* [PATCH v2 0/2] Improve -z mark-plt
@ 2024-01-06 22:09 H.J. Lu
2024-01-06 22:10 ` [PATCH v2 1/2] elf: Add elf_backend_add_glibc_version_dependency H.J. Lu
2024-01-06 22:10 ` [PATCH v2 2/2] ld: Add --enable-mark-plt configure option H.J. Lu
0 siblings, 2 replies; 7+ messages in thread
From: H.J. Lu @ 2024-01-06 22:09 UTC (permalink / raw)
To: binutils
Changes in v2:
1. Fix typos. It should be --enable-mark-plt, not --enable-make-plt.
2. Remove tests changes for -z mark-plt.
Add --enable-mark-plt linker configure option to mark PLT entries with
DT_X86_64_PLT, DT_X86_64_PLTSZ and DT_X86_64_PLTENT dynamic tags by
default.
When -z mark-plt is used to add DT_X86_64_PLT, DT_X86_64_PLTSZ and
DT_X86_64_PLTENT, the r_addend field of the R_X86_64_JUMP_SLOT relocation
stores the offset of the indirect branch instruction. However, glibc
versions which don't have this commit in glibc 2.36:
commit f8587a61892cbafd98ce599131bf4f103466f084
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Fri May 20 19:21:48 2022 -0700
x86-64: Ignore r_addend for R_X86_64_GLOB_DAT/R_X86_64_JUMP_SLOT
According to x86-64 psABI, r_addend should be ignored for R_X86_64_GLOB_DAT
and R_X86_64_JUMP_SLOT. Since linkers always set their r_addends to 0, we
can ignore their r_addends.
Reviewed-by: Fangrui Song <maskray@google.com>
won't ignore the r_addend value in the R_X86_64_JUMP_SLOT relocation.
Although this commit has been backported to glibc 2.33/2.34/2.35 release
branches, it is safer to require glibc 2.36 for such binaries.
Extend the glibc version dependency of GLIBC_ABI_DT_RELR for DT_RELR to
also add GLIBC_2.36 version dependency for -z mark-plt on the the shared C
library if it provides a GLIBC_2.XX symbol version.
H.J. Lu (2):
elf: Add elf_backend_add_glibc_version_dependency
ld: Add --enable-mark-plt configure option
bfd/elf-bfd.h | 23 ++++
bfd/elf64-x86-64.c | 27 +++++
bfd/elflink.c | 146 +++++++++++++++-----------
bfd/elfxx-target.h | 5 +
ld/NEWS | 5 +
ld/config.in | 4 +
ld/configure | 26 ++++-
ld/configure.ac | 17 +++
ld/emulparams/x86-64-plt.sh | 7 +-
ld/emultempl/elf-x86.em | 17 +++
ld/testsuite/ld-x86-64/mark-plt-1a.rd | 7 ++
ld/testsuite/ld-x86-64/mark-plt-1b.rd | 7 ++
ld/testsuite/ld-x86-64/x86-64.exp | 14 +++
13 files changed, 240 insertions(+), 65 deletions(-)
create mode 100644 ld/testsuite/ld-x86-64/mark-plt-1a.rd
create mode 100644 ld/testsuite/ld-x86-64/mark-plt-1b.rd
--
2.43.0
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v2 1/2] elf: Add elf_backend_add_glibc_version_dependency
2024-01-06 22:09 [PATCH v2 0/2] Improve -z mark-plt H.J. Lu
@ 2024-01-06 22:10 ` H.J. Lu
2024-01-08 15:22 ` H.J. Lu
2024-01-06 22:10 ` [PATCH v2 2/2] ld: Add --enable-mark-plt configure option H.J. Lu
1 sibling, 1 reply; 7+ messages in thread
From: H.J. Lu @ 2024-01-06 22:10 UTC (permalink / raw)
To: binutils
When -z mark-plt is used to add DT_X86_64_PLT, DT_X86_64_PLTSZ and
DT_X86_64_PLTENT, the r_addend field of the R_X86_64_JUMP_SLOT relocation
stores the offset of the indirect branch instruction. However, glibc
versions which don't have this commit in glibc 2.36:
commit f8587a61892cbafd98ce599131bf4f103466f084
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Fri May 20 19:21:48 2022 -0700
x86-64: Ignore r_addend for R_X86_64_GLOB_DAT/R_X86_64_JUMP_SLOT
According to x86-64 psABI, r_addend should be ignored for R_X86_64_GLOB_DAT
and R_X86_64_JUMP_SLOT. Since linkers always set their r_addends to 0, we
can ignore their r_addends.
Reviewed-by: Fangrui Song <maskray@google.com>
won't ignore the r_addend value in the R_X86_64_JUMP_SLOT relocation.
Although this commit has been backported to glibc 2.33/2.34/2.35 release
branches, it is safer to require glibc 2.36 for such binaries.
Extend the glibc version dependency of GLIBC_ABI_DT_RELR for DT_RELR to
also add GLIBC_2.36 version dependency for -z mark-plt on the the shared C
library if it provides a GLIBC_2.XX symbol version.
* elflink.c (elf_find_verdep_info): Moved to ...
* elf-bfd.h (elf_find_verdep_info): Here.
(elf_backend_data): Add elf_backend_add_glibc_version_dependency.
(_bfd_elf_link_add_glibc_version_dependency): New function.
(_bfd_elf_link_add_dt_relr_dependency): Likewise.
* elf64-x86-64.c (elf_x86_64_add_glibc_version_dependency):
Likewise.
(elf_backend_add_glibc_version_dependency): New.
* elflink.c (elf_link_add_dt_relr_dependency): Renamed to ...
(elf_link_add_glibc_verneed): This. Modified to support other
glibc dependencies.
(_bfd_elf_link_add_glibc_version_dependency): Likewise.
(_bfd_elf_link_add_dt_relr_dependency): Likewise.
(bfd_elf_size_dynamic_sections): Call
elf_backend_add_glibc_version_dependency instead of
elf_link_add_dt_relr_dependency.
* elfxx-target.h (elf_backend_add_glibc_version_dependency): New.
(elfNN_bed): Add elf_backend_add_glibc_version_dependency.
ld/
* testsuite/ld-x86-64/mark-plt-1a.rd: New file.
* testsuite/ld-x86-64/mark-plt-1b.rd: Likewise.
* testsuite/ld-x86-64/x86-64.exp: Run -z mark-plt test for
GLIBC_2.36 dependency.
---
bfd/elf-bfd.h | 23 ++++
bfd/elf64-x86-64.c | 27 +++++
bfd/elflink.c | 146 +++++++++++++++-----------
bfd/elfxx-target.h | 5 +
ld/testsuite/ld-x86-64/mark-plt-1a.rd | 7 ++
ld/testsuite/ld-x86-64/mark-plt-1b.rd | 7 ++
ld/testsuite/ld-x86-64/x86-64.exp | 14 +++
7 files changed, 167 insertions(+), 62 deletions(-)
create mode 100644 ld/testsuite/ld-x86-64/mark-plt-1a.rd
create mode 100644 ld/testsuite/ld-x86-64/mark-plt-1b.rd
diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
index a611349e3d9..3ed22fa6c52 100644
--- a/bfd/elf-bfd.h
+++ b/bfd/elf-bfd.h
@@ -957,6 +957,19 @@ typedef struct elf_property_list
struct elf_property property;
} elf_property_list;
+/* This structure is used to pass information to
+ elf_backend_add_glibc_version_dependency. */
+
+struct elf_find_verdep_info
+{
+ /* General link information. */
+ struct bfd_link_info *info;
+ /* The number of dependencies. */
+ unsigned int vers;
+ /* Whether we had a failure. */
+ bool failed;
+};
+
struct bfd_elf_section_reloc_data;
struct elf_backend_data
@@ -1488,6 +1501,10 @@ struct elf_backend_data
bool (*elf_backend_write_section)
(bfd *, struct bfd_link_info *, asection *, bfd_byte *);
+ /* This function adds glibc version dependency. */
+ void (*elf_backend_add_glibc_version_dependency)
+ (struct elf_find_verdep_info *);
+
/* This function, if defined, returns TRUE if it is section symbols
only that are considered local for the purpose of partitioning the
symbol table into local and global symbols. This should be NULL
@@ -2583,6 +2600,12 @@ extern bool _bfd_elf_link_output_relocs
(bfd *, asection *, Elf_Internal_Shdr *, Elf_Internal_Rela *,
struct elf_link_hash_entry **);
+extern void _bfd_elf_link_add_glibc_version_dependency
+ (struct elf_find_verdep_info *, const char *[]);
+
+extern void _bfd_elf_link_add_dt_relr_dependency
+ (struct elf_find_verdep_info *);
+
extern bool _bfd_elf_adjust_dynamic_copy
(struct bfd_link_info *, struct elf_link_hash_entry *, asection *);
diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index ec001599cc1..1a2e64c031f 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -5568,6 +5568,31 @@ elf_x86_64_link_setup_gnu_properties (struct bfd_link_info *info)
return _bfd_x86_elf_link_setup_gnu_properties (info, &init_table);
}
+static void
+elf_x86_64_add_glibc_version_dependency
+ (struct elf_find_verdep_info *rinfo)
+{
+ unsigned int i = 0;
+ const char *version[3] = { NULL, NULL, NULL };
+ struct elf_x86_link_hash_table *htab;
+
+ if (rinfo->info->enable_dt_relr)
+ {
+ version[i] = "GLIBC_ABI_DT_RELR";
+ i++;
+ }
+
+ htab = elf_x86_hash_table (rinfo->info, X86_64_ELF_DATA);
+ if (htab != NULL && htab->params->mark_plt)
+ {
+ version[i] = "GLIBC_2.36";
+ i++;
+ }
+
+ if (i != 0)
+ _bfd_elf_link_add_glibc_version_dependency (rinfo, version);
+}
+
static const struct bfd_elf_special_section
elf_x86_64_special_sections[]=
{
@@ -5652,6 +5677,8 @@ elf_x86_64_special_sections[]=
elf_x86_64_link_setup_gnu_properties
#define elf_backend_hide_symbol \
_bfd_x86_elf_hide_symbol
+#define elf_backend_add_glibc_version_dependency \
+ elf_x86_64_add_glibc_version_dependency
#undef elf64_bed
#define elf64_bed elf64_x86_64_bed
diff --git a/bfd/elflink.c b/bfd/elflink.c
index a577c957514..c2494b3e12e 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -46,19 +46,6 @@ struct elf_info_failed
bool failed;
};
-/* This structure is used to pass information to
- _bfd_elf_link_find_version_dependencies. */
-
-struct elf_find_verdep_info
-{
- /* General link information. */
- struct bfd_link_info *info;
- /* The number of dependencies. */
- unsigned int vers;
- /* Whether we had a failure. */
- bool failed;
-};
-
static bool _bfd_elf_fix_symbol_flags
(struct elf_link_hash_entry *, struct elf_info_failed *);
@@ -2217,64 +2204,64 @@ _bfd_elf_export_symbol (struct elf_link_hash_entry *h, void *data)
return true;
}
\f
-/* Return true if GLIBC_ABI_DT_RELR is added to the list of version
- dependencies successfully. GLIBC_ABI_DT_RELR will be put into the
- .gnu.version_r section. */
+/* Return the glibc version reference if VERSION_DEP is added to the
+ list of glibc version dependencies successfully. VERSION_DEP will
+ be put into the .gnu.version_r section. */
-static bool
-elf_link_add_dt_relr_dependency (struct elf_find_verdep_info *rinfo)
+static Elf_Internal_Verneed *
+elf_link_add_glibc_verneed (struct elf_find_verdep_info *rinfo,
+ Elf_Internal_Verneed *glibc_verref,
+ const char *version_dep)
{
- bfd *glibc_bfd = NULL;
Elf_Internal_Verneed *t;
Elf_Internal_Vernaux *a;
size_t amt;
- const char *relr = "GLIBC_ABI_DT_RELR";
- /* See if we already know about GLIBC_PRIVATE_DT_RELR. */
- for (t = elf_tdata (rinfo->info->output_bfd)->verref;
- t != NULL;
- t = t->vn_nextref)
+ if (glibc_verref != NULL)
{
- const char *soname = bfd_elf_get_dt_soname (t->vn_bfd);
- /* Skip the shared library if it isn't libc.so. */
- if (!soname || !startswith (soname, "libc.so."))
- continue;
+ t = glibc_verref;
for (a = t->vn_auxptr; a != NULL; a = a->vna_nextptr)
{
- /* Return if GLIBC_PRIVATE_DT_RELR dependency has been
- added. */
- if (a->vna_nodename == relr
- || strcmp (a->vna_nodename, relr) == 0)
- return true;
-
- /* Check if libc.so provides GLIBC_2.XX version. */
- if (!glibc_bfd && startswith (a->vna_nodename, "GLIBC_2."))
- glibc_bfd = t->vn_bfd;
+ /* Return if VERSION_DEP dependency has been added. */
+ if (a->vna_nodename == version_dep
+ || strcmp (a->vna_nodename, version_dep) == 0)
+ return t;
}
-
- break;
}
+ else
+ {
+ bool is_glibc;
- /* Skip if it isn't linked against glibc. */
- if (glibc_bfd == NULL)
- return true;
+ for (t = elf_tdata (rinfo->info->output_bfd)->verref;
+ t != NULL;
+ t = t->vn_nextref)
+ {
+ const char *soname = bfd_elf_get_dt_soname (t->vn_bfd);
+ if (soname != NULL && startswith (soname, "libc.so."))
+ break;
+ }
- /* This is a new version. Add it to tree we are building. */
- if (t == NULL)
- {
- amt = sizeof *t;
- t = (Elf_Internal_Verneed *) bfd_zalloc (rinfo->info->output_bfd,
- amt);
+ /* Skip the shared library if it isn't libc.so. */
if (t == NULL)
+ return t;
+
+ is_glibc = false;
+ for (a = t->vn_auxptr; a != NULL; a = a->vna_nextptr)
{
- rinfo->failed = true;
- return false;
+ /* Return if VERSION_DEP dependency has been added. */
+ if (a->vna_nodename == version_dep
+ || strcmp (a->vna_nodename, version_dep) == 0)
+ return t;
+
+ /* Check if libc.so provides GLIBC_2.XX version. */
+ if (!is_glibc && startswith (a->vna_nodename, "GLIBC_2."))
+ is_glibc = true;
}
- t->vn_bfd = glibc_bfd;
- t->vn_nextref = elf_tdata (rinfo->info->output_bfd)->verref;
- elf_tdata (rinfo->info->output_bfd)->verref = t;
+ /* Skip if it isn't linked against glibc. */
+ if (!is_glibc)
+ return NULL;
}
amt = sizeof *a;
@@ -2282,10 +2269,10 @@ elf_link_add_dt_relr_dependency (struct elf_find_verdep_info *rinfo)
if (a == NULL)
{
rinfo->failed = true;
- return false;
+ return NULL;
}
- a->vna_nodename = relr;
+ a->vna_nodename = version_dep;
a->vna_flags = 0;
a->vna_nextptr = t->vn_auxptr;
a->vna_other = rinfo->vers + 1;
@@ -2293,7 +2280,45 @@ elf_link_add_dt_relr_dependency (struct elf_find_verdep_info *rinfo)
t->vn_auxptr = a;
- return true;
+ return t;
+}
+
+/* Add VERSION_DEP to the list of version dependencies when linked
+ against glibc. */
+
+void
+_bfd_elf_link_add_glibc_version_dependency
+ (struct elf_find_verdep_info *rinfo,
+ const char *version_dep[])
+{
+ Elf_Internal_Verneed *t = NULL;
+
+ do
+ {
+ t = elf_link_add_glibc_verneed (rinfo, t, *version_dep);
+ /* Return if there is no glibc version reference. */
+ if (t == NULL)
+ return;
+ version_dep++;
+ }
+ while (*version_dep != NULL);
+}
+
+/* Add GLIBC_ABI_DT_RELR to the list of version dependencies when
+ linked against glibc. */
+
+void
+_bfd_elf_link_add_dt_relr_dependency (struct elf_find_verdep_info *rinfo)
+{
+ if (rinfo->info->enable_dt_relr)
+ {
+ const char *version[] =
+ {
+ "GLIBC_ABI_DT_RELR",
+ NULL
+ };
+ _bfd_elf_link_add_glibc_version_dependency (rinfo, version);
+ }
}
/* Look through the symbols which are defined in other shared
@@ -7047,12 +7072,9 @@ bfd_elf_size_dynamic_sections (bfd *output_bfd,
if (sinfo.failed)
return false;
- if (info->enable_dt_relr)
- {
- elf_link_add_dt_relr_dependency (&sinfo);
- if (sinfo.failed)
- return false;
- }
+ bed->elf_backend_add_glibc_version_dependency (&sinfo);
+ if (sinfo.failed)
+ return false;
if (elf_tdata (output_bfd)->verref == NULL)
s->flags |= SEC_EXCLUDE;
diff --git a/bfd/elfxx-target.h b/bfd/elfxx-target.h
index d4b14a022e3..a7f2fc6e320 100644
--- a/bfd/elfxx-target.h
+++ b/bfd/elfxx-target.h
@@ -667,6 +667,10 @@
#ifndef elf_backend_write_section
#define elf_backend_write_section NULL
#endif
+#ifndef elf_backend_add_glibc_version_dependency
+#define elf_backend_add_glibc_version_dependency \
+ _bfd_elf_link_add_dt_relr_dependency
+#endif
#ifndef elf_backend_elfsym_local_is_section
#define elf_backend_elfsym_local_is_section NULL
#endif
@@ -897,6 +901,7 @@ static const struct elf_backend_data elfNN_bed =
elf_backend_can_make_multiple_eh_frame,
elf_backend_encode_eh_address,
elf_backend_write_section,
+ elf_backend_add_glibc_version_dependency,
elf_backend_elfsym_local_is_section,
elf_backend_mips_irix_compat,
elf_backend_mips_rtype_to_howto,
diff --git a/ld/testsuite/ld-x86-64/mark-plt-1a.rd b/ld/testsuite/ld-x86-64/mark-plt-1a.rd
new file mode 100644
index 00000000000..1234fbe038c
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/mark-plt-1a.rd
@@ -0,0 +1,7 @@
+#...
+Version needs section '.gnu.version_r' contains 1 entry:
+ Addr: 0x[0-9a-f]+ +Offset: 0x[0-9a-f]+ +Link: +[0-9]+ +\(.dynstr\)
+ +0+: Version: 1 +File: libc\.so\.6(|\.1) +Cnt: +[0-9]+
+#...
+ 0x[a-f0-9]+: Name: GLIBC_2.36 Flags: none Version: [0-9]+
+#pass
diff --git a/ld/testsuite/ld-x86-64/mark-plt-1b.rd b/ld/testsuite/ld-x86-64/mark-plt-1b.rd
new file mode 100644
index 00000000000..6556a6d939e
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/mark-plt-1b.rd
@@ -0,0 +1,7 @@
+#...
+Version needs section '.gnu.version_r' contains 1 entry:
+ Addr: 0x[0-9a-f]+ +Offset: 0x[0-9a-f]+ +Link: +[0-9]+ +\(.dynstr\)
+ +0+: Version: 1 +File: libc\.so\.6(|\.1) +Cnt: +[0-9]+
+#...
+ 0x[a-f0-9]+: Name: GLIBC_ABI_DT_RELR Flags: none Version: [0-9]+
+#pass
diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp
index 0af9f047600..d17bb9b7d7e 100644
--- a/ld/testsuite/ld-x86-64/x86-64.exp
+++ b/ld/testsuite/ld-x86-64/x86-64.exp
@@ -2257,4 +2257,18 @@ run_dump_test "mark-plt-1b-x32"
run_dump_test "mark-plt-1c-x32"
run_dump_test "mark-plt-1d-x32"
+if { [check_compiler_available] } {
+ run_cc_link_tests [list \
+ [list \
+ "Build mark-plt-1.so" \
+ "-shared -Wl,-z,mark-plt,-z,pack-relative-relocs" \
+ "-fPIC" \
+ { mark-plt-1.s } \
+ {{readelf {-W --version-info} mark-plt-1a.rd} \
+ {readelf {-W --version-info} mark-plt-1b.rd}} \
+ "mark-plt-1.so" \
+ ] \
+ ]
+}
+
set ASFLAGS "$saved_ASFLAGS"
--
2.43.0
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v2 2/2] ld: Add --enable-mark-plt configure option
2024-01-06 22:09 [PATCH v2 0/2] Improve -z mark-plt H.J. Lu
2024-01-06 22:10 ` [PATCH v2 1/2] elf: Add elf_backend_add_glibc_version_dependency H.J. Lu
@ 2024-01-06 22:10 ` H.J. Lu
2024-01-08 15:24 ` H.J. Lu
1 sibling, 1 reply; 7+ messages in thread
From: H.J. Lu @ 2024-01-06 22:10 UTC (permalink / raw)
To: binutils
Add --enable-mark-plt linker configure option to mark PLT entries with
DT_X86_64_PLT, DT_X86_64_PLTSZ and DT_X86_64_PLTENT dynamic tags by
default.
* NEWS: Mention -z mark-plt/-z nomark-plt and --enable-mark-plt.
* config.in: Regenerated.
* configure: Likewise.
* configure.ac: Add --enable-mark-plt.
(DEFAULT_LD_Z_MARK_PLT): New AC_DEFINE_UNQUOTED.
* emulparams/x86-64-plt.sh (PARSE_AND_LIST_OPTIONS_X86_64_PLT):
Support DEFAULT_LD_Z_MARK_PLT.
* emultempl/elf-x86.em (elf_x86_64_before_parse): New function.
(LDEMUL_BEFORE_PARSE): New. Set to elf_x86_64_before_parse for
x86-64 targets.
---
ld/NEWS | 5 +++++
ld/config.in | 4 ++++
ld/configure | 26 ++++++++++++++++++++++++--
ld/configure.ac | 17 +++++++++++++++++
ld/emulparams/x86-64-plt.sh | 7 ++++++-
ld/emultempl/elf-x86.em | 17 +++++++++++++++++
6 files changed, 73 insertions(+), 3 deletions(-)
diff --git a/ld/NEWS b/ld/NEWS
index a2c0b7fbcfe..cedd0d72d1b 100644
--- a/ld/NEWS
+++ b/ld/NEWS
@@ -1,5 +1,10 @@
-*- text -*-
+* Add -z mark-plt/-z nomark-plt options to x86-64 ELF linker to mark PLT
+ entries with DT_X86_64_PLT, DT_X86_64_PLTSZ and DT_X86_64_PLTENT dynamic
+ tags. Also added --enable-mark-plt configure option to mark PLT entries
+ by default.
+
* Support Intel APX relocations.
* On RISC-V, add ld target option --[no-]check-uleb128. Should rebuild the
diff --git a/ld/config.in b/ld/config.in
index 86d90d53752..52d62f06ff0 100644
--- a/ld/config.in
+++ b/ld/config.in
@@ -45,6 +45,10 @@
default. */
#undef DEFAULT_LD_WARN_RWX_SEGMENTS
+/* Define to 1 if you want to enable -z mark-plt in ELF x86-64 linker by
+ default. */
+#undef DEFAULT_LD_Z_MARK_PLT
+
/* Define to 1 if you want to enable -z relro in ELF linker by default. */
#undef DEFAULT_LD_Z_RELRO
diff --git a/ld/configure b/ld/configure
index 07eb669d906..b7f29ca68b7 100755
--- a/ld/configure
+++ b/ld/configure
@@ -852,6 +852,7 @@ enable_new_dtags
enable_relro
enable_textrel_check
enable_separate_code
+enable_mark_plt
enable_warn_execstack
enable_error_execstack
enable_warn_rwx_segments
@@ -1546,6 +1547,7 @@ Optional Features:
--enable-textrel-check=[yes|no|warning|error]
enable DT_TEXTREL check in ELF linker
--enable-separate-code enable -z separate-code in ELF linker by default
+ --enable-mark-plt enable -z mark-plt in ELF x86-64 linker by default
--enable-warn-execstack enable warnings when creating an executable stack
--enable-error-execstack
turn executable stack warnings into errors
@@ -11681,7 +11683,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 11684 "configure"
+#line 11686 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@@ -11787,7 +11789,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 11790 "configure"
+#line 11792 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@@ -15682,6 +15684,17 @@ esac
fi
+# Decide if -z mark-plt should be enabled in ELF x86-64 linker by default.
+ac_default_ld_z_mark_plt=unset
+# Check whether --enable-mark-plt was given.
+if test "${enable_mark_plt+set}" = set; then :
+ enableval=$enable_mark_plt; case "${enableval}" in
+ yes) ac_default_ld_z_mark_plt=1 ;;
+ no) ac_default_ld_z_mark_plt=0 ;;
+esac
+fi
+
+
# By default warn when an executable stack is created due to object files
# requesting such, not when the user specifies -z execstack.
@@ -19365,6 +19378,15 @@ cat >>confdefs.h <<_ACEOF
_ACEOF
+if test "${ac_default_ld_z_mark_plt}" = unset; then
+ ac_default_ld_z_mark_plt=0
+fi
+
+cat >>confdefs.h <<_ACEOF
+#define DEFAULT_LD_Z_MARK_PLT $ac_default_ld_z_mark_plt
+_ACEOF
+
+
cat >>confdefs.h <<_ACEOF
diff --git a/ld/configure.ac b/ld/configure.ac
index b46f415fe9b..4a11787ae71 100644
--- a/ld/configure.ac
+++ b/ld/configure.ac
@@ -213,6 +213,16 @@ AC_ARG_ENABLE(separate-code,
no) ac_default_ld_z_separate_code=0 ;;
esac])
+# Decide if -z mark-plt should be enabled in ELF x86-64 linker by default.
+ac_default_ld_z_mark_plt=unset
+AC_ARG_ENABLE(mark-plt,
+ AS_HELP_STRING([--enable-mark-plt],
+ [enable -z mark-plt in ELF x86-64 linker by default]),
+[case "${enableval}" in
+ yes) ac_default_ld_z_mark_plt=1 ;;
+ no) ac_default_ld_z_mark_plt=0 ;;
+esac])
+
# By default warn when an executable stack is created due to object files
# requesting such, not when the user specifies -z execstack.
@@ -562,6 +572,13 @@ AC_DEFINE_UNQUOTED(DEFAULT_LD_Z_SEPARATE_CODE,
$ac_default_ld_z_separate_code,
[Define to 1 if you want to enable -z separate-code in ELF linker by default.])
+if test "${ac_default_ld_z_mark_plt}" = unset; then
+ ac_default_ld_z_mark_plt=0
+fi
+AC_DEFINE_UNQUOTED(DEFAULT_LD_Z_MARK_PLT,
+ $ac_default_ld_z_mark_plt,
+ [Define to 1 if you want to enable -z mark-plt in ELF x86-64 linker by default.])
+
AC_DEFINE_UNQUOTED(DEFAULT_LD_WARN_EXECSTACK,
$ac_default_ld_warn_execstack,
diff --git a/ld/emulparams/x86-64-plt.sh b/ld/emulparams/x86-64-plt.sh
index 92732401dc7..d1a5c65937f 100644
--- a/ld/emulparams/x86-64-plt.sh
+++ b/ld/emulparams/x86-64-plt.sh
@@ -1,5 +1,10 @@
PARSE_AND_LIST_OPTIONS_X86_64_PLT='
- fprintf (file, _("\
+ if (DEFAULT_LD_Z_MARK_PLT != 0)
+ fprintf (file, _("\
+ -z mark-plt Mark PLT with dynamic tags (default)\n\
+ -z nomark-plt Do not mark PLT with dynamic tags\n"));
+ else
+ fprintf (file, _("\
-z mark-plt Mark PLT with dynamic tags\n\
-z nomark-plt Do not mark PLT with dynamic tags (default)\n"));
'
diff --git a/ld/emultempl/elf-x86.em b/ld/emultempl/elf-x86.em
index 0ccad72ab9a..a6eda14253f 100644
--- a/ld/emultempl/elf-x86.em
+++ b/ld/emultempl/elf-x86.em
@@ -56,3 +56,20 @@ EOF
LDEMUL_BEFORE_PARSE=elf_x86_before_parse
fi
+
+case x${OUTPUT_FORMAT} in
+ x*x86-64*)
+fragment <<EOF
+
+static void
+elf_x86_64_before_parse (void)
+{
+ params.mark_plt = DEFAULT_LD_Z_MARK_PLT;
+
+ elf_x86_before_parse ();
+}
+EOF
+
+ LDEMUL_BEFORE_PARSE=elf_x86_64_before_parse
+ ;;
+esac
--
2.43.0
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2 1/2] elf: Add elf_backend_add_glibc_version_dependency
2024-01-06 22:10 ` [PATCH v2 1/2] elf: Add elf_backend_add_glibc_version_dependency H.J. Lu
@ 2024-01-08 15:22 ` H.J. Lu
2024-01-09 13:45 ` H.J. Lu
0 siblings, 1 reply; 7+ messages in thread
From: H.J. Lu @ 2024-01-08 15:22 UTC (permalink / raw)
To: Binutils; +Cc: Alan Modra, Nick Clifton
On Sat, Jan 6, 2024 at 2:10 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> When -z mark-plt is used to add DT_X86_64_PLT, DT_X86_64_PLTSZ and
> DT_X86_64_PLTENT, the r_addend field of the R_X86_64_JUMP_SLOT relocation
> stores the offset of the indirect branch instruction. However, glibc
> versions which don't have this commit in glibc 2.36:
>
> commit f8587a61892cbafd98ce599131bf4f103466f084
> Author: H.J. Lu <hjl.tools@gmail.com>
> Date: Fri May 20 19:21:48 2022 -0700
>
> x86-64: Ignore r_addend for R_X86_64_GLOB_DAT/R_X86_64_JUMP_SLOT
>
> According to x86-64 psABI, r_addend should be ignored for R_X86_64_GLOB_DAT
> and R_X86_64_JUMP_SLOT. Since linkers always set their r_addends to 0, we
> can ignore their r_addends.
>
> Reviewed-by: Fangrui Song <maskray@google.com>
>
> won't ignore the r_addend value in the R_X86_64_JUMP_SLOT relocation.
> Although this commit has been backported to glibc 2.33/2.34/2.35 release
> branches, it is safer to require glibc 2.36 for such binaries.
>
> Extend the glibc version dependency of GLIBC_ABI_DT_RELR for DT_RELR to
> also add GLIBC_2.36 version dependency for -z mark-plt on the the shared C
> library if it provides a GLIBC_2.XX symbol version.
>
> * elflink.c (elf_find_verdep_info): Moved to ...
> * elf-bfd.h (elf_find_verdep_info): Here.
> (elf_backend_data): Add elf_backend_add_glibc_version_dependency.
> (_bfd_elf_link_add_glibc_version_dependency): New function.
> (_bfd_elf_link_add_dt_relr_dependency): Likewise.
> * elf64-x86-64.c (elf_x86_64_add_glibc_version_dependency):
> Likewise.
> (elf_backend_add_glibc_version_dependency): New.
> * elflink.c (elf_link_add_dt_relr_dependency): Renamed to ...
> (elf_link_add_glibc_verneed): This. Modified to support other
> glibc dependencies.
> (_bfd_elf_link_add_glibc_version_dependency): Likewise.
> (_bfd_elf_link_add_dt_relr_dependency): Likewise.
> (bfd_elf_size_dynamic_sections): Call
> elf_backend_add_glibc_version_dependency instead of
> elf_link_add_dt_relr_dependency.
> * elfxx-target.h (elf_backend_add_glibc_version_dependency): New.
> (elfNN_bed): Add elf_backend_add_glibc_version_dependency.
>
> ld/
>
> * testsuite/ld-x86-64/mark-plt-1a.rd: New file.
> * testsuite/ld-x86-64/mark-plt-1b.rd: Likewise.
> * testsuite/ld-x86-64/x86-64.exp: Run -z mark-plt test for
> GLIBC_2.36 dependency.
> ---
> bfd/elf-bfd.h | 23 ++++
> bfd/elf64-x86-64.c | 27 +++++
> bfd/elflink.c | 146 +++++++++++++++-----------
> bfd/elfxx-target.h | 5 +
> ld/testsuite/ld-x86-64/mark-plt-1a.rd | 7 ++
> ld/testsuite/ld-x86-64/mark-plt-1b.rd | 7 ++
> ld/testsuite/ld-x86-64/x86-64.exp | 14 +++
> 7 files changed, 167 insertions(+), 62 deletions(-)
> create mode 100644 ld/testsuite/ld-x86-64/mark-plt-1a.rd
> create mode 100644 ld/testsuite/ld-x86-64/mark-plt-1b.rd
>
> diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
> index a611349e3d9..3ed22fa6c52 100644
> --- a/bfd/elf-bfd.h
> +++ b/bfd/elf-bfd.h
> @@ -957,6 +957,19 @@ typedef struct elf_property_list
> struct elf_property property;
> } elf_property_list;
>
> +/* This structure is used to pass information to
> + elf_backend_add_glibc_version_dependency. */
> +
> +struct elf_find_verdep_info
> +{
> + /* General link information. */
> + struct bfd_link_info *info;
> + /* The number of dependencies. */
> + unsigned int vers;
> + /* Whether we had a failure. */
> + bool failed;
> +};
> +
> struct bfd_elf_section_reloc_data;
>
> struct elf_backend_data
> @@ -1488,6 +1501,10 @@ struct elf_backend_data
> bool (*elf_backend_write_section)
> (bfd *, struct bfd_link_info *, asection *, bfd_byte *);
>
> + /* This function adds glibc version dependency. */
> + void (*elf_backend_add_glibc_version_dependency)
> + (struct elf_find_verdep_info *);
> +
> /* This function, if defined, returns TRUE if it is section symbols
> only that are considered local for the purpose of partitioning the
> symbol table into local and global symbols. This should be NULL
> @@ -2583,6 +2600,12 @@ extern bool _bfd_elf_link_output_relocs
> (bfd *, asection *, Elf_Internal_Shdr *, Elf_Internal_Rela *,
> struct elf_link_hash_entry **);
>
> +extern void _bfd_elf_link_add_glibc_version_dependency
> + (struct elf_find_verdep_info *, const char *[]);
> +
> +extern void _bfd_elf_link_add_dt_relr_dependency
> + (struct elf_find_verdep_info *);
> +
> extern bool _bfd_elf_adjust_dynamic_copy
> (struct bfd_link_info *, struct elf_link_hash_entry *, asection *);
>
> diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
> index ec001599cc1..1a2e64c031f 100644
> --- a/bfd/elf64-x86-64.c
> +++ b/bfd/elf64-x86-64.c
> @@ -5568,6 +5568,31 @@ elf_x86_64_link_setup_gnu_properties (struct bfd_link_info *info)
> return _bfd_x86_elf_link_setup_gnu_properties (info, &init_table);
> }
>
> +static void
> +elf_x86_64_add_glibc_version_dependency
> + (struct elf_find_verdep_info *rinfo)
> +{
> + unsigned int i = 0;
> + const char *version[3] = { NULL, NULL, NULL };
> + struct elf_x86_link_hash_table *htab;
> +
> + if (rinfo->info->enable_dt_relr)
> + {
> + version[i] = "GLIBC_ABI_DT_RELR";
> + i++;
> + }
> +
> + htab = elf_x86_hash_table (rinfo->info, X86_64_ELF_DATA);
> + if (htab != NULL && htab->params->mark_plt)
> + {
> + version[i] = "GLIBC_2.36";
> + i++;
> + }
> +
> + if (i != 0)
> + _bfd_elf_link_add_glibc_version_dependency (rinfo, version);
> +}
> +
> static const struct bfd_elf_special_section
> elf_x86_64_special_sections[]=
> {
> @@ -5652,6 +5677,8 @@ elf_x86_64_special_sections[]=
> elf_x86_64_link_setup_gnu_properties
> #define elf_backend_hide_symbol \
> _bfd_x86_elf_hide_symbol
> +#define elf_backend_add_glibc_version_dependency \
> + elf_x86_64_add_glibc_version_dependency
>
> #undef elf64_bed
> #define elf64_bed elf64_x86_64_bed
> diff --git a/bfd/elflink.c b/bfd/elflink.c
> index a577c957514..c2494b3e12e 100644
> --- a/bfd/elflink.c
> +++ b/bfd/elflink.c
> @@ -46,19 +46,6 @@ struct elf_info_failed
> bool failed;
> };
>
> -/* This structure is used to pass information to
> - _bfd_elf_link_find_version_dependencies. */
> -
> -struct elf_find_verdep_info
> -{
> - /* General link information. */
> - struct bfd_link_info *info;
> - /* The number of dependencies. */
> - unsigned int vers;
> - /* Whether we had a failure. */
> - bool failed;
> -};
> -
> static bool _bfd_elf_fix_symbol_flags
> (struct elf_link_hash_entry *, struct elf_info_failed *);
>
> @@ -2217,64 +2204,64 @@ _bfd_elf_export_symbol (struct elf_link_hash_entry *h, void *data)
> return true;
> }
>
> -/* Return true if GLIBC_ABI_DT_RELR is added to the list of version
> - dependencies successfully. GLIBC_ABI_DT_RELR will be put into the
> - .gnu.version_r section. */
> +/* Return the glibc version reference if VERSION_DEP is added to the
> + list of glibc version dependencies successfully. VERSION_DEP will
> + be put into the .gnu.version_r section. */
>
> -static bool
> -elf_link_add_dt_relr_dependency (struct elf_find_verdep_info *rinfo)
> +static Elf_Internal_Verneed *
> +elf_link_add_glibc_verneed (struct elf_find_verdep_info *rinfo,
> + Elf_Internal_Verneed *glibc_verref,
> + const char *version_dep)
> {
> - bfd *glibc_bfd = NULL;
> Elf_Internal_Verneed *t;
> Elf_Internal_Vernaux *a;
> size_t amt;
> - const char *relr = "GLIBC_ABI_DT_RELR";
>
> - /* See if we already know about GLIBC_PRIVATE_DT_RELR. */
> - for (t = elf_tdata (rinfo->info->output_bfd)->verref;
> - t != NULL;
> - t = t->vn_nextref)
> + if (glibc_verref != NULL)
> {
> - const char *soname = bfd_elf_get_dt_soname (t->vn_bfd);
> - /* Skip the shared library if it isn't libc.so. */
> - if (!soname || !startswith (soname, "libc.so."))
> - continue;
> + t = glibc_verref;
>
> for (a = t->vn_auxptr; a != NULL; a = a->vna_nextptr)
> {
> - /* Return if GLIBC_PRIVATE_DT_RELR dependency has been
> - added. */
> - if (a->vna_nodename == relr
> - || strcmp (a->vna_nodename, relr) == 0)
> - return true;
> -
> - /* Check if libc.so provides GLIBC_2.XX version. */
> - if (!glibc_bfd && startswith (a->vna_nodename, "GLIBC_2."))
> - glibc_bfd = t->vn_bfd;
> + /* Return if VERSION_DEP dependency has been added. */
> + if (a->vna_nodename == version_dep
> + || strcmp (a->vna_nodename, version_dep) == 0)
> + return t;
> }
> -
> - break;
> }
> + else
> + {
> + bool is_glibc;
>
> - /* Skip if it isn't linked against glibc. */
> - if (glibc_bfd == NULL)
> - return true;
> + for (t = elf_tdata (rinfo->info->output_bfd)->verref;
> + t != NULL;
> + t = t->vn_nextref)
> + {
> + const char *soname = bfd_elf_get_dt_soname (t->vn_bfd);
> + if (soname != NULL && startswith (soname, "libc.so."))
> + break;
> + }
>
> - /* This is a new version. Add it to tree we are building. */
> - if (t == NULL)
> - {
> - amt = sizeof *t;
> - t = (Elf_Internal_Verneed *) bfd_zalloc (rinfo->info->output_bfd,
> - amt);
> + /* Skip the shared library if it isn't libc.so. */
> if (t == NULL)
> + return t;
> +
> + is_glibc = false;
> + for (a = t->vn_auxptr; a != NULL; a = a->vna_nextptr)
> {
> - rinfo->failed = true;
> - return false;
> + /* Return if VERSION_DEP dependency has been added. */
> + if (a->vna_nodename == version_dep
> + || strcmp (a->vna_nodename, version_dep) == 0)
> + return t;
> +
> + /* Check if libc.so provides GLIBC_2.XX version. */
> + if (!is_glibc && startswith (a->vna_nodename, "GLIBC_2."))
> + is_glibc = true;
> }
>
> - t->vn_bfd = glibc_bfd;
> - t->vn_nextref = elf_tdata (rinfo->info->output_bfd)->verref;
> - elf_tdata (rinfo->info->output_bfd)->verref = t;
> + /* Skip if it isn't linked against glibc. */
> + if (!is_glibc)
> + return NULL;
> }
>
> amt = sizeof *a;
> @@ -2282,10 +2269,10 @@ elf_link_add_dt_relr_dependency (struct elf_find_verdep_info *rinfo)
> if (a == NULL)
> {
> rinfo->failed = true;
> - return false;
> + return NULL;
> }
>
> - a->vna_nodename = relr;
> + a->vna_nodename = version_dep;
> a->vna_flags = 0;
> a->vna_nextptr = t->vn_auxptr;
> a->vna_other = rinfo->vers + 1;
> @@ -2293,7 +2280,45 @@ elf_link_add_dt_relr_dependency (struct elf_find_verdep_info *rinfo)
>
> t->vn_auxptr = a;
>
> - return true;
> + return t;
> +}
> +
> +/* Add VERSION_DEP to the list of version dependencies when linked
> + against glibc. */
> +
> +void
> +_bfd_elf_link_add_glibc_version_dependency
> + (struct elf_find_verdep_info *rinfo,
> + const char *version_dep[])
> +{
> + Elf_Internal_Verneed *t = NULL;
> +
> + do
> + {
> + t = elf_link_add_glibc_verneed (rinfo, t, *version_dep);
> + /* Return if there is no glibc version reference. */
> + if (t == NULL)
> + return;
> + version_dep++;
> + }
> + while (*version_dep != NULL);
> +}
> +
> +/* Add GLIBC_ABI_DT_RELR to the list of version dependencies when
> + linked against glibc. */
> +
> +void
> +_bfd_elf_link_add_dt_relr_dependency (struct elf_find_verdep_info *rinfo)
> +{
> + if (rinfo->info->enable_dt_relr)
> + {
> + const char *version[] =
> + {
> + "GLIBC_ABI_DT_RELR",
> + NULL
> + };
> + _bfd_elf_link_add_glibc_version_dependency (rinfo, version);
> + }
> }
>
> /* Look through the symbols which are defined in other shared
> @@ -7047,12 +7072,9 @@ bfd_elf_size_dynamic_sections (bfd *output_bfd,
> if (sinfo.failed)
> return false;
>
> - if (info->enable_dt_relr)
> - {
> - elf_link_add_dt_relr_dependency (&sinfo);
> - if (sinfo.failed)
> - return false;
> - }
> + bed->elf_backend_add_glibc_version_dependency (&sinfo);
> + if (sinfo.failed)
> + return false;
>
> if (elf_tdata (output_bfd)->verref == NULL)
> s->flags |= SEC_EXCLUDE;
> diff --git a/bfd/elfxx-target.h b/bfd/elfxx-target.h
> index d4b14a022e3..a7f2fc6e320 100644
> --- a/bfd/elfxx-target.h
> +++ b/bfd/elfxx-target.h
> @@ -667,6 +667,10 @@
> #ifndef elf_backend_write_section
> #define elf_backend_write_section NULL
> #endif
> +#ifndef elf_backend_add_glibc_version_dependency
> +#define elf_backend_add_glibc_version_dependency \
> + _bfd_elf_link_add_dt_relr_dependency
> +#endif
> #ifndef elf_backend_elfsym_local_is_section
> #define elf_backend_elfsym_local_is_section NULL
> #endif
> @@ -897,6 +901,7 @@ static const struct elf_backend_data elfNN_bed =
> elf_backend_can_make_multiple_eh_frame,
> elf_backend_encode_eh_address,
> elf_backend_write_section,
> + elf_backend_add_glibc_version_dependency,
> elf_backend_elfsym_local_is_section,
> elf_backend_mips_irix_compat,
> elf_backend_mips_rtype_to_howto,
> diff --git a/ld/testsuite/ld-x86-64/mark-plt-1a.rd b/ld/testsuite/ld-x86-64/mark-plt-1a.rd
> new file mode 100644
> index 00000000000..1234fbe038c
> --- /dev/null
> +++ b/ld/testsuite/ld-x86-64/mark-plt-1a.rd
> @@ -0,0 +1,7 @@
> +#...
> +Version needs section '.gnu.version_r' contains 1 entry:
> + Addr: 0x[0-9a-f]+ +Offset: 0x[0-9a-f]+ +Link: +[0-9]+ +\(.dynstr\)
> + +0+: Version: 1 +File: libc\.so\.6(|\.1) +Cnt: +[0-9]+
> +#...
> + 0x[a-f0-9]+: Name: GLIBC_2.36 Flags: none Version: [0-9]+
> +#pass
> diff --git a/ld/testsuite/ld-x86-64/mark-plt-1b.rd b/ld/testsuite/ld-x86-64/mark-plt-1b.rd
> new file mode 100644
> index 00000000000..6556a6d939e
> --- /dev/null
> +++ b/ld/testsuite/ld-x86-64/mark-plt-1b.rd
> @@ -0,0 +1,7 @@
> +#...
> +Version needs section '.gnu.version_r' contains 1 entry:
> + Addr: 0x[0-9a-f]+ +Offset: 0x[0-9a-f]+ +Link: +[0-9]+ +\(.dynstr\)
> + +0+: Version: 1 +File: libc\.so\.6(|\.1) +Cnt: +[0-9]+
> +#...
> + 0x[a-f0-9]+: Name: GLIBC_ABI_DT_RELR Flags: none Version: [0-9]+
> +#pass
> diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp
> index 0af9f047600..d17bb9b7d7e 100644
> --- a/ld/testsuite/ld-x86-64/x86-64.exp
> +++ b/ld/testsuite/ld-x86-64/x86-64.exp
> @@ -2257,4 +2257,18 @@ run_dump_test "mark-plt-1b-x32"
> run_dump_test "mark-plt-1c-x32"
> run_dump_test "mark-plt-1d-x32"
>
> +if { [check_compiler_available] } {
> + run_cc_link_tests [list \
> + [list \
> + "Build mark-plt-1.so" \
> + "-shared -Wl,-z,mark-plt,-z,pack-relative-relocs" \
> + "-fPIC" \
> + { mark-plt-1.s } \
> + {{readelf {-W --version-info} mark-plt-1a.rd} \
> + {readelf {-W --version-info} mark-plt-1b.rd}} \
> + "mark-plt-1.so" \
> + ] \
> + ]
> +}
> +
> set ASFLAGS "$saved_ASFLAGS"
> --
> 2.43.0
>
Nick, Alan,
Any comments?
Thanks.
--
H.J.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2 2/2] ld: Add --enable-mark-plt configure option
2024-01-06 22:10 ` [PATCH v2 2/2] ld: Add --enable-mark-plt configure option H.J. Lu
@ 2024-01-08 15:24 ` H.J. Lu
2024-01-09 13:46 ` H.J. Lu
0 siblings, 1 reply; 7+ messages in thread
From: H.J. Lu @ 2024-01-08 15:24 UTC (permalink / raw)
To: binutils
On Sat, Jan 6, 2024 at 2:10 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> Add --enable-mark-plt linker configure option to mark PLT entries with
> DT_X86_64_PLT, DT_X86_64_PLTSZ and DT_X86_64_PLTENT dynamic tags by
> default.
>
> * NEWS: Mention -z mark-plt/-z nomark-plt and --enable-mark-plt.
> * config.in: Regenerated.
> * configure: Likewise.
> * configure.ac: Add --enable-mark-plt.
> (DEFAULT_LD_Z_MARK_PLT): New AC_DEFINE_UNQUOTED.
> * emulparams/x86-64-plt.sh (PARSE_AND_LIST_OPTIONS_X86_64_PLT):
> Support DEFAULT_LD_Z_MARK_PLT.
> * emultempl/elf-x86.em (elf_x86_64_before_parse): New function.
> (LDEMUL_BEFORE_PARSE): New. Set to elf_x86_64_before_parse for
> x86-64 targets.
> ---
> ld/NEWS | 5 +++++
> ld/config.in | 4 ++++
> ld/configure | 26 ++++++++++++++++++++++++--
> ld/configure.ac | 17 +++++++++++++++++
> ld/emulparams/x86-64-plt.sh | 7 ++++++-
> ld/emultempl/elf-x86.em | 17 +++++++++++++++++
> 6 files changed, 73 insertions(+), 3 deletions(-)
>
> diff --git a/ld/NEWS b/ld/NEWS
> index a2c0b7fbcfe..cedd0d72d1b 100644
> --- a/ld/NEWS
> +++ b/ld/NEWS
> @@ -1,5 +1,10 @@
> -*- text -*-
>
> +* Add -z mark-plt/-z nomark-plt options to x86-64 ELF linker to mark PLT
> + entries with DT_X86_64_PLT, DT_X86_64_PLTSZ and DT_X86_64_PLTENT dynamic
> + tags. Also added --enable-mark-plt configure option to mark PLT entries
> + by default.
> +
> * Support Intel APX relocations.
>
> * On RISC-V, add ld target option --[no-]check-uleb128. Should rebuild the
> diff --git a/ld/config.in b/ld/config.in
> index 86d90d53752..52d62f06ff0 100644
> --- a/ld/config.in
> +++ b/ld/config.in
> @@ -45,6 +45,10 @@
> default. */
> #undef DEFAULT_LD_WARN_RWX_SEGMENTS
>
> +/* Define to 1 if you want to enable -z mark-plt in ELF x86-64 linker by
> + default. */
> +#undef DEFAULT_LD_Z_MARK_PLT
> +
> /* Define to 1 if you want to enable -z relro in ELF linker by default. */
> #undef DEFAULT_LD_Z_RELRO
>
> diff --git a/ld/configure b/ld/configure
> index 07eb669d906..b7f29ca68b7 100755
> --- a/ld/configure
> +++ b/ld/configure
> @@ -852,6 +852,7 @@ enable_new_dtags
> enable_relro
> enable_textrel_check
> enable_separate_code
> +enable_mark_plt
> enable_warn_execstack
> enable_error_execstack
> enable_warn_rwx_segments
> @@ -1546,6 +1547,7 @@ Optional Features:
> --enable-textrel-check=[yes|no|warning|error]
> enable DT_TEXTREL check in ELF linker
> --enable-separate-code enable -z separate-code in ELF linker by default
> + --enable-mark-plt enable -z mark-plt in ELF x86-64 linker by default
> --enable-warn-execstack enable warnings when creating an executable stack
> --enable-error-execstack
> turn executable stack warnings into errors
> @@ -11681,7 +11683,7 @@ else
> lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
> lt_status=$lt_dlunknown
> cat > conftest.$ac_ext <<_LT_EOF
> -#line 11684 "configure"
> +#line 11686 "configure"
> #include "confdefs.h"
>
> #if HAVE_DLFCN_H
> @@ -11787,7 +11789,7 @@ else
> lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
> lt_status=$lt_dlunknown
> cat > conftest.$ac_ext <<_LT_EOF
> -#line 11790 "configure"
> +#line 11792 "configure"
> #include "confdefs.h"
>
> #if HAVE_DLFCN_H
> @@ -15682,6 +15684,17 @@ esac
> fi
>
>
> +# Decide if -z mark-plt should be enabled in ELF x86-64 linker by default.
> +ac_default_ld_z_mark_plt=unset
> +# Check whether --enable-mark-plt was given.
> +if test "${enable_mark_plt+set}" = set; then :
> + enableval=$enable_mark_plt; case "${enableval}" in
> + yes) ac_default_ld_z_mark_plt=1 ;;
> + no) ac_default_ld_z_mark_plt=0 ;;
> +esac
> +fi
> +
> +
>
> # By default warn when an executable stack is created due to object files
> # requesting such, not when the user specifies -z execstack.
> @@ -19365,6 +19378,15 @@ cat >>confdefs.h <<_ACEOF
> _ACEOF
>
>
> +if test "${ac_default_ld_z_mark_plt}" = unset; then
> + ac_default_ld_z_mark_plt=0
> +fi
> +
> +cat >>confdefs.h <<_ACEOF
> +#define DEFAULT_LD_Z_MARK_PLT $ac_default_ld_z_mark_plt
> +_ACEOF
> +
> +
>
>
> cat >>confdefs.h <<_ACEOF
> diff --git a/ld/configure.ac b/ld/configure.ac
> index b46f415fe9b..4a11787ae71 100644
> --- a/ld/configure.ac
> +++ b/ld/configure.ac
> @@ -213,6 +213,16 @@ AC_ARG_ENABLE(separate-code,
> no) ac_default_ld_z_separate_code=0 ;;
> esac])
>
> +# Decide if -z mark-plt should be enabled in ELF x86-64 linker by default.
> +ac_default_ld_z_mark_plt=unset
> +AC_ARG_ENABLE(mark-plt,
> + AS_HELP_STRING([--enable-mark-plt],
> + [enable -z mark-plt in ELF x86-64 linker by default]),
> +[case "${enableval}" in
> + yes) ac_default_ld_z_mark_plt=1 ;;
> + no) ac_default_ld_z_mark_plt=0 ;;
> +esac])
> +
>
> # By default warn when an executable stack is created due to object files
> # requesting such, not when the user specifies -z execstack.
> @@ -562,6 +572,13 @@ AC_DEFINE_UNQUOTED(DEFAULT_LD_Z_SEPARATE_CODE,
> $ac_default_ld_z_separate_code,
> [Define to 1 if you want to enable -z separate-code in ELF linker by default.])
>
> +if test "${ac_default_ld_z_mark_plt}" = unset; then
> + ac_default_ld_z_mark_plt=0
> +fi
> +AC_DEFINE_UNQUOTED(DEFAULT_LD_Z_MARK_PLT,
> + $ac_default_ld_z_mark_plt,
> + [Define to 1 if you want to enable -z mark-plt in ELF x86-64 linker by default.])
> +
>
> AC_DEFINE_UNQUOTED(DEFAULT_LD_WARN_EXECSTACK,
> $ac_default_ld_warn_execstack,
> diff --git a/ld/emulparams/x86-64-plt.sh b/ld/emulparams/x86-64-plt.sh
> index 92732401dc7..d1a5c65937f 100644
> --- a/ld/emulparams/x86-64-plt.sh
> +++ b/ld/emulparams/x86-64-plt.sh
> @@ -1,5 +1,10 @@
> PARSE_AND_LIST_OPTIONS_X86_64_PLT='
> - fprintf (file, _("\
> + if (DEFAULT_LD_Z_MARK_PLT != 0)
> + fprintf (file, _("\
> + -z mark-plt Mark PLT with dynamic tags (default)\n\
> + -z nomark-plt Do not mark PLT with dynamic tags\n"));
> + else
> + fprintf (file, _("\
> -z mark-plt Mark PLT with dynamic tags\n\
> -z nomark-plt Do not mark PLT with dynamic tags (default)\n"));
> '
> diff --git a/ld/emultempl/elf-x86.em b/ld/emultempl/elf-x86.em
> index 0ccad72ab9a..a6eda14253f 100644
> --- a/ld/emultempl/elf-x86.em
> +++ b/ld/emultempl/elf-x86.em
> @@ -56,3 +56,20 @@ EOF
>
> LDEMUL_BEFORE_PARSE=elf_x86_before_parse
> fi
> +
> +case x${OUTPUT_FORMAT} in
> + x*x86-64*)
> +fragment <<EOF
> +
> +static void
> +elf_x86_64_before_parse (void)
> +{
> + params.mark_plt = DEFAULT_LD_Z_MARK_PLT;
> +
> + elf_x86_before_parse ();
> +}
> +EOF
> +
> + LDEMUL_BEFORE_PARSE=elf_x86_64_before_parse
> + ;;
> +esac
> --
> 2.43.0
>
Any comments?
Thanks.
--
H.J.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2 1/2] elf: Add elf_backend_add_glibc_version_dependency
2024-01-08 15:22 ` H.J. Lu
@ 2024-01-09 13:45 ` H.J. Lu
0 siblings, 0 replies; 7+ messages in thread
From: H.J. Lu @ 2024-01-09 13:45 UTC (permalink / raw)
To: Binutils; +Cc: Alan Modra, Nick Clifton
On Mon, Jan 8, 2024 at 7:22 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Sat, Jan 6, 2024 at 2:10 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> >
> > When -z mark-plt is used to add DT_X86_64_PLT, DT_X86_64_PLTSZ and
> > DT_X86_64_PLTENT, the r_addend field of the R_X86_64_JUMP_SLOT relocation
> > stores the offset of the indirect branch instruction. However, glibc
> > versions which don't have this commit in glibc 2.36:
> >
> > commit f8587a61892cbafd98ce599131bf4f103466f084
> > Author: H.J. Lu <hjl.tools@gmail.com>
> > Date: Fri May 20 19:21:48 2022 -0700
> >
> > x86-64: Ignore r_addend for R_X86_64_GLOB_DAT/R_X86_64_JUMP_SLOT
> >
> > According to x86-64 psABI, r_addend should be ignored for R_X86_64_GLOB_DAT
> > and R_X86_64_JUMP_SLOT. Since linkers always set their r_addends to 0, we
> > can ignore their r_addends.
> >
> > Reviewed-by: Fangrui Song <maskray@google.com>
> >
> > won't ignore the r_addend value in the R_X86_64_JUMP_SLOT relocation.
> > Although this commit has been backported to glibc 2.33/2.34/2.35 release
> > branches, it is safer to require glibc 2.36 for such binaries.
> >
> > Extend the glibc version dependency of GLIBC_ABI_DT_RELR for DT_RELR to
> > also add GLIBC_2.36 version dependency for -z mark-plt on the the shared C
> > library if it provides a GLIBC_2.XX symbol version.
> >
> > * elflink.c (elf_find_verdep_info): Moved to ...
> > * elf-bfd.h (elf_find_verdep_info): Here.
> > (elf_backend_data): Add elf_backend_add_glibc_version_dependency.
> > (_bfd_elf_link_add_glibc_version_dependency): New function.
> > (_bfd_elf_link_add_dt_relr_dependency): Likewise.
> > * elf64-x86-64.c (elf_x86_64_add_glibc_version_dependency):
> > Likewise.
> > (elf_backend_add_glibc_version_dependency): New.
> > * elflink.c (elf_link_add_dt_relr_dependency): Renamed to ...
> > (elf_link_add_glibc_verneed): This. Modified to support other
> > glibc dependencies.
> > (_bfd_elf_link_add_glibc_version_dependency): Likewise.
> > (_bfd_elf_link_add_dt_relr_dependency): Likewise.
> > (bfd_elf_size_dynamic_sections): Call
> > elf_backend_add_glibc_version_dependency instead of
> > elf_link_add_dt_relr_dependency.
> > * elfxx-target.h (elf_backend_add_glibc_version_dependency): New.
> > (elfNN_bed): Add elf_backend_add_glibc_version_dependency.
> >
> > ld/
> >
> > * testsuite/ld-x86-64/mark-plt-1a.rd: New file.
> > * testsuite/ld-x86-64/mark-plt-1b.rd: Likewise.
> > * testsuite/ld-x86-64/x86-64.exp: Run -z mark-plt test for
> > GLIBC_2.36 dependency.
> > ---
> > bfd/elf-bfd.h | 23 ++++
> > bfd/elf64-x86-64.c | 27 +++++
> > bfd/elflink.c | 146 +++++++++++++++-----------
> > bfd/elfxx-target.h | 5 +
> > ld/testsuite/ld-x86-64/mark-plt-1a.rd | 7 ++
> > ld/testsuite/ld-x86-64/mark-plt-1b.rd | 7 ++
> > ld/testsuite/ld-x86-64/x86-64.exp | 14 +++
> > 7 files changed, 167 insertions(+), 62 deletions(-)
> > create mode 100644 ld/testsuite/ld-x86-64/mark-plt-1a.rd
> > create mode 100644 ld/testsuite/ld-x86-64/mark-plt-1b.rd
> >
> > diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
> > index a611349e3d9..3ed22fa6c52 100644
> > --- a/bfd/elf-bfd.h
> > +++ b/bfd/elf-bfd.h
> > @@ -957,6 +957,19 @@ typedef struct elf_property_list
> > struct elf_property property;
> > } elf_property_list;
> >
> > +/* This structure is used to pass information to
> > + elf_backend_add_glibc_version_dependency. */
> > +
> > +struct elf_find_verdep_info
> > +{
> > + /* General link information. */
> > + struct bfd_link_info *info;
> > + /* The number of dependencies. */
> > + unsigned int vers;
> > + /* Whether we had a failure. */
> > + bool failed;
> > +};
> > +
> > struct bfd_elf_section_reloc_data;
> >
> > struct elf_backend_data
> > @@ -1488,6 +1501,10 @@ struct elf_backend_data
> > bool (*elf_backend_write_section)
> > (bfd *, struct bfd_link_info *, asection *, bfd_byte *);
> >
> > + /* This function adds glibc version dependency. */
> > + void (*elf_backend_add_glibc_version_dependency)
> > + (struct elf_find_verdep_info *);
> > +
> > /* This function, if defined, returns TRUE if it is section symbols
> > only that are considered local for the purpose of partitioning the
> > symbol table into local and global symbols. This should be NULL
> > @@ -2583,6 +2600,12 @@ extern bool _bfd_elf_link_output_relocs
> > (bfd *, asection *, Elf_Internal_Shdr *, Elf_Internal_Rela *,
> > struct elf_link_hash_entry **);
> >
> > +extern void _bfd_elf_link_add_glibc_version_dependency
> > + (struct elf_find_verdep_info *, const char *[]);
> > +
> > +extern void _bfd_elf_link_add_dt_relr_dependency
> > + (struct elf_find_verdep_info *);
> > +
> > extern bool _bfd_elf_adjust_dynamic_copy
> > (struct bfd_link_info *, struct elf_link_hash_entry *, asection *);
> >
> > diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
> > index ec001599cc1..1a2e64c031f 100644
> > --- a/bfd/elf64-x86-64.c
> > +++ b/bfd/elf64-x86-64.c
> > @@ -5568,6 +5568,31 @@ elf_x86_64_link_setup_gnu_properties (struct bfd_link_info *info)
> > return _bfd_x86_elf_link_setup_gnu_properties (info, &init_table);
> > }
> >
> > +static void
> > +elf_x86_64_add_glibc_version_dependency
> > + (struct elf_find_verdep_info *rinfo)
> > +{
> > + unsigned int i = 0;
> > + const char *version[3] = { NULL, NULL, NULL };
> > + struct elf_x86_link_hash_table *htab;
> > +
> > + if (rinfo->info->enable_dt_relr)
> > + {
> > + version[i] = "GLIBC_ABI_DT_RELR";
> > + i++;
> > + }
> > +
> > + htab = elf_x86_hash_table (rinfo->info, X86_64_ELF_DATA);
> > + if (htab != NULL && htab->params->mark_plt)
> > + {
> > + version[i] = "GLIBC_2.36";
> > + i++;
> > + }
> > +
> > + if (i != 0)
> > + _bfd_elf_link_add_glibc_version_dependency (rinfo, version);
> > +}
> > +
> > static const struct bfd_elf_special_section
> > elf_x86_64_special_sections[]=
> > {
> > @@ -5652,6 +5677,8 @@ elf_x86_64_special_sections[]=
> > elf_x86_64_link_setup_gnu_properties
> > #define elf_backend_hide_symbol \
> > _bfd_x86_elf_hide_symbol
> > +#define elf_backend_add_glibc_version_dependency \
> > + elf_x86_64_add_glibc_version_dependency
> >
> > #undef elf64_bed
> > #define elf64_bed elf64_x86_64_bed
> > diff --git a/bfd/elflink.c b/bfd/elflink.c
> > index a577c957514..c2494b3e12e 100644
> > --- a/bfd/elflink.c
> > +++ b/bfd/elflink.c
> > @@ -46,19 +46,6 @@ struct elf_info_failed
> > bool failed;
> > };
> >
> > -/* This structure is used to pass information to
> > - _bfd_elf_link_find_version_dependencies. */
> > -
> > -struct elf_find_verdep_info
> > -{
> > - /* General link information. */
> > - struct bfd_link_info *info;
> > - /* The number of dependencies. */
> > - unsigned int vers;
> > - /* Whether we had a failure. */
> > - bool failed;
> > -};
> > -
> > static bool _bfd_elf_fix_symbol_flags
> > (struct elf_link_hash_entry *, struct elf_info_failed *);
> >
> > @@ -2217,64 +2204,64 @@ _bfd_elf_export_symbol (struct elf_link_hash_entry *h, void *data)
> > return true;
> > }
> >
> > -/* Return true if GLIBC_ABI_DT_RELR is added to the list of version
> > - dependencies successfully. GLIBC_ABI_DT_RELR will be put into the
> > - .gnu.version_r section. */
> > +/* Return the glibc version reference if VERSION_DEP is added to the
> > + list of glibc version dependencies successfully. VERSION_DEP will
> > + be put into the .gnu.version_r section. */
> >
> > -static bool
> > -elf_link_add_dt_relr_dependency (struct elf_find_verdep_info *rinfo)
> > +static Elf_Internal_Verneed *
> > +elf_link_add_glibc_verneed (struct elf_find_verdep_info *rinfo,
> > + Elf_Internal_Verneed *glibc_verref,
> > + const char *version_dep)
> > {
> > - bfd *glibc_bfd = NULL;
> > Elf_Internal_Verneed *t;
> > Elf_Internal_Vernaux *a;
> > size_t amt;
> > - const char *relr = "GLIBC_ABI_DT_RELR";
> >
> > - /* See if we already know about GLIBC_PRIVATE_DT_RELR. */
> > - for (t = elf_tdata (rinfo->info->output_bfd)->verref;
> > - t != NULL;
> > - t = t->vn_nextref)
> > + if (glibc_verref != NULL)
> > {
> > - const char *soname = bfd_elf_get_dt_soname (t->vn_bfd);
> > - /* Skip the shared library if it isn't libc.so. */
> > - if (!soname || !startswith (soname, "libc.so."))
> > - continue;
> > + t = glibc_verref;
> >
> > for (a = t->vn_auxptr; a != NULL; a = a->vna_nextptr)
> > {
> > - /* Return if GLIBC_PRIVATE_DT_RELR dependency has been
> > - added. */
> > - if (a->vna_nodename == relr
> > - || strcmp (a->vna_nodename, relr) == 0)
> > - return true;
> > -
> > - /* Check if libc.so provides GLIBC_2.XX version. */
> > - if (!glibc_bfd && startswith (a->vna_nodename, "GLIBC_2."))
> > - glibc_bfd = t->vn_bfd;
> > + /* Return if VERSION_DEP dependency has been added. */
> > + if (a->vna_nodename == version_dep
> > + || strcmp (a->vna_nodename, version_dep) == 0)
> > + return t;
> > }
> > -
> > - break;
> > }
> > + else
> > + {
> > + bool is_glibc;
> >
> > - /* Skip if it isn't linked against glibc. */
> > - if (glibc_bfd == NULL)
> > - return true;
> > + for (t = elf_tdata (rinfo->info->output_bfd)->verref;
> > + t != NULL;
> > + t = t->vn_nextref)
> > + {
> > + const char *soname = bfd_elf_get_dt_soname (t->vn_bfd);
> > + if (soname != NULL && startswith (soname, "libc.so."))
> > + break;
> > + }
> >
> > - /* This is a new version. Add it to tree we are building. */
> > - if (t == NULL)
> > - {
> > - amt = sizeof *t;
> > - t = (Elf_Internal_Verneed *) bfd_zalloc (rinfo->info->output_bfd,
> > - amt);
> > + /* Skip the shared library if it isn't libc.so. */
> > if (t == NULL)
> > + return t;
> > +
> > + is_glibc = false;
> > + for (a = t->vn_auxptr; a != NULL; a = a->vna_nextptr)
> > {
> > - rinfo->failed = true;
> > - return false;
> > + /* Return if VERSION_DEP dependency has been added. */
> > + if (a->vna_nodename == version_dep
> > + || strcmp (a->vna_nodename, version_dep) == 0)
> > + return t;
> > +
> > + /* Check if libc.so provides GLIBC_2.XX version. */
> > + if (!is_glibc && startswith (a->vna_nodename, "GLIBC_2."))
> > + is_glibc = true;
> > }
> >
> > - t->vn_bfd = glibc_bfd;
> > - t->vn_nextref = elf_tdata (rinfo->info->output_bfd)->verref;
> > - elf_tdata (rinfo->info->output_bfd)->verref = t;
> > + /* Skip if it isn't linked against glibc. */
> > + if (!is_glibc)
> > + return NULL;
> > }
> >
> > amt = sizeof *a;
> > @@ -2282,10 +2269,10 @@ elf_link_add_dt_relr_dependency (struct elf_find_verdep_info *rinfo)
> > if (a == NULL)
> > {
> > rinfo->failed = true;
> > - return false;
> > + return NULL;
> > }
> >
> > - a->vna_nodename = relr;
> > + a->vna_nodename = version_dep;
> > a->vna_flags = 0;
> > a->vna_nextptr = t->vn_auxptr;
> > a->vna_other = rinfo->vers + 1;
> > @@ -2293,7 +2280,45 @@ elf_link_add_dt_relr_dependency (struct elf_find_verdep_info *rinfo)
> >
> > t->vn_auxptr = a;
> >
> > - return true;
> > + return t;
> > +}
> > +
> > +/* Add VERSION_DEP to the list of version dependencies when linked
> > + against glibc. */
> > +
> > +void
> > +_bfd_elf_link_add_glibc_version_dependency
> > + (struct elf_find_verdep_info *rinfo,
> > + const char *version_dep[])
> > +{
> > + Elf_Internal_Verneed *t = NULL;
> > +
> > + do
> > + {
> > + t = elf_link_add_glibc_verneed (rinfo, t, *version_dep);
> > + /* Return if there is no glibc version reference. */
> > + if (t == NULL)
> > + return;
> > + version_dep++;
> > + }
> > + while (*version_dep != NULL);
> > +}
> > +
> > +/* Add GLIBC_ABI_DT_RELR to the list of version dependencies when
> > + linked against glibc. */
> > +
> > +void
> > +_bfd_elf_link_add_dt_relr_dependency (struct elf_find_verdep_info *rinfo)
> > +{
> > + if (rinfo->info->enable_dt_relr)
> > + {
> > + const char *version[] =
> > + {
> > + "GLIBC_ABI_DT_RELR",
> > + NULL
> > + };
> > + _bfd_elf_link_add_glibc_version_dependency (rinfo, version);
> > + }
> > }
> >
> > /* Look through the symbols which are defined in other shared
> > @@ -7047,12 +7072,9 @@ bfd_elf_size_dynamic_sections (bfd *output_bfd,
> > if (sinfo.failed)
> > return false;
> >
> > - if (info->enable_dt_relr)
> > - {
> > - elf_link_add_dt_relr_dependency (&sinfo);
> > - if (sinfo.failed)
> > - return false;
> > - }
> > + bed->elf_backend_add_glibc_version_dependency (&sinfo);
> > + if (sinfo.failed)
> > + return false;
> >
> > if (elf_tdata (output_bfd)->verref == NULL)
> > s->flags |= SEC_EXCLUDE;
> > diff --git a/bfd/elfxx-target.h b/bfd/elfxx-target.h
> > index d4b14a022e3..a7f2fc6e320 100644
> > --- a/bfd/elfxx-target.h
> > +++ b/bfd/elfxx-target.h
> > @@ -667,6 +667,10 @@
> > #ifndef elf_backend_write_section
> > #define elf_backend_write_section NULL
> > #endif
> > +#ifndef elf_backend_add_glibc_version_dependency
> > +#define elf_backend_add_glibc_version_dependency \
> > + _bfd_elf_link_add_dt_relr_dependency
> > +#endif
> > #ifndef elf_backend_elfsym_local_is_section
> > #define elf_backend_elfsym_local_is_section NULL
> > #endif
> > @@ -897,6 +901,7 @@ static const struct elf_backend_data elfNN_bed =
> > elf_backend_can_make_multiple_eh_frame,
> > elf_backend_encode_eh_address,
> > elf_backend_write_section,
> > + elf_backend_add_glibc_version_dependency,
> > elf_backend_elfsym_local_is_section,
> > elf_backend_mips_irix_compat,
> > elf_backend_mips_rtype_to_howto,
> > diff --git a/ld/testsuite/ld-x86-64/mark-plt-1a.rd b/ld/testsuite/ld-x86-64/mark-plt-1a.rd
> > new file mode 100644
> > index 00000000000..1234fbe038c
> > --- /dev/null
> > +++ b/ld/testsuite/ld-x86-64/mark-plt-1a.rd
> > @@ -0,0 +1,7 @@
> > +#...
> > +Version needs section '.gnu.version_r' contains 1 entry:
> > + Addr: 0x[0-9a-f]+ +Offset: 0x[0-9a-f]+ +Link: +[0-9]+ +\(.dynstr\)
> > + +0+: Version: 1 +File: libc\.so\.6(|\.1) +Cnt: +[0-9]+
> > +#...
> > + 0x[a-f0-9]+: Name: GLIBC_2.36 Flags: none Version: [0-9]+
> > +#pass
> > diff --git a/ld/testsuite/ld-x86-64/mark-plt-1b.rd b/ld/testsuite/ld-x86-64/mark-plt-1b.rd
> > new file mode 100644
> > index 00000000000..6556a6d939e
> > --- /dev/null
> > +++ b/ld/testsuite/ld-x86-64/mark-plt-1b.rd
> > @@ -0,0 +1,7 @@
> > +#...
> > +Version needs section '.gnu.version_r' contains 1 entry:
> > + Addr: 0x[0-9a-f]+ +Offset: 0x[0-9a-f]+ +Link: +[0-9]+ +\(.dynstr\)
> > + +0+: Version: 1 +File: libc\.so\.6(|\.1) +Cnt: +[0-9]+
> > +#...
> > + 0x[a-f0-9]+: Name: GLIBC_ABI_DT_RELR Flags: none Version: [0-9]+
> > +#pass
> > diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp
> > index 0af9f047600..d17bb9b7d7e 100644
> > --- a/ld/testsuite/ld-x86-64/x86-64.exp
> > +++ b/ld/testsuite/ld-x86-64/x86-64.exp
> > @@ -2257,4 +2257,18 @@ run_dump_test "mark-plt-1b-x32"
> > run_dump_test "mark-plt-1c-x32"
> > run_dump_test "mark-plt-1d-x32"
> >
> > +if { [check_compiler_available] } {
> > + run_cc_link_tests [list \
> > + [list \
> > + "Build mark-plt-1.so" \
> > + "-shared -Wl,-z,mark-plt,-z,pack-relative-relocs" \
> > + "-fPIC" \
> > + { mark-plt-1.s } \
> > + {{readelf {-W --version-info} mark-plt-1a.rd} \
> > + {readelf {-W --version-info} mark-plt-1b.rd}} \
> > + "mark-plt-1.so" \
> > + ] \
> > + ]
> > +}
> > +
> > set ASFLAGS "$saved_ASFLAGS"
> > --
> > 2.43.0
> >
>
> Nick, Alan,
>
> Any comments?
>
> Thanks.
>
> --
> H.J.
I will check it in later today.
--
H.J.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2 2/2] ld: Add --enable-mark-plt configure option
2024-01-08 15:24 ` H.J. Lu
@ 2024-01-09 13:46 ` H.J. Lu
0 siblings, 0 replies; 7+ messages in thread
From: H.J. Lu @ 2024-01-09 13:46 UTC (permalink / raw)
To: binutils
On Mon, Jan 8, 2024 at 7:24 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Sat, Jan 6, 2024 at 2:10 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> >
> > Add --enable-mark-plt linker configure option to mark PLT entries with
> > DT_X86_64_PLT, DT_X86_64_PLTSZ and DT_X86_64_PLTENT dynamic tags by
> > default.
> >
> > * NEWS: Mention -z mark-plt/-z nomark-plt and --enable-mark-plt.
> > * config.in: Regenerated.
> > * configure: Likewise.
> > * configure.ac: Add --enable-mark-plt.
> > (DEFAULT_LD_Z_MARK_PLT): New AC_DEFINE_UNQUOTED.
> > * emulparams/x86-64-plt.sh (PARSE_AND_LIST_OPTIONS_X86_64_PLT):
> > Support DEFAULT_LD_Z_MARK_PLT.
> > * emultempl/elf-x86.em (elf_x86_64_before_parse): New function.
> > (LDEMUL_BEFORE_PARSE): New. Set to elf_x86_64_before_parse for
> > x86-64 targets.
> > ---
> > ld/NEWS | 5 +++++
> > ld/config.in | 4 ++++
> > ld/configure | 26 ++++++++++++++++++++++++--
> > ld/configure.ac | 17 +++++++++++++++++
> > ld/emulparams/x86-64-plt.sh | 7 ++++++-
> > ld/emultempl/elf-x86.em | 17 +++++++++++++++++
> > 6 files changed, 73 insertions(+), 3 deletions(-)
> >
> > diff --git a/ld/NEWS b/ld/NEWS
> > index a2c0b7fbcfe..cedd0d72d1b 100644
> > --- a/ld/NEWS
> > +++ b/ld/NEWS
> > @@ -1,5 +1,10 @@
> > -*- text -*-
> >
> > +* Add -z mark-plt/-z nomark-plt options to x86-64 ELF linker to mark PLT
> > + entries with DT_X86_64_PLT, DT_X86_64_PLTSZ and DT_X86_64_PLTENT dynamic
> > + tags. Also added --enable-mark-plt configure option to mark PLT entries
> > + by default.
> > +
> > * Support Intel APX relocations.
> >
> > * On RISC-V, add ld target option --[no-]check-uleb128. Should rebuild the
> > diff --git a/ld/config.in b/ld/config.in
> > index 86d90d53752..52d62f06ff0 100644
> > --- a/ld/config.in
> > +++ b/ld/config.in
> > @@ -45,6 +45,10 @@
> > default. */
> > #undef DEFAULT_LD_WARN_RWX_SEGMENTS
> >
> > +/* Define to 1 if you want to enable -z mark-plt in ELF x86-64 linker by
> > + default. */
> > +#undef DEFAULT_LD_Z_MARK_PLT
> > +
> > /* Define to 1 if you want to enable -z relro in ELF linker by default. */
> > #undef DEFAULT_LD_Z_RELRO
> >
> > diff --git a/ld/configure b/ld/configure
> > index 07eb669d906..b7f29ca68b7 100755
> > --- a/ld/configure
> > +++ b/ld/configure
> > @@ -852,6 +852,7 @@ enable_new_dtags
> > enable_relro
> > enable_textrel_check
> > enable_separate_code
> > +enable_mark_plt
> > enable_warn_execstack
> > enable_error_execstack
> > enable_warn_rwx_segments
> > @@ -1546,6 +1547,7 @@ Optional Features:
> > --enable-textrel-check=[yes|no|warning|error]
> > enable DT_TEXTREL check in ELF linker
> > --enable-separate-code enable -z separate-code in ELF linker by default
> > + --enable-mark-plt enable -z mark-plt in ELF x86-64 linker by default
> > --enable-warn-execstack enable warnings when creating an executable stack
> > --enable-error-execstack
> > turn executable stack warnings into errors
> > @@ -11681,7 +11683,7 @@ else
> > lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
> > lt_status=$lt_dlunknown
> > cat > conftest.$ac_ext <<_LT_EOF
> > -#line 11684 "configure"
> > +#line 11686 "configure"
> > #include "confdefs.h"
> >
> > #if HAVE_DLFCN_H
> > @@ -11787,7 +11789,7 @@ else
> > lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
> > lt_status=$lt_dlunknown
> > cat > conftest.$ac_ext <<_LT_EOF
> > -#line 11790 "configure"
> > +#line 11792 "configure"
> > #include "confdefs.h"
> >
> > #if HAVE_DLFCN_H
> > @@ -15682,6 +15684,17 @@ esac
> > fi
> >
> >
> > +# Decide if -z mark-plt should be enabled in ELF x86-64 linker by default.
> > +ac_default_ld_z_mark_plt=unset
> > +# Check whether --enable-mark-plt was given.
> > +if test "${enable_mark_plt+set}" = set; then :
> > + enableval=$enable_mark_plt; case "${enableval}" in
> > + yes) ac_default_ld_z_mark_plt=1 ;;
> > + no) ac_default_ld_z_mark_plt=0 ;;
> > +esac
> > +fi
> > +
> > +
> >
> > # By default warn when an executable stack is created due to object files
> > # requesting such, not when the user specifies -z execstack.
> > @@ -19365,6 +19378,15 @@ cat >>confdefs.h <<_ACEOF
> > _ACEOF
> >
> >
> > +if test "${ac_default_ld_z_mark_plt}" = unset; then
> > + ac_default_ld_z_mark_plt=0
> > +fi
> > +
> > +cat >>confdefs.h <<_ACEOF
> > +#define DEFAULT_LD_Z_MARK_PLT $ac_default_ld_z_mark_plt
> > +_ACEOF
> > +
> > +
> >
> >
> > cat >>confdefs.h <<_ACEOF
> > diff --git a/ld/configure.ac b/ld/configure.ac
> > index b46f415fe9b..4a11787ae71 100644
> > --- a/ld/configure.ac
> > +++ b/ld/configure.ac
> > @@ -213,6 +213,16 @@ AC_ARG_ENABLE(separate-code,
> > no) ac_default_ld_z_separate_code=0 ;;
> > esac])
> >
> > +# Decide if -z mark-plt should be enabled in ELF x86-64 linker by default.
> > +ac_default_ld_z_mark_plt=unset
> > +AC_ARG_ENABLE(mark-plt,
> > + AS_HELP_STRING([--enable-mark-plt],
> > + [enable -z mark-plt in ELF x86-64 linker by default]),
> > +[case "${enableval}" in
> > + yes) ac_default_ld_z_mark_plt=1 ;;
> > + no) ac_default_ld_z_mark_plt=0 ;;
> > +esac])
> > +
> >
> > # By default warn when an executable stack is created due to object files
> > # requesting such, not when the user specifies -z execstack.
> > @@ -562,6 +572,13 @@ AC_DEFINE_UNQUOTED(DEFAULT_LD_Z_SEPARATE_CODE,
> > $ac_default_ld_z_separate_code,
> > [Define to 1 if you want to enable -z separate-code in ELF linker by default.])
> >
> > +if test "${ac_default_ld_z_mark_plt}" = unset; then
> > + ac_default_ld_z_mark_plt=0
> > +fi
> > +AC_DEFINE_UNQUOTED(DEFAULT_LD_Z_MARK_PLT,
> > + $ac_default_ld_z_mark_plt,
> > + [Define to 1 if you want to enable -z mark-plt in ELF x86-64 linker by default.])
> > +
> >
> > AC_DEFINE_UNQUOTED(DEFAULT_LD_WARN_EXECSTACK,
> > $ac_default_ld_warn_execstack,
> > diff --git a/ld/emulparams/x86-64-plt.sh b/ld/emulparams/x86-64-plt.sh
> > index 92732401dc7..d1a5c65937f 100644
> > --- a/ld/emulparams/x86-64-plt.sh
> > +++ b/ld/emulparams/x86-64-plt.sh
> > @@ -1,5 +1,10 @@
> > PARSE_AND_LIST_OPTIONS_X86_64_PLT='
> > - fprintf (file, _("\
> > + if (DEFAULT_LD_Z_MARK_PLT != 0)
> > + fprintf (file, _("\
> > + -z mark-plt Mark PLT with dynamic tags (default)\n\
> > + -z nomark-plt Do not mark PLT with dynamic tags\n"));
> > + else
> > + fprintf (file, _("\
> > -z mark-plt Mark PLT with dynamic tags\n\
> > -z nomark-plt Do not mark PLT with dynamic tags (default)\n"));
> > '
> > diff --git a/ld/emultempl/elf-x86.em b/ld/emultempl/elf-x86.em
> > index 0ccad72ab9a..a6eda14253f 100644
> > --- a/ld/emultempl/elf-x86.em
> > +++ b/ld/emultempl/elf-x86.em
> > @@ -56,3 +56,20 @@ EOF
> >
> > LDEMUL_BEFORE_PARSE=elf_x86_before_parse
> > fi
> > +
> > +case x${OUTPUT_FORMAT} in
> > + x*x86-64*)
> > +fragment <<EOF
> > +
> > +static void
> > +elf_x86_64_before_parse (void)
> > +{
> > + params.mark_plt = DEFAULT_LD_Z_MARK_PLT;
> > +
> > + elf_x86_before_parse ();
> > +}
> > +EOF
> > +
> > + LDEMUL_BEFORE_PARSE=elf_x86_64_before_parse
> > + ;;
> > +esac
> > --
> > 2.43.0
> >
>
> Any comments?
>
> Thanks.
>
> --
> H.J.
I will check it in later today.
--
H.J.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2024-01-09 13:46 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-01-06 22:09 [PATCH v2 0/2] Improve -z mark-plt H.J. Lu
2024-01-06 22:10 ` [PATCH v2 1/2] elf: Add elf_backend_add_glibc_version_dependency H.J. Lu
2024-01-08 15:22 ` H.J. Lu
2024-01-09 13:45 ` H.J. Lu
2024-01-06 22:10 ` [PATCH v2 2/2] ld: Add --enable-mark-plt configure option H.J. Lu
2024-01-08 15:24 ` H.J. Lu
2024-01-09 13:46 ` H.J. Lu
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