Re: Useless error message?

On 04/22/2010 12:15 PM, Jonathan Nieder wrote:

Andreas Ericsson wrote:

quoted

On 04/22/2010 11:42 AM, Jonathan Nieder wrote:

quoted

quoted

[1] I do suspect that in the case of failing enter_repo() or missing
git-daemon-export-ok, saying “cannot read the specified repo” would be
fine.  Most of the time, there is not much value in disclosing a more
detailed reason, anyway.

That would make it possible for random attackers to determine whether
a specific user exists on the system, which is very bad indeed.

I guess I am missing something.  How would

(*) $ git clone git://git.example.com/~u/foo
     remote: Cannot read the specified repo

tell me whether that user existed on the system?  If the daemon gives
the same message for ENOENT, missing git-daemon-export-ok, EPERM, and
so on so I cannot distinguish the cases, then I just don’t see the
problem.

If the daemon failed for some other reason, like a flaky network, I
would see

     $ git clone git://git.example.com/~u/foo
     fatal: The remote end hung up unexpectedly

So the extra information could still be helpful, without unwanted
information disclosure.  In the case (*) I learn definitively that the
address I specified does not represent a repo I have access to, rather
than this being some random, transient unexplained problem.

So that would be the new error message for everything that fails, then?

One big reason why I'm not bothered with running the git-daemon on a
public server is that it's very simple. If something goes wrong, it
dies without fiddling about.

How would it benefit you if it said "fatal: Something went wrong, but
I didn't crash" instead of just hanging up? If you have the wrong
repo address, you'd still have to check up with whoever gave it to
you to get it right. If it *does* crash, you'd still have to get
hold of the server admin to tell him that it has crashed.

A minor patch to git-fetch, updating the error message with a few
possible reasons would be far better. I don't care about it myself,
but I'm sure such a patch would be a lot easier to get into git.git
than something that adds a lot of complexity to the git daemon.

-- 
Andreas Ericsson                   andreas.ericsson@op5.se
OP5 AB                             www.op5.se
Tel: +46 8-230225                  Fax: +46 8-230231

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