[PATCH] drm: Reject unknown legacy bpp and dpeth for drm_mode_addfb ioctl

Chris Wilson
2018-09-04T20:53:19Z

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.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
So I am presuming that r.pixel_format == 0 is rejected elsewhere for the
internal users (as if any would deliberately provoke the error)!
---
drivers/gpu/drm/drm_fourcc.c | 4 ++--
drivers/gpu/drm/drm_framebuffer.c | 5 ++++-
2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
index 35c1e2742c27..34595c5b55c9 100644
--- a/drivers/gpu/drm/drm_fourcc.c
+++ b/drivers/gpu/drm/drm_fourcc.c
@@ -69,8 +69,8 @@ uint32_t drm_mode_legacy_fb_format(uint32_t bpp, uint32_t depth)
fmt = DRM_FORMAT_ARGB8888;
break;
default:
- DRM_ERROR("bad bpp, assuming x8r8g8b8 pixel format\n");
- fmt = DRM_FORMAT_XRGB8888;
+ DRM_DEBUG("bad bpp [%d] and depth [%d]\n", bpp, depth);
+ fmt = 0;
break;
}

diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
index 781af1d42d76..7641bddfe367 100644
--- a/drivers/gpu/drm/drm_framebuffer.c
+++ b/drivers/gpu/drm/drm_framebuffer.c
@@ -112,12 +112,15 @@ 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)
+ 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 (r.pixel_format == DRM_FORMAT_XRGB2101010 &&
--
2.19.0.rc1