<?php
/**
 * antibot.php
 *
 * Script that protect php scripts avoiding brute force attacks to them.
 * It sends a 404 error page response when a new IP is connected
 * and forces to click a link to continue (human response)
 *
 * Copyright (C) 2014 masterguru.net
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */

 /**
 * Usage:
 * 1 - Copy this file in same folder as your login script
 * 2 - Add this line at top of your login script file:

 include('antibot.php');

 * TIP: You can rename this script to any another name to avoid bots
 * could test if it exists.  Be sure to change the include() file name in
 * your login script if done.
 *
 * Todo:
 * - In Apache add persistent IPs in .htaccess with deny to save more resources.
 */

/**
 * Configuration
 */
$langcode = 'en'; // Default language. See Translations below
$wl       = '.ht_whitelist'; // whitelist file. Use .ht prefix in apache

/**
 * Translations
 */
$langs = array(
    'English' => 'en'
);

/**
 * Vars needed automatically replaced:
 * lang_output
 * curpagename
 * query_string
 * actionname
 *
 */

$get_msg['en'] = '<h1>WARNING! Are you human?</h1>
    {lang_output}
    <p>This is first time you try to access to this page from your current IP (connection).</p>
    <p>Press button to continue. You won\'t see again this warning from this IP.</p>
    <form method="POST" action="{curpagename}">
      <input type="hidden" name="query_string" value="{query_string}">
      <input type="hidden" name="actionname" value="{actionname}" />
      <input type="submit" value="Click here to continue"/>
    </form>';



/** DO NOT MODIFY UNDER THIS LINE **/

/* Selected language */
if (isset($_POST['langcode'])) {
    $langcode = $_POST['langcode'];
}

/* Get translations buttons */
/*$lang_output = '';
*foreach ($langs as $langname => $langcoded) {
*   $lang_output .= '<form method="POST" style="float:left;"><input type="hidden" name="langcode" value="' . $langcoded . '" /><input *type="submit" value="' . $langname . '"/></form>';
*}
$lang_output .= '<div style="clear:both"></div>';*/

/**
 * FUNCTIONS
 */

/**
 * Get html header
 */
function _get_header()
{
    $page_header = '
<html>
<head>
<title>Antibot Protection</title>
<meta charset="UTF-8" />
</head>
<body>
  ';
    return $page_header;
}

/**
 * Get html footer
 */
function _get_footer()
{
    $page_footer = '
<hr />
<p style="font-size:80%">AntiBot by <a target="_blank" href="http://minify.cf">onEnabled</a></p>
</body>
</html>';
    return $page_footer;
}

/**
 * Try to get current IP from current request
 */
function getRealIP()
{
    $client_ip = (!empty($_SERVER['REMOTE_ADDR'])) ? $_SERVER['REMOTE_ADDR'] : ((!empty($_ENV['REMOTE_ADDR'])) ? $_ENV['REMOTE_ADDR'] : "unknown");
    if (isset($_SERVER['HTTP_X_FORWARDED_FOR'])) {
        $entries = mb_split('[, ]', $_SERVER['HTTP_X_FORWARDED_FOR']);
        reset($entries);
        while (list(, $entry) = each($entries)) {
            $entry = trim($entry);
            if (preg_match("/^([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)/", $entry, $ip_list)) { // http://www.faqs.org/rfcs/rfc1918.html
                $private_ip = array(
                    '/^0\./',
                    '/^127\.0\.0\.1/',
                    '/^192\.168\..*/',
                    '/^172\.((1[6-9])|(2[0-9])|(3[0-1]))\..*/',
                    '/^10\..*/'
                );
                $found_ip   = preg_replace($private_ip, $client_ip, $ip_list[1]);
                if ($client_ip != $found_ip) {
                    $client_ip = $found_ip;
                    break;
                }
            }
        }
    }
    return $client_ip;
}

/**
 * Get protected script name
 */
function curPageName()
{
    return substr($_SERVER["SCRIPT_NAME"], strrpos($_SERVER["SCRIPT_NAME"], "/") + 1);
}

/**
 * Get url path of protected script name
 */
function curPathURL()
{
    $pageURL = 'http';
    if ($_SERVER["HTTPS"] == "on") {
        $pageURL .= "s";
    }
    $pageURL .= "://";
    if ($_SERVER["SERVER_PORT"] != "80") {
        $pageURL .= $_SERVER["SERVER_NAME"] . ":" . $_SERVER["SERVER_PORT"];
    } else {
        $pageURL .= $_SERVER["SERVER_NAME"];
    }
    $parts = explode('/', $_SERVER['REQUEST_URI']);
    for ($i = 0; $i < count($parts) - 1; $i++) {
        $pageURL .= $parts[$i] . "/";
    }
    return $pageURL;
}

/**
 * Block access
 */
function blocked($get_msg, $langcode, $lang_output, $actionname)
{
    $data    = array(
        'lang_output' => $lang_output,
        'curPageName' => curPageName(),
        'actionname' => $actionname,
        'query_string' => $_SERVER['QUERY_STRING']
    );
    $content = replace_vars($get_msg[$langcode], $data);
    header("HTTP/1.0 404 Not Found");
    die(_get_header() . $content . _get_footer());
}

/**
 * Replace {vars} in translations
 */
function replace_vars($buffer, $data)
{
    /* replace declared var names */
    foreach ($data as $k => $v) {
        if (is_string($v) || is_numeric($v) || $v == NULL) {
            $buffer = preg_replace('/\{' . strtolower($k) . '\}/', $v, $buffer);
        }
    }
    return $buffer;
}

/** END FUNCTIONS ****/

/**
 * Vars
 */
$requester_IP = getRealIP(); // current requester IP
$wl_filename  = dirname(__FILE__) . '/' . $wl; // set full path whitelist file

/* Create/Open session */
session_start();

/* Check actionname */
if (isset($_SESSION['actionname']) AND isset($_POST['actionname'])) {

    if ($_SESSION['actionname'] == $_POST['actionname']) {

        /* Add IP to whitelist */
        $fh = fopen($wl_filename, 'a');
        fwrite($fh, $requester_IP . "\n");
        fclose($fh);

        /* Destroy current session */
        $_SESSION = array(); // destroys sesion parameters
        $_COOKIE  = array(); // destroys cookies parameters
        session_destroy();

        /* Redirects to protected script */
        if (!empty($_POST['query_string'])) {
            header('Location: ' . curPathURL() . curPageName() . '?' . $_POST['query_string']);
        } else {
            header('Location: ' . curPathURL() . curPageName());
        }
        die();

    } else {

        /* Get current actionname session */
        $actionname = $_SESSION['actionname'];

    }

} else {

    /* Create new actionname session */
    $actionname             = '.ht_' . uniqid();
    $_SESSION['actionname'] = $actionname;

}

/* Check whitelist */
if (is_file($wl_filename)) {
    $whitelist = file($wl_filename, FILE_IGNORE_NEW_LINES);

    /* is IP in whitelist? */
    if (!in_array($requester_IP, $whitelist)) {
        blocked($get_msg, $langcode, $lang_output, $actionname);
    }

} else {

    /* Empty whitelist */
    blocked($get_msg, $langcode, $lang_output, $actionname);

}
// Lets continue loading protected script
?>