The pain of HTTPS

time to read 4 min | 652 words

imageA few weeks ago we started looking into what it would take to run RavenDB 4.0 over HTTPS.

Oh, not the actual mechanics of that, we had that covered a long time ago, and pretty much everything worked as expected. No, the problem that we set out to solve was whatever we could get RavenDB to Just Work over HTTPS without requiring the admin to jump through hops. Basically, what I really wanted was a way to just spin up the server and have it running on HTTPS by default.

That turned out to be a lot harder then I wished it would be.

HTTPS has two very distinct goals:

  • To encrypt communication between two parties.
  • To ensure that the site you visited is actually the site you thought you visited.

The first portion can be handled by generating the certificate yourself, and the communication between client & server would be encrypted. So far so good, but the second portion is probably more important. If my communication with is encrypted, that doesn’t really help me all that much, I’m afraid.

Verifying who you are is a very important component of HTTPS, and that is something that we can’t just ignore. Well, technically speaking I guess that RavenDB could have installed a root CA into the system during installation, but the mere thought of doing that is giving me a pause, so I really don’t want to try and do that.

And without doing that, we can’t really support HTTPS. Remember that things like Let’s Encrypt won’t work here. RavenDB is often deployed on closed networks, and without having a publicly visible domain to run. My RavenDB is running on oren-pc.hrhinos.local, for example, and I think you’ll find that it is a bit hard to get a Let’s Encrypt certificate for this.

So we can’t just magically get a certificate and have it work.

While I wish there was a way to just have encryption over the wire, without validation of identity, that would be pretty pointless with such things as man in the middle attacks.

So what do we do in RavenDB 4.0 with regards to HTTPS?

We rely on the admin (shocking, I know). They can either generate a self signed certificate and trust it ( a matter of a few shell commands on any platform ) or use their organization’s certificate (either trusted internally or externally obtained). RavenDB doesn’t care about that, but if you provide a certificate, it will ensure that all communication are SSL encrypted.

The client API exposes a method that let you control certificate validation, which make it easier if you need to customize the authentication policy. On the server side, however, we take things differently. Instead of letting the user configure trust policies in certificates, we decided to ignore the issue completely. Or, to be rather more exact, to specify that RavenDB is going to lean on the operating system for such decisions. A simple scenario is an administrator that define a cluster of servers and generate a self signed certificate(s) for them to use. The administrator need to make sure that the certificate(s) in question are trusted by all nodes in the cluster. RavenDB will refuse to connect over HTTPS to an untrusted source.

Yes, I’m aware of all the horrible things that this can do (certificate expiration kills the system, for example), but we couldn’t think of any way were not doing this wouldn’t result in even worse situations.

RavenDB has support for encrypted databases, but we don’t allow them to be accessed from non secured connection, or to connect to non secure destinations. So the data is encrypted at rest and over the wire, and the admin is responsible to making sure that the certs are up to date and valid (or at least trusted by the machines in question).