NetAuth is a network identity and authentication provider. It allows you to have one user account that is available to a lot of different machines.

What Does it Do?

If you’re familiar with LDAP and Kerberos, you can skip down to the next section, NetAuth is an implementation of the services that LDAP and Kerberos can provide for a network, but with a much smaller scope and certain assumptions.

NetAuth provides two key components: a limited directory of user information, and a secrets store. The directory provides the most critical information about an entitiy such as the ID, numeric ID, name, etc. What NetAuth does NOT provide is a general purpose directory. That is something which is not really in scope for a small authentication service and is implemented exceptionally well by the LDAP standard. If you want such a server you should really setup LDAP, which you could either use for authentication (something it was not designed for) or use it as a directory that just contains information. If you need to authenticate your access to LDAP it would not be too difficult to back up LDAP into NetAuth, but this functionality is left as an exercise to the reader.

For identity NetAuth provides a fairly standard password verification system that is not unlike that used by a website login system. The user’s password is sent via a secure channel to the NetAuth server where it is validated against a hashed copy. If the password checks out, then NetAuth will return a success message to the calling client. In failure cases NetAuth will return a message to the client explaining the failure.

Why is this written in Go?

I like Go and it works well with protobuf without needing the host operating system to have good support on its own. Its not the most ideal language for interfacing with PAM or nsswitch, but for writing servers that work with gRPC its quite nice.

Why does this communicate using gRPC and not my favorite protocol?

I like the RPC paradigm, it works well for what I am trying to achieve here and can work without any real thought about the transport. gRPC specifically is capable of working in an environment where the only outbound connection allowed is HTTP, which is a core design goal of this project. While it is a binary protocol, the protobuf definition is public and this will let you do all the normal things such as debugging with wireshark (assuming you have the appropriate security settings in place to observe HTTPS traffic).

How do I hook up other things to NetAuth?

There are several systems available to plug in to NetAuth. For Linux hosts you can use pam-helper and localizer. If you want to pull ssh keys, then you probably want NetKeys.

Other modules are in development, if you want to help out, reach out in #netauth-dev on freenode.

Do you recommend using NetAuth for super important things?

Like all software that runs in a security critical context, it is important to determine what your allowable risks are. NetAuth is developed by a very small team and has not undergone a formal audit. That being said, it is an extremely well documented codebase, and has very high test coverage.

NetAuth is also designed to be very hard to misconfigure. It is much easier to configure an LDAP server in such a way that it will leak passwords than to leak passwords from a NetAuth server.

Why wouldn’t you use LDAP and Kerberos? Why did you build this?

I managed a network that used LDAP and Kerberos for a number of years. These are some incredible technologies and I quite enjoyed the feature sets they provide. The problem though is that LDAP is a slimmed down version of a protocol so complex it could never be implemented (the DAP), and Kerberos is a protocol that makes certain assumptions about the state of the network and the services that are available. Both LDAP and Kerberos require tooling to interact with and as far and wide as I have searched, I have found no good tooling that allows one to interact with the two as a single identity management platform (likely because they aren’t).

While I am a die-hard FOSS supporter and contributor, Microsoft’s Active Directory is by my book the gold standard of tooling for managing an authentication and identity provider. It is intuitive, all-in-one and most importantly, it makes the underlying LDAP and Kerberos servers behave as a single virtual service. I thought long and hard about whether or not I wanted to just build a frontend to LDAP and Kerberos to handle the managerial tasks, but I came to the conclusion that if I was going to write software from the ground up, I would like to just rebuild the entire stack as a slimmed down version that would do exactly what I wanted. If nothing else I will gain a strong appreciation for the work done by the developers of Kerberos and LDAP.

If I was still managing networks with thousands of users I would probably still stand up LDAP and Kerberos. If I needed a directory of arbitrary information, LDAP is still my first stop. If I needed to do very novel and interesting crypto to secure the network fabric I would still use Kerberos. For simple authentication on my home network or on the Open Source projects I’m involved in, however, these technologies are overkill.

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