diff options
| author | Duoming Zhou <duoming@zju.edu.cn> | 2025-12-17 11:00:17 +0800 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2025-12-17 10:08:44 -0800 |
| commit | bf40644ef8c8a288742fa45580897ed0e0289474 (patch) | |
| tree | 570bab7e0922f1aa9348b29ae3e018d9e3fb4928 /drivers | |
| parent | aed3716db7fff74919cc5775ca3a80c8bb246489 (diff) | |
Input: alps - fix use-after-free bugs caused by dev3_register_work
The dev3_register_work delayed work item is initialized within
alps_reconnect() and scheduled upon receipt of the first bare
PS/2 packet from an external PS/2 device connected to the ALPS
touchpad. During device detachment, the original implementation
calls flush_workqueue() in psmouse_disconnect() to ensure
completion of dev3_register_work. However, the flush_workqueue()
in psmouse_disconnect() only blocks and waits for work items that
were already queued to the workqueue prior to its invocation. Any
work items submitted after flush_workqueue() is called are not
included in the set of tasks that the flush operation awaits.
This means that after flush_workqueue() has finished executing,
the dev3_register_work could still be scheduled. Although the
psmouse state is set to PSMOUSE_CMD_MODE in psmouse_disconnect(),
the scheduling of dev3_register_work remains unaffected.
The race condition can occur as follows:
CPU 0 (cleanup path) | CPU 1 (delayed work)
psmouse_disconnect() |
psmouse_set_state() |
flush_workqueue() | alps_report_bare_ps2_packet()
alps_disconnect() | psmouse_queue_work()
kfree(priv); // FREE | alps_register_bare_ps2_mouse()
| priv = container_of(work...); // USE
| priv->dev3 // USE
Add disable_delayed_work_sync() in alps_disconnect() to ensure
that dev3_register_work is properly canceled and prevented from
executing after the alps_data structure has been deallocated.
This bug is identified by static analysis.
Fixes: 04aae283ba6a ("Input: ALPS - do not mix trackstick and external PS/2 mouse data")
Cc: stable@kernel.org
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Link: https://patch.msgid.link/b57b0a9ccca51a3f06be141bfc02b9ffe69d1845.1765939397.git.duoming@zju.edu.cn
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/input/mouse/alps.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c index d0cb9fb94821..df8953a5196e 100644 --- a/drivers/input/mouse/alps.c +++ b/drivers/input/mouse/alps.c @@ -2975,6 +2975,7 @@ static void alps_disconnect(struct psmouse *psmouse) psmouse_reset(psmouse); timer_shutdown_sync(&priv->timer); + disable_delayed_work_sync(&priv->dev3_register_work); if (priv->dev2) input_unregister_device(priv->dev2); if (!IS_ERR_OR_NULL(priv->dev3)) |