mISDN: fix possible use-after-free in HFC_cleanup()

[ Upstream commit 009fc857c5 ]

This module's remove path calls del_timer(). However, that function
does not wait until the timer handler finishes. This means that the
timer handler may still be running after the driver's remove function
has finished, which would result in a use-after-free.

Fix by calling del_timer_sync(), which makes sure the timer handler
has finished, and unable to re-schedule itself.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Zou Wei 2021-05-11 14:58:53 +08:00 committed by Greg Kroah-Hartman
parent 89ce0b0747
commit 5f2818185d

View file

@ -2348,7 +2348,7 @@ static void __exit
HFC_cleanup(void)
{
if (timer_pending(&hfc_tl))
del_timer(&hfc_tl);
del_timer_sync(&hfc_tl);
pci_unregister_driver(&hfc_driver);
}