Re: Server side programs

From: Junio C Hamano <junkio@cox.net>
Date: Oct 23, 2005, 00:30 UTC
Message-ID: <7vll0l6pn7.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <435ABB99.5020908@op5.se>

Andreas Ericsson <ae@op5.se> writes:

> Are git-receive-pack and git-upload-pack the only two binaries that get 
> called directly over a SSH-tunnel?

There are git-ssh-fetch and git-ssh-upload which call each other (and the older name pairs git-ssh-push and git-sh-pull do so as well). However, you do not have to use these commit walkers over ssh; fetch-pack/upload-pack pair work quite well.

I think your question is "what is the absolute minimum set of binaries you need to allow", so I think the two listed are enough. If you want to let your users coming over SSH *create* a new repository on your machine, you would need a bit more, though (namely, shell access to run mkdir and git-init-db).

> The reason I'm asking is that I'm adding support for userrelative paths 
> (git pull ssh://host:~user/somedir) and removing the possibilities to 
> use a compromised but limited account for finding out what other 
> useraccounts are available.

Sorry, it is not clear to me what you are adding. I do this regularly:

	$ git push kernel.org:git/
	$ git fetch kernel.org:git/

to push into and fetch from $HOME/git/ repository on the other end.

Also I can do this already (assuming the other end hangs all users under the same directory, presumably /home/$user):

	$ git fetch kernel.org:../torvalds/git/

Are you in addition trying to let me do this:

	$ git fetch kernel.org:~torvalds/git/

which would work even when ~torvalds == /home/torvalds and ~junio == /home2/junio, without having to tell people where the user home directories are?

At one point, Linus posted an outline of "restricted login shell for use with git over ssh". I think you could start from there, perhaps extend it so that it checks the binaries *and* pathnames the user can specify (e.g. only under your own $HOME is allowed, and no /../ in them, or something silly like that).