RE: [Xense-devel] Shype/ACM for HVM guest.

[Stefan Berger <stefanb@xxxxxxxxxx>]

"Praveen Kushwaha" <praveen.kushwaha@xxxxxxxxxxx>
wrote on 04/04/2007 02:53:06 AM:

> Hi,
>           Yes,  the
Chinese wall policy hook is there for checking 
> whether the HVM guest is allowed to run or not. 
>            But
the my question is that suppose the HVM guest wants 
> to do some IO (disk access, printer etc). Then for the communicationwith
the 
>             VMM,
VMExit will happen ( A transition from the HVM 
> guest to VMM is done). Then, Where the shype/ACM put hooks in order
> to have control over 
>             resources(IO
devices) for the HVM guests?

IO devices that are connected to the HVM and whose
parameters are provided through the VM configuration can be checked against
their labeling once a domain is started using xend. Currently for HVMs
only disk entries are checked. More will need to be added in this area
in the future.

>             As
it puts hooks on hypercalls in case of paravirtualization.
>             What
shype/ACM does in case of full virtualization?

In case of full virutalization, the hooks on the hypercalls
for grant tables and event channels are not being used. So oin HVM case,
checks are only done during startup of a virtual machine.

Stefan

>  
> Thanks,
> Praveen Kushwaha
>  
>  
>              
 
>  
> 
> From: Stefan Berger [mailto:stefanb@xxxxxxxxxx] 
> Sent: Tuesday, April 03, 2007 8:29 PM
> To: Praveen Kushwaha
> Cc: xense-devel@xxxxxxxxxxxxxxxxxxx; xense-devel-bounces@xxxxxxxxxxxxxxxxxxx
> Subject: RE: [Xense-devel] Shype/ACM for HVM guest.
>  
> 
> "Praveen Kushwaha" <praveen.kushwaha@xxxxxxxxxxx>
wrote on 
> 04/03/2007 05:42:56 AM:
> 
> > Hi, 
> >              Yes that is fine
if the paravirtualized drivers are 
> > used in HVM then we can put hooks on that. But it is different
case,
> > how actually shype/ACM works in case of VMExit/VMEntry. 
> >               Since in case
of VMExit/VMEntry there are no 
> > hypercalls, then how sHype/ACM implements security. 
> >               I mean to ask
that how sHype/ACM works in case of HVM guest. 
> 
> In case of an HVM guest you would have the Chinese Wall Policy hooks
> checking whether the HVM guest is allowed to run with its current
VM label. 
> Access to resources such as image files is also checked when a 
> virtual machine is started up. 
> 
>    Stefan 
> 
> 
> >   
> > Thanks, 
> > Praveen Kushwaha 
> >     
> >               
> >               
> >   
> >   
> >   
> > 
> > From: Stefan Berger [mailto:stefanb@xxxxxxxxxx] 
> > Sent: Monday, April 02, 2007 7:19 PM
> > To: Praveen Kushwaha
> > Cc: xense-devel@xxxxxxxxxxxxxxxxxxx; xense-devel-bounces@xxxxxxxxxxxxxxxxxxx
> > Subject: Re: [Xense-devel] Shype/ACM for HVM guest. 
> >   
> > 
> > xense-devel-bounces@xxxxxxxxxxxxxxxxxxx wrote on 04/02/2007 05:40:39
AM:
> > 
> > > Hi, 
> > >             Does Shype/ACM
architecture for implementing security in
> > > xen supports HVM guest also?  I mean to say that, as
per my 
> > 
> > HVM guests are supported in so far that the configuration of
an HVM 
> > is checked when the VM is started. This is done in xend where
> > resource assignments (disk access)  are validated. 
> > 
> > > knowledge in xen 3.0.4         shype/ACM
is implemented. Does this 
> > > shype/ACM work also for the HVM (windows) guest? 
> > >               As per
my understanding shype/ACM puts hook on 
> > > hypercalls from the hypervisor, and consult with the ACM.
But in 
> > > case of full virtualization, hypervisor does not have hypercalls
to 
> > > communicate with HVM guest. There is VMEntry/VMExit for
> > 
> > This is correct. Though, if paravirtualized drivers are used
in an 
> > HVM, also they will need to go through the hooks for grant table
> > access and event channels. 
> > 
> >    Stefan 
> > 
> > 
> > > communication, in which guest state and host state are saved.
 Since
> > > there are no hypercalls  in case of full virtualization
then how the
> > > actually shype/ACM works. Where does it put hooks? Or is
there any 
> > > other mechanism through which it implements security in
HVM guest. 
> > >       If any one has information regarding
it  please reply. 
> > >   
> > > Thanks, 
> > > Praveen Kushwaha 
> > >   
> > >         
> > >   
> > >  _______________________________________________
> > > Xense-devel mailing list
> > > Xense-devel@xxxxxxxxxxxxxxxxxxx
> > > http://lists.xensource.com/xense-devel
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