Re: [Qemu-devel] [PATCH v3 5/6] docs: start a document to describe D-Bus usage

[Marc-André Lureau]

Hi

On Tue, Sep 17, 2019 at 12:12 PM Dr. David Alan Gilbert
<address@hidden> wrote:
>
> * Marc-André Lureau (address@hidden) wrote:
> > Hi
> >
> > On Mon, Sep 16, 2019 at 5:15 PM Dr. David Alan Gilbert
> > <address@hidden> wrote:
> > >
> > > * Marc-André Lureau (address@hidden) wrote:
> > > > Hi
> > > >
> > > > On Mon, Sep 16, 2019 at 2:02 PM Dr. David Alan Gilbert
> > > > <address@hidden> wrote:
> > > > >
> > > > > (Copying in Stefan since he was looking at DBus for virtiofs)
> > > > >
> > > > > * Marc-André Lureau (address@hidden) wrote:
> > > > > > Signed-off-by: Marc-André Lureau <address@hidden>
>
> <snip>
>
> > > > Do you have a specific question we can answer or guide for qemu? Is
> > > > there something we have to document or implement?
> > > >
> > > > Since qemu is not managing the extra processes or applying policies, I
> > > > don't know what else could be done. From qemu pov, it can rely on
> > > > management layer to trust the bus and the helpers, similar to trusting
> > > > the system in general.
> > >
> > > Well pretty much the same questions I asked in the discussion on v2;
> > > what is the supported configuration to ensure that one helper that's
> > > been compromised can't attack the others and qemu?
> >
> > I thought I gave the answer to that question above. What is missing? I
> > don't think one can generalize it here, it will be a case by case for
> > each helper, how they interact with each other and qemu.
>
> I think we need an example of how to lock it down; i.e. to allow a
> helper to provide migration data but not to be able to speak to other
> helpers.
>

That's the example policy I gave for dbus-dameon. Only qemu user can
talk to Helper1 (for ex, a helper migration interface). Only
qemu-helper user can claim Helper1.

You could have additionally other ways: selinux policy, p2p helpers
SCM credentials checks, or other methods.



-- 
Marc-André Lureau