From: Hyunwoo Kim <v4bel@xxxxxxxxx> [ Upstream commit 14caefcf9837a2be765a566005ad82cd0d2a429f ] If you call listen() and accept() on an already connect()ed rose socket, accept() can successfully connect. This is because when the peer socket sends data to sendmsg, the skb with its own sk stored in the connected socket's sk->sk_receive_queue is connected, and rose_accept() dequeues the skb waiting in the sk->sk_receive_queue. This creates a child socket with the sk of the parent rose socket, which can cause confusion. Fix rose_listen() to return -EINVAL if the socket has already been successfully connected, and add lock_sock to prevent this issue. Signed-off-by: Hyunwoo Kim <v4bel@xxxxxxxxx> Reviewed-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> Link: https://lore.kernel.org/r/20230125105944.GA133314@ubuntu Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- net/rose/af_rose.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c index 29a208ed8fb88..86c93cf1744b0 100644 --- a/net/rose/af_rose.c +++ b/net/rose/af_rose.c @@ -487,6 +487,12 @@ static int rose_listen(struct socket *sock, int backlog) { struct sock *sk = sock->sk; + lock_sock(sk); + if (sock->state != SS_UNCONNECTED) { + release_sock(sk); + return -EINVAL; + } + if (sk->sk_state != TCP_LISTEN) { struct rose_sock *rose = rose_sk(sk); @@ -496,8 +502,10 @@ static int rose_listen(struct socket *sock, int backlog) memset(rose->dest_digis, 0, AX25_ADDR_LEN * ROSE_MAX_DIGIS); sk->sk_max_ack_backlog = backlog; sk->sk_state = TCP_LISTEN; + release_sock(sk); return 0; } + release_sock(sk); return -EOPNOTSUPP; } -- 2.39.0
