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| author |   Duoming Zhou <duoming@zju.edu.cn> | 2022-04-05 21:22:06 +0800 |
|---|---|---|
| committer |   Jakub Kicinski <kuba@kernel.org> | 2022-04-06 23:00:16 -0700 |
| commit | ec4eb8a86ade4d22633e1da2a7d85a846b7d1798 (patch) | |
| tree | 83177045d62c3294479a81517c3a3ca68636b7a2 /drivers/net/slip/slip.c | |
| parent | Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf (diff) | |
| download | linux-dev-ec4eb8a86ade4d22633e1da2a7d85a846b7d1798.tar.xz linux-dev-ec4eb8a86ade4d22633e1da2a7d85a846b7d1798.zip | |
drivers: net: slip: fix NPD bug in sl_tx_timeout()
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>
Diffstat (limited to 'drivers/net/slip/slip.c')
| -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 88396ff99f03..6865d32270e5 100644 --- a/drivers/net/slip/slip.c +++ b/drivers/net/slip/slip.c @@ -469,7 +469,7 @@ static void sl_tx_timeout(struct net_device *dev, unsigned int txqueue) 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 ? |