drm: use drms ioctl cmd not what we get passed from userspace.
This enforces us to use the drm ioctl types so read/write works correctly and not believe
what userspace tells us.
It does this hopefully without breaking the drm api.
Fixes bug from thread: BUG: unable to handle kernel NULL pointer dereference (drm_getunique)
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/char/drm/drm_drv.c b/drivers/char/drm/drm_drv.c
index fc54140..22957ac1 100644
--- a/drivers/char/drm/drm_drv.c
+++ b/drivers/char/drm/drm_drv.c
@@ -475,6 +475,8 @@
else
goto err_i1;
+ /* Do not trust userspace, use our own definition */
+ cmd = ioctl->cmd;
func = ioctl->func;
/* is there a local override? */
if ((nr == DRM_IOCTL_NR(DRM_IOCTL_DMA)) && dev->driver->dma_ioctl)