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From: Paolo Bonzini <pbonzini@redhat.com>
To: Maxime Coquelin <maxime.coquelin@redhat.com>,
	mst@redhat.com, qemu-devel@nongnu.org
Cc: jasowang@redhat.com, Aaron Conole <aconole@redhat.com>
Subject: Re: [Qemu-devel] [RFC 4/4] virtio-net: Add MTU feature support
Date: Fri, 16 Sep 2016 00:16:29 +0200	[thread overview]
Message-ID: <2e349a9d-8609-b3d6-6681-537c4362c367@redhat.com> (raw)
In-Reply-To: <1473178269-16718-5-git-send-email-maxime.coquelin@redhat.com>



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.

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);

  reply	other threads:[~2016-09-15 22:17 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-06 16:11 [Qemu-devel] [RFC 0/4] virtio-net: Add support to MTU feature Maxime Coquelin
2016-09-06 16:11 ` [Qemu-devel] [RFC 1/4] virtio-net: reuse MTU related bits from Linux header Maxime Coquelin
2016-09-06 16:11 ` [Qemu-devel] [RFC 2/4] vhost-user: Add new protocol feature MTU Maxime Coquelin
2016-09-06 16:11 ` [Qemu-devel] [RFC 3/4] vhost-net: Add new MTU feature support Maxime Coquelin
2016-09-06 16:11 ` [Qemu-devel] [RFC 4/4] virtio-net: Add " Maxime Coquelin
2016-09-15 22:16   ` Paolo Bonzini [this message]
2016-09-16  6:36     ` Maxime Coquelin

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