From dc777c346d5d452a53b13b917c45f6a1bad2f20b Mon Sep 17 00:00:00 2001
From: Keith Packard <keithp@keithp.com>
Date: Sat, 3 Jan 2015 08:46:45 -0800
Subject: dix: Allow zero-height PutImage requests

The length checking code validates PutImage height and byte width by
making sure that byte-width >= INT32_MAX / height. If height is zero,
this generates a divide by zero exception. Allow zero height requests
explicitly, bypassing the INT32_MAX check.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Alan Coopersmith <alan.coopersmith@oracle.com>

diff --git a/dix/dispatch.c b/dix/dispatch.c
index 55b978d..9044ac7 100644
--- a/dix/dispatch.c
+++ b/dix/dispatch.c
@@ -2000,7 +2000,7 @@ ProcPutImage(ClientPtr client)
     tmpImage = (char *) &stuff[1];
     lengthProto = length;
 
-    if (lengthProto >= (INT32_MAX / stuff->height))
+    if (stuff->height != 0 && lengthProto >= (INT32_MAX / stuff->height))
         return BadLength;
 
     if ((bytes_to_int32(lengthProto * stuff->height) +
-- 
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