[PATCH] touch-input: Don't dereference NULL pointer during full screen fade

[Derek Foreman]

I should mention I don't have a touch capable screen and am only doing
partial testing with a modified version of libinput.  More testing would
be nice.  :)

On 29/08/14 01:12 PM, Derek Foreman wrote:
> If a full screen program is fading out and a touch start happens, it
> will result in a NULL pointer dereference when weston_touch_set_focus
> tries to derefernce view->surface->resource.
> 
> Instead, this patch sets the focus to NULL, which should be the
> same as if the program was destroyed during the touch anyway.
> 
> An additional test for NULL focus is added to prevent touch bindings
> from firing without a focus.
> 
> Closes bug 78706
> ---
>  src/input.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/src/input.c b/src/input.c
> index 975cd77..bcd603b 100644
> --- a/src/input.c
> +++ b/src/input.c
> @@ -1419,8 +1419,14 @@ weston_touch_set_focus(struct weston_seat *seat, struct weston_view *view)
>  	}
>  
>  	if (view) {
> -		struct wl_client *surface_client =
> -			wl_resource_get_client(view->surface->resource);
> +		struct wl_client *surface_client;
> +
> +		if (!view->surface->resource) {
> +			seat->touch->focus = NULL;
> +			return;
> +		}
> +
> +		surface_client = wl_resource_get_client(view->surface->resource);
>  		move_resources_for_client(focus_resource_list,
>  					  &seat->touch->resource_list,
>  					  surface_client);
> @@ -1479,8 +1485,9 @@ notify_touch(struct weston_seat *seat, uint32_t time, int touch_id,
>  			return;
>  		}
>  
> -		weston_compositor_run_touch_binding(ec, seat,
> -						    time, touch_type);
> +		if (seat->touch->focus)
> +			weston_compositor_run_touch_binding(ec, seat,
> +							    time, touch_type);
>  
>  		grab->interface->down(grab, time, touch_id, sx, sy);
>  		if (touch->num_tp == 1) {
>