From: Wei Wang wei.w.wang@intel.com
[ Upstream commit 1db8f5fc2e5c66a5c51e1f6488e0ba7d45c29ae4 ]
The VMADDR_CID_ANY flag used by a socket means that the socket isn't bound to any specific CID. For example, a host vsock server may want to be bound with VMADDR_CID_ANY, so that a guest vsock client can connect to the host server with CID=VMADDR_CID_HOST (i.e. 2), and meanwhile, a host vsock client can connect to the same local server with CID=VMADDR_CID_LOCAL (i.e. 1).
The current implementation sets the destination socket's svm_cid to a fixed CID value after the first client's connection, which isn't an expected operation. For example, if the guest client first connects to the host server, the server's svm_cid gets set to VMADDR_CID_HOST, then other host clients won't be able to connect to the server anymore.
Reproduce steps: 1. Run the host server: socat VSOCK-LISTEN:1234,fork - 2. Run a guest client to connect to the host server: socat - VSOCK-CONNECT:2:1234 3. Run a host client to connect to the host server: socat - VSOCK-CONNECT:1:1234
Without this patch, step 3. above fails to connect, and socat complains "socat[1720] E connect(5, AF=40 cid:1 port:1234, 16): Connection reset by peer". With this patch, the above works well.
Fixes: c0cfa2d8a788 ("vsock: add multi-transports support") Signed-off-by: Wei Wang wei.w.wang@intel.com Link: https://lore.kernel.org/r/20211126011823.1760-1-wei.w.wang@intel.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Reviewed-by: Stefano Garzarella sgarzare@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/vmw_vsock/virtio_transport_common.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index 59ee1be5a6dd3..ec2c2afbf0d06 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -1299,7 +1299,8 @@ void virtio_transport_recv_pkt(struct virtio_transport *t, space_available = virtio_transport_space_update(sk, pkt);
/* Update CID in case it has changed after a transport reset event */ - vsk->local_addr.svm_cid = dst.svm_cid; + if (vsk->local_addr.svm_cid != VMADDR_CID_ANY) + vsk->local_addr.svm_cid = dst.svm_cid;
if (space_available) sk->sk_write_space(sk);