SafeDNS Authenticator plugin for Certbot

ans-group/certbot-dns-safedns - Docker image

About

This container uses the SafeDNS Authenticator plugin for Certbot. It utilizes API calls to create and remove DNS TXT records for domain ownership validation.

How to use this image

1, Create the /etc/letsencrypt to house your configuration and your certificates

mkdir -p /etc/letsencrypt

2, Create the /etc/letsencrypt/safedns.ini configuration file with the below content

dns_safedns_auth_token = <YOUR API KEY HERE>
dns_safedns_propagation_seconds = 60

3, Set permissions for the newly created configuration file

chmod 0600 /etc/letsencrypt/safedns.ini

4, Test run the container

docker run -it \
  -v /etc/letsencrypt:/etc/letsencrypt \
  ans-group/certbot-dns-safedns:latest \
    certonly \
      -d yourdomain.com \
      --agree-tos \
      --no-eff-email \
      --email [email protected] \
      --test-cert

Usage examples

Verify current certificates

docker run -it \
  -v /etc/letsencrypt:/etc/letsencrypt \
  ans-group/certbot-dns-safedns:latest \
    certificates

Delete a certificate

docker run -it \
  -v /etc/letsencrypt:/etc/letsencrypt \
  ans-group/certbot-dns-safedns:latest \
    delete --cert-name yourdomain.com

Renew all certificates

docker run -it \
  -v /etc/letsencrypt:/etc/letsencrypt \
  ans-group/certbot-dns-safedns:latest \
    renew

The certbot-dns-safedns Plugin

Setup

apt install certbot python3-pip
pip3 install --upgrade certbot-dns-safedns

Execution

certbot certonly --authenticator dns_safedns

Warning: Certbot might tell you that it doesn't have permissions to write to its log file. However, if you run certbot as sudo, you won't have access to the SafeDNS plugin if you didn't install the plugin as sudo.

This will result in the following error from Certbot:

Could not choose appropriate plugin: The requested dns_safedns plugin does not appear to be installed

To get around this just do:

sudo pip3 install --upgrade certbot-dns-safedns
sudo certbot certonly --authenticator dns_safedns

If you get any Python cryptography errors, such as:

ContextualVersionConflict: ...

Just make sure to upgrade your pyopenssl.

sudo pip install --upgrade pyopenssl

Credentials and Config Options

Use of this plugin can be simplified by using a configuration file containing SafeDNS API credentials, obtained from your ANS Portal account page. See also the SafeDNS API documentation.

An example safedns.ini file:

dns_safedns_auth_token = 0123456789abcdef0123456789abcdef01234567
dns_safedns_propagation_seconds = 20

The path to this file can be provided interactively or using the --dns_safedns-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 password to your ANS Portal 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_safedns \
  --dns_safedns-credentials ~/.secrets/certbot/safedns.ini \
  --dns_safedns-propagation-seconds 900 \
  -d 'example.com' \
  -d '*.example.com'

Build

The package for the SafeDNS plugin is hosted on PyPI here: https://pypi.org/project/certbot-dns-safedns/

To build and upload the package from source, first ensure you've increased the version number in setup.py.

Delete the build, dist and .egg-info directories if they are present from a previous build.

Then run:

python3 setup.py sdist bdist_wheel

Deployment

python3 -m twine upload dist/*

Warning: Use the username: __token__, along with the token registered on PyPI.