Fix hook name clash: new smtp_auth hook added recently (a few months ago) has been...
[squirrelmail.git] / functions / auth.php
1 <?php
2
3 /**
4 * auth.php
5 *
6 * Contains functions used to do authentication.
7 *
8 * Dependencies:
9 * functions/global.php
10 * functions/strings.php.
11 *
12 * @copyright 1999-2011 The SquirrelMail Project Team
13 * @license http://opensource.org/licenses/gpl-license.php GNU Public License
14 * @version $Id$
15 * @package squirrelmail
16 */
17
18
19 /**
20 * Detect whether user is logged in
21 *
22 * Function is similar to is_logged_in() function. If user is logged in, function
23 * returns true. If user is not logged in or session is expired, function saves $_POST
24 * and PAGE_NAME in session and returns false. POST information is saved in
25 * 'session_expired_post' variable, PAGE_NAME is saved in 'session_expired_location'.
26 *
27 * This function optionally checks the referrer of this page request. If the
28 * administrator wants to impose a check that the referrer of this page request
29 * is another page on the same domain (otherwise, the page request is likely
30 * the result of a XSS or phishing attack), then they need to specify the
31 * acceptable referrer domain in a variable named $check_referrer in
32 * config/config.php (or the configuration tool) for which the value is
33 * usually the same as the $domain setting (for example:
34 * $check_referrer = 'example.com';
35 * However, in some cases (where proxy servers are in use, etc.), the
36 * acceptable referrer might be different. If $check_referrer is set to
37 * "###DOMAIN###", then the current value of $domain is used (useful in
38 * situations where $domain might change at runtime (when using the Login
39 * Manager plugin to host multiple domains with one SquirrelMail installation,
40 * for example)):
41 * $check_referrer = '###DOMAIN###';
42 * NOTE HOWEVER, that referrer checks are not foolproof - they can be spoofed
43 * by browsers, and some browsers intentionally don't send them, in which
44 * case SquirrelMail silently ignores referrer checks.
45 *
46 * Script that uses this function instead of is_logged_in() function, must handle user
47 * level messages.
48 * @return boolean
49 * @since 1.5.1
50 */
51 function sqauth_is_logged_in() {
52
53 global $check_referrer, $domain;
54 if (!sqgetGlobalVar('HTTP_REFERER', $referrer, SQ_SERVER)) $referrer = '';
55 if ($check_referrer == '###DOMAIN###') $check_referrer = $domain;
56 if (!empty($check_referrer)) {
57 $ssl_check_referrer = 'https://' . $check_referrer;
58 $plain_check_referrer = 'http://' . $check_referrer;
59 }
60 if (sqsession_is_registered('user_is_logged_in')
61 && (!$check_referrer || empty($referrer)
62 || ($check_referrer && !empty($referrer)
63 && (strpos(strtolower($referrer), strtolower($plain_check_referrer)) === 0
64 || strpos(strtolower($referrer), strtolower($ssl_check_referrer)) === 0)))) {
65 return true;
66 }
67
68 // First we store some information in the new session to prevent
69 // information-loss.
70 $session_expired_post = $_POST;
71 if (defined('PAGE_NAME'))
72 $session_expired_location = PAGE_NAME;
73 else
74 $session_expired_location = '';
75
76 if (!sqsession_is_registered('session_expired_post')) {
77 sqsession_register($session_expired_post,'session_expired_post');
78 }
79 if (!sqsession_is_registered('session_expired_location')) {
80 sqsession_register($session_expired_location,'session_expired_location');
81 }
82
83 session_write_close();
84
85 return false;
86 }
87
88 /**
89 * Reads and decodes stored user password information
90 *
91 * Direct access to password information is deprecated.
92 * @return string password in plain text
93 * @since 1.5.1
94 */
95 function sqauth_read_password() {
96 global $currentHookName;
97 if ($currentHookName == 'login_verified') global $key;
98
99 sqgetGlobalVar('key', $key, SQ_COOKIE);
100 sqgetGlobalVar('onetimepad', $onetimepad,SQ_SESSION);
101
102 return OneTimePadDecrypt($key, $onetimepad);
103 }
104
105 /**
106 * Saves or updates user password information
107 *
108 * This function is used to update the password information that
109 * SquirrelMail stores in the existing PHP session. It does NOT
110 * modify the password stored in the authentication system used
111 * by the IMAP server.
112 *
113 * This function must be called before any html output is started.
114 * Direct access to password information is deprecated. The saved
115 * password information is available only to the SquirrelMail script
116 * that is called/executed AFTER the current one. If your script
117 * needs access to the saved password after a sqauth_save_password()
118 * call, use the returned OTP encrypted key.
119 *
120 * @param string $pass password
121 *
122 * @return string Password encrypted with OTP. In case the script
123 * wants to access the password information before
124 * the end of its execution.
125 *
126 * @since 1.5.1
127 *
128 */
129 function sqauth_save_password($pass) {
130 sqgetGlobalVar('base_uri', $base_uri, SQ_SESSION);
131
132 $onetimepad = OneTimePadCreate(strlen($pass));
133 sqsession_register($onetimepad,'onetimepad');
134 $key = OneTimePadEncrypt($pass, $onetimepad);
135 sqsetcookie('key', $key, false, $base_uri);
136 return $key;
137 }
138
139 /**
140 * Given the challenge from the server, supply the response using cram-md5 (See
141 * RFC 2195 for details)
142 *
143 * @param string $username User ID
144 * @param string $password User password supplied by User
145 * @param string $challenge The challenge supplied by the server
146 * @return string The response to be sent to the IMAP server
147 * @since 1.4.0
148 */
149 function cram_md5_response ($username,$password,$challenge) {
150 $challenge=base64_decode($challenge);
151 $hash=bin2hex(hmac_md5($challenge,$password));
152 $response=base64_encode($username . " " . $hash) . "\r\n";
153 return $response;
154 }
155
156 /**
157 * Return Digest-MD5 response.
158 * Given the challenge from the server, calculate and return the
159 * response-string for digest-md5 authentication. (See RFC 2831 for more
160 * details)
161 *
162 * @param string $username User ID
163 * @param string $password User password supplied by User
164 * @param string $challenge The challenge supplied by the server
165 * @param string $service The service name, usually 'imap'; it is used to
166 * define the digest-uri.
167 * @param string $host The host name, usually the server's FQDN; it is used to
168 * define the digest-uri.
169 * @param string $authz Authorization ID (since 1.5.2)
170 * @return string The response to be sent to the IMAP server
171 * @since 1.4.0
172 */
173 function digest_md5_response ($username,$password,$challenge,$service,$host,$authz='') {
174 $result=digest_md5_parse_challenge($challenge);
175 //FIXME we should check that $result contains the expected values that we use below
176
177 // verify server supports qop=auth
178 // $qop = explode(",",$result['qop']);
179 //if (!in_array("auth",$qop)) {
180 // rfc2831: client MUST fail if no qop methods supported
181 // return false;
182 //}
183 $cnonce = base64_encode(bin2hex(hmac_md5(microtime())));
184 $ncount = "00000001";
185
186 /* This can be auth (authentication only), auth-int (integrity protection), or
187 auth-conf (confidentiality protection). Right now only auth is supported.
188 DO NOT CHANGE THIS VALUE */
189 $qop_value = "auth";
190
191 $digest_uri_value = $service . '/' . $host;
192
193 // build the $response_value
194 //FIXME This will probably break badly if a server sends more than one realm
195 $string_a1 = utf8_encode($username).":";
196 $string_a1 .= utf8_encode($result['realm']).":";
197 $string_a1 .= utf8_encode($password);
198 $string_a1 = hmac_md5($string_a1);
199 $A1 = $string_a1 . ":" . $result['nonce'] . ":" . $cnonce;
200 if(!empty($authz)) {
201 $A1 .= ":" . utf8_encode($authz);
202 }
203 $A1 = bin2hex(hmac_md5($A1));
204 $A2 = "AUTHENTICATE:$digest_uri_value";
205 // If qop is auth-int or auth-conf, A2 gets a little extra
206 if ($qop_value != 'auth') {
207 $A2 .= ':00000000000000000000000000000000';
208 }
209 $A2 = bin2hex(hmac_md5($A2));
210
211 $string_response = $result['nonce'] . ':' . $ncount . ':' . $cnonce . ':' . $qop_value;
212 $response_value = bin2hex(hmac_md5($A1.":".$string_response.":".$A2));
213
214 $reply = 'charset=utf-8,username="' . $username . '",realm="' . $result["realm"] . '",';
215 $reply .= 'nonce="' . $result['nonce'] . '",nc=' . $ncount . ',cnonce="' . $cnonce . '",';
216 $reply .= "digest-uri=\"$digest_uri_value\",response=$response_value";
217 $reply .= ',qop=' . $qop_value;
218 if(!empty($authz)) {
219 $reply .= ',authzid=' . $authz;
220 }
221 $reply = base64_encode($reply);
222 return $reply . "\r\n";
223
224 }
225
226 /**
227 * Parse Digest-MD5 challenge.
228 * This function parses the challenge sent during DIGEST-MD5 authentication and
229 * returns an array. See the RFC for details on what's in the challenge string.
230 *
231 * @param string $challenge Digest-MD5 Challenge
232 * @return array Digest-MD5 challenge decoded data
233 * @since 1.4.0
234 */
235 function digest_md5_parse_challenge($challenge) {
236 $challenge=base64_decode($challenge);
237 $parsed = array();
238 while (!empty($challenge)) {
239 if ($challenge{0} == ',') { // First char is a comma, must not be 1st time through loop
240 $challenge=substr($challenge,1);
241 }
242 $key=explode('=',$challenge,2);
243 $challenge=$key[1];
244 $key=$key[0];
245 if ($challenge{0} == '"') {
246 // We're in a quoted value
247 // Drop the first quote, since we don't care about it
248 $challenge=substr($challenge,1);
249 // Now explode() to the next quote, which is the end of our value
250 $val=explode('"',$challenge,2);
251 $challenge=$val[1]; // The rest of the challenge, work on it in next iteration of loop
252 $value=explode(',',$val[0]);
253 // Now, for those quoted values that are only 1 piece..
254 if (sizeof($value) == 1) {
255 $value=$value[0]; // Convert to non-array
256 }
257 } else {
258 // We're in a "simple" value - explode to next comma
259 $val=explode(',',$challenge,2);
260 if (isset($val[1])) {
261 $challenge=$val[1];
262 } else {
263 unset($challenge);
264 }
265 $value=$val[0];
266 }
267 $parsed["$key"]=$value;
268 } // End of while loop
269 return $parsed;
270 }
271
272 /**
273 * Creates a HMAC digest that can be used for authentication purposes
274 * See RFCs 2104, 2617, 2831
275 *
276 * Uses PHP's Hash extension if available (enabled by default in PHP
277 * 5.1.2+ - see http://www.php.net/manual/en/hash.requirements.php
278 * or, if installed on earlier PHP versions, the PECL hash module -
279 * see http://pecl.php.net/package/hash
280 *
281 * Otherwise, will attempt to use the Mhash extension - see
282 * http://www.php.net/manual/en/mhash.requirements.php
283 *
284 * Finally, a fall-back custom implementation is used if none of
285 * the above are available.
286 *
287 * @param string $data The data to be encoded/hashed
288 * @param string $key The (shared) secret key that will be used
289 * to build the keyed hash. This argument is
290 * technically optional, but only for internal
291 * use (when the custom hash implementation is
292 * being used) - external callers should always
293 * specify a value for this argument.
294 *
295 * @return string The HMAC-MD5 digest string
296 * @since 1.4.0
297 *
298 */
299 function hmac_md5($data, $key='') {
300
301 // use PHP's native Hash extension if possible
302 //
303 if (function_exists('hash_hmac'))
304 return pack('H*', hash_hmac('md5', $data, $key));
305
306
307 // otherwise, use (obsolete) mhash extension if available
308 //
309 if (extension_loaded('mhash')) {
310
311 if ($key == '')
312 $mhash = mhash(MHASH_MD5, $data);
313 else
314 $mhash = mhash(MHASH_MD5, $data, $key);
315
316 return $mhash;
317 }
318
319
320 // or, our own implementation...
321 //
322 if (!$key)
323 return pack('H*', md5($data));
324
325 $key = str_pad($key, 64, chr(0x00));
326
327 if (strlen($key) > 64)
328 $key = pack("H*", md5($key));
329
330 $k_ipad = $key ^ str_repeat(chr(0x36), 64);
331 $k_opad = $key ^ str_repeat(chr(0x5c), 64);
332
333 $hmac = hmac_md5($k_opad . pack('H*', md5($k_ipad . $data)));
334
335 return $hmac;
336
337 }
338
339 /**
340 * Fillin user and password based on SMTP auth settings.
341 *
342 * @param string $user Reference to SMTP username
343 * @param string $pass Reference to SMTP password (unencrypted)
344 * @since 1.4.11
345 */
346 function get_smtp_user(&$user, &$pass) {
347 global $username, $smtp_auth_mech,
348 $smtp_sitewide_user, $smtp_sitewide_pass;
349
350 if ($smtp_auth_mech == 'none') {
351 $user = '';
352 $pass = '';
353 } elseif ( isset($smtp_sitewide_user) && isset($smtp_sitewide_pass) &&
354 !empty($smtp_sitewide_user)) {
355 $user = $smtp_sitewide_user;
356 $pass = $smtp_sitewide_pass;
357 } else {
358 $user = $username;
359 $pass = sqauth_read_password();
360 }
361
362 // plugin authors note: override $user or $pass by
363 // directly changing the arguments array contents
364 // in your plugin e.g., $args[0] = 'new_username';
365 //
366 // NOTE: there is another hook in class/deliver/Deliver_SMTP.class.php
367 // called "smtp_authenticate" that allows a plugin to run its own
368 // custom authentication routine - this hook here is thus slightly
369 // mis-named but is too old to change. Be careful that you do not
370 // confuse your hook names.
371 //
372 $temp = array(&$user, &$pass);
373 do_hook('smtp_auth', $temp);
374 }