Here's a patch that bypasses the INT32_MAX check, allowing zero-height PutImage requests.
From 6dc2634aee9023ac9d20dc06a76d9fa1f03ff2cd Mon Sep 17 00:00:00 2001
From: Keith Packard <keithp@keithp.com>
Date: Sat, 3 Jan 2015 08:46:45 -0800
Subject: [PATCH] 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>
---
dix/dispatch.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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) +
--
2.1.4
-- -keith
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