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| author | Duoming Zhou <duoming@zju.edu.cn> | 2022-04-05 21:22:06 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-20 09:12:50 +0200 |
| commit | 753b9d220a7d36dac70e7c6d05492d10d6f9dd36 (patch) | |
| tree | 18fdd2cb2920a9ea244187c27ff552c8e2c0d605 /drivers/net/slip | |
| parent | f49dfedc6f6e9de223c5d2be57652ccbcaeb820a (diff) | |
| download | linux-stable-753b9d220a7d36dac70e7c6d05492d10d6f9dd36.tar.gz linux-stable-753b9d220a7d36dac70e7c6d05492d10d6f9dd36.tar.bz2 linux-stable-753b9d220a7d36dac70e7c6d05492d10d6f9dd36.zip | |
drivers: net: slip: fix NPD bug in sl_tx_timeout()
[ Upstream commit ec4eb8a86ade4d22633e1da2a7d85a846b7d1798 ]
When a slip driver is detaching, the slip_close() will act to
cleanup necessary resources and sl->tty is set to NULL in
slip_close(). Meanwhile, the packet we transmit is blocked,
sl_tx_timeout() will be called. Although slip_close() and
sl_tx_timeout() use sl->lock to synchronize, we don`t judge
whether sl->tty equals to NULL in sl_tx_timeout() and the
null pointer dereference bug will happen.
(Thread 1) | (Thread 2)
| slip_close()
| spin_lock_bh(&sl->lock)
| ...
... | sl->tty = NULL //(1)
sl_tx_timeout() | spin_unlock_bh(&sl->lock)
spin_lock(&sl->lock); |
... | ...
tty_chars_in_buffer(sl->tty)|
if (tty->ops->..) //(2) |
... | synchronize_rcu()
We set NULL to sl->tty in position (1) and dereference sl->tty
in position (2).
This patch adds check in sl_tx_timeout(). If sl->tty equals to
NULL, sl_tx_timeout() will goto out.
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20220405132206.55291-1-duoming@zju.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/net/slip')
| -rw-r--r-- | drivers/net/slip/slip.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/slip/slip.c b/drivers/net/slip/slip.c index 5d864f812955..3ec8d16a4633 100644 --- a/drivers/net/slip/slip.c +++ b/drivers/net/slip/slip.c @@ -471,7 +471,7 @@ static void sl_tx_timeout(struct net_device *dev) spin_lock(&sl->lock); if (netif_queue_stopped(dev)) { - if (!netif_running(dev)) + if (!netif_running(dev) || !sl->tty) goto out; /* May be we must check transmitter timeout here ? |