Re: Guix and remote trust

[Josh Marshall]

But couldn't a theoretically compromised machine use a VM  to obtain the
valid hashes?

On Fri, Dec 13, 2019, 07:51 zimoun <address@hidden> wrote:

> Hi Pierre,
>
> On Fri, 13 Dec 2019 at 13:24, Pierre Neidhardt <address@hidden> wrote:
>
> > >  1. check the integrity on the balaitou machine by running "guix gc
> --verify"
> >
> > I'm not sure this works because if `guix' itself is compromised,
> > `guix gc --verify' becomes irrelevant.  Or is there another way?
>
> Ok. And so?
> It means that some hashes will differ between the hashes on aneto (you
> trust) and balaitou (compromised).
> It is not possible to "guix gc --verify" two machines and to obtain
> all the same hashes. Or it means that the "attacker" is doing
> hash-collision...
>
>
> > >  2. publish the store of aneto with "guix publish"
> >
> > And then install packages from balaitou?  But if Balaitou's "guix" is
> > compromised, it does not matter that the substitute server is trusted.
>
> Your point is to check if balaitou is compromised, right?
> The goal of "guix publish" is not to install or serve substitutes, it
> is just to publicly expose what we trust.
> Whatever from where comes from the binary (substitutes, local build, etc.).
>
>
> > >  3. challenge the store of balaitou against the store of aneto with
> > > "guix challenge"
> >
> > This seems like a good option.  In particular, this should verify "guix"
> > itself, and thus everything else.
>
> Without the "guix publish" on aneto, it is hard to "guix challenge" on
> balaitou
>
>
> > So I'd reverse your point.  By first challenging Balaitou, we can trust
> > the guix executable and from there we can run 1. and 2.
>
> Yes, if you have root access and network control on balaitou, you can
> expose it ("guix publish").
> Then Alice will "guix challenge" her own store (on aneto) against the
> balaitou one.
>
>
> > Thoughts?
>
> The only issue is that "guix challenge" works with local builds.
> So Alice needs to locally build everything used on balaitou.
> I am imagining that aneto is the Alice's laptop and balaitou a server.
> So, Alice could populate the aneto store using substitutes (from
> ci.guix.gnu.org) for example. And then publishing the result.
> And the server balaitou can build what Alice wants to use on balaitou.
>
>
> Well, all this is on theory and principles. :-)
>
> Hope that helps.
>
> Cheers,
> simon
>
>