diff options
| author | Eric Dumazet <edumazet@google.com> | 2026-08-26 10:52:38 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-08-27 12:38:27 -0700 |
| commit | 23c53269f2baaedf2d92784290cb9ef6db2a3bce (patch) | |
| tree | 956574aa5e44baeb5b212748a2e9053da7797045 | |
| parent | 50e5c6605cc9c2dd57bd2d1b3459674d19738983 (diff) | |
slip: remove slip_hangup() to fix use-after-free in slip_receive_buf()
Jaeyoung Chung and Eulgyu Kim reported a slab-use-after-free read
in slip_receive_buf() when racing against tty hangup.
tty_ldisc_hangup() calls ld->ops->hangup() while holding only
a read lock on tty->ldisc_sem (via tty_ldisc_ref()).
Because slip_hangup() simply called slip_close(), it ran concurrently
with reader functions such as slip_receive_buf().
slip_close() unregisters and frees the net device and its private
struct slip, causing concurrent reader threads in slip_receive_buf()
to dereference freed memory.
Line discipline close() is already guaranteed to be called under
the write lock of tty->ldisc_sem during hangup processing
(in tty_ldisc_reinit() or tty_ldisc_kill()).
Remove slip_hangup() so teardown is serialized cleanly by slip_close().
Fixes: 5342b77c4123 ("slip: Clean up create and destroy")
Reported-by: Jaeyoung Chung <jjy600901@snu.ac.kr>
Reported-by: Eulgyu Kim <eulgyukim@snu.ac.kr>
Closes: https://lore.kernel.org/netdev/20260825150655.1450271-1-jjy600901@snu.ac.kr/
Cc: Qingfang Deng <qingfang.deng@linux.dev>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260826105238.3323436-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | drivers/net/slip/slip.c | 8 |
1 files changed, 0 insertions, 8 deletions
diff --git a/drivers/net/slip/slip.c b/drivers/net/slip/slip.c index 85b2438e8923..fdd6f63fb849 100644 --- a/drivers/net/slip/slip.c +++ b/drivers/net/slip/slip.c @@ -886,8 +886,6 @@ err_exit: * Close down a SLIP channel. * This means flushing out any pending queues, and then returning. This * call is serialized against other ldisc functions. - * - * We also use this method fo a hangup event */ static void slip_close(struct tty_struct *tty) @@ -915,11 +913,6 @@ static void slip_close(struct tty_struct *tty) unregister_netdev(sl->dev); /* sl_uninit() has dropped the slip_devs[] entry by now */ } - -static void slip_hangup(struct tty_struct *tty) -{ - slip_close(tty); -} /************************************************************************ * STANDARD SLIP ENCAPSULATION * ************************************************************************/ @@ -1280,7 +1273,6 @@ static struct tty_ldisc_ops sl_ldisc = { .name = "slip", .open = slip_open, .close = slip_close, - .hangup = slip_hangup, .ioctl = slip_ioctl, .receive_buf = slip_receive_buf, .write_wakeup = slip_write_wakeup, |