Re: [PATCH 2/2] submodule: munge paths to submodule git directories

> > I think this backwards-compatibility is necessary to avoid pain. But
> > until it goes away, I don't think this is helping the vulnerability from
> > 0383bbb901. Because there the issue was that the submodule name pointed
> > back into the working tree, so this access() would find the untrusted
> > working tree code and say "ah, an old-fashioned name!".
> [...]
> 
> Oh I know that this doesn't help with that vulnerability.  As you've
> said we fix it and now disallow ".." at the submodule-config level so
> really this path is simply about using what we get out of
> submodule-config in a more sane manor.

> > One interesting thing about url-encoding is that it's not one-to-one.
> > This case could also be %2F, which is a different file (on a
> > case-sensitive filesystem). I think "%20" and "+" are similarly
> > interchangeable.
> > 
> > If we were decoding the filenames, that's fine. The round-trip is
> > lossless.
> > 
> > But that's not quite how the new code behaves. We encode the input and
> > then check to see if it matches an encoding we previously performed. So
> > if our urlencode routines ever change, this will subtly break.
> > 
> > I don't know how much it's worth caring about. We're not that likely to
> > change the routines ourself (though certainly a third-party
> > implementation would need to know our exact url-encoding decisions).
> 
> This is exactly the reason why I wanted to get some opinions on what the
> best thing to do here would be.  I _think_ the best thing would probably
> be to write a specific routine to do the conversion, and it wouldn't
> even have to be all that complex.  Basically I'm just interested in
> converting '/' characters so that things no longer behave like
> nested directories.