Securing Ubooquity with Let’s Encrypt on Synology DSM

Update, 2020-06-11: I’m now using Synology’s built-in NGINX-based reverse proxy instead. The instructions below may not work.

Whew, that’s a very specific title. I don’t know if this will be useful to anyone else, but it took a fair amount of work to figure it out, so I figured I’d document it. There will be more Mac stuff soon, I promise!

If you haven’t heard, Let’s Encrypt is an excellent service, with the aim of securing the internet by offering free HTTPS certificates to anyone who requests one. In fact, I’m using one on this website right now. 🙂

With DSM 6.0, Synology added the ability to request a free certificate from Let’s Encrypt to secure your NAS. DSM handles renewing your certificate, which must happen every 90 days (one of the limitations of the free certificate, but nothing that can’t be automated).

Unrelated for the moment, but I’ve been using Ubooquity (through Docker!) for the past few months, and it’s been pretty neat. You can point Ubooquity to a directory of ePub and PDF files, and it’ll allow you to access the files remotely using reader apps like Marvin, KyBook, or Chunky. I have a habit of buying tech books and comics through Humble Bundle sales, but transferring the files to my iPad through iTunes/iBooks is clunky and requires a fair amount of disk space upfront.

Although Ubooquity supports user authentication, you’ll want that to happen over HTTPS, to keep your passwords secure. Luckily, Ubooquity supports HTTPS, but requires the certificate (and other associated files) to be in a format called a “keystore”. What?!

Here’s how to leverage DSM’s Let’s Encrypt support to secure Ubooquity, automatically.

1. First, you’ll want to set up Let’s Encrypt in DSM’s Control Panel. See Synology’s documentation.
2. Next, you’ll want to get Ubooquity up and running (I recommend the Docker image mentioned above). Synology’s documentation covers that, too. If your eBook library is a mess Calibre will make quick work of that.
3. For this to work, you’ll also need the Java 8 JDK installed. This will give you access to the ‘keytool’ command you’ll need to create your keystore. Once again, see Synology’s documentation.
4. Now, you’ll put all of this together. In a nutshell: you’re going to use the Let’s Encrypt certs that DSM has helpfully obtained for you, convert those to a keystore, put the keystore in Ubooquity’s config directory, and tell Ubooquity to use it to secure its interface. Here’s a script to get you started – note that you’ll need to edit lines 11, 12, and 15 for your environment. Thanks to Saltypoison on the Ubooquity forums for most of the code that became this script!
5. Once you’ve successfully run the script, I recommend using DSM’s Task Scheduler to have it run once a day. This way, Ubooquity’s certificate will always be up to date with DSM’s certificate. That’s right, I’m going to link you to Synology’s documentation.
6. Finally, you’ll need to tell Ubooquity where to find your keystore. Login to the Ubooquity admin interface, then click the Security tab. You’ll see two boxes – one for the path to your keystore, and one for the keystore password. Enter both. Click ‘Save and Restart’ at the top-right corner.
7. Now, try accessing your Ubooquity instance using https and your FQDN! If it doesn’t work, make sure you’re forwarding the appropriate ports from your router to your Synology server – you’ll need to do this for both the eBook interface, and the admin interface (which are accessible via two different ports).

I’ll probably post more Synology/Docker stuff in the future, as I’ve been spending a lot of time with both. They’re really awesome!