#!/usr/bin/env bash

# disable a user by removing them from the sshallow/sshforward group
# and move them to the sshreject group
# Note that call is ./lock_user.sh -t <user 1> <user 2> ...
# if the -t is not in the first position it will be ignored

# SET TO 1 to TEST [will not move user in groups]
TEST=0; # no delete, just print
while getopts ":t" opt; do
	case "${opt}" in
		t|test)
			TEST=1;
			;;
	esac;
done;
shift "$((OPTIND-1))"

if [ $(whoami) != "root" ]; then
	if [ ${TEST} -eq 0 ]; then
		echo "Script must be run as root user";
		exit;
	else
		echo "!!!! Script must be run as root user !!!!";
	fi;
fi;

if [ $# -eq 0 ]; then
	echo "Must give at least one user name";
	exit;
fi;

# ignore users (root and admin users)
ignore_users=('root' 'ec2-user' 'ubuntu' 'admin');
# ssh reject group
ssh_reject_group="sshreject";
if [ -z $(cat /etc/group | grep "${ssh_reject_group}:") ]; then
	echo "Missing ssh reject group: ${ssh_reject_group}";
	exit;
fi;
ssh_allow_group="sshallow";
ssh_forward_group="sshfoward";
user_group_tpl="gpasswd -d %s %s\ngpasswd -a %s %s\n";

echo "--------------------->"
# $1 ... $n
for username in "$@"; do
	# skip if there is an option hidden
	if [[ ${_arg:0:1} = "-" ]]; then
		continue;
	fi;
	# skip ignore users, note that if a user is not in the sshallow list anyway
	# we skip them too, this is just in case check
	if [[ " ${ignore_users[*]} " =~ " ${username} " ]]; then
		echo "[!] User $username is in the ignore user list";
		continue;
	fi;
	# check that user exists in passwd
	if ! id "${username}" &>/dev/null; then
		echo "[!] User $username does not exists in /etc/passwd file";
		continue;
	fi;
	# if not check if in reject list
	if id -nGz "${username}" | grep -qzxF "${ssh_reject_group}"; then
		echo "[.] User $username already in the ${ssh_reject_group} list";
		continue;
	fi;
	# check if user is in sshallow/forward list
	ssh_remove_group='';
	if id -nGz "${username}" | grep -qzxF "${ssh_allow_group}"; then
		ssh_remove_group="${ssh_allow_group}";
	fi;
	# if user is in ssh allow group and ALSO in ssh forward group -> bad
	if id -nGz "${username}" | grep -qzxF "${ssh_forward_group}"; then
		if [ ! -z "${ssh_remove_group}" ]; then
			echo "[!!!! ERROR !!!!] User $username exists in both ${ssh_allow_group} and ${ssh_forward_group} group which should not be allowed. Remove user from one group and run script again.";
			break;
		fi;
		ssh_remove_group="${ssh_forward_group}";
	fi;
	if [ ! -z "${ssh_remove_group}" ]; then
		# remove user from ssh group and add to reject groups
		echo "[*] User $username will be removed from ${ssh_remove_group}";
		if [ ${TEST} -eq 1 ]; then
			printf "${user_group_tpl}" "${username}" "${ssh_remove_group}" "${username}" "${ssh_reject_group}";
		else
			gpasswd -d "${username}" "${ssh_remove_group}";
			gpasswd -a "${username}" "${ssh_reject_group}";
		fi;
	else
		# skip not ssh user
		echo "[?] User $username not in any ssh allow/foward groups";
	fi;
done;

# __END__