Subject: [PATCH AUTOSEL 5.13 145/189] vsock: notify server to shutdown when client has pending signal

From: Sasha Levin <[email-masked]>
Date: Tue, 6 Jul 2021 07:13:25 -0400

From: "Longpeng(Mike)" <[email-masked]>

[ 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 <[email-masked]>
Cc: Jakub Kicinski <[email-masked]>
Cc: Jorgen Hansen <[email-masked]>
Cc: Norbert Slusarek <[email-masked]>
Cc: Andra Paraschiv <[email-masked]>
Cc: Colin Ian King <[email-masked]>
Cc: David Brazdil <[email-masked]>
Cc: Alexander Popov <[email-masked]>
Suggested-by: Stefano Garzarella <[email-masked]>
Link: https://lkml.org/lkml/2021/5/17/418
Signed-off-by: lixianming <[email-masked]>
Signed-off-by: Longpeng(Mike) <[email-masked]>
Reviewed-by: Stefano Garzarella <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 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 92a72f0e0d94..ae11311807fd 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