can: isotp: return -EADDRNOTAVAIL when reading from unbound socket

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>

diff --git a/net/can/isotp.c b/net/can/isotp.c
index 1662103..6b6c822 100644 (file)
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -1046,12 +1046,16 @@ static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
 {
        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;