[Spice-devel] [PATCH] server/red_parse_qxl: disallow zero area bitmaps

[Alon Levy]

On Fri, Jul 20, 2012 at 07:41:01PM +0300, Alon Levy wrote:
> prevents division by zero later (SIGFPE, Arithmetic exception) in
> spice-common code, at spice-common/common/canvas_base.c:646
> for both client and server (server only upon rendering).
> ---
>  server/red_parse_qxl.c |    4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/server/red_parse_qxl.c b/server/red_parse_qxl.c
> index daae897..7de21e4 100644
> --- a/server/red_parse_qxl.c
> +++ b/server/red_parse_qxl.c
> @@ -371,6 +371,10 @@ static SpiceImage *red_get_image(RedMemSlotInfo *slots, int group_id,
>                            red->u.bitmap.format);
>              return NULL;
>          }
> +        if (qxl->bitmap.x == 0 && qxl->bitmap.y == 0) {

This should of course be ||

> +            spice_warning("guest error: zero area bitmap\n");
> +            return NULL;
> +        }
>          qxl_flags = qxl->bitmap.flags;
>          if (qxl_flags & QXL_BITMAP_TOP_DOWN) {
>              red->u.bitmap.flags = SPICE_BITMAP_FLAGS_TOP_DOWN;
> -- 
> 1.7.10.1
> 
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