Re: [PATCH v3 04/35] upload-pack: convert to a builtin

From: Jeff King <peff@peff.net>
Date: Feb 22, 2018, 23:23 UTC
Message-ID: <20180222232326.GA8585@sigill.intra.peff.net>
In-Reply-To: <20180222230515.GA976@sigill.intra.peff.net>

On Thu, Feb 22, 2018 at 06:05:15PM -0500, Jeff King wrote:

Show 16 quoted lines

> On Thu, Feb 22, 2018 at 02:42:35PM -0800, Jonathan Nieder wrote:
> 
> > > I couldn't quite get it to work, but I think it's because I'm doing
> > > something wrong with the submodules. But I also think this attack would
> > > _have_ to be done over ssh, because on a local system the submodule
> > > clone would a hard-link rather than a real fetch.
> > 
> > What happens if the submodule URL starts with file://?
> 
> Ah, that would do it. Or I guess any follow-up fetch.
> 
> I'm still having trouble convincing submodules to fetch _just_ the
> desired sha1, though. It always just fetches everything. I know there's
> a way that this kicks in (that's why we have things like
> allowReachableSHA1InWant), but I'm not sufficiently well-versed in
> submodules to know how to trigger it.

<facepalm> This won't work anyway. I was right when I said that we don't redirect stderr for rev-list, but of course it's stdout that determines the pager behavior. So I don't think you could get rev-list to trigger a pager here.

I don't think there's currently any vulnerability, but it's more to do with luck than any amount of carefulness on our part.

-Peff