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can: isotp: fix error path in isotp_sendmsg() to unlock wait queue

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commit 8375dfac4f upstream.

Commit 43a08c3bda ("can: isotp: isotp_sendmsg(): fix TX buffer concurrent
access in isotp_sendmsg()") introduced a new locking scheme that may render
the userspace application in a locking state when an error is detected.
This issue shows up under high load on simultaneously running isotp channels
with identical configuration which is against the ISO specification and
therefore breaks any reasonable PDU communication anyway.

Fixes: 43a08c3bda ("can: isotp: isotp_sendmsg(): fix TX buffer concurrent access in isotp_sendmsg()")
Link: https://lore.kernel.org/all/20220209073601.25728-1-socketcan@hartkopp.net
Cc: stable@vger.kernel.org
Cc: Ziyang Xuan <william.xuanziyang@huawei.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Oliver Hartkopp 2022-02-09 08:36:01 +01:00 • committed by Greg Kroah-Hartman
commit 199dab00f0
1 changed files with 8 additions and 5 deletions
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13
net/can/isotp.c
View file

@ -885,24 +885,24 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
if (!size || size > MAX_MSG_LENGTH) {
err = -EINVAL;
goto err_out;
goto err_out_drop;
}
err = memcpy_from_msg(so->tx.buf, msg, size);
if (err < 0)
goto err_out;
goto err_out_drop;
dev = dev_get_by_index(sock_net(sk), so->ifindex);
if (!dev) {
err = -ENXIO;
goto err_out;
goto err_out_drop;
}
skb = sock_alloc_send_skb(sk, so->ll.mtu + sizeof(struct can_skb_priv),
msg->msg_flags & MSG_DONTWAIT, &err);
if (!skb) {
dev_put(dev);
goto err_out;
goto err_out_drop;
}
can_skb_reserve(skb);
@ -967,7 +967,7 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
if (err) {
pr_notice_once("can-isotp: %s: can_send_ret %d\n",
__func__, err);
goto err_out;
goto err_out_drop;
}
if (wait_tx_done) {
@ -980,6 +980,9 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
return size;
err_out_drop:
/* drop this PDU and unlock a potential wait queue */
old_state = ISOTP_IDLE;
err_out:
so->tx.state = old_state;
if (so->tx.state == ISOTP_IDLE)