From: Duoming Zhou <duoming@zju.edu.cn>
To: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, linux-hams@vger.kernel.org,
pabeni@redhat.com, kuba@kernel.org, edumazet@google.com,
davem@davemloft.net, jreuter@yaina.de, horms@kernel.org,
Duoming Zhou <duoming@zju.edu.cn>
Subject: [PATCH net v2] ax25: fix use-after-free bugs caused by ax25_ds_del_timer
Date: Fri, 29 Mar 2024 09:50:23 +0800 [thread overview]
Message-ID: <20240329015023.9223-1-duoming@zju.edu.cn> (raw)
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@zju.edu.cn>
---
Changes in v2:
- Call timer_shutdown_sync() in ax25_dev_device_down().
net/ax25/ax25_dev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c
index c5462486dbc..282ec581c07 100644
--- a/net/ax25/ax25_dev.c
+++ b/net/ax25/ax25_dev.c
@@ -105,7 +105,7 @@ void ax25_dev_device_down(struct net_device *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
/*
--
2.17.1
next reply other threads:[~2024-03-29 1:50 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-29 1:50 Duoming Zhou [this message]
2024-03-31 9:32 ` [PATCH net v2] ax25: fix use-after-free bugs caused by ax25_ds_del_timer Simon Horman
2024-04-03 1:10 ` patchwork-bot+netdevbpf
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