[PATCH net] hv_sock: add locking in the open/close/release code paths
From: Dexuan Cui <decui@microsoft.com>
Date: 2017-10-19 03:33:31
Without the patch, when hvs_open_connection() hasn't completely established a connection (e.g. it has changed sk->sk_state to SS_CONNECTED, but hasn't inserted the sock into the connected queue), vsock_stream_connect() may see the sk_state change and return the connection to the userspace, and next when the userspace closes the connection quickly, hvs_release() may not see the connection in the connected queue; finally hvs_open_connection() inserts the connection into the queue, but we won't be able to purge the connection for ever. Signed-off-by: Dexuan Cui <decui@microsoft.com> Cc: K. Y. Srinivasan <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <redacted> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Cathy Avery <redacted> Cc: Rolf Neugebauer <redacted> Cc: Marcelo Cerri <redacted> --- Please consider this for v4.14. net/vmw_vsock/hyperv_transport.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-)
diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
index 14ed5a3..e21991f 100644
--- a/net/vmw_vsock/hyperv_transport.c
+++ b/net/vmw_vsock/hyperv_transport.c@@ -310,11 +310,15 @@ static void hvs_close_connection(struct vmbus_channel *chan) struct sock *sk = get_per_channel_state(chan); struct vsock_sock *vsk = vsock_sk(sk); + lock_sock(sk); + sk->sk_state = SS_UNCONNECTED; sock_set_flag(sk, SOCK_DONE); vsk->peer_shutdown |= SEND_SHUTDOWN | RCV_SHUTDOWN; sk->sk_state_change(sk); + + release_sock(sk); } static void hvs_open_connection(struct vmbus_channel *chan)
@@ -344,6 +348,8 @@ static void hvs_open_connection(struct vmbus_channel *chan) if (!sk) return; + lock_sock(sk); + if ((conn_from_host && sk->sk_state != VSOCK_SS_LISTEN) || (!conn_from_host && sk->sk_state != SS_CONNECTING)) goto out;
@@ -395,9 +401,7 @@ static void hvs_open_connection(struct vmbus_channel *chan) vsock_insert_connected(vnew); - lock_sock(sk); vsock_enqueue_accept(sk, new); - release_sock(sk); } else { sk->sk_state = SS_CONNECTED; sk->sk_socket->state = SS_CONNECTED;
@@ -410,6 +414,8 @@ static void hvs_open_connection(struct vmbus_channel *chan) out: /* Release refcnt obtained when we called vsock_find_bound_socket() */ sock_put(sk); + + release_sock(sk); } static u32 hvs_get_local_cid(void)
@@ -476,13 +482,21 @@ static int hvs_shutdown(struct vsock_sock *vsk, int mode) static void hvs_release(struct vsock_sock *vsk) { + struct sock *sk = sk_vsock(vsk); struct hvsock *hvs = vsk->trans; - struct vmbus_channel *chan = hvs->chan; + struct vmbus_channel *chan; + lock_sock(sk); + + sk->sk_state = SS_DISCONNECTING; + vsock_remove_sock(vsk); + + release_sock(sk); + + chan = hvs->chan; if (chan) hvs_shutdown(vsk, RCV_SHUTDOWN | SEND_SHUTDOWN); - vsock_remove_sock(vsk); } static void hvs_destruct(struct vsock_sock *vsk)
--
2.7.4