Re: [Xen-devel] Academic Project

[Christian Leber <christian@xxxxxxxx>]

On Wed, Mar 04, 2009 at 08:25:49AM +0530, dinesh chandrasekaran wrote:

Hi dinesh

>    > That implies the protection hardware is not controlled by the dom0 and
>    > there is another more secure way for the administration of it and second
>    > that the dom0 can't do anything.
> 
>    Absolutely. You are correct.

Ok, so how do you plan to do this and why is this supposed to be more
secure?

>    I guess the domain scheduling is done by the VMM and not by dom0?
>    Through VMM Hooks, the VMM is made to inform the device about the domain
>    scheduled to run.
>    So dom0 cannot claim to be any domU.

I'm not really sure, but i think the dom0 can access the complete system
memory. If not, then it controls at least some hardware that can do DMA
and can this way access all the memory.

-> dom0 can write/read all memory -> it can do anything

>    > furthermore the dom0 should also be able to overwrite the xen kernel.
> 
>    Can you throw some lights on the above "overwriting the xen kernel by
>    dom0"?

A compromised dom0 could just replace the xen kernel/hypervisor on disk and/or 
in
memory.

Your idea just has so many problems, like what are you doing to do about disk 
i/o?


Christian


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