Re: [PATCH] vhost/vsock: accept only packets with the right dst_cid

Michael S. Tsirkin
2019-12-11T16:03:19Z

On Fri, Dec 06, 2019 at 03:39:12PM +0100, Stefano Garzarella wrote:
> 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@redhat.com>

Stefano can you clarify the impact pls?
E.g. is this needed on stable? Etc.

Thanks!

> ---
> 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