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: 734942cc4ea6 ("tcp: ULP infrastructure")
Reported-by: slipper <slipper.alive@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/4b80c3d1dbe3d0ab072f80450c202d9bc88b4b03.1672740602.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 848ffc3e0239c345d6a1f119a70c5909e8da28e6..d1f837579398302f2b3729163c36b12b34e523e0 100644 (file)
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -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;

diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c
index 9ae50b1bd8444163acedd6f8df70afbb3583bc4b..05b6077b9f2c3543a5aaeed72d6a5e7b99edd1ec 100644 (file)
--- a/net/ipv4/tcp_ulp.c
+++ b/net/ipv4/tcp_ulp.c
@@ -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;