On Mon, May 18, 2020 at 11:37:20PM +0300, Nikos Dragazis wrote:
> Signed-off-by: Nikos Dragazis <ndraga...@arrikto.com>
> ---
> virtio-vhost-user.tex | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/virtio-vhost-user.tex b/virtio-vhost-user.tex
> index a673526..328baec 100644
> --- a/virtio-vhost-user.tex
> +++ b/virtio-vhost-user.tex
> @@ -142,10 +142,15 @@ \subsubsection{Device Operation: RX/TX
> Queues}\label{sec:Device Types / Vhost-us
> message that is too large for an rxq buffer, then DEVICE_NEEDS_RESET is set
> and
> the driver must reset the device.
>
> -File descriptor passing is handled differently by the vhost-user device
> -backend. When a message is received that carries one or more file
> descriptors
> -according to the vhost-user protocol, additional device resources become
> -available to the driver.
> +File descriptor passing is handled differently by the vhost-user device
> backend.
> +When a master-initiated message is received that carries one or more file
> +descriptors according to the vhost-user protocol, additional device resources
> +become available to the driver.
> +
> +On the contrary, the slave cannot pass file descriptors to the master. For
> this
> +reason, the vhost-user device backend MUST be intercepting the slave's reply
> to
> +the VHOST_USER_GET_PROTOCOL_FEATURES vhost-user message and clearing these
> +feature bits that allow the slave to send messages that pass file
> descriptors.Please be specific about which vhost-user protocol bits are not supported. Why does the virtio-vhost-user device implementation need to silently clear those feature bits? Is there a security impact or some other reason why the VIRTIO spec should specify this behavior? Stefan
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