This is a note to let you know that I've just added the patch titled
mISDN: fix possible use-after-free in HFC_cleanup()
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
misdn-fix-possible-use-after-free-in-hfc_cleanup.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 48fd166472d8cf68efa34d3c441bba8b937c2459
Author: Zou Wei <zou_wei@xxxxxxxxxx>
Date: Tue May 11 14:58:53 2021 +0800
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@xxxxxxxxxx>
Signed-off-by: Zou Wei <zou_wei@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/isdn/hardware/mISDN/hfcpci.c b/drivers/isdn/hardware/mISDN/hfcpci.c
index 2330a7d24267..a2b2ce1dfec8 100644
--- a/drivers/isdn/hardware/mISDN/hfcpci.c
+++ b/drivers/isdn/hardware/mISDN/hfcpci.c
@@ -2341,7 +2341,7 @@ 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);
}
