docker-mailserver/target/bin/open-dkim

#!/bin/bash

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

KEYSIZE=4096
SELECTOR=mail
DOMAINS=

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

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

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

${ORANGE}DESCRIPTION${RESET}
    Configures DKIM keys. OPTIONS can be used to configure a more complex setup.
    LDAP setups require these options.

${ORANGE}OPTIONS${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 are 1024, 2048 and 4096 (default).
        selector   Set a manual selector (default is 'mail') for the key. (${LCYAN}ATTENTION${RESET}: NOT IMPLEMENTED YET!)
        domain     Provide the domain(s) for which keys are to be generated.

${ORANGE}EXAMPLES${RESET}
    ${LWHITE}./setup.sh config dkim keysize 2048${RESET}
        Creates keys of length 2048 bit in a default setup where domains are obtained from
        your accounts.

    ${LWHITE}./setup.sh config dkim keysize 2048 selector 2021-dkim${RESET}
        Creates keys of length 2048 bit in a default setup where domains are obtained from
        your accounts. The DKIM selector used is '2021-dkim'.

    ${LWHITE}./setup.sh config dkim keysize 2048 selector 2021-dkim domain 'whoami.com,whoareyou.org'${RESET}
        Appropriate for an LDAP setup. Creates keys of length 2048 bit in a default setup
        where domains are obtained from your accounts. The DKIM selector used is '2021-dkim'.
        The domains for which DKIM keys are generated are 'whoami.com' and 'whoareyou.org'.

${ORANGE}EXIT STATUS${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.

"
}

[[ ${1:-} == 'help' ]] && { __usage ; exit 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

  # 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