[PATCH 5.12 113/242] vsock: notify server to shutdown when client has pending signal

[Greg Kroah-Hartman]

From: Longpeng(Mike) <longpeng2@xxxxxxxxxx>

[ Upstream commit c7ff9cff70601ea19245d997bb977344663434c7 ]

The client's sk_state will be set to TCP_ESTABLISHED if the server
replay the client's connect request.

However, if the client has pending signal, its sk_state will be set
to TCP_CLOSE without notify the server, so the server will hold the
corrupt connection.

            client                        server

1. sk_state=TCP_SYN_SENT         |
2. call ->connect()              |
3. wait reply                    |
                                 | 4. sk_state=TCP_ESTABLISHED
                                 | 5. insert to connected list
                                 | 6. reply to the client
7. sk_state=TCP_ESTABLISHED      |
8. insert to connected list      |
9. *signal pending* <--------------------- the user kill client
10. sk_state=TCP_CLOSE           |
client is exiting...             |
11. call ->release()             |
     virtio_transport_close
      if (!(sk->sk_state == TCP_ESTABLISHED ||
	      sk->sk_state == TCP_CLOSING))
		return true; *return at here, the server cannot notice the connection is corrupt*

So the client should notify the peer in this case.

Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
Cc: Jorgen Hansen <jhansen@xxxxxxxxxx>
Cc: Norbert Slusarek <nslusarek@xxxxxxx>
Cc: Andra Paraschiv <andraprs@xxxxxxxxxx>
Cc: Colin Ian King <colin.king@xxxxxxxxxxxxx>
Cc: David Brazdil <dbrazdil@xxxxxxxxxx>
Cc: Alexander Popov <alex.popov@xxxxxxxxx>
Suggested-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
Link: https://lkml.org/lkml/2021/5/17/418
Signed-off-by: lixianming <lixianming5@xxxxxxxxxx>
Signed-off-by: Longpeng(Mike) <longpeng2@xxxxxxxxxx>
Reviewed-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/vmw_vsock/af_vsock.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index bc7fb9bf3351..2a82fbf32ccc 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1369,7 +1369,7 @@ static int vsock_stream_connect(struct socket *sock, struct sockaddr *addr,
 
 		if (signal_pending(current)) {
 			err = sock_intr_errno(timeout);
-			sk->sk_state = TCP_CLOSE;
+			sk->sk_state = sk->sk_state == TCP_ESTABLISHED ? TCP_CLOSING : TCP_CLOSE;
 			sock->state = SS_UNCONNECTED;
 			vsock_transport_cancel_pkt(vsk);
 			goto out_wait;
-- 
2.30.2