From 73e341e0281a35274629e9be27eae2f9b1b492bf Mon Sep 17 00:00:00 2001 From: Yang Yingliang Date: Thu, 8 Dec 2022 23:01:58 +0800 Subject: af_unix: call proto_unregister() in the error path in af_unix_init() If register unix_stream_proto returns error, unix_dgram_proto needs be unregistered. Fixes: 94531cfcbe79 ("af_unix: Add unix_stream_proto for sockmap") Signed-off-by: Yang Yingliang Reviewed-by: Simon Horman Reviewed-by: Kuniyuki Iwashima Signed-off-by: David S. Miller --- net/unix/af_unix.c | 1 + 1 file changed, 1 insertion(+) (limited to 'net/unix/af_unix.c') diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index b3545fc68097..ede2b2a140a4 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -3738,6 +3738,7 @@ static int __init af_unix_init(void) rc = proto_register(&unix_stream_proto, 1); if (rc != 0) { pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__); + proto_unregister(&unix_dgram_proto); goto out; } -- cgit v1.2.3 From 3ff8bff704f4de125dca2262e5b5b963a3da1d87 Mon Sep 17 00:00:00 2001 From: Kirill Tkhai Date: Tue, 13 Dec 2022 00:05:53 +0300 Subject: unix: Fix race in SOCK_SEQPACKET's unix_dgram_sendmsg() There is a race resulting in alive SOCK_SEQPACKET socket may change its state from TCP_ESTABLISHED to TCP_CLOSE: unix_release_sock(peer) unix_dgram_sendmsg(sk) sock_orphan(peer) sock_set_flag(peer, SOCK_DEAD) sock_alloc_send_pskb() if !(sk->sk_shutdown & SEND_SHUTDOWN) OK if sock_flag(peer, SOCK_DEAD) sk->sk_state = TCP_CLOSE sk->sk_shutdown = SHUTDOWN_MASK After that socket sk remains almost normal: it is able to connect, listen, accept and recvmsg, while it can't sendmsg. Since this is the only possibility for alive SOCK_SEQPACKET to change the state in such way, we should better fix this strange and potentially danger corner case. Note, that we will return EPIPE here like this is normally done in sock_alloc_send_pskb(). Originally used ECONNREFUSED looks strange, since it's strange to return a specific retval in dependence of race in kernel, when user can't affect on this. Also, move TCP_CLOSE assignment for SOCK_DGRAM sockets under state lock to fix race with unix_dgram_connect(): unix_dgram_connect(other) unix_dgram_sendmsg(sk) unix_peer(sk) = NULL unix_state_unlock(sk) unix_state_double_lock(sk, other) sk->sk_state = TCP_ESTABLISHED unix_peer(sk) = other unix_state_double_unlock(sk, other) sk->sk_state = TCP_CLOSED This patch fixes both of these races. Fixes: 83301b5367a9 ("af_unix: Set TCP_ESTABLISHED for datagram sockets too") Signed-off-by: Kirill Tkhai Link: https://lore.kernel.org/r/135fda25-22d5-837a-782b-ceee50e19844@ya.ru Signed-off-by: Paolo Abeni --- net/unix/af_unix.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'net/unix/af_unix.c') diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index ede2b2a140a4..f0c2293f1d3b 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -1999,13 +1999,20 @@ restart_locked: unix_state_lock(sk); err = 0; - if (unix_peer(sk) == other) { + if (sk->sk_type == SOCK_SEQPACKET) { + /* We are here only when racing with unix_release_sock() + * is clearing @other. Never change state to TCP_CLOSE + * unlike SOCK_DGRAM wants. + */ + unix_state_unlock(sk); + err = -EPIPE; + } else if (unix_peer(sk) == other) { unix_peer(sk) = NULL; unix_dgram_peer_wake_disconnect_wakeup(sk, other); + sk->sk_state = TCP_CLOSE; unix_state_unlock(sk); - sk->sk_state = TCP_CLOSE; unix_dgram_disconnected(sk, other); sock_put(other); err = -ECONNREFUSED; -- cgit v1.2.3