Organizr/auth.php

<?php

$data = false;

function getBannedUsers($string){
    if (strpos($string, ',') !== false) {
        $banned = explode(",", $string);     
    }else{
        $banned = array($string);  
    }
    return $banned;
}

function getWhitelist($string){
    if (strpos($string, ',') !== false) {
        $whitelist = explode(",", $string); 
    }else{
        $whitelist = array($string);
    }
    foreach($whitelist as &$ip){
        $ip = is_numeric(substr($ip, 0, 1)) ? $ip : gethostbyname($ip);
    }
    return $whitelist;
}

if (isset($_GET['ban'])) : $ban = strtoupper($_GET['ban']); else : $ban = ""; endif;
if (isset($_GET['whitelist'])) : $whitelist = strtoupper($_GET['whitelist']); else : $whitelist = ""; endif;
$currentIP = $_SERVER['REMOTE_ADDR'];

require_once("user.php");
$USER = new User("registration_callback");

if (isset($_GET['admin'])) :

    if($USER->authenticated && $USER->role == "admin" && !in_array(strtoupper($USER->username), getBannedUsers($ban))) :

        exit(http_response_code(200));

    else :

        exit(http_response_code(401));

    endif;

elseif (isset($_GET['user'])) :

    if($USER->authenticated && !in_array(strtoupper($USER->username), getBannedUsers($ban))) :

        exit(http_response_code(200));

    else :

        exit(http_response_code(401));

    endif;

elseif (isset($_GET['whitelist'])) :

    if(in_array($currentIP, getWhitelist($whitelist))) :
       
       exit(http_response_code(200));
       
    else :

        exit(http_response_code(401));

    endif;

elseif (!isset($_GET['user']) && !isset($_GET['admin']) && !isset($_GET['whitelist'])) :

    exit(http_response_code(401));

endif;

?>