class.tx_saltedpasswords_salts_phpass.php

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<?php
/***************************************************************
*  Copyright notice
*
*  (c) 2009-2011 Marcus Krause <marcus#exp2009@t3sec.info>
*  All rights reserved
*
*  This script is part of the TYPO3 project. The TYPO3 project 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 2 of the License, or
*  (at your option) any later version.
*
*  The GNU General Public License can be found at
*  http://www.gnu.org/copyleft/gpl.html.
*  A copy is found in the textfile GPL.txt and important notices to the license
*  from the author is found in LICENSE.txt distributed with these scripts.
*
*
*  This script 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.
*
*  This copyright notice MUST APPEAR in all copies of the script!
***************************************************************/
/**
 * Contains class "tx_saltedpasswords_salts_phpass"
 * that provides PHPass salted hashing.
 *
 * Derived from Drupal CMS
 * original license: GNU General Public License (GPL)
 * @see http://drupal.org/node/29706/
 *
 * Based on the Portable PHP password hashing framework
 * original license: Public Domain
 * @see http://www.openwall.com/phpass/
 *
 * $Id: class.tx_saltedpasswords_salts_phpass.php 10120 2011-01-18 20:03:36Z ohader $
 */


/**
 * Class that implements PHPass salted hashing based on Drupal's
 * modified Openwall implementation.
 *
 * PHPass should work on every system.
 *
 * @author      Marcus Krause <marcus#exp2009@t3sec.info>
 *
 * @since       2009-09-06
 * @package     TYPO3
 * @subpackage  tx_saltedpasswords
 */
class tx_saltedpasswords_salts_phpass extends tx_saltedpasswords_abstract_salts implements tx_saltedpasswords_salts {
    /**
     * Keeps a string for mapping an int to the corresponding
     * base 64 character.
     */
    const ITOA64 = './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';

    /**
     * The default log2 number of iterations for password stretching.
     */
    const HASH_COUNT = 14;

    /**
     * The default maximum allowed log2 number of iterations for
     * password stretching.
     */
    const MAX_HASH_COUNT = 24;

    /**
     * The default minimum allowed log2 number of iterations for
     * password stretching.
     */
    const MIN_HASH_COUNT = 7;


    /**
     * Keeps log2 number
     * of iterations for password stretching.
     *
     * @var integer
     */
    static protected $hashCount;

    /**
     * Keeps maximum allowed log2 number
     * of iterations for password stretching.
     *
     * @var integer
     */
    static protected $maxHashCount;

    /**
     * Keeps minimum allowed log2 number
     * of iterations for password stretching.
     *
     * @var integer
     */
    static protected $minHashCount;

    /**
     * Keeps length of a PHPass salt in bytes.
     *
     * @var integer
     */
    static protected $saltLengthPhpass = 6;

    /**
     * Setting string to indicate type of hashing method (PHPass).
     *
     * @var string
     */
    static protected $settingPhpass = '$P$';


    /**
     * Method applies settings (prefix, hash count) to a salt.
     *
     * Overwrites {@link tx_saltedpasswords_salts_md5::applySettingsToSalt()}
     * with Blowfish specifics.
     *
     * @param   string      $salt: a salt to apply setting to
     * @return  string      salt with setting
     */
    protected function applySettingsToSalt($salt) {
        $saltWithSettings = $salt;

        $reqLenBase64 = $this->getLengthBase64FromBytes($this->getSaltLength());

            // salt without setting
        if (strlen($salt) == $reqLenBase64) {
                // We encode the final log2 iteration count in base 64.
            $itoa64 = $this->getItoa64();
            $saltWithSettings = $this->getSetting() . $itoa64[$this->getHashCount()];

            $saltWithSettings .= $salt;
        }

        return $saltWithSettings;
    }

    /**
     * Method checks if a given plaintext password is correct by comparing it with
     * a given salted hashed password.
     *
     * @param   string      $plainPW: plain-text password to compare with salted hash
     * @param   string      $saltedHashPW: salted hash to compare plain-text password with
     * @return  boolean     TRUE, if plain-text password matches the salted hash, otherwise FALSE
     */
    public function checkPassword($plainPW, $saltedHashPW) {
        $hash = $this->cryptPassword($plainPW, $saltedHashPW);

        return ($hash && $saltedHashPW === $hash);
    }

    /**
     * Returns wether all prequesites for the hashing methods are matched
     *
     * @return  boolean     method available
     */
    public function isAvailable() {
        return TRUE;
    }

    /**
     * Hashes a password using a secure stretched hash.
     *
     * By using a salt and repeated hashing the password is "stretched". Its
     * security is increased because it becomes much more computationally costly
     * for an attacker to try to break the hash by brute-force computation of the
     * hashes of a large number of plain-text words or strings to find a match.
     *
     * @param   string      $password: plain-text password to hash
     * @param   string      $setting: an existing hash or the output of getGeneratedSalt()
     * @return  mixed       a string containing the hashed password (and salt)
     *                      or boolean FALSE on failure.
     */
    protected function cryptPassword($password, $setting) {
        $saltedPW = NULL;

        $reqLenBase64 = $this->getLengthBase64FromBytes($this->getSaltLength());

            // Retrieving settings with salt
        $setting = substr($setting, 0, strlen($this->getSetting()) + 1 + $reqLenBase64);

        $count_log2 = $this->getCountLog2($setting);

            // Hashes may be imported from elsewhere, so we allow != HASH_COUNT
        if ($count_log2 >= $this->getMinHashCount() && $count_log2 <= $this->getMaxHashCount()) {

            $salt = substr($setting, strlen($this->getSetting()) + 1, $reqLenBase64);

                // We must use md5() or sha1() here since they are the only cryptographic
                // primitives always available in PHP 5. To implement our own low-level
                // cryptographic function in PHP would result in much worse performance and
                // consequently in lower iteration counts and hashes that are quicker to crack
                // (by non-PHP code).
            $count = 1 << $count_log2;

            $hash = md5($salt . $password, TRUE);
            do {
                $hash = md5($hash . $password, TRUE);
            } while (--$count);

            $saltedPW =  $setting . $this->base64Encode($hash, 16);

                // base64Encode() of a 16 byte MD5 will always be 22 characters.
            return (strlen($saltedPW) == 34) ? $saltedPW : FALSE;
        }

        return $saltedPW;
    }

    /**
     * Parses the log2 iteration count from a stored hash or setting string.
     *
     * @param   string      $setting: complete hash or a hash's setting string or to get log2 iteration count from
     * @return  int         used hashcount for given hash string
     */
    protected function getCountLog2($setting) {
        return strpos(
            $this->getItoa64(),
            $setting[strlen($this->getSetting())]
        );
    }

    /**
     * Generates a random base 64-encoded salt prefixed and suffixed with settings for the hash.
     *
     * Proper use of salts may defeat a number of attacks, including:
     *  - The ability to try candidate passwords against multiple hashes at once.
     *  - The ability to use pre-hashed lists of candidate passwords.
     *  - The ability to determine whether two users have the same (or different)
     *    password without actually having to guess one of the passwords.
     *
     * @return  string      a character string containing settings and a random salt
     */
    protected function getGeneratedSalt() {
        $randomBytes = t3lib_div::generateRandomBytes($this->getSaltLength());

        return $this->base64Encode($randomBytes, $this->getSaltLength());
    }

    /**
     * Method returns log2 number of iterations for password stretching.
     *
     * @return  integer     log2 number of iterations for password stretching
     * @see     HASH_COUNT
     * @see     $hashCount
     * @see     setHashCount()
     */
    public function getHashCount() {
        return isset(self::$hashCount) ? self::$hashCount : self::HASH_COUNT;
    }

    /**
     * Method creates a salted hash for a given plaintext password
     *
     * @param   string      $password: plaintext password to create a salted hash from
     * @param   string      $salt: optional custom salt with setting to use
     * @return  string      salted hashed password
     */
    public function getHashedPassword($password, $salt = NULL) {
        $saltedPW = NULL;

        if (!empty($password)) {
            if (empty($salt) || !$this->isValidSalt($salt)) {
                $salt = $this->getGeneratedSalt();
            }
            $saltedPW = $this->cryptPassword($password, $this->applySettingsToSalt($salt));
        }

        return $saltedPW;
    }

    /**
     * Returns a string for mapping an int to the corresponding base 64 character.
     *
     * @return  string      string for mapping an int to the corresponding base 64 character
     */
    protected function getItoa64() {
        return self::ITOA64;
    }

    /**
     * Method returns maximum allowed log2 number of iterations for password stretching.
     *
     * @return  integer     maximum allowed log2 number of iterations for password stretching
     * @see     MAX_HASH_COUNT
     * @see     $maxHashCount
     * @see     setMaxHashCount()
     */
    public function getMaxHashCount() {
        return isset(self::$maxHashCount) ? self::$maxHashCount : self::MAX_HASH_COUNT;
    }

    /**
     * Method returns minimum allowed log2 number of iterations for password stretching.
     *
     * @return  integer     minimum allowed log2 number of iterations for password stretching
     * @see     MIN_HASH_COUNT
     * @see     $minHashCount
     * @see     setMinHashCount()
     */
    public function getMinHashCount() {
        return isset(self::$minHashCount) ? self::$minHashCount : self::MIN_HASH_COUNT;
    }

    /**
     * Returns length of a Blowfish salt in bytes.
     *
     * @return  integer     length of a Blowfish salt in bytes
     */
    public function getSaltLength() {
        return self::$saltLengthPhpass;
    }

    /**
     * Returns setting string of PHPass salted hashes.
     *
     * @return  string      setting string of PHPass salted hashes
     */
    public function getSetting() {
        return self::$settingPhpass;
    }

    /**
     * Checks whether a user's hashed password needs to be replaced with a new hash.
     *
     * This is typically called during the login process when the plain text
     * password is available.  A new hash is needed when the desired iteration
     * count has changed through a change in the variable $hashCount or
     * HASH_COUNT or if the user's password hash was generated in an bulk update
     * with class ext_update.
     *
     * @param   string      $passString  salted hash to check if it needs an update
     * @return  boolean     TRUE if salted hash needs an update, otherwise FALSE
     */
    public function isHashUpdateNeeded($passString) {
            // Check whether this was an updated password.
        if ((strncmp($passString, '$P$', 3)) || (strlen($passString) != 34)) {
            return TRUE;
        }
            // Check whether the iteration count used differs from the standard number.
        return ($this->getCountLog2($passString) < $this->getHashCount());
    }

    /**
     * Method determines if a given string is a valid salt.
     *
     * @param   string      $salt:  string to check
     * @return  boolean     TRUE if it's valid salt, otherwise FALSE
     */
    public function isValidSalt($salt) {
        $isValid = $skip = FALSE;

        $reqLenBase64 = $this->getLengthBase64FromBytes($this->getSaltLength());

        if (strlen($salt) >= $reqLenBase64) {
                // salt with prefixed setting
            if (!strncmp('$', $salt, 1)) {
                if (!strncmp($this->getSetting(), $salt, strlen($this->getSetting()))) {
                    $isValid = TRUE;
                    $salt = substr($salt, strrpos($salt, '$') + 2);
                } else {
                    $skip = TRUE;
                }
            }

                // checking base64 characters
            if (!$skip && (strlen($salt) >= $reqLenBase64)) {
                if (preg_match('/^[' . preg_quote($this->getItoa64(),'/') . ']{' . $reqLenBase64 . ',' . $reqLenBase64 . '}$/', substr($salt, 0, $reqLenBase64))) {
                    $isValid = TRUE;
                }
            }
        }

        return $isValid;
    }

    /**
     * Method determines if a given string is a valid salted hashed password.
     *
     * @param   string      $saltedPW: string to check
     * @return  boolean     TRUE if it's valid salted hashed password, otherwise FALSE
     */
    public function isValidSaltedPW($saltedPW) {
        $isValid = FALSE;

        $isValid = (!strncmp($this->getSetting(), $saltedPW, strlen($this->getSetting()))) ? TRUE : FALSE;
        if ($isValid) {
            $isValid = $this->isValidSalt($saltedPW);
        }

        return $isValid;
    }

    /**
     * Method sets log2 number of iterations for password stretching.
     *
     * @param   integer     $hashCount: log2 number of iterations for password stretching to set
     * @see     HASH_COUNT
     * @see     $hashCount
     * @see     getHashCount()
     */
    public function setHashCount($hashCount = NULL) {
        self::$hashCount = !is_NULL($hashCount) && is_int($hashCount) && $hashCount >= $this->getMinHashCount() && $hashCount <= $this->getMaxHashCount() ? $hashCount : self::HASH_COUNT;
    }

    /**
     * Method sets maximum allowed log2 number of iterations for password stretching.
     *
     * @param   integer     $maxHashCount: maximum allowed log2 number of iterations for password stretching to set
     * @see     MAX_HASH_COUNT
     * @see     $maxHashCount
     * @see     getMaxHashCount()
     */
    public function setMaxHashCount($maxHashCount = NULL) {
        self::$maxHashCount = !is_NULL($maxHashCount) && is_int($maxHashCount) ? $maxHashCount : self::MAX_HASH_COUNT;
    }

    /**
     * Method sets minimum allowed log2 number of iterations for password stretching.
     *
     * @param   integer     $minHashCount  minimum allowed log2 number of iterations for password stretching to set
     * @see     MIN_HASH_COUNT
     * @see     $minHashCount
     * @see     getMinHashCount()
     */
    public function setMinHashCount($minHashCount = NULL) {
        self::$minHashCount = !is_NULL($minHashCount) && is_int($minHashCount) ? $minHashCount : self::MIN_HASH_COUNT;
    }
}


if (defined('TYPO3_MODE') && isset($GLOBALS['TYPO3_CONF_VARS'][TYPO3_MODE]['XCLASS']['ext/saltedpasswords/classes/salts/class.tx_saltedpasswords_salts_phpass.php'])) {
    include_once($GLOBALS['TYPO3_CONF_VARS'][TYPO3_MODE]['XCLASS']['ext/saltedpasswords/classes/salts/class.tx_saltedpasswords_salts_phpass.php']);
}
?>