[PATCH] ramdac: Check sPriv != NULL in xf86CheckHWCursor()

[walter harms]

Am 25.10.2016 00:25, schrieb Alex Goins:
> xf86CheckHWCursor() would dereference sPriv without NULL checking it. If Option
> "SWCursor" is specified, sPriv == NULL. In this case we should assume that HW
> cursors are not supported.
> 
> Signed-off-by: Alex Goins <agoins at nvidia.com>
> Reviewed-by: Andy Ritger <aritger at nvidia.com>
> ---
>  hw/xfree86/ramdac/xf86HWCurs.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/xfree86/ramdac/xf86HWCurs.c b/hw/xfree86/ramdac/xf86HWCurs.c
> index da2b181..5e99526 100644
> --- a/hw/xfree86/ramdac/xf86HWCurs.c
> +++ b/hw/xfree86/ramdac/xf86HWCurs.c
> @@ -148,7 +148,8 @@ xf86CheckHWCursor(ScreenPtr pScreen, CursorPtr cursor, xf86CursorInfoPtr infoPtr
>              continue;
>  
>          sPriv = dixLookupPrivate(&pSlave->devPrivates, xf86CursorScreenKey);
> -        if (!xf86ScreenCheckHWCursor(pSlave, cursor, sPriv->CursorInfoPtr))
> +        if (!sPriv ||
> +            !xf86ScreenCheckHWCursor(pSlave, cursor, sPriv->CursorInfoPtr))
>              return FALSE;
>      }
>      return TRUE;


I would go for 2 lines that will make things more clear also adding a comment would help
future debugging operations.

1. if (!sPriv) return FALSE;  /* maybe option "SWCursor" */

2. if (!xf86ScreenCheckHWCursor(pSlave, cursor, sPriv->CursorInfoPtr))  /* HWCursor not supported */


just my 2 cents,

re,
 wh