class.tx_saltedpasswords_salts_md5.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.
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***************************************************************/
/**
 * Contains class "tx_saltedpasswords_salts_md5"
 * that provides MD5 salted hashing.
 *
 * $Id: class.tx_saltedpasswords_salts_md5.php 10120 2011-01-18 20:03:36Z ohader $
 */


/**
 * Class that implements MD5 salted hashing based on PHP's
 * crypt() function.
 *
 * MD5 salted hashing with PHP's crypt() should be available
 * on most of the systems.
 *
 * @author      Marcus Krause <marcus#exp2009@t3sec.info>
 *
 * @since       2009-09-06
 * @package     TYPO3
 * @subpackage  tx_saltedpasswords
 */
class tx_saltedpasswords_salts_md5 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';

    /**
     * Keeps length of a MD5 salt in bytes.
     *
     * @var integer
     */
    static protected $saltLengthMD5 = 6;

    /**
     * Keeps suffix to be appended to a salt.
     *
     * @var string
     */
    static protected $saltSuffixMD5 = '$';

    /**
     * Setting string to indicate type of hashing method (md5).
     *
     * @var string
     */
    static protected $settingMD5 = '$1$';


    /**
     * Method applies settings (prefix, suffix) to a salt.
     *
     * @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) {
            $saltWithSettings = $this->getSetting() . $salt . $this->getSaltSuffix();

        }

        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) {
        $isCorrect = FALSE;

        if ($this->isValidSalt($saltedHashPW)) {
            $isCorrect = (crypt($plainPW,$saltedHashPW) == $saltedHashPW);
        }

        return $isCorrect;
    }

    /**
     * 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 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();
            }
            $saltedPW = crypt($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;
    }

    /**
     * Returns wether all prequesites for the hashing methods are matched
     *
     * @return  boolean     method available
     */
    public function isAvailable() {
        return CRYPT_MD5;
    }

    /**
     * Returns length of a MD5 salt in bytes.
     *
     * @return  integer     length of a MD5 salt in bytes
     */
    public function getSaltLength() {
        return self::$saltLengthMD5;
    }

    /**
     * Returns suffix to be appended to a salt.
     *
     * @return  string      suffix of a salt
     */
    protected function getSaltSuffix() {
        return self::$saltSuffixMD5;
    }

    /**
     * Returns setting string of MD5 salted hashes.
     *
     * @return  string      setting string of MD5 salted hashes
     */
    public function getSetting() {
        return self::$settingMD5;
    }

    /**
     * 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) {
        return FALSE;
    }

    /**
     * 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, strlen($this->getSetting()));
                } 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;
    }
}


if (defined('TYPO3_MODE') && isset($GLOBALS['TYPO3_CONF_VARS'][TYPO3_MODE]['XCLASS']['ext/saltedpasswords/classes/salts/class.tx_saltedpasswords_salts_md5.php'])) {
    include_once($GLOBALS['TYPO3_CONF_VARS'][TYPO3_MODE]['XCLASS']['ext/saltedpasswords/classes/salts/class.tx_saltedpasswords_salts_md5.php']);
}
?>