From c38f57da428b033f2721b611d84b1f40bde674a8 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Thu, 6 Dec 2018 19:14:34 +0000 Subject: vhost/vsock: fix reset orphans race with close timeout 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 Cc: Graham Whaley Signed-off-by: Stefan Hajnoczi Signed-off-by: Michael S. Tsirkin --- drivers/vhost/vsock.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c index 34bc3ab40c6d..731e2ea2aeca 100644 --- a/drivers/vhost/vsock.c +++ b/drivers/vhost/vsock.c @@ -563,13 +563,21 @@ static void vhost_vsock_reset_orphans(struct sock *sk) * executing. */ - if (!vhost_vsock_get(vsk->remote_addr.svm_cid)) { - 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); - } + /* 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) -- cgit v1.2.3