From: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx> Sent: Wednesday, April 20, 2022 1:07 PM
>
> The function returns NULL if the ring buffer doesn't contain enough
> readable bytes to constitute a packet descriptor. The ring buffer's
> write_index is in memory which is shared with the Hyper-V host, an
> erroneous or malicious host could thus change its value and overturn
> the result of hvs_stream_has_data().
>
> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx>
> ---
> net/vmw_vsock/hyperv_transport.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
> index e111e13b66604..943352530936e 100644
> --- a/net/vmw_vsock/hyperv_transport.c
> +++ b/net/vmw_vsock/hyperv_transport.c
> @@ -603,6 +603,8 @@ static ssize_t hvs_stream_dequeue(struct vsock_sock *vsk,
> struct msghdr *msg,
>
> if (need_refill) {
> hvs->recv_desc = hv_pkt_iter_first_raw(hvs->chan);
> + if (!hvs->recv_desc)
> + return -ENOBUFS;
> ret = hvs_update_recv_data(hvs);
> if (ret)
> return ret;
> --
> 2.25.1
Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
