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vhost/vsock: fix reset orphans race with close timeout

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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>
This commit is contained in:
Stefan Hajnoczi 2018-12-06 19:14:34 +00:00 committed by Michael S. Tsirkin
parent 2595646791
commit c38f57da42
1 changed files with 15 additions and 7 deletions
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22
drivers/vhost/vsock.c
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@ -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)