SSH-Rotate-Keys/bin/user-add-ssh-key.sh

#!/usr/bin/env bash

# Add user key to admin SSH KEY LIST

# base folder for all data
BASE_FOLDER=$(dirname "$(readlink -f "$0")")"/";
# config folder
CONFIG_BASE="${BASE_FOLDER}../config/";
# current public key folder for user
SSH_PUBLIC_KEYS_CURRENT="${BASE_FOLDER}../ssh-public-keys/user-current/";

DRY_RUN=0;
GO=0;
HOST_ONLY="";
USER_ONLY="";
USER_PUBLIC_KEY="";
#
while getopts ":h:u:k:ng" opt; do
	case "${opt}" in
		h) # hostname
			HOST_ONLY="${OPTARG}";
			;;
		u) # username
			USER_ONLY="${OPTARG}";
			;;
		k) # user public key
			USER_PUBLIC_KEY="${OPTARG}";
			;;
		n) # dry-run
			DRY_RUN=1;
			;;
		g) # go
			GO=1;
			;;
		\?)
			echo -e "\n Option does not exist: ${OPTARG}\n";
			echo "-h override single host name";
			echo "-u override user name for a host";
			echo "-k public key file to add";
			echo "-n dry run";
			echo "-g flag for actual change call";
			echo ""
			exit 1;
			;;
	esac
done

# the public key file for the user
SSH_KEY_PUB_FILE="${SSH_PUBLIC_KEYS_CURRENT}${USER_PUBLIC_KEY}" ;

# no current public key file with given name
if [ ! -f "${SSH_KEY_PUB_FILE}" ]; then
	echo "Missing user ssh public key file to add: ${SSH_KEY_PUB_FILE}";
	exit;
else
	# validate key
	SSH_PUBLIC_KEY_VALIDATE="ssh-keygen -l -f";
	# message=$(${SSH_PUBLIC_KEY_VALIDATE} "${SSH_KEY_PUB_FILE}");
	if ! message=$(${SSH_PUBLIC_KEY_VALIDATE} "${SSH_KEY_PUB_FILE}" 2>&1); then
		echo "Failed to parse ssh public key: ${message}";
		exit;
	fi;
fi

# load config
if [ ! -f "${CONFIG_BASE}settings.ini" ]; then
	echo "Missing 'settings.ini' file in ${CONFIG_BASE}";
	exit;
fi
# shellcheck source=../config/settings.ini
# shellcheck disable=SC1094
source <(grep "=" "${CONFIG_BASE}settings.ini" | sed 's/ *= */=/g')
if [ -z "${server_list}" ]; then
	echo "No server list is defined in the settings";
	exit;
fi;
# we must have "server_list" set and file must be in config folder
if [ ! -f "${CONFIG_BASE}${server_list}" ]; then
	echo "Cannot find ${server_list} file in the config folder";
	exit
fi
# abort if go not set
if [ ${GO} -eq 0 ] && [ ${DRY_RUN} -eq 1 ]; then
	GO=1;
elif [ ${GO} -eq 0 ]; then
	echo "No -g (go) parameter set. aborting. For testing set -n for dry run"
	exit;
fi

# default ssh command
# -t is needed for systens when "Defaults    requiretty" is set
SSH="ssh -a -x -n";

# Add the SSH Key to an auth file if it does not exist yet and the auth file does exist
# Build bash command to run this
# @Params
# AUTH_KEY_FILE {1}: the auth key file where to add the key
# PUB_KEY_FILE {2}: Public key file name
add_ssh_key() {
	AUTH_KEY_FILE="${1}";
	PUB_KEY_FILE="${2}";
	AUTH_KEY_SETTINGS="${3}";
	RMV_CHATTR_I="chattr -i"
	ADD_CHATTR_I="chattr +i"
	RMV_CHMOD_UW="chmod u-w"
	ADD_CHMOD_UW="chmod u+w"
	# check if the auth file exists and the key is not yet in the auth file
	# the -z `tail ...` checks for a trailing newline. The echo adds one if was missing (from ssh-copy-id)
	# PROBLEM:
	# for grep from pipe, the left data is removed. we also can't cat from pipe
	# into a var as that would go through a pipe and not be visible
	# so we get the pub key file name and read it here
	pub_key=$(cat "${PUB_KEY_FILE}");
	# if we have auth key settings, prefix them to the pub key
	# Note that the check key "pub_key" ignores any prefixes, but we add with settings prefix
	if [ -n "${AUTH_KEY_SETTINGS}" ]; then
		pub_key_write="${AUTH_KEY_SETTINGS} ${pub_key}";
	else
		pub_key_write="${pub_key}";
	fi
	INSTALLKEYS_SH=$(tr '\t\n' ' ' <<-EOF
		if [ -f "${AUTH_KEY_FILE}" ] && ! grep "${pub_key}" "${AUTH_KEY_FILE}" >> /dev/null; then
			${RMV_CHATTR_I} "${AUTH_KEY_FILE}";
			${ADD_CHMOD_UW} "${AUTH_KEY_FILE}";
			{ [ -z \`tail -1c ${AUTH_KEY_FILE} 2>/dev/null\` ] ||
				echo >> "${AUTH_KEY_FILE}" || exit 1; } &&
				echo "${pub_key_write}" >> "${AUTH_KEY_FILE}" || exit 1;
			${RMV_CHMOD_UW} "${AUTH_KEY_FILE}";
			${ADD_CHATTR_I} "${AUTH_KEY_FILE}";
		else
			echo "[!] Already added";
		fi;
		EOF
	);
	# to defend against quirky remote shells: use 'exec sh -c' to get POSIX;
	printf "exec sudo sh -c '%s'" "${INSTALLKEYS_SH}"
}

# install call
# @Params
# HOSTNAME {1} hostname to access
# USERNAME {2} username to use
# PUB_KEY_FILE {3} public key file to add
# AUTH_KEY_FILE {4} auth key file where to add the public key
install_ssh_key() {
	HOSTNAME="${1}";
	USERNAME="${2}";
	PUB_KEY_FILE="${3}";
	AUTH_KEY_FILE="${4}";
	AUTH_KEY_SETTINGS="${5}";
	echo "[.] Add to auth file: ${AUTH_KEY_FILE}";
	if [ ${DRY_RUN} -eq 0 ]; then
		${SSH} "${USERNAME}"@"${HOSTNAME}" "$(add_ssh_key "${AUTH_KEY_FILE}" "${PUB_KEY_FILE}" "${AUTH_KEY_SETTINGS}")"
	else
		echo "${SSH} \"${USERNAME}\"@\"${HOSTNAME}\" \"\$(add_ssh_key \"${AUTH_KEY_FILE}\" \"${PUB_KEY_FILE}\" \"${AUTH_KEY_SETTINGS}\")\"";
	fi
}

while read -r line; do
	if [[ "${line}" =~ ^\# ]]; then
		continue;
	fi
	# hostname is on pos 1
	hostname=$(echo "${line}" | cut -d "," -f 1);
	# if hostname opt set and not matching skip
	if [ -n "${HOST_ONLY}" ] && [ "${HOST_ONLY}" != "${hostname}" ]; then
		continue;
	fi
	# login user name
	username=$(echo "${line}" | cut -d "," -f 2);
	# if username opt set and not matching skip
	if [ -n "${USER_ONLY}" ] && [ "${USER_ONLY}" != "${username}" ]; then
		continue;
	fi

	echo "[+] Add new public key '${USER_PUBLIC_KEY}' to: ${username}@${hostname}";

	# flags: (not used at the moment)
	# Possible: U (add to .ssh/authorized_keys)
	# flags=$(echo "${line}" | cut -d "," -f 3);
	# auth key settings (in front of auth key)
	auth_key_settings=$(echo "${line}" | cut -d "," -f 4);
	install_ssh_key "${hostname}" "${username}" "${SSH_KEY_PUB_FILE}" "/etc/ssh/authorized_keys/${username}" "${auth_key_settings}";

	echo "[=] ............... DONE";
done <<<"$(sed 1d "${CONFIG_BASE}${server_list}")";

# __END__