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vsock/virtio: discard packets if credit is not respected 

If the remote peer doesn't respect the credit information
(buf_alloc, fwd_cnt), sending more data than it can send,
we should drop the packets to prevent a malicious peer
from using all of our memory.

This is patch follows the VIRTIO spec: "VIRTIO_VSOCK_OP_RW data
packets MUST only be transmitted when the peer has sufficient
free buffer space for the payload"

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
alistair/sunxi64-5.4-dsi
Stefano Garzarella 2019-10-17 14:44:03 +02:00 committed by David S. Miller
parent ec3359b685
commit ae6fcfbf5f
1 changed files with 11 additions and 3 deletions
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14
net/vmw_vsock/virtio_transport_common.c
View File

@ -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,
@ -879,14 +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