lkkbd_interrupt() schedules lk->tq with schedule_work(), and the work handler lkkbd_reinit() dereferences the lkkbd structure and its serio/input_dev fields.
lkkbd_disconnect() frees the lkkbd structure without cancelling this work, so the work can run after the structure has been freed, leading to a potential use-after-free.
Cancel the pending work in lkkbd_disconnect() before unregistering and freeing the device, following the same pattern as sunkbd.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Minseong Kim ii4gsp@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Minseong Kim ii4gsp@gmail.com --- drivers/input/keyboard/lkkbd.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/input/keyboard/lkkbd.c b/drivers/input/keyboard/lkkbd.c index c035216dd27c..72c477aab1fc 100644 --- a/drivers/input/keyboard/lkkbd.c +++ b/drivers/input/keyboard/lkkbd.c @@ -684,6 +684,8 @@ static void lkkbd_disconnect(struct serio *serio) { struct lkkbd *lk = serio_get_drvdata(serio);
+ cancel_work_sync(&lk->tq); + input_get_device(lk->dev); input_unregister_device(lk->dev); serio_close(serio);
Hi Minseong,
On Thu, Dec 11, 2025 at 12:11:31PM +0900, Minseong Kim wrote:
lkkbd_interrupt() schedules lk->tq with schedule_work(), and the work handler lkkbd_reinit() dereferences the lkkbd structure and its serio/input_dev fields.
lkkbd_disconnect() frees the lkkbd structure without cancelling this work, so the work can run after the structure has been freed, leading to a potential use-after-free.
Cancel the pending work in lkkbd_disconnect() before unregistering and freeing the device, following the same pattern as sunkbd.
Thank you for spotting this.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Minseong Kim ii4gsp@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Minseong Kim ii4gsp@gmail.com
drivers/input/keyboard/lkkbd.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/input/keyboard/lkkbd.c b/drivers/input/keyboard/lkkbd.c index c035216dd27c..72c477aab1fc 100644 --- a/drivers/input/keyboard/lkkbd.c +++ b/drivers/input/keyboard/lkkbd.c @@ -684,6 +684,8 @@ static void lkkbd_disconnect(struct serio *serio) { struct lkkbd *lk = serio_get_drvdata(serio);
- cancel_work_sync(&lk->tq);
We should use disable_work_sync() here because even if we cancel the work there is a chance it will be queued again (up until the moment serio_close() returns).
We also need to call disable_work_sync() in lkkbd_connect() in error paths once serio_open() has been called.
Thanks.
lkkbd_interrupt() schedules lk->tq via schedule_work(), and the work handler lkkbd_reinit() dereferences the lkkbd structure and its serio/input_dev fields.
lkkbd_disconnect() and error paths in lkkbd_connect() free the lkkbd structure without preventing the reinit work from being queued again until serio_close() returns. This can allow the work handler to run after the structure has been freed, leading to a potential use-after-free.
Use disable_work_sync() instead of cancel_work_sync() to ensure the reinit work cannot be re-queued, and call it both in lkkbd_disconnect() and in lkkbd_connect() error paths after serio_open().
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Minseong Kim ii4gsp@gmail.com --- drivers/input/keyboard/lkkbd.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/input/keyboard/lkkbd.c b/drivers/input/keyboard/lkkbd.c index c035216dd27c..12a467ce00b5 100644 --- a/drivers/input/keyboard/lkkbd.c +++ b/drivers/input/keyboard/lkkbd.c @@ -670,7 +670,8 @@ static int lkkbd_connect(struct serio *serio, struct serio_driver *drv)
return 0;
- fail3: serio_close(serio); + fail3: disable_work_sync(&lk->tq); + serio_close(serio); fail2: serio_set_drvdata(serio, NULL); fail1: input_free_device(input_dev); kfree(lk); @@ -684,6 +685,8 @@ static void lkkbd_disconnect(struct serio *serio) { struct lkkbd *lk = serio_get_drvdata(serio);
+ disable_work_sync(&lk->tq); + input_get_device(lk->dev); input_unregister_device(lk->dev); serio_close(serio);
lkkbd_interrupt() schedules lk->tq via schedule_work(), and the work handler lkkbd_reinit() dereferences the lkkbd structure and its serio/input_dev fields.
lkkbd_disconnect() and error paths in lkkbd_connect() free the lkkbd structure without preventing the reinit work from being queued again until serio_close() returns. This can allow the work handler to run after the structure has been freed, leading to a potential use-after-free.
Use disable_work_sync() instead of cancel_work_sync() to ensure the reinit work cannot be re-queued, and call it both in lkkbd_disconnect() and in lkkbd_connect() error paths after serio_open().
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Minseong Kim ii4gsp@gmail.com --- drivers/input/keyboard/lkkbd.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/input/keyboard/lkkbd.c b/drivers/input/keyboard/lkkbd.c index c035216dd27c..12a467ce00b5 100644 --- a/drivers/input/keyboard/lkkbd.c +++ b/drivers/input/keyboard/lkkbd.c @@ -670,7 +670,8 @@ static int lkkbd_connect(struct serio *serio, struct serio_driver *drv)
return 0;
- fail3: serio_close(serio); + fail3: disable_work_sync(&lk->tq); + serio_close(serio); fail2: serio_set_drvdata(serio, NULL); fail1: input_free_device(input_dev); kfree(lk); @@ -684,6 +685,8 @@ static void lkkbd_disconnect(struct serio *serio) { struct lkkbd *lk = serio_get_drvdata(serio);
+ disable_work_sync(&lk->tq); + input_get_device(lk->dev); input_unregister_device(lk->dev); serio_close(serio);
lkkbd_interrupt() schedules lk->tq via schedule_work(), and the work handler lkkbd_reinit() dereferences the lkkbd structure and its serio/input_dev fields.
lkkbd_disconnect() and error paths in lkkbd_connect() free the lkkbd structure without preventing the reinit work from being queued again until serio_close() returns. This can allow the work handler to run after the structure has been freed, leading to a potential use-after-free.
Use disable_work_sync() instead of cancel_work_sync() to ensure the reinit work cannot be re-queued, and call it both in lkkbd_disconnect() and in lkkbd_connect() error paths after serio_open().
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Minseong Kim ii4gsp@gmail.com --- drivers/input/keyboard/lkkbd.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/input/keyboard/lkkbd.c b/drivers/input/keyboard/lkkbd.c index c035216dd27c..12a467ce00b5 100644 --- a/drivers/input/keyboard/lkkbd.c +++ b/drivers/input/keyboard/lkkbd.c @@ -670,7 +670,8 @@ static int lkkbd_connect(struct serio *serio, struct serio_driver *drv)
return 0;
- fail3: serio_close(serio); + fail3: disable_work_sync(&lk->tq); + serio_close(serio); fail2: serio_set_drvdata(serio, NULL); fail1: input_free_device(input_dev); kfree(lk); @@ -684,6 +685,8 @@ static void lkkbd_disconnect(struct serio *serio) { struct lkkbd *lk = serio_get_drvdata(serio);
+ disable_work_sync(&lk->tq); + input_get_device(lk->dev); input_unregister_device(lk->dev); serio_close(serio);
On Fri, Dec 12, 2025 at 02:23:14PM +0900, Minseong Kim wrote:
lkkbd_interrupt() schedules lk->tq via schedule_work(), and the work handler lkkbd_reinit() dereferences the lkkbd structure and its serio/input_dev fields.
lkkbd_disconnect() and error paths in lkkbd_connect() free the lkkbd structure without preventing the reinit work from being queued again until serio_close() returns. This can allow the work handler to run after the structure has been freed, leading to a potential use-after-free.
Use disable_work_sync() instead of cancel_work_sync() to ensure the reinit work cannot be re-queued, and call it both in lkkbd_disconnect() and in lkkbd_connect() error paths after serio_open().
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Minseong Kim ii4gsp@gmail.com
Applied, thank you.
linux-stable-mirror@lists.linaro.org
-
Dmitry Torokhov -
Minseong Kim