Operations grimoire/TLS certificates

TLS certificates should be used for every service we provide, so we can encrypt the communications.

Let's Encrypt

Let's encrypt commands

2016-07-31 utility rename. Client upgraded on Ysul. New client name is certbot, not anymore letsencrypt.

acme-v02 migration. If you've a complaint acme-v01.api. isn't available, add --server https://acme-v02.api.letsencrypt.org/directory.

Generate a certificate

Devserver role, for example Ysul or WindRiver (/var/letsencrypt-auto folder) :

certbot certonly -a webroot --webroot-path=/var/letsencrypt-auto -d foo.nasqueron.org

Dwellers (container will use /www):

certbot certonly --server https://acme-v02.api.letsencrypt.org/directory -a webroot --webroot-path=/www -d bar.nasqueron.org

Generate a certificate for several sites

-d foo.nasqueron.org -d bar.nasqueron.org

If a certificate for foo already existed, it will offer to extend it to a new alternative name, which is probably a good idea.

Generate a certificate through DNS

DNS can be used to generate certificates for domains. For example, the Openfire XMPP certificate is generated like this:

   certbot certonly --server https://acme-v02.api.letsencrypt.org/directory --manual --manual-auth-hook /etc/letsencrypt/acme-dns-auth --preferred-challenges dns --debug-challenges -d xmpp.nasqueron.org -d nasqueron.org -d conference.nasqueron.org

From December 2023, you can use this command on FreeBSD servers where T1505 Let's Encrypt standard installation have been deployed:

   certbot certonly --manual --manual-auth-hook /usr/local/etc/letsencrypt/acme-dns-auth --preferred-challenges dns --debug-challenges -d subdomain.nasqueron.org

This uses a specialized DNS server deployed on our Docker PaaS to serve dynamic TLS records under .acme.nasqueron.org, rOPS: roles/paas-docker/containers/acme_dns.sls.

Support files were previously only deployed to paas-docker role through rOPS: roles/paas-docker/letsencrypt/files.

Renew all certificates

certbot renew

Installation on nginx

Allow Let's encrypt validation

   include includes/letsencrypt;

This will use rOPS: roles/webserver-core/nginx/files/includes/letsencrypt nginx configuration.

Serve TLS certificate

   include includes/tls;
   ssl_certificate /srv/letsencrypt/etc/live/xmpp.nasqueron.org/fullchain.pem;
   ssl_certificate_key /srv/letsencrypt/etc/live/xmpp.nasqueron.org/privkey.pem;

This will configure a compromise between security and compatibility, based on Intermediate Mozilla SSL config. The current configuration is served by rOPS: roles/webserver-core/nginx/files/includes/tls.

If you prefer to restrict the resource for TLS 1.3, and accepts to block legacy clients, you can also use with D3251:

   include includes/tls-modern-only;
   ssl_certificate /srv/letsencrypt/etc/live/xmpp.nasqueron.org/fullchain.pem;
   ssl_certificate_key /srv/letsencrypt/etc/live/xmpp.nasqueron.org/privkey.pem;

Special considerations

New server

Let's encrypt client is available on Ysul (natively) and Dwellers (as a wrapper script for a Docker container).

Fill a task in Servers component, subscribe Sandlayth and Dereckson to deploy it on a new server.

A salt state would be nice for such purpose. There is work-in-progress on that matter through D3248.

Internationalized domain names

Punycode conversion

Both for web server configuration and certificate authority, name must be converted to Punycode (RFC 3492): https://www.punycoder.com/

Let's encrypt support

Let's encrypt has supported IDN since 2016. We use it for dægrefn.nasqueron.org certificate.

Previously, they were afraid: attackers could register a domain with a Cyrillic character matching a real domains. As some people consider it's the responsibility of the CA to mitigate such risks, the feature has been several times postponed.

StartSSL

StartSSL is not in activity anymore. It was used at Nasqueron when Let's Encrypt didn't support IDN.