| Message ID | 20230123142123.58870-1-duoming@zju.edu.cn |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] media: rc: Fix use-after-free bugs caused by ene_tx_irqsim() | expand |
diff --git a/drivers/media/rc/ene_ir.c b/drivers/media/rc/ene_ir.c index e09270916fb..2864360af9e 100644 --- a/drivers/media/rc/ene_ir.c +++ b/drivers/media/rc/ene_ir.c @@ -1112,8 +1112,9 @@ static void ene_remove(struct pnp_dev *pnp_dev) spin_unlock_irqrestore(&dev->hw_lock, flags); free_irq(dev->irq, dev); - release_region(dev->hw_io, ENE_IO_SIZE); rc_unregister_device(dev->rdev); + del_timer_sync(&dev->tx_sim_timer); + release_region(dev->hw_io, ENE_IO_SIZE); kfree(dev); }
When the ene device is detaching, function ene_remove() will be called. But there is no function to cancel tx_sim_timer in ene_remove(), the timer handler ene_tx_irqsim() could race with ene_remove(). As a result, the UAF bugs could happen, the process is shown below. (cleanup routine) | (timer routine) | mod_timer(&dev->tx_sim_timer, ..) ene_remove() | (wait a time) kfree(dev) //FREE | | ene_tx_irqsim() | dev->hw_lock //USE | ene_tx_sample(dev) //USE Fix by adding del_timer_sync(&dev->tx_sim_timer) in ene_remove(), The tx_sim_timer could stop before ene device is deallocated. What's more, the timer can call ene_tx_sample() which can write to the io ports. So we should put rc_unregister_device() and del_timer_sync(&dev->tx_sim_timer) before release_region() in ene_remove(). Fixes: 9ea53b74df9c ("V4L/DVB: STAGING: remove lirc_ene0100 driver") Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> --- Changes in v2: - Move rc_unregister_device() and del_timer_sync() before release_region(). drivers/media/rc/ene_ir.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)