* [PATCH] ssp: add support for _FORTIFY_SOURCE=3
@ 2024-01-26 16:29 Christian Franke
2024-01-29 15:29 ` Corinna Vinschen
0 siblings, 1 reply; 2+ messages in thread
From: Christian Franke @ 2024-01-26 16:29 UTC (permalink / raw)
To: newlib
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_FORTIFY_SOURCE=3 is already supported by glibc and MinGW-w64 headers.
Tested on Cygwin with current gcc 13.2.1 test release.
--
Regards,
Christian
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From 95bd8aadf02ee95bbc9a05f37e88c78430027733 Mon Sep 17 00:00:00 2001
From: Christian Franke <christian.franke@t-online.de>
Date: Fri, 26 Jan 2024 17:20:37 +0100
Subject: [PATCH] ssp: add support for _FORTIFY_SOURCE=3
If specified, use __builtin_dynamic_object_size() instead of
__builtin_object_size() if supported (GCC 12.0 or later).
This enables buffer overflow checks if the buffer size is non-const
but known during runtime.
Use new macro __ssp_bos_known() instead of the (bos(p) != (size_t)-1)
checks. The latter is no longer a compile time constant in all cases.
This avoids the generation of unused code.
Signed-off-by: Christian Franke <christian.franke@t-online.de>
---
newlib/libc/include/ssp/ssp.h | 11 ++++++++++-
newlib/libc/include/ssp/string.h | 4 ++--
newlib/libc/include/ssp/strings.h | 4 ++--
newlib/libc/include/sys/features.h | 12 +++++++++---
4 files changed, 23 insertions(+), 8 deletions(-)
diff --git a/newlib/libc/include/ssp/ssp.h b/newlib/libc/include/ssp/ssp.h
index 922908659..49ea5f2dd 100644
--- a/newlib/libc/include/ssp/ssp.h
+++ b/newlib/libc/include/ssp/ssp.h
@@ -43,11 +43,20 @@
#define __ssp_inline extern __inline__ __attribute__((__always_inline__, __gnu_inline__))
+#if __SSP_FORTIFY_LEVEL > 2
+#define __ssp_bos(ptr) __builtin_dynamic_object_size(ptr, 1)
+#define __ssp_bos0(ptr) __builtin_dynamic_object_size(ptr, 0)
+#define __ssp_bos_known(ptr) \
+ (__builtin_object_size(ptr, 0) != (size_t)-1 \
+ || !__builtin_constant_p(__ssp_bos(ptr)))
+#else
#define __ssp_bos(ptr) __builtin_object_size(ptr, __SSP_FORTIFY_LEVEL > 1)
#define __ssp_bos0(ptr) __builtin_object_size(ptr, 0)
+#define __ssp_bos_known(ptr) (__ssp_bos0(ptr) != (size_t)-1)
+#endif
#define __ssp_check(buf, len, bos) \
- if (bos(buf) != (size_t)-1 && len > bos(buf)) \
+ if (__ssp_bos_known(buf) && len > bos(buf)) \
__chk_fail()
#define __ssp_decl(rtype, fun, args) \
rtype __ssp_real_(fun) args __asm__(__ASMNAME(#fun)); \
diff --git a/newlib/libc/include/ssp/string.h b/newlib/libc/include/ssp/string.h
index 85c4512ac..22b52097c 100644
--- a/newlib/libc/include/ssp/string.h
+++ b/newlib/libc/include/ssp/string.h
@@ -49,12 +49,12 @@ __END_DECLS
#if __SSP_FORTIFY_LEVEL > 0
#define __ssp_bos_check3(fun, dst, src, len) \
- ((__ssp_bos0(dst) != (size_t)-1) ? \
+ (__ssp_bos_known(dst) ? \
__builtin___ ## fun ## _chk(dst, src, len, __ssp_bos0(dst)) : \
__ ## fun ## _ichk(dst, src, len))
#define __ssp_bos_check2(fun, dst, src) \
- ((__ssp_bos0(dst) != (size_t)-1) ? \
+ (__ssp_bos_known(dst) ? \
__builtin___ ## fun ## _chk(dst, src, __ssp_bos0(dst)) : \
__ ## fun ## _ichk(dst, src))
diff --git a/newlib/libc/include/ssp/strings.h b/newlib/libc/include/ssp/strings.h
index 13adba175..be59882eb 100644
--- a/newlib/libc/include/ssp/strings.h
+++ b/newlib/libc/include/ssp/strings.h
@@ -37,11 +37,11 @@
#if __BSD_VISIBLE || __POSIX_VISIBLE <= 200112
#define bcopy(src, dst, len) \
- ((__ssp_bos0(dst) != (size_t)-1) ? \
+ (__ssp_bos_known(dst) ? \
__builtin___memmove_chk(dst, src, len, __ssp_bos0(dst)) : \
__memmove_ichk(dst, src, len))
#define bzero(dst, len) \
- ((__ssp_bos0(dst) != (size_t)-1) ? \
+ (__ssp_bos_known(dst) ? \
__builtin___memset_chk(dst, 0, len, __ssp_bos0(dst)) : \
__memset_ichk(dst, 0, len))
#endif
diff --git a/newlib/libc/include/sys/features.h b/newlib/libc/include/sys/features.h
index a7d4bc52d..6a925c87e 100644
--- a/newlib/libc/include/sys/features.h
+++ b/newlib/libc/include/sys/features.h
@@ -104,7 +104,7 @@ extern "C" {
* _DEFAULT_SOURCE (or none of the above)
* POSIX-1.2008 with BSD and SVr4 extensions
*
- * _FORTIFY_SOURCE = 1 or 2
+ * _FORTIFY_SOURCE = 1, 2 or 3
* Object Size Checking function wrappers
*/
@@ -247,7 +247,7 @@ extern "C" {
* GNU extensions; enabled with _GNU_SOURCE.
*
* __SSP_FORTIFY_LEVEL
- * Object Size Checking; defined to 0 (off), 1, or 2.
+ * Object Size Checking; defined to 0 (off), 1, 2 or 3.
*
* In all cases above, "enabled by default" means either by defining
* _DEFAULT_SOURCE, or by not defining any of the public feature test macros.
@@ -335,7 +335,13 @@ extern "C" {
#if _FORTIFY_SOURCE > 0 && !defined(__cplusplus) && !defined(__lint__) && \
(__OPTIMIZE__ > 0 || defined(__clang__)) && __GNUC_PREREQ__(4, 1) && \
!defined(_LIBC)
-# if _FORTIFY_SOURCE > 1
+# if _FORTIFY_SOURCE > 2 && defined(__has_builtin)
+# if __has_builtin(__builtin_dynamic_object_size)
+# define __SSP_FORTIFY_LEVEL 3
+# else
+# define __SSP_FORTIFY_LEVEL 2
+# endif
+# elif _FORTIFY_SOURCE > 1
# define __SSP_FORTIFY_LEVEL 2
# else
# define __SSP_FORTIFY_LEVEL 1
--
2.43.0
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] ssp: add support for _FORTIFY_SOURCE=3
2024-01-26 16:29 [PATCH] ssp: add support for _FORTIFY_SOURCE=3 Christian Franke
@ 2024-01-29 15:29 ` Corinna Vinschen
0 siblings, 0 replies; 2+ messages in thread
From: Corinna Vinschen @ 2024-01-29 15:29 UTC (permalink / raw)
To: Christian Franke; +Cc: newlib
On Jan 26 17:29, Christian Franke wrote:
> _FORTIFY_SOURCE=3 is already supported by glibc and MinGW-w64 headers.
>
> Tested on Cygwin with current gcc 13.2.1 test release.
Pushed.
Thanks,
Corinna
^ permalink raw reply [flat|nested] 2+ messages in thread
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