Re: [RFC] Unify KVM kernel-space and user-space code into a single project

Joerg Roedel
2010-03-24T15:37:47Z

On Wed, Mar 24, 2010 at 03:26:53PM +0000, Daniel P. Berrange wrote:
> On Wed, Mar 24, 2010 at 04:01:37PM +0100, Joerg Roedel wrote:
> > >> An approach like: "The files are owned and only readable by the same
> > >> user that started the vm." might be a good start. So a user can measure
> > >> its own guests and root can measure all of them.
> > >
> > > That's not how sVirt works. sVirt isolates a user's VMs from each
> > > other, so if a guest breaks into qemu it can't break into other guests
> > > owned by the same user.
> >
> > If a vm breaks into qemu it can access the host file system which is the
> > bigger problem. In this case there is no isolation anymore. From that
> > context it can even kill other VMs of the same user independent of a
> > hypothetical /sys/kvm/.
>
> No it can't. With sVirt every single VM has a custom security label and
> the policy only allows it access to disks / files with a matching label,
> and prevents it attacking any other VMs or processes on the host. THis
> confines the scope of any exploit in QEMU to those resources the admin
> has explicitly assigned to the guest.

Even better. So a guest which breaks out can't even access its own
/sys/kvm/ directory. Perfect, it doesn't need that access anyway.

Joerg