net/ulp: prevent ULP without clone op from entering the LISTEN status

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2162758
Tested: tls self-tests

Upstream commit:
commit 2c02d41
Author: Paolo Abeni <[email protected]>
Date:   Tue Jan 3 12:19:17 2023 +0100

    net/ulp: prevent ULP without clone op from entering the LISTEN status

    When an ULP-enabled socket enters the LISTEN status, the listener ULP data
    pointer is copied inside the child/accepted sockets by sk_clone_lock().

    The relevant ULP can take care of de-duplicating the context pointer via
    the clone() operation, but only MPTCP and SMC implement such op.

    Other ULPs may end-up with a double-free at socket disposal time.

    We can't simply clear the ULP data at clone time, as TLS replaces the
    socket ops with custom ones assuming a valid TLS ULP context is
    available.

    Instead completely prevent clone-less ULP sockets from entering the
    LISTEN status.

    Fixes: 734942c ("tcp: ULP infrastructure")
    Reported-by: slipper <[email protected]>
    Signed-off-by: Paolo Abeni <[email protected]>
    Link: https://lore.kernel.org/r/4b80c3d1dbe3d0ab072f80450c202d9bc88b4b03.1672740602.git.pabeni@redhat.com
    Signed-off-by: Jakub Kicinski <[email protected]>

Signed-off-by: Paolo Abeni <[email protected]>

Author: Paolo Abeni

net/ipv4/inet_connection_sock.c

@@ -1040,12 +1040,26 @@ void inet_csk_prepare_forced_close(struct sock *sk)
 }
 EXPORT_SYMBOL(inet_csk_prepare_forced_close);
 
+static int inet_ulp_can_listen(const struct sock *sk)
+{
+	const struct inet_connection_sock *icsk = inet_csk(sk);
+
+	if (icsk->icsk_ulp_ops && !icsk->icsk_ulp_ops->clone)
+		return -EINVAL;
+
+	return 0;
+}
+
 int inet_csk_listen_start(struct sock *sk, int backlog)
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	struct inet_sock *inet = inet_sk(sk);
 	int err = -EADDRINUSE;
 
+	err = inet_ulp_can_listen(sk);
+	if (unlikely(err))
+		return err;
+
 	reqsk_queue_alloc(&icsk->icsk_accept_queue);
 
 	sk->sk_ack_backlog = 0;

net/ipv4/tcp_ulp.c

@@ -136,6 +136,10 @@ 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;
+	if (!ulp_ops->clone && sk->sk_state == TCP_LISTEN)
+		goto out_err;
+
 	err = ulp_ops->init(sk);
 	if (err)
 		goto out_err;