Commit 54ff3202 authored May 11, 2021 by Zou Wei Committed by Greg Kroah-Hartman Jul 20, 2021

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



[ Upstream commit 009fc857c5f6fda81f2f7dd851b2d54193a8e733 ]

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>

parent a832ee2f

drivers/isdn/hardware/mISDN/hfcpci.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -2352,7 +2352,7 @@ 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);
		}