From: Will Newton <will.newton@linaro.org>
Date: Fri, 16 Aug 2013 11:59:37 +0100
Subject: [PATCH] malloc: Check for integer overflow in valloc.

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:

2013-09-11  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(+)

diff --git a/malloc/malloc.c b/malloc/malloc.c
index bcc08c4..31e2dfa 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))