Re: [RFC 0/2] Git-over-TLS (gits://) client side support

From: Avery Pennarun <apenwarr@gmail.com>
Date: Jan 13, 2010, 23:51 UTC
Message-ID: <32541b131001131551m38ff02acpdd08d9f0562ac84d@mail.gmail.com>
In-Reply-To: <20100113230023.GA9171@Knoppix>

On Wed, Jan 13, 2010 at 6:00 PM, Ilari Liusvaara <ilari.liusvaara@elisanet.fi> wrote:

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> On Wed, Jan 13, 2010 at 05:03:45PM -0500, Avery Pennarun wrote:
>> This is still not very illuminating.  How do you know your replacement
>> will not have these same failure modes?
>
> No client-side fallbacks, key auth works pseudonymously. That takes
> care of them pretty well.

Perhaps I'm being dense, but I don't understand what you mean by either of those.

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>> If you solve your main
>> annoyances with ssh, how do you know you won't introduce any new
>> annoying failure modes?
>
> Ensuring that at least some information make back to client (presuably
> enough to figure out the problem).

Unfortunately revealing information like that is a compromise; it helps attackers as well as legitimate users. It's the same reason login prints "invalid username or password" instead of choosing between "invalid username" and "invalid password."

If you reveal more information than ssh, you'll be accused of being less secure. And since the purpose of your protocol is security, this is a problem.

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>> *Why* can't ssh be fixed to solve the  problem?
>
> Client side fallbacks (may be desired or not!), service not being
> able to intervene on wheither to allow client or not in case of
> keypair auth.

I don't understand that answer. Couldn't ssh be patched to do whatever you want? Particularly if it's just better (optional) diagnostics, you'd think someone would accept the patch for that.

>>  Will I have to generate and manage yet another new set of
>> keys to use the new system?
>
> Yes.

Ouch.

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>> (Even if
>> ssh is hard to set up, I've *already set it up*, so any new
>> alternative starts with an immediate negative score.)
>
> Well, if you like SSH more, then use ssh://...

I'm just looking for a justification for why I *shouldn't* like ssh more. Is the only reason the fact that it might be easier to initially configure the key exchange?

Avery