This is a note to let you know that I've just added the patch titled
ax25: fix use-after-free bugs caused by ax25_ds_del_timer
to the 6.8-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:
ax25-fix-use-after-free-bugs-caused-by-ax25_ds_del_timer.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From fd819ad3ecf6f3c232a06b27423ce9ed8c20da89 Mon Sep 17 00:00:00 2001
From: Duoming Zhou <duoming@xxxxxxxxxx>
Date: Fri, 29 Mar 2024 09:50:23 +0800
Subject: ax25: fix use-after-free bugs caused by ax25_ds_del_timer
From: Duoming Zhou <duoming@xxxxxxxxxx>
commit fd819ad3ecf6f3c232a06b27423ce9ed8c20da89 upstream.
When the ax25 device is detaching, the ax25_dev_device_down()
calls ax25_ds_del_timer() to cleanup the slave_timer. When
the timer handler is running, the ax25_ds_del_timer() that
calls del_timer() in it will return directly. As a result,
the use-after-free bugs could happen, one of the scenarios
is shown below:
(Thread 1) | (Thread 2)
| ax25_ds_timeout()
ax25_dev_device_down() |
ax25_ds_del_timer() |
del_timer() |
ax25_dev_put() //FREE |
| ax25_dev-> //USE
In order to mitigate bugs, when the device is detaching, use
timer_shutdown_sync() to stop the timer.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Duoming Zhou <duoming@xxxxxxxxxx>
Reviewed-by: Simon Horman <horms@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240329015023.9223-1-duoming@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ax25/ax25_dev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/ax25/ax25_dev.c
+++ b/net/ax25/ax25_dev.c
@@ -105,7 +105,7 @@ void ax25_dev_device_down(struct net_dev
spin_lock_bh(&ax25_dev_lock);
#ifdef CONFIG_AX25_DAMA_SLAVE
- ax25_ds_del_timer(ax25_dev);
+ timer_shutdown_sync(&ax25_dev->dama.slave_timer);
#endif
/*
Patches currently in stable-queue which might be from duoming@xxxxxxxxxx are
queue-6.8/ax25-fix-use-after-free-bugs-caused-by-ax25_ds_del_timer.patch
