From e0e11644622a589129a01e11e5d105dc74a098de Mon Sep 17 00:00:00 2001
From: Alan Coopersmith <alan.coopersmith@oracle.com>
Date: Wed, 22 Jan 2014 23:44:46 -0800
Subject: [PATCH] dix: integer overflow in REQUEST_FIXED_SIZE() [CVE-2014-8092
 4/4]

Force use of 64-bit integers when evaluating data provided by clients
in 32-bit fields which can overflow when added or multiplied during
checks.

Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
---
 include/dix.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/dix.h b/include/dix.h
index 991a3ce88..e0c6ed84f 100644
--- a/include/dix.h
+++ b/include/dix.h
@@ -76,7 +76,8 @@ SOFTWARE.
 
 #define REQUEST_FIXED_SIZE(req, n)\
     if (((sizeof(req) >> 2) > client->req_len) || \
-        (((sizeof(req) + (n) + 3) >> 2) != client->req_len)) \
+        ((n >> 2) >= client->req_len) || \
+        ((((uint64_t) sizeof(req) + (n) + 3) >> 2) != (uint64_t) client->req_len))  \
          return(BadLength)
 
 #define LEGAL_NEW_RESOURCE(id,client)\