Re: Useless error message?

Andreas Ericsson wrote:

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

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.

Thanks for the comment.
Jonathan