af_unix: Fix memleak of newsk in unix_stream_connect().

When prepare_peercred() fails in unix_stream_connect(),
unix_release_sock() is not called for newsk, and the memory
is leaked.

Let's move prepare_peercred() before unix_create1().

Fixes: fd0a109 ("net, pidfs: prepare for handing out pidfds for reaped sk->sk_peer_pid")
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260207232236.2557549-1-kuniyu@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: q2ven

net/unix/af_unix.c

@@ -1650,10 +1650,9 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr_unsized *uad
 
 	timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
 
-	/* First of all allocate resources.
-	 * If we will make it after state is locked,
-	 * we will have to recheck all again in any case.
-	 */
+	err = prepare_peercred(&peercred);
+	if (err)
+		goto out;
 
 	/* create new sock for complete connection */
 	newsk = unix_create1(net, NULL, 0, sock->type);
@@ -1662,10 +1661,6 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr_unsized *uad
 		goto out;
 	}
 
-	err = prepare_peercred(&peercred);
-	if (err)
-		goto out;
-
 	/* Allocate skb for sending to listening sock */
 	skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
 	if (!skb) {