drm: Check crtc x and y coordinates

commit 1d97e9154821d52a5ebc226176d4839c7b86b116 upstream.

The crtc x/y panning coordinates are stored as signed integers
internally. The user provides them as unsigned, so we should check
that the user provided values actually fit in the internal datatypes.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 09851ce..0e716fd 100644 (file)
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -1505,6 +1505,10 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
        if (!drm_core_check_feature(dev, DRIVER_MODESET))
                return -EINVAL;
 
+       /* For some reason crtc x/y offsets are signed internally. */
+       if (crtc_req->x > INT_MAX || crtc_req->y > INT_MAX)
+               return -ERANGE;
+
        mutex_lock(&dev->mode_config.mutex);
        obj = drm_mode_object_find(dev, crtc_req->crtc_id,
                                   DRM_MODE_OBJECT_CRTC);