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@xxxxxxxxxx>
---
net/vmw_vsock/virtio_transport_common.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index db127a69f5c3..481f7f8a1655 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -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
--
2.21.0
