From 5216c93baebfa4e129ea1fc6fffd2c842aaea839 Mon Sep 17 00:00:00 2001 From: Alexander Kuleshov Date: Tue, 16 Feb 2016 23:51:43 +0600 Subject: [PATCH] alloc-util: cleanups This patch contains a set of little cleanups for alloc-util.h: 1. The malloc_multiply(), realloc_multiply() and memdup_multiply() functions check allocation related parameters on overflow. Let's move them to the separate size_multiply_overflow() function for simplicity, code duplication prevention and possible reuse in future. 2. use SIZE_MAX from stdlib instead of ((size_t) - 1) to be more clear. 3. The 'a'/'b' variables are renamed to 'size' and 'need' to be more clear.' --- src/basic/alloc-util.h | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/src/basic/alloc-util.h b/src/basic/alloc-util.h index 679ba7f39..ceeee519b 100644 --- a/src/basic/alloc-util.h +++ b/src/basic/alloc-util.h @@ -51,25 +51,29 @@ static inline void freep(void *p) { #define _cleanup_free_ _cleanup_(freep) -_malloc_ _alloc_(1, 2) static inline void *malloc_multiply(size_t a, size_t b) { - if (_unlikely_(b != 0 && a > ((size_t) -1) / b)) +static inline bool size_multiply_overflow(size_t size, size_t need) { + return _unlikely_(need != 0 && size > (SIZE_MAX / need)); +} + +_malloc_ _alloc_(1, 2) static inline void *malloc_multiply(size_t size, size_t need) { + if (size_multiply_overflow(size, need)) return NULL; - return malloc(a * b); + return malloc(size * need); } -_alloc_(2, 3) static inline void *realloc_multiply(void *p, size_t a, size_t b) { - if (_unlikely_(b != 0 && a > ((size_t) -1) / b)) +_alloc_(2, 3) static inline void *realloc_multiply(void *p, size_t size, size_t need) { + if (size_multiply_overflow(size, need)) return NULL; - return realloc(p, a * b); + return realloc(p, size * need); } -_alloc_(2, 3) static inline void *memdup_multiply(const void *p, size_t a, size_t b) { - if (_unlikely_(b != 0 && a > ((size_t) -1) / b)) +_alloc_(2, 3) static inline void *memdup_multiply(const void *p, size_t size, size_t need) { + if (size_multiply_overflow(size, need)) return NULL; - return memdup(p, a * b); + return memdup(p, size * need); } void* greedy_realloc(void **p, size_t *allocated, size_t need, size_t size); -- 2.30.2