The option is supposed to be used as a fallback for certificates
validation. For instance, the option will be used if 's2s_cafile'
option is not set. The value should be a path to a file containing
CA certificate(s) in PEM format, e.g.:
ca_file: "/etc/ssl/certs/ca-bundle.pem"
The option is supposed to replace existing options 'c2s_certfile',
's2s_certfile' and 'domain_certfile'. The option accepts a list
of file paths (optionally with wildcards "*") containing either
PEM certificates or PEM private keys. At startup, ejabberd sorts
the certificates, finds matching private keys and rebuilds full
certificates chains which can be used by fast_tls. Example:
certfiles:
- "/etc/letsencrypt/live/example.org/*.pem"
- "/etc/letsencrypt/live/example.com/*.pem"
The major goal is to simplify certificate management in ejabberd.
Currently it requires some effort from a user to configure certficates,
especially in the situation where a lot of virtual domains are hosted.
The task is splitted in several sub-tasks:
* Implement basic certificate validator. The validator should check all
configured certificates for existence, validity, duration and so on. The
validator should not perform any actions in the case of errors except
logging an error message. This is actually implemented by this commit.
* All certificates should be configured inside a single section (something
like 'certfiles') where ejabberd should parse them, check the full-chain,
find the corresponding private keys and, if needed, resort chains and
split the certficates into separate files for easy to use by fast_tls.
* Options like 'domain_certfile', 'c2s_certfile' or 's2s_certfile' should
probably be deprecated, since the process of matching certificates with the
corresponding virtual hosts should be done automatically and these options
only introduce configuration errors without any meaningful purpose.
