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| author |   Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com> | 2021-07-12 12:35:06 +0800 |
|---|---|---|
| committer |   Daniel Vetter <daniel.vetter@ffwll.ch> | 2021-07-20 20:15:20 +0200 |
| commit | 1f7ef07cfa14fb8557d1f1b7a14c76926142a4fb (patch) | |
| tree | 80f9c64f2c46217e2107a408ebf618dea7fc4772 /drivers/gpu/drm/drm_lease.c | |
| parent | drm: avoid blocking in drm_clients_info's rcu section (diff) | |
| download | linux-dev-1f7ef07cfa14fb8557d1f1b7a14c76926142a4fb.tar.xz linux-dev-1f7ef07cfa14fb8557d1f1b7a14c76926142a4fb.zip | |
drm: add a locked version of drm_is_current_master
While checking the master status of the DRM file in
drm_is_current_master(), the device's master mutex should be
held. Without the mutex, the pointer fpriv->master may be freed
concurrently by another process calling drm_setmaster_ioctl(). This
could lead to use-after-free errors when the pointer is subsequently
dereferenced in drm_lease_owner().
The callers of drm_is_current_master() from drm_auth.c hold the
device's master mutex, but external callers do not. Hence, we implement
drm_is_current_master_locked() to be used within drm_auth.c, and
modify drm_is_current_master() to grab the device's master mutex
before checking the master status.
Reported-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210712043508.11584-4-desmondcheongzx@gmail.com
Diffstat (limited to 'drivers/gpu/drm/drm_lease.c')
0 files changed, 0 insertions, 0 deletions