From b4b1e10364c8737a632be61582e05a8d3acf5690 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Thu, 19 Apr 2018 22:19:29 -0400 Subject: reintroduce hardening against partially-replaced allocator commit 618b18c78e33acfe54a4434e91aa57b8e171df89 removed the previous detection and hardening since it was incorrect. commit 72141795d4edd17f88da192447395a48444afa10 already handled all that remained for hardening the static-linked case. in the dynamic-linked case, have the dynamic linker check whether malloc was replaced and make that information available. with these changes, the properties documented in commit c9f415d7ea2dace5bf77f6518b6afc36bb7a5732 are restored: if calloc is not provided, it will behave as malloc+memset, and any of the memalign-family functions not provided will fail with ENOMEM. --- src/malloc/malloc.c | 13 +++++++++---- src/malloc/memalign.c | 2 +- 2 files changed, 10 insertions(+), 5 deletions(-) (limited to 'src/malloc') diff --git a/src/malloc/malloc.c b/src/malloc/malloc.c index 239ab9c6..d72883e1 100644 --- a/src/malloc/malloc.c +++ b/src/malloc/malloc.c @@ -20,6 +20,8 @@ static struct { volatile int free_lock[2]; } mal; +int __malloc_replaced; + /* Synchronization tools */ static inline void lock(volatile int *lk) @@ -356,10 +358,13 @@ void *calloc(size_t m, size_t n) } n *= m; void *p = malloc(n); - if (!p || IS_MMAPPED(MEM_TO_CHUNK(p))) - return p; - if (n >= PAGE_SIZE) - n = mal0_clear(p, PAGE_SIZE, n); + if (!p) return p; + if (!__malloc_replaced) { + if (IS_MMAPPED(MEM_TO_CHUNK(p))) + return p; + if (n >= PAGE_SIZE) + n = mal0_clear(p, PAGE_SIZE, n); + } return memset(p, 0, n); } diff --git a/src/malloc/memalign.c b/src/malloc/memalign.c index 7246a99b..8a6152f4 100644 --- a/src/malloc/memalign.c +++ b/src/malloc/memalign.c @@ -13,7 +13,7 @@ void *__memalign(size_t align, size_t len) return 0; } - if (len > SIZE_MAX - align) { + if (len > SIZE_MAX - align || __malloc_replaced) { errno = ENOMEM; return 0; } -- cgit v1.2.1