diff options
| author | Charles Baylis <cb-kernel@fishzet.co.uk> | 2021-07-16 17:43:12 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-28 11:12:20 +0200 |
| commit | 97da260e9ef6f5359f19d81d0a1086db04091b7e (patch) | |
| tree | d3bd76017b831735ae7e21a63e5ca23faf6475b1 | |
| parent | 61b89b41bd43c76b3856113d6109139c6dbe0b7b (diff) | |
drm: Return -ENOTTY for non-drm ioctls
commit 3abab27c322e0f2acf981595aa8040c9164dc9fb upstream.
drm: Return -ENOTTY for non-drm ioctls
Return -ENOTTY from drm_ioctl() when userspace passes in a cmd number
which doesn't relate to the drm subsystem.
Glibc uses the TCGETS ioctl to implement isatty(), and without this
change isatty() returns it incorrectly returns true for drm devices.
To test run this command:
$ if [ -t 0 ]; then echo is a tty; fi < /dev/dri/card0
which shows "is a tty" without this patch.
This may also modify memory which the userspace application is not
expecting.
Signed-off-by: Charles Baylis <cb-kernel@fishzet.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/YPG3IBlzaMhfPqCr@stando.fishzet.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/gpu/drm/drm_ioctl.c | 3 | ||||
| -rw-r--r-- | include/drm/drm_ioctl.h | 1 |
2 files changed, 4 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index 60fc06234d73..ce26e8fea9c2 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -776,6 +776,9 @@ long drm_ioctl(struct file *filp, if (drm_dev_is_unplugged(dev)) return -ENODEV; + if (DRM_IOCTL_TYPE(cmd) != DRM_IOCTL_BASE) + return -ENOTTY; + is_driver_ioctl = nr >= DRM_COMMAND_BASE && nr < DRM_COMMAND_END; if (is_driver_ioctl) { diff --git a/include/drm/drm_ioctl.h b/include/drm/drm_ioctl.h index add42809642a..d9df199333fd 100644 --- a/include/drm/drm_ioctl.h +++ b/include/drm/drm_ioctl.h @@ -68,6 +68,7 @@ typedef int drm_ioctl_compat_t(struct file *filp, unsigned int cmd, unsigned long arg); #define DRM_IOCTL_NR(n) _IOC_NR(n) +#define DRM_IOCTL_TYPE(n) _IOC_TYPE(n) #define DRM_MAJOR 226 /** |