Commit version 1.0

GoogleAuthenticator.php

@@ -0,0 +1,208 @@
+<?php
+
+/**
+ * PHP Class for handling Google Authenticator 2-factor authentication
+ *
+ * @author Michael Kliewe
+ * @copyright 2012 Michael Kliewe
+ * @license http://www.opensource.org/licenses/bsd-license.php BSD License
+ * 
+ */
+
+class GoogleAuthenticator
+{
+    protected $_codeLength = 6;
+
+    /**
+     * Create new secret.
+     * 16 characters, randomly chosen from the allowed base32 characters.
+     *
+     * @param int $secretLength
+     * @return string
+     */
+    public function createSecret($secretLength = 16)
+    {
+        $validChars = $this->_getBase32LookupTable();
+        unset($validChars[32]);
+
+        $secret = '';
+        for ($i = 0; $i < $secretLength; $i++) {
+            $secret .= $validChars[array_rand($validChars)];
+        }
+        return $secret;
+    }
+
+    /**
+     * Calculate the code, with given secret and point in time
+     *
+     * @param string $secret
+     * @param int|null $timeSlice
+     * @return string
+     */
+    public function getCode($secret, $timeSlice = null)
+    {
+        if ($timeSlice === null) {
+            $timeSlice = floor(time() / 30);
+        }
+
+        $secretkey = $this->_base32Decode($secret);
+
+        // Pack time into binary string
+        $time = chr(0).chr(0).chr(0).chr(0).pack('N*', $timeSlice);
+        // Hash it with users secret key
+        $hm = hash_hmac('SHA1', $time, $secretkey, true);
+        // Use last nipple of result as index/offset
+        $offset = ord(substr($hm, -1)) & 0x0F;
+        // grab 4 bytes of the result
+        $hashpart = substr($hm, $offset, 4);
+
+        // Unpak binary value
+        $value = unpack('N', $hashpart);
+        $value = $value[1];
+        // Only 32 bits
+        $value = $value & 0x7FFFFFFF;
+
+        $modulo = pow(10, $this->_codeLength);
+        return str_pad($value % $modulo, $this->_codeLength, '0', STR_PAD_LEFT);
+    }
+
+    /**
+     * Get QR-Code URL for image, from google charts
+     *
+     * @param string $name
+     * @param string $secret
+     * @param string $title
+     * @return string
+     */
+    public function getQRCodeGoogleUrl($name, $secret, $title = null) {
+        $urlencoded = urlencode('otpauth://totp/'.$name.'?secret='.$secret.'');
+	if(isset($title)) {
+                $urlencoded .= urlencode('&issuer='.urlencode($title));
+        }
+        return 'https://chart.googleapis.com/chart?chs=200x200&chld=M|0&cht=qr&chl='.$urlencoded.'';
+    }
+
+    /**
+     * Check if the code is correct. This will accept codes starting from $discrepancy*30sec ago to $discrepancy*30sec from now
+     *
+     * @param string $secret
+     * @param string $code
+     * @param int $discrepancy This is the allowed time drift in 30 second units (8 means 4 minutes before or after)
+     * @param int|null $currentTimeSlice time slice if we want use other that time()
+     * @return bool
+     */
+    public function verifyCode($secret, $code, $discrepancy = 1, $currentTimeSlice = null)
+    {
+        if ($currentTimeSlice === null) {
+            $currentTimeSlice = floor(time() / 30);
+        }
+
+        for ($i = -$discrepancy; $i <= $discrepancy; $i++) {
+            $calculatedCode = $this->getCode($secret, $currentTimeSlice + $i);
+            if ($calculatedCode == $code ) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Set the code length, should be >=6
+     *
+     * @param int $length
+     * @return GoogleAuthenticator
+     */
+    public function setCodeLength($length)
+    {
+        $this->_codeLength = $length;
+        return $this;
+    }
+
+    /**
+     * Helper class to decode base32
+     *
+     * @param $secret
+     * @return bool|string
+     */
+    protected function _base32Decode($secret)
+    {
+        if (empty($secret)) return '';
+
+        $base32chars = $this->_getBase32LookupTable();
+        $base32charsFlipped = array_flip($base32chars);
+
+        $paddingCharCount = substr_count($secret, $base32chars[32]);
+        $allowedValues = array(6, 4, 3, 1, 0);
+        if (!in_array($paddingCharCount, $allowedValues)) return false;
+        for ($i = 0; $i < 4; $i++){
+            if ($paddingCharCount == $allowedValues[$i] &&
+                substr($secret, -($allowedValues[$i])) != str_repeat($base32chars[32], $allowedValues[$i])) return false;
+        }
+        $secret = str_replace('=','', $secret);
+        $secret = str_split($secret);
+        $binaryString = "";
+        for ($i = 0; $i < count($secret); $i = $i+8) {
+            $x = "";
+            if (!in_array($secret[$i], $base32chars)) return false;
+            for ($j = 0; $j < 8; $j++) {
+                $x .= str_pad(base_convert(@$base32charsFlipped[@$secret[$i + $j]], 10, 2), 5, '0', STR_PAD_LEFT);
+            }
+            $eightBits = str_split($x, 8);
+            for ($z = 0; $z < count($eightBits); $z++) {
+                $binaryString .= ( ($y = chr(base_convert($eightBits[$z], 2, 10))) || ord($y) == 48 ) ? $y:"";
+            }
+        }
+        return $binaryString;
+    }
+
+    /**
+     * Helper class to encode base32
+     *
+     * @param string $secret
+     * @param bool $padding
+     * @return string
+     */
+    protected function _base32Encode($secret, $padding = true)
+    {
+        if (empty($secret)) return '';
+
+        $base32chars = $this->_getBase32LookupTable();
+
+        $secret = str_split($secret);
+        $binaryString = "";
+        for ($i = 0; $i < count($secret); $i++) {
+            $binaryString .= str_pad(base_convert(ord($secret[$i]), 10, 2), 8, '0', STR_PAD_LEFT);
+        }
+        $fiveBitBinaryArray = str_split($binaryString, 5);
+        $base32 = "";
+        $i = 0;
+        while ($i < count($fiveBitBinaryArray)) {
+            $base32 .= $base32chars[base_convert(str_pad($fiveBitBinaryArray[$i], 5, '0'), 2, 10)];
+            $i++;
+        }
+        if ($padding && ($x = strlen($binaryString) % 40) != 0) {
+            if ($x == 8) $base32 .= str_repeat($base32chars[32], 6);
+            elseif ($x == 16) $base32 .= str_repeat($base32chars[32], 4);
+            elseif ($x == 24) $base32 .= str_repeat($base32chars[32], 3);
+            elseif ($x == 32) $base32 .= $base32chars[32];
+        }
+        return $base32;
+    }
+
+    /**
+     * Get array with all 32 characters for decoding from/encoding to base32
+     *
+     * @return array
+     */
+    protected function _getBase32LookupTable()
+    {
+        return array(
+            'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', //  7
+            'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', // 15
+            'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', // 23
+            'Y', 'Z', '2', '3', '4', '5', '6', '7', // 31
+            '='  // padding char
+        );
+    }
+}

README.md

@@ -1 +1,14 @@
-# phpmfa
+# MFA / 2FA for PHP (Using GoogleAuthenticator)
+
+Add the GoogleAuthenticator.php file in your application.
+
+Generate a secret and store this in a database with the user. This secret should be unknown to anybody and is needed for the MFA confirmation.
+
+Scan the QR code generated
+
+Confirm the MFA code using your MFA application on your phone.
+
+## Note
+For this test you have to put the code you generated into the check_mfa.php file and use a $_GET['code'] to check if the code is working or not.
+
+You should build this using a proper POST!

check_mfa.php

@@ -0,0 +1,23 @@
+<?php
+
+// Set the secret generated in generate.php, this should be fetched from a DB.
+$secret = '';
+
+// Fetching the generated MFA code from your MFA app.
+// This as a $_GET value to test it out easily, but should be a POST in production!
+echo "<p>Confirm code:</p>";
+$code = $_GET['code'];
+echo "<p>Code: $code</p>";
+
+$ga = new GoogleAuthenticator();
+// Code verify with your secret and the supplied code.
+// Discrepancy is set to '2' which is 60 seconds. Default is 1 (30 seconds) but you might be too late to input the code.
+$login = $ga->verifyCode($secret, $code, $discrepancy = 2);
+
+// If login returns TRUE
+if ($login) {
+        echo "OK";
+} else {
+        echo "FAILED";
+}
+?>

generate.php

@@ -0,0 +1,17 @@
+<?php
+require_once('GoogleAuthenticator.php');
+
+echo "<p>Create token:</p>";
+$user = 'MyLoginUsername';
+
+// Generate a new secret for the user, this secret should be stored with the user in a database or make a static setting
+$ga = new GoogleAuthenticator();
+$secret = $ga->createSecret();
+echo "<p>This personal secret should be stored in a database/user table and should never be known to anybody: $secret</p>";
+echo "<hr>"
+
+// Generate QR by using Google Charts.
+$qrCodeUrl      = $ga->getQRCodeGoogleUrl($user, $secret, 'My Environment');
+echo "<p>Scan in Google Authenticator or Microsoft Authenticator"
+echo "<img src='$qrCodeUrl'>";
+?>