vsock/virtio: discard packets if the transport changes

If the socket has been de-assigned or assigned to another transport,
we must discard any packets received because they are not expected
and would cause issues when we access vsk->transport.

A possible scenario is described by Hyunwoo Kim in the attached link,
where after a first connect() interrupted by a signal, and a second
connect() failed, we can find `vsk->transport` at NULL, leading to a
NULL pointer dereference.

Fixes: c0cfa2d8a7 ("vsock: add multi-transports support")
Cc: stable@vger.kernel.org
Reported-by: Hyunwoo Kim <v4bel@theori.io>
Reported-by: Wongi Lee <qwerty@theori.io>
Closes: https://lore.kernel.org/netdev/Z2LvdTTQR7dBmPb5@v4bel-B760M-AORUS-ELITE-AX/
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Hyunwoo Kim <v4bel@theori.io>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Stefano Garzarella 2025-01-10 09:35:07 +01:00 committed by Paolo Abeni
parent 0865b9fdb2
commit 2cb7c756f6

View file

@ -1628,8 +1628,11 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
lock_sock(sk);
/* Check if sk has been closed before lock_sock */
if (sock_flag(sk, SOCK_DONE)) {
/* Check if sk has been closed or assigned to another transport before
* lock_sock (note: listener sockets are not assigned to any transport)
*/
if (sock_flag(sk, SOCK_DONE) ||
(sk->sk_state != TCP_LISTEN && vsk->transport != &t->transport)) {
(void)virtio_transport_reset_no_sock(t, skb);
release_sock(sk);
sock_put(sk);