| Message ID | 20220427131225.3785-3-parri.andrea@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | hv_sock: Hardening changes | expand |
On Wed, Apr 27, 2022 at 03:12:22PM +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}(). Use >HVS_PKT_LEN(HVS_MTU_SIZE) to initialize the buffer which holds the >copies of the incoming packets. In this way, the packet can no longer >be modified by the host. > >Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> >Reviewed-by: Michael Kelley <mikelley@microsoft.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; >+ > 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 > Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
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; + 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)
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}(). Use HVS_PKT_LEN(HVS_MTU_SIZE) to initialize the buffer which holds the copies of the incoming packets. In this way, the packet can no longer be modified by the host. Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> --- net/vmw_vsock/hyperv_transport.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)