appwrite/src/Appwrite/Auth/Hash/PHPass.php

<?php
/**
 * Portable PHP password hashing framework.
 * source Version 0.5 / genuine.
 * Written by Solar Designer <solar at openwall.com> in 2004-2017 and placed in
 * the public domain.  Revised in subsequent years, still public domain.
 * There's absolutely no warranty.
 * The homepage URL for the source framework is: http://www.openwall.com/phpass/
 * Please be sure to update the Version line if you edit this file in any way.
 * It is suggested that you leave the main version number intact, but indicate
 * your project name (after the slash) and add your own revision information.
 * Please do not change the "private" password hashing method implemented in
 * here, thereby making your hashes incompatible.  However, if you must, please
 * change the hash type identifier (the "$P$") to something different.
 * Obviously, since this code is in the public domain, the above are not
 * requirements (there can be none), but merely suggestions.
 *
 * @author      Solar Designer <solar@openwall.com>
 * @copyright   Copyright (C) 2017 All rights reserved.
 * @license     http://www.opensource.org/licenses/mit-license.html MIT License; see LICENSE.txt
 */

namespace Appwrite\Auth\Hash;

/**
 * PasswordHash class is a portable password hashing framework for use in PHP applications.
 *
 * @since       0.1
 */
class PHPass
{
	/**
	 * Alphabet used in itoa64 conversions.
	 *
	 * @var    string
	 * @since  0.1.0
	 */
	protected $itoa64 = './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';

	/**
	 * The Logarithmic cost value used when generating hash values indicating the number of rounds used to generate hashes
	 *
	 * @var    integer
	 * @since  0.1.0
	 */
	public $iteration_count_log2 = 12;

	/**
	 * The portable_hashes
	 *
	 * @var    string
	 * @since  0.1.0
	 */
	public $portable_hashes;

	/**
	 * The cached random state
	 *
	 * @var    string
	 * @since  0.1.0
	 */
	protected $random_state;

	/**
	 * Constructor
	 *
	 * @param int $iteration_count_log2 Logarithmic cost value used when generating hash values
	 * @param string $portable_hashes
	 *
	 * @since 0.5.0
	 */
	public function __construct($iteration_count_log2, $portable_hashes)
	{
		if ($iteration_count_log2 < 10) {
			// The minimum Logarithmic cost value
			$iteration_count_log2 = 10;
		} else {
			if ($iteration_count_log2 > 32) {
				// The maximum Logarithmic cost value
				$iteration_count_log2 = 32;
			}
		}
		$this->iteration_count_log2 = $iteration_count_log2;
		$this->portable_hashes = $portable_hashes;
		$this->random_state = microtime();
		if (function_exists('getmypid')) {
			$this->random_state .= getmypid();
		}
	}

	/**
	 * @param String $password
	 *
	 * @return String $hash
	 * @since 0.1.0
	 */
	public function hash($password)
	{
		$random = '';
		if (CRYPT_BLOWFISH === 1 && !$this->portable_hashes) {
			$random = $this->get_random_bytes(16);
			$hash = crypt($password, $this->gensalt_blowfish($random));
			if (strlen($hash) === 60) {
				return $hash;
			}
		}
		if (strlen($random) < 6) {
			$random = $this->get_random_bytes(6);
		}
		$hash = $this->crypt_private($password, $this->gensalt_private($random));
		if (strlen($hash) === 34) {
			return $hash;
		}

		/**
		 * Returning '*' on error is safe here, but would _not_ be safe
		 * in a crypt(3)-like function used _both_ for generating new
		 * hashes and for validating passwords against existing hashes.
		 */
		return '*';
	}

	/**
	 * @param String $password
	 * @param String $stored_hash
	 *
	 * @return boolean
	 * @since 0.1.0
	 */
	public function verify($password, $stored_hash)
	{
		$hash = $this->crypt_private($password, $stored_hash);
		if ($hash[0] === '*') {
			$hash = crypt($password, $stored_hash);
		}

		/**
		 * This is not constant-time.  In order to keep the code simple,
		 * for timing safety we currently rely on the salts being
		 * unpredictable, which they are at least in the non-fallback
		 * cases (that is, when we use /dev/urandom and bcrypt).
		 */
		return $hash === $stored_hash;
	}

	/**
	 *  A backwards compatible constructor
	 *
	 * @param int $iteration_count_log2 Logarithmic cost value used when generating hash values
	 * @param string $portable_hashes
	 *
	 * @since 0.1.0
	 */
	public function PasswordHash($iteration_count_log2, $portable_hashes)
	{
		self::__construct($iteration_count_log2, $portable_hashes);
	}

	/**
	 * @param  int $count
	 *
	 * @return String $output
	 * @since 0.1.0
	 * @throws InvalidArgumentException Thows an InvalidArgumentException if the $count parameter is not a positive integer.
	 */
	protected function get_random_bytes($count)
	{
		if (!is_int($count) || $count < 1) {
			throw new InvalidArgumentException('Argument count must be a positive integer');
		}
		$output = '';
		if (@is_readable('/dev/urandom') && ($fh = @fopen('/dev/urandom', 'rb'))) {
			$output = fread($fh, $count);
			fclose($fh);
		}

		if (strlen($output) < $count) {
			$output = '';

			for ($i = 0; $i < $count; $i += 16) {
				$this->random_state = md5(microtime() . $this->random_state);
				$output .= md5($this->random_state, TRUE);
			}

			$output = substr($output, 0, $count);
		}

		return $output;
	}

	/**
	 * @param  String $input
	 * @param  int $count
	 *
	 * @return String $output
	 * @since 0.1.0
	 * @throws InvalidArgumentException Thows an InvalidArgumentException if the $count parameter is not a positive integer.
	 */
	protected function encode64($input, $count)
	{
		if (!is_int($count) || $count < 1) {
			throw new InvalidArgumentException('Argument count must be a positive integer');
		}
		$output = '';
		$i = 0;
		do {
			$value = ord($input[$i++]);
			$output .= $this->itoa64[$value & 0x3f];
			if ($i < $count) {
				$value |= ord($input[$i]) << 8;
			}
			$output .= $this->itoa64[($value >> 6) & 0x3f];
			if ($i++ >= $count) {
				break;
			}
			if ($i < $count) {
				$value |= ord($input[$i]) << 16;
			}
			$output .= $this->itoa64[($value >> 12) & 0x3f];
			if ($i++ >= $count) {
				break;
			}
			$output .= $this->itoa64[($value >> 18) & 0x3f];
		} while ($i < $count);

		return $output;
	}

	/**
	 * @param  String $input
	 *
	 * @return String $output
	 * @since 0.1.0
	 */
	private function gensalt_private($input)
	{
		$output = '$P$';
		$output .= $this->itoa64[min($this->iteration_count_log2 + ((PHP_VERSION >= '5') ? 5 : 3), 30)];
		$output .= $this->encode64($input, 6);

		return $output;
	}

	/**
	 * @param  String $password
	 * @param  String $setting
	 *
	 * @return String $output
	 * @since 0.1.0
	 */
	private function crypt_private($password, $setting)
	{
		$output = '*0';
		if (substr($setting, 0, 2) === $output) {
			$output = '*1';
		}
		$id = substr($setting, 0, 3);
		// We use "$P$", phpBB3 uses "$H$" for the same thing
		if ($id !== '$P$' && $id !== '$H$') {
			return $output;
		}
		$count_log2 = strpos($this->itoa64, $setting[3]);
		if ($count_log2 < 7 || $count_log2 > 30) {
			return $output;
		}
		$count = 1 << $count_log2;
		$salt = substr($setting, 4, 8);
		if (strlen($salt) !== 8) {
			return $output;
		}
		/**
		 * We were kind of forced to use MD5 here since it's the only
		 * cryptographic primitive that was available in all versions of PHP
		 * in use.  To implement our own low-level crypto in PHP
		 * would have result in much worse performance and
		 * consequently in lower iteration counts and hashes that are
		 * quicker to crack (by non-PHP code).
		 */
		$hash = md5($salt . $password, TRUE);
		do {
			$hash = md5($hash . $password, TRUE);
		} while (--$count);
		$output = substr($setting, 0, 12);
		$output .= $this->encode64($hash, 16);

		return $output;
	}

	/**
	 * @param  String $input
	 *
	 * @return String $output
	 * @since 0.1.0
	 */
	private function gensalt_blowfish($input)
	{
		/**
		 * This one needs to use a different order of characters and a
		 * different encoding scheme from the one in encode64() above.
		 * We care because the last character in our encoded string will
		 * only represent 2 bits.  While two known implementations of
		 * bcrypt will happily accept and correct a salt string which
		 * has the 4 unused bits set to non-zero, we do not want to take
		 * chances and we also do not want to waste an additional byte
		 * of entropy.
		 */
		$itoa64 = './ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
		$output = '$2a$';
		$output .= chr(ord('0') + $this->iteration_count_log2 / 10);
		$output .= chr(ord('0') + $this->iteration_count_log2 % 10);
		$output .= '$';
		$i = 0;
		do {
			$c1 = ord($input[$i++]);
			$output .= $itoa64[$c1 >> 2];
			$c1 = ($c1 & 0x03) << 4;
			if ($i >= 16) {
				$output .= $itoa64[$c1];
				break;
			}
			$c2 = ord($input[$i++]);
			$c1 |= $c2 >> 4;
			$output .= $itoa64[$c1];
			$c1 = ($c2 & 0x0f) << 2;
			$c2 = ord($input[$i++]);
			$c1 |= $c2 >> 6;
			$output .= $itoa64[$c1];
			$output .= $itoa64[$c2 & 0x3f];
		} while (1);

		return $output;
	}
}