[PATCH] Check for NULL pointer from pixman_image_create_bits()

[Bryce Harrington]

pixman_image_create_bits() can return NULL under a variety of
circumstances.  If this happens, it will segfault when dereferenced in
pixman_image_set_accessors().

http://bugs.freedesktop.org/show_bug.cgi?id=28882
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=596155
https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/705078

Signed-off-by: Bryce Harrington <bryce at canonical.com>
---
 fb/fbpict.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/fb/fbpict.c b/fb/fbpict.c
index 7636040..79b462b 100644
--- a/fb/fbpict.c
+++ b/fb/fbpict.c
@@ -163,7 +163,8 @@ create_bits_picture (PicturePtr pict,
 	pict->format,
 	pixmap->drawable.width, pixmap->drawable.height,
 	(uint32_t *)bits, stride * sizeof (FbStride));
-    
+    if (!image)
+        return NULL;
     
 #ifdef FB_ACCESS_WRAPPER
 #if FB_SHIFT==5
-- 
1.7.1