commit 41a9ed4cc88c0ed92403e1bd720c68d26c632352 Author: Ivan Maidanski <ivmai@mail.ru> Date: Thu Sep 15 18:40:21 2016 +0300 Description: Fix calloc_explicitly_typed in case of lb*n overflow Fix calloc_explicitly_typed in case of lb*n overflow (Cherry-pick commit b9d1634 from 'release-7_6' branch.) * typd_mlc.c: Include limits.h (for SIZE_MAX). * typd_mlc.c (GC_SIZE_MAX, GC_SQRT_SIZE_MAX): New macro (same as in malloc.c). * typd_mlc.c (GC_calloc_explicitly_typed): Return NULL if lb * n overflows (same algorithm as in calloc defined in malloc.c); eliminate lb *= n code duplication. Index: libgc-7.4.2/typd_mlc.c =================================================================== --- libgc-7.4.2.orig/typd_mlc.c +++ libgc-7.4.2/typd_mlc.c @@ -655,6 +655,15 @@ GC_API GC_ATTR_MALLOC void * GC_CALL return((void *) op); } +#include <limits.h> +#ifdef SIZE_MAX +# define GC_SIZE_MAX SIZE_MAX +#else +# define GC_SIZE_MAX (~(size_t)0) +#endif + +#define GC_SQRT_SIZE_MAX ((((size_t)1) << (WORDSZ / 2)) - 1) + GC_API GC_ATTR_MALLOC void * GC_CALL GC_calloc_explicitly_typed(size_t n, size_t lb, GC_descr d) { @@ -667,17 +676,20 @@ GC_API GC_ATTR_MALLOC void * GC_CALL GC_ struct LeafDescriptor leaf; DCL_LOCK_STATE; - descr_type = GC_make_array_descriptor((word)n, (word)lb, d, - &simple_descr, &complex_descr, &leaf); + descr_type = GC_make_array_descriptor((word)n, (word)lb, d, &simple_descr, + &complex_descr, &leaf); + if ((lb | n) > GC_SQRT_SIZE_MAX /* fast initial check */ + && lb > 0 && n > GC_SIZE_MAX / lb) + return NULL; /* n*lb overflow */ + lb *= n; switch(descr_type) { case NO_MEM: return(0); - case SIMPLE: return(GC_malloc_explicitly_typed(n*lb, simple_descr)); + case SIMPLE: + return GC_malloc_explicitly_typed(lb, simple_descr); case LEAF: - lb *= n; lb += sizeof(struct LeafDescriptor) + TYPD_EXTRA_BYTES; break; case COMPLEX: - lb *= n; lb += TYPD_EXTRA_BYTES; break; }