From dbacacaaeac47f792fb33ead7f8946689219ef2c 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 | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/src/basic/alloc-util.h b/src/basic/alloc-util.h index 679ba7f398..ceeee519b7 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)) - return NULL; - - return malloc(a * b); +static inline bool size_multiply_overflow(size_t size, size_t need) { + return _unlikely_(need != 0 && size > (SIZE_MAX / 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)) +_malloc_ _alloc_(1, 2) static inline void *malloc_multiply(size_t size, size_t need) { + if (size_multiply_overflow(size, need)) return NULL; - return realloc(p, a * b); + return malloc(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 *realloc_multiply(void *p, size_t size, size_t need) { + if (size_multiply_overflow(size, need)) return NULL; - return memdup(p, a * b); + return realloc(p, size * need); +} + +_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, size * need); } void* greedy_realloc(void **p, size_t *allocated, size_t need, size_t size);