docker-mailserver/target/bin/open-dkim

#!/bin/bash

# shellcheck source=../scripts/helpers/index.sh
source /usr/local/bin/helpers/index.sh

if [[ -f /etc/dms-settings ]] && [[ $(_get_dms_env_value 'ENABLE_RSPAMD') -eq 1 ]]; then
  if [[ $(_get_dms_env_value 'ENABLE_OPENDKIM') -eq 1 ]]; then
    log 'error' "You enabled Rspamd and OpenDKIM - OpenDKIM will be implicitly used for DKIM keys"
  else
    /usr/local/bin/rspamd-dkim "${@}"
    exit
  fi
fi

KEYSIZE=2048
SELECTOR=mail
DOMAINS=

function __usage() {
  printf '%s' "${PURPLE}OPEN-DKIM${RED}(${YELLOW}8${RED})

${ORANGE}NAME${RESET}
    open-dkim - Configure DKIM (DomainKeys Identified Mail)

${ORANGE}SYNOPSIS${RESET}
    setup config dkim [ OPTIONS${RED}...${RESET} ]

${ORANGE}DESCRIPTION${RESET}
    Creates DKIM keys and configures them within DMS for OpenDKIM.
    OPTIONS can be used when your requirements are not met by the defaults.
    When not using 'ACCOUNT_PROVISIONER=FILE' (default), you may need to explicitly
    use the 'domain' option to generate DKIM keys for your mail account domains.

${ORANGE}OPTIONS${RESET}
    ${BLUE}Generic Program Information${RESET}
        help      Print the usage information.

    ${BLUE}Configuration adjustments${RESET}
        keysize   Set the size of the keys to be generated.
                  Possible values: 1024, 2048 and 4096
                  Default: 2048
        selector  Set a manual selector for the key.
                  Default: mail
        domain    Provide the domain(s) for which to generate keys for.
                  Default:  The FQDN assigned to DMS, excluding any subdomain.
                            'ACCOUNT_PROVISIONER=FILE' also sources domains from mail accounts.

${ORANGE}EXAMPLES${RESET}
    ${LWHITE}setup config dkim keysize 4096${RESET}
        Creates keys with their length increased to a size of 4096-bit.

    ${LWHITE}setup config dkim keysize 1024 selector 2023-dkim${RESET}
        Creates 1024-bit sized keys, and changes the DKIM selector to '2023-dkim'.

    ${LWHITE}setup config dkim domain 'example.com,another-example.com'${RESET}
        Only generates DKIM keys for the specified domains: 'example.com' and 'another-example.com'.

${ORANGE}EXIT STATUS${RESET}
    Exit status is 0 if command was successful. If wrong arguments are provided or arguments contain
    errors, the script will exit early with exit status 2.

"
}

_require_n_parameters_or_print_usage 0 "${@}"

while [[ ${#} -gt 0 ]]; do
  case "${1}" in
    ( 'keysize' )
      if [[ -n ${2+set} ]]; then
        KEYSIZE="${2}"
        shift
        shift
      else
        _exit_with_error "No keysize provided after 'keysize' argument"
      fi
      ;;

    ( 'selector' )
      if [[ -n ${2+set} ]]; then
        # shellcheck disable=SC2034
        SELECTOR="${2}"
        shift
        shift
      else
        _exit_with_error "No selector provided after 'selector' argument"
      fi
      ;;

    ( 'domain' )
      if [[ -n ${2+set} ]]; then
        DOMAINS="${2}"
        shift
        shift
      else
        _exit_with_error "No domain(s) provided after 'domain' argument"
      fi
      ;;

    ( * )
      __usage
      _exit_with_error "Unknown options '${1}' ${2:+and \'${2}\'}"
      ;;

  esac
done

DATABASE_VHOST='/tmp/vhost.dkim'
# Prepare a file with one domain per line:
function _generate_domains_config() {
  local TMP_VHOST='/tmp/vhost.dkim.tmp'

  # Generate the default vhost (equivalent to /etc/postfix/vhost),
  # unless CLI arg DOMAINS provided an alternative list to use instead:
  if [[ -z ${DOMAINS} ]]; then
    _obtain_hostname_and_domainname
    # uses TMP_VHOST:
    _vhost_collect_postfix_domains
  else
    tr ',' '\n' <<< "${DOMAINS}" >"${TMP_VHOST}"
  fi

  # uses DATABASE_VHOST + TMP_VHOST:
  _create_vhost
}

_generate_domains_config
if [[ ! -s ${DATABASE_VHOST} ]]; then
  _log 'warn' 'No entries found, no keys to make'
  exit 0
fi

while read -r DKIM_DOMAIN; do
  mkdir -p "/tmp/docker-mailserver/opendkim/keys/${DKIM_DOMAIN}"

  if [[ ! -f "/tmp/docker-mailserver/opendkim/keys/${DKIM_DOMAIN}/${SELECTOR}.private" ]]; then
    _log 'info' "Creating DKIM private key '/tmp/docker-mailserver/opendkim/keys/${DKIM_DOMAIN}/${SELECTOR}.private'"

    opendkim-genkey \
      --bits="${KEYSIZE}" \
      --subdomains \
      --domain="${DKIM_DOMAIN}" \
      --selector="${SELECTOR}" \
      --directory="/tmp/docker-mailserver/opendkim/keys/${DKIM_DOMAIN}"
  fi

  # fix permissions to use the same user:group as /tmp/docker-mailserver/opendkim/keys
  chown -R "$(stat -c '%U:%G' /tmp/docker-mailserver/opendkim/keys)" "/tmp/docker-mailserver/opendkim/keys/${DKIM_DOMAIN}"

  # write to KeyTable if necessary
  KEYTABLEENTRY="${SELECTOR}._domainkey.${DKIM_DOMAIN} ${DKIM_DOMAIN}:${SELECTOR}:/etc/opendkim/keys/${DKIM_DOMAIN}/${SELECTOR}.private"
  if [[ ! -f "/tmp/docker-mailserver/opendkim/KeyTable" ]]; then
    _log 'debug' 'Creating DKIM KeyTable'
    echo "${KEYTABLEENTRY}" >/tmp/docker-mailserver/opendkim/KeyTable
  else
    if ! grep -q "${KEYTABLEENTRY}" "/tmp/docker-mailserver/opendkim/KeyTable"; then
      echo "${KEYTABLEENTRY}" >>/tmp/docker-mailserver/opendkim/KeyTable
    fi
  fi

  # write to SigningTable if necessary
  SIGNINGTABLEENTRY="*@${DKIM_DOMAIN} ${SELECTOR}._domainkey.${DKIM_DOMAIN}"
  if [[ ! -f /tmp/docker-mailserver/opendkim/SigningTable ]]; then
    _log 'debug' 'Creating DKIM SigningTable'
    echo "*@${DKIM_DOMAIN} ${SELECTOR}._domainkey.${DKIM_DOMAIN}" >/tmp/docker-mailserver/opendkim/SigningTable
  else
    if ! grep -q "${SIGNINGTABLEENTRY}" /tmp/docker-mailserver/opendkim/SigningTable; then
      echo "${SIGNINGTABLEENTRY}" >>/tmp/docker-mailserver/opendkim/SigningTable
    fi
  fi
done < <(_get_valid_lines_from_file "${DATABASE_VHOST}")

# create TrustedHosts if missing
if [[ -d /tmp/docker-mailserver/opendkim ]] && [[ ! -f /tmp/docker-mailserver/opendkim/TrustedHosts ]]; then
  _log 'debug' 'Creating DKIM TrustedHosts'
  echo "127.0.0.1" >/tmp/docker-mailserver/opendkim/TrustedHosts
  echo "localhost" >>/tmp/docker-mailserver/opendkim/TrustedHosts
fi