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* [gcc r11-11351] ubsan: Don't -fsanitize=null instrument __seg_fs/gs pointers [PR111736]
@ 2024-04-24 14:39 Uros Bizjak
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From: Uros Bizjak @ 2024-04-24 14:39 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:624c3bb9ff762f196852dc77233610d1cdf7d7be
commit r11-11351-g624c3bb9ff762f196852dc77233610d1cdf7d7be
Author: Jakub Jelinek <jakub@redhat.com>
Date: Fri Mar 22 09:23:44 2024 +0100
ubsan: Don't -fsanitize=null instrument __seg_fs/gs pointers [PR111736]
On x86 and avr some address spaces allow 0 pointers (on avr actually
even generic as, but libsanitizer isn't ported to it and
I'm not convinced we should completely kill -fsanitize=null in that
case).
The following patch makes sure those aren't diagnosed for -fsanitize=null,
though they are still sanitized for -fsanitize=alignment.
2024-03-22 Jakub Jelinek <jakub@redhat.com>
gcc/ChangeLog:
PR sanitizer/111736
* ubsan.c (ubsan_expand_null_ifn, instrument_mem_ref): Avoid
SANITIZE_NULL instrumentation for non-generic address spaces
for which targetm.addr_space.zero_address_valid (as) is true.
gcc/testsuite/ChangeLog:
* gcc.dg/ubsan/pr111736.c: New test.
(cherry picked from commit ddd4a3ca87410886b039cc225907b4f6e650082e)
Diff:
---
gcc/testsuite/gcc.dg/ubsan/pr111736.c | 23 +++++++++++++++++++++++
gcc/ubsan.c | 19 +++++++++++++++++--
2 files changed, 40 insertions(+), 2 deletions(-)
diff --git a/gcc/testsuite/gcc.dg/ubsan/pr111736.c b/gcc/testsuite/gcc.dg/ubsan/pr111736.c
new file mode 100644
index 00000000000..359b31828f0
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/ubsan/pr111736.c
@@ -0,0 +1,23 @@
+/* PR sanitizer/111736 */
+/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
+/* { dg-options "-fsanitize=null,alignment -fdump-tree-optimized -ffat-lto-objects" } */
+/* { dg-final { scan-tree-dump-times "__ubsan_handle_type_mismatch" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-not "p_\[0-9]*.D. \[=!]= 0" "optimized" } } */
+
+#ifdef __x86_64__
+#define SEG __seg_fs
+#else
+#define SEG __seg_gs
+#endif
+
+int
+foo (int SEG *p, int *q)
+{
+ return *p;
+}
+
+__attribute__((no_sanitize("alignment"))) int
+bar (int SEG *p, int *q)
+{
+ return *p;
+}
diff --git a/gcc/ubsan.c b/gcc/ubsan.c
index 04e8c1552a7..2b12651b440 100644
--- a/gcc/ubsan.c
+++ b/gcc/ubsan.c
@@ -49,6 +49,7 @@ along with GCC; see the file COPYING3. If not see
#include "tree-cfg.h"
#include "gimple-fold.h"
#include "varasm.h"
+#include "target.h"
/* Map from a tree to a VAR_DECL tree. */
@@ -784,6 +785,13 @@ ubsan_expand_null_ifn (gimple_stmt_iterator *gsip)
}
}
check_null = sanitize_flags_p (SANITIZE_NULL);
+ if (check_null && POINTER_TYPE_P (TREE_TYPE (ptr)))
+ {
+ addr_space_t as = TYPE_ADDR_SPACE (TREE_TYPE (TREE_TYPE (ptr)));
+ if (!ADDR_SPACE_GENERIC_P (as)
+ && targetm.addr_space.zero_address_valid (as))
+ check_null = false;
+ }
if (check_align == NULL_TREE && !check_null)
{
@@ -1375,8 +1383,15 @@ instrument_mem_ref (tree mem, tree base, gimple_stmt_iterator *iter,
if (align <= 1)
align = 0;
}
- if (align == 0 && !sanitize_flags_p (SANITIZE_NULL))
- return;
+ if (align == 0)
+ {
+ if (!sanitize_flags_p (SANITIZE_NULL))
+ return;
+ addr_space_t as = TYPE_ADDR_SPACE (TREE_TYPE (base));
+ if (!ADDR_SPACE_GENERIC_P (as)
+ && targetm.addr_space.zero_address_valid (as))
+ return;
+ }
tree t = TREE_OPERAND (base, 0);
if (!POINTER_TYPE_P (TREE_TYPE (t)))
return;
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2024-04-24 14:39 [gcc r11-11351] ubsan: Don't -fsanitize=null instrument __seg_fs/gs pointers [PR111736] Uros Bizjak
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