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[PATCH v3] [BZ #15856] malloc: Check for integer overflow in valloc.
- From: Will Newton <will dot newton at linaro dot org>
- To: libc-ports at sourceware dot org
- Cc: patches at linaro dot org
- Date: Tue, 10 Sep 2013 14:16:29 +0100
- Subject: [PATCH v3] [BZ #15856] malloc: Check for integer overflow in valloc.
- Authentication-results: sourceware.org; auth=none
A large bytes parameter to valloc could cause an integer overflow
and corrupt allocator internals. Check the overflow does not occur
before continuing with the allocation.
ChangeLog:
2013-08-16 Will Newton <will.newton@linaro.org>
[BZ #15856]
* malloc/malloc.c (__libc_valloc): Check the value of bytes
does not overflow.
---
malloc/malloc.c | 7 +++++++
1 file changed, 7 insertions(+)
Changes in v3:
- Reorder if condition
- Set errno appropriately
diff --git a/malloc/malloc.c b/malloc/malloc.c
index 7f43ba3..3148c5f 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -3046,6 +3046,13 @@ __libc_valloc(size_t bytes)
size_t pagesz = GLRO(dl_pagesize);
+ /* Check for overflow. */
+ if (bytes > SIZE_MAX - pagesz - MINSIZE)
+ {
+ __set_errno (ENOMEM);
+ return 0;
+ }
+
void *(*hook) (size_t, size_t, const void *) =
force_reg (__memalign_hook);
if (__builtin_expect (hook != NULL, 0))
--
1.8.1.4