From d11ee5886e9d9ec610051a206b135a4cdc1e09a0 Mon Sep 17 00:00:00 2001
From: Thomas Hoger <thoger@redhat.com>
Date: Mon, 08 Aug 2011 16:03:09 +0000
Subject: LZW decompress: fix for CVE-2011-2895

Specially crafted LZW stream can crash an application using libXfont
that is used to open untrusted font files.  With X server, this may
allow privilege escalation when exploited

Reviewed-by: Matthieu Herrb <matthieu.herrb@laas.fr>
Signed-off-by: Matthieu Herrb <matthieu.herrb@laas.fr>
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
---
diff --git a/src/fontfile/decompress.c b/src/fontfile/decompress.c
index b1fc37b..c8171dd 100644
--- a/src/fontfile/decompress.c
+++ b/src/fontfile/decompress.c
@@ -259,6 +259,8 @@ BufCompressedFill (BufFilePtr f)
      	 */
     	while ( code >= 256 )
     	{
+	    if (stackp - de_stack >= STACK_SIZE - 1)
+		return BUFFILEEOF;
 	    *stackp++ = file->tab_suffix[code];
 	    code = file->tab_prefix[code];
     	}
--
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