[PATCH 4.19 096/114] vhost/vsock: accept only packets with the right dst_cid

Greg Kroah-Hartman
2020-01-02T22:22:29Z

From: Stefano Garzarella <sgarzare@redhat.com>

[ Upstream commit 8a3cc29c316c17de590e3ff8b59f3d6cbfd37b0a ]

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/vhost/vsock.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -436,7 +436,9 @@ static void vhost_vsock_handle_tx_kick(s
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(pkt);
else
virtio_transport_free_pkt(pkt);