drm/amd/display: Validate plane rects before use

[Why]
Calculation of scaling ratio can result in a crash due to zero'd src or
dst plane rects.

[How]
Validate that src and dst rects are valid before using for scaling
calculations.
Reviewed-by: Josip Pavic <Josip.Pavic@amd.com>
Acked-by: Agustin Gutierrez Sanchez <agustin.gutierrez@amd.com>
Signed-off-by: Aric Cyr <aric.cyr@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc_resource.c

@@ -3009,6 +3009,11 @@ enum dc_status dc_validate_plane(struct dc *dc, const struct dc_plane_state *pla
 {
 	enum dc_status res = DC_OK;
 
+	/* check if surface has invalid dimensions */
+	if (plane_state->src_rect.width == 0 || plane_state->src_rect.height == 0 ||
+		plane_state->dst_rect.width == 0 || plane_state->dst_rect.height == 0)
+		return DC_FAIL_SURFACE_VALIDATE;
+
 	/* TODO For now validates pixel format only */
 	if (dc->res_pool->funcs->validate_plane)
 		return dc->res_pool->funcs->validate_plane(plane_state, &dc->caps);