WB 2.08.x

<?php

/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */

/**

 * SecureTokens.php

 *

 * @category      Core

 * @package       Core_Security

 * @subpackage    WB-2.8.4 and up

 * @copyright     Manuela v.d.Decken <manuela@isteam.de>

 * @author        Manuela v.d.Decken <manuela@isteam.de>

 * @license       http://www.gnu.org/licenses/gpl.html   GPL License

 * @

 * @version       0.1.2

 * @revision      $Revision: $

 * @link          $HeadURL: $

 * @lastmodified $Date: $

 * @since         File available since 12.09.2015

 * @description

 * This class is a replacement for the former class SecureForm using the SecureTokensInterface

 *

 * Settings for this class

 * TYPE    KONSTANTE             REGISTY-VAR                  DEFAULTWERT

 * boolean SEC_TOKEN_FINGERPRINT ($oReg->SecTokenFingerprint) [default=true]

 * integer SEC_TOKEN_NETMASK4    ($oReg->SecTokenNetmask4)    0-255 [default=24]

 * integer SEC_TOKEN_NETMASK6    ($oReg->SecTokenNetmask6)    0-128 [default=64]

 * integer SEC_TOKEN_LIFE_TIME   ($oReg->SecTokenLifeTime)    1800 | 2700 | 3600[default] | 7200

*/

class SecureTokens

{

/** character string for 64char encoding */

    const CHAR64 = 'Zabcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZa';

/** possible settings for TokenLifeTime in seconds */

    const LIFETIMES = [1800, 2700, 3600, 7200];  // seconds for 30min / 45min / 1h / 2h

/** lifetime in seconds to use in DEBUG mode if negative value is given (-1) */

    const DEBUG_LIFETIME = 300;

/** array to hold all tokens from the session */

    private $aTokens = array(

        'default' => array('value' => 0, 'expire' => 0)

    );

/** the salt for this run */

    private $sSalt            = '';

/** fingerprint of the current connection */

    private $sFingerprint     = '';

/** the FTAN token which is valid for this run */

    private $aLastCreatedFtan = null;

/* --- settings for SecureTokens ------------------------------------------------------ */

/** use fingerprinting to encode */

    private $bUseFingerprint = true;

/** maximum lifetime of a token in seconds */

    private $iTokenLifeTime   = 1800; // 30min / 45min / 1h / 2h (default = 30min)

/** bit length of the IPv4 Netmask (0-32 // 0 = off  default = 24) */

    private $iNetmaskLengthV4 = 0;

/** bit length of the IPv6 Netmask (0-128 // 0 = off  default = 64) */

    private $iNetmaskLengthV6 = 0;

/**

 * constructor

 * @param (void)

 */

    protected function __construct() {

    // load settings if available

        $this->getSettings();

    // load array of tokens from session

        $this->loadTokens();

    // at first of all remove expired tokens

        $this->removeExpiredTokens();

    // generate salt for calculations in this run

        $this->sSalt        = $this->generateSalt();

    // generate fingerprint for the current connection

        $this->sFingerprint = $this->buildFingerprint();

    }

/**

 * @param (void)

 * @return integer

 */

    public function getTokenLifeTime()

    {

        // return 5 seconds less then lifetime to compensate delay of transfer to the client

        return $this->iTokenLifeTime - 5;

    }

/**

 * Dummy method for backward compatibility

 * @return void

 * @deprecated from WB-2.8.3-SP5

 */

    final public function createFTAN() { ; } // do nothing

/**

 * Dummy method for backward compatibility

 * @return void

 * @deprecated from WB-2.8.3-SP5

 */

    final public function clearIDKEY() { ; } // do nothing

/**

 * returns the current FTAN

 * @param bool $mode: true or POST returns a complete prepared, hidden HTML-Input-Tag (default)

 *                     false or GET returns an GET argument 'key=value'

 * @return mixed:     array or string

 * @deprecated the param $mMode is set deprecated

 *              string retvals are set deprecated. From versions after 2.8.4 retval will be array only

 */

    final public function getFTAN($mMode = 'POST')

    {

        if (is_null($this->aLastCreatedFtan)) {

            $sFtan = md5($this->sSalt);

            $this->aLastCreatedFtan = $this->addToken(

                substr($sFtan, rand(0,15), 16),

                substr($sFtan, rand(0,15), 16)

            );

        }

        $aFtan = $this->aTokens[$this->aLastCreatedFtan];

        $aFtan['name']  = $this->aLastCreatedFtan;

        $aFtan['value'] = $this->encode64(md5($aFtan['value'].$this->sFingerprint));

        if (is_string($mMode)) {

            $mMode = strtoupper($mMode);

        } else {

            $mMode = $mMode === true ? 'POST' : 'GET';

        }

        switch ($mMode):

            case 'POST':

                return '<input type="hidden" name="'.$aFtan['name'].'" value="'

                      .$aFtan['value'].'" title="">';

                break;

            case 'GET':

                return $aFtan['name'].'='.$aFtan['value'];

                break;

            default:

                return array('name' => $aFtan['name'], 'value' => $aFtan['value']);

        endswitch;

    }

/**

 * checks received form-transactionnumbers against session-stored one

 * @param string $mode: requestmethode POST(default) or GET

 * @return bool:    true if numbers matches against stored ones

 *

 * requirements: an active session must be available

 * this check will prevent from multiple sending a form. history.back() also will never work

 */

    final public function checkFTAN($mMode = 'POST')

    {

        $bRetval = false;

        // get the POST/GET arguments

        $aArguments = (strtoupper($mMode) == 'POST' ? $_POST : $_GET);

        // encode the value of all matching tokens

        $aMatchingTokens = array_map(

            function ($aToken) {

                return $this->encode64(md5($aToken['value'].$this->sFingerprint));

            },

            // extract all matching tokens from $this->aTokens

            array_intersect_key($this->aTokens, $aArguments)

        );

        // extract all matching arguments from $aArguments

        $aMatchingArguments = array_intersect_key($aArguments, $this->aTokens);

        // get all tokens with matching values from match lists

        $aHits = array_intersect($aMatchingTokens, $aMatchingArguments);

        foreach ($aHits as $sTokenName => $sValue) {

            $bRetval = true;

            $this->removeToken($sTokenName);

        }

        return $bRetval;

    }

/**

 * store value in session and returns an accesskey to it

 * @param mixed $mValue can be numeric, string or array

 * @return string

 */

    final public function getIDKEY($mValue)

    {

        if (is_array($mValue) == true) {

            // serialize value, if it's an array

            $mValue = serialize($mValue);

        }

        // crypt value with salt into md5-hash and return a 16-digit block from random start position

        $sTokenName = $this->addToken(

            substr(md5($this->sSalt.(string)$mValue), rand(0,15), 16),

            $mValue

        );

        return $sTokenName;

    }

/*

 * search for key in session and returns the original value

 * @param string $sFieldname: name of the POST/GET-Field containing the key or hex-key itself

 * @param mixed $mDefault: returnvalue if key not exist (default 0)

 * @param string $sRequest: requestmethode can be POST or GET or '' (default POST)

 * @return mixed: the original value (string, numeric, array) or DEFAULT if request fails

 * @description: each IDKEY can be checked only once. Unused Keys stay in list until they expire

 */

    final public function checkIDKEY( $sFieldname, $mDefault = 0, $sRequest = 'POST' )

    {

        $mReturnValue = $mDefault; // set returnvalue to default

        $sRequest = strtoupper($sRequest);

        switch ($sRequest) {

            case 'POST':

            case 'GET':

                $sTokenName = @$GLOBALS['_'.$sRequest][$sFieldname] ?: $sFieldname;

                break;

            default:

                $sTokenName = $sFieldname;

        }

        if (preg_match('/[0-9a-f]{16}$/i', $sTokenName)) {

        // key must be a 16-digit hexvalue

            if (array_key_exists($sTokenName, $this->aTokens)) {

            // check if key is stored in IDKEYs-list

                $mReturnValue = $this->aTokens[$sTokenName]['value']; // get stored value

                $this->removeToken($sTokenName);   // remove from list to prevent multiuse

                if (preg_match('/.*(?<!\{).*(\d:\{.*;\}).*(?!\}).*/', $mReturnValue)) {

                // if value is a serialized array, then deserialize it

                    $mReturnValue = unserialize($mReturnValue);

                }

            }

        }

        return $mReturnValue;

    }

// *** from here private methods only ****************************************************

/**

 * load all tokens from session

 */

    private function loadTokens()

    {

        if (isset($_SESSION['TOKENS'])) {

            $this->aTokens = unserialize($_SESSION['TOKENS']);

        } else {

            $this->saveTokens();

        }

    }

/**

 * save all tokens into session

 */

    private function saveTokens()

    {

        $_SESSION['TOKENS'] = serialize($this->aTokens);

    }

/**

 * add new token to the list

 * @param string $sTokenName

 * @param string $sValue

 * @return string  name(index) of the token

 */

    private function addToken($sTokenName, $sValue)

    {

        $sTokenName = substr($sTokenName, 0, 16);

        $sTokenName[0] = dechex(10 + (hexdec($sTokenName[0]) % 5));

        while (isset($this->aTokens[$sTokenName])) {

            $sTokenName = sprintf('%16x', hexdec($sTokenName)+1);

        }

        $this->aTokens[$sTokenName] = array(

            'value'  => $sValue,

            'expire' => time()+$this->iTokenLifeTime

        );

        $this->saveTokens();

        return $sTokenName;

    }

/**

 * remove the token, called sTokenName from list

 * @param type $sTokenName

 */

    private function removeToken($sTokenName)

    {

        if (isset($this->aTokens[$sTokenName])) {

            unset($this->aTokens[$sTokenName]);

        }

        $this->saveTokens();

    }

/**

 * remove all expired tokens from list

 */

    private function removeExpiredTokens()

    {

        $iTimestamp = time();

        foreach ($this->aTokens as $sTokenName => $aToken) {

            if ($aToken['expire'] <= $iTimestamp && $aToken['expire'] != 0){

                unset($this->aTokens[$sTokenName]);

            }

        }

        $this->saveTokens();

    }

/**

 * generate a runtime depended hash

 * @return string  md5 hash

 */

    private function generateSalt()

    {

        list($fUsec, $fSec) = explode(" ", microtime());

        $sSalt = (string)rand(10000, 99999)

               . (string)((float)$fUsec + (float)$fSec)

               . (string)rand(10000, 99999);

        return md5($sSalt);

    }

/**

 * build a simple fingerprint

 * @return string

 */

    private function buildFingerprint()

    {

        if (!$this->bUseFingerprint) { return md5('dummy'); }

        $sClientIp = isset($_SERVER['REMOTE_ADDR']) ? $_SERVER['REMOTE_ADDR'] : '0.0.0.0';

        $sFingerprint = __FILE__.PHP_VERSION

                      . isset($_SERVER['SERVER_SIGNATURE']) ? $_SERVER['SERVER_SIGNATURE'] : 'unknown'

                      . isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : 'AGENT'

                      . $this->calcClientIpHash($sClientIp);

        return md5($sFingerprint);

    }

/**

 * mask IPv4 as well IPv6 addresses with netmask and make a md5 hash from

 * @param string $sClientIp IP as string from $_SERVER['REMOTE_ADDR']

 * @return md5 value of masked ip

 * @description this method does not accept the IPv6/IPv4 mixed format

 *               like "2222:3333:4444:5555:6666:7777:192.168.1.200"

 */

    private function calcClientIpHash($sRawIp)

    {

        if (strpos($sRawIp, ':') === false) {

        // calculate IPv4

            $iIpV4 = ip2long($sRawIp);

        // calculate netmask

            $iMask = ($this->iNetmaskLengthV4 < 1)

                ? 0

                : bindec(

                    str_repeat('1', $this->iNetmaskLengthV4).

                    str_repeat('0', 32 - $this->iNetmaskLengthV4)

                );

        // apply mask

            $sIp = long2ip($iIpV4 & $iMask);

        } else {

        // sanitize IPv6

            $iWords = 8 - count(preg_split('/:/', $sRawIp, null, PREG_SPLIT_NO_EMPTY));

            $sReplacement = $iWords ? implode(':', array_fill(0, $iWords, '0000')) : '';

            $sClientIp = trim(preg_replace('/\:\:/', ':'.$sReplacement.':', $sRawIp), ':');

            $aIpV6 = array_map(

                function($sPart) {

                    return str_pad($sPart, 4, '0', STR_PAD_LEFT);

                },

                preg_split('/:/', $sClientIp)

            );

        // calculate netmask

            $iMask = $this->iNetmaskLengthV6;

            if ($this->iNetmaskLengthV6 < 1) {

                $aMask = array_fill(0, 8, str_repeat('0', 16));

            } else {

                $aMask = str_split(

                    str_repeat('1', $this->iNetmaskLengthV6).

                    str_repeat('0', 128 - $this->iNetmaskLengthV6),

                    16

                );

            }

        // apply mask

            array_walk(

                $aIpV6,

                function(&$sWord, $iIndex) use ($aMask) {

                    $sWord = sprintf('%04x', hexdec($sWord) & bindec($aMask[$iIndex]));

                }

            );

            $sIp = implode(':', $aIpV6);

        }

        return md5($sIp); // return the hash

    }

/**

 * encode a hex string into a 64char based string

 * @param string $sMd5Hash

 * @return string

 * @description reduce the 32char length of a MD5 to 21 chars

 */

    private function encode64($sMd5Hash)

    {

        $sCharList = self::CHAR64;

        $sBin = implode(

            '',

            array_map(

                function($sPart) {

                    return sprintf('%032b', hexdec($sPart));

                },

                str_split($sMd5Hash, 8)

            )

        );

        $sResult = implode(

            '',

            array_map(

                function($sPart) use ($sCharList) {

                    $sPart = str_pad($sPart, 6, '0', STR_PAD_RIGHT);

                    return $sCharList[bindec($sPart)];

                },

                str_split($sBin, 6)

            )

        );

        return $sResult;

    }

/**

 * read settings if available

 */

    private function getSettings()

    {

        $this->bUseFingerprint  = isset($this->oReg->SecTokenFingerprint)

                                  ? $this->oReg->SecTokenFingerprint

                                  : $this->bUseFingerprint;

        $this->iNetmaskLengthV4 = isset($this->oReg->SecTokenNetmask4)

                                  ? $this->oReg->SecTokenNetmask4

                                  : $this->iNetmaskLengthV4;

        $this->iNetmaskLengthV6 = isset($this->oReg->SecTokenNetmask6)

                                  ? $this->oReg->SecTokenNetmask6

                                  : $this->iNetmaskLengthV6;

        $this->iTokenLifeTime   = isset($this->oReg->SecTokenLifeTime)

                                  ? $this->oReg->SecTokenLifeTime

                                  : $this->iTokenLifeTime;

        $this->iNetmaskLengthV4 = ($this->iNetmaskLengthV4 < 1 || $this->iNetmaskLengthV4 > 32)

                                  ? 0 :$this->iNetmaskLengthV4;

        $this->iNetmaskLengthV6 = ($this->iNetmaskLengthV6 < 1 || $this->iNetmaskLengthV6 > 128)

                                  ? 0 :$this->iNetmaskLengthV6;

        $aLifeTimes = self::LIFETIMES;

        sort($aLifeTimes);

        if ($this->iTokenLifeTime < 0 && DEBUG) {

            $this->iTokenLifeTime = self::DEBUG_LIFETIME;

        } else {

            $iRetval = array_pop($aLifeTimes);

            foreach ($aLifeTimes as $iValue) {

                if ($this->iTokenLifeTime <= $iValue) {

                    $iRetval = $iValue;

                    break;

                }

            }

            $this->iTokenLifeTime = $iRetval;

        }

    }

} // end of class SecureTokens