certbot-dns-shellrent

Shellrent DNS Authenticator plugin for Certbot

This plugin automates the process of completing a dns-01 challenge by creating, and subsequently removing, TXT records using the Shellrent Remote API.

Configuration of Shellrent

You will need your username and an API token for filling up the .ini configuration file. To generate your token you have to log in to https://manager.shellrent.com, then go to "My Profile" in the upper right corner, on the left click on "API Key" and finally on "Generate API token".

Remember that you need to set up your authorized IP access first, from the "Profile security" menu voice. Every IP that should use certbot with this plugin need to be added to the authorized ip access list. More info: https://guide.shellrent.com/controllo-degli-accessi-tramite-ip/

Installation

pip install certbot-dns-shellrent

Named Arguments

To start using DNS authentication for shellrent, pass the following arguments on certbot's command line:

(Note that the verbose and seemingly redundant certbot-dns-shellrent: prefix is currently imposed by certbot for external plugins.)

Credentials

An example credentials.ini file:

dns_shellrent_username = myremoteuser
dns_shellrent_token = verysecureremoteusertoken
dns_shellrent_endpoint = https://manager.shellrent.com/api2

The path to this file can be provided interactively or using the --dns-shellrent-credentials command-line argument. Certbot records the path to this file for use during renewal, but does not store the file's contents.

CAUTION: You should protect these API credentials as you would the token to your shellrent account. Users who can read this file can use these credentials to issue arbitrary API calls on your behalf. Users who can cause Certbot to run using these credentials can complete a dns-01 challenge to acquire new certificates or revoke existing certificates for associated domains, even if those domains aren't being managed by this server.

Certbot will emit a warning if it detects that the credentials file can be accessed by other users on your system. The warning reads "Unsafe permissions on credentials configuration file", followed by the path to the credentials file. This warning will be emitted each time Certbot uses the credentials file, including for renewal, and cannot be silenced except by addressing the issue (e.g., by using a command like chmod 600 to restrict access to the file).

Examples

To acquire a single certificate for both example.com and *.example.com, waiting 900 seconds for DNS propagation:

certbot certonly \
  --authenticator dns-shellrent \
  --dns-shellrent-credentials /etc/letsencrypt/.secrets/domain.tld.ini \
  --dns-shellrent-propagation-seconds 900 \
  --server https://acme-v02.api.letsencrypt.org/directory \
  --agree-tos \
  --rsa-key-size 4096 \
  -d 'example.com' \
  -d '*.example.com'

Docker

In order to create a docker container with a certbot-dns-shellrent installation, create an empty directory with the following Dockerfile:

FROM certbot/certbot
RUN pip install certbot-dns-shellrent

Proceed to build the image:

docker build -t certbot/dns-shellrent .

Once that's finished, the application can be run as follows:

docker run --rm \
   -v /var/lib/letsencrypt:/var/lib/letsencrypt \
   -v /etc/letsencrypt:/etc/letsencrypt \
   --cap-drop=all \
   certbot/dns-shellrent certonly \
   --authenticator dns-shellrent \
   --dns-shellrent-propagation-seconds 900 \
   --dns-shellrent-credentials \
       /etc/letsencrypt/.secrets/domain.tld.ini \
   --no-self-upgrade \
   --keep-until-expiring --non-interactive --expand \
   --server https://acme-v02.api.letsencrypt.org/directory \
   -d example.com -d '*.example.com'

It is suggested to secure the folder as follows:: chown root:root /etc/letsencrypt/.secrets chmod 600 /etc/letsencrypt/.secrets