shell bypass 403
<?php
/**
* Part of the Joomla Framework Utilities Package
*
* @copyright Copyright (C) 2010-2016 Nicholas K. Dionysopoulos / Akeeba Ltd. All rights reserved.
* @license GNU General Public License version 2 or later; see LICENSE.txt
* @note This file has been modified by the Joomla! Project and no longer reflects the original work of its author.
*/
namespace Joomla\Utilities;
/**
* IpHelper is a utility class for processing IP addresses
*
* @since 1.6.0
*/
final class IpHelper
{
/**
* The IP address of the current visitor
*
* @var string
* @since 1.6.0
*/
private static $ip = null;
/**
* Should I allow IP overrides through X-Forwarded-For or Client-Ip HTTP headers?
*
* @var boolean
* @since 1.6.0
* @note The default value is false in version 2.0+
*/
private static $allowIpOverrides = false;
/**
* Private constructor to prevent instantiation of this class
*
* @since 1.6.0
*/
private function __construct()
{
}
/**
* Get the current visitor's IP address
*
* @return string
*
* @since 1.6.0
*/
public static function getIp()
{
if (self::$ip === null) {
$ip = static::detectAndCleanIP();
if (!empty($ip) && ($ip != '0.0.0.0') && \function_exists('inet_pton') && \function_exists('inet_ntop')) {
$myIP = @inet_pton($ip);
if ($myIP !== false) {
$ip = inet_ntop($myIP);
}
}
static::setIp($ip);
}
return self::$ip;
}
/**
* Set the IP address of the current visitor
*
* @param string $ip The visitor's IP address
*
* @return void
*
* @since 1.6.0
*/
public static function setIp($ip)
{
self::$ip = $ip;
}
/**
* Is it an IPv6 IP address?
*
* @param string $ip An IPv4 or IPv6 address
*
* @return boolean
*
* @since 1.6.0
*/
public static function isIPv6($ip)
{
return strpos($ip, ':') !== false;
}
/**
* Checks if an IP is contained in a list of IPs or IP expressions
*
* @param string $ip The IPv4/IPv6 address to check
* @param array|string $ipTable An IP expression (or a comma-separated or array list of IP expressions) to check against
*
* @return boolean
*
* @since 1.6.0
*/
public static function IPinList($ip, $ipTable = '')
{
// No point proceeding with an empty IP list
if (empty($ipTable)) {
return false;
}
// If the IP list is not an array, convert it to an array
if (!\is_array($ipTable)) {
if (strpos($ipTable, ',') !== false) {
$ipTable = explode(',', $ipTable);
$ipTable = array_map('trim', $ipTable);
} else {
$ipTable = trim($ipTable);
$ipTable = [$ipTable];
}
}
// If no IP address is found, return false
if ($ip === '0.0.0.0') {
return false;
}
// If no IP is given, return false
if (empty($ip)) {
return false;
}
// Sanity check
if (!\function_exists('inet_pton')) {
return false;
}
// Get the IP's in_adds representation
$myIP = @inet_pton($ip);
// If the IP is in an unrecognisable format, quite
if ($myIP === false) {
return false;
}
$ipv6 = static::isIPv6($ip);
foreach ($ipTable as $ipExpression) {
$ipExpression = trim($ipExpression);
// Inclusive IP range, i.e. 123.123.123.123-124.125.126.127
if (strstr($ipExpression, '-')) {
list($from, $to) = explode('-', $ipExpression, 2);
if ($ipv6 && (!static::isIPv6($from) || !static::isIPv6($to))) {
// Do not apply IPv4 filtering on an IPv6 address
continue;
}
if (!$ipv6 && (static::isIPv6($from) || static::isIPv6($to))) {
// Do not apply IPv6 filtering on an IPv4 address
continue;
}
$from = @inet_pton(trim($from));
$to = @inet_pton(trim($to));
// Sanity check
if (($from === false) || ($to === false)) {
continue;
}
// Swap from/to if they're in the wrong order
if ($from > $to) {
list($from, $to) = [$to, $from];
}
if (($myIP >= $from) && ($myIP <= $to)) {
return true;
}
} elseif (strstr($ipExpression, '/')) {
// Netmask or CIDR provided
$binaryip = static::inetToBits($myIP);
list($net, $maskbits) = explode('/', $ipExpression, 2);
if ($ipv6 && !static::isIPv6($net)) {
// Do not apply IPv4 filtering on an IPv6 address
continue;
}
if (!$ipv6 && static::isIPv6($net)) {
// Do not apply IPv6 filtering on an IPv4 address
continue;
}
if ($ipv6 && strstr($maskbits, ':')) {
// Perform an IPv6 CIDR check
if (static::checkIPv6CIDR($myIP, $ipExpression)) {
return true;
}
// If we didn't match it proceed to the next expression
continue;
}
if (!$ipv6 && strstr($maskbits, '.')) {
// Convert IPv4 netmask to CIDR
$long = ip2long($maskbits);
$base = ip2long('255.255.255.255');
$maskbits = 32 - log(($long ^ $base) + 1, 2);
}
// Convert network IP to in_addr representation
$net = @inet_pton($net);
// Sanity check
if ($net === false) {
continue;
}
// Get the network's binary representation
$expectedNumberOfBits = $ipv6 ? 128 : 24;
$binarynet = str_pad(static::inetToBits($net), $expectedNumberOfBits, '0', STR_PAD_RIGHT);
// Check the corresponding bits of the IP and the network
$ipNetBits = substr($binaryip, 0, $maskbits);
$netBits = substr($binarynet, 0, $maskbits);
if ($ipNetBits === $netBits) {
return true;
}
} else {
// IPv6: Only single IPs are supported
if ($ipv6) {
$ipExpression = trim($ipExpression);
if (!static::isIPv6($ipExpression)) {
continue;
}
$ipCheck = @inet_pton($ipExpression);
if ($ipCheck === false) {
continue;
}
if ($ipCheck == $myIP) {
return true;
}
} else {
// Standard IPv4 address, i.e. 123.123.123.123 or partial IP address, i.e. 123.[123.][123.][123]
$dots = 0;
if (substr($ipExpression, -1) == '.') {
// Partial IP address. Convert to CIDR and re-match
foreach (count_chars($ipExpression, 1) as $i => $val) {
if ($i == 46) {
$dots = $val;
}
}
switch ($dots) {
case 1:
$netmask = '255.0.0.0';
$ipExpression .= '0.0.0';
break;
case 2:
$netmask = '255.255.0.0';
$ipExpression .= '0.0';
break;
case 3:
$netmask = '255.255.255.0';
$ipExpression .= '0';
break;
default:
$dots = 0;
}
if ($dots) {
$binaryip = static::inetToBits($myIP);
// Convert netmask to CIDR
$long = ip2long($netmask);
$base = ip2long('255.255.255.255');
$maskbits = 32 - log(($long ^ $base) + 1, 2);
$net = @inet_pton($ipExpression);
// Sanity check
if ($net === false) {
continue;
}
// Get the network's binary representation
$expectedNumberOfBits = $ipv6 ? 128 : 24;
$binarynet = str_pad(static::inetToBits($net), $expectedNumberOfBits, '0', STR_PAD_RIGHT);
// Check the corresponding bits of the IP and the network
$ipNetBits = substr($binaryip, 0, $maskbits);
$netBits = substr($binarynet, 0, $maskbits);
if ($ipNetBits === $netBits) {
return true;
}
}
}
if (!$dots) {
$ip = @inet_pton(trim($ipExpression));
if ($ip == $myIP) {
return true;
}
}
}
}
}
return false;
}
/**
* Works around the REMOTE_ADDR not containing the user's IP
*
* @return void
*
* @since 1.6.0
*/
public static function workaroundIPIssues()
{
$ip = static::getIp();
if (isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] === $ip) {
return;
}
if (isset($_SERVER['REMOTE_ADDR'])) {
$_SERVER['JOOMLA_REMOTE_ADDR'] = $_SERVER['REMOTE_ADDR'];
} elseif (\function_exists('getenv')) {
if (getenv('REMOTE_ADDR')) {
$_SERVER['JOOMLA_REMOTE_ADDR'] = getenv('REMOTE_ADDR');
}
}
$_SERVER['REMOTE_ADDR'] = $ip;
}
/**
* Should I allow the remote client's IP to be overridden by an X-Forwarded-For or Client-Ip HTTP header?
*
* @param boolean $newState True to allow the override
*
* @return void
*
* @since 1.6.0
*/
public static function setAllowIpOverrides($newState)
{
self::$allowIpOverrides = $newState ? true : false;
}
/**
* Gets the visitor's IP address.
*
* Automatically handles reverse proxies reporting the IPs of intermediate devices, like load balancers. Examples:
*
* - https://www.akeebabackup.com/support/admin-tools/13743-double-ip-adresses-in-security-exception-log-warnings.html
* - https://stackoverflow.com/questions/2422395/why-is-request-envremote-addr-returning-two-ips
*
* The solution used is assuming that the last IP address is the external one.
*
* @return string
*
* @since 1.6.0
*/
protected static function detectAndCleanIP()
{
$ip = static::detectIP();
if (strstr($ip, ',') !== false || strstr($ip, ' ') !== false) {
$ip = str_replace(' ', ',', $ip);
$ip = str_replace(',,', ',', $ip);
$ips = explode(',', $ip);
$ip = '';
while (empty($ip) && !empty($ips)) {
$ip = array_shift($ips);
$ip = trim($ip);
}
} else {
$ip = trim($ip);
}
return $ip;
}
/**
* Gets the visitor's IP address
*
* @return string
*
* @since 1.6.0
*/
protected static function detectIP()
{
// Normally the $_SERVER superglobal is set
if (isset($_SERVER)) {
// Do we have an x-forwarded-for HTTP header (e.g. NginX)?
if (self::$allowIpOverrides && isset($_SERVER['HTTP_X_FORWARDED_FOR'])) {
return $_SERVER['HTTP_X_FORWARDED_FOR'];
}
// Do we have a client-ip header (e.g. non-transparent proxy)?
if (self::$allowIpOverrides && isset($_SERVER['HTTP_CLIENT_IP'])) {
return $_SERVER['HTTP_CLIENT_IP'];
}
// Normal, non-proxied server or server behind a transparent proxy
if (isset($_SERVER['REMOTE_ADDR'])) {
return $_SERVER['REMOTE_ADDR'];
}
}
/*
* This part is executed on PHP running as CGI, or on SAPIs which do not set the $_SERVER superglobal
* If getenv() is disabled, you're screwed
*/
if (!\function_exists('getenv')) {
return '';
}
// Do we have an x-forwarded-for HTTP header?
if (self::$allowIpOverrides && getenv('HTTP_X_FORWARDED_FOR')) {
return getenv('HTTP_X_FORWARDED_FOR');
}
// Do we have a client-ip header?
if (self::$allowIpOverrides && getenv('HTTP_CLIENT_IP')) {
return getenv('HTTP_CLIENT_IP');
}
// Normal, non-proxied server or server behind a transparent proxy
if (getenv('REMOTE_ADDR')) {
return getenv('REMOTE_ADDR');
}
// Catch-all case for broken servers, apparently
return '';
}
/**
* Converts inet_pton output to bits string
*
* @param string $inet The in_addr representation of an IPv4 or IPv6 address
*
* @return string
*
* @since 1.6.0
*/
protected static function inetToBits($inet)
{
if (\strlen($inet) == 4) {
$unpacked = unpack('A4', $inet);
} else {
$unpacked = unpack('A16', $inet);
}
$unpacked = str_split($unpacked[1]);
$binaryip = '';
foreach ($unpacked as $char) {
$binaryip .= str_pad(decbin(\ord($char)), 8, '0', STR_PAD_LEFT);
}
return $binaryip;
}
/**
* Checks if an IPv6 address $ip is part of the IPv6 CIDR block $cidrnet
*
* @param string $ip The IPv6 address to check, e.g. 21DA:00D3:0000:2F3B:02AC:00FF:FE28:9C5A
* @param string $cidrnet The IPv6 CIDR block, e.g. 21DA:00D3:0000:2F3B::/64
*
* @return boolean
*
* @since 1.6.0
*/
protected static function checkIPv6CIDR($ip, $cidrnet)
{
$ip = inet_pton($ip);
$binaryip = static::inetToBits($ip);
list($net, $maskbits) = explode('/', $cidrnet);
$net = inet_pton($net);
$binarynet = static::inetToBits($net);
$ipNetBits = substr($binaryip, 0, $maskbits);
$netBits = substr($binarynet, 0, $maskbits);
return $ipNetBits === $netBits;
}
}