https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126842
Bug ID: 126842
Summary: GCC trunk's UBSan misses null destinations in
__builtin_memcpy and __builtin_memmove
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: sanitizer
Assignee: unassigned at gcc dot gnu.org
Reporter: stuzyf at 163 dot com
CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
jakub at gcc dot gnu.org, kcc at gcc dot gnu.org
Target Milestone: ---
GCC trunk's UBSan fails to diagnose null destinations in __builtin_memcpy and
__builtin_memmove, while __builtin_memset correctly reports the error.
Reproducer: https://godbolt.org/z/jh4hcjajv
----------------------
int main ()
{
int a = 1;
char b[5];
__builtin_memcpy ((void *)0, b, sizeof (a));
// __builtin_memmove ((void *)0, b, sizeof (a));
// __builtin_memset ((void *)0, 0, sizeof (a));
return 0;
}
----------------------
With x86 GCC trunk and: -fsanitize=undefined -fno-sanitize-recover=undefined
__builtin_memcpy and __builtin_memmove do not produce a UBSan diagnostic; the
program terminates with SIGSEGV.In contrast, __builtin_memset with a null
destination correctly produces a UBSan diagnostic.
With x86 Clang and -fsanitize=undefined, __builtin_memcpy and __builtin_memmove
produce a UBSan DEADLYSIGNAL report for the null destination.
