[PATCH net v2 1/3] af_unix: fix listen() succeeding on sockets in the wrong state
From: John Ericson <hidden>
Date: 2026-07-03 08:15:06
Also in:
lkml
Subsystem:
networking [general], networking [unix sockets], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Kuniyuki Iwashima, Linus Torvalds
From: John Ericson <redacted>
Commit fd0a109a0f6b ("net, pidfs: prepare for handing out pidfds for
reaped sk->sk_peer_pid") inserted a `prepare_peercred()` call between
`err = -EINVAL` and the socket-state check in `unix_listen()`. Since
`prepare_peercred()` leaves `err` at 0 on success, `listen()` on an
AF_UNIX socket that is not in `TCP_CLOSE` or `TCP_LISTEN` state (e.g.
one that is already connected) now silently returns success without
doing anything, instead of failing with `EINVAL` as it did before.
Fixes: fd0a109a0f6b ("net, pidfs: prepare for handing out pidfds for reaped sk->sk_peer_pid")
Assisted-by: Claude:claude-fable-5
Signed-off-by: John Ericson <redacted>
---
net/unix/af_unix.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index f7a9d55eee8a..10ed9421e43a 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c@@ -823,6 +823,7 @@ static int unix_listen(struct socket *sock, int backlog) if (err) goto out; unix_state_lock(sk); + err = -EINVAL; if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN) goto out_unlock; if (backlog > sk->sk_max_ack_backlog)
--
2.54.0