Any Firefox add-on people out there?

I’ve had really good luck asking random people to do work for me, so I’m going to try it again.

RFC6698 defines the DANE protocol for attaching information to DNSSEC-secured DNS. Notably, you can validate SSL certificates via DNS. This is a game-changer. The key here is the TLSA DNS record.

Web browsers don’t support this yet, but there is the Extended DNSSEC Validator Firefox add-on at, with source at github.

If you have the newest version of the add-on installed, sites like show up as secure. There is no “invalid certificate” warning. That’s because I’ve published a TLSA record for this zone, telling the browser that the certificate with fingerprint such-and-such on this port on this host is trustworthy. (Install the plugin from the github source, not from the xpi on the site.)

The interesting thing about this add-on is that it uses libunbound to perform DNSSEC validation at the client. Your local DNS servers don’t need to support DNSSEC. All you need to hack on this plugin is a desktop.

But the add-on doesn’t support BSD — it’s Linux, MS, and Mac only. The add-on authors don’t have time for BSD support, but gave me a couple hints on how to implement it. The plugin can’t find libunbound on BSD.

That seems like it would be easy to do. I’m capable of building the add-on from source, but I’ve never programmed any add-ons before. The source code looks like it’s easy to hack, but my efforts all segfaulted Firefox. Obviously, I need more expertise.

So, if you know anything about Firefox add-ons, or have ever wanted to hack on them, this is your chance.

DANE and TLSA are the killer applications for DNSSEC. The ability to validate cryptographic certificates via DNS is a game changer. (Cliche, but true.) You can have separate certificates for separate ports on a host. With DANE, there’s no longer any need for a self-signed certificate to be a disadvantage.