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* Redo #15 which somehow didn't merge...

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RobThree
2017-02-17 12:15:17 +01:00
parent b3bb9685ea
commit 178c60d947
9 changed files with 2107 additions and 114 deletions
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lib/TwoFactorAuth.php
+84 -75
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@@ -1,103 +1,78 @@
<?php
namespace RobThree\Auth;
use RobThree\Auth\Providers\Qr\IQRCodeProvider;
use RobThree\Auth\Providers\Rng\IRNGProvider;
// Based on / inspired by: https://github.com/PHPGangsta/GoogleAuthenticator
// Algorithms, digits, period etc. explained: https://github.com/google/google-authenticator/wiki/Key-Uri-Format
class TwoFactorAuth
class TwoFactorAuth
{
private $algorithm;
private $period;
private $digits;
private $issuer;
private $qrcodeprovider;
private $rngprovider;
private $qrcodeprovider = null;
private $rngprovider = null;
private static $_base32dict = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567=';
private static $_base32;
private static $_base32lookup = array();
private static $_supportedalgos = array('sha1', 'sha256', 'sha512', 'md5');
function __construct($issuer = null, $digits = 6, $period = 30, $algorithm = 'sha1', $qrcodeprovider = null, $rngprovider = null)
function __construct($issuer = null, $digits = 6, $period = 30, $algorithm = 'sha1', IQRCodeProvider $qrcodeprovider = null, IRNGProvider $rngprovider = null)
{
$this->issuer = $issuer;
if (!is_int($digits) || $digits <= 0)
throw new TwoFactorAuthException('Digits must be int > 0');
$this->digits = $digits;
if (!is_int($period) || $period <= 0)
throw new TwoFactorAuthException('Period must be int > 0');
$this->period = $period;
$algorithm = strtolower(trim($algorithm));
if (!in_array($algorithm, self::$_supportedalgos))
throw new TwoFactorAuthException('Unsupported algorithm: ' . $algorithm);
$this->algorithm = $algorithm;
// Set default QR Code provider if none was specified
if ($qrcodeprovider==null)
$qrcodeprovider = new Providers\Qr\GoogleQRCodeProvider();
if (!($qrcodeprovider instanceof Providers\Qr\IQRCodeProvider))
throw new TwoFactorAuthException('QRCodeProvider must implement IQRCodeProvider');
$this->qrcodeprovider = $qrcodeprovider;
// Try to find best available RNG provider if none was specified
if ($rngprovider==null) {
if (function_exists('random_bytes')) {
$rngprovider = new Providers\Rng\CSRNGProvider();
} elseif (function_exists('mcrypt_create_iv')) {
$rngprovider = new Providers\Rng\MCryptRNGProvider();
} elseif (function_exists('openssl_random_pseudo_bytes')) {
$rngprovider = new Providers\Rng\OpenSSLRNGProvider();
} elseif (function_exists('hash')) {
$rngprovider = new Providers\Rng\HashRNGProvider();
} else {
throw new TwoFactorAuthException('Unable to find a suited RNGProvider');
}
}
if (!($rngprovider instanceof Providers\Rng\IRNGProvider))
throw new TwoFactorAuthException('RNGProvider must implement IRNGProvider');
$this->rngprovider = $rngprovider;
self::$_base32 = str_split(self::$_base32dict);
self::$_base32lookup = array_flip(self::$_base32);
}
/**
* Create a new secret
*/
public function createSecret($bits = 80, $requirecryptosecure = true)
public function createSecret($bits = 80, $requirecryptosecure = true)
{
$secret = '';
$bytes = ceil($bits / 5); //We use 5 bits of each byte (since we have a 32-character 'alphabet' / BASE32)
if ($requirecryptosecure && !$this->rngprovider->isCryptographicallySecure())
$rngprovider = $this->getRngprovider();
if ($requirecryptosecure && !$rngprovider->isCryptographicallySecure())
throw new TwoFactorAuthException('RNG provider is not cryptographically secure');
$rnd = $this->rngprovider->getRandomBytes($bytes);
$rnd = $rngprovider->getRandomBytes($bytes);
for ($i = 0; $i < $bytes; $i++)
$secret .= self::$_base32[ord($rnd[$i]) & 31]; //Mask out left 3 bits for 0-31 values
return $secret;
}
/**
* Calculate the code with given secret and point in time
*/
public function getCode($secret, $time = null)
{
$secretkey = $this->base32Decode($secret);
$timestamp = "\0\0\0\0" . pack('N*', $this->getTimeSlice($this->getTime($time))); // Pack time into binary string
$hashhmac = hash_hmac($this->algorithm, $timestamp, $secretkey, true); // Hash it with users secret key
$hashpart = substr($hashhmac, ord(substr($hashhmac, -1)) & 0x0F, 4); // Use last nibble of result as index/offset and grab 4 bytes of the result
$value = unpack('N', $hashpart); // Unpack binary value
$value = $value[1] & 0x7FFFFFFF; // Drop MSB, keep only 31 bits
return str_pad($value % pow(10, $this->digits), $this->digits, '0', STR_PAD_LEFT);
}
/**
* Check if the code is correct. This will accept codes starting from ($discrepancy * $period) sec ago to ($discrepancy * period) sec from now
*/
@@ -105,57 +80,57 @@ class TwoFactorAuth
{
$result = false;
$timetamp = $this->getTime($time);
// To keep safe from timing-attachs we iterate *all* possible codes even though we already may have verified a code is correct
for ($i = -$discrepancy; $i <= $discrepancy; $i++)
for ($i = -$discrepancy; $i <= $discrepancy; $i++)
$result |= $this->codeEquals($this->getCode($secret, $timetamp + ($i * $this->period)), $code);
return (bool)$result;
}
/**
* Timing-attack safe comparison of 2 codes (see http://blog.ircmaxell.com/2014/11/its-all-about-time.html)
*/
private function codeEquals($safe, $user) {
if (function_exists('hash_equals')) {
return hash_equals($safe, $user);
} else {
// In general, it's not possible to prevent length leaks. So it's OK to leak the length. The important part is that
// we don't leak information about the difference of the two strings.
if (strlen($safe)===strlen($user)) {
$result = 0;
for ($i = 0; $i < strlen($safe); $i++)
$result |= (ord($safe[$i]) ^ ord($user[$i]));
return $result === 0;
}
}
// In general, it's not possible to prevent length leaks. So it's OK to leak the length. The important part is that
// we don't leak information about the difference of the two strings.
if (strlen($safe)===strlen($user)) {
$result = 0;
for ($i = 0; $i < strlen($safe); $i++)
$result |= (ord($safe[$i]) ^ ord($user[$i]));
return $result === 0;
}
return false;
}
/**
* Get data-uri of QRCode
*/
public function getQRCodeImageAsDataUri($label, $secret, $size = 200)
public function getQRCodeImageAsDataUri($label, $secret, $size = 200)
{
if (!is_int($size) || $size <= 0)
throw new TwoFactorAuthException('Size must be int > 0');
$qrcodeprovider = $this->getQrCodeProvider();
return 'data:'
. $this->qrcodeprovider->getMimeType()
. $qrcodeprovider->getMimeType()
. ';base64,'
. base64_encode($this->qrcodeprovider->getQRCodeImage($this->getQRText($label, $secret), $size));
. base64_encode($qrcodeprovider->getQRCodeImage($this->getQRText($label, $secret), $size));
}
private function getTime($time)
private function getTime($time)
{
return ($time === null) ? time() : $time;
}
private function getTimeSlice($time = null, $offset = 0)
private function getTimeSlice($time = null, $offset = 0)
{
return (int)floor($time / $this->period) + ($offset * $this->period);
}
/**
* Builds a string to be encoded in a QR code
*/
@@ -168,27 +143,61 @@ class TwoFactorAuth
. '&algorithm=' . rawurlencode(strtoupper($this->algorithm))
. '&digits=' . intval($this->digits);
}
private function base32Decode($value)
{
if (strlen($value)==0) return '';
if (preg_match('/[^'.preg_quote(self::$_base32dict).']/', $value) !== 0)
throw new TwoFactorAuthException('Invalid base32 string');
$buffer = '';
foreach (str_split($value) as $char)
foreach (str_split($value) as $char)
{
if ($char !== '=')
$buffer .= str_pad(decbin(self::$_base32lookup[$char]), 5, 0, STR_PAD_LEFT);
}
$length = strlen($buffer);
$blocks = trim(chunk_split(substr($buffer, 0, $length - ($length % 8)), 8, ' '));
$output = '';
foreach (explode(' ', $blocks) as $block)
$output .= chr(bindec(str_pad($block, 8, 0, STR_PAD_RIGHT)));
return $output;
}
}
/**
* @return IQRCodeProvider
* @throws TwoFactorAuthException
*/
public function getQrCodeProvider()
{
// Set default QR Code provider if none was specified
if (null === $this->qrcodeprovider) {
return $this->qrcodeprovider = new Providers\Qr\GoogleQRCodeProvider();
}
return $this->qrcodeprovider;
}
/**
* @return IRNGProvider
* @throws TwoFactorAuthException
*/
public function getRngprovider()
{
if (null !== $this->rngprovider) {
return $this->rngprovider;
}
if (function_exists('random_bytes')) {
return $this->rngprovider = new Providers\Rng\CSRNGProvider();
}
if (function_exists('mcrypt_create_iv')) {
return $this->rngprovider = new Providers\Rng\MCryptRNGProvider();
}
if (function_exists('openssl_random_pseudo_bytes')) {
return $this->rngprovider = new Providers\Rng\OpenSSLRNGProvider();
}
if (function_exists('hash')) {
return $this->rngprovider = new Providers\Rng\HashRNGProvider();
}
throw new TwoFactorAuthException('Unable to find a suited RNGProvider');
}
}