Crypto Domain Manager

Automate all your cryptographic needs!

Goals

• Zero downtime
• Automatic certificate renewal
• Spam protection
• Updated DNS records

Configure once and always stay up to date.

Use cases

• Renew letsencrypt certicates
• Derive all kinds of data from the signature
• Ensure everything is secure

External Service APIs

• Domain Certificate: letsencrypt.org
• DNS Record Updates: inwx.de

Linux Services

• DKIM signatures:
  • rspamd
• Reload systemd services:
  • apache2
  • postfix
  • dovecot
  • rspamd
  • traefik in Docker

Managed DNS Records

• TLSA - for DNS based authentication of named entities DANE
• DKIM - domain keys for email signatures and spam detection
• CAA - specify the CA
• DMARC, SPF, ADSP - configure secure DNS

No downtime strategy

Updating keys, certifcates and other needs 3 steps to prevent gaps in availabillity:

1. Prepare: Create certificates, keys etc. and publish corresponding records to DNS.
2. Rollover: Apply new certificates and keys, because now negative cache TTL on DNS is reached.
3. Cleanup: Delete all no more needed stuff from disk and DNS.

Needed Plugins and Dependencies

• dnsuptools: to interface with DNS API -- updating DNS entries
• dehydrated: to get new certificate (included with cryptdomainmgr)
• rspamd: to create (and use) DKIM keys

Installation

These libraries are needed for pycurl used by dnsuptools for automatic ip retrieving:

apt install -y libcurl4-openssl-dev libssl-dev

This comman is used by dehydrated to communicate with letsencrypt for certificate renewal:

apt install -y curl

For DKIM we need rspamd:

apt install -y lsb-release wget # optional
CODENAME=`lsb_release -c -s`
wget -O- https://rspamd.com/apt-stable/gpg.key | apt-key add -
echo "deb [arch=amd64] http://rspamd.com/apt-stable/ $CODENAME main" > /etc/apt/sources.list.d/rspamd.list
echo "deb-src [arch=amd64] http://rspamd.com/apt-stable/ $CODENAME main" >> /etc/apt/sources.list.d/rspamd.list
apt update
apt install -y rspamd

Now install the cryptdomainmgr. This pulls all need dependencies.

python2 -m pip install cryptdomainmgr

Feel free to try python3, but inwx client doesn't support it.

python3 -m pip install cryptdomainmgr

Documentation

We need help here!

For now please look at:

• German project description and tutorial: https://www.entroserv.de/offene-software/cryptdomainmgr
• Slides: https://github.com/TheTesla/cryptdomainmgr-talk
• Look at the configfiles examples

hints:

• Multiple Configfiles with priority allowed
• Specify content of config file content as argument

Next goals

• improve documentation
• docker support
• website
• automated tests
• nsupdate for DNS updates

Long term goals:

• ARC key renewal
• WPIA integration
• DNSSEC key renewal
• TXT record (may collide with SPF and other TXT based records)
• multi server support for one domain: TLSA delete by timeout
• constrain minimum renewal/phase time interval
• validations - ensure signatures are used correctly
• run as service
• PowerDNS support

Contributions

If you like the project feel free to give me a star. Please let us know if you use this project.

All kind of contributions are welcome.