lkml.org 
[lkml]   [2022]   [Apr]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/5] hv_sock: Copy packets sent by Hyper-V out of the ring buffer
On Wed, Apr 20, 2022 at 10:07:17PM +0200, Andrea Parri (Microsoft) wrote:
>Pointers to VMbus packets sent by Hyper-V are used by the hv_sock driver
>within the guest VM. Hyper-V can send packets with erroneous values or
>modify packet fields after they are processed by the guest. To defend
>against these scenarios, copy the incoming packet after validating its
>length and offset fields using hv_pkt_iter_{first,next}(). In this way,
>the packet can no longer be modified by the host.
>
>Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
>---
> net/vmw_vsock/hyperv_transport.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
>diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
>index 943352530936e..8c37d07017fc4 100644
>--- a/net/vmw_vsock/hyperv_transport.c
>+++ b/net/vmw_vsock/hyperv_transport.c
>@@ -78,6 +78,9 @@ struct hvs_send_buf {
> ALIGN((payload_len), 8) + \
> VMBUS_PKT_TRAILER_SIZE)
>
>+/* Upper bound on the size of a VMbus packet for hv_sock */
>+#define HVS_MAX_PKT_SIZE HVS_PKT_LEN(HVS_MTU_SIZE)
>+
> union hvs_service_id {
> guid_t srv_id;
>
>@@ -378,6 +381,8 @@ static void hvs_open_connection(struct vmbus_channel *chan)
> rcvbuf = ALIGN(rcvbuf, HV_HYP_PAGE_SIZE);
> }
>
>+ chan->max_pkt_size = HVS_MAX_PKT_SIZE;
>+

premise, I don't know HyperV channels :-(

Is this change necessary to use hv_pkt_iter_first() instead of
hv_pkt_iter_first_raw()?

If yes, then please mention that you set this value in the commit
message, otherwise maybe better to have a separate patch.

Thanks,
Stefano

> ret = vmbus_open(chan, sndbuf, rcvbuf, NULL, 0, hvs_channel_cb,
> conn_from_host ? new : sk);
> if (ret != 0) {
>@@ -602,7 +607,7 @@ static ssize_t hvs_stream_dequeue(struct vsock_sock *vsk, struct msghdr *msg,
> return -EOPNOTSUPP;
>
> if (need_refill) {
>- hvs->recv_desc = hv_pkt_iter_first_raw(hvs->chan);
>+ hvs->recv_desc = hv_pkt_iter_first(hvs->chan);
> if (!hvs->recv_desc)
> return -ENOBUFS;
> ret = hvs_update_recv_data(hvs);
>@@ -618,7 +623,7 @@ static ssize_t hvs_stream_dequeue(struct vsock_sock *vsk, struct msghdr *msg,
>
> hvs->recv_data_len -= to_read;
> if (hvs->recv_data_len == 0) {
>- hvs->recv_desc = hv_pkt_iter_next_raw(hvs->chan, hvs->recv_desc);
>+ hvs->recv_desc = hv_pkt_iter_next(hvs->chan, hvs->recv_desc);
> if (hvs->recv_desc) {
> ret = hvs_update_recv_data(hvs);
> if (ret)
>--
>2.25.1
>

\
 
 \ /
  Last update: 2022-04-21 15:59    [W:0.109 / U:0.832 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site