[PATCH 4/7] drm: plane: Check source coordinates

[Jesse Barnes]

On Fri, 11 Nov 2011 18:04:04 +0200
ville.syrjala at linux.intel.com wrote:

> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Make sure the source coordinates stay within the buffer.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/drm_crtc.c |   23 +++++++++++++++++++++++
>  1 files changed, 23 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index 70f5747..098cc50 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -1654,6 +1654,7 @@ int drm_mode_setplane(struct drm_device *dev, void *data,
>  	struct drm_crtc *crtc;
>  	struct drm_framebuffer *fb;
>  	int ret = 0;
> +	unsigned int fb_width, fb_height;
>  
>  	if (!drm_core_check_feature(dev, DRIVER_MODESET))
>  		return -EINVAL;
> @@ -1702,6 +1703,28 @@ int drm_mode_setplane(struct drm_device *dev, void *data,
>  	}
>  	fb = obj_to_fb(obj);
>  
> +	fb_width = fb->width << 16;
> +	fb_height = fb->height << 16;
> +
> +	/* Make sure source coordinates are inside the fb. */
> +	if (plane_req->src_w > fb_width ||
> +	    plane_req->src_x > fb_width - plane_req->src_w ||
> +	    plane_req->src_h > fb_height ||
> +	    plane_req->src_y > fb_height - plane_req->src_h) {
> +		DRM_DEBUG_KMS("Invalid source coordinates "
> +			      "%01u.%06ux%01u.%06u+%01u.%06u+%01u.%06u\n",
> +			      plane_req->src_w >> 16,
> +			      ((plane_req->src_w & 0xffff) * 15625) >> 10,
> +			      plane_req->src_h >> 16,
> +			      ((plane_req->src_h & 0xffff) * 15625) >> 10,
> +			      plane_req->src_x >> 16,
> +			      ((plane_req->src_x & 0xffff) * 15625) >> 10,
> +			      plane_req->src_y >> 16,
> +			      ((plane_req->src_y & 0xffff) * 15625) >> 10);
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
>  	ret = plane->funcs->update_plane(plane, crtc, fb,
>  					 plane_req->crtc_x, plane_req->crtc_y,
>  					 plane_req->crtc_w, plane_req->crtc_h,

Good sanity check (saves the drivers from having to do it), but I
wonder if we can use a better return value like ENOSPC or something to
make it easier for userspace to figure out.

-- 
Jesse Barnes, Intel Open Source Technology Center
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