Re: git + ssh + key authentication feature-request

Junio C Hamano [off-list ref] wrote:

So while you could make a repository "/pub/project.git" the home
directory of _one_ UNIX user, and store her key in the file
"/pub/project.git/.ssh/authorized_keys", that would not work
very well for a shared repository setup if you want to be able
to tell more than one physical users apart.

Ahh!  But you can.  The trick is to set the remote user's identity based
on the key he uses to authenticate himself.  This doesn't work if you
use password authentication.  You add items of the form
`environment="VAR=VALUE"' to the end of each authorized_keys entry, as
appropriate for whoever it is that owns the corresponding private key;
the GIT_{AUTHOR,COMMITTER}_{NAME,EMAIL} variables are ideal choices to
set here.  You could set some other variables and do some more
sophisticated checking of who's doing what, which would require souping
up git-daemon somewhat, but I don't think it's beyond the realms of
possibility.

It's important that your users can't use this SSH access to mess with
the shared user's SSH configuration itself, but, hey, that sort of
restricted access is what git-daemon is for, right?

You _could_ tell them to use the same -l option and log-in as the same
UNIX user with their own keys, though.  But that way you cannot tell
which developer pushed into the repository (of course if you trust the
commits, commit log message would say the committer ident).

I think the problem there is more that the commits themselves were
created elsewhere, where this server wasn't watching, and therefore it
pretty much has to take the committer and author information there on
trust.

-- [mdw]