From: Will Newton <will.newton@linaro.org>
Date: Fri, 16 Aug 2013 11:54:29 +0000 (+0100)
Subject: malloc: Check for integer overflow in memalign.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4da92b3ac5974326963532aa16c4437d801a0efe;p=thirdparty%2Fglibc.git

malloc: Check for integer overflow in memalign.

A large bytes parameter to memalign 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 #15857]
	* malloc/malloc.c (__libc_memalign): Check the value of bytes
	does not overflow.

(cherry picked from commit c51d675c459aefef8d84d5a0b114010f916ea278)
---

diff --git a/malloc/malloc.c b/malloc/malloc.c
index 31e2dfad91e..ebbe86dc7c3 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -3015,6 +3015,13 @@ __libc_memalign(size_t alignment, size_t bytes)
   /* Otherwise, ensure that it is at least a minimum chunk size */
   if (alignment <  MINSIZE) alignment = MINSIZE;
 
+  /* Check for overflow.  */
+  if (bytes > SIZE_MAX - alignment - MINSIZE)
+    {
+      __set_errno (ENOMEM);
+      return 0;
+    }
+
   arena_get(ar_ptr, bytes + alignment + MINSIZE);
   if(!ar_ptr)
     return 0;