tcp: Fix listen() regression in 5.15.88.

stable inclusion
from stable-v5.15.95
commit fdaf88531cfd17b2a710cceb3141ef6f9085ff40
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I6H3MB
CVE: CVE-2023-0461

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fdaf88531cfd17b2a710cceb3141ef6f9085ff40

---------------------------

When we backport dadd0dcaa67d ("net/ulp: prevent ULP without clone op from
entering the LISTEN status"), we have accidentally backported a part of
7a7160ed ("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: NWinter <winter@winter.cafe>
Signed-off-by: NKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NLiu Jian <liujian56@huawei.com>
Reviewed-by: NYue Haibing <yuehaibing@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>

net/ipv4/inet_connection_sock.c

@@ -941,6 +941,7 @@ 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);