diff options
| author | Oliver Hartkopp <socketcan@hartkopp.net> | 2026-03-19 16:47:45 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-04-02 13:25:40 +0200 |
| commit | 2e62e7051eca75a7f2e3d52d62ec10d7d7aa358c (patch) | |
| tree | b8801cb18d3af3cf948e2d4b8a158c6f88dd6f95 /net/can | |
| parent | 66b689efd08227da2c5ca49b58b30a95d23c695a (diff) | |
can: isotp: fix tx.buf use-after-free in isotp_sendmsg()
commit 424e95d62110cdbc8fd12b40918f37e408e35a92 upstream.
isotp_sendmsg() uses only cmpxchg() on so->tx.state to serialize access
to so->tx.buf. isotp_release() waits for ISOTP_IDLE via
wait_event_interruptible() and then calls kfree(so->tx.buf).
If a signal interrupts the wait_event_interruptible() inside close()
while tx.state is ISOTP_SENDING, the loop exits early and release
proceeds to force ISOTP_SHUTDOWN and continues to kfree(so->tx.buf)
while sendmsg may still be reading so->tx.buf for the final CAN frame
in isotp_fill_dataframe().
The so->tx.buf can be allocated once when the standard tx.buf length needs
to be extended. Move the kfree() of this potentially extended tx.buf to
sk_destruct time when either isotp_sendmsg() and isotp_release() are done.
Fixes: 96d1c81e6a04 ("can: isotp: add module parameter for maximum pdu size")
Cc: stable@vger.kernel.org
Reported-by: Ali Norouzi <ali.norouzi@keysight.com>
Co-developed-by: Ali Norouzi <ali.norouzi@keysight.com>
Signed-off-by: Ali Norouzi <ali.norouzi@keysight.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://patch.msgid.link/20260319-fix-can-gw-and-can-isotp-v2-2-c45d52c6d2d8@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/can')
| -rw-r--r-- | net/can/isotp.c | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/net/can/isotp.c b/net/can/isotp.c index ce588b85665a..3811c4d0957a 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -1230,12 +1230,6 @@ static int isotp_release(struct socket *sock) so->ifindex = 0; so->bound = 0; - if (so->rx.buf != so->rx.sbuf) - kfree(so->rx.buf); - - if (so->tx.buf != so->tx.sbuf) - kfree(so->tx.buf); - sock_orphan(sk); sock->sk = NULL; @@ -1604,6 +1598,21 @@ static int isotp_notifier(struct notifier_block *nb, unsigned long msg, return NOTIFY_DONE; } +static void isotp_sock_destruct(struct sock *sk) +{ + struct isotp_sock *so = isotp_sk(sk); + + /* do the standard CAN sock destruct work */ + can_sock_destruct(sk); + + /* free potential extended PDU buffers */ + if (so->rx.buf != so->rx.sbuf) + kfree(so->rx.buf); + + if (so->tx.buf != so->tx.sbuf) + kfree(so->tx.buf); +} + static int isotp_init(struct sock *sk) { struct isotp_sock *so = isotp_sk(sk); @@ -1648,6 +1657,9 @@ static int isotp_init(struct sock *sk) list_add_tail(&so->notifier, &isotp_notifier_list); spin_unlock(&isotp_notifier_lock); + /* re-assign default can_sock_destruct() reference */ + sk->sk_destruct = isotp_sock_destruct; + return 0; } |