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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Derek Will <derekrobertwill@gmail.com>,
        Oliver Hartkopp <socketcan@hartkopp.net>,
        Marc Kleine-Budde <mkl@pengutronix.de>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 550/913] can: isotp: return -EADDRNOTAVAIL when reading from unbound socket
Date:   Tue,  5 Apr 2022 09:26:52 +0200
Message-Id: <20220405070356.334244799@linuxfoundation.org>
In-Reply-To: <20220405070339.801210740@linuxfoundation.org>
References: <20220405070339.801210740@linuxfoundation.org>
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From: Oliver Hartkopp <socketcan@hartkopp.net>

[ Upstream commit 30ffd5332e06316bd69a654c06aa033872979b7c ]

When reading from an unbound can-isotp socket the syscall blocked
indefinitely. As unbound sockets (without given CAN address information)
do not make sense anyway we directly return -EADDRNOTAVAIL on read()
analogue to the known behavior from sendmsg().

Fixes: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol")
Link: https://github.com/linux-can/can-utils/issues/349
Link: https://lore.kernel.org/all/20220316164258.54155-2-socketcan@hartkopp.net
Suggested-by: Derek Will <derekrobertwill@gmail.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/can/isotp.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -1005,12 +1005,16 @@ static int isotp_recvmsg(struct socket *
 {
 	struct sock *sk = sock->sk;
 	struct sk_buff *skb;
+	struct isotp_sock *so = isotp_sk(sk);
 	int err = 0;
 	int noblock;
 
 	noblock = flags & MSG_DONTWAIT;
 	flags &= ~MSG_DONTWAIT;
 
+	if (!so->bound)
+		return -EADDRNOTAVAIL;
+
 	skb = skb_recv_datagram(sk, flags, noblock, &err);
 	if (!skb)
 		return err;