net/ulp: use consistent error code when blocking ULP

jira VULN-3655
cve-bf CVE-2023-0461
commit-author Paolo Abeni <[email protected]>
commit 8ccc993
upstream-diff This commit is the closure of
              68e4adc, solving two
              issues:
              1. The backported mainline fix
                 2c02d41 had a
                 follow-up in
                 8ccc993, which was
                 missing from `ciqlts8_6'. (The original intent of
                 the cherry-picked commit)
              2. The way changes to `inet_csk_listen_start' were
                 applied from upstream left a potential branching
                 path which would result in the returned `err'
                 different than before the change, for the exact
                 same inputs. While effectively ignoring the
                 initialization of `err' to `-EADDRINUSE' was
                 justified in upstream because of the inevitable
                 assignment at line 1237, the same cannot be done in
                 the versions prior to 9.2 as the initial
                 `-EADDRINUSE' can survive in `err' up to its
                 returning from function. (The piggy-backed
                 correction included here for the lack of better
                 place)

The referenced commit changed the error code returned by the kernel
when preventing a non-established socket from attaching the ktls
ULP. Before to such a commit, the user-space got ENOTCONN instead
of EINVAL.

The existing self-tests depend on such error code, and the change
caused a failure:

  RUN           global.non_established ...
 tls.c:1673:non_established:Expected errno (22) == ENOTCONN (107)
 non_established: Test failed at step #3
          FAIL  global.non_established

In the unlikely event existing applications do the same, address
the issue by restoring the prior error code in the above scenario.

Note that the only other ULP performing similar checks at init
time - smc_ulp_ops - also fails with ENOTCONN when trying to attach
the ULP to a non-established socket.

	Reported-by: Sabrina Dubroca <[email protected]>
Fixes: 2c02d41 ("net/ulp: prevent ULP without clone op from entering the LISTEN status")
	Signed-off-by: Paolo Abeni <[email protected]>
	Reviewed-by: Sabrina Dubroca <[email protected]>
Link: https://lore.kernel.org/r/7bb199e7a93317fb6f8bf8b9b2dc71c18f337cde.1674042685.git.pabeni@redhat.com
	Signed-off-by: Jakub Kicinski <[email protected]>
(cherry picked from commit 8ccc993)
	Signed-off-by: Marcin Wcisło <[email protected]>

Author: pvts-mat

net/ipv4/inet_connection_sock.c

@@ -920,6 +920,7 @@ int inet_csk_listen_start(struct sock *sk, int backlog)
 	if (unlikely(err))
 		return err;
 
+	err = -EADDRINUSE;
 	reqsk_queue_alloc(&icsk->icsk_accept_queue);
 
 	sk->sk_ack_backlog = 0;

net/ipv4/tcp_ulp.c

@@ -131,7 +131,7 @@ static int __tcp_set_ulp(struct sock *sk, const struct tcp_ulp_ops *ulp_ops)
 	if (icsk->icsk_ulp_ops)
 		goto out_err;
 
-	err = -EINVAL;
+	err = -ENOTCONN;
 	if (!ulp_ops->clone && sk->sk_state == TCP_LISTEN)
 		goto out_err;