drm: Reject unknown legacy bpp and depth for drm_mode_addfb ioctl

Since this is handling user provided bpp and depth, we need to sanity
check and propagate the EINVAL back rather than assume what the insane
client intended and fill the logs with DRM_ERROR.

v2: Check both bpp and depth match the builtin pixel format, and
introduce a canonical DRM_FORMAT_INVALID to reserve 0 against any future
fourcc.

v3: Mark up DRM_FORMAT_C8 as being {bpp:8, depth:8}

Testcase: igt/kms_addfb_basic/legacy-format
Signed-off-by: Chris Wilson <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Ville Syrjälä <[email protected]>
Cc: Michel Dänzer <[email protected]>
Reviewed-by: Daniel Vetter <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
index f863f8a20f8c..c8a7829d73d6 100644
--- a/drivers/gpu/drm/drm_framebuffer.c
+++ b/drivers/gpu/drm/drm_framebuffer.c
@@ -112,12 +112,17 @@ int drm_mode_addfb(struct drm_device *dev, struct drm_mode_fb_cmd *or,
 	struct drm_mode_fb_cmd2 r = {};
 	int ret;
 
+	r.pixel_format = drm_mode_legacy_fb_format(or->bpp, or->depth);
+	if (r.pixel_format == DRM_FORMAT_INVALID) {
+		DRM_DEBUG("bad {bpp:%d, depth:%d}\n", or->bpp, or->depth);
+		return -EINVAL;
+	}
+
 	/* convert to new format and call new ioctl */
 	r.fb_id = or->fb_id;
 	r.width = or->width;
 	r.height = or->height;
 	r.pitches[0] = or->pitch;
-	r.pixel_format = drm_mode_legacy_fb_format(or->bpp, or->depth);
 	r.handles[0] = or->handle;
 
 	if (dev->mode_config.quirk_addfb_prefer_xbgr_30bpp &&