Re: [PATCH v2] vsock: notify server to shutdown when client has pending signal

From: Stefano Garzarella
Date: Mon Jun 21 2021 - 06:02:37 EST


On Mon, Jun 21, 2021 at 02:26:01PM +0800, Longpeng(Mike) wrote:
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>
---
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 92a72f0..ae11311 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;
--
1.8.3.1


Reviewed-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>