Commit 50dc13e2 authored Dec 06, 2018 by Stefan Hajnoczi Committed by Greg Kroah-Hartman Dec 21, 2018

vhost/vsock: fix reset orphans race with close timeout



[ Upstream commit c38f57da428b033f2721b611d84b1f40bde674a8 ]

If a local process has closed a connected socket and hasn't received a
RST packet yet, then the socket remains in the table until a timeout
expires.

When a vhost_vsock instance is released with the timeout still pending,
the socket is never freed because vhost_vsock has already set the
SOCK_DONE flag.

Check if the close timer is pending and let it close the socket.  This
prevents the race which can leak sockets.

Reported-by: Maximilian Riemensberger <riemensberger@cadami.net>
Cc: Graham Whaley <graham.whaley@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent b5a8028c

drivers/vhost/vsock.c

+15 −7

Original line number	Diff line number	Diff line
		@@ -563,14 +563,22 @@ static void vhost_vsock_reset_orphans(struct sock *sk)
		* executing.
		*/

		if (!vhost_vsock_get(vsk->remote_addr.svm_cid)) {
		/* If the peer is still valid, no need to reset connection */
		if (vhost_vsock_get(vsk->remote_addr.svm_cid))
		return;

		/* If the close timeout is pending, let it expire. This avoids races
		* with the timeout callback.
		*/
		if (vsk->close_work_scheduled)
		return;

		sock_set_flag(sk, SOCK_DONE);
		vsk->peer_shutdown = SHUTDOWN_MASK;
		sk->sk_state = SS_UNCONNECTED;
		sk->sk_err = ECONNRESET;
		sk->sk_error_report(sk);
		}
		}

		static int vhost_vsock_dev_release(struct inode inode, struct file file)
		{