| Message ID | 20181206191434.15448-1-stefanha@redhat.com |
|---|---|
| State | Not Applicable, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | vhost/vsock: fix reset orphans race with close timeout | expand |
From: Stefan Hajnoczi <stefanha@redhat.com> Date: Thu, 6 Dec 2018 19:14:34 +0000 > 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> Michael please review, and let me know if you want me to apply this directly and queue it up for -stable.
On Sat, Dec 08, 2018 at 09:25:44PM -0800, David Miller wrote: > From: Stefan Hajnoczi <stefanha@redhat.com> > Date: Thu, 6 Dec 2018 19:14:34 +0000 > > > 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> > > Michael please review, and let me know if you want me to apply this > directly and queue it up for -stable. I sent this to Linus already.
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)
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> --- drivers/vhost/vsock.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-)