drm: Be more paranoid with integer overflows

Make sure 'width * cpp' and 'height * pitch + offset' don't exceed
UINT_MAX.

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>

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index ef1b22144d3707af9cecddee17af4d25b9b834d1..d9a639c870f43b291e76eb10287dd8617a4b98b7 100644 (file)
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -2280,13 +2280,21 @@ static int framebuffer_check(const struct drm_mode_fb_cmd2 *r)
 
        for (i = 0; i < num_planes; i++) {
                unsigned int width = r->width / (i != 0 ? hsub : 1);
+               unsigned int height = r->height / (i != 0 ? vsub : 1);
+               unsigned int cpp = drm_format_plane_cpp(r->pixel_format, i);
 
                if (!r->handles[i]) {
                        DRM_DEBUG_KMS("no buffer object handle for plane %d\n", i);
                        return -EINVAL;
                }
 
-               if (r->pitches[i] < drm_format_plane_cpp(r->pixel_format, i) * width) {
+               if ((uint64_t) width * cpp > UINT_MAX)
+                       return -ERANGE;
+
+               if ((uint64_t) height * r->pitches[i] + r->offsets[i] > UINT_MAX)
+                       return -ERANGE;
+
+               if (r->pitches[i] < width * cpp) {
                        DRM_DEBUG_KMS("bad pitch %u for plane %d\n", r->pitches[i], i);
                        return -EINVAL;
                }