tcp: Fix listen() regression in 4.19.270

commit fdaf88531cfd17b2a710cceb3141ef6f9085ff40 upstream.

When we backport dadd0dcaa67d ("net/ulp: prevent ULP without clone op from
entering the LISTEN status"), we have accidentally backported a part of
7a7160edf1bf ("net: Return errno in sk->sk_prot->get_port().") and removed
err = -EADDRINUSE in inet_csk_listen_start().

Thus, listen() no longer returns -EADDRINUSE even if ->get_port() failed
as reported in [0].

We set -EADDRINUSE to err just before ->get_port() to fix the regression.

[0]: https://lore.kernel.org/stable/EF8A45D0-768A-4CD5-9A8A-0FA6E610ABF7@winter.cafe/

Reported-by: Winter <winter@winter.cafe>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 457f619a34610b95611064edd5ed2e3ba93429e2..0f9085220ecf94b1fdfc1f5b32142a71c9d758b5 100644 (file)
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -934,6 +934,7 @@ int inet_csk_listen_start(struct sock *sk, int backlog)
         * It is OK, because this socket enters to hash table only
         * after validation is complete.
         */
+       err = -EADDRINUSE;
        inet_sk_state_store(sk, TCP_LISTEN);
        if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
                inet->inet_sport = htons(inet->inet_num);