[PATCH] Check for NULL pointer from pixman_image_create_bits()

[Soeren Sandmann]

Bryce Harrington <bryce at canonical.com> writes:

> 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;

This patch is correct, I believe, so

Reviewed-by: Soren Sandmann <ssp at redhat.com<

However, I don't think it fixes the underlying bug since it's very
likely that pixman_image_create_bits() returned NULL because it was
passed incorrect parameters.


Soren