Commit e381d2b4 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'vsock-virtio-make-the-credit-mechanism-more-robust' 



Stefano Garzarella says:

====================
vsock/virtio: make the credit mechanism more robust

This series makes the credit mechanism implemented in the
virtio-vsock devices more robust.
Patch 1 sends an update to the remote peer when the buf_alloc
change.
Patch 2 prevents a malicious peer (especially the guest) can
consume all the memory of the other peer, discarding packets
when the credit available is not respected.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 2e978795 ae6fcfbf

net/vmw_vsock/virtio_transport_common.c

+14 −3
Original line number Diff line number Diff line
@@ -204,10 +204,14 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk, 
	return virtio_transport_get_ops()->send_pkt(pkt);

}



static void virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs,

static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs,

					struct virtio_vsock_pkt *pkt)

{

	if (vvs->rx_bytes + pkt->len > vvs->buf_alloc)

		return false;



	vvs->rx_bytes += pkt->len;

	return true;

}



static void virtio_transport_dec_rx_pkt(struct virtio_vsock_sock *vvs,
@@ -458,6 +462,9 @@ void virtio_transport_set_buffer_size(struct vsock_sock *vsk, u64 val) 
		vvs->buf_size_max = val;

	vvs->buf_size = val;

	vvs->buf_alloc = val;



	virtio_transport_send_credit_update(vsk, VIRTIO_VSOCK_TYPE_STREAM,

					    NULL);

}

EXPORT_SYMBOL_GPL(virtio_transport_set_buffer_size);
@@ -876,14 +883,18 @@ virtio_transport_recv_enqueue(struct vsock_sock *vsk, 
			      struct virtio_vsock_pkt *pkt)

{

	struct virtio_vsock_sock *vvs = vsk->trans;

	bool free_pkt = false;

	bool can_enqueue, free_pkt = false;



	pkt->len = le32_to_cpu(pkt->hdr.len);

	pkt->off = 0;



	spin_lock_bh(&vvs->rx_lock);



	virtio_transport_inc_rx_pkt(vvs, pkt);

	can_enqueue = virtio_transport_inc_rx_pkt(vvs, pkt);

	if (!can_enqueue) {

		free_pkt = true;

		goto out;

	}



	/* Try to copy small packets into the buffer of last packet queued,

	 * to avoid wasting memory queueing the entire buffer with a small

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