Re: [Qemu-devel] [RFC 4/4] virtio-net: Add MTU feature support

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 09/16/2016 12:16 AM, Paolo Bonzini wrote:
>
>
> On 06/09/2016 18:11, Maxime Coquelin wrote:
>>      VirtIONet *n = VIRTIO_NET(vdev);
>>      struct virtio_net_config netcfg;
>>
>> +    if (virtio_vdev_has_feature(vdev, VIRTIO_NET_F_MTU)) {
>> +        virtio_stw_p(vdev, &netcfg.mtu, n->mtu);
>> +    }
>
> This write needs to be unconditional, otherwise you are leaking a few
> bytes of QEMU's stack (corresponding to netcfg.mtu) to the guest.

Right, thanks for pointing this out. I'll make it unconditional.

Maxime

> Paolo
>
>>      virtio_stw_p(vdev, &netcfg.status, n->status);
>>      virtio_stw_p(vdev, &netcfg.max_virtqueue_pairs, n->max_queues);
>>      memcpy(netcfg.mac, n->mac, ETH_ALEN);