modules/openid.php

   1 <?php
   2 /***************************************************************************
   3  *  Copyright (C) 2003-2008 Polytechnique.org                              *
   4  *  http://opensource.polytechnique.org/                                   *
   5  *                                                                         *
   6  *  This program is free software; you can redistribute it and/or modify   *
   7  *  it under the terms of the GNU General Public License as published by   *
   8  *  the Free Software Foundation; either version 2 of the License, or      *
   9  *  (at your option) any later version.                                    *
  10  *                                                                         *
  11  *  This program is distributed in the hope that it will be useful,        *
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of         *
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the          *
  14  *  GNU General Public License for more details.                           *
  15  *                                                                         *
  16  *  You should have received a copy of the GNU General Public License      *
  17  *  along with this program; if not, write to the Free Software            *
  18  *  Foundation, Inc.,                                                      *
  19  *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA                *
  20  ***************************************************************************/
  21
  22
  23 /* Definitions for the OpenId Specification
  24  * http://openid.net/specs/openid-authentication-2_0.html
  25  *
  26  * OP Endpoint URL:             https://www.polytechnique.org/openid
  27  * OP Identifier:               https://www.polytechnique.org/openid
  28  * User Identifier:             https://www.polytechnique.org/openid/{hruid}
  29  * OP-Local Identifier:         {hruid}
  30  */
  31
  32 /* This implementation supports two modes:
  33  *     - entering the OP Identifier, which can simply be 'polytechnique.org'
  34  *     - entering the User Identifier, or some URL that resolves there
  35  * In both cases, Yadis discovery is made possible through the X-XRDS-Location
  36  * header.
  37  *
  38  * In the former case, Yadis discovery is performed on /, or where it redirects;
  39  * see platal.php. It resolves to the XRDS for this OP, and User Identifier
  40  * selection is performed after forcing the user to log in. This only works for
  41  * version 2.0 of the OpenId protocol.
  42  *
  43  * In the latter cas, Yadis discovery is performed on /openid/{hruid}. It
  44  * resolves ta a user-specific XRDS. This page also features HTML-based
  45  * discovery. This works with any version of the protocol.
  46  */
  47
  48 /* Testing suite is here:
  49  * http://openidenabled.com/resources/openid-test/
  50  * It only supports User Indentifiers.
  51  *
  52  * To test OP Identifiers, download the JanRain PHP library and use the
  53  * consumer provided as an example (although it appears that a failure is
  54  * mistakenly reported: 'Server denied check_authentication').
  55  * Reading the source of the server can also help understanding the code below.
  56  */
  57
  58
  59 class OpenidModule extends PLModule
  60 {
  61     function handlers()
  62     {
  63         return array(
  64             'openid'            => $this->make_hook('openid', AUTH_PUBLIC),
  65             'openid/trust'      => $this->make_hook('trust', AUTH_COOKIE),
  66             'openid/idp_xrds'   => $this->make_hook('idp_xrds', AUTH_PUBLIC),
  67             'openid/user_xrds'  => $this->make_hook('user_xrds', AUTH_PUBLIC),
  68             'openid/melix'      => $this->make_hook('melix', AUTH_PUBLIC),
  69         );
  70     }
  71
  72     function handler_openid(&$page, $x = null)
  73     {
  74         $this->load('openid.inc.php');
  75
  76         // Spec §4.1.2: if "openid.mode" is absent, we SHOULD assume that
  77         // the request is not an OpenId message
  78         if (!array_key_exists('openid_mode', $_REQUEST)) {
  79             return $this->render_discovery_page($page, get_user($x));
  80         }
  81
  82         // Now, deal with the OpenId message
  83         $server = init_openid_server();
  84         $request = $server->decodeRequest();
  85
  86         // In modes 'checkid_immediate' and 'checkid_setup', the request
  87         // needs some logic and can not be automatically answered by the server
  88
  89         // Immediate mode
  90         if ($request->mode == 'checkid_immediate') {
  91
  92             // We deny immediate requests, unless:
  93             //   - the user identifier is known by the RP
  94             //   - the user is logged in
  95             //   - the user identifier matches the user logged in
  96             //   - the user has whitelisted the site
  97             $answer = !$request->idSelect()
  98                       && S::logged()
  99                       && $request->identity == S::user()->login()
 100                       && is_trusted_site(S::user(), $request->trust_root);
 101             $response =& $request->answer($answer);
 102
 103         // Setup mode
 104         } else if ($request->mode == 'checkid_setup') {
 105
 106             // We redirect to a page where the user will authenticate
 107             // and confirm the use of his/her OpenId
 108             // The request is saved in session before redirecting
 109             S::set('openid_request', serialize($request));
 110             pl_redirect('openid/trust');
 111             return;
 112
 113         // Other requests can be automatically handled by the server
 114         } else {
 115             $response =& $server->handleRequest($request);
 116         }
 117
 118         $webresponse =& $server->encodeResponse($response);
 119         $this->render_openid_response($webresponse);
 120     }
 121
 122     function handler_trust(&$page, $x = null)
 123     {
 124         $this->load('openid.inc.php');
 125
 126         // Recover request in session
 127         $request = S::v('openid_request');
 128         if (is_null($request)) {
 129             // There is no authentication information, something went wrong
 130             pl_redirect('/');
 131             return;
 132         }
 133
 134         require_once 'Auth/OpenID/Server.php';
 135         $request = unserialize($request);
 136
 137         $server = init_openid_server();
 138         $user = S::user();
 139         $identity = null;
 140         $claimed_id = null;
 141
 142         // Set the identity to the user currently logged in
 143         // if an OP Identifier was initially used
 144         if ($request->identity == Auth_OpenID_IDENTIFIER_SELECT) {
 145             $identity = $user->hruid;
 146             $claimed_id = get_user_openid_url($user);
 147         // Check that the identity matches the user currently logged in
 148         // if an User Identifier was initially used
 149         } else if ($request->identity != $user->hruid) {
 150             $response =& $request->answer(false);
 151             $webresponse =& $server->encodeResponse($response);
 152             $this->render_openid_response($webresponse);
 153             return;
 154         }
 155
 156         // Prepare Simple Registration response fields
 157         require_once 'Auth/OpenID/SReg.php';
 158         $sreg_request = Auth_OpenID_SRegRequest::fromOpenIDRequest($request);
 159         $sreg_response = Auth_OpenID_SRegResponse::extractResponse($sreg_request, get_sreg_data($user));
 160
 161         $whitelisted = is_trusted_site($user, $request->trust_root);
 162
 163         // Ask the user for confirmation
 164         if (!$whitelisted && $_SERVER['REQUEST_METHOD'] != 'POST') {
 165             $page->changeTpl('openid/trust.tpl');
 166             $page->assign('relying_party', $request->trust_root);
 167             $page->assign_by_ref('sreg_data', $sreg_response->data);
 168             return;
 169         }
 170
 171         // At this point $_SERVER['REQUEST_METHOD'] == 'POST'
 172
 173         // Add 'always trusted' sites to whitelist
 174         if (isset($_POST['trust']) && @$_POST['always']) {
 175             add_trusted_site($user, $request->trust_root);
 176         }
 177
 178         // Answer to the Relying Party
 179         if ($whitelisted || isset($_POST['trust'])) {
 180             S::kill('openid_request');
 181             $response =& $request->answer(true, null, $identity, $claimed_id);
 182
 183             // Add the simple registration response values to the OpenID
 184             // response message.
 185             $sreg_response->toMessage($response->fields);
 186
 187         } else { // !$whitelisted && !isset($_POST['trust'])
 188             S::kill('openid_request');
 189             $response =& $request->answer(false);
 190         }
 191
 192         $webresponse =& $server->encodeResponse($response);
 193         $this->render_openid_response($webresponse);
 194     }
 195
 196     function handler_idp_xrds(&$page)
 197     {
 198         $this->load('openid.inc.php');
 199         header('Content-type: application/xrds+xml');
 200         $page->changeTpl('openid/idp_xrds.tpl', NO_SKIN);
 201         $page->assign('type2', Auth_OpenID_TYPE_2_0_IDP);
 202         $page->assign('sreg', Auth_OpenID_SREG_URI);
 203         $page->assign('provider', get_openid_url());
 204     }
 205
 206     function handler_user_xrds(&$page, $x = null)
 207     {
 208         $this->load('openid.inc.php');
 209
 210         $user = get_user($x);
 211         if (is_null($user)) {
 212             return PL_NOT_FOUND;
 213         }
 214
 215         header('Content-type: application/xrds+xml');
 216         $page->changeTpl('openid/user_xrds.tpl', NO_SKIN);
 217         $page->assign('type2', Auth_OpenID_TYPE_2_0);
 218         $page->assign('type1', Auth_OpenID_TYPE_1_1);
 219         $page->assign('sreg', Auth_OpenID_SREG_URI);
 220         $page->assign('provider', get_openid_url());
 221         $page->assign('local_id', $user->hruid);
 222     }
 223
 224     function handler_melix(&$page, $x = null)
 225     {
 226         $this->load('openid.inc.php');
 227         $user = get_user_by_alias($x);
 228
 229         // This will redirect to the canonic URL, which was not used
 230         // if this hook was triggered
 231         return $this->render_discovery_page(&$page, $user);
 232     }
 233
 234     //--------------------------------------------------------------------//
 235
 236     function render_discovery_page(&$page, $user)
 237     {
 238
 239         // Show the documentation if this is not the OpenId page of an user
 240         if (is_null($user)) {
 241             pl_redirect('Xorg/OpenId');
 242         }
 243
 244         // Redirect to the canonic URL if we are using an alias
 245         // There might be a risk of redirection loop here
 246         // if $_SERVER was not exactly what we expect
 247         $current_url = 'http' . (empty($_SERVER['HTTPS']) ? '' : 's') . '://'
 248                        . $_SERVER['SERVER_NAME'] . $_SERVER['REQUEST_URI'];
 249         $canonic_url = get_user_openid_url($user);
 250         if ($current_url != $canonic_url) {
 251             http_redirect($canonic_url);
 252         }
 253
 254         // Include X-XRDS-Location response-header for Yadis discovery
 255         header('X-XRDS-Location: ' . get_user_xrds_url($user));
 256
 257         $page->changeTpl('openid/openid.tpl');
 258         $page->setTitle($user->fullName());
 259         // Set the <link> tags for HTML-Based Discovery
 260         $page->addLink('openid.server openid2.provider', get_openid_url());
 261         $page->addLink('openid.delegate openid2.local_id', $user->hruid);
 262         $page->assign_by_ref('user', $user);
 263
 264         return;
 265     }
 266
 267     function render_openid_response($webresponse)
 268     {
 269         if ($webresponse->code != AUTH_OPENID_HTTP_OK) {
 270             header(sprintf("HTTP/1.1 %d ", $webresponse->code),
 271                    true, $webresponse->code);
 272         }
 273         foreach ($webresponse->headers as $k => $v) {
 274             header("$k: $v");
 275         }
 276         header('Connection: close');
 277         print $webresponse->body;
 278         exit;
 279     }
 280 }
 281
 282 // vim:set et sw=4 sts=4 sws=4 foldmethod=marker enc=utf-8:
 283 ?>