Public SourceMage Discussion List

["Jeremy Blosser (emrys)" <jblosser-smgl AT firinn.org>]

On Aug 29, Sergey A. Lipnevich [sergey AT optimaltec.com] wrote:
> Quoting "Jeremy Blosser (emrys)" <jblosser-smgl AT firinn.org>:
> 
> > On Aug 29, Sergey A. Lipnevich [sergey AT optimaltec.com] wrote:
> >> Quoting Seth Alan Woolley <seth AT positivism.org>:
> >>
> >> > DRAFT, although this is one case where we're actually moving on it
> >> > quickly, so it's more of a last call for objections.
> >> >
> >>
> >> So here goes: I object.
> >>
> >> 1. Hash collision is not a problem when it comes to source tarballs,
> >> so please don't use it as a reason to switch to signatures. We
> >> could've as easily hashed them with CRC32 or with 10K-bit hash.
> >> *Either* way provides *no* security.
> >
> > If someone is able to modify the sources while keeping the hash intact, we
> > can't detect it just checking the hash.  This is a problem.  If we're 
> > using
> 
> I would agree with you if there were an example of that. Examples of
> generating a collision in the hash don't count because they do not
> produce a valid source.  Or, I should say, do not produce valid source
> yet. Chances of this happening are much lower than producing a hash
> collision.

It's probably only a matter of time at this point til it happens
publically, and keep in mind that history indicates that whatever the
private sector is doing today was done by the NSA 10 years ago.
Regardless, the sorcery team's position as I understand is that they want
to switch sooner than later so they don't have to be hash experts.  Their
talents are better used elsewhere.

...
> > signature check is the same as what you downloaded.  I don't think we can
> > say this any clearer than we have, so the fact it keeps coming up means to
> > me that people just don't want to hear it.  There's simply no reason a
> > signature has to mean more than we tell our users it means.  It's not even
> 
> Yes there is. Signing a document means you *read* it and *agree* with it. 
> Why
> signing a tarball shouldn't mean the same.
...
> > Again, there's no reason it has to mean this.  If you sign for a package
> > delivered to your neighbor, does it bind you to any claims that the 
> > package
> > isn't a mail bomb?  Signatures are used for all kinds of things in the 
> > real
> > world and digital world.  What it means is what we say it means.
> 
> You're signing the receipt, meaning you agree that you received the
> package.  There's no analog that I can think of in terms of source code
> tarballs.  Package has been accepted by the carrier, inspected for
> controlled objects, and was wrapped. Package has a return address that
> has likely been verified, and a trail of how it got to you. There's no
> wrap or return address on tarballs, and nobody inspects them.  However,
> see above about the analogy of signatures on documents. I think it suits
> better.

I wasn't trying to make a 1-to-1 analogy, I was only noting that signatures
are used for different things, even in the real world.  A signature for a
package means the person signing received the package.  A signature on an
itemized invoice means that the person signing inspected the contents and
verified what was there.  People can understand the difference, and this is
not dissimilar to what we're talking about doing with GPG signing, even if
it's not the exact same thing.

Even GPG signing an email does not mean that I completely agree with the
contents, or always will.  If you pull out this signed mail in 10 years it
will not mean that you can make me say I agree with what it says (I may
have changed my mind), but you can make me say I did write it on this date.

> In short, I object to *mandatory* GPG signatures, and I refuse to sign 
> source
> that's not mine with my name.

Would you be willing to sign using a key that did not have your name, but
had a UID:

"Sourcemage download verification key <downloadverification AT sourcemage.org>" ?

instead?

For the record, I originally felt as you did.  I changed my mind for two
reasons (and one of them alone would have not done it):

1) I understand the sorcery team's position of wanting to offload this, and
I agree with it.

2) I believe that we can explicitly tell users what our signatures mean and
don't mean.  Stuffing it in the key UID is one form of this.

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