1: <?php
  2: /**
  3:  * Functions for dealing with OpenID trust roots
  4:  *
  5:  * PHP versions 4 and 5
  6:  *
  7:  * LICENSE: See the COPYING file included in this distribution.
  8:  *
  9:  * @package OpenID
 10:  * @author JanRain, Inc. <openid@janrain.com>
 11:  * @copyright 2005-2008 Janrain, Inc.
 12:  * @license http://www.apache.org/licenses/LICENSE-2.0 Apache
 13:  */
 14: 
 15: require_once 'Auth/OpenID/Discover.php';
 16: 
 17: /**
 18:  * A regular expression that matches a domain ending in a top-level domains.
 19:  * Used in checking trust roots for sanity.
 20:  *
 21:  * @access private
 22:  */
 23: define('Auth_OpenID___TLDs',
 24:        '/\.(ac|ad|ae|aero|af|ag|ai|al|am|an|ao|aq|ar|arpa|as|asia' .
 25:        '|at|au|aw|ax|az|ba|bb|bd|be|bf|bg|bh|bi|biz|bj|bm|bn|bo|br' .
 26:        '|bs|bt|bv|bw|by|bz|ca|cat|cc|cd|cf|cg|ch|ci|ck|cl|cm|cn|co' .
 27:        '|com|coop|cr|cu|cv|cx|cy|cz|de|dj|dk|dm|do|dz|ec|edu|ee|eg' .
 28:        '|er|es|et|eu|fi|fj|fk|fm|fo|fr|ga|gb|gd|ge|gf|gg|gh|gi|gl' .
 29:        '|gm|gn|gov|gp|gq|gr|gs|gt|gu|gw|gy|hk|hm|hn|hr|ht|hu|id|ie' .
 30:        '|il|im|in|info|int|io|iq|ir|is|it|je|jm|jo|jobs|jp|ke|kg|kh' .
 31:        '|ki|km|kn|kp|kr|kw|ky|kz|la|lb|lc|li|lk|lr|ls|lt|lu|lv|ly' .
 32:        '|ma|mc|md|me|mg|mh|mil|mk|ml|mm|mn|mo|mobi|mp|mq|mr|ms|mt' .
 33:        '|mu|museum|mv|mw|mx|my|mz|na|name|nc|ne|net|nf|ng|ni|nl|no' .
 34:        '|np|nr|nu|nz|om|org|pa|pe|pf|pg|ph|pk|pl|pm|pn|pr|pro|ps|pt' .
 35:        '|pw|py|qa|re|ro|rs|ru|rw|sa|sb|sc|sd|se|sg|sh|si|sj|sk|sl' .
 36:        '|sm|sn|so|sr|st|su|sv|sy|sz|tc|td|tel|tf|tg|th|tj|tk|tl|tm' .
 37:        '|tn|to|tp|tr|travel|tt|tv|tw|tz|ua|ug|uk|us|uy|uz|va|vc|ve' .
 38:        '|vg|vi|vn|vu|wf|ws|xn--0zwm56d|xn--11b5bs3a9aj6g' .
 39:        '|xn--80akhbyknj4f|xn--9t4b11yi5a|xn--deba0ad|xn--g6w251d' .
 40:        '|xn--hgbk6aj7f53bba|xn--hlcj6aya9esc7a|xn--jxalpdlp' .
 41:        '|xn--kgbechtv|xn--zckzah|ye|yt|yu|za|zm|zw)\.?$/');
 42: 
 43: define('Auth_OpenID___HostSegmentRe',
 44:        "/^(?:[-a-zA-Z0-9!$&'\\(\\)\\*+,;=._~]|%[a-zA-Z0-9]{2})*$/");
 45: 
 46: /**
 47:  * A wrapper for trust-root related functions
 48:  */
 49: class Auth_OpenID_TrustRoot {
 50:     /*
 51:      * Return a discovery URL for this realm.
 52:      *
 53:      * Return null if the realm could not be parsed or was not valid.
 54:      *
 55:      * @param return_to The relying party return URL of the OpenID
 56:      * authentication request
 57:      *
 58:      * @return The URL upon which relying party discovery should be
 59:      * run in order to verify the return_to URL
 60:      */
 61:     static function buildDiscoveryURL($realm)
 62:     {
 63:         $parsed = Auth_OpenID_TrustRoot::_parse($realm);
 64: 
 65:         if ($parsed === false) {
 66:             return false;
 67:         }
 68: 
 69:         if ($parsed['wildcard']) {
 70:             // Use "www." in place of the star
 71:             if ($parsed['host'][0] != '.') {
 72:                 return false;
 73:             }
 74: 
 75:             $www_domain = 'www' . $parsed['host'];
 76: 
 77:             return sprintf('%s://%s%s', $parsed['scheme'],
 78:                            $www_domain, $parsed['path']);
 79:         } else {
 80:             return $parsed['unparsed'];
 81:         }
 82:     }
 83: 
 84:     /**
 85:      * Parse a URL into its trust_root parts.
 86:      *
 87:      * @static
 88:      *
 89:      * @access private
 90:      *
 91:      * @param string $trust_root The url to parse
 92:      *
 93:      * @return mixed $parsed Either an associative array of trust root
 94:      * parts or false if parsing failed.
 95:      */
 96:     static function _parse($trust_root)
 97:     {
 98:         $trust_root = Auth_OpenID_urinorm($trust_root);
 99:         if ($trust_root === null) {
100:             return false;
101:         }
102: 
103:         if (preg_match("/:\/\/[^:]+(:\d+){2,}(\/|$)/", $trust_root)) {
104:             return false;
105:         }
106: 
107:         $parts = @parse_url($trust_root);
108:         if ($parts === false) {
109:             return false;
110:         }
111: 
112:         $required_parts = array('scheme', 'host');
113:         $forbidden_parts = array('user', 'pass', 'fragment');
114:         $keys = array_keys($parts);
115:         if (array_intersect($keys, $required_parts) != $required_parts) {
116:             return false;
117:         }
118: 
119:         if (array_intersect($keys, $forbidden_parts) != array()) {
120:             return false;
121:         }
122: 
123:         if (!preg_match(Auth_OpenID___HostSegmentRe, $parts['host'])) {
124:             return false;
125:         }
126: 
127:         $scheme = strtolower($parts['scheme']);
128:         $allowed_schemes = array('http', 'https');
129:         if (!in_array($scheme, $allowed_schemes)) {
130:             return false;
131:         }
132:         $parts['scheme'] = $scheme;
133: 
134:         $host = strtolower($parts['host']);
135:         $hostparts = explode('*', $host);
136:         switch (count($hostparts)) {
137:         case 1:
138:             $parts['wildcard'] = false;
139:             break;
140:         case 2:
141:             if ($hostparts[0] ||
142:                 ($hostparts[1] && substr($hostparts[1], 0, 1) != '.')) {
143:                 return false;
144:             }
145:             $host = $hostparts[1];
146:             $parts['wildcard'] = true;
147:             break;
148:         default:
149:             return false;
150:         }
151:         if (strpos($host, ':') !== false) {
152:             return false;
153:         }
154: 
155:         $parts['host'] = $host;
156: 
157:         if (isset($parts['path'])) {
158:             $path = strtolower($parts['path']);
159:             if (substr($path, 0, 1) != '/') {
160:                 return false;
161:             }
162:         } else {
163:             $path = '/';
164:         }
165: 
166:         $parts['path'] = $path;
167:         if (!isset($parts['port'])) {
168:             $parts['port'] = false;
169:         }
170: 
171: 
172:         $parts['unparsed'] = $trust_root;
173: 
174:         return $parts;
175:     }
176: 
177:     /**
178:      * Is this trust root sane?
179:      *
180:      * A trust root is sane if it is syntactically valid and it has a
181:      * reasonable domain name. Specifically, the domain name must be
182:      * more than one level below a standard TLD or more than two
183:      * levels below a two-letter tld.
184:      *
185:      * For example, '*.com' is not a sane trust root, but '*.foo.com'
186:      * is.  '*.co.uk' is not sane, but '*.bbc.co.uk' is.
187:      *
188:      * This check is not always correct, but it attempts to err on the
189:      * side of marking sane trust roots insane instead of marking
190:      * insane trust roots sane. For example, 'kink.fm' is marked as
191:      * insane even though it "should" (for some meaning of should) be
192:      * marked sane.
193:      *
194:      * This function should be used when creating OpenID servers to
195:      * alert the users of the server when a consumer attempts to get
196:      * the user to accept a suspicious trust root.
197:      *
198:      * @static
199:      * @param string $trust_root The trust root to check
200:      * @return bool $sanity Whether the trust root looks OK
201:      */
202:     static function isSane($trust_root)
203:     {
204:         $parts = Auth_OpenID_TrustRoot::_parse($trust_root);
205:         if ($parts === false) {
206:             return false;
207:         }
208: 
209:         // Localhost is a special case
210:         if ($parts['host'] == 'localhost') {
211:             return true;
212:         }
213:         
214:         $host_parts = explode('.', $parts['host']);
215:         if ($parts['wildcard']) {
216:             // Remove the empty string from the beginning of the array
217:             array_shift($host_parts);
218:         }
219: 
220:         if ($host_parts && !$host_parts[count($host_parts) - 1]) {
221:             array_pop($host_parts);
222:         }
223: 
224:         if (!$host_parts) {
225:             return false;
226:         }
227: 
228:         // Don't allow adjacent dots
229:         if (in_array('', $host_parts, true)) {
230:             return false;
231:         }
232: 
233:         // Get the top-level domain of the host. If it is not a valid TLD,
234:         // it's not sane.
235:         preg_match(Auth_OpenID___TLDs, $parts['host'], $matches);
236:         if (!$matches) {
237:             return false;
238:         }
239:         $tld = $matches[1];
240: 
241:         if (count($host_parts) == 1) {
242:             return false;
243:         }
244: 
245:         if ($parts['wildcard']) {
246:             // It's a 2-letter tld with a short second to last segment
247:             // so there needs to be more than two segments specified
248:             // (e.g. *.co.uk is insane)
249:             $second_level = $host_parts[count($host_parts) - 2];
250:             if (strlen($tld) == 2 && strlen($second_level) <= 3) {
251:                 return count($host_parts) > 2;
252:             }
253:         }
254: 
255:         return true;
256:     }
257: 
258:     /**
259:      * Does this URL match the given trust root?
260:      *
261:      * Return whether the URL falls under the given trust root. This
262:      * does not check whether the trust root is sane. If the URL or
263:      * trust root do not parse, this function will return false.
264:      *
265:      * @param string $trust_root The trust root to match against
266:      *
267:      * @param string $url The URL to check
268:      *
269:      * @return bool $matches Whether the URL matches against the
270:      * trust root
271:      */
272:     static function match($trust_root, $url)
273:     {
274:         $trust_root_parsed = Auth_OpenID_TrustRoot::_parse($trust_root);
275:         $url_parsed = Auth_OpenID_TrustRoot::_parse($url);
276:         if (!$trust_root_parsed || !$url_parsed) {
277:             return false;
278:         }
279: 
280:         // Check hosts matching
281:         if ($url_parsed['wildcard']) {
282:             return false;
283:         }
284:         if ($trust_root_parsed['wildcard']) {
285:             $host_tail = $trust_root_parsed['host'];
286:             $host = $url_parsed['host'];
287:             if ($host_tail &&
288:                 substr($host, -(strlen($host_tail))) != $host_tail &&
289:                 substr($host_tail, 1) != $host) {
290:                 return false;
291:             }
292:         } else {
293:             if ($trust_root_parsed['host'] != $url_parsed['host']) {
294:                 return false;
295:             }
296:         }
297: 
298:         // Check path and query matching
299:         $base_path = $trust_root_parsed['path'];
300:         $path = $url_parsed['path'];
301:         if (!isset($trust_root_parsed['query'])) {
302:             if ($base_path != $path) {
303:                 if (substr($path, 0, strlen($base_path)) != $base_path) {
304:                     return false;
305:                 }
306:                 if (substr($base_path, strlen($base_path) - 1, 1) != '/' &&
307:                     substr($path, strlen($base_path), 1) != '/') {
308:                     return false;
309:                 }
310:             }
311:         } else {
312:             $base_query = $trust_root_parsed['query'];
313:             $query = @$url_parsed['query'];
314:             $qplus = substr($query, 0, strlen($base_query) + 1);
315:             $bqplus = $base_query . '&';
316:             if ($base_path != $path ||
317:                 ($base_query != $query && $qplus != $bqplus)) {
318:                 return false;
319:             }
320:         }
321: 
322:         // The port and scheme need to match exactly
323:         return ($trust_root_parsed['scheme'] == $url_parsed['scheme'] &&
324:                 $url_parsed['port'] === $trust_root_parsed['port']);
325:     }
326: }
327: 
328: /*
329:  * If the endpoint is a relying party OpenID return_to endpoint,
330:  * return the endpoint URL. Otherwise, return None.
331:  *
332:  * This function is intended to be used as a filter for the Yadis
333:  * filtering interface.
334:  *
335:  * @see: C{L{openid.yadis.services}}
336:  * @see: C{L{openid.yadis.filters}}
337:  *
338:  * @param endpoint: An XRDS BasicServiceEndpoint, as returned by
339:  * performing Yadis dicovery.
340:  *
341:  * @returns: The endpoint URL or None if the endpoint is not a
342:  * relying party endpoint.
343:  */
344: function filter_extractReturnURL($endpoint)
345: {
346:     if ($endpoint->matchTypes(array(Auth_OpenID_RP_RETURN_TO_URL_TYPE))) {
347:         return $endpoint;
348:     } else {
349:         return null;
350:     }
351: }
352: 
353: function &Auth_OpenID_extractReturnURL(&$endpoint_list)
354: {
355:     $result = array();
356: 
357:     foreach ($endpoint_list as $endpoint) {
358:         if (filter_extractReturnURL($endpoint)) {
359:             $result[] = $endpoint;
360:         }
361:     }
362: 
363:     return $result;
364: }
365: 
366: /*
367:  * Is the return_to URL under one of the supplied allowed return_to
368:  * URLs?
369:  */
370: function Auth_OpenID_returnToMatches($allowed_return_to_urls, $return_to)
371: {
372:     foreach ($allowed_return_to_urls as $allowed_return_to) {
373:         // A return_to pattern works the same as a realm, except that
374:         // it's not allowed to use a wildcard. We'll model this by
375:         // parsing it as a realm, and not trying to match it if it has
376:         // a wildcard.
377: 
378:         $return_realm = Auth_OpenID_TrustRoot::_parse($allowed_return_to);
379:         if (// Parses as a trust root
380:             ($return_realm !== false) &&
381:             // Does not have a wildcard
382:             (!$return_realm['wildcard']) &&
383:             // Matches the return_to that we passed in with it
384:             (Auth_OpenID_TrustRoot::match($allowed_return_to, $return_to))) {
385:             return true;
386:         }
387:     }
388: 
389:     // No URL in the list matched
390:     return false;
391: }
392: 
393: /*
394:  * Given a relying party discovery URL return a list of return_to
395:  * URLs.
396:  */
397: function Auth_OpenID_getAllowedReturnURLs($relying_party_url, $fetcher,
398:               $discover_function=null)
399: {
400:     if ($discover_function === null) {
401:         $discover_function = array('Auth_Yadis_Yadis', 'discover');
402:     }
403: 
404:     $xrds_parse_cb = array('Auth_OpenID_ServiceEndpoint', 'consumerFromXRDS');
405: 
406:     list($rp_url_after_redirects, $endpoints) =
407:         Auth_Yadis_getServiceEndpoints($relying_party_url, $xrds_parse_cb,
408:                                        $discover_function, $fetcher);
409: 
410:     if ($rp_url_after_redirects != $relying_party_url) {
411:         // Verification caused a redirect
412:         return false;
413:     }
414: 
415:     call_user_func_array($discover_function,
416:                          array($relying_party_url, &$fetcher));
417: 
418:     $return_to_urls = array();
419:     $matching_endpoints = Auth_OpenID_extractReturnURL($endpoints);
420: 
421:     foreach ($matching_endpoints as $e) {
422:         $return_to_urls[] = $e->server_url;
423:     }
424: 
425:     return $return_to_urls;
426: }
427: 
428: /*
429:  * Verify that a return_to URL is valid for the given realm.
430:  *
431:  * This function builds a discovery URL, performs Yadis discovery on
432:  * it, makes sure that the URL does not redirect, parses out the
433:  * return_to URLs, and finally checks to see if the current return_to
434:  * URL matches the return_to.
435:  *
436:  * @return true if the return_to URL is valid for the realm
437:  */
438: function Auth_OpenID_verifyReturnTo($realm_str, $return_to, $fetcher,
439:               $_vrfy='Auth_OpenID_getAllowedReturnURLs')
440: {
441:     $disco_url = Auth_OpenID_TrustRoot::buildDiscoveryURL($realm_str);
442: 
443:     if ($disco_url === false) {
444:         return false;
445:     }
446: 
447:     $allowable_urls = call_user_func_array($_vrfy,
448:                            array($disco_url, $fetcher));
449: 
450:     // The realm_str could not be parsed.
451:     if ($allowable_urls === false) {
452:         return false;
453:     }
454: 
455:     if (Auth_OpenID_returnToMatches($allowable_urls, $return_to)) {
456:         return true;
457:     } else {
458:         return false;
459:     }
460: }
461: 
462: