Re: [Qemu-devel] Re: [PATCH 1/5] virtio-net: Allow setting the MAC address via set_config

From: Avi Kivity <avi@redhat.com>
To: Jamie Lokier <jamie@shareable.org>
Cc: dlaor@redhat.com, qemu-devel@nongnu.org,
	Mark McLoughlin <markmc@redhat.com>, kvm <kvm@vger.kernel.org>
Subject: Re: [Qemu-devel] Re: [PATCH 1/5] virtio-net: Allow setting the MAC address via set_config
Date: Thu, 15 Jan 2009 15:41:48 +0200	[thread overview]
Message-ID: <496F3D1C.4020605@redhat.com> (raw)
In-Reply-To: <20090115131249.GD32368@shareable.org>

Jamie Lokier wrote:
> Dor Laor wrote:
>   
>> What I meant is that if we allow the guest to change his mac address, it 
>> can deliberately
>> change it to other hosts/guests mac and thus create networking problems.
>> Although guest can always mangle packets, maybe it worth enforcing these 
>> macs for the guest.
>>     
>
> Although it can create network problems, sometimes it is also wanted.
>
> I think if you want to restrict the guests's ability to break the
> network by changing its MAC, it would be appropriate to have an option
> to completely lock down the MAC so the guest can't change its MAC at all.
>   

I don't think locking down the MAC is very useful; the guest can still 
fake its IP address.

If the admin wants to lock down the guest, they should use netfilter 
(and live with the performance hit).

-- 
error compiling committee.c: too many arguments to function