From baf5cc5b7a016efaa0d9bf3dfe62ad74ef4ffafe Mon Sep 17 00:00:00 2001 From: James Almer Date: Thu, 27 May 2021 11:58:57 -0300 Subject: [PATCH] avutil/mem: use GCC builtins to check for overflow in av_size_mult() Signed-off-by: James Almer --- libavutil/mem.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/libavutil/mem.h b/libavutil/mem.h index e21a1feaae..c876111afb 100644 --- a/libavutil/mem.h +++ b/libavutil/mem.h @@ -674,11 +674,18 @@ void *av_dynarray2_add(void **tab_ptr, int *nb_ptr, size_t elem_size, */ static inline int av_size_mult(size_t a, size_t b, size_t *r) { - size_t t = a * b; + size_t t; + +#if (!defined(__INTEL_COMPILER) && AV_GCC_VERSION_AT_LEAST(5,1)) || AV_HAS_BUILTIN(__builtin_mul_overflow) + if (__builtin_mul_overflow(a, b, &t)) + return AVERROR(EINVAL); +#else + t = a * b; /* Hack inspired from glibc: don't try the division if nelem and elsize * are both less than sqrt(SIZE_MAX). */ if ((a | b) >= ((size_t)1 << (sizeof(size_t) * 4)) && a && t / a != b) return AVERROR(EINVAL); +#endif *r = t; return 0; }