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From: Will Newton <will.newton@linaro.org>
Date: Mon, 12 Aug 2013 15:08:02 +0100
Subject: [PATCH] malloc: Check for integer overflow in pvalloc.
A large bytes parameter to pvalloc could cause an integer overflow
and corrupt allocator internals. Check the overflow does not occur
before continuing with the allocation.
ChangeLog:
2013-09-11 Will Newton <will.newton@linaro.org>
[BZ #15855]
* malloc/malloc.c (__libc_pvalloc): Check the value of bytes
does not overflow.
---
malloc/malloc.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/malloc/malloc.c b/malloc/malloc.c
index be472b2..bcc08c4 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -3082,6 +3082,13 @@ __libc_pvalloc(size_t bytes)
size_t page_mask = GLRO(dl_pagesize) - 1;
size_t rounded_bytes = (bytes + page_mask) & ~(page_mask);
+ /* Check for overflow. */
+ if (bytes > SIZE_MAX - 2*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))
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