#!/usr/bin/env bash

#####################################################
# This script require the following
#
# * A path structure like this:
# 	[..path..]/<domainname.tld>/
# * This path contains a zone file named `db`
#
# Your named.conf.local file must link to a
# filed named `db.signed`, e.g
#
# zone "domain.tld" {
# 	type master;
# 	file "[..path..]/domain.tld/db.signed";
# };
#
# USAGE: 
#
# 1. Make `dnssec-signer` executable:
# 	chmod +x /path/to/dnssec-signer
# 
# 2. Run:
# 	./path/to/dnssec-signer <domain.tld>
# 3. Or, for every domain in path
# 	./path/to/dnssec-signer
#
######################################################

SELF="$(basename ${0})"

######################################################
# 		  START OF CONFIG		     #
######################################################
# SET YOU SYSTEM SPECIFIC DATA (which systemctl e.g) #

NAMEDZONES="/etc/bind/named.conf.local"
ZONESDIR="/etc/bind/zones"
CHECKZONE=/usr/sbin/named-checkzone
CHECKCONF=/usr/sbin/named-checkconf
KEYGEN=/usr/sbin/dnssec-keygen
SIGNZONE=/usr/sbin/dnssec-signzone
SYSCTL=/bin/systemctl
JOURCTL=/bin/journalctl
DNSSERVICE="bind9.service"
LOGGER=/usr/bin/logger
LOGGERFLAGN="-t $(whoami) -p daemon.info"
LOGGERFLAGE="-t $(whoami) -p daemon.err"

######################################################
# 	   	    END OF CONFIG		     #
######################################################

function error_msg {
	FOR=${1}
	ERRMSG="${2}"
	echo -e "\e[31m[${SELF}:\e[1m${FOR}\e[21m]:\e[0m ${ERRMSG}"
	${LOGGER} ${LOGGERFLAGE} "[${SELF}:${FOR}]: ${ERRMSG}"
}

function note_msg {
	FOR=${1}
	NOTEMSG="${2}"
	echo -e "\e[32m[${SELF}:\e[1m${FOR}\e[21m]:\e[0m ${NOTEMSG}"
	${LOGGER} ${LOGGERFLAGN} "[${SELF}:${FOR}]: ${NOTEMSG}"
}

# Generating keys for zone
# Note, this doesnt check if they exists!
function genkeys {
	ZONE=${1}
	note_msg "${ZONE}" "Generating missing ZSK and KSK"

	${KEYGEN} -a NSEC3RSASHA1 -b 2048 -n ZONE "${ZONE}"
	if [ $? -ne 0 ]; then
		error_msg "${ZONE}" "Failed to generate Zone Signing Key (ZSK)"
		return 1
	fi

	${KEYGEN} -f KSK -a NSEC3RSASHA1 -b 4096 -n ZONE "${ZONE}"
	if [ $? -ne 0 ]; then
		error_msg "${ZONE}" "Failed to generate Key Signing Key (KSK)"
		return 1
	fi
	
	note_msg "${ZONE}" "ZSK and KSK generated"
	return 0
}

# Sign zone
# The actual signing process.
function sign {
	ZONE="${1}"
	note_msg "${ZONE}" "Signing ZONE"

	if ! [ -d "${2}" ]; then
		error_msg "${ZONE}" "Path ${2} doesnt exist"
		return 1
	fi

	cd "${2}"
	echo `pwd`

	F="db"

	if ! [ -w "${F}" ]; then
		error_msg "${ZONE}" "Missing $(pwd)/${F}"
		return 1
	fi

	ZONEF="db.zone"
	ZONEINCF="${ZONEF}.include"

	note_msg "${ZONE}" "Validating unsigned zone file"
	${CHECKZONE} "${ZONE}" "${F}"

	if [ $? -ne 0 ]; then
		error_msg "${ZONE}" "Error(s) in zone file"
		if [ -r "${ZONEF}" ]; then
			note_msg "${ZONE}" "Existing signed zone, allowing restart"
			return 1
		else
			note_msg "${ZONE}" "No existing signed zone, disallowing restart"
			return 2
		fi
	fi
	
	KEYS=()
	
	for KEY in $(ls "./"); do
		if [[ "${KEY}" == "K${ZONE}"* ]] && [[ "${KEY}" == *key ]]; then
			KEYS[${#KEYS[@]}]="${KEY}"
		fi
	done
	
	if [ "${#KEYS[@]}" -ne 2 ]; then
		if [ "${#KEYS[@]}" -ne 0 ]; then
			rm "${KEYS[@]}"
		fi

		genkeys "${ZONE}"
		if [ $? -ne 0 ]; then
			return 1
		fi

		sign "${ZONE}" "${2}"
		return $?
	fi

	cat "${F}" > "${ZONEINCF}"
	for KEY in "${KEYS[@]}"; do
		echo "\$INCLUDE ${KEY}" >> "${ZONEINCF}"
	done

	SALT=$(head -c 1000 /dev/random | sha1sum | cut -b 1-16)
	${SIGNZONE} -A -3 "${SALT}" -N increment -f "${ZONEF}" -o "${ZONE}" -t "${ZONEINCF}"

	if [ $? -ne 0 ]; then
		error_msg "${ZONE}" "Error signing zone"
		return 2
	fi

	note_msg "${ZONE}" "Checking zone-file"
	${CHECKZONE} "${ZONE}" "${ZONEF}"
	if [ $? -ne 0 ]; then
		error_msg "${ZONE}" "Error zone-file'${SONEF}'"
		return 2
	fi
	note_msg "${ZONE}" "Signing successul!"
	return 0
}

# Sign zone;
# Checks that dir exists first...
# and ensures we're entering and leaving correctly
function signzone {
	SIGN="${1}"
	CWDIR=$(pwd)
	sign "${1}" "${ZONESDIR}/${SIGN}"
	RET=$?
	cd "${CWDIR}"
	return ${RET}
}

note_msg "date" "$(date)"
if [[ ${EUID} -ne 0 ]]; then
	error_msg "${USER}" "Must execute file as root."
	exit 1
fi

# Collect arguments (zones)
ZONES="${*}"
IFS=' ', read -r -a ZONES <<< "${ZONES}"

if [ ${#ZONES[@]} -ne 0 ]; then
	note_msg "${#ZONES[@]}" "Start signing zones"  
	ERR=0
	for ZONE in "${ZONES[@]}"; do
		signzone "${ZONE}"
		if [ $? -eq 2 ]; then
			# To prevent restarting dns if failure
			ERR=1
		fi
	done;

	if [ ${ERR} -eq 0 ]; then
		${CHECKCONF}
		if [ $? -ne 0 ]; then
			error_msg "${CHECKCONF}" "Error in configruation, not reloading"
		else
			note_msg "$(basename ${SYSCTL})" "Restarting ${DNSSERVICE}"
			${SYSCTL} restart "${DNSSERVICE}"
			if [ $? -ne 0 ]; then
				${JOURCTL} -n 10 --unit "${DNSSERVICE}" | xargs -0
			fi
		fi
	else
		error_msg "${DNSSERVICE}" "Errors in configuration(s) for zone(s), not restarting."
	fi
else
	note_msg "${ZONESDIR}" "Finding zones to sign corresponding to ${NAMEDZONES}"
	CWD=$(pwd)
	cd "${ZONESDIR}"
	NAMED=$(cat $NAMEDZONES)
	for ZONE in $(ls -d */); do
		ACTIVE=$(cat $NAMEDZONES | grep "\"$(basename ${ZONE})\"" | tr -d '[:space:]')
		if [[ "${ACTIVE}" == zone* ]]; then
			ZONES[${#ZONES[@]}]=$(basename ${ZONE})
		fi
	done
	cd ${CWD}
	note_msg "" "Found ${#ZONES[@]} zone(s) active"
	if [ "${#ZONES[@]}" -ne 0 ]; then
		${SELF} "${ZONES[@]}"
	fi
fi