Re: [RFC][PATCH 00/01]qemu VM entrypoints

David Windsor
2007-07-21T06:53:03Z

On 7/21/07 2:21 AM, "Avi Kivity" <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org> wrote:

> Anthony Liguori wrote:
>> James Morris wrote:
>>
>>> On Fri, 20 Jul 2007, Daniel P. Berrange wrote:
>>>
>>>
>>>
>>>> It could be - if your put the policy at the control API layer instead of
>>>> in QEMU itself.
>>>>
>>>>
>>> Then you can bypass MAC security by invoking qemu directly.
>>>
>>>
>>
>> You can bypass MAC security by writing your own binary that uses the KVM
>> kernel interfaces.
>>
>>
>
> I guess modifying qemu makes sense if the modification gives you *more*
> permissions.
>
> i.e. you start out just with the ability to access the disk image, and
> then you transition to a new domain that allows you to access some network.
>
>
> Is that what is intended here?

The intent here is to provide some mechanism for a policy-driven transition
to occur when loading a virtual disk. So, an administrator would write
policy for say, a topsecret_vm_t domain, in which the top secret VM can run.
All access requests from this VM would have a source type of topsecret_vm_t
on the host machine. The virtual disk, labeled perhaps as topsecret_disk_t,
would need to be authorized in policy to be an entrypoint into the
topsecret_vm_t domain. This patch proposes a mechanism that allows us to
provide policy driven controls both over which files can be used as a disk
image, and to which domain a qemu process will transition after loading the
disk image.

Originally, I thought qemu was the proper place for this type of an
enforcement hook, but libvirt may be more appropriate because qemu could be
launched with a different security context if loading a virtual disk, rather
than having qemu set up the security context of the VM. Thoughts?