cakephp/src/Auth/DigestAuthenticate.php

<?php
/**
 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * For full copyright and license information, please see the LICENSE.txt
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://cakephp.org CakePHP(tm) Project
 * @since         2.0.0
 * @license       http://www.opensource.org/licenses/mit-license.php MIT License
 */
namespace Cake\Auth;

use Cake\Auth\BasicAuthenticate;
use Cake\Controller\ComponentRegistry;
use Cake\Network\Request;

/**
 * Digest Authentication adapter for AuthComponent.
 *
 * Provides Digest HTTP authentication support for AuthComponent.
 *
 * ### Using Digest auth
 *
 * In your controller's components array, add auth + the required config
 * {{{
 *	public $components = [
 *		'Auth' => [
 *			'authenticate' => ['Digest']
 *		]
 *	];
 * }}}
 *
 * You should also set `AuthComponent::$sessionKey = false;` in your AppController's
 * beforeFilter() to prevent CakePHP from sending a session cookie to the client.
 *
 * Since HTTP Digest Authentication is stateless you don't need a login() action
 * in your controller. The user credentials will be checked on each request. If
 * valid credentials are not provided, required authentication headers will be sent
 * by this authentication provider which triggers the login dialog in the browser/client.
 *
 * You may also want to use `$this->Auth->unauthorizedRedirect = false;`.
 * This causes AuthComponent to throw a ForbiddenException exception instead of
 * redirecting to another page.
 *
 * ### Generating passwords compatible with Digest authentication.
 *
 * DigestAuthenticate requires a special password hash that conforms to RFC2617.
 * You can generate this password using `DigestAuthenticate::password()`
 *
 * `$digestPass = DigestAuthenticate::password($username, env('SERVER_NAME'), $password);`
 *
 * If you wish to use digest authentication alongside other authentication methods,
 * its recommended that you store the digest authentication separately. For
 * example `User.digest_pass` could be used for a digest password, while
 * `User.password` would store the password hash for use with other methods like
 * Basic or Form.
 */
class DigestAuthenticate extends BasicAuthenticate {

/**
 * Constructor
 *
 * Besides the keys specified in BaseAuthenticate::$_defaultConfig,
 * DigestAuthenticate uses the following extra keys:
 *
 * - `realm` The realm authentication is for, Defaults to the servername.
 * - `nonce` A nonce used for authentication. Defaults to `uniqid()`.
 * - `qop` Defaults to 'auth', no other values are supported at this time.
 * - `opaque` A string that must be returned unchanged by clients.
 *    Defaults to `md5($config['realm'])`
 *
 * @param \Cake\Controller\ComponentRegistry $registry The Component registry
 *   used on this request.
 * @param array $config Array of config to use.
 */
	public function __construct(ComponentRegistry $registry, $config) {
		$this->_registry = $registry;

		$this->config([
			'realm' => null,
			'qop' => 'auth',
			'nonce' => uniqid(''),
			'opaque' => null,
		]);

		$this->config($config);
	}

/**
 * Get a user based on information in the request. Used by cookie-less auth for stateless clients.
 *
 * @param \Cake\Network\Request $request Request object.
 * @return mixed Either false or an array of user information
 */
	public function getUser(Request $request) {
		$digest = $this->_getDigest($request);
		if (empty($digest)) {
			return false;
		}

		list(, $model) = pluginSplit($this->_config['userModel']);
		$user = $this->_findUser($digest['username']);
		if (empty($user)) {
			return false;
		}

		$field = $this->_config['fields']['password'];
		$password = $user[$field];
		unset($user[$field]);

		$hash = $this->generateResponseHash($digest, $password, $request->env('REQUEST_METHOD'));
		if ($digest['response'] === $hash) {
			return $user;
		}
		return false;
	}

/**
 * Gets the digest headers from the request/environment.
 *
 * @param \Cake\Network\Request $request Request object.
 * @return array Array of digest information.
 */
	protected function _getDigest(Request $request) {
		$digest = $request->env('PHP_AUTH_DIGEST');
		if (empty($digest) && function_exists('apache_request_headers')) {
			$headers = apache_request_headers();
			if (!empty($headers['Authorization']) && substr($headers['Authorization'], 0, 7) === 'Digest ') {
				$digest = substr($headers['Authorization'], 7);
			}
		}
		if (empty($digest)) {
			return false;
		}
		return $this->parseAuthData($digest);
	}

/**
 * Parse the digest authentication headers and split them up.
 *
 * @param string $digest The raw digest authentication headers.
 * @return array An array of digest authentication headers
 */
	public function parseAuthData($digest) {
		if (substr($digest, 0, 7) === 'Digest ') {
			$digest = substr($digest, 7);
		}
		$keys = $match = array();
		$req = array('nonce' => 1, 'nc' => 1, 'cnonce' => 1, 'qop' => 1, 'username' => 1, 'uri' => 1, 'response' => 1);
		preg_match_all('/(\w+)=([\'"]?)([a-zA-Z0-9\:\#\%@=.\/_-]+)\2/', $digest, $match, PREG_SET_ORDER);

		foreach ($match as $i) {
			$keys[$i[1]] = $i[3];
			unset($req[$i[1]]);
		}

		if (empty($req)) {
			return $keys;
		}
		return null;
	}

/**
 * Generate the response hash for a given digest array.
 *
 * @param array $digest Digest information containing data from DigestAuthenticate::parseAuthData().
 * @param string $password The digest hash password generated with DigestAuthenticate::password()
 * @param string $method Request method
 * @return string Response hash
 */
	public function generateResponseHash($digest, $password, $method) {
		return md5(
			$password .
			':' . $digest['nonce'] . ':' . $digest['nc'] . ':' . $digest['cnonce'] . ':' . $digest['qop'] . ':' .
			md5($method . ':' . $digest['uri'])
		);
	}

/**
 * Creates an auth digest password hash to store
 *
 * @param string $username The username to use in the digest hash.
 * @param string $password The unhashed password to make a digest hash for.
 * @param string $realm The realm the password is for.
 * @return string the hashed password that can later be used with Digest authentication.
 */
	public static function password($username, $password, $realm) {
		return md5($username . ':' . $realm . ':' . $password);
	}

/**
 * Generate the login headers
 *
 * @param \Cake\Network\Request $request Request object.
 * @return string Headers for logging in.
 */
	public function loginHeaders(Request $request) {
		$realm = $this->_config['realm'] ?: $request->env('SERVER_NAME');

		$options = array(
			'realm' => $realm,
			'qop' => $this->_config['qop'],
			'nonce' => $this->_config['nonce'],
			'opaque' => $this->_config['opaque'] ?: md5($realm)
		);

		$opts = array();
		foreach ($options as $k => $v) {
			$opts[] = sprintf('%s="%s"', $k, $v);
		}
		return 'WWW-Authenticate: Digest ' . implode(',', $opts);
	}

}