cfi_startproc
> + .align 16
> +_dl_runtime_profile_shstk:
> + cfi_adjust_cfa_offset (8)
> + _CET_ENDBR
> + pushl %esp
> + cfi_adjust_cfa_offset (4)
> + addl $8, (%esp) # Account for the pushed PLT data
> + pushl %ebp
> + cfi_adjust_cfa_offset (4)
> + pushl %eax # Preserve registers otherwise clobbered.
> + cfi_adjust_cfa_offset (4)
> + pushl %ecx
> + cfi_adjust_cfa_offset (4)
> + pushl %edx
> + cfi_adjust_cfa_offset (4)
> + movl %esp, %ecx
> + subl $8, %esp
> + cfi_adjust_cfa_offset (8)
> + movl $-1, 4(%esp)
> + leal 4(%esp), %edx
> + movl %edx, (%esp)
> + pushl %ecx # Address of the register structure
> + cfi_adjust_cfa_offset (4)
> + movl 40(%esp), %ecx # Load return address
> + movl 36(%esp), %edx # Copy args pushed by PLT in register. Note
> + movl 32(%esp), %eax # that `fixup' takes its parameters in regs.
> + call _dl_profile_fixup # Call resolver.
> + cfi_adjust_cfa_offset (-8)
> + movl (%esp), %edx
> + testl %edx, %edx
> + jns 1f
> + movl 4(%esp), %edx # Get register content back.
> + movl %eax, %ecx # Store the function address.
> + movl 12(%esp), %eax # Get register content back.
> + # Adjust stack: PLT1 + PLT2 + %esp + %ebp + %eax + %ecx + %edx
> + # + free.
> + addl $32, %esp
> + cfi_adjust_cfa_offset (-32)
> + jmp *%ecx # Jump to function address.
> + cfi_endproc
> + .size _dl_runtime_profile_shstk, .-_dl_runtime_profile_shstk
> +
OK.
> .globl _dl_runtime_profile
> .type _dl_runtime_profile, @function
> cfi_startproc
> .align 16
> _dl_runtime_profile:
> cfi_adjust_cfa_offset (8)
> + _CET_ENDBR
OK.
> pushl %esp
> cfi_adjust_cfa_offset (4)
> addl $8, (%esp) # Account for the pushed PLT data
> diff --git a/sysdeps/unix/sysv/linux/i386/dl-cet.c b/sysdeps/unix/sysv/linux/i386/dl-cet.c
> new file mode 100644
> index 0000000000..d9d80e151c
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/i386/dl-cet.c
If the trampoline is not linux-specific why is this?
> @@ -0,0 +1,67 @@
> +/* Linux/i386 CET initializers function.
> + Copyright (C) 2018 Free Software Foundation, Inc.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <http://www.gnu.org/licenses/>. */
> +
> +
> +#define LINKAGE static inline
> +#define _dl_cet_check cet_check
> +#include <sysdeps/unix/sysv/linux/x86/dl-cet.c>
> +#undef _dl_cet_check
> +
> +#ifdef SHARED
> +void
> +_dl_cet_check (struct link_map *main_map, const char *program)
> +{
> + cet_check (main_map, program);
> +
> + if ((GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_SHSTK))
> + {
> + /* Replace _dl_runtime_resolve and _dl_runtime_profile with
> + _dl_runtime_resolve_shstk and _dl_runtime_profile_shstk,
> + respectively if SHSTK is enabled. */
> + extern void _dl_runtime_resolve (Elf32_Word) attribute_hidden;
> + extern void _dl_runtime_resolve_shstk (Elf32_Word) attribute_hidden;
> + extern void _dl_runtime_profile (Elf32_Word) attribute_hidden;
> + extern void _dl_runtime_profile_shstk (Elf32_Word) attribute_hidden;
> + unsigned int i;
> + struct link_map *l;
> + Elf32_Addr *got;
> +
> + if (main_map->l_info[DT_JMPREL])
> + {
> + got = (Elf32_Addr *) D_PTR (main_map, l_info[DT_PLTGOT]);
> + if (got[2] == (Elf32_Addr) &_dl_runtime_resolve)
> + got[2] = (Elf32_Addr) &_dl_runtime_resolve_shstk;
> + else if (got[2] == (Elf32_Addr) &_dl_runtime_profile)
> + got[2] = (Elf32_Addr) &_dl_runtime_profile_shstk;
> + }
> +
> + i = main_map->l_searchlist.r_nlist;
> + while (i-- > 0)
> + {
> + l = main_map->l_initfini[i];
> + if (l->l_info[DT_JMPREL])
> + {
> + got = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
> + if (got[2] == (Elf32_Addr) &_dl_runtime_resolve)
> + got[2] = (Elf32_Addr) &_dl_runtime_resolve_shstk;
> + else if (got[2] == (Elf32_Addr) &_dl_runtime_profile)
> + got[2] = (Elf32_Addr) &_dl_runtime_profile_shstk;
> + }
> + }
> + }
> +}
This looks suspiciously a lot like what we do in dl-machine.h for
lazy setup. Is there any reason we can't put this code into the same
macros we use in dl-machine.h?
As I noted this code is in the linux-specific subdirectories, but doesn't
seem to be linux specific?
> +#endif
> diff --git a/sysdeps/unix/sysv/linux/i386/dl-machine.h b/sysdeps/unix/sysv/linux/i386/dl-machine.h
> new file mode 100644
> index 0000000000..3c2894edf2
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/i386/dl-machine.h
> @@ -0,0 +1,23 @@
> +/* Machine-dependent ELF dynamic relocation inline functions.
> + Linux/i386 version.
> + Copyright (C) 2018 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <http://www.gnu.org/licenses/>. */
> +
> +#ifdef __CET__
> +# include <sysdeps/unix/sysv/linux/x86/dl-cet.h>
> +#endif
> +#include <sysdeps/i386/dl-machine.h>
Why not include dl-cet.h directly from the generic dl-machine.h?
None of this support seems OS-specific. Other OSs could implement
CET support.
> diff --git a/sysdeps/unix/sysv/linux/x86/Makefile b/sysdeps/unix/sysv/linux/x86/Makefile
> index 111ff9ff58..00be6cc472 100644
> --- a/sysdeps/unix/sysv/linux/x86/Makefile
> +++ b/sysdeps/unix/sysv/linux/x86/Makefile
> @@ -23,3 +23,45 @@ endif
> ifeq ($(subdir),setjmp)
> tests += tst-saved_mask-1
> endif
> +
> +ifeq ($(enable-cet),yes)
> +ifeq ($(subdir),elf)
> +sysdep-dl-routines += dl-cet
OK.
> +endif
> +
> +# Add -fcf-protection to CFLAGS when CET is enabled.
> +CFLAGS-.o += -fcf-protection
> +CFLAGS-.os += -fcf-protection
> +CFLAGS-.op += -fcf-protection
> +CFLAGS-.oS += -fcf-protection
OK.
> +
> +# Compile assembly codes with <cet.h> when CET is enabled.
> +asm-CPPFLAGS += -fcf-protection -include cet.h
> +
> +ifeq ($(subdir),elf)
> +ifeq (yes,$(build-shared))
> +tests-special += $(objpfx)check-cet.out
> +endif
> +
OK.
> +# FIXME: Can't use all-built-dso in elf/Makefile since this file is
> +# processed before elf/Makefile. Duplicate it here.
OK, this FIXME is valid, it's a failing of our current layout that you
can't do what you want.
Please add a comment in the *other* copy to reference that this copy
needs to be updated also when there is a change.
> +cet-built-dso := $(common-objpfx)elf/ld.so $(common-objpfx)libc.so \
> + $(filter-out $(common-objpfx)linkobj/libc.so, \
> + $(sort $(wildcard $(addprefix $(common-objpfx), \
> + */lib*.so \
> + iconvdata/*.so))))
OK.
> +
> +$(cet-built-dso:=.note): %.note: %
> + @rm -f $@T
> + LC_ALL=C $(READELF) -n $< > $@T
> + test -s $@T
> + mv -f $@T $@
> +common-generated += $(cet-built-dso:$(common-objpfx)%=%.note)
OK.
> +
> +$(objpfx)check-cet.out: $(..)sysdeps/unix/sysv/linux/x86/check-cet.awk \
> + $(cet-built-dso:=.note)
> + LC_ALL=C $(AWK) -f $^ > $@; \
> + $(evaluate-test)
> +generated += check-cet.out
> +endif
> +endif
OK.
> diff --git a/sysdeps/unix/sysv/linux/x86/check-cet.awk b/sysdeps/unix/sysv/linux/x86/check-cet.awk
> new file mode 100644
> index 0000000000..380d998caf
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/x86/check-cet.awk
> @@ -0,0 +1,53 @@
> +# Verify that all shared objects contain the CET property.
> +# Copyright (C) 2018 Free Software Foundation, Inc.
> +# This file is part of the GNU C Library.
> +#
> +# The GNU C Library is free software; you can redistribute it and/or
> +# modify it under the terms of the GNU Lesser General Public
> +# License as published by the Free Software Foundation; either
> +# version 2.1 of the License, or (at your option) any later version.
> +#
> +# The GNU C Library is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> +# Lesser General Public License for more details.
> +#
> +# You should have received a copy of the GNU Lesser General Public
> +# License along with the GNU C Library; if not, see
> +# <http://www.gnu.org/licenses/>.
> +
> +# This awk script expects to get command-line files that are each
> +# the output of 'readelf -n' on a single shared object.
> +# It exits successfully (0) if all of them contained the CET property.
> +# It fails (1) if any didn't contain the CET property
> +# It fails (2) if the input did not take the expected form.
> +
> +BEGIN { result = cet = sanity = 0 }
> +
> +function check_one(name) {
> + if (!sanity) {
> + print name ": *** input did not look like readelf -n output";
> + result = 2;
> + } else if (cet) {
> + print name ": OK";
> + } else {
> + print name ": *** no CET property found";
> + result = result ? result : 1;
> + }
> +
> + cet = sanity = 0;
> +}
> +
> +FILENAME != lastfile {
> + if (lastfile)
> + check_one(lastfile);
> + lastfile = FILENAME;
> +}
> +
> +index ($0, "Displaying notes") != 0 { sanity = 1 }
> +index ($0, "IBT") != 0 && index ($0, "SHSTK") != 0 { cet = 1 }
> +
> +END {
> + check_one(lastfile);
> + exit(result);
> +}
OK.
[snip configure]
> diff --git a/sysdeps/unix/sysv/linux/x86/configure.ac b/sysdeps/unix/sysv/linux/x86/configure.ac
> new file mode 100644
> index 0000000000..baccd38633
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/x86/configure.ac
Is this really linux-specific?
> @@ -0,0 +1,46 @@
> +GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.
> +# Local configure fragment for sysdeps/unix/sysv/linux/x86.
> +
> +if test x"$enable_cet" = xyes; then
> + # Check if CET can be enabled.
> + AC_CACHE_CHECK(whether CET can be enabled,
> + libc_cv_x86_cet_available, [dnl
> +cat > conftest.c <<EOF
> +#if !defined __CET__ || __CET__ != 3
> +# error CET isn't available.
> +#endif
> +EOF
> + if AC_TRY_COMMAND(${CC-cc} -c $CFLAGS -fcf-protection -include cet.h conftest.c 1>&AS_MESSAGE_LOG_FD); then
> + libc_cv_x86_cet_available=yes
> + else
> + libc_cv_x86_cet_available=no
> + fi
> + rm -rf conftest*])
> + if test $libc_cv_x86_cet_available = yes; then
> + enable_cet=yes
> + else
> + if test x"$enable_cet" = xdefault; then
> + enable_cet=no
> + else
> + AC_MSG_ERROR([$CC doesn't support CET])
> + fi
> + fi
> +fi
OK.
> +if test $enable_cet = yes; then
> + # Check if assembler supports CET.
> + AC_CACHE_CHECK(whether $AS supports CET,
> + libc_cv_x86_cet_as, [dnl
> +cat > conftest.s <<EOF
> + incsspd %ecx
> +EOF
> + if AC_TRY_COMMAND(${CC-cc} -c $CFLAGS conftest.s -o conftest.o 1>&AS_MESSAGE_LOG_FD); then
> + libc_cv_x86_cet_as=yes
> + else
> + libc_cv_x86_cet_as=no
> + fi
> + rm -rf conftest*])
> + if test $libc_cv_x86_cet_as = no; then
> + AC_MSG_ERROR([$AS doesn't support CET])
> + fi
> +fi
> +LIBC_CONFIG_VAR([enable-cet], [$enable_cet])
It looks like all of this could run generically for CET support.
> diff --git a/sysdeps/unix/sysv/linux/x86/dl-cet.c b/sysdeps/unix/sysv/linux/x86/dl-cet.c
> new file mode 100644
> index 0000000000..5acf19dae4
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/x86/dl-cet.c
> @@ -0,0 +1,186 @@
> +/* Linux/x86 CET initializers function.
> + Copyright (C) 2018 Free Software Foundation, Inc.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <http://www.gnu.org/licenses/>. */
> +
> +#include <unistd.h>
> +#include <errno.h>
> +#include <libintl.h>
> +#include <ldsodefs.h>
> +
> +static int
> +dl_cet_mark_legacy_region (struct link_map *l)
> +{
> + /* FIXME: Mark legacy region */
> + return 0;
Why is there a FIXME here?
This patch should be complete or it should be an RFC.
If it is complete it should explain why no action needs to be taken in
the OS to mark legacy regions.
> +}
> +
> +/* Check if object M is compatible with CET. */
> +
> +static void
> +dl_cet_check (struct link_map *m, const char *program)
> +{
> + /* Check if IBT is enabled by kernel. */
> + bool ibt_enabled
> + = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0;
> + /* Check if SHSTK is enabled by kernel. */
> + bool shstk_enabled
> + = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0;
> +
OK.
> + if (ibt_enabled || shstk_enabled)
> + {
> + struct link_map *l = NULL;
> +
> + /* Check if IBT and SHSTK are enabled in object. */
> + bool enable_ibt = ibt_enabled;
> + bool enable_shstk = shstk_enabled;
> + if (program)
> + {
> + /* Enable IBT and SHSTK only if they are enabled in executable.
> + NB: IBT and SHSTK may be disabled by environment variable:
> +
> + GLIBC_TUNABLES=glibc.tune.hwcaps=-IBT,-SHSTK
> + */
> + enable_ibt &= (HAS_CPU_FEATURE (IBT)
> + && (m->l_cet & lc_ibt) != 0);
> + enable_shstk &= (HAS_CPU_FEATURE (SHSTK)
> + && (m->l_cet & lc_shstk) != 0);
OK.
> + }
> +
> + /* ld.so is CET-enabled by kernel. But shared objects may not
> + support IBT nor SHSTK. */
> + if (enable_ibt || enable_shstk)
> + {
> + int res;
> + unsigned int i;
> + unsigned int first_legacy, last_legacy;
> + bool need_legacy_bitmap = false;
> +
> + i = m->l_searchlist.r_nlist;
> + while (i-- > 0)
> + {
> + /* Check each shared object to see if IBT and SHSTK are
> + enabled. */
> + l = m->l_initfini[i];
> +
> + if (l->l_init_called)
> + continue;
> +
> +#ifdef SHARED
> + /* Skip CET check for ld.so since ld.so is CET-enabled.
> + CET will be disabled later if CET isn't enabled in
> + executable. */
OK.
> + if (l == &GL(dl_rtld_map)
> + || l->l_real == &GL(dl_rtld_map)
> + || (program && l == m))
> + continue;
> +#endif
> +
> + if (enable_ibt && !(l->l_cet & lc_ibt))
> + {
> + /* Remember the first and last legacy objects. */
> + if (!need_legacy_bitmap)
> + last_legacy = i;
> + first_legacy = i;
> + need_legacy_bitmap = true;
> + }
> +
> + /* SHSTK is enabled only if it is enabled in executable as
> + well as all shared objects. */
> + enable_shstk &= (l->l_cet & lc_shstk) != 0;
> + }
> +
> + if (need_legacy_bitmap)
> + {
> + /* Put legacy shared objects in legacy bitmap. */
> + for (i = first_legacy; i <= last_legacy; i++)
> + {
> + l = m->l_initfini[i];
> +
> + if (l->l_init_called || (l->l_cet & lc_ibt))
> + continue;
> +
> +#ifdef SHARED
> + if (l == &GL(dl_rtld_map)
> + || l->l_real == &GL(dl_rtld_map)
> + || (program && l == m))
> + continue;
> +#endif
> +
> + /* If IBT is enabled in executable and IBT isn't enabled
> + in this shard object, mark PT_LOAD segments with PF_X
> + in legacy code page bitmap. */
> + res = dl_cet_mark_legacy_region (l);
... which does nothing? Is the kernel side of the requirements not known yet?
> + if (res != 0)
> + {
> + if (program)
> + _dl_fatal_printf ("%s: fail to mark legacy code region\n",
> + l->l_name);
> + else
> + _dl_signal_error (-res, l->l_name, "dlopen",
> + N_("fail to mark legacy code region"));
> + }
> + }
> + }
> + }
> +
> + if (enable_ibt != ibt_enabled || enable_shstk != shstk_enabled)
> + {
> + if (!program)
> + {
> + /* When SHSTK is enabled, we can't dlopening a shared
> + object without SHSTK. */
> + if (enable_shstk != shstk_enabled)
> + _dl_signal_error (EINVAL, l->l_name, "dlopen",
> + N_("shadow stack isn't enabled"));
OK.
> + return;
> + }
> +
> +#ifdef SHARED
> + /* FIXME: Disable IBT and/or SHSTK if they are enabled in
> + ld.so, but disabled in executable or shared objects. */
> + ;
Is the code missing?
> +#endif
> + }
> +
> +#ifdef SHARED
> + if (program && (ibt_enabled || shstk_enabled))
> + {
> + /* FIXME: Lock CET if IBT or SHSTK is enabled in executable. */
> + ;
Similarly?
> + }
> +#endif
> + }
> +}
> +
> +void
> +_dl_cet_open_check (struct link_map *l)
> +{
> + dl_cet_check (l, NULL);
> +}
OK.
> +
> +#ifdef SHARED
> +
> +# ifndef LINKAGE
> +# define LINKAGE
> +# endif
> +
> +LINKAGE
> +void
> +_dl_cet_check (struct link_map *main_map, const char *program)
> +{
> + dl_cet_check (main_map, program);
> +}
> +#endif /* SHARED */
OK.
> diff --git a/sysdeps/unix/sysv/linux/x86/dl-cet.h b/sysdeps/unix/sysv/linux/x86/dl-cet.h
> new file mode 100644
> index 0000000000..97bf3918eb
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/x86/dl-cet.h
> @@ -0,0 +1,138 @@
> +/* Linux/x86 CET inline functions.
> + Copyright (C) 2018 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <http://www.gnu.org/licenses/>. */
> +
> +#ifndef _dl_cet_h
> +#define _dl_cet_h
> +
> +extern void _dl_cet_check (struct link_map *, const char *)
> + attribute_hidden;
OK.
> +
> +#define DL_MAIN_CHECK(l, n) _dl_cet_check ((l), (n))
You have to find a way to define this everywhere.
> +
> +#ifdef ElfW
> +static inline void __attribute__ ((unused))
> +dl_process_cet_property_note (struct link_map *l,
> + const ElfW(Nhdr) *note,
> + const ElfW(Addr) size,
> + const ElfW(Addr) align)
> +{
> + /* The NT_GNU_PROPERTY_TYPE_0 note must be aliged to 4 bytes in
> + 32-bit objects and to 8 bytes in 64-bit objects. Skip notes
> + with incorrect alignment. */
> + if (align != (__ELF_NATIVE_CLASS / 8))
> + return;
> +
> + const ElfW(Addr) start = (ElfW(Addr)) note;
> +
> + while ((ElfW(Addr)) (note + 1) - start < size)
OK.
> + {
> + /* Find the NT_GNU_PROPERTY_TYPE_0 note. */
> + if (note->n_namesz == 4
> + && note->n_type == NT_GNU_PROPERTY_TYPE_0
> + && memcmp (note + 1, "GNU", 4) == 0)
OK.
> + {
> + /* Check for invalid property. */
> + if (note->n_descsz < 8
> + || (note->n_descsz % sizeof (ElfW(Addr))) != 0)
> + break;
> +
> + /* Start and end of property array. */
> + unsigned char *ptr = (unsigned char *) (note + 1) + 4;
> + unsigned char *ptr_end = ptr + note->n_descsz;
> +
> + while (1)
> + {
> + unsigned int type = *(unsigned int *) ptr;
> + unsigned int datasz = *(unsigned int *) (ptr + 4);
> +
> + ptr += 8;
> + if ((ptr + datasz) > ptr_end)
> + break;
> +
> + if (type == GNU_PROPERTY_X86_FEATURE_1_AND
> + && datasz == 4)
> + {
> + unsigned int feature_1 = *(unsigned int *) ptr;
> + if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_IBT))
> + l->l_cet |= lc_ibt;
> + if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_SHSTK))
> + l->l_cet |= lc_shstk;
> + break;
> + }
OK.
> + }
> + }
> +
> + /* NB: Note sections like .note.ABI-tag and .note.gnu.build-id are
> + aligned to 4 bytes in 64-bit ELF objects. */
OK.
> + note = ((const void *) note
> + + ELF_NOTE_NEXT_OFFSET (note->n_namesz, note->n_descsz,
> + align));
> + }
> +}
> +
> +# ifdef FILEBUF_SIZE
> +# define DL_PROCESS_PT_NOTE(l, ph, fd, fbp) \
> + dl_process_pt_note ((l), (ph), (fd), (fbp))
You need to find a way to define this for all arches.
I suggest picking an existing header if you can find one, or a new one e.g. dl-check.h.
You may want to clean that up first, for example:
* We have DL_SYSDEP_OSCHECK
* With header dl-osinfo.h
You could put things in there for general undefined functions.
Then in x86 you include dl-cet.h into dl-osinfo.h.
Then it's really Linux-specific.
> +
> +static inline int __attribute__ ((unused))
> +dl_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph,
> + int fd, struct filebuf *fbp)
> +{
> + const ElfW(Nhdr) *note;
> + ElfW(Nhdr) *note_malloced = NULL;
> + ElfW(Addr) size = ph->p_filesz;
> +
> + if (ph->p_offset + size <= (size_t) fbp->len)
> + note = (const void *) (fbp->buf + ph->p_offset);
> + else
> + {
> + if (size < __MAX_ALLOCA_CUTOFF)
> + note = alloca (size);
> + else
> + {
> + note_malloced = malloc (size);
> + note = note_malloced;
> + }
> + __lseek (fd, ph->p_offset, SEEK_SET);
> + if (__libc_read (fd, (void *) note, size) != size)
> + {
> + if (note_malloced)
> + free (note_malloced);
> + return -1;
> + }
> + }
OK.
> +
> + dl_process_cet_property_note (l, note, size, ph->p_align);
> + if (note_malloced)
> + free (note_malloced);
> + return 0;
> +}
> +# else
> +# define DL_PROCESS_PT_NOTE(l, ph) dl_process_pt_note ((l), (ph))
OK.
> +
> +static inline int __attribute__ ((unused))
> +dl_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph)
> +{
> + const ElfW(Nhdr) *note = (const void *) (ph->p_vaddr + l->l_addr);
> + dl_process_cet_property_note (l, note, ph->p_memsz, ph->p_align);
> + return 0;
> +}
OK.
> +# endif
> +#endif
> +
> +#endif /* _dl_cet_h */
> diff --git a/sysdeps/unix/sysv/linux/x86/dl-procruntime.c b/sysdeps/unix/sysv/linux/x86/dl-procruntime.c
> new file mode 100644
> index 0000000000..6b46815f46
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/x86/dl-procruntime.c
> @@ -0,0 +1,57 @@
> +/* Data for processor runtime information. Linux/x86 version.
> + Copyright (C) 2018 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <http://www.gnu.org/licenses/>. */
> +
> +/* This information must be kept in sync with the _DL_HWCAP_COUNT,
> + HWCAP_PLATFORMS_START and HWCAP_PLATFORMS_COUNT definitions in
> + dl-hwcap.h.
> +
> + If anything should be added here check whether the size of each string
> + is still ok with the given array size.
> +
> + All the #ifdefs in the definitions are quite irritating but
> + necessary if we want to avoid duplicating the information. There
> + are three different modes:
> +
> + - PROCINFO_DECL is defined. This means we are only interested in
> + declarations.
> +
> + - PROCINFO_DECL is not defined:
> +
> + + if SHARED is defined the file is included in an array
> + initializer. The .element = { ... } syntax is needed.
> +
> + + if SHARED is not defined a normal array initialization is
> + needed.
> + */
> +
> +#ifndef PROCINFO_CLASS
> +# define PROCINFO_CLASS
> +#endif
> +
> +#if !IS_IN (ldconfig)
> +# if !defined PROCINFO_DECL && defined SHARED
> + ._dl_x86_feature_1
> +# else
> +PROCINFO_CLASS unsigned int _dl_x86_feature_1[2]
> +# endif
> +# if !defined SHARED || defined PROCINFO_DECL
> +;
> +# else
> +,
> +# endif
> +#endif
OK.
> diff --git a/sysdeps/unix/sysv/linux/x86/ldsodefs.h b/sysdeps/unix/sysv/linux/x86/ldsodefs.h
> new file mode 100644
> index 0000000000..bf8954b045
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/x86/ldsodefs.h
> @@ -0,0 +1,29 @@
> +/* Run-time dynamic linker data structures for x86 loaded ELF shared objects.
> + Copyright (C) 2018 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <http://www.gnu.org/licenses/>. */
> +
> +#ifndef _LDSODEFS_H
> +
> +/* Get the real definitions. */
> +#include_next <ldsodefs.h>
> +
> +#ifdef __CET__
> +extern void _dl_cet_open_check (struct link_map *);
> +# define DL_OPEN_CHECK(l) _dl_cet_open_check ((l))
> +#endif
> +
OK. Though as I note you need to find a way to always define DL_OPEN_CHECK.
> +#endif /* ldsodefs.h */
> diff --git a/sysdeps/unix/sysv/linux/x86/link_map.h b/sysdeps/unix/sysv/linux/x86/link_map.h
> new file mode 100644
> index 0000000000..ef1206a9d2
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/x86/link_map.h
> @@ -0,0 +1,26 @@
> +/* Additional fields in struct link_map. Linux/x86 version.
> + Copyright (C) 2018 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <http://www.gnu.org/licenses/>. */
> +
> +/* If this object is enabled with CET. */
> +enum
> + {
> + lc_none = 0, /* Not enabled with CET. */
> + lc_ibt = 1 << 0, /* Enabled with IBT. */
> + lc_shstk = 1 << 1, /* Enabled with STSHK. */
> + lc_ibt_and_shstk = lc_ibt | lc_shstk /* Enabled with both. */
> + } l_cet:2;
OK.
> diff --git a/sysdeps/unix/sysv/linux/x86_64/dl-machine.h b/sysdeps/unix/sysv/linux/x86_64/dl-machine.h
> new file mode 100644
> index 0000000000..97cb9f187a
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/x86_64/dl-machine.h
> @@ -0,0 +1,27 @@
> +/* Machine-dependent ELF dynamic relocation inline functions.
> + Linux/x86-64 version.
> + Copyright (C) 2018 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <http://www.gnu.org/licenses/>. */
> +
> +#ifdef __CET__
> +# include <sysdeps/unix/sysv/linux/x86/dl-cet.h>
> +#endif
> +#ifdef __ILP32__
> +# include <sysdeps/x86_64/x32/dl-machine.h>
> +#else
> +# include <sysdeps/x86_64/dl-machine.h>
> +#endif
Why do this and not just directly include dl-cet.h into the existing
non-Linux dl-machine?
CET is not Linux-specific it's a piece of hardware technology?
> diff --git a/sysdeps/x86/cpu-features.h b/sysdeps/x86/cpu-features.h
> index 624e681e96..4e15c15e92 100644
> --- a/sysdeps/x86/cpu-features.h
> +++ b/sysdeps/x86/cpu-features.h
> @@ -160,6 +160,11 @@ struct cpu_features
> extern const struct cpu_features *__get_cpu_features (void)
> __attribute__ ((const));
>
> +# ifdef ElfW
> +extern void _dl_setup_cet (const ElfW(Phdr) *, size_t, const ElfW(Addr))
> + attribute_hidden;
> +# endif
OK.
> +
> # if defined (_LIBC) && !IS_IN (nonlib)
> /* Unused for x86. */
> # define INIT_ARCH()
> diff --git a/sysdeps/x86/sysdep.h b/sysdeps/x86/sysdep.h
> index afcb7cfd76..9843d9dff7 100644
> --- a/sysdeps/x86/sysdep.h
> +++ b/sysdeps/x86/sysdep.h
> @@ -25,6 +25,13 @@
>
> /* Syntactic details of assembler. */
>
> +#ifdef _CET_ENDBR
> +# define _CET_NOTRACK notrack
> +#else
> +# define _CET_ENDBR
> +# define _CET_NOTRACK
> +#endif
OK.
> +
> /* ELF uses byte-counts for .align, most others use log2 of count of bytes. */
> #define ALIGNARG(log2) 1<<log2
> #define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
> @@ -36,6 +43,7 @@
> .align ALIGNARG(4); \
> C_LABEL(name) \
> cfi_startproc;
OK.
\
> + _CET_ENDBR; \
> CALL_MCOUNT
>
> #undef END
> diff --git a/sysdeps/x86_64/dl-trampoline.h b/sysdeps/x86_64/dl-trampoline.h
> index 298cfb3d99..a28b1e73a4 100644
> --- a/sysdeps/x86_64/dl-trampoline.h
> +++ b/sysdeps/x86_64/dl-trampoline.h
> @@ -64,6 +64,7 @@
> cfi_startproc
> _dl_runtime_resolve:
> cfi_adjust_cfa_offset(16) # Incorporate PLT
> + _CET_ENDBR
OK.
> # if DL_RUNTIME_RESOLVE_REALIGN_STACK
> # if LOCAL_STORAGE_AREA != 8
> # error LOCAL_STORAGE_AREA must be 8
> @@ -168,6 +169,7 @@ _dl_runtime_resolve:
> _dl_runtime_profile:
> cfi_startproc
> cfi_adjust_cfa_offset(16) # Incorporate PLT
> + _CET_ENDBR
OK.
> /* The La_x86_64_regs data structure pointed to by the
> fourth paramater must be VEC_SIZE-byte aligned. This must
> be explicitly enforced. We have the set up a dynamically
>
--
Cheers,
Carlos.
^ permalink raw reply [flat|nested] 54+ messages in thread* V2 [PATCH 03/24] x86: Support IBT and SHSTK in Intel CET [BZ #21598]
2018-07-06 19:47 ` Carlos O'Donell
@ 2018-07-07 20:02 ` H.J. Lu
0 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-07-07 20:02 UTC (permalink / raw)
To: Carlos O'Donell; +Cc: libc-alpha
On Fri, Jul 06, 2018 at 03:47:27PM -0400, Carlos O'Donell wrote:
> On 06/13/2018 11:31 AM, H.J. Lu wrote:
> > Intel Control-flow Enforcement Technology (CET) instructions:
>
> Reviewed.
>
> Looking forward to v2.
>
> > https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-en
> > forcement-technology-preview.pdf
> >
> > includes Indirect Branch Tracking (IBT) and Shadow Stack (SHSTK).
> >
> > GNU_PROPERTY_X86_FEATURE_1_IBT is added to GNU program property to
> > indicate that all executable sections are compatible with IBT when
> > ENDBR instruction starts each valid target where an indirect branch
> > instruction can land. Linker sets GNU_PROPERTY_X86_FEATURE_1_IBT on
> > output only if it is set on all relocatable inputs.
> >
>
> OK.
>
> > On an IBT capable processor, the following steps should be taken:
> >
> > 1. When loading an executable without an interpreter, enable IBT and
> > lock IBT if GNU_PROPERTY_X86_FEATURE_1_IBT is set on the executable.
>
> OK.
>
> > 2. When loading an executable with an interpreter, enable IBT if
> > GNU_PROPERTY_X86_FEATURE_1_IBT is set on the interpreter.
> > a. If GNU_PROPERTY_X86_FEATURE_1_IBT isn't set on the executable,
> > disable IBT.
> > b. Lock IBT.
>
> OK.
>
> > 3. If IBT is enabled, when loading a shared object without
> > GNU_PROPERTY_X86_FEATURE_1_IBT:
> > a. If legacy interwork is allowed, then mark all pages in executable
> > PT_LOAD segments in legacy code page bitmap. Failure of legacy code
> > page bitmap allocation causes an error.
> > b. If legacy interwork isn't allowed, it causes an error.
>
> OK.
>
> > GNU_PROPERTY_X86_FEATURE_1_SHSTK is added to GNU program property to
> > indicate that all executable sections are compatible with SHSTK where
> > return address popped from shadow stack always matches return address
> > popped from normal stack. Linker sets GNU_PROPERTY_X86_FEATURE_1_SHSTK
> > on output only if it is set on all relocatable inputs.
>
> OK.
>
> > On a SHSTK capable processor, the following steps should be taken:
> >
> > 1. When loading an executable without an interpreter, enable SHSTK if
> > GNU_PROPERTY_X86_FEATURE_1_SHSTK is set on the executable.
> > 2. When loading an executable with an interpreter, enable SHSTK if
> > GNU_PROPERTY_X86_FEATURE_1_SHSTK is set on interpreter.
> > a. If GNU_PROPERTY_X86_FEATURE_1_SHSTK isn't set on the executable
> > or any shared objects loaded via the DT_NEEDED tag, disable SHSTK.
> > b. Otherwise lock SHSTK.
> > 3. After SHSTK is enabled, it is an error to load a shared object
> > without GNU_PROPERTY_X86_FEATURE_1_SHSTK.
>
> OK.
>
> > To enable CET support in glibc, --enable-cet is required to configure
> > glibc. When CET is enabled, both compiler and assembler must support
> > CET. Otherwise, it is a configure-time error.
>
> OK. Good a configure-time error is best here.
>
> > To support CET run-time control,
> >
> > 1. _dl_x86_feature_1 is added to the writable ld.so namespace to indicate
> > if IBT or SHSTK are enabled at run-time. It should be initialized by
> > init_cpu_features.
>
> OK.
>
> > 2. For dynamic executables:
> > a. A l_cet field is added to struct link_map to indicate if IBT or
> > SHSTK is enabled in an ELF module. The optional DL_PROCESS_PT_NOTE
> > is called to process PT_NOTE segment for GNU program property and
> > set l_cet.
>
> OK.
>
> > b. _dl_start_user calls _dl_cet_init, instead of _dl_init, which sets
> > up IBT and SHSTK.
>
> OK.
>
> > c. DL_OPEN_CHECK is added to check IBT and SHSTK compatibilty when
> > dlopening a shared object.
>
> OK.
>
> > 3. Replace i386 _dl_runtime_resolve and _dl_runtime_profile with
> > _dl_runtime_resolve_shstk and _dl_runtime_profile_shstk, respectively if
> > SHSTK is enabled.
>
> OK.
>
> >
> > <cet.h> from CET-enabled GCC is automatically included by assembly codes
> > to add GNU_PROPERTY_X86_FEATURE_1_IBT and GNU_PROPERTY_X86_FEATURE_1_SHSTK
> > to GNU program property. _CET_ENDBR is added at the entrance of all
> > assembly functions whose address may be taken. _CET_NOTRACK is used to
> > insert NOTRACK prefix with indirect jump table to support IBT. It is
> > defined as notrack when _CET_NOTRACK is defined in <cet.h>.
> >
>
> OK.
>
> > diff --git a/configure.ac b/configure.ac
> > index ca1282a6b3..d342227f7a 100644
> > --- a/configure.ac
> > +++ b/configure.ac
> > @@ -453,6 +453,12 @@ AC_ARG_ENABLE([mathvec],
> > [build_mathvec=$enableval],
> > [build_mathvec=notset])
> >
> > +AC_ARG_ENABLE([cet],
> > + AC_HELP_STRING([--enable-cet],
> > + [enable Intel Control-flow Enforcement Technology (CET), x86 only]),
> > + [enable_cet=$enableval],
> > + [enable_cet=no])
>
> OK.
>
> > +
> > # We keep the original values in `$config_*' and never modify them, so we
> > # can write them unchanged into config.make. Everything else uses
> > # $machine, $vendor, and $os, and changes them whenever convenient.
> > diff --git a/elf/dl-load.c b/elf/dl-load.c
> > index e81601f36d..6197124d02 100644
> > --- a/elf/dl-load.c
> > +++ b/elf/dl-load.c
> > @@ -30,6 +30,32 @@
> > #include <sys/param.h>
> > #include <sys/stat.h>
> > #include <sys/types.h>
> > +
> > +/* Type for the buffer we put the ELF header and hopefully the program
> > + header. This buffer does not really have to be too large. In most
> > + cases the program header follows the ELF header directly. If this
> > + is not the case all bets are off and we can make the header
> > + arbitrarily large and still won't get it read. This means the only
> > + question is how large are the ELF and program header combined. The
> > + ELF header 32-bit files is 52 bytes long and in 64-bit files is 64
> > + bytes long. Each program header entry is again 32 and 56 bytes
> > + long respectively. I.e., even with a file which has 10 program
> > + header entries we only have to read 372B/624B respectively. Add to
> > + this a bit of margin for program notes and reading 512B and 832B
> > + for 32-bit and 64-bit files respecitvely is enough. If this
> > + heuristic should really fail for some file the code in
> > + `_dl_map_object_from_fd' knows how to recover. */
>
> OK.
>
> > -struct filebuf
> > -{
> > - ssize_t len;
> > -#if __WORDSIZE == 32
> > -# define FILEBUF_SIZE 512
> > -#else
> > -# define FILEBUF_SIZE 832
> > -#endif
> > - char buf[FILEBUF_SIZE] __attribute__ ((aligned (__alignof (ElfW(Ehdr)))));
> > -};
> > -
>
> OK.
>
> > /* This is the decomposed LD_LIBRARY_PATH search path. */
> > static struct r_search_path_struct env_path_list attribute_relro;
> >
> > @@ -1150,6 +1151,16 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
> > l->l_relro_addr = ph->p_vaddr;
> > l->l_relro_size = ph->p_memsz;
> > break;
> > +
> > +#ifdef DL_PROCESS_PT_NOTE
> > + case PT_NOTE:
> > + if (DL_PROCESS_PT_NOTE (l, ph, fd, fbp))
> > + {
> > + errstring = N_("cannot process note segment");
> > + goto call_lose;
> > + }
> > + break;
> > +#endif
>
> This is a typo-prone macro API. Please find a way for all arches to define
> a do-nothing version of this API.
>
> This seems like a sensible design. It's relatively cheap to walk the notes looking
> for the one of interest. I don't imagine we'll get millions of notes, and if we do then
> we'll have to do something else.
Fixed. Call _dl_process_pt_note unconditionally.
>
> > }
> >
> > if (__glibc_unlikely (nloadcmds == 0))
> > diff --git a/elf/dl-open.c b/elf/dl-open.c
> > index 9dde4acfbc..f3bc41cb47 100644
> > --- a/elf/dl-open.c
> > +++ b/elf/dl-open.c
> > @@ -291,6 +291,10 @@ dl_open_worker (void *a)
> > _dl_debug_state ();
> > LIBC_PROBE (map_complete, 3, args->nsid, r, new);
> >
> > +#ifdef DL_OPEN_CHECK
> > + DL_OPEN_CHECK (new);
> > +#endif
>
> This is a typo-prone macro API. Otherwise OK.
>
> Please find a way that we can define a generic version which is always used.
>
Fixed. Call _dl_open_check unconditionally.
> > +
> > /* Print scope information. */
> > if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_SCOPES))
> > _dl_show_scope (new, 0);
> > diff --git a/elf/rtld.c b/elf/rtld.c
> > index 8c732adb68..04b692908d 100644
> > --- a/elf/rtld.c
> > +++ b/elf/rtld.c
> > @@ -1241,6 +1241,14 @@ of this helper program; chances are you did not intend to run this program.\n\
> > main_map->l_relro_addr = ph->p_vaddr;
> > main_map->l_relro_size = ph->p_memsz;
> > break;
> > +
> > +#ifdef DL_PROCESS_PT_NOTE
> > + case PT_NOTE:
> > + if (DL_PROCESS_PT_NOTE (main_map, ph))
> > + _dl_error_printf ("\
> > +ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
> > + break;
> > +#endif
>
> This is a typo-prone macro API. Otherwise OK.
>
> Please find a way that we can define a generic version which is always used.
>
Fixed. Call _rtld_process_pt_note unconditionally.
> > }
> >
> > /* Adjust the address of the TLS initialization image in case
> > @@ -2110,6 +2118,10 @@ ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
> > _dl_show_scope (l, 0);
> > }
> >
> > +#ifdef DL_MAIN_CHECK
> > + DL_MAIN_CHECK (main_map, _dl_argv[0]);
> > +#endif
> > +
>
> This is a typo-prone macro API. Otherwise OK.
>
> Please find a way that we can define a generic version which is always used.
>
Fixed. Call _rtld_main_check unconditionally.
>
> > if (prelinked)
> > {
> > if (main_map->l_info [ADDRIDX (DT_GNU_CONFLICT)] != NULL)
> > diff --git a/sysdeps/i386/dl-trampoline.S b/sysdeps/i386/dl-trampoline.S
> > index 8bf86f8fd9..6dc0319216 100644
> > --- a/sysdeps/i386/dl-trampoline.S
> > +++ b/sysdeps/i386/dl-trampoline.S
> > @@ -32,6 +32,7 @@
> > .align 16
> > _dl_runtime_resolve:
> > cfi_adjust_cfa_offset (8)
> > + _CET_ENDBR
>
> OK.
>
> > + jmp *%ecx # Jump to function address.
> > + cfi_endproc
> > + .size _dl_runtime_resolve_shstk, .-_dl_runtime_resolve_shstk
>
> OK.
>
> >
> > + # Adjust stack: PLT1 + PLT2 + %esp + %ebp + %eax + %ecx + %edx
> > + # + free.
> > + addl $32, %esp
> > + cfi_adjust_cfa_offset (-32)
> > + jmp *%ecx # Jump to function address.
> > + cfi_endproc
> > + .size _dl_runtime_profile_shstk, .-_dl_runtime_profile_shstk
> > +
>
> OK.
>
> > .globl _dl_runtime_profile
> > .type _dl_runtime_profile, @function
> > cfi_startproc
> > .align 16
> > _dl_runtime_profile:
> > cfi_adjust_cfa_offset (8)
> > + _CET_ENDBR
>
> OK.
>
> > pushl %esp
> > cfi_adjust_cfa_offset (4)
> > addl $8, (%esp) # Account for the pushed PLT data
> > diff --git a/sysdeps/unix/sysv/linux/i386/dl-cet.c b/sysdeps/unix/sysv/linux/i386/dl-cet.c
> > new file mode 100644
> > index 0000000000..d9d80e151c
> > --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/i386/dl-cet.c
>
> If the trampoline is not linux-specific why is this?
Fixed.
> > + got = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
> > + if (got[2] == (Elf32_Addr) &_dl_runtime_resolve)
> > + got[2] = (Elf32_Addr) &_dl_runtime_resolve_shstk;
> > + else if (got[2] == (Elf32_Addr) &_dl_runtime_profile)
> > + got[2] = (Elf32_Addr) &_dl_runtime_profile_shstk;
> > + }
> > + }
> > + }
> > +}
>
> This looks suspiciously a lot like what we do in dl-machine.h for
> lazy setup. Is there any reason we can't put this code into the same
> macros we use in dl-machine.h?
>
> As I noted this code is in the linux-specific subdirectories, but doesn't
> seem to be linux specific?
>
Fixed. Renamed it to sysdeps/i386/dl-cet.c.
> > diff --git a/sysdeps/unix/sysv/linux/i386/dl-machine.h b/sysdeps/unix/sysv/linux/i386/dl-machine.h
> > new file mode 100644
> > index 0000000000..3c2894edf2
> > --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/i386/dl-machine.h
> > @@ -0,0 +1,23 @@
>
> Why not include dl-cet.h directly from the generic dl-machine.h?
>
> None of this support seems OS-specific. Other OSs could implement
> CET support.
Fixed. Removed.
>
> > diff --git a/sysdeps/unix/sysv/linux/x86/Makefile b/sysdeps/unix/sysv/linux/x86/Makefile
> > index 111ff9ff58..00be6cc472 100644
> > --- a/sysdeps/unix/sysv/linux/x86/Makefile
> > +++ b/sysdeps/unix/sysv/linux/x86/Makefile
> > @@ -23,3 +23,45 @@ endif
> > ifeq ($(subdir),setjmp)
> > tests += tst-saved_mask-1
> > endif
> > +
> > +ifeq ($(enable-cet),yes)
> > +ifeq ($(subdir),elf)
> > +sysdep-dl-routines += dl-cet
>
> OK.
>
> > +endif
> > +
> > +# Add -fcf-protection to CFLAGS when CET is enabled.
> > +CFLAGS-.o += -fcf-protection
> > +CFLAGS-.os += -fcf-protection
> > +CFLAGS-.op += -fcf-protection
> > +CFLAGS-.oS += -fcf-protection
>
> OK.
>
> > +
> > +# Compile assembly codes with <cet.h> when CET is enabled.
> > +asm-CPPFLAGS += -fcf-protection -include cet.h
> > +
> > +ifeq ($(subdir),elf)
> > +ifeq (yes,$(build-shared))
> > +tests-special += $(objpfx)check-cet.out
> > +endif
> > +
>
> OK.
>
> > +# FIXME: Can't use all-built-dso in elf/Makefile since this file is
> > +# processed before elf/Makefile. Duplicate it here.
>
> OK, this FIXME is valid, it's a failing of our current layout that you
> can't do what you want.
>
> Please add a comment in the *other* copy to reference that this copy
> needs to be updated also when there is a change.
Done.
>
> > +cet-built-dso := $(common-objpfx)elf/ld.so $(common-objpfx)libc.so \
> > + $(filter-out $(common-objpfx)linkobj/libc.so, \
> > + $(sort $(wildcard $(addprefix $(common-objpfx), \
> > + */lib*.so \
> > + iconvdata/*.so))))
>
> OK.
>
> > +
> > +$(cet-built-dso:=.note): %.note: %
> > + @rm -f $@T
> > + LC_ALL=C $(READELF) -n $< > $@T
> > + test -s $@T
> > + mv -f $@T $@
> > +common-generated += $(cet-built-dso:$(common-objpfx)%=%.note)
>
> OK.
>
> > +
> > +$(objpfx)check-cet.out: $(..)sysdeps/unix/sysv/linux/x86/check-cet.awk \
> > + $(cet-built-dso:=.note)
> > + LC_ALL=C $(AWK) -f $^ > $@; \
> > + $(evaluate-test)
> > +generated += check-cet.out
> > +endif
> > +endif
>
> OK.
>
> > diff --git a/sysdeps/unix/sysv/linux/x86/check-cet.awk b/sysdeps/unix/sysv/linux/x86/check-cet.awk
>
> OK.
> > +++ b/sysdeps/unix/sysv/linux/x86/configure.ac
>
> Is this really linux-specific?
No.
> > +fi
>
> OK.
>
> > +if test $enable_cet = yes; then
> > + # Check if assembler supports CET.
> > + AC_CACHE_CHECK(whether $AS supports CET,
> > + libc_cv_x86_cet_as, [dnl
> > +cat > conftest.s <<EOF
> > + incsspd %ecx
> > +EOF
> > + if AC_TRY_COMMAND(${CC-cc} -c $CFLAGS conftest.s -o conftest.o 1>&AS_MESSAGE_LOG_FD); then
> > + libc_cv_x86_cet_as=yes
> > + else
> > + libc_cv_x86_cet_as=no
> > + fi
> > + rm -rf conftest*])
> > + if test $libc_cv_x86_cet_as = no; then
> > + AC_MSG_ERROR([$AS doesn't support CET])
> > + fi
> > +fi
> > +LIBC_CONFIG_VAR([enable-cet], [$enable_cet])
>
> It looks like all of this could run generically for CET support.
I moved the whole CET check to the sysdeps/x86 directory.
> > +
> > +#include <unistd.h>
> > +#include <errno.h>
> > +#include <libintl.h>
> > +#include <ldsodefs.h>
> > +
> > +static int
> > +dl_cet_mark_legacy_region (struct link_map *l)
> > +{
> > + /* FIXME: Mark legacy region */
> > + return 0;
>
> Why is there a FIXME here?
>
Fixed.
> This patch should be complete or it should be an RFC.
>
> If it is complete it should explain why no action needs to be taken in
> the OS to mark legacy regions.
I moved the CET support to the sysdeps/x86 directory.
>
> > +}
> > +
> > +/* Check if object M is compatible with CET. */
> > +
> > +static void
> > +dl_cet_check (struct link_map *m, const char *program)
> > +{
> > + /* Check if IBT is enabled by kernel. */
> > + bool ibt_enabled
> > + = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0;
> > + /* Check if SHSTK is enabled by kernel. */
> > + bool shstk_enabled
> > + = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0;
> > +
>
> OK.
>
> > + if (ibt_enabled || shstk_enabled)
> > + {
> > + struct link_map *l = NULL;
> > +
> > + /* Check if IBT and SHSTK are enabled in object. */
> > + bool enable_ibt = ibt_enabled;
> > + bool enable_shstk = shstk_enabled;
> > + if (program)
> > + {
> > + /* Enable IBT and SHSTK only if they are enabled in executable.
> > + NB: IBT and SHSTK may be disabled by environment variable:
> > +
> > + GLIBC_TUNABLES=glibc.tune.hwcaps=-IBT,-SHSTK
> > + */
> > + enable_ibt &= (HAS_CPU_FEATURE (IBT)
> > + && (m->l_cet & lc_ibt) != 0);
> > + enable_shstk &= (HAS_CPU_FEATURE (SHSTK)
> > + && (m->l_cet & lc_shstk) != 0);
>
> OK.
>
> > + }
> > +
> > + /* ld.so is CET-enabled by kernel. But shared objects may not
> > + support IBT nor SHSTK. */
> > + if (enable_ibt || enable_shstk)
> > + {
> > + int res;
> > + unsigned int i;
> > + unsigned int first_legacy, last_legacy;
> > + bool need_legacy_bitmap = false;
> > +
> > + i = m->l_searchlist.r_nlist;
> > + while (i-- > 0)
> > + {
> > + /* Check each shared object to see if IBT and SHSTK are
> > + enabled. */
> > + l = m->l_initfini[i];
> > +
> > + if (l->l_init_called)
> > + continue;
> > +
> > +#ifdef SHARED
> > + /* Skip CET check for ld.so since ld.so is CET-enabled.
> > + CET will be disabled later if CET isn't enabled in
> > + executable. */
>
> OK.
>
> > + if (l == &GL(dl_rtld_map)
> > + || l->l_real == &GL(dl_rtld_map)
> > + || (program && l == m))
> > + continue;
> > +#endif
> > +
> > + if (enable_ibt && !(l->l_cet & lc_ibt))
> > + {
> > + /* Remember the first and last legacy objects. */
> > + if (!need_legacy_bitmap)
> > + last_legacy = i;
> > + first_legacy = i;
> > + need_legacy_bitmap = true;
> > + }
> > +
> > + /* SHSTK is enabled only if it is enabled in executable as
> > + well as all shared objects. */
> > + enable_shstk &= (l->l_cet & lc_shstk) != 0;
> > + }
> > +
> > + if (need_legacy_bitmap)
> > + {
> > + /* Put legacy shared objects in legacy bitmap. */
> > + for (i = first_legacy; i <= last_legacy; i++)
> > + {
> > + l = m->l_initfini[i];
> > +
> > + if (l->l_init_called || (l->l_cet & lc_ibt))
> > + continue;
> > +
> > +#ifdef SHARED
> > + if (l == &GL(dl_rtld_map)
> > + || l->l_real == &GL(dl_rtld_map)
> > + || (program && l == m))
> > + continue;
> > +#endif
> > +
> > + /* If IBT is enabled in executable and IBT isn't enabled
> > + in this shard object, mark PT_LOAD segments with PF_X
> > + in legacy code page bitmap. */
> > + res = dl_cet_mark_legacy_region (l);
>
> ... which does nothing? Is the kernel side of the requirements not known yet?
>
> > + if (res != 0)
> > + {
> > + if (program)
> > + _dl_fatal_printf ("%s: fail to mark legacy code region\n",
> > + l->l_name);
> > + else
> > + _dl_signal_error (-res, l->l_name, "dlopen",
> > + N_("fail to mark legacy code region"));
> > + }
> > + }
> > + }
> > + }
> > +
> > + if (enable_ibt != ibt_enabled || enable_shstk != shstk_enabled)
> > + {
> > + if (!program)
> > + {
> > + /* When SHSTK is enabled, we can't dlopening a shared
> > + object without SHSTK. */
> > + if (enable_shstk != shstk_enabled)
> > + _dl_signal_error (EINVAL, l->l_name, "dlopen",
> > + N_("shadow stack isn't enabled"));
>
> OK.
>
> > + return;
> > + }
> > +
> > +#ifdef SHARED
> > + /* FIXME: Disable IBT and/or SHSTK if they are enabled in
> > + ld.so, but disabled in executable or shared objects. */
> > + ;
>
> Is the code missing?
Fixed.
>
> > +#endif
> > + }
> > +
> > +#ifdef SHARED
> > + if (program && (ibt_enabled || shstk_enabled))
> > + {
> > + /* FIXME: Lock CET if IBT or SHSTK is enabled in executable. */
> > + ;
>
>
> Similarly?
Fixed.
>
> > + }
> > +#endif
> > + }
> > +}
> > +
> > +void
> > +_dl_cet_open_check (struct link_map *l)
> > +{
> > + dl_cet_check (l, NULL);
> > +}
>
> OK.
>
> > +
> > +#ifdef SHARED
> > +
> > +# ifndef LINKAGE
> > +# define LINKAGE
> > +# endif
> > +
> > +LINKAGE
> > +void
> > +_dl_cet_check (struct link_map *main_map, const char *program)
> > +{
> > + dl_cet_check (main_map, program);
> > +}
> > +#endif /* SHARED */
>
> OK.
>
> > + attribute_hidden;
>
> OK.
>
> > +
> > +#define DL_MAIN_CHECK(l, n) _dl_cet_check ((l), (n))
>
> You have to find a way to define this everywhere.
Fixed.
>
> > +static inline void __attribute__ ((unused))
> > +dl_process_cet_property_note (struct link_map *l,
> > + const ElfW(Nhdr) *note,
> > + const ElfW(Addr) size,
> > + const ElfW(Addr) align)
> > +{
> > + /* The NT_GNU_PROPERTY_TYPE_0 note must be aliged to 4 bytes in
> > + 32-bit objects and to 8 bytes in 64-bit objects. Skip notes
> > + with incorrect alignment. */
> > + if (align != (__ELF_NATIVE_CLASS / 8))
> > + return;
> > +
> > + const ElfW(Addr) start = (ElfW(Addr)) note;
> > +
> > + while ((ElfW(Addr)) (note + 1) - start < size)
>
> OK.
>
> > + {
> > + /* Find the NT_GNU_PROPERTY_TYPE_0 note. */
> > + if (note->n_namesz == 4
> > + && note->n_type == NT_GNU_PROPERTY_TYPE_0
> > + && memcmp (note + 1, "GNU", 4) == 0)
>
> OK.
>
> > + {
> > + /* Check for invalid property. */
> > + if (note->n_descsz < 8
> > + || (note->n_descsz % sizeof (ElfW(Addr))) != 0)
> > + break;
> > +
> > + /* Start and end of property array. */
> > + unsigned char *ptr = (unsigned char *) (note + 1) + 4;
> > + unsigned char *ptr_end = ptr + note->n_descsz;
> > +
> > + while (1)
> > + {
> > + unsigned int type = *(unsigned int *) ptr;
> > + unsigned int datasz = *(unsigned int *) (ptr + 4);
> > +
> > + ptr += 8;
> > + if ((ptr + datasz) > ptr_end)
> > + break;
> > +
> > + if (type == GNU_PROPERTY_X86_FEATURE_1_AND
> > + && datasz == 4)
> > + {
> > + unsigned int feature_1 = *(unsigned int *) ptr;
> > + if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_IBT))
> > + l->l_cet |= lc_ibt;
> > + if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_SHSTK))
> > + l->l_cet |= lc_shstk;
> > + break;
> > + }
>
> OK.
>
> > + }
> > + }
> > +
> > + /* NB: Note sections like .note.ABI-tag and .note.gnu.build-id are
> > + aligned to 4 bytes in 64-bit ELF objects. */
>
> OK.
>
> > + note = ((const void *) note
> > + + ELF_NOTE_NEXT_OFFSET (note->n_namesz, note->n_descsz,
> > + align));
> > + }
> > +}
> > +
> > +# ifdef FILEBUF_SIZE
> > +# define DL_PROCESS_PT_NOTE(l, ph, fd, fbp) \
> > + dl_process_pt_note ((l), (ph), (fd), (fbp))
>
> You need to find a way to define this for all arches.
>
> I suggest picking an existing header if you can find one, or a new one e.g. dl-check.h.
>
> You may want to clean that up first, for example:
>
> * We have DL_SYSDEP_OSCHECK
> * With header dl-osinfo.h
>
> You could put things in there for general undefined functions.
>
> Then in x86 you include dl-cet.h into dl-osinfo.h.
>
> Then it's really Linux-specific.
Fixed. I added dl-prop.h, which is only used in 3 files.
>
> > +
> > +static inline int __attribute__ ((unused))
> > +dl_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph,
> > + int fd, struct filebuf *fbp)
> > +{
> > + const ElfW(Nhdr) *note;
> > + ElfW(Nhdr) *note_malloced = NULL;
> > + ElfW(Addr) size = ph->p_filesz;
> > +
> > + if (ph->p_offset + size <= (size_t) fbp->len)
> > + note = (const void *) (fbp->buf + ph->p_offset);
> > + else
> > + {
> > + if (size < __MAX_ALLOCA_CUTOFF)
> > + note = alloca (size);
> > + else
> > + {
> > + note_malloced = malloc (size);
> > + note = note_malloced;
> > + }
> > + __lseek (fd, ph->p_offset, SEEK_SET);
> > + if (__libc_read (fd, (void *) note, size) != size)
> > + {
> > + if (note_malloced)
> > + free (note_malloced);
> > + return -1;
> > + }
> > + }
>
> OK.
>
> > +
> > + dl_process_cet_property_note (l, note, size, ph->p_align);
> > + if (note_malloced)
> > + free (note_malloced);
> > + return 0;
> > +}
> > +# else
> > +# define DL_PROCESS_PT_NOTE(l, ph) dl_process_pt_note ((l), (ph))
>
> OK.
>
> > +
> > +static inline int __attribute__ ((unused))
> > +dl_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph)
> > +{
> > + const ElfW(Nhdr) *note = (const void *) (ph->p_vaddr + l->l_addr);
> > + dl_process_cet_property_note (l, note, ph->p_memsz, ph->p_align);
> > + return 0;
> > +}
>
> OK.
>
> > +
> > +#ifndef PROCINFO_CLASS
> > +# define PROCINFO_CLASS
> > +#endif
> > +
> > +#if !IS_IN (ldconfig)
> > +# if !defined PROCINFO_DECL && defined SHARED
> > + ._dl_x86_feature_1
> > +# else
> > +PROCINFO_CLASS unsigned int _dl_x86_feature_1[2]
> > +# endif
> > +# if !defined SHARED || defined PROCINFO_DECL
> > +;
> > +# else
> > +,
> > +# endif
> > +#endif
>
> OK.
>
> > diff --git a/sysdeps/unix/sysv/linux/x86/ldsodefs.h b/sysdeps/unix/sysv/linux/x86/ldsodefs.h
> > new file mode 100644
> > index 0000000000..bf8954b045
> > --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/x86/ldsodefs.h
> > +
> > +#ifdef __CET__
> > +extern void _dl_cet_open_check (struct link_map *);
> > +# define DL_OPEN_CHECK(l) _dl_cet_open_check ((l))
> > +#endif
> > +
>
> OK. Though as I note you need to find a way to always define DL_OPEN_CHECK.
>
Fixed.
> > diff --git a/sysdeps/unix/sysv/linux/x86/link_map.h b/sysdeps/unix/sysv/linux/x86/link_map.h
> > new file mode 100644
> > index 0000000000..ef1206a9d2
> > --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/x86/link_map.h
> > + lc_ibt_and_shstk = lc_ibt | lc_shstk /* Enabled with both. */
> > + } l_cet:2;
>
> OK.
>
> > diff --git a/sysdeps/unix/sysv/linux/x86_64/dl-machine.h b/sysdeps/unix/sysv/linux/x86_64/dl-machine.h
> > +
> > +#ifdef __CET__
> > +# include <sysdeps/unix/sysv/linux/x86/dl-cet.h>
> > +#endif
> > +#ifdef __ILP32__
> > +# include <sysdeps/x86_64/x32/dl-machine.h>
> > +#else
> > +# include <sysdeps/x86_64/dl-machine.h>
> > +#endif
>
> Why do this and not just directly include dl-cet.h into the existing
> non-Linux dl-machine?
>
> CET is not Linux-specific it's a piece of hardware technology?
Fixed. dl-cet.h now only provides inlined CET syscalls.
>
> > diff --git a/sysdeps/x86/cpu-features.h b/sysdeps/x86/cpu-features.h
> > index 624e681e96..4e15c15e92 100644
> > --- a/sysdeps/x86/cpu-features.h
> > +++ b/sysdeps/x86/cpu-features.h
> > @@ -160,6 +160,11 @@ struct cpu_features
> > extern const struct cpu_features *__get_cpu_features (void)
> > __attribute__ ((const));
> >
> > +# ifdef ElfW
> > +extern void _dl_setup_cet (const ElfW(Phdr) *, size_t, const ElfW(Addr))
> > + attribute_hidden;
> > +# endif
>
> OK.
>
> > +
> > # if defined (_LIBC) && !IS_IN (nonlib)
> > /* Unused for x86. */
> > # define INIT_ARCH()
> > diff --git a/sysdeps/x86/sysdep.h b/sysdeps/x86/sysdep.h
> > index afcb7cfd76..9843d9dff7 100644
> > --- a/sysdeps/x86/sysdep.h
> > +++ b/sysdeps/x86/sysdep.h
> > @@ -25,6 +25,13 @@
> >
> > /* Syntactic details of assembler. */
> >
> > +#ifdef _CET_ENDBR
> > +# define _CET_NOTRACK notrack
> > +#else
> > +# define _CET_ENDBR
> > +# define _CET_NOTRACK
> > +#endif
>
> OK.
>
> > +
> > /* ELF uses byte-counts for .align, most others use log2 of count of bytes. */
> > #define ALIGNARG(log2) 1<<log2
> > #define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
> > @@ -36,6 +43,7 @@
> > .align ALIGNARG(4); \
> > C_LABEL(name) \
> > cfi_startproc;
>
> OK.
> \
> > + _CET_ENDBR; \
> > CALL_MCOUNT
> >
> > #undef END
> > diff --git a/sysdeps/x86_64/dl-trampoline.h b/sysdeps/x86_64/dl-trampoline.h
> > index 298cfb3d99..a28b1e73a4 100644
> > --- a/sysdeps/x86_64/dl-trampoline.h
> > +++ b/sysdeps/x86_64/dl-trampoline.h
> > @@ -64,6 +64,7 @@
> > cfi_startproc
> > _dl_runtime_resolve:
> > cfi_adjust_cfa_offset(16) # Incorporate PLT
> > + _CET_ENDBR
>
> OK.
>
> > # if DL_RUNTIME_RESOLVE_REALIGN_STACK
> > # if LOCAL_STORAGE_AREA != 8
> > # error LOCAL_STORAGE_AREA must be 8
> > @@ -168,6 +169,7 @@ _dl_runtime_resolve:
> > _dl_runtime_profile:
> > cfi_startproc
> > cfi_adjust_cfa_offset(16) # Incorporate PLT
> > + _CET_ENDBR
>
> OK.
>
> > /* The La_x86_64_regs data structure pointed to by the
> > fourth paramater must be VEC_SIZE-byte aligned. This must
> > be explicitly enforced. We have the set up a dynamically
> >
>
Here is the V2 patch.
H.J.
---
From 722b5907c808efdf051d7a2441a390836b2d5aef Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Thu, 22 Jun 2017 04:15:39 -0700
Subject: [PATCH 03/24] x86: Support IBT and SHSTK in Intel CET [BZ #21598]
Intel Control-flow Enforcement Technology (CET) instructions:
https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-en
forcement-technology-preview.pdf
includes Indirect Branch Tracking (IBT) and Shadow Stack (SHSTK).
GNU_PROPERTY_X86_FEATURE_1_IBT is added to GNU program property to
indicate that all executable sections are compatible with IBT when
ENDBR instruction starts each valid target where an indirect branch
instruction can land. Linker sets GNU_PROPERTY_X86_FEATURE_1_IBT on
output only if it is set on all relocatable inputs.
On an IBT capable processor, the following steps should be taken:
1. When loading an executable without an interpreter, enable IBT and
lock IBT if GNU_PROPERTY_X86_FEATURE_1_IBT is set on the executable.
2. When loading an executable with an interpreter, enable IBT if
GNU_PROPERTY_X86_FEATURE_1_IBT is set on the interpreter.
a. If GNU_PROPERTY_X86_FEATURE_1_IBT isn't set on the executable,
disable IBT.
b. Lock IBT.
3. If IBT is enabled, when loading a shared object without
GNU_PROPERTY_X86_FEATURE_1_IBT:
a. If legacy interwork is allowed, then mark all pages in executable
PT_LOAD segments in legacy code page bitmap. Failure of legacy code
page bitmap allocation causes an error.
b. If legacy interwork isn't allowed, it causes an error.
GNU_PROPERTY_X86_FEATURE_1_SHSTK is added to GNU program property to
indicate that all executable sections are compatible with SHSTK where
return address popped from shadow stack always matches return address
popped from normal stack. Linker sets GNU_PROPERTY_X86_FEATURE_1_SHSTK
on output only if it is set on all relocatable inputs.
On a SHSTK capable processor, the following steps should be taken:
1. When loading an executable without an interpreter, enable SHSTK if
GNU_PROPERTY_X86_FEATURE_1_SHSTK is set on the executable.
2. When loading an executable with an interpreter, enable SHSTK if
GNU_PROPERTY_X86_FEATURE_1_SHSTK is set on interpreter.
a. If GNU_PROPERTY_X86_FEATURE_1_SHSTK isn't set on the executable
or any shared objects loaded via the DT_NEEDED tag, disable SHSTK.
b. Otherwise lock SHSTK.
3. After SHSTK is enabled, it is an error to load a shared object
without GNU_PROPERTY_X86_FEATURE_1_SHSTK.
To enable CET support in glibc, --enable-cet is required to configure
glibc. When CET is enabled, both compiler and assembler must support
CET. Otherwise, it is a configure-time error.
To support CET run-time control,
1. _dl_x86_feature_1 is added to the writable ld.so namespace to indicate
if IBT or SHSTK are enabled at run-time. It should be initialized by
init_cpu_features.
2. For dynamic executables:
a. A l_cet field is added to struct link_map to indicate if IBT or
SHSTK is enabled in an ELF module. _dl_process_pt_note or
_rtld_process_pt_note is called to process PT_NOTE segment for
GNU program property and set l_cet.
b. _dl_open_check is added to check IBT and SHSTK compatibilty when
dlopening a shared object.
3. Replace i386 _dl_runtime_resolve and _dl_runtime_profile with
_dl_runtime_resolve_shstk and _dl_runtime_profile_shstk, respectively if
SHSTK is enabled.
CET run-time control can be changed via GLIBC_TUNABLES with
$ export GLIBC_TUNABLES=glibc.tune.x86_shstk=[permissive|on|off]
$ export GLIBC_TUNABLES=glibc.tune.x86_ibt=[permissive|on|off]
1. permissive: SHSTK is disabled when dlopening a legacy ELF module.
2. on: IBT or SHSTK are always enabled, regardless if there are IBT or
SHSTK bits in GNU program property.
3. off: IBT or SHSTK are always disabled, regardless if there are IBT or
SHSTK bits in GNU program property.
<cet.h> from CET-enabled GCC is automatically included by assembly codes
to add GNU_PROPERTY_X86_FEATURE_1_IBT and GNU_PROPERTY_X86_FEATURE_1_SHSTK
to GNU program property. _CET_ENDBR is added at the entrance of all
assembly functions whose address may be taken. _CET_NOTRACK is used to
insert NOTRACK prefix with indirect jump table to support IBT. It is
defined as notrack when _CET_NOTRACK is defined in <cet.h>.
[BZ #21598]
* configure.ac: Add --enable-cet.
* configure: Regenerated.
* elf/Makefille (all-built-dso): Add a comment.
* elf/dl-load.c (filebuf): Moved before "dynamic-link.h".
Include <dl-prop.h>.
(_dl_map_object_from_fd): Call _dl_process_pt_note on PT_NOTE
segment.
* elf/dl-open.c: Include <dl-prop.h>.
(dl_open_worker): Call _dl_open_check.
* elf/rtld.c: Include <dl-prop.h>.
(dl_main): Call _rtld_process_pt_note on PT_NOTE segment. Call
_rtld_main_check.
* sysdeps/generic/dl-prop.h: New file.
* sysdeps/i386/dl-cet.c: Likewise.
* sysdeps/unix/sysv/linux/x86/cpu-features.c: Likewise.
* sysdeps/unix/sysv/linux/x86/dl-cet.h: Likewise.
* sysdeps/x86/cet-tunables.h: Likewise.
* sysdeps/x86/check-cet.awk: Likewise.
* sysdeps/x86/configure: Likewise.
* sysdeps/x86/configure.ac: Likewise.
* sysdeps/x86/dl-cet.c: Likewise.
* sysdeps/x86/dl-procruntime.c: Likewise.
* sysdeps/x86/dl-prop.h: Likewise.
* sysdeps/x86/libc-start.h: Likewise.
* sysdeps/x86/link_map.h: Likewise.
* sysdeps/i386/dl-trampoline.S (_dl_runtime_resolve): Add
_CET_ENDBR.
(_dl_runtime_profile): Likewise.
(_dl_runtime_resolve_shstk): New.
(_dl_runtime_profile_shstk): Likewise.
* sysdeps/linux/x86/Makefile (sysdep-dl-routines): Add dl-cet
if CET is enabled.
(CFLAGS-.o): Add -fcf-protection if CET is enabled.
(CFLAGS-.os): Likewise.
(CFLAGS-.op): Likewise.
(CFLAGS-.oS): Likewise.
(asm-CPPFLAGS): Add -fcf-protection -include cet.h if CET
is enabled.
(tests-special): Add $(objpfx)check-cet.out.
(cet-built-dso): New.
(+$(cet-built-dso:=.note)): Likewise.
(common-generated): Add $(cet-built-dso:$(common-objpfx)%=%.note).
($(objpfx)check-cet.out): New.
(generated): Add check-cet.out.
* sysdeps/x86/cpu-features.c: Include <dl-cet.h> and
<cet-tunables.h>.
(TUNABLE_CALLBACK (set_x86_ibt)): New prototype.
(TUNABLE_CALLBACK (set_x86_shstk)): Likewise.
(init_cpu_features): Call get_cet_status to check CET status
and update dl_x86_feature_1 with CET status. Call
TUNABLE_CALLBACK (set_x86_ibt) and TUNABLE_CALLBACK
(set_x86_shstk). Disable and lock CET in libc.a.
* sysdeps/x86/cpu-tunables.c: Include <cet-tunables.h>.
(TUNABLE_CALLBACK (set_x86_ibt)): New function.
(TUNABLE_CALLBACK (set_x86_shstk)): Likewise.
* sysdeps/x86/sysdep.h (_CET_NOTRACK): New.
(_CET_ENDBR): Define if not defined.
(ENTRY): Add _CET_ENDBR.
* sysdeps/x86/dl-tunables.list (glibc.tune): Add x86_ibt and
x86_shstk.
* sysdeps/x86_64/dl-trampoline.h (_dl_runtime_resolve): Add
_CET_ENDBR.
(_dl_runtime_profile): Likewise.
---
configure | 11 +
configure.ac | 6 +
elf/Makefile | 2 +
elf/dl-load.c | 60 ++--
elf/dl-open.c | 3 +
elf/rtld.c | 9 +
sysdeps/generic/dl-prop.h | 47 +++
sysdeps/i386/dl-cet.c | 67 +++++
sysdeps/i386/dl-trampoline.S | 72 +++++
sysdeps/unix/sysv/linux/x86/cpu-features.c | 38 +++
sysdeps/unix/sysv/linux/x86/dl-cet.h | 34 +++
sysdeps/x86/Makefile | 42 +++
sysdeps/x86/cet-tunables.h | 29 ++
sysdeps/x86/check-cet.awk | 53 ++++
sysdeps/x86/configure | 69 +++++
sysdeps/x86/configure.ac | 46 +++
sysdeps/x86/cpu-features.c | 65 ++++
sysdeps/x86/cpu-tunables.c | 48 +++
sysdeps/x86/dl-cet.c | 335 +++++++++++++++++++++
sysdeps/x86/dl-procruntime.c | 68 +++++
sysdeps/x86/dl-prop.h | 153 ++++++++++
sysdeps/x86/dl-tunables.list | 6 +
sysdeps/x86/libc-start.h | 25 ++
sysdeps/x86/link_map.h | 26 ++
sysdeps/x86/sysdep.h | 8 +
sysdeps/x86_64/dl-trampoline.h | 2 +
26 files changed, 1299 insertions(+), 25 deletions(-)
create mode 100644 sysdeps/generic/dl-prop.h
create mode 100644 sysdeps/i386/dl-cet.c
create mode 100644 sysdeps/unix/sysv/linux/x86/cpu-features.c
create mode 100644 sysdeps/unix/sysv/linux/x86/dl-cet.h
create mode 100644 sysdeps/x86/cet-tunables.h
create mode 100644 sysdeps/x86/check-cet.awk
create mode 100644 sysdeps/x86/configure
create mode 100644 sysdeps/x86/configure.ac
create mode 100644 sysdeps/x86/dl-cet.c
create mode 100644 sysdeps/x86/dl-procruntime.c
create mode 100644 sysdeps/x86/dl-prop.h
create mode 100644 sysdeps/x86/libc-start.h
create mode 100644 sysdeps/x86/link_map.h
diff --git a/configure b/configure
index eac7f292b4..fde57d63fe 100755
--- a/configure
+++ b/configure
@@ -790,6 +790,7 @@ enable_nscd
enable_pt_chown
enable_tunables
enable_mathvec
+enable_cet
with_cpu
'
ac_precious_vars='build_alias
@@ -1465,6 +1466,8 @@ Optional Features:
'no' and 'valstring'
--enable-mathvec Enable building and installing mathvec [default
depends on architecture]
+ --enable-cet enable Intel Control-flow Enforcement Technology
+ (CET), x86 only
Optional Packages:
--with-PACKAGE[=ARG] use PACKAGE [ARG=yes]
@@ -3759,6 +3762,14 @@ else
fi
+# Check whether --enable-cet was given.
+if test "${enable_cet+set}" = set; then :
+ enableval=$enable_cet; enable_cet=$enableval
+else
+ enable_cet=no
+fi
+
+
# We keep the original values in `$config_*' and never modify them, so we
# can write them unchanged into config.make. Everything else uses
# $machine, $vendor, and $os, and changes them whenever convenient.
diff --git a/configure.ac b/configure.ac
index f41ed6decb..014e09a5d5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -464,6 +464,12 @@ AC_ARG_ENABLE([mathvec],
[build_mathvec=$enableval],
[build_mathvec=notset])
+AC_ARG_ENABLE([cet],
+ AC_HELP_STRING([--enable-cet],
+ [enable Intel Control-flow Enforcement Technology (CET), x86 only]),
+ [enable_cet=$enableval],
+ [enable_cet=no])
+
# We keep the original values in `$config_*' and never modify them, so we
# can write them unchanged into config.make. Everything else uses
# $machine, $vendor, and $os, and changes them whenever convenient.
diff --git a/elf/Makefile b/elf/Makefile
index 41cc3681be..84107f6dbb 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -1058,6 +1058,8 @@ $(objpfx)tst-piemod1.so: $(libsupport)
$(objpfx)tst-pie1: $(objpfx)tst-piemod1.so
ifeq (yes,$(build-shared))
+# NB: Please keep cet-built-dso in sysdeps/x86/Makefile in sync with
+# all-built-dso here.
all-built-dso := $(common-objpfx)elf/ld.so $(common-objpfx)libc.so \
$(filter-out $(common-objpfx)linkobj/libc.so, \
$(sort $(wildcard $(addprefix $(common-objpfx), \
diff --git a/elf/dl-load.c b/elf/dl-load.c
index 09185ab68d..c51e4b3718 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -30,6 +30,32 @@
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/types.h>
+
+/* Type for the buffer we put the ELF header and hopefully the program
+ header. This buffer does not really have to be too large. In most
+ cases the program header follows the ELF header directly. If this
+ is not the case all bets are off and we can make the header
+ arbitrarily large and still won't get it read. This means the only
+ question is how large are the ELF and program header combined. The
+ ELF header 32-bit files is 52 bytes long and in 64-bit files is 64
+ bytes long. Each program header entry is again 32 and 56 bytes
+ long respectively. I.e., even with a file which has 10 program
+ header entries we only have to read 372B/624B respectively. Add to
+ this a bit of margin for program notes and reading 512B and 832B
+ for 32-bit and 64-bit files respecitvely is enough. If this
+ heuristic should really fail for some file the code in
+ `_dl_map_object_from_fd' knows how to recover. */
+struct filebuf
+{
+ ssize_t len;
+#if __WORDSIZE == 32
+# define FILEBUF_SIZE 512
+#else
+# define FILEBUF_SIZE 832
+#endif
+ char buf[FILEBUF_SIZE] __attribute__ ((aligned (__alignof (ElfW(Ehdr)))));
+};
+
#include "dynamic-link.h"
#include <abi-tag.h>
#include <stackinfo.h>
@@ -44,6 +70,7 @@
#include <dl-unmap-segments.h>
#include <dl-machine-reject-phdr.h>
#include <dl-sysdep-open.h>
+#include <dl-prop.h>
#include <not-cancel.h>
#include <endian.h>
@@ -69,31 +96,6 @@ int __stack_prot attribute_hidden attribute_relro
#endif
-/* Type for the buffer we put the ELF header and hopefully the program
- header. This buffer does not really have to be too large. In most
- cases the program header follows the ELF header directly. If this
- is not the case all bets are off and we can make the header
- arbitrarily large and still won't get it read. This means the only
- question is how large are the ELF and program header combined. The
- ELF header 32-bit files is 52 bytes long and in 64-bit files is 64
- bytes long. Each program header entry is again 32 and 56 bytes
- long respectively. I.e., even with a file which has 10 program
- header entries we only have to read 372B/624B respectively. Add to
- this a bit of margin for program notes and reading 512B and 832B
- for 32-bit and 64-bit files respecitvely is enough. If this
- heuristic should really fail for some file the code in
- `_dl_map_object_from_fd' knows how to recover. */
-struct filebuf
-{
- ssize_t len;
-#if __WORDSIZE == 32
-# define FILEBUF_SIZE 512
-#else
-# define FILEBUF_SIZE 832
-#endif
- char buf[FILEBUF_SIZE] __attribute__ ((aligned (__alignof (ElfW(Ehdr)))));
-};
-
/* This is the decomposed LD_LIBRARY_PATH search path. */
static struct r_search_path_struct env_path_list attribute_relro;
@@ -1152,6 +1154,14 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
l->l_relro_addr = ph->p_vaddr;
l->l_relro_size = ph->p_memsz;
break;
+
+ case PT_NOTE:
+ if (_dl_process_pt_note (l, ph, fd, fbp))
+ {
+ errstring = N_("cannot process note segment");
+ goto call_lose;
+ }
+ break;
}
if (__glibc_unlikely (nloadcmds == 0))
diff --git a/elf/dl-open.c b/elf/dl-open.c
index 9dde4acfbc..f6c8ef1043 100644
--- a/elf/dl-open.c
+++ b/elf/dl-open.c
@@ -35,6 +35,7 @@
#include <libc-internal.h>
#include <dl-dst.h>
+#include <dl-prop.h>
/* We must be careful not to leave us in an inconsistent state. Thus we
@@ -291,6 +292,8 @@ dl_open_worker (void *a)
_dl_debug_state ();
LIBC_PROBE (map_complete, 3, args->nsid, r, new);
+ _dl_open_check (new);
+
/* Print scope information. */
if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_SCOPES))
_dl_show_scope (new, 0);
diff --git a/elf/rtld.c b/elf/rtld.c
index 8c732adb68..1b0c74739f 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -38,6 +38,7 @@
#include <dl-cache.h>
#include <dl-osinfo.h>
#include <dl-procinfo.h>
+#include <dl-prop.h>
#include <tls.h>
#include <stap-probe.h>
#include <stackinfo.h>
@@ -1241,6 +1242,12 @@ of this helper program; chances are you did not intend to run this program.\n\
main_map->l_relro_addr = ph->p_vaddr;
main_map->l_relro_size = ph->p_memsz;
break;
+
+ case PT_NOTE:
+ if (_rtld_process_pt_note (main_map, ph))
+ _dl_error_printf ("\
+ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
+ break;
}
/* Adjust the address of the TLS initialization image in case
@@ -2110,6 +2117,8 @@ ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
_dl_show_scope (l, 0);
}
+ _rtld_main_check (main_map, _dl_argv[0]);
+
if (prelinked)
{
if (main_map->l_info [ADDRIDX (DT_GNU_CONFLICT)] != NULL)
diff --git a/sysdeps/generic/dl-prop.h b/sysdeps/generic/dl-prop.h
new file mode 100644
index 0000000000..e5fe5d23aa
--- /dev/null
+++ b/sysdeps/generic/dl-prop.h
@@ -0,0 +1,47 @@
+/* Support for GNU properties. Generic version.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef _DL_PROP_H
+#define _DL_PROP_H
+
+static inline void __attribute__ ((always_inline))
+_rtld_main_check (struct link_map *m, const char *program)
+{
+}
+
+static inline void __attribute__ ((always_inline))
+_dl_open_check (struct link_map *m)
+{
+}
+
+#ifdef FILEBUF_SIZE
+static inline int __attribute__ ((always_inline))
+_dl_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph,
+ int fd, struct filebuf *fbp)
+{
+ return 0;
+}
+#endif
+
+static inline int __attribute__ ((always_inline))
+_rtld_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph)
+{
+ return 0;
+}
+
+#endif /* _DL_PROP_H */
diff --git a/sysdeps/i386/dl-cet.c b/sysdeps/i386/dl-cet.c
new file mode 100644
index 0000000000..5d9a4e8d51
--- /dev/null
+++ b/sysdeps/i386/dl-cet.c
@@ -0,0 +1,67 @@
+/* Linux/i386 CET initializers function.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+
+#define LINKAGE static inline
+#define _dl_cet_check cet_check
+#include <sysdeps/x86/dl-cet.c>
+#undef _dl_cet_check
+
+#ifdef SHARED
+void
+_dl_cet_check (struct link_map *main_map, const char *program)
+{
+ cet_check (main_map, program);
+
+ if ((GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_SHSTK))
+ {
+ /* Replace _dl_runtime_resolve and _dl_runtime_profile with
+ _dl_runtime_resolve_shstk and _dl_runtime_profile_shstk,
+ respectively if SHSTK is enabled. */
+ extern void _dl_runtime_resolve (Elf32_Word) attribute_hidden;
+ extern void _dl_runtime_resolve_shstk (Elf32_Word) attribute_hidden;
+ extern void _dl_runtime_profile (Elf32_Word) attribute_hidden;
+ extern void _dl_runtime_profile_shstk (Elf32_Word) attribute_hidden;
+ unsigned int i;
+ struct link_map *l;
+ Elf32_Addr *got;
+
+ if (main_map->l_info[DT_JMPREL])
+ {
+ got = (Elf32_Addr *) D_PTR (main_map, l_info[DT_PLTGOT]);
+ if (got[2] == (Elf32_Addr) &_dl_runtime_resolve)
+ got[2] = (Elf32_Addr) &_dl_runtime_resolve_shstk;
+ else if (got[2] == (Elf32_Addr) &_dl_runtime_profile)
+ got[2] = (Elf32_Addr) &_dl_runtime_profile_shstk;
+ }
+
+ i = main_map->l_searchlist.r_nlist;
+ while (i-- > 0)
+ {
+ l = main_map->l_initfini[i];
+ if (l->l_info[DT_JMPREL])
+ {
+ got = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
+ if (got[2] == (Elf32_Addr) &_dl_runtime_resolve)
+ got[2] = (Elf32_Addr) &_dl_runtime_resolve_shstk;
+ else if (got[2] == (Elf32_Addr) &_dl_runtime_profile)
+ got[2] = (Elf32_Addr) &_dl_runtime_profile_shstk;
+ }
+ }
+ }
+}
+#endif
diff --git a/sysdeps/i386/dl-trampoline.S b/sysdeps/i386/dl-trampoline.S
index 8bf86f8fd9..6dc0319216 100644
--- a/sysdeps/i386/dl-trampoline.S
+++ b/sysdeps/i386/dl-trampoline.S
@@ -32,6 +32,7 @@
.align 16
_dl_runtime_resolve:
cfi_adjust_cfa_offset (8)
+ _CET_ENDBR
pushl %eax # Preserve registers otherwise clobbered.
cfi_adjust_cfa_offset (4)
pushl %ecx
@@ -50,14 +51,85 @@ _dl_runtime_resolve:
cfi_endproc
.size _dl_runtime_resolve, .-_dl_runtime_resolve
+# The SHSTK compatible version.
+ .text
+ .globl _dl_runtime_resolve_shstk
+ .type _dl_runtime_resolve_shstk, @function
+ cfi_startproc
+ .align 16
+_dl_runtime_resolve_shstk:
+ cfi_adjust_cfa_offset (8)
+ _CET_ENDBR
+ pushl %eax # Preserve registers otherwise clobbered.
+ cfi_adjust_cfa_offset (4)
+ pushl %edx
+ cfi_adjust_cfa_offset (4)
+ movl 12(%esp), %edx # Copy args pushed by PLT in register. Note
+ movl 8(%esp), %eax # that `fixup' takes its parameters in regs.
+ call _dl_fixup # Call resolver.
+ movl (%esp), %edx # Get register content back.
+ movl %eax, %ecx # Store the function address.
+ movl 4(%esp), %eax # Get register content back.
+ addl $16, %esp # Adjust stack: PLT1 + PLT2 + %eax + %edx
+ cfi_adjust_cfa_offset (-16)
+ jmp *%ecx # Jump to function address.
+ cfi_endproc
+ .size _dl_runtime_resolve_shstk, .-_dl_runtime_resolve_shstk
#ifndef PROF
+# The SHSTK compatible version.
+ .globl _dl_runtime_profile_shstk
+ .type _dl_runtime_profile_shstk, @function
+ cfi_startproc
+ .align 16
+_dl_runtime_profile_shstk:
+ cfi_adjust_cfa_offset (8)
+ _CET_ENDBR
+ pushl %esp
+ cfi_adjust_cfa_offset (4)
+ addl $8, (%esp) # Account for the pushed PLT data
+ pushl %ebp
+ cfi_adjust_cfa_offset (4)
+ pushl %eax # Preserve registers otherwise clobbered.
+ cfi_adjust_cfa_offset (4)
+ pushl %ecx
+ cfi_adjust_cfa_offset (4)
+ pushl %edx
+ cfi_adjust_cfa_offset (4)
+ movl %esp, %ecx
+ subl $8, %esp
+ cfi_adjust_cfa_offset (8)
+ movl $-1, 4(%esp)
+ leal 4(%esp), %edx
+ movl %edx, (%esp)
+ pushl %ecx # Address of the register structure
+ cfi_adjust_cfa_offset (4)
+ movl 40(%esp), %ecx # Load return address
+ movl 36(%esp), %edx # Copy args pushed by PLT in register. Note
+ movl 32(%esp), %eax # that `fixup' takes its parameters in regs.
+ call _dl_profile_fixup # Call resolver.
+ cfi_adjust_cfa_offset (-8)
+ movl (%esp), %edx
+ testl %edx, %edx
+ jns 1f
+ movl 4(%esp), %edx # Get register content back.
+ movl %eax, %ecx # Store the function address.
+ movl 12(%esp), %eax # Get register content back.
+ # Adjust stack: PLT1 + PLT2 + %esp + %ebp + %eax + %ecx + %edx
+ # + free.
+ addl $32, %esp
+ cfi_adjust_cfa_offset (-32)
+ jmp *%ecx # Jump to function address.
+ cfi_endproc
+ .size _dl_runtime_profile_shstk, .-_dl_runtime_profile_shstk
+
.globl _dl_runtime_profile
.type _dl_runtime_profile, @function
cfi_startproc
.align 16
_dl_runtime_profile:
cfi_adjust_cfa_offset (8)
+ _CET_ENDBR
pushl %esp
cfi_adjust_cfa_offset (4)
addl $8, (%esp) # Account for the pushed PLT data
diff --git a/sysdeps/unix/sysv/linux/x86/cpu-features.c b/sysdeps/unix/sysv/linux/x86/cpu-features.c
new file mode 100644
index 0000000000..0fa7901245
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/cpu-features.c
@@ -0,0 +1,38 @@
+/* Initialize CPU feature data for Linux/x86.
+ This file is part of the GNU C Library.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifdef __CET__
+static inline int __attribute__ ((always_inline))
+get_cet_status (unsigned long *cet_status)
+{
+ return -1;
+}
+
+# ifndef SHARED
+static inline void
+x86_setup_tls (void)
+{
+ __libc_setup_tls ();
+ THREAD_SETMEM (THREAD_SELF, header.feature_1, GL(dl_x86_feature_1)[0]);
+}
+
+# define ARCH_SETUP_TLS() x86_setup_tls ()
+# endif
+#endif
+
+#include <sysdeps/x86/cpu-features.c>
diff --git a/sysdeps/unix/sysv/linux/x86/dl-cet.h b/sysdeps/unix/sysv/linux/x86/dl-cet.h
new file mode 100644
index 0000000000..9903bbe41f
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/dl-cet.h
@@ -0,0 +1,34 @@
+/* Linux/x86 CET initializers function.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+static inline int __attribute__ ((always_inline))
+dl_cet_allocate_legacy_bitmap (unsigned long *legacy_bitmap)
+{
+ return -1;
+}
+
+static inline int __attribute__ ((always_inline))
+dl_cet_disable_cet (unsigned int cet_feature)
+{
+ return -1;
+}
+
+static inline int __attribute__ ((always_inline))
+dl_cet_lock_cet (void)
+{
+ return -1;
+}
diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
index 65292f4032..e9b2d0b35d 100644
--- a/sysdeps/x86/Makefile
+++ b/sysdeps/x86/Makefile
@@ -13,3 +13,45 @@ ifeq ($(subdir),setjmp)
gen-as-const-headers += jmp_buf-ssp.sym
sysdep_routines += __longjmp_cancel
endif
+
+ifeq ($(enable-cet),yes)
+ifeq ($(subdir),elf)
+sysdep-dl-routines += dl-cet
+endif
+
+# Add -fcf-protection to CFLAGS when CET is enabled.
+CFLAGS-.o += -fcf-protection
+CFLAGS-.os += -fcf-protection
+CFLAGS-.op += -fcf-protection
+CFLAGS-.oS += -fcf-protection
+
+# Compile assembly codes with <cet.h> when CET is enabled.
+asm-CPPFLAGS += -fcf-protection -include cet.h
+
+ifeq ($(subdir),elf)
+ifeq (yes,$(build-shared))
+tests-special += $(objpfx)check-cet.out
+endif
+
+# FIXME: Can't use all-built-dso in elf/Makefile since this file is
+# processed before elf/Makefile. Duplicate it here.
+cet-built-dso := $(common-objpfx)elf/ld.so $(common-objpfx)libc.so \
+ $(filter-out $(common-objpfx)linkobj/libc.so, \
+ $(sort $(wildcard $(addprefix $(common-objpfx), \
+ */lib*.so \
+ iconvdata/*.so))))
+
+$(cet-built-dso:=.note): %.note: %
+ @rm -f $@T
+ LC_ALL=C $(READELF) -n $< > $@T
+ test -s $@T
+ mv -f $@T $@
+common-generated += $(cet-built-dso:$(common-objpfx)%=%.note)
+
+$(objpfx)check-cet.out: $(..)sysdeps/x86/check-cet.awk \
+ $(cet-built-dso:=.note)
+ LC_ALL=C $(AWK) -f $^ > $@; \
+ $(evaluate-test)
+generated += check-cet.out
+endif
+endif
diff --git a/sysdeps/x86/cet-tunables.h b/sysdeps/x86/cet-tunables.h
new file mode 100644
index 0000000000..ca023053ee
--- /dev/null
+++ b/sysdeps/x86/cet-tunables.h
@@ -0,0 +1,29 @@
+/* x86 CET tuning.
+ This file is part of the GNU C Library.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+/* Valid control values:
+ 0: Enable CET features based on ELF property note.
+ 1: Always disable CET features.
+ 2: Always enable CET features.
+ 3: Enable CET features permissively.
+ */
+#define CET_ELF_PROPERTY 0
+#define CET_ALWAYS_OFF 1
+#define CET_ALWAYS_ON 2
+#define CET_PERMISSIVE 3
+#define CET_MAX CET_PERMISSIVE
diff --git a/sysdeps/x86/check-cet.awk b/sysdeps/x86/check-cet.awk
new file mode 100644
index 0000000000..380d998caf
--- /dev/null
+++ b/sysdeps/x86/check-cet.awk
@@ -0,0 +1,53 @@
+# Verify that all shared objects contain the CET property.
+# Copyright (C) 2018 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+# This awk script expects to get command-line files that are each
+# the output of 'readelf -n' on a single shared object.
+# It exits successfully (0) if all of them contained the CET property.
+# It fails (1) if any didn't contain the CET property
+# It fails (2) if the input did not take the expected form.
+
+BEGIN { result = cet = sanity = 0 }
+
+function check_one(name) {
+ if (!sanity) {
+ print name ": *** input did not look like readelf -n output";
+ result = 2;
+ } else if (cet) {
+ print name ": OK";
+ } else {
+ print name ": *** no CET property found";
+ result = result ? result : 1;
+ }
+
+ cet = sanity = 0;
+}
+
+FILENAME != lastfile {
+ if (lastfile)
+ check_one(lastfile);
+ lastfile = FILENAME;
+}
+
+index ($0, "Displaying notes") != 0 { sanity = 1 }
+index ($0, "IBT") != 0 && index ($0, "SHSTK") != 0 { cet = 1 }
+
+END {
+ check_one(lastfile);
+ exit(result);
+}
diff --git a/sysdeps/x86/configure b/sysdeps/x86/configure
new file mode 100644
index 0000000000..b1ff281249
--- /dev/null
+++ b/sysdeps/x86/configure
@@ -0,0 +1,69 @@
+# This file is generated from configure.ac by Autoconf. DO NOT EDIT!
+ # Local configure fragment for sysdeps/x86.
+
+if test x"$enable_cet" = xyes; then
+ # Check if CET can be enabled.
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether CET can be enabled" >&5
+$as_echo_n "checking whether CET can be enabled... " >&6; }
+if ${libc_cv_x86_cet_available+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ cat > conftest.c <<EOF
+#if !defined __CET__ || __CET__ != 3
+# error CET isn't available.
+#endif
+EOF
+ if { ac_try='${CC-cc} -c $CFLAGS -fcf-protection -include cet.h conftest.c 1>&5'
+ { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+ test $ac_status = 0; }; }; then
+ libc_cv_x86_cet_available=yes
+ else
+ libc_cv_x86_cet_available=no
+ fi
+ rm -rf conftest*
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_x86_cet_available" >&5
+$as_echo "$libc_cv_x86_cet_available" >&6; }
+ if test $libc_cv_x86_cet_available = yes; then
+ enable_cet=yes
+ else
+ if test x"$enable_cet" = xdefault; then
+ enable_cet=no
+ else
+ as_fn_error $? "$CC doesn't support CET" "$LINENO" 5
+ fi
+ fi
+fi
+if test $enable_cet = yes; then
+ # Check if assembler supports CET.
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $AS supports CET" >&5
+$as_echo_n "checking whether $AS supports CET... " >&6; }
+if ${libc_cv_x86_cet_as+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ cat > conftest.s <<EOF
+ incsspd %ecx
+EOF
+ if { ac_try='${CC-cc} -c $CFLAGS conftest.s -o conftest.o 1>&5'
+ { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+ test $ac_status = 0; }; }; then
+ libc_cv_x86_cet_as=yes
+ else
+ libc_cv_x86_cet_as=no
+ fi
+ rm -rf conftest*
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_x86_cet_as" >&5
+$as_echo "$libc_cv_x86_cet_as" >&6; }
+ if test $libc_cv_x86_cet_as = no; then
+ as_fn_error $? "$AS doesn't support CET" "$LINENO" 5
+ fi
+fi
+config_vars="$config_vars
+enable-cet = $enable_cet"
diff --git a/sysdeps/x86/configure.ac b/sysdeps/x86/configure.ac
new file mode 100644
index 0000000000..a909b073af
--- /dev/null
+++ b/sysdeps/x86/configure.ac
@@ -0,0 +1,46 @@
+GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.
+# Local configure fragment for sysdeps/x86.
+
+if test x"$enable_cet" = xyes; then
+ # Check if CET can be enabled.
+ AC_CACHE_CHECK(whether CET can be enabled,
+ libc_cv_x86_cet_available, [dnl
+cat > conftest.c <<EOF
+#if !defined __CET__ || __CET__ != 3
+# error CET isn't available.
+#endif
+EOF
+ if AC_TRY_COMMAND(${CC-cc} -c $CFLAGS -fcf-protection -include cet.h conftest.c 1>&AS_MESSAGE_LOG_FD); then
+ libc_cv_x86_cet_available=yes
+ else
+ libc_cv_x86_cet_available=no
+ fi
+ rm -rf conftest*])
+ if test $libc_cv_x86_cet_available = yes; then
+ enable_cet=yes
+ else
+ if test x"$enable_cet" = xdefault; then
+ enable_cet=no
+ else
+ AC_MSG_ERROR([$CC doesn't support CET])
+ fi
+ fi
+fi
+if test $enable_cet = yes; then
+ # Check if assembler supports CET.
+ AC_CACHE_CHECK(whether $AS supports CET,
+ libc_cv_x86_cet_as, [dnl
+cat > conftest.s <<EOF
+ incsspd %ecx
+EOF
+ if AC_TRY_COMMAND(${CC-cc} -c $CFLAGS conftest.s -o conftest.o 1>&AS_MESSAGE_LOG_FD); then
+ libc_cv_x86_cet_as=yes
+ else
+ libc_cv_x86_cet_as=no
+ fi
+ rm -rf conftest*])
+ if test $libc_cv_x86_cet_as = no; then
+ AC_MSG_ERROR([$AS doesn't support CET])
+ fi
+fi
+LIBC_CONFIG_VAR([enable-cet], [$enable_cet])
diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index d41ebde823..32edbe6af0 100644
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -28,6 +28,15 @@
extern void TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *)
attribute_hidden;
+
+# ifdef __CET__
+# include <dl-cet.h>
+# include <cet-tunables.h>
+extern void TUNABLE_CALLBACK (set_x86_ibt) (tunable_val_t *)
+ attribute_hidden;
+extern void TUNABLE_CALLBACK (set_x86_shstk) (tunable_val_t *)
+ attribute_hidden;
+# endif
#endif
static void
@@ -200,6 +209,17 @@ init_cpu_features (struct cpu_features *cpu_features)
}
#endif
+#ifdef __CET__
+ /* Check CET status. */
+ unsigned long cet_status[3];
+ int res = get_cet_status (cet_status);
+ if (res == 0)
+ {
+ /* Update dl_x86_feature_1. */
+ GL(dl_x86_feature_1)[0] = cet_status[0];
+ }
+#endif
+
__cpuid (0, cpu_features->max_cpuid, ebx, ecx, edx);
/* This spells out "GenuineIntel". */
@@ -449,4 +469,49 @@ no_cpuid:
else if (CPU_FEATURES_ARCH_P (cpu_features, I586))
GLRO(dl_platform) = "i586";
#endif
+
+#ifdef __CET__
+# if HAVE_TUNABLES
+ TUNABLE_GET (x86_ibt, tunable_val_t *,
+ TUNABLE_CALLBACK (set_x86_ibt));
+ TUNABLE_GET (x86_shstk, tunable_val_t *,
+ TUNABLE_CALLBACK (set_x86_shstk));
+# endif
+
+ if (res == 0)
+ {
+# ifndef SHARED
+ /* Check if IBT and SHSTK are enabled by kernel. */
+ if ((GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_IBT)
+ || (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_SHSTK))
+ {
+ /* Disable IBT and/or SHSTK if they are enabled by kernel, but
+ disabled by environment variable:
+
+ GLIBC_TUNABLES=glibc.tune.hwcaps=-IBT,-SHSTK
+ */
+ unsigned int cet_feature = 0;
+ if (!HAS_CPU_FEATURE (IBT))
+ cet_feature |= GNU_PROPERTY_X86_FEATURE_1_IBT;
+ if (!HAS_CPU_FEATURE (SHSTK))
+ cet_feature |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
+
+ if (cet_feature)
+ {
+ int res = dl_cet_disable_cet (cet_feature);
+
+ /* Clear the disabled bits in dl_x86_feature_1. */
+ if (res == 0)
+ GL(dl_x86_feature_1)[0] &= ~cet_feature;
+ }
+
+ /* Lock CET if IBT or SHSTK is enabled in executable. Don't
+ lock CET if SHSTK is enabled permissively. */
+ if (((cet_status[1] >> CET_MAX) & ((1 << CET_MAX) - 1))
+ != CET_PERMISSIVE)
+ dl_cet_lock_cet ();
+ }
+# endif
+ }
+#endif
}
diff --git a/sysdeps/x86/cpu-tunables.c b/sysdeps/x86/cpu-tunables.c
index af761dcbbc..a5c0153348 100644
--- a/sysdeps/x86/cpu-tunables.c
+++ b/sysdeps/x86/cpu-tunables.c
@@ -334,4 +334,52 @@ TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp)
}
while (*p != '\0');
}
+
+# ifdef __CET__
+# include <cet-tunables.h>
+
+attribute_hidden
+void
+TUNABLE_CALLBACK (set_x86_ibt) (tunable_val_t *valp)
+{
+ if (DEFAULT_MEMCMP (valp->strval, "on", sizeof ("on")) == 0)
+ {
+ GL(dl_x86_feature_1)[1] &= ~((1 << CET_MAX) - 1);
+ GL(dl_x86_feature_1)[1] |= CET_ALWAYS_ON;
+ }
+ else if (DEFAULT_MEMCMP (valp->strval, "off", sizeof ("off")) == 0)
+ {
+ GL(dl_x86_feature_1)[1] &= ~((1 << CET_MAX) - 1);
+ GL(dl_x86_feature_1)[1] |= CET_ALWAYS_OFF;
+ }
+ else if (DEFAULT_MEMCMP (valp->strval, "permissive",
+ sizeof ("permissive")) == 0)
+ {
+ GL(dl_x86_feature_1)[1] &= ~((1 << CET_MAX) - 1);
+ GL(dl_x86_feature_1)[1] |= CET_PERMISSIVE;
+ }
+}
+
+attribute_hidden
+void
+TUNABLE_CALLBACK (set_x86_shstk) (tunable_val_t *valp)
+{
+ if (DEFAULT_MEMCMP (valp->strval, "on", sizeof ("on")) == 0)
+ {
+ GL(dl_x86_feature_1)[1] &= ~(((1 << CET_MAX) - 1) << CET_MAX);
+ GL(dl_x86_feature_1)[1] |= (CET_ALWAYS_ON << CET_MAX);
+ }
+ else if (DEFAULT_MEMCMP (valp->strval, "off", sizeof ("off")) == 0)
+ {
+ GL(dl_x86_feature_1)[1] &= ~(((1 << CET_MAX) - 1) << CET_MAX);
+ GL(dl_x86_feature_1)[1] |= (CET_ALWAYS_OFF << CET_MAX);
+ }
+ else if (DEFAULT_MEMCMP (valp->strval, "permissive",
+ sizeof ("permissive")) == 0)
+ {
+ GL(dl_x86_feature_1)[1] &= ~(((1 << CET_MAX) - 1) << CET_MAX);
+ GL(dl_x86_feature_1)[1] |= (CET_PERMISSIVE << CET_MAX);
+ }
+}
+# endif
#endif
diff --git a/sysdeps/x86/dl-cet.c b/sysdeps/x86/dl-cet.c
new file mode 100644
index 0000000000..5018e4560d
--- /dev/null
+++ b/sysdeps/x86/dl-cet.c
@@ -0,0 +1,335 @@
+/* x86 CET initializers function.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <unistd.h>
+#include <errno.h>
+#include <libintl.h>
+#include <ldsodefs.h>
+#include <dl-cet.h>
+#include <cet-tunables.h>
+
+static int
+dl_cet_mark_legacy_region (struct link_map *l)
+{
+ /* Mark PT_LOAD segments with PF_X in legacy code page bitmap. */
+ size_t i, phnum = l->l_phnum;
+ const ElfW(Phdr) *phdr = l->l_phdr;
+#ifdef __x86_64__
+ typedef unsigned long long word_t;
+#else
+ typedef unsigned long word_t;
+#endif
+ unsigned int bits_to_set;
+ word_t mask_to_set;
+#define BITS_PER_WORD (sizeof (word_t) * 8)
+#define BITMAP_FIRST_WORD_MASK(start) \
+ (~((word_t) 0) << ((start) & (BITS_PER_WORD - 1)))
+#define BITMAP_LAST_WORD_MASK(nbits) \
+ (~((word_t) 0) >> (-(nbits) & (BITS_PER_WORD - 1)))
+
+ word_t *bitmap = (word_t *) GL(dl_x86_legacy_bitmap)[0];
+ word_t bitmap_size = GL(dl_x86_legacy_bitmap)[1];
+ word_t *p;
+ size_t page_size = GLRO(dl_pagesize);
+
+ for (i = 0; i < phnum; i++)
+ if (phdr[i].p_type == PT_LOAD && (phdr[i].p_flags & PF_X))
+ {
+ /* One bit in legacy bitmap represents a page. */
+ ElfW(Addr) start = (phdr[i].p_vaddr + l->l_addr) / page_size;
+ ElfW(Addr) len = (phdr[i].p_memsz + page_size - 1) / page_size;
+ ElfW(Addr) end = start + len;
+
+ if ((end / 8) > bitmap_size)
+ return -EFAULT;
+
+ p = bitmap + (start / BITS_PER_WORD);
+ bits_to_set = BITS_PER_WORD - (start % BITS_PER_WORD);
+ mask_to_set = BITMAP_FIRST_WORD_MASK (start);
+
+ while (len >= bits_to_set)
+ {
+ *p |= mask_to_set;
+ len -= bits_to_set;
+ bits_to_set = BITS_PER_WORD;
+ mask_to_set = ~((word_t) 0);
+ p++;
+ }
+ if (len)
+ {
+ mask_to_set &= BITMAP_LAST_WORD_MASK (end);
+ *p |= mask_to_set;
+ }
+ }
+
+ return 0;
+}
+
+/* Check if object M is compatible with CET. */
+
+static void
+dl_cet_check (struct link_map *m, const char *program)
+{
+ /* Check how IBT should be enabled. */
+ unsigned int enable_ibt_type
+ = GL(dl_x86_feature_1)[1] & ((1 << CET_MAX) - 1);
+ /* Check how SHSTK should be enabled. */
+ unsigned int enable_shstk_type
+ = ((GL(dl_x86_feature_1)[1] >> CET_MAX) & ((1 << CET_MAX) - 1));
+
+ /* No legacy object check if both IBT and SHSTK are always on. */
+ if (enable_ibt_type == CET_ALWAYS_ON
+ && enable_shstk_type == CET_ALWAYS_ON)
+ return;
+
+ /* Check if IBT is enabled by kernel. */
+ bool ibt_enabled
+ = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0;
+ /* Check if SHSTK is enabled by kernel. */
+ bool shstk_enabled
+ = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0;
+
+ if (ibt_enabled || shstk_enabled)
+ {
+ struct link_map *l = NULL;
+
+ /* Check if IBT and SHSTK are enabled in object. */
+ bool enable_ibt = (ibt_enabled
+ && enable_ibt_type != CET_ALWAYS_OFF);
+ bool enable_shstk = (shstk_enabled
+ && enable_shstk_type != CET_ALWAYS_OFF);
+ if (program)
+ {
+ /* Enable IBT and SHSTK only if they are enabled in executable.
+ NB: IBT and SHSTK may be disabled by environment variable:
+
+ GLIBC_TUNABLES=glibc.tune.hwcaps=-IBT,-SHSTK
+ */
+ enable_ibt &= (HAS_CPU_FEATURE (IBT)
+ && (enable_ibt_type == CET_ALWAYS_ON
+ || (m->l_cet & lc_ibt) != 0));
+ enable_shstk &= (HAS_CPU_FEATURE (SHSTK)
+ && (enable_shstk_type == CET_ALWAYS_ON
+ || (m->l_cet & lc_shstk) != 0));
+ }
+
+ /* ld.so is CET-enabled by kernel. But shared objects may not
+ support IBT nor SHSTK. */
+ if (enable_ibt || enable_shstk)
+ {
+ int res;
+ unsigned int i;
+ unsigned int first_legacy, last_legacy;
+ bool need_legacy_bitmap = false;
+
+ i = m->l_searchlist.r_nlist;
+ while (i-- > 0)
+ {
+ /* Check each shared object to see if IBT and SHSTK are
+ enabled. */
+ l = m->l_initfini[i];
+
+ if (l->l_init_called)
+ continue;
+
+#ifdef SHARED
+ /* Skip CET check for ld.so since ld.so is CET-enabled.
+ CET will be disabled later if CET isn't enabled in
+ executable. */
+ if (l == &GL(dl_rtld_map)
+ || l->l_real == &GL(dl_rtld_map)
+ || (program && l == m))
+ continue;
+#endif
+
+ if (enable_ibt
+ && enable_ibt_type != CET_ALWAYS_ON
+ && !(l->l_cet & lc_ibt))
+ {
+ /* Remember the first and last legacy objects. */
+ if (!need_legacy_bitmap)
+ last_legacy = i;
+ first_legacy = i;
+ need_legacy_bitmap = true;
+ }
+
+ /* SHSTK is enabled only if it is enabled in executable as
+ well as all shared objects. */
+ enable_shstk &= (enable_shstk_type == CET_ALWAYS_ON
+ || (l->l_cet & lc_shstk) != 0);
+ }
+
+ if (need_legacy_bitmap)
+ {
+ if (GL(dl_x86_legacy_bitmap)[0])
+ {
+ /* Change legacy bitmap to writable. */
+ if (__mprotect ((void *) GL(dl_x86_legacy_bitmap)[0],
+ GL(dl_x86_legacy_bitmap)[1],
+ PROT_READ | PROT_WRITE) < 0)
+ {
+mprotect_failure:
+ if (program)
+ _dl_fatal_printf ("%s: mprotect legacy bitmap failed\n",
+ l->l_name);
+ else
+ _dl_signal_error (EINVAL, l->l_name, "dlopen",
+ N_("mprotect legacy bitmap failed"));
+ }
+ }
+ else
+ {
+ /* Allocate legacy bitmap. */
+ int res = dl_cet_allocate_legacy_bitmap
+ (GL(dl_x86_legacy_bitmap));
+ if (res != 0)
+ {
+ if (program)
+ _dl_fatal_printf ("%s: legacy bitmap isn't available\n",
+ l->l_name);
+ else
+ _dl_signal_error (EINVAL, l->l_name, "dlopen",
+ N_("legacy bitmap isn't available"));
+ }
+ }
+
+ /* Put legacy shared objects in legacy bitmap. */
+ for (i = first_legacy; i <= last_legacy; i++)
+ {
+ l = m->l_initfini[i];
+
+ if (l->l_init_called || (l->l_cet & lc_ibt))
+ continue;
+
+#ifdef SHARED
+ if (l == &GL(dl_rtld_map)
+ || l->l_real == &GL(dl_rtld_map)
+ || (program && l == m))
+ continue;
+#endif
+
+ /* If IBT is enabled in executable and IBT isn't enabled
+ in this shard object, mark PT_LOAD segments with PF_X
+ in legacy code page bitmap. */
+ res = dl_cet_mark_legacy_region (l);
+ if (res != 0)
+ {
+ if (program)
+ _dl_fatal_printf ("%s: fail to mark legacy code region\n",
+ l->l_name);
+ else
+ _dl_signal_error (-res, l->l_name, "dlopen",
+ N_("fail to mark legacy code region"));
+ }
+ }
+
+ /* Change legacy bitmap to read-only. */
+ if (__mprotect ((void *) GL(dl_x86_legacy_bitmap)[0],
+ GL(dl_x86_legacy_bitmap)[1], PROT_READ) < 0)
+ goto mprotect_failure;
+ }
+ }
+
+ bool cet_feature_changed = false;
+
+ if (enable_ibt != ibt_enabled || enable_shstk != shstk_enabled)
+ {
+ if (!program
+ && enable_shstk_type != CET_PERMISSIVE)
+ {
+ /* When SHSTK is enabled, we can't dlopening a shared
+ object without SHSTK. */
+ if (enable_shstk != shstk_enabled)
+ _dl_signal_error (EINVAL, l->l_name, "dlopen",
+ N_("shadow stack isn't enabled"));
+ return;
+ }
+
+ /* Disable IBT and/or SHSTK if they are enabled by kernel, but
+ disabled in executable or shared objects. */
+ unsigned int cet_feature = 0;
+
+ /* Disable IBT only during program startup. */
+ if (program && !enable_ibt)
+ cet_feature |= GNU_PROPERTY_X86_FEATURE_1_IBT;
+ if (!enable_shstk)
+ cet_feature |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
+
+ int res = dl_cet_disable_cet (cet_feature);
+ if (res != 0)
+ {
+ if (program)
+ _dl_fatal_printf ("%s: can't disable CET\n", program);
+ else
+ _dl_signal_error (-res, l->l_name, "dlopen",
+ N_("can't disable CET"));
+ }
+
+ /* Clear the disabled bits in dl_x86_feature_1. */
+ GL(dl_x86_feature_1)[0] &= ~cet_feature;
+
+ cet_feature_changed = true;
+ }
+
+#ifdef SHARED
+ if (program
+ && (!shstk_enabled
+ || enable_shstk_type != CET_PERMISSIVE)
+ && (ibt_enabled || shstk_enabled))
+ {
+ /* Lock CET if IBT or SHSTK is enabled in executable. Don't
+ lock CET if SHSTK is enabled permissively. */
+ int res = dl_cet_lock_cet ();
+ if (res != 0)
+ _dl_fatal_printf ("%s: can't lock CET\n", program);
+
+ cet_feature_changed = true;
+ }
+#endif
+
+ if (cet_feature_changed)
+ {
+ unsigned int feature_1 = 0;
+ if (enable_ibt)
+ feature_1 |= GNU_PROPERTY_X86_FEATURE_1_IBT;
+ if (enable_shstk)
+ feature_1 |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
+ struct pthread *self = THREAD_SELF;
+ THREAD_SETMEM (self, header.feature_1, feature_1);
+ }
+ }
+}
+
+void
+_dl_cet_open_check (struct link_map *l)
+{
+ dl_cet_check (l, NULL);
+}
+
+#ifdef SHARED
+
+# ifndef LINKAGE
+# define LINKAGE
+# endif
+
+LINKAGE
+void
+_dl_cet_check (struct link_map *main_map, const char *program)
+{
+ dl_cet_check (main_map, program);
+}
+#endif /* SHARED */
diff --git a/sysdeps/x86/dl-procruntime.c b/sysdeps/x86/dl-procruntime.c
new file mode 100644
index 0000000000..eddbde6a31
--- /dev/null
+++ b/sysdeps/x86/dl-procruntime.c
@@ -0,0 +1,68 @@
+/* Data for processor runtime information. x86 version.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+/* This information must be kept in sync with the _DL_HWCAP_COUNT,
+ HWCAP_PLATFORMS_START and HWCAP_PLATFORMS_COUNT definitions in
+ dl-hwcap.h.
+
+ If anything should be added here check whether the size of each string
+ is still ok with the given array size.
+
+ All the #ifdefs in the definitions are quite irritating but
+ necessary if we want to avoid duplicating the information. There
+ are three different modes:
+
+ - PROCINFO_DECL is defined. This means we are only interested in
+ declarations.
+
+ - PROCINFO_DECL is not defined:
+
+ + if SHARED is defined the file is included in an array
+ initializer. The .element = { ... } syntax is needed.
+
+ + if SHARED is not defined a normal array initialization is
+ needed.
+ */
+
+#ifndef PROCINFO_CLASS
+# define PROCINFO_CLASS
+#endif
+
+#if !IS_IN (ldconfig)
+# if !defined PROCINFO_DECL && defined SHARED
+ ._dl_x86_feature_1
+# else
+PROCINFO_CLASS unsigned int _dl_x86_feature_1[2]
+# endif
+# if !defined SHARED || defined PROCINFO_DECL
+;
+# else
+,
+# endif
+
+# if !defined PROCINFO_DECL && defined SHARED
+ ._dl_x86_legacy_bitmap
+# else
+PROCINFO_CLASS unsigned long _dl_x86_legacy_bitmap[2]
+# endif
+# if !defined SHARED || defined PROCINFO_DECL
+;
+# else
+,
+# endif
+#endif
diff --git a/sysdeps/x86/dl-prop.h b/sysdeps/x86/dl-prop.h
new file mode 100644
index 0000000000..2709fe852d
--- /dev/null
+++ b/sysdeps/x86/dl-prop.h
@@ -0,0 +1,153 @@
+/* Support for GNU properties. x86 version.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef _DL_PROP_H
+#define _DL_PROP_H
+
+#include <not-cancel.h>
+
+extern void _dl_cet_check (struct link_map *, const char *)
+ attribute_hidden;
+extern void _dl_cet_open_check (struct link_map *)
+ attribute_hidden;
+
+static inline void __attribute__ ((always_inline))
+_rtld_main_check (struct link_map *m, const char *program)
+{
+#ifdef __CET__
+ _dl_cet_check (m, program);
+#endif
+}
+
+static inline void __attribute__ ((always_inline))
+_dl_open_check (struct link_map *m)
+{
+#ifdef __CET__
+ _dl_cet_open_check (m);
+#endif
+}
+
+static inline void __attribute__ ((unused))
+_dl_process_cet_property_note (struct link_map *l,
+ const ElfW(Nhdr) *note,
+ const ElfW(Addr) size,
+ const ElfW(Addr) align)
+{
+#ifdef __CET__
+ /* The NT_GNU_PROPERTY_TYPE_0 note must be aliged to 4 bytes in
+ 32-bit objects and to 8 bytes in 64-bit objects. Skip notes
+ with incorrect alignment. */
+ if (align != (__ELF_NATIVE_CLASS / 8))
+ return;
+
+ const ElfW(Addr) start = (ElfW(Addr)) note;
+
+ while ((ElfW(Addr)) (note + 1) - start < size)
+ {
+ /* Find the NT_GNU_PROPERTY_TYPE_0 note. */
+ if (note->n_namesz == 4
+ && note->n_type == NT_GNU_PROPERTY_TYPE_0
+ && memcmp (note + 1, "GNU", 4) == 0)
+ {
+ /* Check for invalid property. */
+ if (note->n_descsz < 8
+ || (note->n_descsz % sizeof (ElfW(Addr))) != 0)
+ break;
+
+ /* Start and end of property array. */
+ unsigned char *ptr = (unsigned char *) (note + 1) + 4;
+ unsigned char *ptr_end = ptr + note->n_descsz;
+
+ while (1)
+ {
+ unsigned int type = *(unsigned int *) ptr;
+ unsigned int datasz = *(unsigned int *) (ptr + 4);
+
+ ptr += 8;
+ if ((ptr + datasz) > ptr_end)
+ break;
+
+ if (type == GNU_PROPERTY_X86_FEATURE_1_AND
+ && datasz == 4)
+ {
+ unsigned int feature_1 = *(unsigned int *) ptr;
+ if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_IBT))
+ l->l_cet |= lc_ibt;
+ if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_SHSTK))
+ l->l_cet |= lc_shstk;
+ break;
+ }
+ }
+ }
+
+ /* NB: Note sections like .note.ABI-tag and .note.gnu.build-id are
+ aligned to 4 bytes in 64-bit ELF objects. */
+ note = ((const void *) note
+ + ELF_NOTE_NEXT_OFFSET (note->n_namesz, note->n_descsz,
+ align));
+ }
+#endif
+}
+
+#ifdef FILEBUF_SIZE
+static inline int __attribute__ ((unused))
+_dl_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph,
+ int fd, struct filebuf *fbp)
+{
+# ifdef __CET__
+ const ElfW(Nhdr) *note;
+ ElfW(Nhdr) *note_malloced = NULL;
+ ElfW(Addr) size = ph->p_filesz;
+
+ if (ph->p_offset + size <= (size_t) fbp->len)
+ note = (const void *) (fbp->buf + ph->p_offset);
+ else
+ {
+ if (size < __MAX_ALLOCA_CUTOFF)
+ note = alloca (size);
+ else
+ {
+ note_malloced = malloc (size);
+ note = note_malloced;
+ }
+ __lseek (fd, ph->p_offset, SEEK_SET);
+ if (__read_nocancel (fd, (void *) note, size) != size)
+ {
+ if (note_malloced)
+ free (note_malloced);
+ return -1;
+ }
+ }
+
+ _dl_process_cet_property_note (l, note, size, ph->p_align);
+ if (note_malloced)
+ free (note_malloced);
+# endif
+ return 0;
+}
+#endif
+
+static inline int __attribute__ ((unused))
+_rtld_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph)
+{
+ const ElfW(Nhdr) *note = (const void *) (ph->p_vaddr + l->l_addr);
+ _dl_process_cet_property_note (l, note, ph->p_memsz, ph->p_align);
+ return 0;
+}
+
+#endif /* _DL_PROP_H */
diff --git a/sysdeps/x86/dl-tunables.list b/sysdeps/x86/dl-tunables.list
index 7c3236a68f..73886b1352 100644
--- a/sysdeps/x86/dl-tunables.list
+++ b/sysdeps/x86/dl-tunables.list
@@ -21,6 +21,12 @@ glibc {
hwcaps {
type: STRING
}
+ x86_ibt {
+ type: STRING
+ }
+ x86_shstk {
+ type: STRING
+ }
x86_non_temporal_threshold {
type: SIZE_T
}
diff --git a/sysdeps/x86/libc-start.h b/sysdeps/x86/libc-start.h
new file mode 100644
index 0000000000..6f44262bf4
--- /dev/null
+++ b/sysdeps/x86/libc-start.h
@@ -0,0 +1,25 @@
+/* X86 definitions for libc main startup.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef SHARED
+# define ARCH_SETUP_IREL() apply_irel ()
+# define ARCH_APPLY_IREL()
+# ifndef ARCH_SETUP_TLS
+# define ARCH_SETUP_TLS() __libc_setup_tls ()
+# endif
+#endif /* !SHARED */
diff --git a/sysdeps/x86/link_map.h b/sysdeps/x86/link_map.h
new file mode 100644
index 0000000000..ef1206a9d2
--- /dev/null
+++ b/sysdeps/x86/link_map.h
@@ -0,0 +1,26 @@
+/* Additional fields in struct link_map. Linux/x86 version.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+/* If this object is enabled with CET. */
+enum
+ {
+ lc_none = 0, /* Not enabled with CET. */
+ lc_ibt = 1 << 0, /* Enabled with IBT. */
+ lc_shstk = 1 << 1, /* Enabled with STSHK. */
+ lc_ibt_and_shstk = lc_ibt | lc_shstk /* Enabled with both. */
+ } l_cet:2;
diff --git a/sysdeps/x86/sysdep.h b/sysdeps/x86/sysdep.h
index afcb7cfd76..9843d9dff7 100644
--- a/sysdeps/x86/sysdep.h
+++ b/sysdeps/x86/sysdep.h
@@ -25,6 +25,13 @@
/* Syntactic details of assembler. */
+#ifdef _CET_ENDBR
+# define _CET_NOTRACK notrack
+#else
+# define _CET_ENDBR
+# define _CET_NOTRACK
+#endif
+
/* ELF uses byte-counts for .align, most others use log2 of count of bytes. */
#define ALIGNARG(log2) 1<<log2
#define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
@@ -36,6 +43,7 @@
.align ALIGNARG(4); \
C_LABEL(name) \
cfi_startproc; \
+ _CET_ENDBR; \
CALL_MCOUNT
#undef END
diff --git a/sysdeps/x86_64/dl-trampoline.h b/sysdeps/x86_64/dl-trampoline.h
index 298cfb3d99..a28b1e73a4 100644
--- a/sysdeps/x86_64/dl-trampoline.h
+++ b/sysdeps/x86_64/dl-trampoline.h
@@ -64,6 +64,7 @@
cfi_startproc
_dl_runtime_resolve:
cfi_adjust_cfa_offset(16) # Incorporate PLT
+ _CET_ENDBR
# if DL_RUNTIME_RESOLVE_REALIGN_STACK
# if LOCAL_STORAGE_AREA != 8
# error LOCAL_STORAGE_AREA must be 8
@@ -168,6 +169,7 @@ _dl_runtime_resolve:
_dl_runtime_profile:
cfi_startproc
cfi_adjust_cfa_offset(16) # Incorporate PLT
+ _CET_ENDBR
/* The La_x86_64_regs data structure pointed to by the
fourth paramater must be VEC_SIZE-byte aligned. This must
be explicitly enforced. We have the set up a dynamically
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread
* [PATCH 20/24] i386: Use _CET_NOTRACK in strcpy-sse2.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (8 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 03/24] x86: Support IBT and SHSTK in Intel CET [BZ #21598] H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-06-13 15:32 ` [PATCH 06/24] x86-64: Add _CET_ENDBR to STRCMP_SSE42 H.J. Lu
` (14 subsequent siblings)
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
* sysdeps/i386/i686/multiarch/strcpy-sse2.S
(BRANCH_TO_JMPTBL_ENTRY): Add _CET_NOTRACK before indirect jump
to jump table.
---
sysdeps/i386/i686/multiarch/strcpy-sse2.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/sysdeps/i386/i686/multiarch/strcpy-sse2.S b/sysdeps/i386/i686/multiarch/strcpy-sse2.S
index 64bdb91df4..3fc27d93d4 100644
--- a/sysdeps/i386/i686/multiarch/strcpy-sse2.S
+++ b/sysdeps/i386/i686/multiarch/strcpy-sse2.S
@@ -65,7 +65,7 @@
absolute address. */ \
addl (%ecx,INDEX,SCALE), %ecx; \
/* We loaded the jump table and adjusted ECX. Go. */ \
- jmp *%ecx
+ _CET_NOTRACK jmp *%ecx
# else
# define JMPTBL(I, B) I
@@ -74,7 +74,7 @@
jump table. SCALE is the scale of INDEX. */
# define BRANCH_TO_JMPTBL_ENTRY(TABLE, INDEX, SCALE) \
- jmp *TABLE(,INDEX,SCALE)
+ _CET_NOTRACK jmp *TABLE(,INDEX,SCALE)
# endif
.text
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* [PATCH 06/24] x86-64: Add _CET_ENDBR to STRCMP_SSE42
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (9 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 20/24] i386: Use _CET_NOTRACK in strcpy-sse2.S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-07-06 14:50 ` Carlos O'Donell
2018-06-13 15:32 ` [PATCH 10/24] x86-64: Use _CET_NOTRACK in strcpy-sse2-unaligned.S H.J. Lu
` (13 subsequent siblings)
24 siblings, 1 reply; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
Add _CET_ENDBR to STRCMP_SSE42, which is called indirectly, to support
IBT.
* sysdeps/x86_64/multiarch/strcmp-sse42.S (STRCMP_SSE42): Add
_CET_ENDBR.
---
sysdeps/x86_64/multiarch/strcmp-sse42.S | 1 +
1 file changed, 1 insertion(+)
diff --git a/sysdeps/x86_64/multiarch/strcmp-sse42.S b/sysdeps/x86_64/multiarch/strcmp-sse42.S
index 6fa0c2c7d2..5a0c6668a7 100644
--- a/sysdeps/x86_64/multiarch/strcmp-sse42.S
+++ b/sysdeps/x86_64/multiarch/strcmp-sse42.S
@@ -126,6 +126,7 @@ END (GLABEL(__strncasecmp))
STRCMP_SSE42:
cfi_startproc
+ _CET_ENDBR
CALL_MCOUNT
/*
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* Re: [PATCH 06/24] x86-64: Add _CET_ENDBR to STRCMP_SSE42
2018-06-13 15:32 ` [PATCH 06/24] x86-64: Add _CET_ENDBR to STRCMP_SSE42 H.J. Lu
@ 2018-07-06 14:50 ` Carlos O'Donell
0 siblings, 0 replies; 54+ messages in thread
From: Carlos O'Donell @ 2018-07-06 14:50 UTC (permalink / raw)
To: H.J. Lu, libc-alpha
On 06/13/2018 11:31 AM, H.J. Lu wrote:
> Add _CET_ENDBR to STRCMP_SSE42, which is called indirectly, to support
> IBT.
>
> * sysdeps/x86_64/multiarch/strcmp-sse42.S (STRCMP_SSE42): Add
> _CET_ENDBR.
Please commit.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
> ---
> sysdeps/x86_64/multiarch/strcmp-sse42.S | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/sysdeps/x86_64/multiarch/strcmp-sse42.S b/sysdeps/x86_64/multiarch/strcmp-sse42.S
> index 6fa0c2c7d2..5a0c6668a7 100644
> --- a/sysdeps/x86_64/multiarch/strcmp-sse42.S
> +++ b/sysdeps/x86_64/multiarch/strcmp-sse42.S
> @@ -126,6 +126,7 @@ END (GLABEL(__strncasecmp))
>
> STRCMP_SSE42:
> cfi_startproc
> + _CET_ENDBR
> CALL_MCOUNT
>
> /*
>
--
Cheers,
Carlos.
^ permalink raw reply [flat|nested] 54+ messages in thread
* [PATCH 10/24] x86-64: Use _CET_NOTRACK in strcpy-sse2-unaligned.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (10 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 06/24] x86-64: Add _CET_ENDBR to STRCMP_SSE42 H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-06-13 15:32 ` [PATCH 01/24] x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563] H.J. Lu
` (12 subsequent siblings)
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
* sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S
(BRANCH_TO_JMPTBL_ENTRY): Add _CET_NOTRACK before indirect jump
to jump table.
---
sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S b/sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S
index 56b748eb2c..72bf7e8586 100644
--- a/sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S
+++ b/sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S
@@ -33,7 +33,7 @@
lea TABLE(%rip), %r11; \
movslq (%r11, INDEX, SCALE), %rcx; \
lea (%r11, %rcx), %rcx; \
- jmp *%rcx
+ _CET_NOTRACK jmp *%rcx
# ifndef USE_AS_STRCAT
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* [PATCH 01/24] x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563]
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (11 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 10/24] x86-64: Use _CET_NOTRACK in strcpy-sse2-unaligned.S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-07-13 13:19 ` V2: " H.J. Lu
2018-06-13 15:32 ` [PATCH 21/24] i386: Use _CET_NOTRACK in strcat-sse2.S H.J. Lu
` (11 subsequent siblings)
24 siblings, 1 reply; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
This will be used by CET run-time control.
[BZ #22563]
* nptl/pthread_create.c (__pthread_create_2_1): Use
THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
* sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
* sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
Likewise.
* sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
to feature_1.
* sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
* sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
---
nptl/pthread_create.c | 5 +++++
sysdeps/i386/nptl/tcb-offsets.sym | 1 +
sysdeps/i386/nptl/tls.h | 5 ++++-
sysdeps/unix/sysv/linux/x86/pthreaddef.h | 24 ++++++++++++++++++++++++
sysdeps/x86_64/nptl/tcb-offsets.sym | 1 +
sysdeps/x86_64/nptl/tls.h | 5 ++++-
6 files changed, 39 insertions(+), 2 deletions(-)
create mode 100644 sysdeps/unix/sysv/linux/x86/pthreaddef.h
diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c
index 92c945b12b..16998f4bbd 100644
--- a/nptl/pthread_create.c
+++ b/nptl/pthread_create.c
@@ -712,6 +712,11 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr,
THREAD_COPY_POINTER_GUARD (pd);
#endif
+ /* Copy additonal info. */
+#ifdef THREAD_COPY_ADDITONAL_INFO
+ THREAD_COPY_ADDITONAL_INFO (pd);
+#endif
+
/* Verify the sysinfo bits were copied in allocate_stack if needed. */
#ifdef NEED_DL_SYSINFO
CHECK_THREAD_SYSINFO (pd);
diff --git a/sysdeps/i386/nptl/tcb-offsets.sym b/sysdeps/i386/nptl/tcb-offsets.sym
index 7d7fe5e71c..fbac241c45 100644
--- a/sysdeps/i386/nptl/tcb-offsets.sym
+++ b/sysdeps/i386/nptl/tcb-offsets.sym
@@ -12,3 +12,4 @@ CLEANUP offsetof (struct pthread, cleanup)
CLEANUP_PREV offsetof (struct _pthread_cleanup_buffer, __prev)
MUTEX_FUTEX offsetof (pthread_mutex_t, __data.__lock)
POINTER_GUARD offsetof (tcbhead_t, pointer_guard)
+FEATURE_1_OFFSET offsetof (tcbhead_t, feature_1)
diff --git a/sysdeps/i386/nptl/tls.h b/sysdeps/i386/nptl/tls.h
index afb71ce431..9535c01905 100644
--- a/sysdeps/i386/nptl/tls.h
+++ b/sysdeps/i386/nptl/tls.h
@@ -41,7 +41,10 @@ typedef struct
uintptr_t stack_guard;
uintptr_t pointer_guard;
int gscope_flag;
- int __glibc_reserved1;
+ /* Bit 0: IBT.
+ Bit 1: SHSTK.
+ */
+ unsigned int feature_1;
/* Reservation of some values for the TM ABI. */
void *__private_tm[3];
/* GCC split stack support. */
diff --git a/sysdeps/unix/sysv/linux/x86/pthreaddef.h b/sysdeps/unix/sysv/linux/x86/pthreaddef.h
new file mode 100644
index 0000000000..539f6540d0
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/pthreaddef.h
@@ -0,0 +1,24 @@
+/* Pthread macros. Linux/x86 version.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include_next <pthreaddef.h>
+
+/* Wee need to copy feature_1 in pthread_create. */
+#define THREAD_COPY_ADDITONAL_INFO(descr) \
+ ((descr)->header.feature_1 \
+ = THREAD_GETMEM (THREAD_SELF, header.feature_1))
diff --git a/sysdeps/x86_64/nptl/tcb-offsets.sym b/sysdeps/x86_64/nptl/tcb-offsets.sym
index be63404a16..387621e88c 100644
--- a/sysdeps/x86_64/nptl/tcb-offsets.sym
+++ b/sysdeps/x86_64/nptl/tcb-offsets.sym
@@ -12,6 +12,7 @@ MUTEX_FUTEX offsetof (pthread_mutex_t, __data.__lock)
MULTIPLE_THREADS_OFFSET offsetof (tcbhead_t, multiple_threads)
POINTER_GUARD offsetof (tcbhead_t, pointer_guard)
VGETCPU_CACHE_OFFSET offsetof (tcbhead_t, vgetcpu_cache)
+FEATURE_1_OFFSET offsetof (tcbhead_t, feature_1)
-- Not strictly offsets, but these values are also used in the TCB.
TCB_CANCELSTATE_BITMASK CANCELSTATE_BITMASK
diff --git a/sysdeps/x86_64/nptl/tls.h b/sysdeps/x86_64/nptl/tls.h
index 65c0051dcf..6557c80ffd 100644
--- a/sysdeps/x86_64/nptl/tls.h
+++ b/sysdeps/x86_64/nptl/tls.h
@@ -51,7 +51,10 @@ typedef struct
uintptr_t stack_guard;
uintptr_t pointer_guard;
unsigned long int vgetcpu_cache[2];
- int __glibc_reserved1;
+ /* Bit 0: IBT.
+ Bit 1: SHSTK.
+ */
+ unsigned int feature_1;
int __glibc_unused1;
/* Reservation of some values for the TM ABI. */
void *__private_tm[4];
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* V2: [PATCH 01/24] x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563]
2018-06-13 15:32 ` [PATCH 01/24] x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563] H.J. Lu
@ 2018-07-13 13:19 ` H.J. Lu
2018-07-13 18:51 ` Carlos O'Donell
0 siblings, 1 reply; 54+ messages in thread
From: H.J. Lu @ 2018-07-13 13:19 UTC (permalink / raw)
To: libc-alpha
On Wed, Jun 13, 2018 at 08:31:44AM -0700, H.J. Lu wrote:
> This will be used by CET run-time control.
>
> [BZ #22563]
> * nptl/pthread_create.c (__pthread_create_2_1): Use
> THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
> * sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
> * sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
> Likewise.
> * sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
> to feature_1.
> * sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
> * sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
Here is the updated patch to add feature_1 to tcbhead_t and
introduce macros for CET enabling. OK for master?
H.J.
----
feature_1 has X86_FEATURE_1_IBT and X86_FEATURE_1_SHSTK bits for CET
run-time control.
CET_ENABLED, IBT_ENABLED and SHSTK_ENABLED are defined to 1 or 0 to
indicate that if CET, IBT and SHSTK are enabled.
[BZ #22563]
* nptl/pthread_create.c (__pthread_create_2_1): Use
THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
* sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
* sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
Likewise.
* sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
to feature_1.
* sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
* sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
* sysdeps/x86/sysdep.h (X86_FEATURE_1_IBT): New.
(X86_FEATURE_1_SHSTK): Likewise.
(CET_ENABLED): Likewise.
(IBT_ENABLED): Likewise.
(SHSTK_ENABLED): Likewise.
---
nptl/pthread_create.c | 5 +++++
sysdeps/i386/nptl/tcb-offsets.sym | 1 +
sysdeps/i386/nptl/tls.h | 5 ++++-
sysdeps/unix/sysv/linux/x86/pthreaddef.h | 24 +++++++++++++++++++++
sysdeps/x86/sysdep.h | 27 ++++++++++++++++++++++++
sysdeps/x86_64/nptl/tcb-offsets.sym | 1 +
sysdeps/x86_64/nptl/tls.h | 5 ++++-
7 files changed, 66 insertions(+), 2 deletions(-)
create mode 100644 sysdeps/unix/sysv/linux/x86/pthreaddef.h
diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c
index 92c945b12b..16998f4bbd 100644
--- a/nptl/pthread_create.c
+++ b/nptl/pthread_create.c
@@ -712,6 +712,11 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr,
THREAD_COPY_POINTER_GUARD (pd);
#endif
+ /* Copy additonal info. */
+#ifdef THREAD_COPY_ADDITONAL_INFO
+ THREAD_COPY_ADDITONAL_INFO (pd);
+#endif
+
/* Verify the sysinfo bits were copied in allocate_stack if needed. */
#ifdef NEED_DL_SYSINFO
CHECK_THREAD_SYSINFO (pd);
diff --git a/sysdeps/i386/nptl/tcb-offsets.sym b/sysdeps/i386/nptl/tcb-offsets.sym
index 7d7fe5e71c..fbac241c45 100644
--- a/sysdeps/i386/nptl/tcb-offsets.sym
+++ b/sysdeps/i386/nptl/tcb-offsets.sym
@@ -12,3 +12,4 @@ CLEANUP offsetof (struct pthread, cleanup)
CLEANUP_PREV offsetof (struct _pthread_cleanup_buffer, __prev)
MUTEX_FUTEX offsetof (pthread_mutex_t, __data.__lock)
POINTER_GUARD offsetof (tcbhead_t, pointer_guard)
+FEATURE_1_OFFSET offsetof (tcbhead_t, feature_1)
diff --git a/sysdeps/i386/nptl/tls.h b/sysdeps/i386/nptl/tls.h
index afb71ce431..21e23cd809 100644
--- a/sysdeps/i386/nptl/tls.h
+++ b/sysdeps/i386/nptl/tls.h
@@ -41,7 +41,10 @@ typedef struct
uintptr_t stack_guard;
uintptr_t pointer_guard;
int gscope_flag;
- int __glibc_reserved1;
+ /* Bit 0: X86_FEATURE_1_IBT.
+ Bit 1: X86_FEATURE_1_SHSTK.
+ */
+ unsigned int feature_1;
/* Reservation of some values for the TM ABI. */
void *__private_tm[3];
/* GCC split stack support. */
diff --git a/sysdeps/unix/sysv/linux/x86/pthreaddef.h b/sysdeps/unix/sysv/linux/x86/pthreaddef.h
new file mode 100644
index 0000000000..539f6540d0
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/pthreaddef.h
@@ -0,0 +1,24 @@
+/* Pthread macros. Linux/x86 version.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include_next <pthreaddef.h>
+
+/* Wee need to copy feature_1 in pthread_create. */
+#define THREAD_COPY_ADDITONAL_INFO(descr) \
+ ((descr)->header.feature_1 \
+ = THREAD_GETMEM (THREAD_SELF, header.feature_1))
diff --git a/sysdeps/x86/sysdep.h b/sysdeps/x86/sysdep.h
index afcb7cfd76..976566aa37 100644
--- a/sysdeps/x86/sysdep.h
+++ b/sysdeps/x86/sysdep.h
@@ -21,6 +21,33 @@
#include <sysdeps/generic/sysdep.h>
+/* __CET__ is defined by GCC with Control-Flow Protection values:
+
+enum cf_protection_level
+{
+ CF_NONE = 0,
+ CF_BRANCH = 1 << 0,
+ CF_RETURN = 1 << 1,
+ CF_FULL = CF_BRANCH | CF_RETURN,
+ CF_SET = 1 << 2
+};
+*/
+
+/* Set if CF_BRANCH (IBT) is enabled. */
+#define X86_FEATURE_1_IBT (1U << 0)
+/* Set if CF_RETURN (SHSTK) is enabled. */
+#define X86_FEATURE_1_SHSTK (1U << 1)
+
+#ifdef __CET__
+# define CET_ENABLED 1
+# define IBT_ENABLED (__CET__ & X86_FEATURE_1_IBT)
+# define SHSTK_ENABLED (__CET__ & X86_FEATURE_1_SHSTK)
+#else
+# define CET_ENABLED 0
+# define IBT_ENABLED 0
+# define SHSTK_ENABLED 0
+#endif
+
#ifdef __ASSEMBLER__
/* Syntactic details of assembler. */
diff --git a/sysdeps/x86_64/nptl/tcb-offsets.sym b/sysdeps/x86_64/nptl/tcb-offsets.sym
index be63404a16..387621e88c 100644
--- a/sysdeps/x86_64/nptl/tcb-offsets.sym
+++ b/sysdeps/x86_64/nptl/tcb-offsets.sym
@@ -12,6 +12,7 @@ MUTEX_FUTEX offsetof (pthread_mutex_t, __data.__lock)
MULTIPLE_THREADS_OFFSET offsetof (tcbhead_t, multiple_threads)
POINTER_GUARD offsetof (tcbhead_t, pointer_guard)
VGETCPU_CACHE_OFFSET offsetof (tcbhead_t, vgetcpu_cache)
+FEATURE_1_OFFSET offsetof (tcbhead_t, feature_1)
-- Not strictly offsets, but these values are also used in the TCB.
TCB_CANCELSTATE_BITMASK CANCELSTATE_BITMASK
diff --git a/sysdeps/x86_64/nptl/tls.h b/sysdeps/x86_64/nptl/tls.h
index 65c0051dcf..f042a0250a 100644
--- a/sysdeps/x86_64/nptl/tls.h
+++ b/sysdeps/x86_64/nptl/tls.h
@@ -51,7 +51,10 @@ typedef struct
uintptr_t stack_guard;
uintptr_t pointer_guard;
unsigned long int vgetcpu_cache[2];
- int __glibc_reserved1;
+ /* Bit 0: X86_FEATURE_1_IBT.
+ Bit 1: X86_FEATURE_1_SHSTK.
+ */
+ unsigned int feature_1;
int __glibc_unused1;
/* Reservation of some values for the TM ABI. */
void *__private_tm[4];
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* Re: V2: [PATCH 01/24] x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563]
2018-07-13 13:19 ` V2: " H.J. Lu
@ 2018-07-13 18:51 ` Carlos O'Donell
2018-07-13 18:55 ` Jeff Law
0 siblings, 1 reply; 54+ messages in thread
From: Carlos O'Donell @ 2018-07-13 18:51 UTC (permalink / raw)
To: H.J. Lu, libc-alpha
On 07/13/2018 09:19 AM, H.J. Lu wrote:
> On Wed, Jun 13, 2018 at 08:31:44AM -0700, H.J. Lu wrote:
>> This will be used by CET run-time control.
>>
>> [BZ #22563]
>> * nptl/pthread_create.c (__pthread_create_2_1): Use
>> THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
>> * sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
>> * sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
>> Likewise.
>> * sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
>> to feature_1.
>> * sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
>> * sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
>
> Here is the updated patch to add feature_1 to tcbhead_t and
> introduce macros for CET enabling. OK for master?
Fix the typo-prone macro API and post a v3 please.
Thank you.
>
> H.J.
> ----
> feature_1 has X86_FEATURE_1_IBT and X86_FEATURE_1_SHSTK bits for CET
> run-time control.
>
> CET_ENABLED, IBT_ENABLED and SHSTK_ENABLED are defined to 1 or 0 to
> indicate that if CET, IBT and SHSTK are enabled.
OK.
>
> [BZ #22563]
> * nptl/pthread_create.c (__pthread_create_2_1): Use
> THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
> * sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
> * sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
> Likewise.
> * sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
> to feature_1.
> * sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
> * sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
> * sysdeps/x86/sysdep.h (X86_FEATURE_1_IBT): New.
> (X86_FEATURE_1_SHSTK): Likewise.
> (CET_ENABLED): Likewise.
> (IBT_ENABLED): Likewise.
> (SHSTK_ENABLED): Likewise.
> ---
> nptl/pthread_create.c | 5 +++++
> sysdeps/i386/nptl/tcb-offsets.sym | 1 +
> sysdeps/i386/nptl/tls.h | 5 ++++-
> sysdeps/unix/sysv/linux/x86/pthreaddef.h | 24 +++++++++++++++++++++
> sysdeps/x86/sysdep.h | 27 ++++++++++++++++++++++++
> sysdeps/x86_64/nptl/tcb-offsets.sym | 1 +
> sysdeps/x86_64/nptl/tls.h | 5 ++++-
> 7 files changed, 66 insertions(+), 2 deletions(-)
> create mode 100644 sysdeps/unix/sysv/linux/x86/pthreaddef.h
>
> diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c
> index 92c945b12b..16998f4bbd 100644
> --- a/nptl/pthread_create.c
> +++ b/nptl/pthread_create.c
> @@ -712,6 +712,11 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr,
> THREAD_COPY_POINTER_GUARD (pd);
> #endif
>
> + /* Copy additonal info. */
> +#ifdef THREAD_COPY_ADDITONAL_INFO
> + THREAD_COPY_ADDITONAL_INFO (pd);
> +#endif
This is a typo-prone macro API.
Please find a way to define this unconditionally.
> +
> /* Verify the sysinfo bits were copied in allocate_stack if needed. */
> #ifdef NEED_DL_SYSINFO
> CHECK_THREAD_SYSINFO (pd);
> diff --git a/sysdeps/i386/nptl/tcb-offsets.sym b/sysdeps/i386/nptl/tcb-offsets.sym
> index 7d7fe5e71c..fbac241c45 100644
> --- a/sysdeps/i386/nptl/tcb-offsets.sym
> +++ b/sysdeps/i386/nptl/tcb-offsets.sym
> @@ -12,3 +12,4 @@ CLEANUP offsetof (struct pthread, cleanup)
> CLEANUP_PREV offsetof (struct _pthread_cleanup_buffer, __prev)
> MUTEX_FUTEX offsetof (pthread_mutex_t, __data.__lock)
> POINTER_GUARD offsetof (tcbhead_t, pointer_guard)
> +FEATURE_1_OFFSET offsetof (tcbhead_t, feature_1)
> diff --git a/sysdeps/i386/nptl/tls.h b/sysdeps/i386/nptl/tls.h
> index afb71ce431..21e23cd809 100644
> --- a/sysdeps/i386/nptl/tls.h
> +++ b/sysdeps/i386/nptl/tls.h
> @@ -41,7 +41,10 @@ typedef struct
> uintptr_t stack_guard;
> uintptr_t pointer_guard;
> int gscope_flag;
> - int __glibc_reserved1;
> + /* Bit 0: X86_FEATURE_1_IBT.
> + Bit 1: X86_FEATURE_1_SHSTK.
> + */
> + unsigned int feature_1;
OK.
> /* Reservation of some values for the TM ABI. */
> void *__private_tm[3];
> /* GCC split stack support. */
> diff --git a/sysdeps/unix/sysv/linux/x86/pthreaddef.h b/sysdeps/unix/sysv/linux/x86/pthreaddef.h
> new file mode 100644
> index 0000000000..539f6540d0
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/x86/pthreaddef.h
> @@ -0,0 +1,24 @@
> +/* Pthread macros. Linux/x86 version.
> + Copyright (C) 2018 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <http://www.gnu.org/licenses/>. */
> +
> +#include_next <pthreaddef.h>
> +
> +/* Wee need to copy feature_1 in pthread_create. */
> +#define THREAD_COPY_ADDITONAL_INFO(descr) \
> + ((descr)->header.feature_1 \
> + = THREAD_GETMEM (THREAD_SELF, header.feature_1))
OK.
> diff --git a/sysdeps/x86/sysdep.h b/sysdeps/x86/sysdep.h
> index afcb7cfd76..976566aa37 100644
> --- a/sysdeps/x86/sysdep.h
> +++ b/sysdeps/x86/sysdep.h
> @@ -21,6 +21,33 @@
>
> #include <sysdeps/generic/sysdep.h>
>
> +/* __CET__ is defined by GCC with Control-Flow Protection values:
> +
> +enum cf_protection_level
> +{
> + CF_NONE = 0,
> + CF_BRANCH = 1 << 0,
> + CF_RETURN = 1 << 1,
> + CF_FULL = CF_BRANCH | CF_RETURN,
> + CF_SET = 1 << 2
> +};
> +*/
> +
> +/* Set if CF_BRANCH (IBT) is enabled. */
> +#define X86_FEATURE_1_IBT (1U << 0)
OK. Thanks for defining this, it makes the assembly easier to read.
> +/* Set if CF_RETURN (SHSTK) is enabled. */
> +#define X86_FEATURE_1_SHSTK (1U << 1)
OK.
> +
> +#ifdef __CET__
> +# define CET_ENABLED 1
> +# define IBT_ENABLED (__CET__ & X86_FEATURE_1_IBT)
> +# define SHSTK_ENABLED (__CET__ & X86_FEATURE_1_SHSTK)
> +#else
> +# define CET_ENABLED 0
> +# define IBT_ENABLED 0
> +# define SHSTK_ENABLED 0
> +#endif
> +
> #ifdef __ASSEMBLER__
>
> /* Syntactic details of assembler. */
> diff --git a/sysdeps/x86_64/nptl/tcb-offsets.sym b/sysdeps/x86_64/nptl/tcb-offsets.sym
> index be63404a16..387621e88c 100644
> --- a/sysdeps/x86_64/nptl/tcb-offsets.sym
> +++ b/sysdeps/x86_64/nptl/tcb-offsets.sym
> @@ -12,6 +12,7 @@ MUTEX_FUTEX offsetof (pthread_mutex_t, __data.__lock)
> MULTIPLE_THREADS_OFFSET offsetof (tcbhead_t, multiple_threads)
> POINTER_GUARD offsetof (tcbhead_t, pointer_guard)
> VGETCPU_CACHE_OFFSET offsetof (tcbhead_t, vgetcpu_cache)
> +FEATURE_1_OFFSET offsetof (tcbhead_t, feature_1)
OK.
>
> -- Not strictly offsets, but these values are also used in the TCB.
> TCB_CANCELSTATE_BITMASK CANCELSTATE_BITMASK
> diff --git a/sysdeps/x86_64/nptl/tls.h b/sysdeps/x86_64/nptl/tls.h
> index 65c0051dcf..f042a0250a 100644
> --- a/sysdeps/x86_64/nptl/tls.h
> +++ b/sysdeps/x86_64/nptl/tls.h
> @@ -51,7 +51,10 @@ typedef struct
> uintptr_t stack_guard;
> uintptr_t pointer_guard;
> unsigned long int vgetcpu_cache[2];
> - int __glibc_reserved1;
> + /* Bit 0: X86_FEATURE_1_IBT.
> + Bit 1: X86_FEATURE_1_SHSTK.
> + */
> + unsigned int feature_1;
OK.
> int __glibc_unused1;
> /* Reservation of some values for the TM ABI. */
> void *__private_tm[4];
>
Cheers,
Carlos.
^ permalink raw reply [flat|nested] 54+ messages in thread* Re: V2: [PATCH 01/24] x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563]
2018-07-13 18:51 ` Carlos O'Donell
@ 2018-07-13 18:55 ` Jeff Law
2018-07-13 19:05 ` Carlos O'Donell
0 siblings, 1 reply; 54+ messages in thread
From: Jeff Law @ 2018-07-13 18:55 UTC (permalink / raw)
To: Carlos O'Donell, H.J. Lu, libc-alpha
On 07/13/2018 12:51 PM, Carlos O'Donell wrote:
> On 07/13/2018 09:19 AM, H.J. Lu wrote:
>> On Wed, Jun 13, 2018 at 08:31:44AM -0700, H.J. Lu wrote:
>>> This will be used by CET run-time control.
>>>
>>> [BZ #22563]
>>> * nptl/pthread_create.c (__pthread_create_2_1): Use
>>> THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
>>> * sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
>>> * sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
>>> Likewise.
>>> * sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
>>> to feature_1.
>>> * sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
>>> * sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
>>
>> Here is the updated patch to add feature_1 to tcbhead_t and
>> introduce macros for CET enabling. OK for master?
>
> Fix the typo-prone macro API and post a v3 please.
>
> Thank you.
Umm, has this been tested with the sanitizers? I thought they used that
field.
jeff
^ permalink raw reply [flat|nested] 54+ messages in thread
* Re: V2: [PATCH 01/24] x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563]
2018-07-13 18:55 ` Jeff Law
@ 2018-07-13 19:05 ` Carlos O'Donell
2018-07-13 19:11 ` Jeff Law
0 siblings, 1 reply; 54+ messages in thread
From: Carlos O'Donell @ 2018-07-13 19:05 UTC (permalink / raw)
To: Jeff Law, H.J. Lu, libc-alpha
On 07/13/2018 02:55 PM, Jeff Law wrote:
> On 07/13/2018 12:51 PM, Carlos O'Donell wrote:
>> On 07/13/2018 09:19 AM, H.J. Lu wrote:
>>> On Wed, Jun 13, 2018 at 08:31:44AM -0700, H.J. Lu wrote:
>>>> This will be used by CET run-time control.
>>>>
>>>> [BZ #22563]
>>>> * nptl/pthread_create.c (__pthread_create_2_1): Use
>>>> THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
>>>> * sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
>>>> * sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
>>>> Likewise.
>>>> * sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
>>>> to feature_1.
>>>> * sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
>>>> * sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
>>>
>>> Here is the updated patch to add feature_1 to tcbhead_t and
>>> introduce macros for CET enabling. OK for master?
>>
>> Fix the typo-prone macro API and post a v3 please.
>>
>> Thank you.
> Umm, has this been tested with the sanitizers? I thought they used that
> field.
The size of tcbhead_t has not changed, which is something that might impact
the santiziers.
But now that you mention it, why do I vaguely remember a conversation about
the santizers using the reserved bytes as storage for themselves?
Is that what you are talking about?
HJ, could you look into this please?
I think the sanitizers are not within their rights to use any bytes in the
tcbhead_t structure, particularly reserved bytes. We should coordinate with
them, but that should not stop the acceptance of this patch in 2.28.
Cheers,
Carlos.
^ permalink raw reply [flat|nested] 54+ messages in thread
* Re: V2: [PATCH 01/24] x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563]
2018-07-13 19:05 ` Carlos O'Donell
@ 2018-07-13 19:11 ` Jeff Law
2018-07-13 19:22 ` Florian Weimer
0 siblings, 1 reply; 54+ messages in thread
From: Jeff Law @ 2018-07-13 19:11 UTC (permalink / raw)
To: Carlos O'Donell, H.J. Lu, libc-alpha
On 07/13/2018 01:05 PM, Carlos O'Donell wrote:
> On 07/13/2018 02:55 PM, Jeff Law wrote:
>> On 07/13/2018 12:51 PM, Carlos O'Donell wrote:
>>> On 07/13/2018 09:19 AM, H.J. Lu wrote:
>>>> On Wed, Jun 13, 2018 at 08:31:44AM -0700, H.J. Lu wrote:
>>>>> This will be used by CET run-time control.
>>>>>
>>>>> [BZ #22563]
>>>>> * nptl/pthread_create.c (__pthread_create_2_1): Use
>>>>> THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
>>>>> * sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
>>>>> * sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
>>>>> Likewise.
>>>>> * sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
>>>>> to feature_1.
>>>>> * sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
>>>>> * sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
>>>>
>>>> Here is the updated patch to add feature_1 to tcbhead_t and
>>>> introduce macros for CET enabling. OK for master?
>>>
>>> Fix the typo-prone macro API and post a v3 please.
>>>
>>> Thank you.
>> Umm, has this been tested with the sanitizers? I thought they used that
>> field.
>
> The size of tcbhead_t has not changed, which is something that might impact
> the santiziers.
>
> But now that you mention it, why do I vaguely remember a conversation about
> the santizers using the reserved bytes as storage for themselves?
>
> Is that what you are talking about?
>
> HJ, could you look into this please?
>
> I think the sanitizers are not within their rights to use any bytes in the
> tcbhead_t structure, particularly reserved bytes. We should coordinate with
> them, but that should not stop the acceptance of this patch in 2.28.
sanitizer_common/sanitizer_linux.cc:
static bool Aarch64GetESR(ucontext_t *ucontext, u64 *esr) {
static const u32 kEsrMagic = 0x45535201;
u8 *aux = ucontext->uc_mcontext.__reserved;
while (true) {
_aarch64_ctx *ctx = (_aarch64_ctx *)aux;
if (ctx->size == 0) break;
if (ctx->magic == kEsrMagic) {
*esr = ((__sanitizer_esr_context *)ctx)->esr;
return true;
}
aux += ctx->size;
}
return false;
}
It's seriously lame that they're abusing the reserved field like that...
I see that HJ is just changing x86, so we may be OK here since the
sanitizer code in question is aarch64 specific.
Jeff
^ permalink raw reply [flat|nested] 54+ messages in thread* Re: V2: [PATCH 01/24] x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563]
2018-07-13 19:11 ` Jeff Law
@ 2018-07-13 19:22 ` Florian Weimer
2018-07-13 20:21 ` Carlos O'Donell
0 siblings, 1 reply; 54+ messages in thread
From: Florian Weimer @ 2018-07-13 19:22 UTC (permalink / raw)
To: Jeff Law; +Cc: Carlos O'Donell, H.J. Lu, libc-alpha
* Jeff Law:
> On 07/13/2018 01:05 PM, Carlos O'Donell wrote:
>> I think the sanitizers are not within their rights to use any bytes in the
>> tcbhead_t structure, particularly reserved bytes. We should coordinate with
>> them, but that should not stop the acceptance of this patch in 2.28.
> sanitizer_common/sanitizer_linux.cc:
>
> static bool Aarch64GetESR(ucontext_t *ucontext, u64 *esr) {
> static const u32 kEsrMagic = 0x45535201;
> u8 *aux = ucontext->uc_mcontext.__reserved;
> while (true) {
> _aarch64_ctx *ctx = (_aarch64_ctx *)aux;
> if (ctx->size == 0) break;
> if (ctx->magic == kEsrMagic) {
> *esr = ((__sanitizer_esr_context *)ctx)->esr;
> return true;
> }
> aux += ctx->size;
> }
> return false;
> }
>
> It's seriously lame that they're abusing the reserved field like that...
In this case, __reserved doesn't mean “reserved for future use”, but
“reserved as an allocation area for the kernel for dynamically sized
data structures”. This is part of the kernel/userspace API.
^ permalink raw reply [flat|nested] 54+ messages in thread* Re: V2: [PATCH 01/24] x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563]
2018-07-13 19:22 ` Florian Weimer
@ 2018-07-13 20:21 ` Carlos O'Donell
0 siblings, 0 replies; 54+ messages in thread
From: Carlos O'Donell @ 2018-07-13 20:21 UTC (permalink / raw)
To: Florian Weimer, Jeff Law; +Cc: H.J. Lu, libc-alpha
On 07/13/2018 03:16 PM, Florian Weimer wrote:
> * Jeff Law:
>
>> On 07/13/2018 01:05 PM, Carlos O'Donell wrote:
>>> I think the sanitizers are not within their rights to use any bytes in the
>>> tcbhead_t structure, particularly reserved bytes. We should coordinate with
>>> them, but that should not stop the acceptance of this patch in 2.28.
>> sanitizer_common/sanitizer_linux.cc:
>>
>> static bool Aarch64GetESR(ucontext_t *ucontext, u64 *esr) {
>> static const u32 kEsrMagic = 0x45535201;
>> u8 *aux = ucontext->uc_mcontext.__reserved;
>> while (true) {
>> _aarch64_ctx *ctx = (_aarch64_ctx *)aux;
>> if (ctx->size == 0) break;
>> if (ctx->magic == kEsrMagic) {
>> *esr = ((__sanitizer_esr_context *)ctx)->esr;
>> return true;
>> }
>> aux += ctx->size;
>> }
>> return false;
>> }
>>
>> It's seriously lame that they're abusing the reserved field like that...
>
> In this case, __reserved doesn't mean “reserved for future useâ€, but
> “reserved as an allocation area for the kernel for dynamically sized
> data structuresâ€. This is part of the kernel/userspace API.
Right, and this isn't in the tcbhead_t structure either, this is the
on-stack uc_mcontext.
Cheers,
Carlos.
^ permalink raw reply [flat|nested] 54+ messages in thread
* [PATCH 21/24] i386: Use _CET_NOTRACK in strcat-sse2.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (12 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 01/24] x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563] H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-06-13 15:32 ` [PATCH 16/24] i386: Use _CET_NOTRACK in memset-sse2.S H.J. Lu
` (10 subsequent siblings)
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
* sysdeps/i386/i686/multiarch/strcat-sse2.S
(BRANCH_TO_JMPTBL_ENTRY): Add _CET_NOTRACK before indirect jump
to jump table.
---
sysdeps/i386/i686/multiarch/strcat-sse2.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/sysdeps/i386/i686/multiarch/strcat-sse2.S b/sysdeps/i386/i686/multiarch/strcat-sse2.S
index bed0b66225..19d5f5f65d 100644
--- a/sysdeps/i386/i686/multiarch/strcat-sse2.S
+++ b/sysdeps/i386/i686/multiarch/strcat-sse2.S
@@ -50,7 +50,7 @@
absolute address. */ \
addl (%ecx,INDEX,SCALE), %ecx; \
/* We loaded the jump table and adjusted ECX. Go. */ \
- jmp *%ecx
+ _CET_NOTRACK jmp *%ecx
# else
# define JMPTBL(I, B) I
@@ -59,7 +59,7 @@
jump table. SCALE is the scale of INDEX. */
# define BRANCH_TO_JMPTBL_ENTRY(TABLE, INDEX, SCALE) \
- jmp *TABLE(,INDEX,SCALE)
+ _CET_NOTRACK jmp *TABLE(,INDEX,SCALE)
# endif
# ifndef STRCAT
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* [PATCH 16/24] i386: Use _CET_NOTRACK in memset-sse2.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (13 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 21/24] i386: Use _CET_NOTRACK in strcat-sse2.S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-06-13 15:32 ` [PATCH 17/24] i386: Use _CET_NOTRACK in memcmp-sse4.S H.J. Lu
` (9 subsequent siblings)
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
* sysdeps/i386/i686/multiarch/memset-sse2.S
(BRANCH_TO_JMPTBL_ENTRY): Add _CET_NOTRACK before indirect jump
to jump table.
---
sysdeps/i386/i686/multiarch/memset-sse2.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/sysdeps/i386/i686/multiarch/memset-sse2.S b/sysdeps/i386/i686/multiarch/memset-sse2.S
index 8869c80f25..5c9eba1e65 100644
--- a/sysdeps/i386/i686/multiarch/memset-sse2.S
+++ b/sysdeps/i386/i686/multiarch/memset-sse2.S
@@ -63,7 +63,7 @@
add (%ebx,%ecx,4), %ebx; \
add %ecx, %edx; \
/* We loaded the jump table and adjusted EDX. Go. */ \
- jmp *%ebx
+ _CET_NOTRACK jmp *%ebx
#else
# define ENTRANCE
# define RETURN_END ret
@@ -75,7 +75,7 @@
absolute offsets. */
# define BRANCH_TO_JMPTBL_ENTRY(TABLE) \
add %ecx, %edx; \
- jmp *TABLE(,%ecx,4)
+ _CET_NOTRACK jmp *TABLE(,%ecx,4)
#endif
.section .text.sse2,"ax",@progbits
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* [PATCH 17/24] i386: Use _CET_NOTRACK in memcmp-sse4.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (14 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 16/24] i386: Use _CET_NOTRACK in memset-sse2.S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-06-13 15:32 ` [PATCH 02/24] x86: Support shadow stack pointer in setjmp/longjmp H.J. Lu
` (8 subsequent siblings)
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
* sysdeps/i386/i686/multiarch/memcmp-sse4.S
(BRANCH_TO_JMPTBL_ENTRY): Add _CET_NOTRACK before indirect jump
to jump table.
---
sysdeps/i386/i686/multiarch/memcmp-sse4.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/sysdeps/i386/i686/multiarch/memcmp-sse4.S b/sysdeps/i386/i686/multiarch/memcmp-sse4.S
index be37108987..bc2cb2729d 100644
--- a/sysdeps/i386/i686/multiarch/memcmp-sse4.S
+++ b/sysdeps/i386/i686/multiarch/memcmp-sse4.S
@@ -59,7 +59,7 @@
absolute address. */ \
addl (%ebx,INDEX,SCALE), %ebx; \
/* We loaded the jump table and adjusted EDX/ESI. Go. */ \
- jmp *%ebx
+ _CET_NOTRACK jmp *%ebx
# else
# define JMPTBL(I, B) I
@@ -67,7 +67,7 @@
jump table with relative offsets. INDEX is a register contains the
index into the jump table. SCALE is the scale of INDEX. */
# define BRANCH_TO_JMPTBL_ENTRY(TABLE, INDEX, SCALE) \
- jmp *TABLE(,INDEX,SCALE)
+ _CET_NOTRACK jmp *TABLE(,INDEX,SCALE)
# endif
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* [PATCH 02/24] x86: Support shadow stack pointer in setjmp/longjmp
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (15 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 17/24] i386: Use _CET_NOTRACK in memcmp-sse4.S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-07-12 18:13 ` Carlos O'Donell
2018-06-13 15:32 ` [PATCH 04/24] x86: Add _CET_ENDBR to functions in crti.S H.J. Lu
` (7 subsequent siblings)
24 siblings, 1 reply; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
Save and restore shadow stack pointer in setjmp and longjmp to support
shadow stack in Intel CET. Use feature_1 in tcbhead_t to check if
shadow stack is enabled before saving and restoring shadow stack
pointer so that it works with the old smaller cancel_jmp_buf which
doesn't have space for shadow stack pointer.
2017-12-07 Igor Tsimbalist <igor.v.tsimbalist@intel.com>
H.J. Lu <hongjiu.lu@intel.com>
* sysdeps/i386/__longjmp.S: Include <jmp_buf-ssp.h>.
(__longjmp): Restore shadow stack pointer if shadow stack is
enabled, SHADOW_STACK_POINTER_OFFSET is defined and __longjmp
isn't defined for __longjmp_cancel.
* sysdeps/i386/bsd-_setjmp.S: Include <jmp_buf-ssp.h>.
(_setjmp): Save shadow stack pointer if shadow stack is enabled
and SHADOW_STACK_POINTER_OFFSET is defined.
* sysdeps/i386/bsd-setjmp.S: Include <jmp_buf-ssp.h>.
(setjmp): Save shadow stack pointer if shadow stack is enabled
and SHADOW_STACK_POINTER_OFFSET is defined.
* sysdeps/i386/setjmp.S: Include <jmp_buf-ssp.h>.
(__sigsetjmp): Save shadow stack pointer if shadow stack is
enabled and SHADOW_STACK_POINTER_OFFSET is defined.
* sysdeps/unix/sysv/linux/i386/____longjmp_chk.S: Include
<jmp_buf-ssp.h>.
(____longjmp_chk): Restore shadow stack pointer if shadow stack
is enabled and SHADOW_STACK_POINTER_OFFSET is defined.
* sysdeps/unix/sysv/linux/x86/Makefile (gen-as-const-headers):
Remove jmp_buf-ssp.sym.
* sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S: Include
<jmp_buf-ssp.h>.
(____longjmp_chk): Restore shadow stack pointer if shadow stack
is enabled and SHADOW_STACK_POINTER_OFFSET is defined.
* sysdeps/x86/Makefile (gen-as-const-headers): Add
jmp_buf-ssp.sym.
* sysdeps/x86/jmp_buf-ssp.sym: New dummy file.
* sysdeps/x86_64/__longjmp.S: Include <jmp_buf-ssp.h>.
(__longjmp): Restore shadow stack pointer if shadow stack is
enabled, SHADOW_STACK_POINTER_OFFSET is defined and __longjmp
isn't defined for __longjmp_cancel.
* sysdeps/x86_64/setjmp.S: Include <jmp_buf-ssp.h>.
(__sigsetjmp): Save shadow stack pointer if shadow stack is
enabled and SHADOW_STACK_POINTER_OFFSET is defined.
---
sysdeps/i386/__longjmp.S | 78 +++++++++++++++++++
sysdeps/i386/bsd-_setjmp.S | 21 +++++
sysdeps/i386/bsd-setjmp.S | 21 +++++
sysdeps/i386/setjmp.S | 21 +++++
.../unix/sysv/linux/i386/____longjmp_chk.S | 40 ++++++++++
sysdeps/unix/sysv/linux/x86/Makefile | 1 -
.../unix/sysv/linux/x86_64/____longjmp_chk.S | 41 ++++++++++
sysdeps/x86/Makefile | 1 +
sysdeps/x86/jmp_buf-ssp.sym | 1 +
sysdeps/x86_64/__longjmp.S | 45 +++++++++++
sysdeps/x86_64/setjmp.S | 21 +++++
11 files changed, 290 insertions(+), 1 deletion(-)
create mode 100644 sysdeps/x86/jmp_buf-ssp.sym
diff --git a/sysdeps/i386/__longjmp.S b/sysdeps/i386/__longjmp.S
index b38333bead..8b5d7f3d44 100644
--- a/sysdeps/i386/__longjmp.S
+++ b/sysdeps/i386/__longjmp.S
@@ -18,14 +18,57 @@
#include <sysdep.h>
#include <jmpbuf-offsets.h>
+#include <jmp_buf-ssp.h>
#include <asm-syntax.h>
#include <stap-probe.h>
+/* Don't restore shadow stack register if
+ 1. Shadow stack isn't enabled. Or
+ 2. __longjmp is defined for __longjmp_cancel.
+ */
+#if !defined __CET__ || (__CET__ & 2) == 0 || defined __longjmp
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
+
.text
ENTRY (__longjmp)
#ifdef PTR_DEMANGLE
movl 4(%esp), %eax /* User's jmp_buf in %eax. */
+# ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+ /* Check if Shadow Stack is enabled. */
+ testl $(1 << 1), %gs:FEATURE_1_OFFSET
+ jz .Lnoadj
+# else
+ xorl %edx, %edx
+# endif
+ /* Check and adjust the Shadow-Stack-Pointer. */
+ rdsspd %edx
+ /* And compare it with the saved ssp value. */
+ subl SHADOW_STACK_POINTER_OFFSET(%eax), %edx
+ je .Lnoadj
+ /* Count the number of frames to adjust and adjust it
+ with incssp instruction. The instruction can adjust
+ the ssp by [0..255] value only thus use a loop if
+ the number of frames is bigger than 255. */
+ negl %edx
+ shrl $2, %edx
+ /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
+ restoring Shadow-Stack-Pointer of setjmp's caller, we
+ need to unwind shadow stack by one more frame. */
+ addl $1, %edx
+ cmpl $255, %edx
+ jbe .Lonetime
+.Loopadj:
+ incsspd %edx
+ subl $255, %edx
+ cmpl $255, %edx
+ ja .Loopadj
+.Lonetime:
+ incsspd %edx
+.Lnoadj:
+# endif
/* Save the return address now. */
movl (JB_PC*4)(%eax), %edx
/* Get the stack pointer. */
@@ -56,6 +99,41 @@ ENTRY (__longjmp)
#else
movl 4(%esp), %ecx /* User's jmp_buf in %ecx. */
movl 8(%esp), %eax /* Second argument is return value. */
+# ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED
+ /* Check if Shadow Stack is enabled. */
+ testl $(1 << 1), %gs:FEATURE_1_OFFSET
+ jz .Lnoadj
+# endif
+ /* Check and adjust the Shadow-Stack-Pointer. */
+ xorl %edx, %edx
+ /* Get the current ssp. */
+ rdsspd %edx
+ /* And compare it with the saved ssp value. */
+ subl SHADOW_STACK_POINTER_OFFSET(%ecx), %edx
+ je .Lnoadj
+ /* Count the number of frames to adjust and adjust it
+ with incssp instruction. The instruction can adjust
+ the ssp by [0..255] value only thus use a loop if
+ the number of frames is bigger than 255. */
+ negl %edx
+ shrl $2, %edx
+ /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
+ restoring Shadow-Stack-Pointer of setjmp's caller, we
+ need to unwind shadow stack by one more frame. */
+ addl $1, %edx
+ cmpl $255, %edx
+ jbe .Lonetime
+ movl $255, %ebx
+.Loopadj:
+ incsspd %ebx
+ subl $255, %edx
+ cmpl $255, %edx
+ ja .Loopadj
+.Lonetime:
+ incsspd %edx
+.Lnoadj:
+# endif
/* Save the return address now. */
movl (JB_PC*4)(%ecx), %edx
LIBC_PROBE (longjmp, 3, 4@%ecx, -4@%eax, 4@%edx)
diff --git a/sysdeps/i386/bsd-_setjmp.S b/sysdeps/i386/bsd-_setjmp.S
index a626cc6d22..5b09e5dbf8 100644
--- a/sysdeps/i386/bsd-_setjmp.S
+++ b/sysdeps/i386/bsd-_setjmp.S
@@ -22,12 +22,18 @@
#include <sysdep.h>
#include <jmpbuf-offsets.h>
+#include <jmp_buf-ssp.h>
#include <stap-probe.h>
#define PARMS 4 /* no space for saved regs */
#define JMPBUF PARMS
#define SIGMSK JMPBUF+4
+/* Don't save shadow stack register if shadow stack isn't enabled. */
+#if !defined __CET__ || (__CET__ & 2) == 0
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
+
ENTRY (_setjmp)
xorl %eax, %eax
@@ -51,6 +57,21 @@ ENTRY (_setjmp)
movl %ebp, (JB_BP*4)(%edx) /* Save caller's frame pointer. */
movl %eax, JB_SIZE(%edx) /* No signal mask set. */
+#ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+ /* Check if Shadow Stack is enabled. */
+ testl $(1 << 1), %gs:FEATURE_1_OFFSET
+ jz .Lskip_ssp
+# else
+ xorl %ecx, %ecx
+# endif
+ /* Get the current Shadow-Stack-Pointer and save it. */
+ rdsspd %ecx
+ movl %ecx, SHADOW_STACK_POINTER_OFFSET(%edx)
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+.Lskip_ssp:
+# endif
+#endif
ret
END (_setjmp)
libc_hidden_def (_setjmp)
diff --git a/sysdeps/i386/bsd-setjmp.S b/sysdeps/i386/bsd-setjmp.S
index 2da8b73c49..5f5db092e5 100644
--- a/sysdeps/i386/bsd-setjmp.S
+++ b/sysdeps/i386/bsd-setjmp.S
@@ -22,12 +22,18 @@
#include <sysdep.h>
#include <jmpbuf-offsets.h>
+#include <jmp_buf-ssp.h>
#include <stap-probe.h>
#define PARMS 4 /* no space for saved regs */
#define JMPBUF PARMS
#define SIGMSK JMPBUF+4
+/* Don't save shadow stack register if shadow stack isn't enabled. */
+#if !defined __CET__ || (__CET__ & 2) == 0
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
+
ENTRY (setjmp)
/* Note that we have to use a non-exported symbol in the next
jump since otherwise gas will emit it as a jump through the
@@ -51,6 +57,21 @@ ENTRY (setjmp)
#endif
movl %ecx, (JB_PC*4)(%eax)
movl %ebp, (JB_BP*4)(%eax) /* Save caller's frame pointer. */
+#ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+ /* Check if Shadow Stack is enabled. */
+ testl $(1 << 1), %gs:FEATURE_1_OFFSET
+ jz .Lskip_ssp
+# else
+ xorl %ecx, %ecx
+# endif
+ /* Get the current Shadow-Stack-Pointer and save it. */
+ rdsspd %ecx
+ movl %ecx, SHADOW_STACK_POINTER_OFFSET(%eax)
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+.Lskip_ssp:
+# endif
+#endif
/* Call __sigjmp_save. */
pushl $1
diff --git a/sysdeps/i386/setjmp.S b/sysdeps/i386/setjmp.S
index 6a08701717..31e26fd6d4 100644
--- a/sysdeps/i386/setjmp.S
+++ b/sysdeps/i386/setjmp.S
@@ -18,6 +18,7 @@
#include <sysdep.h>
#include <jmpbuf-offsets.h>
+#include <jmp_buf-ssp.h>
#include <asm-syntax.h>
#include <stap-probe.h>
@@ -25,6 +26,11 @@
#define JMPBUF PARMS
#define SIGMSK JMPBUF+4
+/* Don't save shadow stack register if shadow stack isn't enabled. */
+#if !defined __CET__ || (__CET__ & 2) == 0
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
+
ENTRY (__sigsetjmp)
movl JMPBUF(%esp), %eax
@@ -46,6 +52,21 @@ ENTRY (__sigsetjmp)
movl %ecx, (JB_PC*4)(%eax)
movl %ebp, (JB_BP*4)(%eax) /* Save caller's frame pointer. */
+#ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+ /* Check if Shadow Stack is enabled. */
+ testl $(1 << 1), %gs:FEATURE_1_OFFSET
+ jz .Lskip_ssp
+# else
+ xorl %ecx, %ecx
+# endif
+ /* Get the current Shadow-Stack-Pointer and save it. */
+ rdsspd %ecx
+ movl %ecx, SHADOW_STACK_POINTER_OFFSET(%eax)
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+.Lskip_ssp:
+# endif
+#endif
#if IS_IN (rtld)
/* In ld.so we never save the signal mask. */
xorl %eax, %eax
diff --git a/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S b/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
index 3452433112..7b4f4caa35 100644
--- a/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
+++ b/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
@@ -17,9 +17,14 @@
#include <sysdep.h>
#include <jmpbuf-offsets.h>
+#include <jmp_buf-ssp.h>
#include <asm-syntax.h>
#include <stap-probe.h>
+/* Don't restore shadow stack register if shadow stack isn't enabled. */
+#if !defined __CET__ || (__CET__ & 2) == 0
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
.section .rodata.str1.1,"aMS",@progbits,1
.type longjmp_msg,@object
@@ -46,6 +51,41 @@ longjmp_msg:
ENTRY (____longjmp_chk)
movl 4(%esp), %ecx /* User's jmp_buf in %ecx. */
+#ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+ /* Check if Shadow Stack is enabled. */
+ testl $(1 << 1), %gs:FEATURE_1_OFFSET
+ jz .Lnoadj
+# else
+ xorl %edx, %edx
+# endif
+ /* Check and adjust the Shadow-Stack-Pointer. */
+ rdsspd %edx
+ /* And compare it with the saved ssp value. */
+ subl SHADOW_STACK_POINTER_OFFSET(%ecx), %edx
+ je .Lnoadj
+ /* Count the number of frames to adjust and adjust it
+ with incssp instruction. The instruction can adjust
+ the ssp by [0..255] value only thus use a loop if
+ the number of frames is bigger than 255. */
+ negl %edx
+ shrl $2, %edx
+ /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
+ restoring Shadow-Stack-Pointer of setjmp's caller, we
+ need to unwind shadow stack by one more frame. */
+ addl $1, %edx
+ cmpl $255, %edx
+ jbe .Lonetime
+ movl $255, %ebx
+.Loopadj:
+ incsspd %ebx
+ subl $255, %edx
+ cmpl $255, %edx
+ ja .Loopadj
+.Lonetime:
+ incsspd %edx
+.Lnoadj:
+#endif
/* Save the return address now. */
movl (JB_PC*4)(%ecx), %edx
/* Get the stack pointer. */
diff --git a/sysdeps/unix/sysv/linux/x86/Makefile b/sysdeps/unix/sysv/linux/x86/Makefile
index c55a43e58d..111ff9ff58 100644
--- a/sysdeps/unix/sysv/linux/x86/Makefile
+++ b/sysdeps/unix/sysv/linux/x86/Makefile
@@ -21,6 +21,5 @@ sysdep_routines += dl-vdso
endif
ifeq ($(subdir),setjmp)
-gen-as-const-headers += jmp_buf-ssp.sym
tests += tst-saved_mask-1
endif
diff --git a/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S b/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
index 8a9f2e1a3c..d42289221d 100644
--- a/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
+++ b/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
@@ -20,7 +20,13 @@
#include <asm-syntax.h>
#include <stap-probe.h>
+/* Don't restore shadow stack register if shadow stack isn't enabled. */
+#if !defined __CET__ || (__CET__ & 2) == 0
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
+
#include <sigaltstack-offsets.h>
+#include <jmp_buf-ssp.h>
.section .rodata.str1.1,"aMS",@progbits,1
.type longjmp_msg,@object
@@ -105,6 +111,41 @@ ENTRY(____longjmp_chk)
cfi_restore (%rsi)
.Lok:
+#ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+ /* Check if Shadow Stack is enabled. */
+ testl $(1 << 1), %fs:FEATURE_1_OFFSET
+ jz .Lnoadj
+# else
+ xorl %eax, %eax
+# endif
+ /* Check and adjust the Shadow-Stack-Pointer. */
+ rdsspq %rax
+ /* And compare it with the saved ssp value. */
+ subq SHADOW_STACK_POINTER_OFFSET(%rdi), %rax
+ je .Lnoadj
+ /* Count the number of frames to adjust and adjust it
+ with incssp instruction. The instruction can adjust
+ the ssp by [0..255] value only thus use a loop if
+ the number of frames is bigger than 255. */
+ negq %rax
+ shrq $3, %rax
+ /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
+ restoring Shadow-Stack-Pointer of setjmp's caller, we
+ need to unwind shadow stack by one more frame. */
+ addq $1, %rax
+ cmpq $255, %rax
+ jbe .Lonetime
+ movl $255, %ebx
+.Loopadj:
+ incsspq %rbx
+ subq $255, %rax
+ cmpq $255, %rax
+ ja .Loopadj
+.Lonetime:
+ incsspq %rax
+.Lnoadj:
+#endif
LIBC_PROBE (longjmp, 3, LP_SIZE@%RDI_LP, -4@%esi, LP_SIZE@%RDX_LP)
/* We add unwind information for the target here. */
cfi_def_cfa(%rdi, 0)
diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
index d25d6f0ae4..65292f4032 100644
--- a/sysdeps/x86/Makefile
+++ b/sysdeps/x86/Makefile
@@ -10,5 +10,6 @@ tests-static += tst-get-cpu-features-static
endif
ifeq ($(subdir),setjmp)
+gen-as-const-headers += jmp_buf-ssp.sym
sysdep_routines += __longjmp_cancel
endif
diff --git a/sysdeps/x86/jmp_buf-ssp.sym b/sysdeps/x86/jmp_buf-ssp.sym
new file mode 100644
index 0000000000..1aaaedc9ec
--- /dev/null
+++ b/sysdeps/x86/jmp_buf-ssp.sym
@@ -0,0 +1 @@
+-- FIXME: Define SHADOW_STACK_POINTER_OFFSET to support shadow stack.
diff --git a/sysdeps/x86_64/__longjmp.S b/sysdeps/x86_64/__longjmp.S
index a487e0efd0..a9ebe3226e 100644
--- a/sysdeps/x86_64/__longjmp.S
+++ b/sysdeps/x86_64/__longjmp.S
@@ -17,9 +17,18 @@
#include <sysdep.h>
#include <jmpbuf-offsets.h>
+#include <jmp_buf-ssp.h>
#include <asm-syntax.h>
#include <stap-probe.h>
+/* Don't restore shadow stack register if
+ 1. Shadow stack isn't enabled. Or
+ 2. __longjmp is defined for __longjmp_cancel.
+ */
+#if !defined __CET__ || (__CET__ & 2) == 0 || defined __longjmp
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
+
/* Jump to the position specified by ENV, causing the
setjmp call there to return VAL, or 1 if VAL is 0.
void __longjmp (__jmp_buf env, int val). */
@@ -41,6 +50,42 @@ ENTRY(__longjmp)
shlq $32, %rax
orq %rax, %r9
# endif
+#endif
+#ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+ /* Check if Shadow Stack is enabled. */
+ testl $(1 << 1), %fs:FEATURE_1_OFFSET
+ jz .Lnoadj
+# else
+ xorl %eax, %eax
+# endif
+ /* Check and adjust the Shadow-Stack-Pointer. */
+ /* Get the current ssp. */
+ rdsspq %rax
+ /* And compare it with the saved ssp value. */
+ subq SHADOW_STACK_POINTER_OFFSET(%rdi), %rax
+ je .Lnoadj
+ /* Count the number of frames to adjust and adjust it
+ with incssp instruction. The instruction can adjust
+ the ssp by [0..255] value only thus use a loop if
+ the number of frames is bigger than 255. */
+ negq %rax
+ shrq $3, %rax
+ /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
+ restoring Shadow-Stack-Pointer of setjmp's caller, we
+ need to unwind shadow stack by one more frame. */
+ addq $1, %rax
+ cmpq $255, %rax
+ jbe .Lonetime
+ movl $255, %ebx
+.Loopadj:
+ incsspq %rbx
+ subq $255, %rax
+ cmpq $255, %rax
+ ja .Loopadj
+.Lonetime:
+ incsspq %rax
+.Lnoadj:
#endif
LIBC_PROBE (longjmp, 3, LP_SIZE@%RDI_LP, -4@%esi, LP_SIZE@%RDX_LP)
/* We add unwind information for the target here. */
diff --git a/sysdeps/x86_64/setjmp.S b/sysdeps/x86_64/setjmp.S
index e0a648e3e4..bd9bb0ee6b 100644
--- a/sysdeps/x86_64/setjmp.S
+++ b/sysdeps/x86_64/setjmp.S
@@ -18,9 +18,15 @@
#include <sysdep.h>
#include <jmpbuf-offsets.h>
+#include <jmp_buf-ssp.h>
#include <asm-syntax.h>
#include <stap-probe.h>
+/* Don't save shadow stack register if shadow stack isn't enabled. */
+#if !defined __CET__ || (__CET__ & 2) == 0
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
+
ENTRY (__sigsetjmp)
/* Save registers. */
movq %rbx, (JB_RBX*8)(%rdi)
@@ -54,6 +60,21 @@ ENTRY (__sigsetjmp)
#endif
movq %rax, (JB_PC*8)(%rdi)
+#ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+ /* Check if Shadow Stack is enabled. */
+ testl $(1 << 1), %fs:FEATURE_1_OFFSET
+ jz .Lskip_ssp
+# else
+ xorl %eax, %eax
+# endif
+ /* Get the current Shadow-Stack-Pointer and save it. */
+ rdsspq %rax
+ movq %rax, SHADOW_STACK_POINTER_OFFSET(%rdi)
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+.Lskip_ssp:
+# endif
+#endif
#if IS_IN (rtld)
/* In ld.so we never save the signal mask. */
xorl %eax, %eax
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* Re: [PATCH 02/24] x86: Support shadow stack pointer in setjmp/longjmp
2018-06-13 15:32 ` [PATCH 02/24] x86: Support shadow stack pointer in setjmp/longjmp H.J. Lu
@ 2018-07-12 18:13 ` Carlos O'Donell
2018-07-13 13:23 ` V2: " H.J. Lu
0 siblings, 1 reply; 54+ messages in thread
From: Carlos O'Donell @ 2018-07-12 18:13 UTC (permalink / raw)
To: H.J. Lu, libc-alpha
On 06/13/2018 11:31 AM, H.J. Lu wrote:
> Save and restore shadow stack pointer in setjmp and longjmp to support
> shadow stack in Intel CET. Use feature_1 in tcbhead_t to check if
> shadow stack is enabled before saving and restoring shadow stack
> pointer so that it works with the old smaller cancel_jmp_buf which
> doesn't have space for shadow stack pointer.
This comment can't be accurate. For the older smaller cancel_jmp_buf
we found another way to solve this because you just don't restore the
shadowstack since we're jumping out through the unwinder. So we only
need this logically for setjmp/longjmp and *context functions?
In general this is OK, I'd like to see a v2:
- New accurate commit message.
- Replace (1 << 1) with meaningful macro constants that help a future
reader identify which FEATURE_1 flag we're looking at.
>
> 2017-12-07 Igor Tsimbalist <igor.v.tsimbalist@intel.com>
> H.J. Lu <hongjiu.lu@intel.com>
>
> * sysdeps/i386/__longjmp.S: Include <jmp_buf-ssp.h>.
> (__longjmp): Restore shadow stack pointer if shadow stack is
> enabled, SHADOW_STACK_POINTER_OFFSET is defined and __longjmp
> isn't defined for __longjmp_cancel.
> * sysdeps/i386/bsd-_setjmp.S: Include <jmp_buf-ssp.h>.
> (_setjmp): Save shadow stack pointer if shadow stack is enabled
> and SHADOW_STACK_POINTER_OFFSET is defined.
> * sysdeps/i386/bsd-setjmp.S: Include <jmp_buf-ssp.h>.
> (setjmp): Save shadow stack pointer if shadow stack is enabled
> and SHADOW_STACK_POINTER_OFFSET is defined.
> * sysdeps/i386/setjmp.S: Include <jmp_buf-ssp.h>.
> (__sigsetjmp): Save shadow stack pointer if shadow stack is
> enabled and SHADOW_STACK_POINTER_OFFSET is defined.
> * sysdeps/unix/sysv/linux/i386/____longjmp_chk.S: Include
> <jmp_buf-ssp.h>.
> (____longjmp_chk): Restore shadow stack pointer if shadow stack
> is enabled and SHADOW_STACK_POINTER_OFFSET is defined.
> * sysdeps/unix/sysv/linux/x86/Makefile (gen-as-const-headers):
> Remove jmp_buf-ssp.sym.
> * sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S: Include
> <jmp_buf-ssp.h>.
> (____longjmp_chk): Restore shadow stack pointer if shadow stack
> is enabled and SHADOW_STACK_POINTER_OFFSET is defined.
> * sysdeps/x86/Makefile (gen-as-const-headers): Add
> jmp_buf-ssp.sym.
> * sysdeps/x86/jmp_buf-ssp.sym: New dummy file.
> * sysdeps/x86_64/__longjmp.S: Include <jmp_buf-ssp.h>.
> (__longjmp): Restore shadow stack pointer if shadow stack is
> enabled, SHADOW_STACK_POINTER_OFFSET is defined and __longjmp
> isn't defined for __longjmp_cancel.
> * sysdeps/x86_64/setjmp.S: Include <jmp_buf-ssp.h>.
> (__sigsetjmp): Save shadow stack pointer if shadow stack is
> enabled and SHADOW_STACK_POINTER_OFFSET is defined.
> ---
> sysdeps/i386/__longjmp.S | 78 +++++++++++++++++++
> sysdeps/i386/bsd-_setjmp.S | 21 +++++
> sysdeps/i386/bsd-setjmp.S | 21 +++++
> sysdeps/i386/setjmp.S | 21 +++++
> .../unix/sysv/linux/i386/____longjmp_chk.S | 40 ++++++++++
> sysdeps/unix/sysv/linux/x86/Makefile | 1 -
> .../unix/sysv/linux/x86_64/____longjmp_chk.S | 41 ++++++++++
> sysdeps/x86/Makefile | 1 +
> sysdeps/x86/jmp_buf-ssp.sym | 1 +
> sysdeps/x86_64/__longjmp.S | 45 +++++++++++
> sysdeps/x86_64/setjmp.S | 21 +++++
> 11 files changed, 290 insertions(+), 1 deletion(-)
> create mode 100644 sysdeps/x86/jmp_buf-ssp.sym
>
> diff --git a/sysdeps/i386/__longjmp.S b/sysdeps/i386/__longjmp.S
> index b38333bead..8b5d7f3d44 100644
> --- a/sysdeps/i386/__longjmp.S
> +++ b/sysdeps/i386/__longjmp.S
> @@ -18,14 +18,57 @@
>
> #include <sysdep.h>
> #include <jmpbuf-offsets.h>
> +#include <jmp_buf-ssp.h>
OK.
> #include <asm-syntax.h>
> #include <stap-probe.h>
>
> +/* Don't restore shadow stack register if
> + 1. Shadow stack isn't enabled. Or
> + 2. __longjmp is defined for __longjmp_cancel.
> + */
> +#if !defined __CET__ || (__CET__ & 2) == 0 || defined __longjmp
> +# undef SHADOW_STACK_POINTER_OFFSET
> +#endif
> +
OK.
> .text
> ENTRY (__longjmp)
> #ifdef PTR_DEMANGLE
> movl 4(%esp), %eax /* User's jmp_buf in %eax. */
>
> +# ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> + /* Check if Shadow Stack is enabled. */
> + testl $(1 << 1), %gs:FEATURE_1_OFFSET
Please replace all instances of "1" here with some kind of macro
that actually defines which flag we're checking.
> + jz .Lnoadj
> +# else
> + xorl %edx, %edx
> +# endif
> + /* Check and adjust the Shadow-Stack-Pointer. */
> + rdsspd %edx
> + /* And compare it with the saved ssp value. */
> + subl SHADOW_STACK_POINTER_OFFSET(%eax), %edx
> + je .Lnoadj
> + /* Count the number of frames to adjust and adjust it
> + with incssp instruction. The instruction can adjust
> + the ssp by [0..255] value only thus use a loop if
> + the number of frames is bigger than 255. */
> + negl %edx
> + shrl $2, %edx
> + /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
> + restoring Shadow-Stack-Pointer of setjmp's caller, we
> + need to unwind shadow stack by one more frame. */
> + addl $1, %edx
> + cmpl $255, %edx
> + jbe .Lonetime
> +.Loopadj:
> + incsspd %edx
> + subl $255, %edx
> + cmpl $255, %edx
> + ja .Loopadj
> +.Lonetime:
> + incsspd %edx
> +.Lnoadj:
> +# endif
OK.
> /* Save the return address now. */
> movl (JB_PC*4)(%eax), %edx
> /* Get the stack pointer. */
> @@ -56,6 +99,41 @@ ENTRY (__longjmp)
> #else
> movl 4(%esp), %ecx /* User's jmp_buf in %ecx. */
> movl 8(%esp), %eax /* Second argument is return value. */
> +# ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED
> + /* Check if Shadow Stack is enabled. */
> + testl $(1 << 1), %gs:FEATURE_1_OFFSET
> + jz .Lnoadj
> +# endif
> + /* Check and adjust the Shadow-Stack-Pointer. */
> + xorl %edx, %edx
> + /* Get the current ssp. */
> + rdsspd %edx
> + /* And compare it with the saved ssp value. */
> + subl SHADOW_STACK_POINTER_OFFSET(%ecx), %edx
> + je .Lnoadj
> + /* Count the number of frames to adjust and adjust it
> + with incssp instruction. The instruction can adjust
> + the ssp by [0..255] value only thus use a loop if
> + the number of frames is bigger than 255. */
> + negl %edx
> + shrl $2, %edx
> + /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
> + restoring Shadow-Stack-Pointer of setjmp's caller, we
> + need to unwind shadow stack by one more frame. */
OK.
> + addl $1, %edx
> + cmpl $255, %edx
> + jbe .Lonetime
> + movl $255, %ebx
> +.Loopadj:
> + incsspd %ebx
> + subl $255, %edx
> + cmpl $255, %edx
> + ja .Loopadj
> +.Lonetime:
> + incsspd %edx
> +.Lnoadj:
OK.
> +# endif
> /* Save the return address now. */
> movl (JB_PC*4)(%ecx), %edx
> LIBC_PROBE (longjmp, 3, 4@%ecx, -4@%eax, 4@%edx)
> diff --git a/sysdeps/i386/bsd-_setjmp.S b/sysdeps/i386/bsd-_setjmp.S
> index a626cc6d22..5b09e5dbf8 100644
> --- a/sysdeps/i386/bsd-_setjmp.S
> +++ b/sysdeps/i386/bsd-_setjmp.S
> @@ -22,12 +22,18 @@
>
> #include <sysdep.h>
> #include <jmpbuf-offsets.h>
> +#include <jmp_buf-ssp.h>
OK.
> #include <stap-probe.h>
>
> #define PARMS 4 /* no space for saved regs */
> #define JMPBUF PARMS
> #define SIGMSK JMPBUF+4
>
> +/* Don't save shadow stack register if shadow stack isn't enabled. */
> +#if !defined __CET__ || (__CET__ & 2) == 0
> +# undef SHADOW_STACK_POINTER_OFFSET
> +#endif
OK.
> +
> ENTRY (_setjmp)
>
> xorl %eax, %eax
> @@ -51,6 +57,21 @@ ENTRY (_setjmp)
> movl %ebp, (JB_BP*4)(%edx) /* Save caller's frame pointer. */
>
> movl %eax, JB_SIZE(%edx) /* No signal mask set. */
> +#ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> + /* Check if Shadow Stack is enabled. */
> + testl $(1 << 1), %gs:FEATURE_1_OFFSET
> + jz .Lskip_ssp
> +# else
> + xorl %ecx, %ecx
> +# endif
> + /* Get the current Shadow-Stack-Pointer and save it. */
> + rdsspd %ecx
> + movl %ecx, SHADOW_STACK_POINTER_OFFSET(%edx)
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> +.Lskip_ssp:
> +# endif
> +#endif
OK.
> ret
> END (_setjmp)
> libc_hidden_def (_setjmp)
> diff --git a/sysdeps/i386/bsd-setjmp.S b/sysdeps/i386/bsd-setjmp.S
> index 2da8b73c49..5f5db092e5 100644
> --- a/sysdeps/i386/bsd-setjmp.S
> +++ b/sysdeps/i386/bsd-setjmp.S
> @@ -22,12 +22,18 @@
>
> #include <sysdep.h>
> #include <jmpbuf-offsets.h>
> +#include <jmp_buf-ssp.h>
OK.
> #include <stap-probe.h>
>
> #define PARMS 4 /* no space for saved regs */
> #define JMPBUF PARMS
> #define SIGMSK JMPBUF+4
>
> +/* Don't save shadow stack register if shadow stack isn't enabled. */
> +#if !defined __CET__ || (__CET__ & 2) == 0
> +# undef SHADOW_STACK_POINTER_OFFSET
> +#endif
> +
OK.
> ENTRY (setjmp)
> /* Note that we have to use a non-exported symbol in the next
> jump since otherwise gas will emit it as a jump through the
> @@ -51,6 +57,21 @@ ENTRY (setjmp)
> #endif
> movl %ecx, (JB_PC*4)(%eax)
> movl %ebp, (JB_BP*4)(%eax) /* Save caller's frame pointer. */
> +#ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> + /* Check if Shadow Stack is enabled. */
> + testl $(1 << 1), %gs:FEATURE_1_OFFSET
> + jz .Lskip_ssp
> +# else
> + xorl %ecx, %ecx
> +# endif
> + /* Get the current Shadow-Stack-Pointer and save it. */
> + rdsspd %ecx
> + movl %ecx, SHADOW_STACK_POINTER_OFFSET(%eax)
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> +.Lskip_ssp:
> +# endif
> +#endif
OK.
>
> /* Call __sigjmp_save. */
> pushl $1
> diff --git a/sysdeps/i386/setjmp.S b/sysdeps/i386/setjmp.S
> index 6a08701717..31e26fd6d4 100644
> --- a/sysdeps/i386/setjmp.S
> +++ b/sysdeps/i386/setjmp.S
> @@ -18,6 +18,7 @@
>
> #include <sysdep.h>
> #include <jmpbuf-offsets.h>
> +#include <jmp_buf-ssp.h>
OK.
> #include <asm-syntax.h>
> #include <stap-probe.h>
>
> @@ -25,6 +26,11 @@
> #define JMPBUF PARMS
> #define SIGMSK JMPBUF+4
>
> +/* Don't save shadow stack register if shadow stack isn't enabled. */
> +#if !defined __CET__ || (__CET__ & 2) == 0
> +# undef SHADOW_STACK_POINTER_OFFSET
> +#endif
> +
OK.
> ENTRY (__sigsetjmp)
>
> movl JMPBUF(%esp), %eax
> @@ -46,6 +52,21 @@ ENTRY (__sigsetjmp)
> movl %ecx, (JB_PC*4)(%eax)
> movl %ebp, (JB_BP*4)(%eax) /* Save caller's frame pointer. */
>
> +#ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> + /* Check if Shadow Stack is enabled. */
> + testl $(1 << 1), %gs:FEATURE_1_OFFSET
> + jz .Lskip_ssp
> +# else
> + xorl %ecx, %ecx
> +# endif
> + /* Get the current Shadow-Stack-Pointer and save it. */
> + rdsspd %ecx
> + movl %ecx, SHADOW_STACK_POINTER_OFFSET(%eax)
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> +.Lskip_ssp:
> +# endif
> +#endif
OK.
> #if IS_IN (rtld)
> /* In ld.so we never save the signal mask. */
> xorl %eax, %eax
> diff --git a/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S b/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
> index 3452433112..7b4f4caa35 100644
> --- a/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
> +++ b/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
> @@ -17,9 +17,14 @@
>
> #include <sysdep.h>
> #include <jmpbuf-offsets.h>
> +#include <jmp_buf-ssp.h>
OK.
> #include <asm-syntax.h>
> #include <stap-probe.h>
>
> +/* Don't restore shadow stack register if shadow stack isn't enabled. */
> +#if !defined __CET__ || (__CET__ & 2) == 0
> +# undef SHADOW_STACK_POINTER_OFFSET
> +#endif
OK.
>
> .section .rodata.str1.1,"aMS",@progbits,1
> .type longjmp_msg,@object
> @@ -46,6 +51,41 @@ longjmp_msg:
> ENTRY (____longjmp_chk)
> movl 4(%esp), %ecx /* User's jmp_buf in %ecx. */
>
> +#ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> + /* Check if Shadow Stack is enabled. */
> + testl $(1 << 1), %gs:FEATURE_1_OFFSET
> + jz .Lnoadj
> +# else
> + xorl %edx, %edx
> +# endif
> + /* Check and adjust the Shadow-Stack-Pointer. */
> + rdsspd %edx
> + /* And compare it with the saved ssp value. */
> + subl SHADOW_STACK_POINTER_OFFSET(%ecx), %edx
> + je .Lnoadj
> + /* Count the number of frames to adjust and adjust it
> + with incssp instruction. The instruction can adjust
> + the ssp by [0..255] value only thus use a loop if
> + the number of frames is bigger than 255. */
> + negl %edx
> + shrl $2, %edx
> + /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
> + restoring Shadow-Stack-Pointer of setjmp's caller, we
> + need to unwind shadow stack by one more frame. */
> + addl $1, %edx
> + cmpl $255, %edx
> + jbe .Lonetime
> + movl $255, %ebx
> +.Loopadj:
> + incsspd %ebx
> + subl $255, %edx
> + cmpl $255, %edx
> + ja .Loopadj
> +.Lonetime:
> + incsspd %edx
> +.Lnoadj:
> +#endif
OK.
> /* Save the return address now. */
> movl (JB_PC*4)(%ecx), %edx
> /* Get the stack pointer. */
> diff --git a/sysdeps/unix/sysv/linux/x86/Makefile b/sysdeps/unix/sysv/linux/x86/Makefile
> index c55a43e58d..111ff9ff58 100644
> --- a/sysdeps/unix/sysv/linux/x86/Makefile
> +++ b/sysdeps/unix/sysv/linux/x86/Makefile
> @@ -21,6 +21,5 @@ sysdep_routines += dl-vdso
> endif
>
> ifeq ($(subdir),setjmp)
> -gen-as-const-headers += jmp_buf-ssp.sym
OK.
> tests += tst-saved_mask-1
> endif
> diff --git a/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S b/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
> index 8a9f2e1a3c..d42289221d 100644
> --- a/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
> +++ b/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
> @@ -20,7 +20,13 @@
> #include <asm-syntax.h>
> #include <stap-probe.h>
>
> +/* Don't restore shadow stack register if shadow stack isn't enabled. */
> +#if !defined __CET__ || (__CET__ & 2) == 0
> +# undef SHADOW_STACK_POINTER_OFFSET
> +#endif
> +
OK.
> #include <sigaltstack-offsets.h>
> +#include <jmp_buf-ssp.h>
OK.
>
> .section .rodata.str1.1,"aMS",@progbits,1
> .type longjmp_msg,@object
> @@ -105,6 +111,41 @@ ENTRY(____longjmp_chk)
> cfi_restore (%rsi)
>
> .Lok:
> +#ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> + /* Check if Shadow Stack is enabled. */
> + testl $(1 << 1), %fs:FEATURE_1_OFFSET
> + jz .Lnoadj
> +# else
> + xorl %eax, %eax
> +# endif
> + /* Check and adjust the Shadow-Stack-Pointer. */
> + rdsspq %rax
> + /* And compare it with the saved ssp value. */
> + subq SHADOW_STACK_POINTER_OFFSET(%rdi), %rax
> + je .Lnoadj
> + /* Count the number of frames to adjust and adjust it
> + with incssp instruction. The instruction can adjust
> + the ssp by [0..255] value only thus use a loop if
> + the number of frames is bigger than 255. */
> + negq %rax
> + shrq $3, %rax
> + /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
> + restoring Shadow-Stack-Pointer of setjmp's caller, we
> + need to unwind shadow stack by one more frame. */
> + addq $1, %rax
> + cmpq $255, %rax
> + jbe .Lonetime
> + movl $255, %ebx
> +.Loopadj:
> + incsspq %rbx
> + subq $255, %rax
> + cmpq $255, %rax
> + ja .Loopadj
> +.Lonetime:
> + incsspq %rax
> +.Lnoadj:
> +#endif
OK.
> LIBC_PROBE (longjmp, 3, LP_SIZE@%RDI_LP, -4@%esi, LP_SIZE@%RDX_LP)
> /* We add unwind information for the target here. */
> cfi_def_cfa(%rdi, 0)
> diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
> index d25d6f0ae4..65292f4032 100644
> --- a/sysdeps/x86/Makefile
> +++ b/sysdeps/x86/Makefile
> @@ -10,5 +10,6 @@ tests-static += tst-get-cpu-features-static
> endif
>
> ifeq ($(subdir),setjmp)
> +gen-as-const-headers += jmp_buf-ssp.sym
OK.
> sysdep_routines += __longjmp_cancel
> endif
> diff --git a/sysdeps/x86/jmp_buf-ssp.sym b/sysdeps/x86/jmp_buf-ssp.sym
> new file mode 100644
> index 0000000000..1aaaedc9ec
> --- /dev/null
> +++ b/sysdeps/x86/jmp_buf-ssp.sym
> @@ -0,0 +1 @@
> +-- FIXME: Define SHADOW_STACK_POINTER_OFFSET to support shadow stack.
> diff --git a/sysdeps/x86_64/__longjmp.S b/sysdeps/x86_64/__longjmp.S
> index a487e0efd0..a9ebe3226e 100644
> --- a/sysdeps/x86_64/__longjmp.S
> +++ b/sysdeps/x86_64/__longjmp.S
> @@ -17,9 +17,18 @@
>
> #include <sysdep.h>
> #include <jmpbuf-offsets.h>
> +#include <jmp_buf-ssp.h>
OK.
> #include <asm-syntax.h>
> #include <stap-probe.h>
>
> +/* Don't restore shadow stack register if
> + 1. Shadow stack isn't enabled. Or
> + 2. __longjmp is defined for __longjmp_cancel.
> + */
> +#if !defined __CET__ || (__CET__ & 2) == 0 || defined __longjmp
> +# undef SHADOW_STACK_POINTER_OFFSET
> +#endif
> +
OK.
> /* Jump to the position specified by ENV, causing the
> setjmp call there to return VAL, or 1 if VAL is 0.
> void __longjmp (__jmp_buf env, int val). */
> @@ -41,6 +50,42 @@ ENTRY(__longjmp)
> shlq $32, %rax
> orq %rax, %r9
> # endif
> +#endif
> +#ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> + /* Check if Shadow Stack is enabled. */
> + testl $(1 << 1), %fs:FEATURE_1_OFFSET
> + jz .Lnoadj
> +# else
> + xorl %eax, %eax
> +# endif
> + /* Check and adjust the Shadow-Stack-Pointer. */
> + /* Get the current ssp. */
> + rdsspq %rax
> + /* And compare it with the saved ssp value. */
> + subq SHADOW_STACK_POINTER_OFFSET(%rdi), %rax
> + je .Lnoadj
> + /* Count the number of frames to adjust and adjust it
> + with incssp instruction. The instruction can adjust
> + the ssp by [0..255] value only thus use a loop if
> + the number of frames is bigger than 255. */
> + negq %rax
> + shrq $3, %rax
> + /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
> + restoring Shadow-Stack-Pointer of setjmp's caller, we
> + need to unwind shadow stack by one more frame. */
> + addq $1, %rax
> + cmpq $255, %rax
> + jbe .Lonetime
> + movl $255, %ebx
> +.Loopadj:
> + incsspq %rbx
> + subq $255, %rax
> + cmpq $255, %rax
> + ja .Loopadj
> +.Lonetime:
> + incsspq %rax
> +.Lnoadj:
OK.
> #endif
> LIBC_PROBE (longjmp, 3, LP_SIZE@%RDI_LP, -4@%esi, LP_SIZE@%RDX_LP)
> /* We add unwind information for the target here. */
> diff --git a/sysdeps/x86_64/setjmp.S b/sysdeps/x86_64/setjmp.S
> index e0a648e3e4..bd9bb0ee6b 100644
> --- a/sysdeps/x86_64/setjmp.S
> +++ b/sysdeps/x86_64/setjmp.S
> @@ -18,9 +18,15 @@
>
> #include <sysdep.h>
> #include <jmpbuf-offsets.h>
> +#include <jmp_buf-ssp.h>
OK.
> #include <asm-syntax.h>
> #include <stap-probe.h>
>
> +/* Don't save shadow stack register if shadow stack isn't enabled. */
> +#if !defined __CET__ || (__CET__ & 2) == 0
> +# undef SHADOW_STACK_POINTER_OFFSET
> +#endif
> +
OK.
> ENTRY (__sigsetjmp)
> /* Save registers. */
> movq %rbx, (JB_RBX*8)(%rdi)
> @@ -54,6 +60,21 @@ ENTRY (__sigsetjmp)
> #endif
> movq %rax, (JB_PC*8)(%rdi)
>
> +#ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> + /* Check if Shadow Stack is enabled. */
> + testl $(1 << 1), %fs:FEATURE_1_OFFSET
> + jz .Lskip_ssp
> +# else
> + xorl %eax, %eax
> +# endif
> + /* Get the current Shadow-Stack-Pointer and save it. */
> + rdsspq %rax
> + movq %rax, SHADOW_STACK_POINTER_OFFSET(%rdi)
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> +.Lskip_ssp:
> +# endif
> +#endif
OK.
> #if IS_IN (rtld)
> /* In ld.so we never save the signal mask. */
> xorl %eax, %eax
>
--
Cheers,
Carlos.
^ permalink raw reply [flat|nested] 54+ messages in thread
* V2: [PATCH 02/24] x86: Support shadow stack pointer in setjmp/longjmp
2018-07-12 18:13 ` Carlos O'Donell
@ 2018-07-13 13:23 ` H.J. Lu
2018-07-13 18:49 ` Carlos O'Donell
2018-07-14 19:57 ` Florian Weimer
0 siblings, 2 replies; 54+ messages in thread
From: H.J. Lu @ 2018-07-13 13:23 UTC (permalink / raw)
To: Carlos O'Donell; +Cc: libc-alpha
On Thu, Jul 12, 2018 at 02:13:21PM -0400, Carlos O'Donell wrote:
> On 06/13/2018 11:31 AM, H.J. Lu wrote:
> > Save and restore shadow stack pointer in setjmp and longjmp to support
> > shadow stack in Intel CET. Use feature_1 in tcbhead_t to check if
> > shadow stack is enabled before saving and restoring shadow stack
> > pointer so that it works with the old smaller cancel_jmp_buf which
> > doesn't have space for shadow stack pointer.
>
> This comment can't be accurate. For the older smaller cancel_jmp_buf
> we found another way to solve this because you just don't restore the
> shadowstack since we're jumping out through the unwinder. So we only
> need this logically for setjmp/longjmp and *context functions?
>
> In general this is OK, I'd like to see a v2:
>
> - New accurate commit message.
> - Replace (1 << 1) with meaningful macro constants that help a future
> reader identify which FEATURE_1 flag we're looking at.
>
Done.
...
> >
> > +# ifdef SHADOW_STACK_POINTER_OFFSET
> > +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> > + /* Check if Shadow Stack is enabled. */
> > + testl $(1 << 1), %gs:FEATURE_1_OFFSET
>
> Please replace all instances of "1" here with some kind of macro
> that actually defines which flag we're checking.
>
I updated [PATCH 01/24] to add X86_FEATURE_1_IBT and X86_FEATURE_1_SHSTK
in
https://sourceware.org/ml/libc-alpha/2018-07/msg00375.html
Here is the V2 patch. OK for master?
Thanks.
H.J.
----
Save and restore shadow stack pointer in setjmp and longjmp to support
shadow stack in Intel CET. Use feature_1 in tcbhead_t to check if
shadow stack is enabled before saving and restoring shadow stack pointer.
2017-12-07 Igor Tsimbalist <igor.v.tsimbalist@intel.com>
H.J. Lu <hongjiu.lu@intel.com>
* sysdeps/i386/__longjmp.S: Include <jmp_buf-ssp.h>.
(__longjmp): Restore shadow stack pointer if shadow stack is
enabled, SHADOW_STACK_POINTER_OFFSET is defined and __longjmp
isn't defined for __longjmp_cancel.
* sysdeps/i386/bsd-_setjmp.S: Include <jmp_buf-ssp.h>.
(_setjmp): Save shadow stack pointer if shadow stack is enabled
and SHADOW_STACK_POINTER_OFFSET is defined.
* sysdeps/i386/bsd-setjmp.S: Include <jmp_buf-ssp.h>.
(setjmp): Save shadow stack pointer if shadow stack is enabled
and SHADOW_STACK_POINTER_OFFSET is defined.
* sysdeps/i386/setjmp.S: Include <jmp_buf-ssp.h>.
(__sigsetjmp): Save shadow stack pointer if shadow stack is
enabled and SHADOW_STACK_POINTER_OFFSET is defined.
* sysdeps/unix/sysv/linux/i386/____longjmp_chk.S: Include
<jmp_buf-ssp.h>.
(____longjmp_chk): Restore shadow stack pointer if shadow stack
is enabled and SHADOW_STACK_POINTER_OFFSET is defined.
* sysdeps/unix/sysv/linux/x86/Makefile (gen-as-const-headers):
Remove jmp_buf-ssp.sym.
* sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S: Include
<jmp_buf-ssp.h>.
(____longjmp_chk): Restore shadow stack pointer if shadow stack
is enabled and SHADOW_STACK_POINTER_OFFSET is defined.
* sysdeps/x86/Makefile (gen-as-const-headers): Add
jmp_buf-ssp.sym.
* sysdeps/x86/jmp_buf-ssp.sym: New dummy file.
* sysdeps/x86_64/__longjmp.S: Include <jmp_buf-ssp.h>.
(__longjmp): Restore shadow stack pointer if shadow stack is
enabled, SHADOW_STACK_POINTER_OFFSET is defined and __longjmp
isn't defined for __longjmp_cancel.
* sysdeps/x86_64/setjmp.S: Include <jmp_buf-ssp.h>.
(__sigsetjmp): Save shadow stack pointer if shadow stack is
enabled and SHADOW_STACK_POINTER_OFFSET is defined.
---
sysdeps/i386/__longjmp.S | 73 +++++++++++++++++++
sysdeps/i386/bsd-_setjmp.S | 21 ++++++
sysdeps/i386/bsd-setjmp.S | 21 ++++++
sysdeps/i386/setjmp.S | 21 ++++++
.../unix/sysv/linux/i386/____longjmp_chk.S | 37 ++++++++++
sysdeps/unix/sysv/linux/x86/Makefile | 1 -
.../unix/sysv/linux/x86_64/____longjmp_chk.S | 38 ++++++++++
sysdeps/x86/Makefile | 1 +
sysdeps/x86/jmp_buf-ssp.sym | 1 +
sysdeps/x86_64/__longjmp.S | 44 +++++++++++
sysdeps/x86_64/setjmp.S | 21 ++++++
11 files changed, 278 insertions(+), 1 deletion(-)
create mode 100644 sysdeps/x86/jmp_buf-ssp.sym
diff --git a/sysdeps/i386/__longjmp.S b/sysdeps/i386/__longjmp.S
index b38333bead..6e98ed538d 100644
--- a/sysdeps/i386/__longjmp.S
+++ b/sysdeps/i386/__longjmp.S
@@ -18,14 +18,55 @@
#include <sysdep.h>
#include <jmpbuf-offsets.h>
+#include <jmp_buf-ssp.h>
#include <asm-syntax.h>
#include <stap-probe.h>
+/* Don't restore shadow stack register if
+ 1. Shadow stack isn't enabled. Or
+ 2. __longjmp is defined for __longjmp_cancel.
+ */
+#if !SHSTK_ENABLED || defined __longjmp
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
+
.text
ENTRY (__longjmp)
#ifdef PTR_DEMANGLE
movl 4(%esp), %eax /* User's jmp_buf in %eax. */
+# ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+ /* Check if Shadow Stack is enabled. */
+ testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
+ jz L(skip_ssp)
+# else
+ xorl %edx, %edx
+# endif
+ /* Check and adjust the Shadow-Stack-Pointer. */
+ rdsspd %edx
+ /* And compare it with the saved ssp value. */
+ subl SHADOW_STACK_POINTER_OFFSET(%eax), %edx
+ je L(skip_ssp)
+ /* Count the number of frames to adjust and adjust it
+ with incssp instruction. The instruction can adjust
+ the ssp by [0..255] value only thus use a loop if
+ the number of frames is bigger than 255. */
+ negl %edx
+ shrl $2, %edx
+ /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
+ restoring Shadow-Stack-Pointer of setjmp's caller, we
+ need to unwind shadow stack by one more frame. */
+ addl $1, %edx
+ movl $255, %ebx
+L(loop):
+ cmpl %ebx, %edx
+ cmovb %edx, %ebx
+ incsspd %ebx
+ subl %ebx, %edx
+ ja L(loop)
+L(skip_ssp):
+# endif
/* Save the return address now. */
movl (JB_PC*4)(%eax), %edx
/* Get the stack pointer. */
@@ -56,6 +97,38 @@ ENTRY (__longjmp)
#else
movl 4(%esp), %ecx /* User's jmp_buf in %ecx. */
movl 8(%esp), %eax /* Second argument is return value. */
+# ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED
+ /* Check if Shadow Stack is enabled. */
+ testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
+ jz L(skip_ssp)
+# endif
+ /* Check and adjust the Shadow-Stack-Pointer. */
+ xorl %edx, %edx
+ /* Get the current ssp. */
+ rdsspd %edx
+ /* And compare it with the saved ssp value. */
+ subl SHADOW_STACK_POINTER_OFFSET(%ecx), %edx
+ je L(skip_ssp)
+ /* Count the number of frames to adjust and adjust it
+ with incssp instruction. The instruction can adjust
+ the ssp by [0..255] value only thus use a loop if
+ the number of frames is bigger than 255. */
+ negl %edx
+ shrl $2, %edx
+ /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
+ restoring Shadow-Stack-Pointer of setjmp's caller, we
+ need to unwind shadow stack by one more frame. */
+ addl $1, %edx
+ movl $255, %ebx
+L(loop):
+ cmpl %ebx, %edx
+ cmovb %edx, %ebx
+ incsspd %ebx
+ subl %ebx, %edx
+ ja L(loop)
+L(skip_ssp):
+# endif
/* Save the return address now. */
movl (JB_PC*4)(%ecx), %edx
LIBC_PROBE (longjmp, 3, 4@%ecx, -4@%eax, 4@%edx)
diff --git a/sysdeps/i386/bsd-_setjmp.S b/sysdeps/i386/bsd-_setjmp.S
index a626cc6d22..db47df0ba1 100644
--- a/sysdeps/i386/bsd-_setjmp.S
+++ b/sysdeps/i386/bsd-_setjmp.S
@@ -22,12 +22,18 @@
#include <sysdep.h>
#include <jmpbuf-offsets.h>
+#include <jmp_buf-ssp.h>
#include <stap-probe.h>
#define PARMS 4 /* no space for saved regs */
#define JMPBUF PARMS
#define SIGMSK JMPBUF+4
+/* Don't save shadow stack register if shadow stack isn't enabled. */
+#if !SHSTK_ENABLED
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
+
ENTRY (_setjmp)
xorl %eax, %eax
@@ -51,6 +57,21 @@ ENTRY (_setjmp)
movl %ebp, (JB_BP*4)(%edx) /* Save caller's frame pointer. */
movl %eax, JB_SIZE(%edx) /* No signal mask set. */
+#ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+ /* Check if Shadow Stack is enabled. */
+ testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
+ jz L(skip_ssp)
+# else
+ xorl %ecx, %ecx
+# endif
+ /* Get the current Shadow-Stack-Pointer and save it. */
+ rdsspd %ecx
+ movl %ecx, SHADOW_STACK_POINTER_OFFSET(%edx)
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+L(skip_ssp):
+# endif
+#endif
ret
END (_setjmp)
libc_hidden_def (_setjmp)
diff --git a/sysdeps/i386/bsd-setjmp.S b/sysdeps/i386/bsd-setjmp.S
index 2da8b73c49..1290d0d82b 100644
--- a/sysdeps/i386/bsd-setjmp.S
+++ b/sysdeps/i386/bsd-setjmp.S
@@ -22,12 +22,18 @@
#include <sysdep.h>
#include <jmpbuf-offsets.h>
+#include <jmp_buf-ssp.h>
#include <stap-probe.h>
#define PARMS 4 /* no space for saved regs */
#define JMPBUF PARMS
#define SIGMSK JMPBUF+4
+/* Don't save shadow stack register if shadow stack isn't enabled. */
+#if !SHSTK_ENABLED
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
+
ENTRY (setjmp)
/* Note that we have to use a non-exported symbol in the next
jump since otherwise gas will emit it as a jump through the
@@ -51,6 +57,21 @@ ENTRY (setjmp)
#endif
movl %ecx, (JB_PC*4)(%eax)
movl %ebp, (JB_BP*4)(%eax) /* Save caller's frame pointer. */
+#ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+ /* Check if Shadow Stack is enabled. */
+ testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
+ jz L(skip_ssp)
+# else
+ xorl %ecx, %ecx
+# endif
+ /* Get the current Shadow-Stack-Pointer and save it. */
+ rdsspd %ecx
+ movl %ecx, SHADOW_STACK_POINTER_OFFSET(%eax)
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+L(skip_ssp):
+# endif
+#endif
/* Call __sigjmp_save. */
pushl $1
diff --git a/sysdeps/i386/setjmp.S b/sysdeps/i386/setjmp.S
index 6a08701717..889337b8ae 100644
--- a/sysdeps/i386/setjmp.S
+++ b/sysdeps/i386/setjmp.S
@@ -18,6 +18,7 @@
#include <sysdep.h>
#include <jmpbuf-offsets.h>
+#include <jmp_buf-ssp.h>
#include <asm-syntax.h>
#include <stap-probe.h>
@@ -25,6 +26,11 @@
#define JMPBUF PARMS
#define SIGMSK JMPBUF+4
+/* Don't save shadow stack register if shadow stack isn't enabled. */
+#if !SHSTK_ENABLED
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
+
ENTRY (__sigsetjmp)
movl JMPBUF(%esp), %eax
@@ -46,6 +52,21 @@ ENTRY (__sigsetjmp)
movl %ecx, (JB_PC*4)(%eax)
movl %ebp, (JB_BP*4)(%eax) /* Save caller's frame pointer. */
+#ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+ /* Check if Shadow Stack is enabled. */
+ testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
+ jz L(skip_ssp)
+# else
+ xorl %ecx, %ecx
+# endif
+ /* Get the current Shadow-Stack-Pointer and save it. */
+ rdsspd %ecx
+ movl %ecx, SHADOW_STACK_POINTER_OFFSET(%eax)
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+L(skip_ssp):
+# endif
+#endif
#if IS_IN (rtld)
/* In ld.so we never save the signal mask. */
xorl %eax, %eax
diff --git a/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S b/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
index 3452433112..a7640d9892 100644
--- a/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
+++ b/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
@@ -17,9 +17,14 @@
#include <sysdep.h>
#include <jmpbuf-offsets.h>
+#include <jmp_buf-ssp.h>
#include <asm-syntax.h>
#include <stap-probe.h>
+/* Don't restore shadow stack register if shadow stack isn't enabled. */
+#if !SHSTK_ENABLED
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
.section .rodata.str1.1,"aMS",@progbits,1
.type longjmp_msg,@object
@@ -46,6 +51,38 @@ longjmp_msg:
ENTRY (____longjmp_chk)
movl 4(%esp), %ecx /* User's jmp_buf in %ecx. */
+#ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+ /* Check if Shadow Stack is enabled. */
+ testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
+ jz L(skip_ssp)
+# else
+ xorl %edx, %edx
+# endif
+ /* Check and adjust the Shadow-Stack-Pointer. */
+ rdsspd %edx
+ /* And compare it with the saved ssp value. */
+ subl SHADOW_STACK_POINTER_OFFSET(%ecx), %edx
+ je L(skip_ssp)
+ /* Count the number of frames to adjust and adjust it
+ with incssp instruction. The instruction can adjust
+ the ssp by [0..255] value only thus use a loop if
+ the number of frames is bigger than 255. */
+ negl %edx
+ shrl $2, %edx
+ /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
+ restoring Shadow-Stack-Pointer of setjmp's caller, we
+ need to unwind shadow stack by one more frame. */
+ addl $1, %edx
+ movl $255, %ebx
+L(loop):
+ cmpl %ebx, %edx
+ cmovb %edx, %ebx
+ incsspd %ebx
+ subl %ebx, %edx
+ ja L(loop)
+L(skip_ssp):
+#endif
/* Save the return address now. */
movl (JB_PC*4)(%ecx), %edx
/* Get the stack pointer. */
diff --git a/sysdeps/unix/sysv/linux/x86/Makefile b/sysdeps/unix/sysv/linux/x86/Makefile
index c55a43e58d..111ff9ff58 100644
--- a/sysdeps/unix/sysv/linux/x86/Makefile
+++ b/sysdeps/unix/sysv/linux/x86/Makefile
@@ -21,6 +21,5 @@ sysdep_routines += dl-vdso
endif
ifeq ($(subdir),setjmp)
-gen-as-const-headers += jmp_buf-ssp.sym
tests += tst-saved_mask-1
endif
diff --git a/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S b/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
index 8a9f2e1a3c..7eb26fafca 100644
--- a/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
+++ b/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
@@ -20,7 +20,13 @@
#include <asm-syntax.h>
#include <stap-probe.h>
+/* Don't restore shadow stack register if shadow stack isn't enabled. */
+#if !SHSTK_ENABLED
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
+
#include <sigaltstack-offsets.h>
+#include <jmp_buf-ssp.h>
.section .rodata.str1.1,"aMS",@progbits,1
.type longjmp_msg,@object
@@ -105,6 +111,38 @@ ENTRY(____longjmp_chk)
cfi_restore (%rsi)
.Lok:
+#ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+ /* Check if Shadow Stack is enabled. */
+ testl $X86_FEATURE_1_SHSTK, %fs:FEATURE_1_OFFSET
+ jz L(skip_ssp)
+# else
+ xorl %eax, %eax
+# endif
+ /* Check and adjust the Shadow-Stack-Pointer. */
+ rdsspq %rax
+ /* And compare it with the saved ssp value. */
+ subq SHADOW_STACK_POINTER_OFFSET(%rdi), %rax
+ je L(skip_ssp)
+ /* Count the number of frames to adjust and adjust it
+ with incssp instruction. The instruction can adjust
+ the ssp by [0..255] value only thus use a loop if
+ the number of frames is bigger than 255. */
+ negq %rax
+ shrq $3, %rax
+ /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
+ restoring Shadow-Stack-Pointer of setjmp's caller, we
+ need to unwind shadow stack by one more frame. */
+ addq $1, %rax
+ movl $255, %ebx
+L(loop):
+ cmpq %rbx, %rax
+ cmovb %rax, %rbx
+ incsspq %rbx
+ subq %rbx, %rax
+ ja L(loop)
+L(skip_ssp):
+#endif
LIBC_PROBE (longjmp, 3, LP_SIZE@%RDI_LP, -4@%esi, LP_SIZE@%RDX_LP)
/* We add unwind information for the target here. */
cfi_def_cfa(%rdi, 0)
diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
index d25d6f0ae4..65292f4032 100644
--- a/sysdeps/x86/Makefile
+++ b/sysdeps/x86/Makefile
@@ -10,5 +10,6 @@ tests-static += tst-get-cpu-features-static
endif
ifeq ($(subdir),setjmp)
+gen-as-const-headers += jmp_buf-ssp.sym
sysdep_routines += __longjmp_cancel
endif
diff --git a/sysdeps/x86/jmp_buf-ssp.sym b/sysdeps/x86/jmp_buf-ssp.sym
new file mode 100644
index 0000000000..1aaaedc9ec
--- /dev/null
+++ b/sysdeps/x86/jmp_buf-ssp.sym
@@ -0,0 +1 @@
+-- FIXME: Define SHADOW_STACK_POINTER_OFFSET to support shadow stack.
diff --git a/sysdeps/x86_64/__longjmp.S b/sysdeps/x86_64/__longjmp.S
index a487e0efd0..d7d123e4bc 100644
--- a/sysdeps/x86_64/__longjmp.S
+++ b/sysdeps/x86_64/__longjmp.S
@@ -17,9 +17,18 @@
#include <sysdep.h>
#include <jmpbuf-offsets.h>
+#include <jmp_buf-ssp.h>
#include <asm-syntax.h>
#include <stap-probe.h>
+/* Don't restore shadow stack register if
+ 1. Shadow stack isn't enabled. Or
+ 2. __longjmp is defined for __longjmp_cancel.
+ */
+#if !SHSTK_ENABLED || defined __longjmp
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
+
/* Jump to the position specified by ENV, causing the
setjmp call there to return VAL, or 1 if VAL is 0.
void __longjmp (__jmp_buf env, int val). */
@@ -41,6 +50,41 @@ ENTRY(__longjmp)
shlq $32, %rax
orq %rax, %r9
# endif
+#endif
+#ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+ /* Check if Shadow Stack is enabled. */
+ testl $X86_FEATURE_1_SHSTK, %fs:FEATURE_1_OFFSET
+ jz L(skip_ssp)
+# else
+ xorl %eax, %eax
+# endif
+ /* Check and adjust the Shadow-Stack-Pointer. */
+ /* Get the current ssp. */
+ rdsspq %rax
+ /* And compare it with the saved ssp value. */
+ subq SHADOW_STACK_POINTER_OFFSET(%rdi), %rax
+ je L(skip_ssp)
+ /* Count the number of frames to adjust and adjust it
+ with incssp instruction. The instruction can adjust
+ the ssp by [0..255] value only thus use a loop if
+ the number of frames is bigger than 255. */
+ negq %rax
+ shrq $3, %rax
+ /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
+ restoring Shadow-Stack-Pointer of setjmp's caller, we
+ need to unwind shadow stack by one more frame. */
+ addq $1, %rax
+
+ movl $255, %ebx
+L(loop):
+ cmpq %rbx, %rax
+ cmovb %rax, %rbx
+ incsspq %rbx
+ subq %rbx, %rax
+ ja L(loop)
+
+L(skip_ssp):
#endif
LIBC_PROBE (longjmp, 3, LP_SIZE@%RDI_LP, -4@%esi, LP_SIZE@%RDX_LP)
/* We add unwind information for the target here. */
diff --git a/sysdeps/x86_64/setjmp.S b/sysdeps/x86_64/setjmp.S
index e0a648e3e4..78a8bf4644 100644
--- a/sysdeps/x86_64/setjmp.S
+++ b/sysdeps/x86_64/setjmp.S
@@ -18,9 +18,15 @@
#include <sysdep.h>
#include <jmpbuf-offsets.h>
+#include <jmp_buf-ssp.h>
#include <asm-syntax.h>
#include <stap-probe.h>
+/* Don't save shadow stack register if shadow stack isn't enabled. */
+#if !SHSTK_ENABLED
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
+
ENTRY (__sigsetjmp)
/* Save registers. */
movq %rbx, (JB_RBX*8)(%rdi)
@@ -54,6 +60,21 @@ ENTRY (__sigsetjmp)
#endif
movq %rax, (JB_PC*8)(%rdi)
+#ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+ /* Check if Shadow Stack is enabled. */
+ testl $X86_FEATURE_1_SHSTK, %fs:FEATURE_1_OFFSET
+ jz L(skip_ssp)
+# else
+ xorl %eax, %eax
+# endif
+ /* Get the current Shadow-Stack-Pointer and save it. */
+ rdsspq %rax
+ movq %rax, SHADOW_STACK_POINTER_OFFSET(%rdi)
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+L(skip_ssp):
+# endif
+#endif
#if IS_IN (rtld)
/* In ld.so we never save the signal mask. */
xorl %eax, %eax
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* Re: V2: [PATCH 02/24] x86: Support shadow stack pointer in setjmp/longjmp
2018-07-13 13:23 ` V2: " H.J. Lu
@ 2018-07-13 18:49 ` Carlos O'Donell
2018-07-14 19:57 ` Florian Weimer
1 sibling, 0 replies; 54+ messages in thread
From: Carlos O'Donell @ 2018-07-13 18:49 UTC (permalink / raw)
To: H.J. Lu; +Cc: libc-alpha
On 07/13/2018 09:22 AM, H.J. Lu wrote:
> On Thu, Jul 12, 2018 at 02:13:21PM -0400, Carlos O'Donell wrote:
>> On 06/13/2018 11:31 AM, H.J. Lu wrote:
>>> Save and restore shadow stack pointer in setjmp and longjmp to support
>>> shadow stack in Intel CET. Use feature_1 in tcbhead_t to check if
>>> shadow stack is enabled before saving and restoring shadow stack
>>> pointer so that it works with the old smaller cancel_jmp_buf which
>>> doesn't have space for shadow stack pointer.
>>
>> This comment can't be accurate. For the older smaller cancel_jmp_buf
>> we found another way to solve this because you just don't restore the
>> shadowstack since we're jumping out through the unwinder. So we only
>> need this logically for setjmp/longjmp and *context functions?
>>
>> In general this is OK, I'd like to see a v2:
>>
>> - New accurate commit message.
>> - Replace (1 << 1) with meaningful macro constants that help a future
>> reader identify which FEATURE_1 flag we're looking at.
>>
>
> Done.
>
> ...
>>>
>>> +# ifdef SHADOW_STACK_POINTER_OFFSET
>>> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
>>> + /* Check if Shadow Stack is enabled. */
>>> + testl $(1 << 1), %gs:FEATURE_1_OFFSET
>>
>> Please replace all instances of "1" here with some kind of macro
>> that actually defines which flag we're checking.
>>
>
> I updated [PATCH 01/24] to add X86_FEATURE_1_IBT and X86_FEATURE_1_SHSTK
> in
>
> https://sourceware.org/ml/libc-alpha/2018-07/msg00375.html
>
> Here is the V2 patch. OK for master?
This is OK for master and 2.28.
Thanks for the update and cleanups.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
>
> H.J.
> ----
> Save and restore shadow stack pointer in setjmp and longjmp to support
> shadow stack in Intel CET. Use feature_1 in tcbhead_t to check if
> shadow stack is enabled before saving and restoring shadow stack pointer.
>
> 2017-12-07 Igor Tsimbalist <igor.v.tsimbalist@intel.com>
> H.J. Lu <hongjiu.lu@intel.com>
>
> * sysdeps/i386/__longjmp.S: Include <jmp_buf-ssp.h>.
> (__longjmp): Restore shadow stack pointer if shadow stack is
> enabled, SHADOW_STACK_POINTER_OFFSET is defined and __longjmp
> isn't defined for __longjmp_cancel.
> * sysdeps/i386/bsd-_setjmp.S: Include <jmp_buf-ssp.h>.
> (_setjmp): Save shadow stack pointer if shadow stack is enabled
> and SHADOW_STACK_POINTER_OFFSET is defined.
> * sysdeps/i386/bsd-setjmp.S: Include <jmp_buf-ssp.h>.
> (setjmp): Save shadow stack pointer if shadow stack is enabled
> and SHADOW_STACK_POINTER_OFFSET is defined.
> * sysdeps/i386/setjmp.S: Include <jmp_buf-ssp.h>.
> (__sigsetjmp): Save shadow stack pointer if shadow stack is
> enabled and SHADOW_STACK_POINTER_OFFSET is defined.
> * sysdeps/unix/sysv/linux/i386/____longjmp_chk.S: Include
> <jmp_buf-ssp.h>.
> (____longjmp_chk): Restore shadow stack pointer if shadow stack
> is enabled and SHADOW_STACK_POINTER_OFFSET is defined.
> * sysdeps/unix/sysv/linux/x86/Makefile (gen-as-const-headers):
> Remove jmp_buf-ssp.sym.
> * sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S: Include
> <jmp_buf-ssp.h>.
> (____longjmp_chk): Restore shadow stack pointer if shadow stack
> is enabled and SHADOW_STACK_POINTER_OFFSET is defined.
> * sysdeps/x86/Makefile (gen-as-const-headers): Add
> jmp_buf-ssp.sym.
> * sysdeps/x86/jmp_buf-ssp.sym: New dummy file.
> * sysdeps/x86_64/__longjmp.S: Include <jmp_buf-ssp.h>.
> (__longjmp): Restore shadow stack pointer if shadow stack is
> enabled, SHADOW_STACK_POINTER_OFFSET is defined and __longjmp
> isn't defined for __longjmp_cancel.
> * sysdeps/x86_64/setjmp.S: Include <jmp_buf-ssp.h>.
> (__sigsetjmp): Save shadow stack pointer if shadow stack is
> enabled and SHADOW_STACK_POINTER_OFFSET is defined.
> ---
> sysdeps/i386/__longjmp.S | 73 +++++++++++++++++++
> sysdeps/i386/bsd-_setjmp.S | 21 ++++++
> sysdeps/i386/bsd-setjmp.S | 21 ++++++
> sysdeps/i386/setjmp.S | 21 ++++++
> .../unix/sysv/linux/i386/____longjmp_chk.S | 37 ++++++++++
> sysdeps/unix/sysv/linux/x86/Makefile | 1 -
> .../unix/sysv/linux/x86_64/____longjmp_chk.S | 38 ++++++++++
> sysdeps/x86/Makefile | 1 +
> sysdeps/x86/jmp_buf-ssp.sym | 1 +
> sysdeps/x86_64/__longjmp.S | 44 +++++++++++
> sysdeps/x86_64/setjmp.S | 21 ++++++
> 11 files changed, 278 insertions(+), 1 deletion(-)
> create mode 100644 sysdeps/x86/jmp_buf-ssp.sym
>
> diff --git a/sysdeps/i386/__longjmp.S b/sysdeps/i386/__longjmp.S
> index b38333bead..6e98ed538d 100644
> --- a/sysdeps/i386/__longjmp.S
> +++ b/sysdeps/i386/__longjmp.S
> @@ -18,14 +18,55 @@
>
> #include <sysdep.h>
> #include <jmpbuf-offsets.h>
> +#include <jmp_buf-ssp.h>
> #include <asm-syntax.h>
> #include <stap-probe.h>
>
> +/* Don't restore shadow stack register if
> + 1. Shadow stack isn't enabled. Or
> + 2. __longjmp is defined for __longjmp_cancel.
> + */
> +#if !SHSTK_ENABLED || defined __longjmp
> +# undef SHADOW_STACK_POINTER_OFFSET
> +#endif
> +
> .text
> ENTRY (__longjmp)
> #ifdef PTR_DEMANGLE
> movl 4(%esp), %eax /* User's jmp_buf in %eax. */
>
> +# ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> + /* Check if Shadow Stack is enabled. */
> + testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
> + jz L(skip_ssp)
> +# else
> + xorl %edx, %edx
> +# endif
> + /* Check and adjust the Shadow-Stack-Pointer. */
> + rdsspd %edx
> + /* And compare it with the saved ssp value. */
> + subl SHADOW_STACK_POINTER_OFFSET(%eax), %edx
> + je L(skip_ssp)
> + /* Count the number of frames to adjust and adjust it
> + with incssp instruction. The instruction can adjust
> + the ssp by [0..255] value only thus use a loop if
> + the number of frames is bigger than 255. */
> + negl %edx
> + shrl $2, %edx
> + /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
> + restoring Shadow-Stack-Pointer of setjmp's caller, we
> + need to unwind shadow stack by one more frame. */
> + addl $1, %edx
> + movl $255, %ebx
> +L(loop):
> + cmpl %ebx, %edx
> + cmovb %edx, %ebx
> + incsspd %ebx
> + subl %ebx, %edx
> + ja L(loop)
> +L(skip_ssp):
> +# endif
> /* Save the return address now. */
> movl (JB_PC*4)(%eax), %edx
> /* Get the stack pointer. */
> @@ -56,6 +97,38 @@ ENTRY (__longjmp)
> #else
> movl 4(%esp), %ecx /* User's jmp_buf in %ecx. */
> movl 8(%esp), %eax /* Second argument is return value. */
> +# ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED
> + /* Check if Shadow Stack is enabled. */
> + testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
> + jz L(skip_ssp)
> +# endif
> + /* Check and adjust the Shadow-Stack-Pointer. */
> + xorl %edx, %edx
> + /* Get the current ssp. */
> + rdsspd %edx
> + /* And compare it with the saved ssp value. */
> + subl SHADOW_STACK_POINTER_OFFSET(%ecx), %edx
> + je L(skip_ssp)
> + /* Count the number of frames to adjust and adjust it
> + with incssp instruction. The instruction can adjust
> + the ssp by [0..255] value only thus use a loop if
> + the number of frames is bigger than 255. */
> + negl %edx
> + shrl $2, %edx
> + /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
> + restoring Shadow-Stack-Pointer of setjmp's caller, we
> + need to unwind shadow stack by one more frame. */
> + addl $1, %edx
> + movl $255, %ebx
> +L(loop):
> + cmpl %ebx, %edx
> + cmovb %edx, %ebx
> + incsspd %ebx
> + subl %ebx, %edx
> + ja L(loop)
> +L(skip_ssp):
> +# endif
> /* Save the return address now. */
> movl (JB_PC*4)(%ecx), %edx
> LIBC_PROBE (longjmp, 3, 4@%ecx, -4@%eax, 4@%edx)
> diff --git a/sysdeps/i386/bsd-_setjmp.S b/sysdeps/i386/bsd-_setjmp.S
> index a626cc6d22..db47df0ba1 100644
> --- a/sysdeps/i386/bsd-_setjmp.S
> +++ b/sysdeps/i386/bsd-_setjmp.S
> @@ -22,12 +22,18 @@
>
> #include <sysdep.h>
> #include <jmpbuf-offsets.h>
> +#include <jmp_buf-ssp.h>
> #include <stap-probe.h>
>
> #define PARMS 4 /* no space for saved regs */
> #define JMPBUF PARMS
> #define SIGMSK JMPBUF+4
>
> +/* Don't save shadow stack register if shadow stack isn't enabled. */
> +#if !SHSTK_ENABLED
> +# undef SHADOW_STACK_POINTER_OFFSET
> +#endif
> +
> ENTRY (_setjmp)
>
> xorl %eax, %eax
> @@ -51,6 +57,21 @@ ENTRY (_setjmp)
> movl %ebp, (JB_BP*4)(%edx) /* Save caller's frame pointer. */
>
> movl %eax, JB_SIZE(%edx) /* No signal mask set. */
> +#ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> + /* Check if Shadow Stack is enabled. */
> + testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
> + jz L(skip_ssp)
> +# else
> + xorl %ecx, %ecx
> +# endif
> + /* Get the current Shadow-Stack-Pointer and save it. */
> + rdsspd %ecx
> + movl %ecx, SHADOW_STACK_POINTER_OFFSET(%edx)
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> +L(skip_ssp):
> +# endif
> +#endif
> ret
> END (_setjmp)
> libc_hidden_def (_setjmp)
> diff --git a/sysdeps/i386/bsd-setjmp.S b/sysdeps/i386/bsd-setjmp.S
> index 2da8b73c49..1290d0d82b 100644
> --- a/sysdeps/i386/bsd-setjmp.S
> +++ b/sysdeps/i386/bsd-setjmp.S
> @@ -22,12 +22,18 @@
>
> #include <sysdep.h>
> #include <jmpbuf-offsets.h>
> +#include <jmp_buf-ssp.h>
> #include <stap-probe.h>
>
> #define PARMS 4 /* no space for saved regs */
> #define JMPBUF PARMS
> #define SIGMSK JMPBUF+4
>
> +/* Don't save shadow stack register if shadow stack isn't enabled. */
> +#if !SHSTK_ENABLED
> +# undef SHADOW_STACK_POINTER_OFFSET
> +#endif
> +
> ENTRY (setjmp)
> /* Note that we have to use a non-exported symbol in the next
> jump since otherwise gas will emit it as a jump through the
> @@ -51,6 +57,21 @@ ENTRY (setjmp)
> #endif
> movl %ecx, (JB_PC*4)(%eax)
> movl %ebp, (JB_BP*4)(%eax) /* Save caller's frame pointer. */
> +#ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> + /* Check if Shadow Stack is enabled. */
> + testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
> + jz L(skip_ssp)
> +# else
> + xorl %ecx, %ecx
> +# endif
> + /* Get the current Shadow-Stack-Pointer and save it. */
> + rdsspd %ecx
> + movl %ecx, SHADOW_STACK_POINTER_OFFSET(%eax)
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> +L(skip_ssp):
> +# endif
> +#endif
>
> /* Call __sigjmp_save. */
> pushl $1
> diff --git a/sysdeps/i386/setjmp.S b/sysdeps/i386/setjmp.S
> index 6a08701717..889337b8ae 100644
> --- a/sysdeps/i386/setjmp.S
> +++ b/sysdeps/i386/setjmp.S
> @@ -18,6 +18,7 @@
>
> #include <sysdep.h>
> #include <jmpbuf-offsets.h>
> +#include <jmp_buf-ssp.h>
> #include <asm-syntax.h>
> #include <stap-probe.h>
>
> @@ -25,6 +26,11 @@
> #define JMPBUF PARMS
> #define SIGMSK JMPBUF+4
>
> +/* Don't save shadow stack register if shadow stack isn't enabled. */
> +#if !SHSTK_ENABLED
> +# undef SHADOW_STACK_POINTER_OFFSET
> +#endif
> +
> ENTRY (__sigsetjmp)
>
> movl JMPBUF(%esp), %eax
> @@ -46,6 +52,21 @@ ENTRY (__sigsetjmp)
> movl %ecx, (JB_PC*4)(%eax)
> movl %ebp, (JB_BP*4)(%eax) /* Save caller's frame pointer. */
>
> +#ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> + /* Check if Shadow Stack is enabled. */
> + testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
> + jz L(skip_ssp)
> +# else
> + xorl %ecx, %ecx
> +# endif
> + /* Get the current Shadow-Stack-Pointer and save it. */
> + rdsspd %ecx
> + movl %ecx, SHADOW_STACK_POINTER_OFFSET(%eax)
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> +L(skip_ssp):
> +# endif
> +#endif
> #if IS_IN (rtld)
> /* In ld.so we never save the signal mask. */
> xorl %eax, %eax
> diff --git a/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S b/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
> index 3452433112..a7640d9892 100644
> --- a/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
> +++ b/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
> @@ -17,9 +17,14 @@
>
> #include <sysdep.h>
> #include <jmpbuf-offsets.h>
> +#include <jmp_buf-ssp.h>
> #include <asm-syntax.h>
> #include <stap-probe.h>
>
> +/* Don't restore shadow stack register if shadow stack isn't enabled. */
> +#if !SHSTK_ENABLED
> +# undef SHADOW_STACK_POINTER_OFFSET
> +#endif
>
> .section .rodata.str1.1,"aMS",@progbits,1
> .type longjmp_msg,@object
> @@ -46,6 +51,38 @@ longjmp_msg:
> ENTRY (____longjmp_chk)
> movl 4(%esp), %ecx /* User's jmp_buf in %ecx. */
>
> +#ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> + /* Check if Shadow Stack is enabled. */
> + testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
> + jz L(skip_ssp)
> +# else
> + xorl %edx, %edx
> +# endif
> + /* Check and adjust the Shadow-Stack-Pointer. */
> + rdsspd %edx
> + /* And compare it with the saved ssp value. */
> + subl SHADOW_STACK_POINTER_OFFSET(%ecx), %edx
> + je L(skip_ssp)
> + /* Count the number of frames to adjust and adjust it
> + with incssp instruction. The instruction can adjust
> + the ssp by [0..255] value only thus use a loop if
> + the number of frames is bigger than 255. */
> + negl %edx
> + shrl $2, %edx
> + /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
> + restoring Shadow-Stack-Pointer of setjmp's caller, we
> + need to unwind shadow stack by one more frame. */
> + addl $1, %edx
> + movl $255, %ebx
> +L(loop):
> + cmpl %ebx, %edx
> + cmovb %edx, %ebx
> + incsspd %ebx
> + subl %ebx, %edx
> + ja L(loop)
> +L(skip_ssp):
> +#endif
> /* Save the return address now. */
> movl (JB_PC*4)(%ecx), %edx
> /* Get the stack pointer. */
> diff --git a/sysdeps/unix/sysv/linux/x86/Makefile b/sysdeps/unix/sysv/linux/x86/Makefile
> index c55a43e58d..111ff9ff58 100644
> --- a/sysdeps/unix/sysv/linux/x86/Makefile
> +++ b/sysdeps/unix/sysv/linux/x86/Makefile
> @@ -21,6 +21,5 @@ sysdep_routines += dl-vdso
> endif
>
> ifeq ($(subdir),setjmp)
> -gen-as-const-headers += jmp_buf-ssp.sym
> tests += tst-saved_mask-1
> endif
> diff --git a/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S b/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
> index 8a9f2e1a3c..7eb26fafca 100644
> --- a/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
> +++ b/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
> @@ -20,7 +20,13 @@
> #include <asm-syntax.h>
> #include <stap-probe.h>
>
> +/* Don't restore shadow stack register if shadow stack isn't enabled. */
> +#if !SHSTK_ENABLED
> +# undef SHADOW_STACK_POINTER_OFFSET
> +#endif
> +
> #include <sigaltstack-offsets.h>
> +#include <jmp_buf-ssp.h>
>
> .section .rodata.str1.1,"aMS",@progbits,1
> .type longjmp_msg,@object
> @@ -105,6 +111,38 @@ ENTRY(____longjmp_chk)
> cfi_restore (%rsi)
>
> .Lok:
> +#ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> + /* Check if Shadow Stack is enabled. */
> + testl $X86_FEATURE_1_SHSTK, %fs:FEATURE_1_OFFSET
> + jz L(skip_ssp)
> +# else
> + xorl %eax, %eax
> +# endif
> + /* Check and adjust the Shadow-Stack-Pointer. */
> + rdsspq %rax
> + /* And compare it with the saved ssp value. */
> + subq SHADOW_STACK_POINTER_OFFSET(%rdi), %rax
> + je L(skip_ssp)
> + /* Count the number of frames to adjust and adjust it
> + with incssp instruction. The instruction can adjust
> + the ssp by [0..255] value only thus use a loop if
> + the number of frames is bigger than 255. */
> + negq %rax
> + shrq $3, %rax
> + /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
> + restoring Shadow-Stack-Pointer of setjmp's caller, we
> + need to unwind shadow stack by one more frame. */
> + addq $1, %rax
> + movl $255, %ebx
> +L(loop):
> + cmpq %rbx, %rax
> + cmovb %rax, %rbx
> + incsspq %rbx
> + subq %rbx, %rax
> + ja L(loop)
> +L(skip_ssp):
> +#endif
> LIBC_PROBE (longjmp, 3, LP_SIZE@%RDI_LP, -4@%esi, LP_SIZE@%RDX_LP)
> /* We add unwind information for the target here. */
> cfi_def_cfa(%rdi, 0)
> diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
> index d25d6f0ae4..65292f4032 100644
> --- a/sysdeps/x86/Makefile
> +++ b/sysdeps/x86/Makefile
> @@ -10,5 +10,6 @@ tests-static += tst-get-cpu-features-static
> endif
>
> ifeq ($(subdir),setjmp)
> +gen-as-const-headers += jmp_buf-ssp.sym
> sysdep_routines += __longjmp_cancel
> endif
> diff --git a/sysdeps/x86/jmp_buf-ssp.sym b/sysdeps/x86/jmp_buf-ssp.sym
> new file mode 100644
> index 0000000000..1aaaedc9ec
> --- /dev/null
> +++ b/sysdeps/x86/jmp_buf-ssp.sym
> @@ -0,0 +1 @@
> +-- FIXME: Define SHADOW_STACK_POINTER_OFFSET to support shadow stack.
> diff --git a/sysdeps/x86_64/__longjmp.S b/sysdeps/x86_64/__longjmp.S
> index a487e0efd0..d7d123e4bc 100644
> --- a/sysdeps/x86_64/__longjmp.S
> +++ b/sysdeps/x86_64/__longjmp.S
> @@ -17,9 +17,18 @@
>
> #include <sysdep.h>
> #include <jmpbuf-offsets.h>
> +#include <jmp_buf-ssp.h>
> #include <asm-syntax.h>
> #include <stap-probe.h>
>
> +/* Don't restore shadow stack register if
> + 1. Shadow stack isn't enabled. Or
> + 2. __longjmp is defined for __longjmp_cancel.
> + */
> +#if !SHSTK_ENABLED || defined __longjmp
> +# undef SHADOW_STACK_POINTER_OFFSET
> +#endif
> +
> /* Jump to the position specified by ENV, causing the
> setjmp call there to return VAL, or 1 if VAL is 0.
> void __longjmp (__jmp_buf env, int val). */
> @@ -41,6 +50,41 @@ ENTRY(__longjmp)
> shlq $32, %rax
> orq %rax, %r9
> # endif
> +#endif
> +#ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> + /* Check if Shadow Stack is enabled. */
> + testl $X86_FEATURE_1_SHSTK, %fs:FEATURE_1_OFFSET
> + jz L(skip_ssp)
> +# else
> + xorl %eax, %eax
> +# endif
> + /* Check and adjust the Shadow-Stack-Pointer. */
> + /* Get the current ssp. */
> + rdsspq %rax
> + /* And compare it with the saved ssp value. */
> + subq SHADOW_STACK_POINTER_OFFSET(%rdi), %rax
> + je L(skip_ssp)
> + /* Count the number of frames to adjust and adjust it
> + with incssp instruction. The instruction can adjust
> + the ssp by [0..255] value only thus use a loop if
> + the number of frames is bigger than 255. */
> + negq %rax
> + shrq $3, %rax
> + /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are
> + restoring Shadow-Stack-Pointer of setjmp's caller, we
> + need to unwind shadow stack by one more frame. */
> + addq $1, %rax
> +
> + movl $255, %ebx
> +L(loop):
> + cmpq %rbx, %rax
> + cmovb %rax, %rbx
> + incsspq %rbx
> + subq %rbx, %rax
> + ja L(loop)
> +
> +L(skip_ssp):
> #endif
> LIBC_PROBE (longjmp, 3, LP_SIZE@%RDI_LP, -4@%esi, LP_SIZE@%RDX_LP)
> /* We add unwind information for the target here. */
> diff --git a/sysdeps/x86_64/setjmp.S b/sysdeps/x86_64/setjmp.S
> index e0a648e3e4..78a8bf4644 100644
> --- a/sysdeps/x86_64/setjmp.S
> +++ b/sysdeps/x86_64/setjmp.S
> @@ -18,9 +18,15 @@
>
> #include <sysdep.h>
> #include <jmpbuf-offsets.h>
> +#include <jmp_buf-ssp.h>
> #include <asm-syntax.h>
> #include <stap-probe.h>
>
> +/* Don't save shadow stack register if shadow stack isn't enabled. */
> +#if !SHSTK_ENABLED
> +# undef SHADOW_STACK_POINTER_OFFSET
> +#endif
> +
> ENTRY (__sigsetjmp)
> /* Save registers. */
> movq %rbx, (JB_RBX*8)(%rdi)
> @@ -54,6 +60,21 @@ ENTRY (__sigsetjmp)
> #endif
> movq %rax, (JB_PC*8)(%rdi)
>
> +#ifdef SHADOW_STACK_POINTER_OFFSET
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> + /* Check if Shadow Stack is enabled. */
> + testl $X86_FEATURE_1_SHSTK, %fs:FEATURE_1_OFFSET
> + jz L(skip_ssp)
> +# else
> + xorl %eax, %eax
> +# endif
> + /* Get the current Shadow-Stack-Pointer and save it. */
> + rdsspq %rax
> + movq %rax, SHADOW_STACK_POINTER_OFFSET(%rdi)
> +# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
> +L(skip_ssp):
> +# endif
> +#endif
> #if IS_IN (rtld)
> /* In ld.so we never save the signal mask. */
> xorl %eax, %eax
>
^ permalink raw reply [flat|nested] 54+ messages in thread
* Re: V2: [PATCH 02/24] x86: Support shadow stack pointer in setjmp/longjmp
2018-07-13 13:23 ` V2: " H.J. Lu
2018-07-13 18:49 ` Carlos O'Donell
@ 2018-07-14 19:57 ` Florian Weimer
2018-07-14 21:03 ` H.J. Lu
1 sibling, 1 reply; 54+ messages in thread
From: Florian Weimer @ 2018-07-14 19:57 UTC (permalink / raw)
To: H.J. Lu; +Cc: Carlos O'Donell, libc-alpha
* H. J. Lu:
> + /* Get the current ssp. */
> + rdsspd %edx
This moves the required binutils version past current Debian's 2.28.
I know we recently increased the minimum make version recently, but
binutils 2.28 is still quite new, I think.
Could we list the bytes for the instruction explicitly instead?
^ permalink raw reply [flat|nested] 54+ messages in thread
* Re: V2: [PATCH 02/24] x86: Support shadow stack pointer in setjmp/longjmp
2018-07-14 19:57 ` Florian Weimer
@ 2018-07-14 21:03 ` H.J. Lu
2018-07-14 23:07 ` Florian Weimer
0 siblings, 1 reply; 54+ messages in thread
From: H.J. Lu @ 2018-07-14 21:03 UTC (permalink / raw)
To: Florian Weimer; +Cc: Carlos O'Donell, GNU C Library
On Sat, Jul 14, 2018 at 12:57 PM, Florian Weimer <fw@deneb.enyo.de> wrote:
> * H. J. Lu:
>
>> + /* Get the current ssp. */
>> + rdsspd %edx
>
> This moves the required binutils version past current Debian's 2.28.
>
> I know we recently increased the minimum make version recently, but
> binutils 2.28 is still quite new, I think.
>
> Could we list the bytes for the instruction explicitly instead?
The next patch:
https://sourceware.org/ml/libc-alpha/2018-07/msg00266.html
has sysdeps/x86/configure.ac:
if test x"$enable_cet" = xyes; then
# Check if CET can be enabled.
AC_CACHE_CHECK(whether CET can be enabled,
libc_cv_x86_cet_available, [dnl
cat > conftest.c <<EOF
#if !defined __CET__ || __CET__ != 3
# error CET isn't available.
#endif
EOF
if AC_TRY_COMMAND(${CC-cc} -c $CFLAGS -fcf-protection -include
cet.h conftest.c 1>&AS_MESSAGE_LOG_FD); then
libc_cv_x86_cet_available=yes
else
libc_cv_x86_cet_available=no
fi
rm -rf conftest*])
if test $libc_cv_x86_cet_available = yes; then
enable_cet=yes
else
if test x"$enable_cet" = xdefault; then
enable_cet=no
else
AC_MSG_ERROR([$CC doesn't support CET])
fi
fi
fi
if test $enable_cet = yes; then
# Check if assembler supports CET.
AC_CACHE_CHECK(whether $AS supports CET,
libc_cv_x86_cet_as, [dnl
cat > conftest.s <<EOF
incsspd %ecx
EOF
if AC_TRY_COMMAND(${CC-cc} -c $CFLAGS conftest.s -o conftest.o
1>&AS_MESSAGE_LOG_FD); then
libc_cv_x86_cet_as=yes
else
libc_cv_x86_cet_as=no
fi
rm -rf conftest*])
if test $libc_cv_x86_cet_as = no; then
AC_MSG_ERROR([$AS doesn't support CET])
fi
fi
LIBC_CONFIG_VAR([enable-cet], [$enable_cet])
You need GCC 8 and binutils with CET to enable CET. If you have an
older binutils or
GCC, you will get a configure error when --enable-cet is used.
--
H.J.
^ permalink raw reply [flat|nested] 54+ messages in thread* Re: V2: [PATCH 02/24] x86: Support shadow stack pointer in setjmp/longjmp
2018-07-14 21:03 ` H.J. Lu
@ 2018-07-14 23:07 ` Florian Weimer
2018-07-14 23:16 ` H.J. Lu
0 siblings, 1 reply; 54+ messages in thread
From: Florian Weimer @ 2018-07-14 23:07 UTC (permalink / raw)
To: H.J. Lu; +Cc: Carlos O'Donell, GNU C Library
* H. J. Lu:
> On Sat, Jul 14, 2018 at 12:57 PM, Florian Weimer <fw@deneb.enyo.de> wrote:
>> * H. J. Lu:
>>
>>> + /* Get the current ssp. */
>>> + rdsspd %edx
>>
>> This moves the required binutils version past current Debian's 2.28.
>>
>> I know we recently increased the minimum make version recently, but
>> binutils 2.28 is still quite new, I think.
>>
>> Could we list the bytes for the instruction explicitly instead?
>
> The next patch:
>
> https://sourceware.org/ml/libc-alpha/2018-07/msg00266.html
>
> has sysdeps/x86/configure.ac:
We currently have this (as of commit
faaee1f07ed25b2779bfd935ffb29f431b80d6d3):
==> sysdeps/unix/sysv/linux/x86/jmp_buf-ssp.sym <==
#include <setjmpP.h>
#undef __saved_mask
--
SHADOW_STACK_POINTER_OFFSET offsetof(struct __jmp_buf_tag, __saved_mask.__saved.__shadow_stack_pointer)
==> sysdeps/x86/jmp_buf-ssp.sym <==
-- FIXME: Define SHADOW_STACK_POINTER_OFFSET to support shadow stack.
So SHADOW_STACK_POINTER_OFFSET is defined unconditionally. I don't
see how the quoted patch changes that.
Making sure that rdssp is only assembled with --enable-cet looks like
the right solution, but you need something like #if ENABLE_CET, and
not depend on SHADOW_STACK_POINTER_OFFSET being defined.
^ permalink raw reply [flat|nested] 54+ messages in thread
* Re: V2: [PATCH 02/24] x86: Support shadow stack pointer in setjmp/longjmp
2018-07-14 23:07 ` Florian Weimer
@ 2018-07-14 23:16 ` H.J. Lu
2018-07-14 23:16 ` H.J. Lu
2018-07-15 8:07 ` Florian Weimer
0 siblings, 2 replies; 54+ messages in thread
From: H.J. Lu @ 2018-07-14 23:16 UTC (permalink / raw)
To: Florian Weimer; +Cc: Carlos O'Donell, GNU C Library
On Sat, Jul 14, 2018 at 4:07 PM, Florian Weimer <fw@deneb.enyo.de> wrote:
> * H. J. Lu:
>
>> On Sat, Jul 14, 2018 at 12:57 PM, Florian Weimer <fw@deneb.enyo.de> wrote:
>>> * H. J. Lu:
>>>
>>>> + /* Get the current ssp. */
>>>> + rdsspd %edx
>>>
>>> This moves the required binutils version past current Debian's 2.28.
>>>
>>> I know we recently increased the minimum make version recently, but
>>> binutils 2.28 is still quite new, I think.
>>>
>>> Could we list the bytes for the instruction explicitly instead?
>>
>> The next patch:
>>
>> https://sourceware.org/ml/libc-alpha/2018-07/msg00266.html
>>
>> has sysdeps/x86/configure.ac:
>
> We currently have this (as of commit
> faaee1f07ed25b2779bfd935ffb29f431b80d6d3):
>
> ==> sysdeps/unix/sysv/linux/x86/jmp_buf-ssp.sym <==
> #include <setjmpP.h>
> #undef __saved_mask
>
> --
> SHADOW_STACK_POINTER_OFFSET offsetof(struct __jmp_buf_tag, __saved_mask.__saved.__shadow_stack_pointer)
>
> ==> sysdeps/x86/jmp_buf-ssp.sym <==
> -- FIXME: Define SHADOW_STACK_POINTER_OFFSET to support shadow stack.
>
> So SHADOW_STACK_POINTER_OFFSET is defined unconditionally. I don't
> see how the quoted patch changes that.
>
> Making sure that rdssp is only assembled with --enable-cet looks like
> the right solution, but you need something like #if ENABLE_CET, and
> not depend on SHADOW_STACK_POINTER_OFFSET being defined.
Take sysdeps/x86_64/setjmp.S as example:
/* Don't save shadow stack register if shadow stack isn't enabled. */
#if !SHSTK_ENABLED
# undef SHADOW_STACK_POINTER_OFFSET
#endif
.....
Shadow stack pointer is saved/restored only if --enable-cet is used to
configure glibc. If you compile glibc with -fcf-protection, but without
configuring glibc with --enable-cet, result is undefined.
--
H.J.
^ permalink raw reply [flat|nested] 54+ messages in thread
* Re: V2: [PATCH 02/24] x86: Support shadow stack pointer in setjmp/longjmp
2018-07-14 23:16 ` H.J. Lu
@ 2018-07-14 23:16 ` H.J. Lu
2018-07-15 8:07 ` Florian Weimer
1 sibling, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-07-14 23:16 UTC (permalink / raw)
To: Florian Weimer; +Cc: Carlos O'Donell, GNU C Library
On Sat, Jul 14, 2018 at 4:15 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Sat, Jul 14, 2018 at 4:07 PM, Florian Weimer <fw@deneb.enyo.de> wrote:
>> * H. J. Lu:
>>
>>> On Sat, Jul 14, 2018 at 12:57 PM, Florian Weimer <fw@deneb.enyo.de> wrote:
>>>> * H. J. Lu:
>>>>
>>>>> + /* Get the current ssp. */
>>>>> + rdsspd %edx
>>>>
>>>> This moves the required binutils version past current Debian's 2.28.
>>>>
>>>> I know we recently increased the minimum make version recently, but
>>>> binutils 2.28 is still quite new, I think.
>>>>
>>>> Could we list the bytes for the instruction explicitly instead?
>>>
>>> The next patch:
>>>
>>> https://sourceware.org/ml/libc-alpha/2018-07/msg00266.html
>>>
>>> has sysdeps/x86/configure.ac:
>>
>> We currently have this (as of commit
>> faaee1f07ed25b2779bfd935ffb29f431b80d6d3):
>>
>> ==> sysdeps/unix/sysv/linux/x86/jmp_buf-ssp.sym <==
>> #include <setjmpP.h>
>> #undef __saved_mask
>>
>> --
>> SHADOW_STACK_POINTER_OFFSET offsetof(struct __jmp_buf_tag, __saved_mask.__saved.__shadow_stack_pointer)
>>
>> ==> sysdeps/x86/jmp_buf-ssp.sym <==
>> -- FIXME: Define SHADOW_STACK_POINTER_OFFSET to support shadow stack.
>>
>> So SHADOW_STACK_POINTER_OFFSET is defined unconditionally. I don't
>> see how the quoted patch changes that.
>>
>> Making sure that rdssp is only assembled with --enable-cet looks like
>> the right solution, but you need something like #if ENABLE_CET, and
>> not depend on SHADOW_STACK_POINTER_OFFSET being defined.
>
> Take sysdeps/x86_64/setjmp.S as example:
>
> /* Don't save shadow stack register if shadow stack isn't enabled. */
> #if !SHSTK_ENABLED
> # undef SHADOW_STACK_POINTER_OFFSET
> #endif
> .....
>
> Shadow stack pointer is saved/restored only if --enable-cet is used to
> configure glibc. If you compile glibc with -fcf-protection, but without
> configuring glibc with --enable-cet, result is undefined.
>
BTW, it passed build-many-glibcs.py.
--
H.J.
^ permalink raw reply [flat|nested] 54+ messages in thread
* Re: V2: [PATCH 02/24] x86: Support shadow stack pointer in setjmp/longjmp
2018-07-14 23:16 ` H.J. Lu
2018-07-14 23:16 ` H.J. Lu
@ 2018-07-15 8:07 ` Florian Weimer
2018-07-15 13:54 ` H.J. Lu
1 sibling, 1 reply; 54+ messages in thread
From: Florian Weimer @ 2018-07-15 8:07 UTC (permalink / raw)
To: H.J. Lu; +Cc: Carlos O'Donell, GNU C Library
* H. J. Lu:
>> We currently have this (as of commit
>> faaee1f07ed25b2779bfd935ffb29f431b80d6d3):
>>
>> ==> sysdeps/unix/sysv/linux/x86/jmp_buf-ssp.sym <==
>> #include <setjmpP.h>
>> #undef __saved_mask
>>
>> --
>> SHADOW_STACK_POINTER_OFFSET offsetof(struct __jmp_buf_tag,
>> __saved_mask.__saved.__shadow_stack_pointer)
>>
>> ==> sysdeps/x86/jmp_buf-ssp.sym <==
>> -- FIXME: Define SHADOW_STACK_POINTER_OFFSET to support shadow stack.
>>
>> So SHADOW_STACK_POINTER_OFFSET is defined unconditionally. I don't
>> see how the quoted patch changes that.
>>
>> Making sure that rdssp is only assembled with --enable-cet looks like
>> the right solution, but you need something like #if ENABLE_CET, and
>> not depend on SHADOW_STACK_POINTER_OFFSET being defined.
>
> Take sysdeps/x86_64/setjmp.S as example:
>
> /* Don't save shadow stack register if shadow stack isn't enabled. */
> #if !SHSTK_ENABLED
> # undef SHADOW_STACK_POINTER_OFFSET
> #endif
> .....
>
> Shadow stack pointer is saved/restored only if --enable-cet is used to
> configure glibc. If you compile glibc with -fcf-protection, but without
> configuring glibc with --enable-cet, result is undefined.
That doesn't work because <jmp_buf-ssp.h> is included after the
#undef. I think you can avoid that by using #if SHTSTK_ENABLED
instead of #ifdef SHADOW_STACK_POINTER_OFFSET, which also expresses
the intent more accurately.
> BTW, it passed build-many-glibcs.py.
With binutils 2.28?
^ permalink raw reply [flat|nested] 54+ messages in thread
* Re: V2: [PATCH 02/24] x86: Support shadow stack pointer in setjmp/longjmp
2018-07-15 8:07 ` Florian Weimer
@ 2018-07-15 13:54 ` H.J. Lu
2018-07-15 20:20 ` Florian Weimer
0 siblings, 1 reply; 54+ messages in thread
From: H.J. Lu @ 2018-07-15 13:54 UTC (permalink / raw)
To: Florian Weimer; +Cc: Carlos O'Donell, GNU C Library
On Sun, Jul 15, 2018 at 1:07 AM, Florian Weimer <fw@deneb.enyo.de> wrote:
> * H. J. Lu:
>
>>> We currently have this (as of commit
>>> faaee1f07ed25b2779bfd935ffb29f431b80d6d3):
>>>
>>> ==> sysdeps/unix/sysv/linux/x86/jmp_buf-ssp.sym <==
>>> #include <setjmpP.h>
>>> #undef __saved_mask
>>>
>>> --
>>> SHADOW_STACK_POINTER_OFFSET offsetof(struct __jmp_buf_tag,
>>> __saved_mask.__saved.__shadow_stack_pointer)
>>>
>>> ==> sysdeps/x86/jmp_buf-ssp.sym <==
>>> -- FIXME: Define SHADOW_STACK_POINTER_OFFSET to support shadow stack.
>>>
>>> So SHADOW_STACK_POINTER_OFFSET is defined unconditionally. I don't
>>> see how the quoted patch changes that.
>>>
>>> Making sure that rdssp is only assembled with --enable-cet looks like
>>> the right solution, but you need something like #if ENABLE_CET, and
>>> not depend on SHADOW_STACK_POINTER_OFFSET being defined.
>>
>> Take sysdeps/x86_64/setjmp.S as example:
>>
>> /* Don't save shadow stack register if shadow stack isn't enabled. */
>> #if !SHSTK_ENABLED
>> # undef SHADOW_STACK_POINTER_OFFSET
>> #endif
>> .....
>>
>> Shadow stack pointer is saved/restored only if --enable-cet is used to
>> configure glibc. If you compile glibc with -fcf-protection, but without
>> configuring glibc with --enable-cet, result is undefined.
>
> That doesn't work because <jmp_buf-ssp.h> is included after the
You are right. sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S checks
SHTSTK_ENABLED after <jmp_buf-ssp.h> is included.
> #undef. I think you can avoid that by using #if SHTSTK_ENABLED
> instead of #ifdef SHADOW_STACK_POINTER_OFFSET, which also expresses
> the intent more accurately.
It is done on purpose. sysdeps/x86_64/__longjmp.S has
/* Don't restore shadow stack register if
1. Shadow stack isn't enabled. Or
2. __longjmp is defined for __longjmp_cancel.
*/
#if !SHSTK_ENABLED || defined __longjmp
# undef SHADOW_STACK_POINTER_OFFSET
#endif
>> BTW, it passed build-many-glibcs.py.
>
> With binutils 2.28?
I am checking in this patch. Tested with build-many-glibcs.py using
binutils 2.28.
--
H.J.
---
From 338ee814e778c38ca57a02c76056cba978205b95 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Sun, 15 Jul 2018 06:07:52 -0700
Subject: [PATCH] x86_64: Undef SHADOW_STACK_POINTER_OFFSET last
Since SHADOW_STACK_POINTER_OFFSET is defined in jmp_buf-ssp.h, we must
undef SHADOW_STACK_POINTER_OFFSET after including <jmp_buf-ssp.h>.
* sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S: Undef
SHADOW_STACK_POINTER_OFFSET after including <jmp_buf-ssp.h>.
---
sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
b/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
index 7eb26fafca..5d2d275721 100644
--- a/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
+++ b/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
@@ -19,15 +19,14 @@
#include <jmpbuf-offsets.h>
#include <asm-syntax.h>
#include <stap-probe.h>
+#include <sigaltstack-offsets.h>
+#include <jmp_buf-ssp.h>
/* Don't restore shadow stack register if shadow stack isn't enabled. */
#if !SHSTK_ENABLED
# undef SHADOW_STACK_POINTER_OFFSET
#endif
-#include <sigaltstack-offsets.h>
-#include <jmp_buf-ssp.h>
-
.section .rodata.str1.1,"aMS",@progbits,1
.type longjmp_msg,@object
longjmp_msg:
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread
* Re: V2: [PATCH 02/24] x86: Support shadow stack pointer in setjmp/longjmp
2018-07-15 13:54 ` H.J. Lu
@ 2018-07-15 20:20 ` Florian Weimer
2018-07-15 22:01 ` H.J. Lu
0 siblings, 1 reply; 54+ messages in thread
From: Florian Weimer @ 2018-07-15 20:20 UTC (permalink / raw)
To: H.J. Lu; +Cc: Carlos O'Donell, GNU C Library
* H. J. Lu:
>> #undef. I think you can avoid that by using #if SHTSTK_ENABLED
>> instead of #ifdef SHADOW_STACK_POINTER_OFFSET, which also expresses
>> the intent more accurately.
>
> It is done on purpose. sysdeps/x86_64/__longjmp.S has
>
> /* Don't restore shadow stack register if
> 1. Shadow stack isn't enabled. Or
> 2. __longjmp is defined for __longjmp_cancel.
> */
> #if !SHSTK_ENABLED || defined __longjmp
> # undef SHADOW_STACK_POINTER_OFFSET
> #endif
It's a bit awkward.
> Subject: [PATCH] x86_64: Undef SHADOW_STACK_POINTER_OFFSET last
>
> Since SHADOW_STACK_POINTER_OFFSET is defined in jmp_buf-ssp.h, we must
> undef SHADOW_STACK_POINTER_OFFSET after including <jmp_buf-ssp.h>.
>
> * sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S: Undef
> SHADOW_STACK_POINTER_OFFSET after including <jmp_buf-ssp.h>.
This looks okay as a fix.
^ permalink raw reply [flat|nested] 54+ messages in thread
* Re: V2: [PATCH 02/24] x86: Support shadow stack pointer in setjmp/longjmp
2018-07-15 20:20 ` Florian Weimer
@ 2018-07-15 22:01 ` H.J. Lu
0 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-07-15 22:01 UTC (permalink / raw)
To: Florian Weimer; +Cc: Carlos O'Donell, GNU C Library
On Sun, Jul 15, 2018 at 12:22 PM, Florian Weimer <fw@deneb.enyo.de> wrote:
> * H. J. Lu:
>
>>> #undef. I think you can avoid that by using #if SHTSTK_ENABLED
>>> instead of #ifdef SHADOW_STACK_POINTER_OFFSET, which also expresses
>>> the intent more accurately.
>>
>> It is done on purpose. sysdeps/x86_64/__longjmp.S has
>>
>> /* Don't restore shadow stack register if
>> 1. Shadow stack isn't enabled. Or
>> 2. __longjmp is defined for __longjmp_cancel.
>> */
>> #if !SHSTK_ENABLED || defined __longjmp
>> # undef SHADOW_STACK_POINTER_OFFSET
>> #endif
>
> It's a bit awkward.
Linux and Hurd share the same implementation of setjmp/longjmp. But
1. For Linux, SHADOW_STACK_POINTER_OFFSET is always defined regardless if
CET is enabled.
2.For Hurd, SHADOW_STACK_POINTER_OFFSET is undefined since it is unknown
how to save shadow stack pointer.
3. When CET is enabled, setjmp/longjmp is assembled twice. One preserves
shadow stack pointer and the other doesn't. Both versions support IBT.
4. All assembly files are compiled with the same compiler options.
SHADOW_STACK_POINTER_OFFSET is used to control if shadow stack pointer
should be preserved:
1. If CET isn't enabled, undef SHADOW_STACK_POINTER_OFFSET.
2. If CET is enabled, undef SHADOW_STACK_POINTER_OFFSET when not to
preserve shadow stack pointer.
>> Subject: [PATCH] x86_64: Undef SHADOW_STACK_POINTER_OFFSET last
>>
>> Since SHADOW_STACK_POINTER_OFFSET is defined in jmp_buf-ssp.h, we must
>> undef SHADOW_STACK_POINTER_OFFSET after including <jmp_buf-ssp.h>.
>>
>> * sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S: Undef
>> SHADOW_STACK_POINTER_OFFSET after including <jmp_buf-ssp.h>.
>
> This looks okay as a fix.
I will check it in.
Thanks.
--
H.J.
^ permalink raw reply [flat|nested] 54+ messages in thread
* [PATCH 04/24] x86: Add _CET_ENDBR to functions in crti.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (16 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 02/24] x86: Support shadow stack pointer in setjmp/longjmp H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-07-06 14:50 ` Carlos O'Donell
2018-06-13 15:32 ` [PATCH 19/24] i386: Use _CET_NOTRACK in memcpy-ssse3.S H.J. Lu
` (6 subsequent siblings)
24 siblings, 1 reply; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
Add _CET_ENDBR to functions in crti.S, which are called indirectly, to
support IBT.
Tested on i686 and x86-64.
* sysdeps/i386/crti.S (_init): Add _CET_ENDBR.
(_fini): Likewise.
* sysdeps/x86_64/crti.S (_init): Likewise.
(_fini): Likewise.
---
sysdeps/i386/crti.S | 2 ++
sysdeps/x86_64/crti.S | 2 ++
2 files changed, 4 insertions(+)
diff --git a/sysdeps/i386/crti.S b/sysdeps/i386/crti.S
index ffbc92c22f..65ddc1c934 100644
--- a/sysdeps/i386/crti.S
+++ b/sysdeps/i386/crti.S
@@ -61,6 +61,7 @@
.hidden _init
.type _init, @function
_init:
+ _CET_ENDBR
pushl %ebx
/* Maintain 16-byte stack alignment for called functions. */
subl $8, %esp
@@ -81,6 +82,7 @@ _init:
.hidden _fini
.type _fini, @function
_fini:
+ _CET_ENDBR
pushl %ebx
subl $8, %esp
LOAD_PIC_REG (bx)
diff --git a/sysdeps/x86_64/crti.S b/sysdeps/x86_64/crti.S
index f26915e956..067ac14884 100644
--- a/sysdeps/x86_64/crti.S
+++ b/sysdeps/x86_64/crti.S
@@ -61,6 +61,7 @@
.hidden _init
.type _init, @function
_init:
+ _CET_ENDBR
/* Maintain 16-byte stack alignment for called functions. */
subq $8, %rsp
#if PREINIT_FUNCTION_WEAK
@@ -79,4 +80,5 @@ _init:
.hidden _fini
.type _fini, @function
_fini:
+ _CET_ENDBR
subq $8, %rsp
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* Re: [PATCH 04/24] x86: Add _CET_ENDBR to functions in crti.S
2018-06-13 15:32 ` [PATCH 04/24] x86: Add _CET_ENDBR to functions in crti.S H.J. Lu
@ 2018-07-06 14:50 ` Carlos O'Donell
2018-07-06 17:01 ` H.J. Lu
0 siblings, 1 reply; 54+ messages in thread
From: Carlos O'Donell @ 2018-07-06 14:50 UTC (permalink / raw)
To: H.J. Lu, libc-alpha
On 06/13/2018 11:31 AM, H.J. Lu wrote:
> Add _CET_ENDBR to functions in crti.S, which are called indirectly, to
> support IBT.
>
> Tested on i686 and x86-64.
>
> * sysdeps/i386/crti.S (_init): Add _CET_ENDBR.
> (_fini): Likewise.
> * sysdeps/x86_64/crti.S (_init): Likewise.
> (_fini): Likewise.
Please commit.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
> ---
> sysdeps/i386/crti.S | 2 ++
> sysdeps/x86_64/crti.S | 2 ++
> 2 files changed, 4 insertions(+)
>
> diff --git a/sysdeps/i386/crti.S b/sysdeps/i386/crti.S
> index ffbc92c22f..65ddc1c934 100644
> --- a/sysdeps/i386/crti.S
> +++ b/sysdeps/i386/crti.S
> @@ -61,6 +61,7 @@
> .hidden _init
> .type _init, @function
> _init:
> + _CET_ENDBR
> pushl %ebx
> /* Maintain 16-byte stack alignment for called functions. */
> subl $8, %esp
> @@ -81,6 +82,7 @@ _init:
> .hidden _fini
> .type _fini, @function
> _fini:
> + _CET_ENDBR
> pushl %ebx
> subl $8, %esp
> LOAD_PIC_REG (bx)
> diff --git a/sysdeps/x86_64/crti.S b/sysdeps/x86_64/crti.S
> index f26915e956..067ac14884 100644
> --- a/sysdeps/x86_64/crti.S
> +++ b/sysdeps/x86_64/crti.S
> @@ -61,6 +61,7 @@
> .hidden _init
> .type _init, @function
> _init:
> + _CET_ENDBR
> /* Maintain 16-byte stack alignment for called functions. */
> subq $8, %rsp
> #if PREINIT_FUNCTION_WEAK
> @@ -79,4 +80,5 @@ _init:
> .hidden _fini
> .type _fini, @function
> _fini:
> + _CET_ENDBR
> subq $8, %rsp
>
--
Cheers,
Carlos.
^ permalink raw reply [flat|nested] 54+ messages in thread
* Re: [PATCH 04/24] x86: Add _CET_ENDBR to functions in crti.S
2018-07-06 14:50 ` Carlos O'Donell
@ 2018-07-06 17:01 ` H.J. Lu
2018-07-06 18:48 ` Carlos O'Donell
0 siblings, 1 reply; 54+ messages in thread
From: H.J. Lu @ 2018-07-06 17:01 UTC (permalink / raw)
To: Carlos O'Donell; +Cc: GNU C Library
On Fri, Jul 6, 2018 at 7:50 AM, Carlos O'Donell <carlos@redhat.com> wrote:
> On 06/13/2018 11:31 AM, H.J. Lu wrote:
>> Add _CET_ENDBR to functions in crti.S, which are called indirectly, to
>> support IBT.
>>
>> Tested on i686 and x86-64.
>>
>> * sysdeps/i386/crti.S (_init): Add _CET_ENDBR.
>> (_fini): Likewise.
>> * sysdeps/x86_64/crti.S (_init): Likewise.
>> (_fini): Likewise.
>
> Please commit.
>
> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
>
All my _CET_ENDBR changes depend on:
https://sourceware.org/ml/libc-alpha/2018-06/msg00325.html
--
H.J.
^ permalink raw reply [flat|nested] 54+ messages in thread
* Re: [PATCH 04/24] x86: Add _CET_ENDBR to functions in crti.S
2018-07-06 17:01 ` H.J. Lu
@ 2018-07-06 18:48 ` Carlos O'Donell
0 siblings, 0 replies; 54+ messages in thread
From: Carlos O'Donell @ 2018-07-06 18:48 UTC (permalink / raw)
To: H.J. Lu; +Cc: GNU C Library
On 07/06/2018 01:00 PM, H.J. Lu wrote:
> On Fri, Jul 6, 2018 at 7:50 AM, Carlos O'Donell <carlos@redhat.com> wrote:
>> On 06/13/2018 11:31 AM, H.J. Lu wrote:
>>> Add _CET_ENDBR to functions in crti.S, which are called indirectly, to
>>> support IBT.
>>>
>>> Tested on i686 and x86-64.
>>>
>>> * sysdeps/i386/crti.S (_init): Add _CET_ENDBR.
>>> (_fini): Likewise.
>>> * sysdeps/x86_64/crti.S (_init): Likewise.
>>> (_fini): Likewise.
>>
>> Please commit.
>>
>> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
>>
>
> All my _CET_ENDBR changes depend on:
>
> https://sourceware.org/ml/libc-alpha/2018-06/msg00325.html
Understood, and I'm reviewing that one still.
--
Cheers,
Carlos.
^ permalink raw reply [flat|nested] 54+ messages in thread
* [PATCH 19/24] i386: Use _CET_NOTRACK in memcpy-ssse3.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (17 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 04/24] x86: Add _CET_ENDBR to functions in crti.S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-06-13 15:32 ` [PATCH 08/24] x86: Update vfork to pop shadow stack H.J. Lu
` (5 subsequent siblings)
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
* sysdeps/i386/i686/multiarch/memcpy-ssse3.S
(BRANCH_TO_JMPTBL_ENTRY): Add _CET_NOTRACK before indirect jump
to jump table.
---
sysdeps/i386/i686/multiarch/memcpy-ssse3.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/sysdeps/i386/i686/multiarch/memcpy-ssse3.S b/sysdeps/i386/i686/multiarch/memcpy-ssse3.S
index bb35c4c2b7..5ead569a5e 100644
--- a/sysdeps/i386/i686/multiarch/memcpy-ssse3.S
+++ b/sysdeps/i386/i686/multiarch/memcpy-ssse3.S
@@ -71,7 +71,7 @@
absolute address. */ \
addl (%ebx, INDEX, SCALE), %ebx; \
/* We loaded the jump table. Go. */ \
- jmp *%ebx
+ _CET_NOTRACK jmp *%ebx
# else
# define PARMS 4
@@ -85,7 +85,7 @@
jump table. SCALE is the scale of INDEX. */
# define BRANCH_TO_JMPTBL_ENTRY(TABLE, INDEX, SCALE) \
- jmp *TABLE(, INDEX, SCALE)
+ _CET_NOTRACK jmp *TABLE(, INDEX, SCALE)
# endif
.section .text.ssse3,"ax",@progbits
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* [PATCH 08/24] x86: Update vfork to pop shadow stack
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (18 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 19/24] i386: Use _CET_NOTRACK in memcpy-ssse3.S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-06-13 15:32 ` [PATCH 14/24] x86-64: Use _CET_NOTRACK in memcpy-ssse3.S H.J. Lu
` (4 subsequent siblings)
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
Since we can't change return address on shadow stack, if shadow stack
is in use, we need to pop shadow stack and jump back to caller directly.
* sysdeps/unix/sysv/linux/i386/vfork.S (SYSCALL_ERROR_HANDLER):
Redefine if shadow stack is enabled.
(SYSCALL_ERROR_LABEL): Likewise.
(__vfork): Pop shadow stack and jump back to to caller directly
when shadow stack is in use.
* sysdeps/unix/sysv/linux/x86_64/vfork.S (SYSCALL_ERROR_HANDLER):
Redefine if shadow stack is enabled.
(SYSCALL_ERROR_LABEL): Likewise.
(__vfork): Pop shadow stack and jump back to to caller directly
when shadow stack is in use.
---
sysdeps/unix/sysv/linux/i386/vfork.S | 54 ++++++++++++++++++++++++++
sysdeps/unix/sysv/linux/x86_64/vfork.S | 35 +++++++++++++++++
2 files changed, 89 insertions(+)
diff --git a/sysdeps/unix/sysv/linux/i386/vfork.S b/sysdeps/unix/sysv/linux/i386/vfork.S
index 8f40d02d09..06d834d632 100644
--- a/sysdeps/unix/sysv/linux/i386/vfork.S
+++ b/sysdeps/unix/sysv/linux/i386/vfork.S
@@ -21,6 +21,35 @@
#include <bits/errno.h>
#include <tcb-offsets.h>
+#if defined __CET__ && (__CET__ & 2) != 0
+/* When shadow stack is in use, we need to pop shadow stack and jump
+ back to caller directly. */
+# undef SYSCALL_ERROR_HANDLER
+# ifdef PIC
+# define SYSCALL_ERROR_HANDLER \
+0: \
+ calll .L1; \
+.L1: \
+ popl %edx; \
+.L2: \
+ addl $_GLOBAL_OFFSET_TABLE_ + (.L2 - .L1), %edx; \
+ movl __libc_errno@gotntpoff(%edx), %edx; \
+ negl %eax; \
+ movl %eax, %gs:(%edx); \
+ orl $-1, %eax; \
+ jmp 1b;
+# else
+# define SYSCALL_ERROR_HANDLER \
+0: \
+ movl __libc_errno@indntpoff, %edx; \
+ negl %eax; \
+ movl %eax, %gs:(%edx); \
+ orl $-1, %eax; \
+ jmp 1b;
+# endif
+# undef SYSCALL_ERROR_LABEL
+# define SYSCALL_ERROR_LABEL 0f
+#endif
/* Clone the calling process, but without copying the whole address space.
The calling process is suspended until the new process exits or is
@@ -38,16 +67,41 @@ ENTRY (__vfork)
movl $SYS_ify (vfork), %eax
int $0x80
+#if !defined __CET__ || (__CET__ & 2) == 0
/* Jump to the return PC. Don't jump directly since this
disturbs the branch target cache. Instead push the return
address back on the stack. */
pushl %ecx
cfi_adjust_cfa_offset (4)
+#endif
cmpl $-4095, %eax
/* Branch forward if it failed. */
jae SYSCALL_ERROR_LABEL
+#if defined __CET__ && (__CET__ & 2) != 0
+1:
+ /* Check if shadow stack is in use. */
+ xorl %edx, %edx
+ rdsspd %edx
+ testl %edx, %edx
+ /* Normal return if shadow stack isn't in use. */
+ je L(no_shstk)
+
+ /* Pop return address from shadow stack and jump back to caller
+ directly. */
+ movl $1, %edx
+ incsspd %edx
+ jmp *%ecx
+
+L(no_shstk):
+ /* Jump to the return PC. Don't jump directly since this
+ disturbs the branch target cache. Instead push the return
+ address back on the stack. */
+ pushl %ecx
+ cfi_adjust_cfa_offset (4)
+#endif
+
ret
PSEUDO_END (__vfork)
diff --git a/sysdeps/unix/sysv/linux/x86_64/vfork.S b/sysdeps/unix/sysv/linux/x86_64/vfork.S
index e4c8269e3d..cab3ad34a0 100644
--- a/sysdeps/unix/sysv/linux/x86_64/vfork.S
+++ b/sysdeps/unix/sysv/linux/x86_64/vfork.S
@@ -20,6 +20,18 @@
#include <bits/errno.h>
#include <tcb-offsets.h>
+#if defined __CET__ && (__CET__ & 2) != 0
+/* When shadow stack is in use, we need to pop shadow stack and jump
+ back to caller directly. */
+# undef SYSCALL_ERROR_HANDLER
+# define SYSCALL_ERROR_HANDLER \
+0: \
+ SYSCALL_SET_ERRNO; \
+ or $-1, %RAX_LP; \
+ jmp 1b;
+# undef SYSCALL_ERROR_LABEL
+# define SYSCALL_ERROR_LABEL 0f
+#endif
/* Clone the calling process, but without copying the whole address space.
The calling process is suspended until the new process exits or is
@@ -38,13 +50,36 @@ ENTRY (__vfork)
movl $SYS_ify (vfork), %eax
syscall
+#if !defined __CET__ || (__CET__ & 2) == 0
/* Push back the return PC. */
pushq %rdi
cfi_adjust_cfa_offset(8)
+#endif
cmpl $-4095, %eax
jae SYSCALL_ERROR_LABEL /* Branch forward if it failed. */
+#if defined __CET__ && (__CET__ & 2) != 0
+1:
+ /* Check if shadow stack is in use. */
+ xorl %esi, %esi
+ rdsspq %rsi
+ testq %rsi, %rsi
+ /* Normal return if shadow stack isn't in use. */
+ je L(no_shstk)
+
+ /* Pop return address from shadow stack and jump back to caller
+ directly. */
+ movl $1, %esi
+ incsspq %rsi
+ jmp *%rdi
+
+L(no_shstk):
+ /* Push back the return PC. */
+ pushq %rdi
+ cfi_adjust_cfa_offset(8)
+#endif
+
/* Normal return. */
ret
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* [PATCH 14/24] x86-64: Use _CET_NOTRACK in memcpy-ssse3.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (19 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 08/24] x86: Update vfork to pop shadow stack H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-06-13 15:32 ` [PATCH 24/24] Intel CET: Document --enable-cet H.J. Lu
` (3 subsequent siblings)
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
* sysdeps/x86_64/multiarch/memcpy-ssse3.S
(BRANCH_TO_JMPTBL_ENTRY): Add _CET_NOTRACK before indirect jump
to jump table.
(MEMCPY): Likewise.
---
sysdeps/x86_64/multiarch/memcpy-ssse3.S | 124 ++++++++++++------------
1 file changed, 62 insertions(+), 62 deletions(-)
diff --git a/sysdeps/x86_64/multiarch/memcpy-ssse3.S b/sysdeps/x86_64/multiarch/memcpy-ssse3.S
index 5dd209034b..0240bfa309 100644
--- a/sysdeps/x86_64/multiarch/memcpy-ssse3.S
+++ b/sysdeps/x86_64/multiarch/memcpy-ssse3.S
@@ -39,7 +39,7 @@
lea TABLE(%rip), %r11; \
movslq (%r11, INDEX, SCALE), INDEX; \
lea (%r11, INDEX), INDEX; \
- jmp *INDEX; \
+ _CET_NOTRACK jmp *INDEX; \
ud2
.section .text.ssse3,"ax",@progbits
@@ -86,7 +86,7 @@ L(start):
add %rdx, %rsi
add %rdx, %rdi
add %r11, %r9
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
.p2align 4
@@ -441,7 +441,7 @@ L(shl_1):
lea (L(shl_1_loop_L2)-L(shl_1_loop_L1))(%r9), %r9
L(L1_fwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_1_loop_L2):
prefetchnta 0x1c0(%rsi)
@@ -464,7 +464,7 @@ L(shl_1_loop_L1):
jb L(shl_1_end)
movaps %xmm4, -0x20(%rdi)
movaps %xmm5, -0x10(%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_1_end):
movaps %xmm4, -0x20(%rdi)
@@ -484,7 +484,7 @@ L(shl_1_bwd):
lea (L(shl_1_bwd_loop_L2)-L(shl_1_bwd_loop_L1))(%r9), %r9
L(L1_bwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_1_bwd_loop_L2):
prefetchnta -0x1c0(%rsi)
@@ -509,7 +509,7 @@ L(shl_1_bwd_loop_L1):
movaps %xmm3, 0x10(%rdi)
jb L(shl_1_bwd_end)
movaps %xmm4, (%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_1_bwd_end):
movaps %xmm4, (%rdi)
@@ -526,7 +526,7 @@ L(shl_2):
lea (L(shl_2_loop_L2)-L(shl_2_loop_L1))(%r9), %r9
L(L2_fwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_2_loop_L2):
prefetchnta 0x1c0(%rsi)
@@ -549,7 +549,7 @@ L(shl_2_loop_L1):
jb L(shl_2_end)
movaps %xmm4, -0x20(%rdi)
movaps %xmm5, -0x10(%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_2_end):
movaps %xmm4, -0x20(%rdi)
@@ -569,7 +569,7 @@ L(shl_2_bwd):
lea (L(shl_2_bwd_loop_L2)-L(shl_2_bwd_loop_L1))(%r9), %r9
L(L2_bwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_2_bwd_loop_L2):
prefetchnta -0x1c0(%rsi)
@@ -594,7 +594,7 @@ L(shl_2_bwd_loop_L1):
movaps %xmm3, 0x10(%rdi)
jb L(shl_2_bwd_end)
movaps %xmm4, (%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_2_bwd_end):
movaps %xmm4, (%rdi)
@@ -611,7 +611,7 @@ L(shl_3):
lea (L(shl_3_loop_L2)-L(shl_3_loop_L1))(%r9), %r9
L(L3_fwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_3_loop_L2):
prefetchnta 0x1c0(%rsi)
@@ -634,7 +634,7 @@ L(shl_3_loop_L1):
jb L(shl_3_end)
movaps %xmm4, -0x20(%rdi)
movaps %xmm5, -0x10(%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_3_end):
movaps %xmm4, -0x20(%rdi)
@@ -654,7 +654,7 @@ L(shl_3_bwd):
lea (L(shl_3_bwd_loop_L2)-L(shl_3_bwd_loop_L1))(%r9), %r9
L(L3_bwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_3_bwd_loop_L2):
prefetchnta -0x1c0(%rsi)
@@ -679,7 +679,7 @@ L(shl_3_bwd_loop_L1):
movaps %xmm3, 0x10(%rdi)
jb L(shl_3_bwd_end)
movaps %xmm4, (%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_3_bwd_end):
movaps %xmm4, (%rdi)
@@ -696,7 +696,7 @@ L(shl_4):
lea (L(shl_4_loop_L2)-L(shl_4_loop_L1))(%r9), %r9
L(L4_fwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_4_loop_L2):
prefetchnta 0x1c0(%rsi)
@@ -719,7 +719,7 @@ L(shl_4_loop_L1):
jb L(shl_4_end)
movaps %xmm4, -0x20(%rdi)
movaps %xmm5, -0x10(%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_4_end):
movaps %xmm4, -0x20(%rdi)
@@ -739,7 +739,7 @@ L(shl_4_bwd):
lea (L(shl_4_bwd_loop_L2)-L(shl_4_bwd_loop_L1))(%r9), %r9
L(L4_bwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_4_bwd_loop_L2):
prefetchnta -0x1c0(%rsi)
@@ -764,7 +764,7 @@ L(shl_4_bwd_loop_L1):
movaps %xmm3, 0x10(%rdi)
jb L(shl_4_bwd_end)
movaps %xmm4, (%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_4_bwd_end):
movaps %xmm4, (%rdi)
@@ -781,7 +781,7 @@ L(shl_5):
lea (L(shl_5_loop_L2)-L(shl_5_loop_L1))(%r9), %r9
L(L5_fwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_5_loop_L2):
prefetchnta 0x1c0(%rsi)
@@ -804,7 +804,7 @@ L(shl_5_loop_L1):
jb L(shl_5_end)
movaps %xmm4, -0x20(%rdi)
movaps %xmm5, -0x10(%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_5_end):
movaps %xmm4, -0x20(%rdi)
@@ -824,7 +824,7 @@ L(shl_5_bwd):
lea (L(shl_5_bwd_loop_L2)-L(shl_5_bwd_loop_L1))(%r9), %r9
L(L5_bwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_5_bwd_loop_L2):
prefetchnta -0x1c0(%rsi)
@@ -849,7 +849,7 @@ L(shl_5_bwd_loop_L1):
movaps %xmm3, 0x10(%rdi)
jb L(shl_5_bwd_end)
movaps %xmm4, (%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_5_bwd_end):
movaps %xmm4, (%rdi)
@@ -866,7 +866,7 @@ L(shl_6):
lea (L(shl_6_loop_L2)-L(shl_6_loop_L1))(%r9), %r9
L(L6_fwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_6_loop_L2):
prefetchnta 0x1c0(%rsi)
@@ -889,7 +889,7 @@ L(shl_6_loop_L1):
jb L(shl_6_end)
movaps %xmm4, -0x20(%rdi)
movaps %xmm5, -0x10(%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_6_end):
movaps %xmm4, -0x20(%rdi)
@@ -909,7 +909,7 @@ L(shl_6_bwd):
lea (L(shl_6_bwd_loop_L2)-L(shl_6_bwd_loop_L1))(%r9), %r9
L(L6_bwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_6_bwd_loop_L2):
prefetchnta -0x1c0(%rsi)
@@ -934,7 +934,7 @@ L(shl_6_bwd_loop_L1):
movaps %xmm3, 0x10(%rdi)
jb L(shl_6_bwd_end)
movaps %xmm4, (%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_6_bwd_end):
movaps %xmm4, (%rdi)
@@ -951,7 +951,7 @@ L(shl_7):
lea (L(shl_7_loop_L2)-L(shl_7_loop_L1))(%r9), %r9
L(L7_fwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_7_loop_L2):
prefetchnta 0x1c0(%rsi)
@@ -974,7 +974,7 @@ L(shl_7_loop_L1):
jb L(shl_7_end)
movaps %xmm4, -0x20(%rdi)
movaps %xmm5, -0x10(%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_7_end):
movaps %xmm4, -0x20(%rdi)
@@ -994,7 +994,7 @@ L(shl_7_bwd):
lea (L(shl_7_bwd_loop_L2)-L(shl_7_bwd_loop_L1))(%r9), %r9
L(L7_bwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_7_bwd_loop_L2):
prefetchnta -0x1c0(%rsi)
@@ -1019,7 +1019,7 @@ L(shl_7_bwd_loop_L1):
movaps %xmm3, 0x10(%rdi)
jb L(shl_7_bwd_end)
movaps %xmm4, (%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_7_bwd_end):
movaps %xmm4, (%rdi)
@@ -1036,7 +1036,7 @@ L(shl_8):
lea (L(shl_8_loop_L2)-L(shl_8_loop_L1))(%r9), %r9
L(L8_fwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
L(shl_8_loop_L2):
prefetchnta 0x1c0(%rsi)
L(shl_8_loop_L1):
@@ -1058,7 +1058,7 @@ L(shl_8_loop_L1):
jb L(shl_8_end)
movaps %xmm4, -0x20(%rdi)
movaps %xmm5, -0x10(%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
.p2align 4
L(shl_8_end):
@@ -1079,7 +1079,7 @@ L(shl_8_bwd):
lea (L(shl_8_bwd_loop_L2)-L(shl_8_bwd_loop_L1))(%r9), %r9
L(L8_bwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_8_bwd_loop_L2):
prefetchnta -0x1c0(%rsi)
@@ -1104,7 +1104,7 @@ L(shl_8_bwd_loop_L1):
movaps %xmm3, 0x10(%rdi)
jb L(shl_8_bwd_end)
movaps %xmm4, (%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_8_bwd_end):
movaps %xmm4, (%rdi)
@@ -1121,7 +1121,7 @@ L(shl_9):
lea (L(shl_9_loop_L2)-L(shl_9_loop_L1))(%r9), %r9
L(L9_fwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_9_loop_L2):
prefetchnta 0x1c0(%rsi)
@@ -1144,7 +1144,7 @@ L(shl_9_loop_L1):
jb L(shl_9_end)
movaps %xmm4, -0x20(%rdi)
movaps %xmm5, -0x10(%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_9_end):
movaps %xmm4, -0x20(%rdi)
@@ -1164,7 +1164,7 @@ L(shl_9_bwd):
lea (L(shl_9_bwd_loop_L2)-L(shl_9_bwd_loop_L1))(%r9), %r9
L(L9_bwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_9_bwd_loop_L2):
prefetchnta -0x1c0(%rsi)
@@ -1189,7 +1189,7 @@ L(shl_9_bwd_loop_L1):
movaps %xmm3, 0x10(%rdi)
jb L(shl_9_bwd_end)
movaps %xmm4, (%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_9_bwd_end):
movaps %xmm4, (%rdi)
@@ -1206,7 +1206,7 @@ L(shl_10):
lea (L(shl_10_loop_L2)-L(shl_10_loop_L1))(%r9), %r9
L(L10_fwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_10_loop_L2):
prefetchnta 0x1c0(%rsi)
@@ -1229,7 +1229,7 @@ L(shl_10_loop_L1):
jb L(shl_10_end)
movaps %xmm4, -0x20(%rdi)
movaps %xmm5, -0x10(%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_10_end):
movaps %xmm4, -0x20(%rdi)
@@ -1249,7 +1249,7 @@ L(shl_10_bwd):
lea (L(shl_10_bwd_loop_L2)-L(shl_10_bwd_loop_L1))(%r9), %r9
L(L10_bwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_10_bwd_loop_L2):
prefetchnta -0x1c0(%rsi)
@@ -1274,7 +1274,7 @@ L(shl_10_bwd_loop_L1):
movaps %xmm3, 0x10(%rdi)
jb L(shl_10_bwd_end)
movaps %xmm4, (%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_10_bwd_end):
movaps %xmm4, (%rdi)
@@ -1291,7 +1291,7 @@ L(shl_11):
lea (L(shl_11_loop_L2)-L(shl_11_loop_L1))(%r9), %r9
L(L11_fwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_11_loop_L2):
prefetchnta 0x1c0(%rsi)
@@ -1314,7 +1314,7 @@ L(shl_11_loop_L1):
jb L(shl_11_end)
movaps %xmm4, -0x20(%rdi)
movaps %xmm5, -0x10(%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_11_end):
movaps %xmm4, -0x20(%rdi)
@@ -1334,7 +1334,7 @@ L(shl_11_bwd):
lea (L(shl_11_bwd_loop_L2)-L(shl_11_bwd_loop_L1))(%r9), %r9
L(L11_bwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_11_bwd_loop_L2):
prefetchnta -0x1c0(%rsi)
@@ -1359,7 +1359,7 @@ L(shl_11_bwd_loop_L1):
movaps %xmm3, 0x10(%rdi)
jb L(shl_11_bwd_end)
movaps %xmm4, (%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_11_bwd_end):
movaps %xmm4, (%rdi)
@@ -1376,7 +1376,7 @@ L(shl_12):
lea (L(shl_12_loop_L2)-L(shl_12_loop_L1))(%r9), %r9
L(L12_fwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_12_loop_L2):
prefetchnta 0x1c0(%rsi)
@@ -1399,7 +1399,7 @@ L(shl_12_loop_L1):
jb L(shl_12_end)
movaps %xmm4, -0x20(%rdi)
movaps %xmm5, -0x10(%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_12_end):
movaps %xmm4, -0x20(%rdi)
@@ -1419,7 +1419,7 @@ L(shl_12_bwd):
lea (L(shl_12_bwd_loop_L2)-L(shl_12_bwd_loop_L1))(%r9), %r9
L(L12_bwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_12_bwd_loop_L2):
prefetchnta -0x1c0(%rsi)
@@ -1444,7 +1444,7 @@ L(shl_12_bwd_loop_L1):
movaps %xmm3, 0x10(%rdi)
jb L(shl_12_bwd_end)
movaps %xmm4, (%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_12_bwd_end):
movaps %xmm4, (%rdi)
@@ -1461,7 +1461,7 @@ L(shl_13):
lea (L(shl_13_loop_L2)-L(shl_13_loop_L1))(%r9), %r9
L(L13_fwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_13_loop_L2):
prefetchnta 0x1c0(%rsi)
@@ -1484,7 +1484,7 @@ L(shl_13_loop_L1):
jb L(shl_13_end)
movaps %xmm4, -0x20(%rdi)
movaps %xmm5, -0x10(%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_13_end):
movaps %xmm4, -0x20(%rdi)
@@ -1504,7 +1504,7 @@ L(shl_13_bwd):
lea (L(shl_13_bwd_loop_L2)-L(shl_13_bwd_loop_L1))(%r9), %r9
L(L13_bwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_13_bwd_loop_L2):
prefetchnta -0x1c0(%rsi)
@@ -1529,7 +1529,7 @@ L(shl_13_bwd_loop_L1):
movaps %xmm3, 0x10(%rdi)
jb L(shl_13_bwd_end)
movaps %xmm4, (%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_13_bwd_end):
movaps %xmm4, (%rdi)
@@ -1546,7 +1546,7 @@ L(shl_14):
lea (L(shl_14_loop_L2)-L(shl_14_loop_L1))(%r9), %r9
L(L14_fwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_14_loop_L2):
prefetchnta 0x1c0(%rsi)
@@ -1569,7 +1569,7 @@ L(shl_14_loop_L1):
jb L(shl_14_end)
movaps %xmm4, -0x20(%rdi)
movaps %xmm5, -0x10(%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_14_end):
movaps %xmm4, -0x20(%rdi)
@@ -1589,7 +1589,7 @@ L(shl_14_bwd):
lea (L(shl_14_bwd_loop_L2)-L(shl_14_bwd_loop_L1))(%r9), %r9
L(L14_bwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_14_bwd_loop_L2):
prefetchnta -0x1c0(%rsi)
@@ -1614,7 +1614,7 @@ L(shl_14_bwd_loop_L1):
movaps %xmm3, 0x10(%rdi)
jb L(shl_14_bwd_end)
movaps %xmm4, (%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_14_bwd_end):
movaps %xmm4, (%rdi)
@@ -1631,7 +1631,7 @@ L(shl_15):
lea (L(shl_15_loop_L2)-L(shl_15_loop_L1))(%r9), %r9
L(L15_fwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_15_loop_L2):
prefetchnta 0x1c0(%rsi)
@@ -1654,7 +1654,7 @@ L(shl_15_loop_L1):
jb L(shl_15_end)
movaps %xmm4, -0x20(%rdi)
movaps %xmm5, -0x10(%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_15_end):
movaps %xmm4, -0x20(%rdi)
@@ -1674,7 +1674,7 @@ L(shl_15_bwd):
lea (L(shl_15_bwd_loop_L2)-L(shl_15_bwd_loop_L1))(%r9), %r9
L(L15_bwd):
lea -64(%rdx), %rdx
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_15_bwd_loop_L2):
prefetchnta -0x1c0(%rsi)
@@ -1699,7 +1699,7 @@ L(shl_15_bwd_loop_L1):
movaps %xmm3, 0x10(%rdi)
jb L(shl_15_bwd_end)
movaps %xmm4, (%rdi)
- jmp *%r9
+ _CET_NOTRACK jmp *%r9
ud2
L(shl_15_bwd_end):
movaps %xmm4, (%rdi)
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* [PATCH 24/24] Intel CET: Document --enable-cet
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (20 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 14/24] x86-64: Use _CET_NOTRACK in memcpy-ssse3.S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-06-13 15:32 ` [PATCH 22/24] i386: Use _CET_NOTRACK in memset-sse2-rep.S H.J. Lu
` (2 subsequent siblings)
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
* NEWS: Mention --enable-cet.
* manual/install.texi: Document --enable-cet.
* INSTALL: Regenerated.
---
INSTALL | 11 +++++++++++
NEWS | 10 ++++++++++
manual/install.texi | 10 ++++++++++
3 files changed, 31 insertions(+)
diff --git a/INSTALL b/INSTALL
index 052b1b6f89..5e6d80480b 100644
--- a/INSTALL
+++ b/INSTALL
@@ -106,6 +106,17 @@ if 'CFLAGS' is specified it must enable optimization. For example:
programs and tests are created as dynamic position independent
executables (PIE) by default.
+'--enable-cet'
+ Enable Intel Control-flow Enforcement Technology (CET) support.
+ When the library is built with -enable-cet, the resulting glibc is
+ protected with indirect branch tracking (IBT) and shadow stack
+ (SHSTK). CET-enabled glibc is compatible with all existing
+ executables and shared libraries. This feature is currently
+ supported on i386, x86_64 and x32 with GCC 8 and binutils 2.29 or
+ later. Note that CET-enabled glibc requires CPUs capable of
+ multi-byte NOPs, like x86-64 processors as well as Intel Pentium
+ Pro or newer.
+
'--disable-profile'
Don't build libraries with profiling information. You may want to
use this option if you don't plan to do profiling.
diff --git a/NEWS b/NEWS
index d51fa09544..e914336557 100644
--- a/NEWS
+++ b/NEWS
@@ -9,6 +9,16 @@ Version 2.28
Major new features:
+* The GNU C Library can now be compiled with support for Intel CET, AKA
+ Intel Control-flow Enforcement Technology. When the library is built
+ with --enable-cet, the resulting glibc is protected with indirect
+ branch tracking (IBT) and shadow stack (SHSTK). CET-enabled glibc is
+ compatible with all existing executables and shared libraries. This
+ feature is currently supported on i386, x86_64 and x32 with GCC 8 and
+ binutils 2.29 or later. Note that CET-enabled glibc requires CPUs
+ capable of multi-byte NOPs, like x86-64 processors as well as Intel
+ Pentium Pro or newer.
+
* <math.h> functions that round their results to a narrower type are added
from TS 18661-1:2014 and TS 18661-3:2015:
diff --git a/manual/install.texi b/manual/install.texi
index 4bbbfcffa5..62aec719d7 100644
--- a/manual/install.texi
+++ b/manual/install.texi
@@ -137,6 +137,16 @@ with no-pie. The resulting glibc can be used with the GCC option,
PIE. This option also implies that glibc programs and tests are created
as dynamic position independent executables (PIE) by default.
+@item --enable-cet
+Enable Intel Control-flow Enforcement Technology (CET) support. When
+the library is built with --enable-cet, the resulting glibc is protected
+with indirect branch tracking (IBT) and shadow stack (SHSTK)@. CET-enabled
+glibc is compatible with all existing executables and shared libraries.
+This feature is currently supported on i386, x86_64 and x32 with GCC 8 and
+binutils 2.29 or later. Note that CET-enabled glibc requires CPUs capable
+of multi-byte NOPs, like x86-64 processors as well as Intel Pentium Pro or
+newer.
+
@item --disable-profile
Don't build libraries with profiling information. You may want to use
this option if you don't plan to do profiling.
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* [PATCH 22/24] i386: Use _CET_NOTRACK in memset-sse2-rep.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (21 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 24/24] Intel CET: Document --enable-cet H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-06-13 15:32 ` [PATCH 09/24] x86_64: Use _CET_NOTRACK in strcmp.S H.J. Lu
2018-07-02 14:54 ` [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
* sysdeps/i386/i686/multiarch/memset-sse2-rep.S
(BRANCH_TO_JMPTBL_ENTRY): Add _CET_NOTRACK before indirect jump
to jump table.
---
sysdeps/i386/i686/multiarch/memset-sse2-rep.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/sysdeps/i386/i686/multiarch/memset-sse2-rep.S b/sysdeps/i386/i686/multiarch/memset-sse2-rep.S
index 9d6648b5ce..8732aac0b9 100644
--- a/sysdeps/i386/i686/multiarch/memset-sse2-rep.S
+++ b/sysdeps/i386/i686/multiarch/memset-sse2-rep.S
@@ -63,7 +63,7 @@
add (%ebx,%ecx,4), %ebx; \
add %ecx, %edx; \
/* We loaded the jump table and adjusted EDX. Go. */ \
- jmp *%ebx
+ _CET_NOTRACK jmp *%ebx
#else
# define ENTRANCE
# define RETURN_END ret
@@ -75,7 +75,7 @@
absolute offsets. */
# define BRANCH_TO_JMPTBL_ENTRY(TABLE) \
add %ecx, %edx; \
- jmp *TABLE(,%ecx,4)
+ _CET_NOTRACK jmp *TABLE(,%ecx,4)
#endif
.section .text.sse2,"ax",@progbits
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* [PATCH 09/24] x86_64: Use _CET_NOTRACK in strcmp.S
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (22 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 22/24] i386: Use _CET_NOTRACK in memset-sse2-rep.S H.J. Lu
@ 2018-06-13 15:32 ` H.J. Lu
2018-07-18 3:17 ` H.J. Lu
2018-07-02 14:54 ` [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
24 siblings, 1 reply; 54+ messages in thread
From: H.J. Lu @ 2018-06-13 15:32 UTC (permalink / raw)
To: libc-alpha
* sysdeps/x86_64/strcmp.S (STRCMP): Add _CET_NOTRACK before
indirect jump to jump table.
---
sysdeps/x86_64/strcmp.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sysdeps/x86_64/strcmp.S b/sysdeps/x86_64/strcmp.S
index de54fce647..e16945b961 100644
--- a/sysdeps/x86_64/strcmp.S
+++ b/sysdeps/x86_64/strcmp.S
@@ -233,7 +233,7 @@ LABEL(bigger):
lea LABEL(unaligned_table)(%rip), %r10
movslq (%r10, %r9,4), %r9
lea (%r10, %r9), %r10
- jmp *%r10 /* jump to corresponding case */
+ _CET_NOTRACK jmp *%r10 /* jump to corresponding case */
/*
* The following cases will be handled by ashr_0
--
2.17.1
^ permalink raw reply [flat|nested] 54+ messages in thread* Re: [PATCH 09/24] x86_64: Use _CET_NOTRACK in strcmp.S
2018-06-13 15:32 ` [PATCH 09/24] x86_64: Use _CET_NOTRACK in strcmp.S H.J. Lu
@ 2018-07-18 3:17 ` H.J. Lu
0 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-07-18 3:17 UTC (permalink / raw)
To: GNU C Library, Carlos O'Donell
On Wed, Jun 13, 2018 at 8:31 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> * sysdeps/x86_64/strcmp.S (STRCMP): Add _CET_NOTRACK before
> indirect jump to jump table.
> ---
> sysdeps/x86_64/strcmp.S | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/sysdeps/x86_64/strcmp.S b/sysdeps/x86_64/strcmp.S
> index de54fce647..e16945b961 100644
> --- a/sysdeps/x86_64/strcmp.S
> +++ b/sysdeps/x86_64/strcmp.S
> @@ -233,7 +233,7 @@ LABEL(bigger):
> lea LABEL(unaligned_table)(%rip), %r10
> movslq (%r10, %r9,4), %r9
> lea (%r10, %r9), %r10
> - jmp *%r10 /* jump to corresponding case */
> + _CET_NOTRACK jmp *%r10 /* jump to corresponding case */
>
> /*
> * The following cases will be handled by ashr_0
> --
> 2.17.1
>
I am going to check in the rest of _CET_NOTRACK patches:
https://sourceware.org/ml/libc-alpha/2018-06/msg00322.html
https://sourceware.org/ml/libc-alpha/2018-06/msg00342.html
https://sourceware.org/ml/libc-alpha/2018-06/msg00335.html
https://sourceware.org/ml/libc-alpha/2018-06/msg00334.html
https://sourceware.org/ml/libc-alpha/2018-06/msg00332.html
https://sourceware.org/ml/libc-alpha/2018-06/msg00326.html
https://sourceware.org/ml/libc-alpha/2018-06/msg00331.html
https://sourceware.org/ml/libc-alpha/2018-06/msg00338.html
https://sourceware.org/ml/libc-alpha/2018-06/msg00330.html
https://sourceware.org/ml/libc-alpha/2018-06/msg00340.html
https://sourceware.org/ml/libc-alpha/2018-06/msg00339.html
https://sourceware.org/ml/libc-alpha/2018-06/msg00343.html
https://sourceware.org/ml/libc-alpha/2018-06/msg00336.html
--
H.J.
^ permalink raw reply [flat|nested] 54+ messages in thread
* Re: [PATCH-V2: 00/24] CET: Prepare for CET enabling
2018-06-13 15:32 [PATCH-V2: 00/24] CET: Prepare for CET enabling H.J. Lu
` (23 preceding siblings ...)
2018-06-13 15:32 ` [PATCH 09/24] x86_64: Use _CET_NOTRACK in strcmp.S H.J. Lu
@ 2018-07-02 14:54 ` H.J. Lu
24 siblings, 0 replies; 54+ messages in thread
From: H.J. Lu @ 2018-07-02 14:54 UTC (permalink / raw)
To: GNU C Library
On Wed, Jun 13, 2018 at 8:31 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> This is the first set of patches to enable CET, excluding changes which
> use the new CET system calls. The complete set of patches is available
> on hjl/cet/master branch at:
>
> https://github.com/hjl-tools/glibc/tree/hjl/cet/master
>
> I will submit the second set of patches with the new CET system calls,
> which are on Linux kernel CET branch:
>
> https://github.com/yyu168/linux_cet
>
> later.
>
>
> H.J. Lu (24):
> x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563]
> x86: Support shadow stack pointer in setjmp/longjmp
> x86: Support IBT and SHSTK in Intel CET [BZ #21598]
> x86: Add _CET_ENDBR to functions in crti.S
> x86: Add _CET_ENDBR to functions in dl-tlsdesc.S
> x86-64: Add _CET_ENDBR to STRCMP_SSE42
> i386: Add _CET_ENDBR to indirect jump targets in add_n.S/sub_n.S
> x86: Update vfork to pop shadow stack
> x86_64: Use _CET_NOTRACK in strcmp.S
> x86-64: Use _CET_NOTRACK in strcpy-sse2-unaligned.S
> x86-64: Use _CET_NOTRACK in strcmp-sse42.S
> x86-64: Use _CET_NOTRACK in memcpy-ssse3-back.S
> x86-64: Use _CET_NOTRACK in memcmp-sse4.S
> x86-64: Use _CET_NOTRACK in memcpy-ssse3.S
> i386: Use _CET_NOTRACK in i686/memcmp.S
> i386: Use _CET_NOTRACK in memset-sse2.S
> i386: Use _CET_NOTRACK in memcmp-sse4.S
> i386: Use _CET_NOTRACK in memcpy-ssse3-rep.S
> i386: Use _CET_NOTRACK in memcpy-ssse3.S
> i386: Use _CET_NOTRACK in strcpy-sse2.S
> i386: Use _CET_NOTRACK in strcat-sse2.S
> i386: Use _CET_NOTRACK in memset-sse2-rep.S
> x86-64: Add endbr64 to tst-quadmod[12].S
> Intel CET: Document --enable-cet
>
> INSTALL | 11 ++
> NEWS | 10 +
> configure | 11 ++
> configure.ac | 6 +
> elf/dl-load.c | 61 +++---
> elf/dl-open.c | 4 +
> elf/rtld.c | 12 ++
> manual/install.texi | 10 +
> nptl/pthread_create.c | 5 +
> sysdeps/i386/__longjmp.S | 78 ++++++++
> sysdeps/i386/add_n.S | 27 ++-
> sysdeps/i386/bsd-_setjmp.S | 21 ++
> sysdeps/i386/bsd-setjmp.S | 21 ++
> sysdeps/i386/crti.S | 2 +
> sysdeps/i386/dl-tlsdesc.S | 7 +
> sysdeps/i386/dl-trampoline.S | 72 +++++++
> sysdeps/i386/i686/add_n.S | 27 ++-
> sysdeps/i386/i686/memcmp.S | 4 +-
> sysdeps/i386/i686/multiarch/memcmp-sse4.S | 4 +-
> .../i386/i686/multiarch/memcpy-ssse3-rep.S | 8 +-
> sysdeps/i386/i686/multiarch/memcpy-ssse3.S | 4 +-
> sysdeps/i386/i686/multiarch/memset-sse2-rep.S | 4 +-
> sysdeps/i386/i686/multiarch/memset-sse2.S | 4 +-
> sysdeps/i386/i686/multiarch/strcat-sse2.S | 4 +-
> sysdeps/i386/i686/multiarch/strcpy-sse2.S | 4 +-
> sysdeps/i386/nptl/tcb-offsets.sym | 1 +
> sysdeps/i386/nptl/tls.h | 5 +-
> sysdeps/i386/setjmp.S | 21 ++
> sysdeps/i386/sub_n.S | 26 ++-
> .../unix/sysv/linux/i386/____longjmp_chk.S | 40 ++++
> sysdeps/unix/sysv/linux/i386/dl-cet.c | 67 +++++++
> sysdeps/unix/sysv/linux/i386/dl-machine.h | 23 +++
> sysdeps/unix/sysv/linux/i386/vfork.S | 54 +++++
> sysdeps/unix/sysv/linux/x86/Makefile | 43 +++-
> sysdeps/unix/sysv/linux/x86/check-cet.awk | 53 +++++
> sysdeps/unix/sysv/linux/x86/configure | 69 +++++++
> sysdeps/unix/sysv/linux/x86/configure.ac | 46 +++++
> sysdeps/unix/sysv/linux/x86/dl-cet.c | 186 ++++++++++++++++++
> sysdeps/unix/sysv/linux/x86/dl-cet.h | 138 +++++++++++++
> sysdeps/unix/sysv/linux/x86/dl-procruntime.c | 57 ++++++
> sysdeps/unix/sysv/linux/x86/ldsodefs.h | 29 +++
> sysdeps/unix/sysv/linux/x86/link_map.h | 26 +++
> sysdeps/unix/sysv/linux/x86/pthreaddef.h | 24 +++
> .../unix/sysv/linux/x86_64/____longjmp_chk.S | 41 ++++
> sysdeps/unix/sysv/linux/x86_64/dl-machine.h | 27 +++
> sysdeps/unix/sysv/linux/x86_64/vfork.S | 35 ++++
> sysdeps/x86/Makefile | 1 +
> sysdeps/x86/cpu-features.h | 5 +
> sysdeps/x86/jmp_buf-ssp.sym | 1 +
> sysdeps/x86/sysdep.h | 8 +
> sysdeps/x86_64/__longjmp.S | 45 +++++
> sysdeps/x86_64/crti.S | 2 +
> sysdeps/x86_64/dl-tlsdesc.S | 5 +
> sysdeps/x86_64/dl-trampoline.h | 2 +
> sysdeps/x86_64/multiarch/memcmp-sse4.S | 2 +-
> sysdeps/x86_64/multiarch/memcpy-ssse3-back.S | 6 +-
> sysdeps/x86_64/multiarch/memcpy-ssse3.S | 124 ++++++------
> sysdeps/x86_64/multiarch/strcmp-sse42.S | 3 +-
> .../x86_64/multiarch/strcpy-sse2-unaligned.S | 2 +-
> sysdeps/x86_64/nptl/tcb-offsets.sym | 1 +
> sysdeps/x86_64/nptl/tls.h | 5 +-
> sysdeps/x86_64/setjmp.S | 21 ++
> sysdeps/x86_64/strcmp.S | 2 +-
> sysdeps/x86_64/tst-quadmod1.S | 6 +
> sysdeps/x86_64/tst-quadmod2.S | 6 +
> 65 files changed, 1561 insertions(+), 118 deletions(-)
> create mode 100644 sysdeps/unix/sysv/linux/i386/dl-cet.c
> create mode 100644 sysdeps/unix/sysv/linux/i386/dl-machine.h
> create mode 100644 sysdeps/unix/sysv/linux/x86/check-cet.awk
> create mode 100644 sysdeps/unix/sysv/linux/x86/configure
> create mode 100644 sysdeps/unix/sysv/linux/x86/configure.ac
> create mode 100644 sysdeps/unix/sysv/linux/x86/dl-cet.c
> create mode 100644 sysdeps/unix/sysv/linux/x86/dl-cet.h
> create mode 100644 sysdeps/unix/sysv/linux/x86/dl-procruntime.c
> create mode 100644 sysdeps/unix/sysv/linux/x86/ldsodefs.h
> create mode 100644 sysdeps/unix/sysv/linux/x86/link_map.h
> create mode 100644 sysdeps/unix/sysv/linux/x86/pthreaddef.h
> create mode 100644 sysdeps/unix/sysv/linux/x86_64/dl-machine.h
> create mode 100644 sysdeps/x86/jmp_buf-ssp.sym
>
> --
> 2.17.1
>
PING.
--
H.J.
^ permalink raw reply [flat|nested] 54+ messages in thread