rhymix/common/framework/security.php

339 lines
8.3 KiB
PHP

<?php
namespace Rhymix\Framework;
/**
* The security class.
*/
class Security
{
/**
* Sanitize a variable.
*
* @param string $input
* @param string $type
* @return string|false
*/
public static function sanitize($input, $type)
{
switch ($type)
{
// Escape HTML special characters.
case 'escape':
if (!detectUTF8($input)) return false;
return escape($input);
// Strip all HTML tags.
case 'strip':
if (!detectUTF8($input)) return false;
return escape(strip_tags($input));
// Clean up HTML content to prevent XSS attacks.
case 'html':
if (!detectUTF8($input)) return false;
return Security\HTMLFilter::clean($input);
// Clean up the input to be used as a safe filename.
case 'filename':
if (!detectUTF8($input)) return false;
return Security\FilenameFilter::clean($input);
// Unknown filters return false.
default: return false;
}
}
/**
* Encrypt a string using AES.
*
* @param string $plaintext
* @param string $key (optional)
* @param bool $force_compat (optional)
* @return string|false
*/
public static function encrypt($plaintext, $key = null, $force_compat = false)
{
// Get the encryption key.
$key = $key ?: config('crypto.encryption_key');
$key = substr(hash('sha256', $key, true), 0, 16);
// Use defuse/php-encryption if possible.
if (!$force_compat && version_compare(\PHP_VERSION, '5.4.0', '>=') && function_exists('openssl_encrypt'))
{
try
{
return base64_encode(\Crypto::Encrypt($plaintext, $key));
}
catch (\Exception $e)
{
return false;
}
}
// Otherwise, use the CryptoCompat class.
return base64_encode(\CryptoCompat::encrypt($plaintext, $key));
}
/**
* Decrypt a string using AES.
*
* @param string $plaintext
* @param string $key (optional)
* @param bool $force_compat (optional)
* @return string|false
*/
public static function decrypt($ciphertext, $key = null, $force_compat = false)
{
// Get the encryption key.
$key = $key ?: config('crypto.encryption_key');
$key = substr(hash('sha256', $key, true), 0, 16);
// Check whether the ciphertext is valid.
$ciphertext = @base64_decode($ciphertext);
if (strlen($ciphertext) < 48)
{
return false;
}
// Use defuse/php-encryption if possible.
if (!$force_compat && version_compare(\PHP_VERSION, '5.4.0', '>=') && function_exists('openssl_decrypt'))
{
try
{
return \Crypto::Decrypt($ciphertext, $key);
}
catch (\Exception $e)
{
return false;
}
}
// Otherwise, use the CryptoCompat class.
return \CryptoCompat::decrypt($ciphertext, $key);
}
/**
* Generate a cryptographically secure random string.
*
* @param int $length
* @param string $format
* @return string
*/
public function getRandom($length = 32, $format = 'alnum')
{
// Find out how many bytes of entropy we really need.
switch($format)
{
case 'binary':
$entropy_required_bytes = $length;
break;
case 'hex':
$entropy_required_bytes = ceil($length / 2);
break;
case 'alnum':
case 'printable':
default:
$entropy_required_bytes = ceil($length * 3 / 4);
break;
}
// Cap entropy to 256 bits from any one source, because anything more is meaningless.
$entropy_capped_bytes = min(32, $entropy_required_bytes);
// Find and use the most secure way to generate a random string.
$entropy = false;
$is_windows = (defined('\PHP_OS') && strtoupper(substr(\PHP_OS, 0, 3)) === 'WIN');
if(function_exists('random_bytes')) // PHP 7
{
$entropy = random_bytes($entropy_capped_bytes);
}
elseif(function_exists('openssl_random_pseudo_bytes') && (!$is_windows || version_compare(\PHP_VERSION, '5.4', '>=')))
{
$entropy = openssl_random_pseudo_bytes($entropy_capped_bytes);
}
elseif(function_exists('mcrypt_create_iv') && (!$is_windows || version_compare(\PHP_VERSION, '5.3.7', '>=')))
{
$entropy = mcrypt_create_iv($entropy_capped_bytes, \MCRYPT_DEV_URANDOM);
}
elseif(function_exists('mcrypt_create_iv') && $is_windows)
{
$entropy = mcrypt_create_iv($entropy_capped_bytes, \MCRYPT_RAND);
}
elseif(!$is_windows && @is_readable('/dev/urandom'))
{
$fp = fopen('/dev/urandom', 'rb');
if (function_exists('stream_set_read_buffer')) // This function does not exist in HHVM.
{
stream_set_read_buffer($fp, 0); // Prevent reading several KB of unnecessary data from urandom.
}
$entropy = fread($fp, $entropy_capped_bytes);
fclose($fp);
}
// Use built-in source of entropy if an error occurs while using other functions.
if($entropy === false || strlen($entropy) < $entropy_capped_bytes)
{
$entropy = '';
for($i = 0; $i < $entropy_capped_bytes; $i += 2)
{
$entropy .= pack('S', rand(0, 65536) ^ mt_rand(0, 65535));
}
}
// Mixing (see RFC 4086 section 5)
$output = '';
for($i = 0; $i < $entropy_required_bytes; $i += 32)
{
$output .= hash('sha256', $entropy . $i . rand(), true);
}
// Encode and return the random string.
switch($format)
{
case 'binary':
return substr($output, 0, $length);
case 'printable':
$salt = '';
for($i = 0; $i < $length; $i++)
{
$salt .= chr(33 + (crc32(sha1($i . $output)) % 94));
}
return $salt;
case 'hex':
return substr(bin2hex($output), 0, $length);
case 'alnum':
default:
$salt = substr(base64_encode($output), 0, $length);
$replacements = chr(rand(65, 90)) . chr(rand(97, 122)) . rand(0, 9);
return strtr($salt, '+/=', $replacements);
}
}
/**
* Generate a cryptographically secure random number between $min and $max.
*
* @param int $min
* @param int $max
* @return int
*/
public static function getRandomNumber($min = 0, $max = 0x7fffffff)
{
if (function_exists('random_int'))
{
return random_int($min, $max);
}
else
{
$bytes_required = min(4, ceil(log($max - $min, 2) / 8) + 1);
$bytes = self::getRandom($bytes_required, 'binary');
$offset = abs(hexdec(bin2hex($bytes)) % ($max - $min + 1));
return intval($min + $offset);
}
}
/**
* Generate a random UUID.
*
* @return string
*/
public static function getRandomUUID()
{
$randpool = self::getRandom(16, 'binary');
$randpool[6] = chr(ord($randpool[6]) & 0x0f | 0x40);
$randpool[8] = chr(ord($randpool[8]) & 0x3f | 0x80);
return vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($randpool), 4));
}
/**
* Compare two strings in constant time.
*
* @param string $a
* @param string $b
* @return bool
*/
public static function compareStrings($a, $b)
{
$diff = strlen($a) ^ strlen($b);
$maxlen = min(strlen($a), strlen($b));
for($i = 0; $i < $maxlen; $i++)
{
$diff |= ord($a[$i]) ^ ord($b[$i]);
}
return $diff === 0;
}
/**
* Check if the current request seems to be a CSRF attack.
*
* This method returns true if the request seems to be innocent,
* and false if it seems to be a CSRF attack.
*
* @param string $referer (optional)
* @return bool
*/
public static function checkCSRF($referer = null)
{
if ($_SERVER['REQUEST_METHOD'] !== 'POST')
{
return false;
}
if (!$referer)
{
$referer = strval($_SERVER['HTTP_REFERER']);
if ($referer === '')
{
return true;
}
}
return URL::isInternalURL($referer);
}
/**
* Check if the current request seems to be an XEE attack.
*
* This method returns true if the request seems to be innocent,
* and false if it seems to be an XEE attack.
* This is the opposite of XE's Security::detectXEE() method.
*
* @param string $xml (optional)
* @return bool
*/
public static function checkXEE($xml = null)
{
// Stop if there is no XML content.
if (!$xml)
{
return true;
}
// Reject entity tags.
if (strpos($xml, '<!ENTITY') !== false)
{
return false;
}
// Check if there is no content after the xml tag.
$header = preg_replace('/<\?xml.*?\?'.'>/s', '', substr($xml, 0, 100), 1);
if (($xml = trim(substr_replace($xml, $header, 0, 100))) === '')
{
return false;
}
// Check if there is no content after the DTD.
$header = preg_replace('/^<!DOCTYPE[^>]*+>/i', '', substr($xml, 0, 200), 1);
if (($xml = trim(substr_replace($xml, $header, 0, 200))) === '')
{
return false;
}
// Check that the root tag is valid.
if (!preg_match('/^<(methodCall|methodResponse|fault)/', $xml))
{
return false;
}
return true;
}
}