On Fri, 2004-04-02 at 12:29, Erik LaBianca wrote:
> > I'll give this a try too. I think, though, what I want is for the
> > script to automatically make a decision that an SRPM with a valid GPG
> > does not have to have it's md5sum checked.
> >
> > Slightly more paranoid is to make the following checks:
> > 1] GPG signature of SRPM
> > 2] Is the md5sum of the relevant SRPM in the md5sum file?
> > 3] GPG signature of md5sum file
> > 4] Did the same key sign both files?
> >
> > If all pass, then pass the test.
> > If 1] Pass and 2] Is fail, pass the test.
> > All other cases fail.
>
> I don't see the point in this. All it adds is protection against the
> unlikely case that there is a bug in the MD5 checksum code or crypto
> routines included in GPG. These tools are designed and tested to be
> reliable, second guessing them is a waste of time. If you know enough
> about crypto to prove its necessary, I suggest applying that knowledge
> to improving those tools.
>
The pointlessness is why I started off by saying a valid GPG signature
makes checking the MS5sum unnecessary. (ie: only check step 1 above, all
the rest is unnecessary.)
The more paranoid method I describe checks for inconsistencies between
the SRPM and other documentation on the SRPM (same person signed both
files which seem to both refer to the same SRPM. A double check.) In
the real world, if someone could compromise an SRPM on a server, they
could probably also compromise the md5sum file.
This stems from a piece of my original post which you snipped which
states that I was testing fedora-startqa and it verified the SRPM GPG
but then errored out because the MD5sum file wasn't up-to-date (and so
couldn't find the SRPM listed there.) From your comments here, I think
you're planning on removing the md5sum checking so this problem is going
away.
> You still haven't necessarily verified the gpg signature against a web
> of trust, which is FAR more likely to be the source of a problem. I'm
> not really involved with any of these (webs of trust), but when we
> convert the script over to checking RPM sigs using GPG (imminent) we can
> indicate whether or not the signature that passed was a "trusted" one in
> your review accounts gpg keyring.
>
Yes, distributing trust is the real tricky problem of gpg.
-Toshio
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