Commit 2c02d41d authored by Paolo Abeni's avatar Paolo Abeni Committed by Jakub Kicinski
Browse files

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: 734942cc ("tcp: ULP infrastructure")
Reported-by: default avatarslipper <slipper.alive@gmail.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/4b80c3d1dbe3d0ab072f80450c202d9bc88b4b03.1672740602.git.pabeni@redhat.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 5401c3e0

net/ipv4/inet_connection_sock.c

+14 −0
Original line number Diff line number Diff line
@@ -1200,12 +1200,26 @@ 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)

{

	struct inet_connection_sock *icsk = inet_csk(sk);

	struct inet_sock *inet = inet_sk(sk);

	int err;



	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

+4 −0
Original line number Diff line number Diff line
@@ -139,6 +139,10 @@ static int __tcp_set_ulp(struct sock *sk, const struct tcp_ulp_ops *ulp_ops) 
	if (sk->sk_socket)

		clear_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags);



	err = -EINVAL;

	if (!ulp_ops->clone && sk->sk_state == TCP_LISTEN)

		goto out_err;



	err = ulp_ops->init(sk);

	if (err)

		goto out_err;