netdev - [PATCH] vhost/vsock: accept only packets with the right dst

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Message-Id: <20191206143912.153583-1-sgarzare@redhat.com>
Date:   Fri,  6 Dec 2019 15:39:12 +0100
From:   Stefano Garzarella <sgarzare@...hat.com>
To:     virtualization@...ts.linux-foundation.org
Cc:     Stefano Garzarella <sgarzare@...hat.com>,
        Stefan Hajnoczi <stefanha@...hat.com>,
        Jason Wang <jasowang@...hat.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        "Michael S. Tsirkin" <mst@...hat.com>
Subject: [PATCH] vhost/vsock: accept only packets with the right dst_cid

When we receive a new packet from the guest, we check if the
src_cid is correct, but we forgot to check the dst_cid.

The host should accept only packets where dst_cid is
equal to the host CID.

Signed-off-by: Stefano Garzarella <sgarzare@...hat.com>
---
 drivers/vhost/vsock.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 50de0642dea6..c2d7d57e98cf 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -480,7 +480,9 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
 		virtio_transport_deliver_tap_pkt(pkt);
 
 		/* Only accept correctly addressed packets */
-		if (le64_to_cpu(pkt->hdr.src_cid) == vsock->guest_cid)
+		if (le64_to_cpu(pkt->hdr.src_cid) == vsock->guest_cid &&
+		    le64_to_cpu(pkt->hdr.dst_cid) ==
+		    vhost_transport_get_local_cid())
 			virtio_transport_recv_pkt(&vhost_transport, pkt);
 		else
 			virtio_transport_free_pkt(pkt);
-- 
2.23.0