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Re: Time to resurrect multi-key signatures in RPM?



On Fri, 2008-08-29 at 12:07 +0200, Nils Philippsen wrote:
> Build "reproducers" would have to use the exact
> same versions for reproduction attempts.

We keep the logs in Koji that tell us what versions and releases of
packages were used to build things.

> Keep in mind that this can lead to false negatives, i.e. if all
> reproducers use the same compromised compiler package that someone
> managed to sneak in -- this could realistically only show attacks on the
> build system itself.

Of course. The aim of this would only be prevention of a compromised
build system and/or compromised Fedora key causing a distro wide
disaster.

Compromised source of an uploaded package and especially trojaned
compilers are entirely different problems and are mostly beyond the
scope of what distributed trust model is about (as presented here).

I was only using David's compiler comment to illustrate that it is a
good thing for a build to be deterministic. David seems to have
developed a pretty good technique for tackling trojaned compilers (which
distributors should be using regularly, IMHO).

> I think that's a bit dangerous as malicious code could be designed in a
> way that it's edited out before checksumming (make it look like you've
> incorporated the kernel version).

I would say that people that are capable of injecting malicious
instructions streams into binaries of disparate CPUs that always read
"2.6.25.14-108.fc9.i686" should be employed immediately ;-)

But seriously, yeah, there is some danger in that. We could also rely on
some kind of elfdiff or something else instead. There are ways.

-- 
Bojan


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