Easy Security Project: standalone ssh-ldap-helper

I’ve been waiting for quite a while for an official way to centrally manage user authentication keys in OpenSSH. If you have a dozen servers, copying authorized_keys files around is a pain. If you have more than that, it’s really really painful. The OpenSSH guys have had good reasons for not wanting to link LDAP libraries straight into OpenSSH. They also gave some general guidance of what they’d want to see in a patch that supported LDAP authentication.

Jan Chadima from Redhat took OpenSSH up on this, wrote a patch as per spec, and submitted it to OpenSSH. And Damien Miller committed it. LDAP support for OpenSSH will be in 6.2…

…sort of.

The patch adds support for getting a user’s authorized_keys file from a helper program. Redhat includes a helper program, ssh-ldap-helper. That program is not in the OpenSSH patch. And, truthfully, there’s no reason it should be in the main OpenSSH distribution. We’ll see helpers for LDAP, for database lookups, for FUSE and HTTP and whatever weird data storage people come up with. I don’t want the OpenSSH guys spending their time writing these helpers.

But the source code for ssh-ldap-helper is in the Red Hat source RPM. As far as I can tell, it’s under a BSD license.

If you’re looking for a way to contribute to the OpenSSH user community, however, digging into the RPM (it’s just a tarfile), extracting the included OpenSSH code, and adding the patch for ssh-ldap-helper, ssh-ldap-wrapper, and the man page is pretty easy. I got that far, after all! I imagine that someone with a little bit of knowledge could make it compile on xBSD. Or at least, it’s a place to start.

You’d make my life a lot easier. And give me more time to finish the new edition of Absolute OpenBSD. That’s what you lot want me to do with my time, isn’t it? (I’ll have a post on that status in a few days.)

I also have to give props to Red Hat on this. They had a need in OpenSSH. They were given the requirements for that need to be met in mainline OpenSSH. And they met those needs and submitted the patch. Everyone cooperated, everyone gets what they need. That is how open source should work. Given how some other open source companies and projects are behaving lately, this makes me feel pretty good about the BSD community.

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