From e1c6431e42bc6b5619c78008cbe92730ead57bbf Mon Sep 17 00:00:00 2001 From: Nick Mathewson Date: Wed, 9 Nov 2011 12:08:28 -0500 Subject: Correct the handling of overflow behavior in smartlist_ensure_capacity The old behavior was susceptible to the compiler optimizing out our assertion check, *and* could still overflow size_t on 32-bit systems even when it did work. --- src/common/container.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) (limited to 'src/common') diff --git a/src/common/container.c b/src/common/container.c index c741eb0206..edfcd973f3 100644 --- a/src/common/container.c +++ b/src/common/container.c @@ -61,13 +61,22 @@ smartlist_clear(smartlist_t *sl) static INLINE void smartlist_ensure_capacity(smartlist_t *sl, int size) { +#if SIZEOF_SIZE_T > SIZEOF_INT +#define MAX_CAPACITY (INT_MAX) +#else +#define MAX_CAPACITY (int)((SIZE_MAX / (sizeof(void*)))) +#endif if (size > sl->capacity) { - int higher = sl->capacity * 2; - while (size > higher) - higher *= 2; - tor_assert(higher > 0); /* detect overflow */ + int higher = sl->capacity; + if (PREDICT_UNLIKELY(size > MAX_CAPACITY/2)) { + tor_assert(size <= MAX_CAPACITY); + higher = MAX_CAPACITY; + } else { + while (size > higher) + higher *= 2; + } sl->capacity = higher; - sl->list = tor_realloc(sl->list, sizeof(void*)*sl->capacity); + sl->list = tor_realloc(sl->list, sizeof(void*)*((size_t)sl->capacity)); } } -- cgit v1.2.3-54-g00ecf