(auth) add RFC 6238 (TOTP) authenticator for https://github.com/opnsense/core/issues/449

(cherry picked from commit 109fb513)
(cherry picked from commit 91cfcac9)
(cherry picked from commit a35b1453)
(cherry picked from commit e02b08ba)
(cherry picked from commit ba0c2565)
(cherry picked from commit ac181f51)
(cherry picked from commit 937a0b9c)
(cherry picked from commit 08d84231)

src/opnsense/contrib/Base32.php

+<?php
+/**
+ * Copyright (c) 2013-2014 Christian Riesen
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is furnished
+ * to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+*/
+
+namespace Base32;
+
+/**
+ * Base32 encoder and decoder
+ *
+ * Last update: 2012-06-20
+ *
+ * RFC 4648 compliant
+ * @link http://www.ietf.org/rfc/rfc4648.txt
+ *
+ * Some groundwork based on this class
+ * https://github.com/NTICompass/PHP-Base32
+ *
+ * @author Christian Riesen <chris.riesen@gmail.com>
+ * @link http://christianriesen.com
+ * @license MIT License see LICENSE file
+ */
+class Base32
+{
+    /**
+     * Alphabet for encoding and decoding base32
+     *
+     * @var array
+     */
+    private static $alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567=';
+
+    /**
+     * Creates an array from a binary string into a given chunk size
+     *
+     * @param string $binaryString String to chunk
+     * @param integer $bits Number of bits per chunk
+     * @return array
+     */
+    private static function chunk($binaryString, $bits)
+    {
+        $binaryString = chunk_split($binaryString, $bits, ' ');
+
+        if (substr($binaryString, (strlen($binaryString)) - 1)  == ' ') {
+            $binaryString = substr($binaryString, 0, strlen($binaryString)-1);
+        }
+
+        return explode(' ', $binaryString);
+    }
+
+    /**
+     * Encodes into base32
+     *
+     * @param string $string Clear text string
+     * @return string Base32 encoded string
+     */
+    public static function encode($string)
+    {
+        if (strlen($string) == 0) {
+            // Gives an empty string
+
+            return '';
+        }
+
+        // Convert string to binary
+        $binaryString = '';
+
+        foreach (str_split($string) as $s) {
+            // Return each character as an 8-bit binary string
+            $binaryString .= sprintf('%08b', ord($s));
+        }
+
+        // Break into 5-bit chunks, then break that into an array
+        $binaryArray = self::chunk($binaryString, 5);
+
+        // Pad array to be divisible by 8
+        while (count($binaryArray) % 8 !== 0) {
+            $binaryArray[] = null;
+        }
+
+        $base32String = '';
+
+        // Encode in base32
+        foreach ($binaryArray as $bin) {
+            $char = 32;
+
+            if (!is_null($bin)) {
+                // Pad the binary strings
+                $bin = str_pad($bin, 5, 0, STR_PAD_RIGHT);
+                $char = bindec($bin);
+            }
+
+            // Base32 character
+            $base32String .= self::$alphabet[$char];
+        }
+
+        return $base32String;
+    }
+
+    /**
+     * Decodes base32
+     *
+     * @param string $base32String Base32 encoded string
+     * @return string Clear text string
+     */
+    public static function decode($base32String)
+    {
+        // Only work in upper cases
+        $base32String = strtoupper($base32String);
+
+        // Remove anything that is not base32 alphabet
+        $pattern = '/[^A-Z2-7]/';
+
+        $base32String = preg_replace($pattern, '', $base32String);
+
+        if (strlen($base32String) == 0) {
+            // Gives an empty string
+            return '';
+        }
+
+        $base32Array = str_split($base32String);
+
+        $string = '';
+
+        foreach ($base32Array as $str) {
+            $char = strpos(self::$alphabet, $str);
+
+            // Ignore the padding character
+            if ($char !== 32) {
+                $string .= sprintf('%05b', $char);
+            }
+        }
+
+        while (strlen($string) %8 !== 0) {
+            $string = substr($string, 0, strlen($string)-1);
+        }
+
+        $binaryArray = self::chunk($string, 8);
+
+        $realString = '';
+
+        foreach ($binaryArray as $bin) {
+            // Pad each value to 8 bits
+            $bin = str_pad($bin, 8, 0, STR_PAD_RIGHT);
+            // Convert binary strings to ASCII
+            $realString .= chr(bindec($bin));
+        }
+
+        return $realString;
+    }
+}

src/opnsense/mvc/app/library/OPNsense/Auth/AuthenticationFactory.php

@@ -110,6 +110,9 @@ class AuthenticationFactory
                 case 'api':
                     $authObject = new API();
                     break;
+                case 'totp':
+                    $authObject = new LocalTOTP();
+                    break;
                 default:
                     $authObject = null;
             }

src/opnsense/mvc/app/library/OPNsense/Auth/Local.php

@@ -56,12 +56,11 @@ class Local implements IAuthConnector
     }
 
     /**
-     * authenticate user against local database (in config.xml)
-     * @param string $username username to authenticate
-     * @param string $password user password
-     * @return bool authentication status
+     * find user settings in local database
+     * @param string $username username to find
+     * @return SimpleXMLElement|null user settings (xml section)
      */
-    public function authenticate($username, $password)
+    protected function getUser($username)
     {
         // search local user in database
         $configObj = Config::getInstance()->object();
@@ -73,7 +72,24 @@ class Local implements IAuthConnector
                 break;
             }
         }
+        return $userObject;
+    }
 
+    /**
+     * authenticate user against local database (in config.xml)
+     * @param string|SimpleXMLElement $username username (or xml object) to authenticate
+     * @param string $password user password
+     * @return bool authentication status
+     */
+    public function authenticate($username, $password)
+    {
+        if (is_a($username, 'SimpleXMLElement')) {
+            // user xml section provided
+            $userObject = $username;
+        } else {
+            // get xml section from config
+            $userObject = $this->getUser($username);
+        }
         if ($userObject != null) {
             if (isset($userObject->disabled)) {
                 // disabled user

src/opnsense/mvc/app/library/OPNsense/Auth/LocalTOTP.php

+<?php
+/**
+ *    Copyright (C) 2015 Deciso B.V.
+ *
+ *    All rights reserved.
+ *
+ *    Redistribution and use in source and binary forms, with or without
+ *    modification, are permitted provided that the following conditions are met:
+ *
+ *    1. Redistributions of source code must retain the above copyright notice,
+ *       this list of conditions and the following disclaimer.
+ *
+ *    2. Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *
+ *    THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ *    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+ *    AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ *    AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+ *    OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ *    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ *    INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ *    CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ *    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ *    POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+namespace OPNsense\Auth;
+
+require_once("Base32.php");
+
+/**
+ * RFC 6238 TOTP: Time-Based One-Time Password Authenticator
+ * @package OPNsense\Auth
+ */
+class LocalTOTP extends Local
+{
+    /**
+     * @var int time window in seconds (google auth uses 30, some hardware tokens use 60)
+     */
+    private $timeWindow = 30;
+
+    /**
+     * @var int key length (6,8)
+     */
+    private $otpLength = 6;
+
+    /**
+     * @var int number of seconds the clocks (local, remote) may differ
+     */
+    private $graceperiod = 10;
+
+    /**
+     * set connector properties
+     * @param array $config connection properties
+     */
+    public function setProperties($config)
+    {
+        parent::setProperties($config);
+        if (!empty($config['timeWindow'])) {
+            $this->timeWindow = $config['timeWindow'];
+        }
+        if (!empty($config['otpLength'])) {
+            $this->otpLength = $config['otpLength'];
+        }
+        if (!empty($config['graceperiod'])) {
+            $this->graceperiod = $config['graceperiod'];
+        }
+    }
+
+    /**
+     * use graceperiod and timeWindow to calculate which moments in time we should check
+     * @return array timestamps
+     */
+    private function timesToCheck()
+    {
+        $result = array();
+        if ($this->graceperiod > $this->timeWindow) {
+            $step = $this->timeWindow;
+            $start = -1 * floor($this->graceperiod  / $this->timeWindow) * $this->timeWindow;
+        } else {
+            $step = $this->graceperiod;
+            $start = -1 * $this->graceperiod;
+        }
+        $now = time();
+        for ($count = $start ; $count <= $this->graceperiod ; $count += $step) {
+            $result[] = $now + $count;
+            if ($this->graceperiod == 0) {
+                // special case, we expect the clocks to match 100%, so step and target are both 0
+                break;
+            }
+        }
+        return $result;
+    }
+
+    /**
+     * @param int $moment timestemp
+     * @param string $secret secret to use
+     * @return calculated token code
+     */
+    private function calculateToken($moment, $secret)
+    {
+        // calculate binary 8 character time for provided window
+        $binary_time = pack("N", (int)($moment/$this->timeWindow));
+        $binary_time = str_pad($binary_time,8, chr(0), STR_PAD_LEFT);
+
+        // Generate the hash using the SHA1 algorithm
+        $hash = hash_hmac ('sha1', $binary_time, $secret, true);
+        $offset = ord($hash[19]) & 0xf;
+        $otp = (
+                ((ord($hash[$offset+0]) & 0x7f) << 24 ) |
+                ((ord($hash[$offset+1]) & 0xff) << 16 ) |
+                ((ord($hash[$offset+2]) & 0xff) << 8 ) |
+                (ord($hash[$offset+3]) & 0xff)
+            ) % pow(10, $this->otpLength);
+
+
+        $otp = str_pad($otp, $this->otpLength, "0", STR_PAD_LEFT);
+        return $otp;
+    }
+
+    /**
+     * return current token code
+     * @param $base32seed secret to use
+     * @return string token code
+     */
+    public function testToken($base32seed)
+    {
+        $otp_seed = \Base32\Base32::decode($base32seed);
+        return $this->calculateToken(time(), $otp_seed);
+    }
+
+    /**
+     * authenticate TOTP RFC 6238
+     * @param string $secret secret seed to use
+     * @param string $code provided code
+     * @return bool is valid
+     */
+    private function authTOTP($secret, $code)
+    {
+        foreach ($this->timesToCheck() as $moment) {
+            if ($code == $this->calculateToken($moment, $secret)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * authenticate user against otp key stored in local database
+     * @param string $username username to authenticate
+     * @param string $password user password
+     * @return bool authentication status
+     */
+    public function authenticate($username, $password)
+    {
+        $userObject = $this->getUser($username);
+        if ($userObject != null && !empty($userObject->otp_seed)) {
+            if (strlen($password) > $this->otpLength) {
+                // split otp token code and userpassword
+                $code = substr($password, 0, $this->otpLength);
+                $userPassword =  substr($password, $this->otpLength);
+                $otp_seed = \Base32\Base32::decode($userObject->otp_seed);
+                if ($this->authTOTP($otp_seed, $code)) {
+                    // token valid, do local auth
+                    return parent::authenticate($userObject, $userPassword);
+                }
+            }
+        }
+        return false;
+    }
+}

src/www/system_authservers.php

@@ -32,9 +32,10 @@ require_once("auth.inc");
 
 
 $auth_server_types = array(
-    'ldap' => "LDAP",
-    'radius' => "Radius",
-    'voucher' => "Voucher"
+    'ldap' => gettext("LDAP"),
+    'radius' => gettext("Radius"),
+    'voucher' => gettext("Voucher"),
+    'totp' => gettext("Local + Timebased One Time Password")
 );
 
 
@@ -110,9 +111,11 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
             $pconfig['simplePasswords'] = $a_server[$id]['simplePasswords'];
             $pconfig['usernameLength'] = $a_server[$id]['usernameLength'];
             $pconfig['passwordLength'] = $a_server[$id]['passwordLength'];
+        } elseif ($pconfig['type'] == 'totp') {
+            $pconfig['graceperiod'] = $a_server[$id]['graceperiod'];
+            $pconfig['timeWindow'] = $a_server[$id]['timeWindow'];
         }
     }
-
 } elseif ($_SERVER['REQUEST_METHOD'] === 'POST') {
     $input_errors = array();
     $pconfig = $_POST;
@@ -252,6 +255,9 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
               $server['simplePasswords'] = !empty($pconfig['simplePasswords']);
               $server['usernameLength'] = $pconfig['usernameLength'];
               $server['passwordLength'] = $pconfig['passwordLength'];
+          } elseif ($server['type'] == 'totp') {
+              $server['timeWindow'] = filter_var($pconfig['timeWindow'], FILTER_SANITIZE_NUMBER_INT);
+              $server['graceperiod'] = filter_var($pconfig['graceperiod'], FILTER_SANITIZE_NUMBER_INT);
           }
 
           if (isset($id) && isset($config['system']['authserver'][$id])) {
@@ -347,12 +353,15 @@ $( document ).ready(function() {
         $(".auth_radius").addClass('hidden');
         $(".auth_ldap").addClass('hidden');
         $(".auth_voucher").addClass('hidden');
+        $(".auth_totp").addClass('hidden');
         if ($("#type").val() == 'ldap') {
             $(".auth_ldap").removeClass('hidden');
         } else if ($("#type").val() == 'radius') {
             $(".auth_radius").removeClass('hidden');
         } else if ($("#type").val() == 'voucher') {
           $(".auth_voucher").removeClass('hidden');
+      } else if ($("#type").val() == 'totp') {
+          $(".auth_totp").removeClass('hidden');
         }
     });
 
@@ -695,6 +704,37 @@ endif; ?>
                     </div>
                   </td>
                 </tr>
+                <!-- TOTP -->
+                <tr class="auth_totp hidden">
+                  <td><a id="help_for_totp_otpLength" href="#" class="showhelp"><i class="fa fa-info-circle"></i></a> <?=gettext("Token length");?></td>
+                  <td>
+                    <select name="otpLength" class="selectpicker" data-style="btn-default">
+                      <option value="6" <?=empty($pconfig['otpLength']) || $pconfig['otpLength'] == "6" ? "selected=\"selected\"" : "";?> >6</option>
+                      <option value="8" <?=!empty($pconfig['otpLength']) && $pconfig['otpLength'] == "8" ? "selected=\"selected\"" : "";?> >8</option>
+                    </select>
+                    <div class="hidden" for="help_for_totp_otpLength">
+                      <?= gettext("Token length to use") ?>
+                    </div>
+                  </td>
+                </tr>
+                <tr class="auth_totp hidden">
+                  <td><a id="help_for_totp_timeWindow" href="#" class="showhelp"><i class="fa fa-info-circle"></i></a> <?=gettext("Time window");?></td>
+                  <td>
+                    <input name="timeWindow" type="text" value="<?=$pconfig['timeWindow'];?>"/>
+                    <div class="hidden" for="help_for_totp_timeWindow">
+                      <?= gettext("The time period in which the token will be valid, default is 30 seconds (google authenticator)") ?>
+                    </div>
+                  </td>
+                </tr>
+                <tr class="auth_totp hidden">
+                  <td><a id="help_for_totp_graceperiod" href="#" class="showhelp"><i class="fa fa-info-circle"></i></a> <?=gettext("Grace period");?></td>
+                  <td>
+                    <input name="graceperiod" type="text" value="<?=$pconfig['graceperiod'];?>"/>
+                    <div class="hidden" for="help_for_totp_graceperiod">
+                      <?= gettext("Time in seconds in which this server and the token may differ, default is 10 seconds. Set higher for a less secure easier match.") ?>
+                    </div>
+                  </td>
+                </tr>
                 <tr>
                   <td>&nbsp;</td>
                   <td>

src/www/system_usermanager.php

@@ -29,6 +29,7 @@
     POSSIBILITY OF SUCH DAMAGE.
 */
 require_once("guiconfig.inc");
+require_once("Base32.php");
 
 function get_user_privdesc(& $user)
 {
@@ -120,7 +121,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
         exit;
     } elseif ($act == 'new' || $act == 'edit') {
         // edit user, load or init data
-        $fieldnames = array('user_dn', 'descr', 'expires', 'scope', 'uid', 'priv', 'ipsecpsk', 'lifetime');
+        $fieldnames = array('user_dn', 'descr', 'expires', 'scope', 'uid', 'priv', 'ipsecpsk', 'lifetime', 'otp_seed');
         if (isset($id)) {
             if (isset($a_user[$id]['authorizedkeys'])) {
                 $pconfig['authorizedkeys'] = base64_decode($a_user[$id]['authorizedkeys']);
@@ -332,6 +333,12 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
             $userent['expires'] = $pconfig['expires'];
             $userent['authorizedkeys'] = base64_encode($pconfig['authorizedkeys']);
             $userent['ipsecpsk'] = $pconfig['ipsecpsk'];
+            if (!empty($pconfig['gen_otp_seed'])) {
+                // generate 160bit base32 encoded secret
+                $userent['otp_seed'] = Base32\Base32::encode(openssl_random_pseudo_bytes(20));
+            } else {
+                $userent['otp_seed'] = trim($pconfig['otp_seed']);
+            }
 
             if (!empty($pconfig['disabled'])) {
                 $userent['disabled'] = true;
@@ -898,6 +905,28 @@ $( document ).ready(function() {
                   </tr>
 <?php
                 endif;?>
+                  <tr>
+                    <td><a id="help_for_otp_seed" href="#" class="showhelp"><i class="fa fa-info-circle"></i></a>  <?=gettext("OTP seed");?></td>
+                    <td>
+                      <input name="otp_seed" type="text" value="<?=$pconfig['otp_seed'];?>"/>
+                      <input type="checkbox" name="gen_otp_seed"/>&nbsp;<small><?=gettext("generate new (160bit) secret");?></small>
+                      <div class="hidden" for="help_for_otp_seed">
+                        <?=gettext("OTP (base32) seed to use when a one time password authenticator is used");?><br/>
+<?php
+                        if (!empty($pconfig['otp_seed'])):
+                            // construct google url, using token, username and this machines hostname
+                            $google_otp_url = "https://www.google.com/chart?chs=200x200&amp;chld=M|0&amp;cht=qr&amp;chl=otpauth://totp/";
+                            $google_otp_url .= $pconfig['usernamefld']."@".htmlspecialchars($config['system']['hostname'])."%3Fsecret%3D";
+                            $google_otp_url .= $pconfig['otp_seed'];
+                        ?>
+                            <br/>
+                            <?=gettext("When using google authenticator, the following link provides a qrcode for easy setup");?><br/>
+                            <a href="<?=$google_otp_url;?>" target="_blank"><?=$google_otp_url;?></a>
+<?php
+                        endif;?>
+                      </div>
+                    </td>
+                  </tr>
                   <tr>
                     <td><i class="fa fa-info-circle text-muted"></i> <?=gettext("Authorized keys");?></td>
                     <td>