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 /* **checkid_immediate is not supported (yet)**, which means that we will
  59  * always ask for confirmation before redirecting to a third-party.
  60  * A sensible way to implement it would be to add a "Always trust this site"
  61  * checkbox to the form, and to store trusted websites per user. This still
  62  * raises the question of removing websites from that list.
  63  * Another possibility is to maintain a global whitelist.
  64  */
  65
  66 class OpenidModule extends PLModule
  67 {
  68     function handlers()
  69     {
  70         return array(
  71             'openid'            => $this->make_hook('openid', AUTH_PUBLIC),
  72             'openid/trust'      => $this->make_hook('trust', AUTH_COOKIE),
  73             'openid/idp_xrds'   => $this->make_hook('idp_xrds', AUTH_PUBLIC),
  74             'openid/user_xrds'  => $this->make_hook('user_xrds', AUTH_PUBLIC),
  75             'openid/melix'      => $this->make_hook('melix', AUTH_PUBLIC),
  76         );
  77     }
  78
  79     function handler_openid(&$page, $x = null)
  80     {
  81         $this->load('openid.inc.php');
  82
  83         // Spec §4.1.2: if "openid.mode" is absent, whe SHOULD assume that
  84         // the request is not an OpenId message
  85         // Thus, we try to render the discovery page
  86         if (!array_key_exists('openid_mode', $_REQUEST)) {
  87             return $this->render_discovery_page($page, get_user($x));
  88         }
  89
  90         // Now, deal with the OpenId message
  91         // Create a server and decode the request
  92         $server = init_openid_server();
  93         $request = $server->decodeRequest();
  94
  95         // With these modes, the request needs some logic
  96         // and can not be automatically answered by the server
  97         if (in_array($request->mode,
  98                      array('checkid_immediate', 'checkid_setup'))) {
  99
 100             // User identifier selection
 101             // if the user identifier is not known by the RP yet
 102             if ($request->idSelect()) {
 103                 if ($request->mode == 'checkid_immediate') {
 104                     // Deny authentication if we can't interact with the user
 105                     $response =& $request->answer(false);
 106                 } else {
 107                     // Otherwise save request in session and redirect
 108                     // to a page that requires authentication
 109                     // Then the user will be known
 110                     S::set('openid_request', serialize($request));
 111                     pl_redirect('openid/trust');
 112                     return;
 113                 }
 114
 115             // If don't use identifier selection and don't have an identifier,
 116             // give up
 117             } else if (!$request->identity) {
 118                 $this->render_no_identifier_page($page, $request);
 119                 return;
 120
 121             // From now on we have an identifier
 122
 123             // We deny immediate requests, unless the user is logged in
 124             // and has whitelisted the site
 125             } else if ($request->immediate) {
 126                 $answer = S::logged() && is_trusted_site(S::user(),
 127                                                          $request->trust_root);
 128                 $response =& $request->answer($answer);
 129
 130             // For setup requests, we redirect to a page where the user
 131             // will authenticate and confirm the use of his/her OpenId
 132             } else {
 133                 // Save request in session before jumping to confirmation page
 134                 S::set('openid_request', serialize($request));
 135                 pl_redirect('openid/trust');
 136                 return;
 137             }
 138
 139         // Other requests can be automatically handled by the server
 140         } else {
 141             $response =& $server->handleRequest($request);
 142         }
 143
 144         // Render response
 145         $webresponse =& $server->encodeResponse($response);
 146         $this->render_openid_response($webresponse);
 147     }
 148
 149     function handler_trust(&$page, $x = null)
 150     {
 151         $this->load('openid.inc.php');
 152
 153         // Recover request in session
 154         $request = S::v('openid_request');
 155         if (is_null($request)) {
 156             // There is no authentication information, something went wrong
 157             pl_redirect('/');
 158             return;
 159         }
 160
 161         // Unserialize the request
 162         require_once 'Auth/OpenID/Server.php';
 163         $request = unserialize($request);
 164
 165         $server = init_openid_server();
 166         $user = S::user();
 167         $identity = null;
 168         $claimed_id = null;
 169
 170         // Set the identity to the user currently logged in
 171         // if an OP Identifier was initially used
 172         if ($request->identity == Auth_OpenID_IDENTIFIER_SELECT) {
 173             $identity = $user->hruid;
 174             $claimed_id = get_user_openid_url($user);
 175         // Check that the identity matches the user currently logged in
 176         // if an User Identifier was initially used
 177         } else if ($request->identity != $user->hruid) {
 178             $response =& $request->answer(false);
 179             $webresponse =& $server->encodeResponse($response);
 180             $this->render_openid_response($webresponse);
 181             return;
 182         }
 183
 184         // Prepare Simple Registration response fields
 185         require_once 'Auth/OpenID/SReg.php';
 186         $sreg_request = Auth_OpenID_SRegRequest::fromOpenIDRequest($request);
 187         $sreg_response = Auth_OpenID_SRegResponse::extractResponse($sreg_request, get_sreg_data($user));
 188
 189         // Check the whitelist
 190         $whitelisted = is_trusted_site($user, $request->trust_root);
 191
 192         // Ask the user for confirmation
 193         if (!$whitelisted && $_SERVER['REQUEST_METHOD'] != 'POST') {
 194             $page->changeTpl('openid/trust.tpl');
 195             $page->assign('relying_party', $request->trust_root);
 196             $page->assign_by_ref('sreg_data', $sreg_response->data);
 197             return;
 198         }
 199
 200         // At this point $_SERVER['REQUEST_METHOD'] == 'POST'
 201         // Answer to the Relying Party
 202         if ($whitelisted || isset($_POST['trust'])) {
 203             S::kill('openid_request');
 204             $response =& $request->answer(true, null, $identity, $claimed_id);
 205
 206             // Add the simple registration response values to the OpenID
 207             // response message.
 208             $sreg_response->toMessage($response->fields);
 209
 210         } else { // !$whitelisted && !isset($_POST['trust'])
 211             S::kill('openid_request');
 212             $response =& $request->answer(false);
 213         }
 214
 215         // Generate a response to send to the user agent.
 216         $webresponse =& $server->encodeResponse($response);
 217         $this->render_openid_response($webresponse);
 218     }
 219
 220     function handler_idp_xrds(&$page)
 221     {
 222         $this->load('openid.inc.php');
 223
 224         // Set XRDS content-type and template
 225         header('Content-type: application/xrds+xml');
 226         $page->changeTpl('openid/idp_xrds.tpl', NO_SKIN);
 227
 228         // Set variables
 229         $page->assign('type2', Auth_OpenID_TYPE_2_0_IDP);
 230         $page->assign('sreg', Auth_OpenID_SREG_URI);
 231         $page->assign('provider', get_openid_url());
 232     }
 233
 234     function handler_user_xrds(&$page, $x = null)
 235     {
 236         $this->load('openid.inc.php');
 237
 238         // Make sure the user exists
 239         $user = get_user($x);
 240         if (is_null($user)) {
 241             return PL_NOT_FOUND;
 242         }
 243
 244         // Set XRDS content-type and template
 245         header('Content-type: application/xrds+xml');
 246         $page->changeTpl('openid/user_xrds.tpl', NO_SKIN);
 247
 248         // Set variables
 249         $page->assign('type2', Auth_OpenID_TYPE_2_0);
 250         $page->assign('type1', Auth_OpenID_TYPE_1_1);
 251         $page->assign('sreg', Auth_OpenID_SREG_URI);
 252         $page->assign('provider', get_openid_url());
 253         $page->assign('local_id', $user->hruid);
 254     }
 255
 256     function handler_melix(&$page, $x = null)
 257     {
 258         $this->load('openid.inc.php');
 259         $user = get_user_by_alias($x);
 260
 261         // This will redirect to the canonic URL, which was not used
 262         // if this hook was triggered
 263         return $this->render_discovery_page(&$page, $user);
 264     }
 265
 266     //--------------------------------------------------------------------//
 267
 268     function render_discovery_page(&$page, $user)
 269     {
 270
 271         // Show the documentation if this is not the OpenId page of an user
 272         if (is_null($user)) {
 273             pl_redirect('Xorg/OpenId');
 274         }
 275
 276         // Redirect to the canonic URL if we are using an alias
 277         // There might be a risk of redirection loop here
 278         // if $_SERVER was not exactly what we expect
 279         $current_url = 'http' . (empty($_SERVER['HTTPS']) ? '' : 's') . '://'
 280                        . $_SERVER['SERVER_NAME'] . $_SERVER['REQUEST_URI'];
 281         $canonic_url = get_user_openid_url($user);
 282         if ($current_url != $canonic_url) {
 283             http_redirect($canonic_url);
 284         }
 285
 286         // Include X-XRDS-Location response-header for Yadis discovery
 287         header('X-XRDS-Location: ' . get_user_xrds_url($user));
 288
 289         // Select template
 290         $page->changeTpl('openid/openid.tpl');
 291
 292         // Sets the title of the html page.
 293         $page->setTitle($user->fullName());
 294
 295         // Sets the <link> tags for HTML-Based Discovery
 296         $page->addLink('openid.server openid2.provider', get_openid_url());
 297         $page->addLink('openid.delegate openid2.local_id', $user->hruid);
 298
 299         // Adds the global user property array to the display.
 300         $page->assign_by_ref('user', $user);
 301
 302         return;
 303     }
 304
 305     function render_no_identifier_page($page, $request)
 306     {
 307         // Select template
 308         $page->changeTpl('openid/no_identifier.tpl');
 309     }
 310
 311     function render_openid_response($webresponse)
 312     {
 313         // Send HTTP response code
 314         if ($webresponse->code != AUTH_OPENID_HTTP_OK) {
 315             header(sprintf("HTTP/1.1 %d ", $webresponse->code),
 316                    true, $webresponse->code);
 317         }
 318
 319         // Send headers
 320         foreach ($webresponse->headers as $k => $v) {
 321             header("$k: $v");
 322         }
 323         header('Connection: close');
 324
 325         // Send body
 326         print $webresponse->body;
 327         exit;
 328     }
 329 }
 330
 331 // vim:set et sw=4 sts=4 sws=4 foldmethod=marker enc=utf-8:
 332 ?>