Commit 8375dfac authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by Marc Kleine-Budde
Browse files

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

Commit 43a08c3b ("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: 43a08c3b ("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: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 7c759040

net/can/isotp.c

+9 −6
Original line number Diff line number Diff line
@@ -887,7 +887,7 @@ 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;

	}



	/* take care of a potential SF_DL ESC offset for TX_DL > 8 */
@@ -897,24 +897,24 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) 
	if ((so->opt.flags & CAN_ISOTP_SF_BROADCAST) &&

	    (size > so->tx.ll_dl - SF_PCI_SZ4 - ae - off)) {

		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);
@@ -976,7 +976,7 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) 
	if (err) {

		pr_notice_once("can-isotp: %s: can_send_ret %pe\n",

			       __func__, ERR_PTR(err));

		goto err_out;

		goto err_out_drop;

	}



	if (wait_tx_done) {
@@ -989,6 +989,9 @@ 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)