5304458e6120d0f36bbf3856a235cae950ce6ba7
[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 1999-2010 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 sqgetGlobalVar('key', $key, SQ_COOKIE);
97 sqgetGlobalVar('onetimepad', $onetimepad,SQ_SESSION);
98
99 return OneTimePadDecrypt($key, $onetimepad);
100 }
101
102 /**
103 * Saves or updates user password information
104 *
105 * This function is used to update the password information that
106 * SquirrelMail stores in the existing PHP session. It does NOT
107 * modify the password stored in the authentication system used
108 * by the IMAP server.
109 *
110 * This function must be called before any html output is started.
111 * Direct access to password information is deprecated. The saved
112 * password information is available only to the SquirrelMail script
113 * that is called/executed AFTER the current one. If your script
114 * needs access to the saved password after a sqauth_save_password()
115 * call, use the returned OTP encrypted key.
116 *
117 * @param string $pass password
118 *
119 * @return string Password encrypted with OTP. In case the script
120 * wants to access the password information before
121 * the end of its execution.
122 *
123 * @since 1.5.1
124 *
125 */
126 function sqauth_save_password($pass) {
127 sqgetGlobalVar('base_uri', $base_uri, SQ_SESSION);
128
129 $onetimepad = OneTimePadCreate(strlen($pass));
130 sqsession_register($onetimepad,'onetimepad');
131 $key = OneTimePadEncrypt($pass, $onetimepad);
132 sqsetcookie('key', $key, false, $base_uri);
133 return $key;
134 }
135
136 /**
137 * Given the challenge from the server, supply the response using cram-md5 (See
138 * RFC 2195 for details)
139 *
140 * @param string $username User ID
141 * @param string $password User password supplied by User
142 * @param string $challenge The challenge supplied by the server
143 * @return string The response to be sent to the IMAP server
144 * @since 1.4.0
145 */
146 function cram_md5_response ($username,$password,$challenge) {
147 $challenge=base64_decode($challenge);
148 $hash=bin2hex(hmac_md5($challenge,$password));
149 $response=base64_encode($username . " " . $hash) . "\r\n";
150 return $response;
151 }
152
153 /**
154 * Return Digest-MD5 response.
155 * Given the challenge from the server, calculate and return the
156 * response-string for digest-md5 authentication. (See RFC 2831 for more
157 * details)
158 *
159 * @param string $username User ID
160 * @param string $password User password supplied by User
161 * @param string $challenge The challenge supplied by the server
162 * @param string $service The service name, usually 'imap'; it is used to
163 * define the digest-uri.
164 * @param string $host The host name, usually the server's FQDN; it is used to
165 * define the digest-uri.
166 * @param string $authz Authorization ID (since 1.5.2)
167 * @return string The response to be sent to the IMAP server
168 * @since 1.4.0
169 */
170 function digest_md5_response ($username,$password,$challenge,$service,$host,$authz='') {
171 $result=digest_md5_parse_challenge($challenge);
172 //FIXME we should check that $result contains the expected values that we use below
173
174 // verify server supports qop=auth
175 // $qop = explode(",",$result['qop']);
176 //if (!in_array("auth",$qop)) {
177 // rfc2831: client MUST fail if no qop methods supported
178 // return false;
179 //}
180 $cnonce = base64_encode(bin2hex(hmac_md5(microtime())));
181 $ncount = "00000001";
182
183 /* This can be auth (authentication only), auth-int (integrity protection), or
184 auth-conf (confidentiality protection). Right now only auth is supported.
185 DO NOT CHANGE THIS VALUE */
186 $qop_value = "auth";
187
188 $digest_uri_value = $service . '/' . $host;
189
190 // build the $response_value
191 //FIXME This will probably break badly if a server sends more than one realm
192 $string_a1 = utf8_encode($username).":";
193 $string_a1 .= utf8_encode($result['realm']).":";
194 $string_a1 .= utf8_encode($password);
195 $string_a1 = hmac_md5($string_a1);
196 $A1 = $string_a1 . ":" . $result['nonce'] . ":" . $cnonce;
197 if(!empty($authz)) {
198 $A1 .= ":" . utf8_encode($authz);
199 }
200 $A1 = bin2hex(hmac_md5($A1));
201 $A2 = "AUTHENTICATE:$digest_uri_value";
202 // If qop is auth-int or auth-conf, A2 gets a little extra
203 if ($qop_value != 'auth') {
204 $A2 .= ':00000000000000000000000000000000';
205 }
206 $A2 = bin2hex(hmac_md5($A2));
207
208 $string_response = $result['nonce'] . ':' . $ncount . ':' . $cnonce . ':' . $qop_value;
209 $response_value = bin2hex(hmac_md5($A1.":".$string_response.":".$A2));
210
211 $reply = 'charset=utf-8,username="' . $username . '",realm="' . $result["realm"] . '",';
212 $reply .= 'nonce="' . $result['nonce'] . '",nc=' . $ncount . ',cnonce="' . $cnonce . '",';
213 $reply .= "digest-uri=\"$digest_uri_value\",response=$response_value";
214 $reply .= ',qop=' . $qop_value;
215 if(!empty($authz)) {
216 $reply .= ',authzid=' . $authz;
217 }
218 $reply = base64_encode($reply);
219 return $reply . "\r\n";
220
221 }
222
223 /**
224 * Parse Digest-MD5 challenge.
225 * This function parses the challenge sent during DIGEST-MD5 authentication and
226 * returns an array. See the RFC for details on what's in the challenge string.
227 *
228 * @param string $challenge Digest-MD5 Challenge
229 * @return array Digest-MD5 challenge decoded data
230 * @since 1.4.0
231 */
232 function digest_md5_parse_challenge($challenge) {
233 $challenge=base64_decode($challenge);
234 $parsed = array();
235 while (!empty($challenge)) {
236 if ($challenge{0} == ',') { // First char is a comma, must not be 1st time through loop
237 $challenge=substr($challenge,1);
238 }
239 $key=explode('=',$challenge,2);
240 $challenge=$key[1];
241 $key=$key[0];
242 if ($challenge{0} == '"') {
243 // We're in a quoted value
244 // Drop the first quote, since we don't care about it
245 $challenge=substr($challenge,1);
246 // Now explode() to the next quote, which is the end of our value
247 $val=explode('"',$challenge,2);
248 $challenge=$val[1]; // The rest of the challenge, work on it in next iteration of loop
249 $value=explode(',',$val[0]);
250 // Now, for those quoted values that are only 1 piece..
251 if (sizeof($value) == 1) {
252 $value=$value[0]; // Convert to non-array
253 }
254 } else {
255 // We're in a "simple" value - explode to next comma
256 $val=explode(',',$challenge,2);
257 if (isset($val[1])) {
258 $challenge=$val[1];
259 } else {
260 unset($challenge);
261 }
262 $value=$val[0];
263 }
264 $parsed["$key"]=$value;
265 } // End of while loop
266 return $parsed;
267 }
268
269 /**
270 * Creates a HMAC digest that can be used for auth purposes
271 * See RFCs 2104, 2617, 2831
272 * Uses mhash() extension if available
273 *
274 * @param string $data Data to apply hash function to.
275 * @param string $key Optional key, which, if supplied, will be used to
276 * calculate data's HMAC.
277 * @return string HMAC Digest string
278 * @since 1.4.0
279 */
280 function hmac_md5($data, $key='') {
281 if (extension_loaded('mhash')) {
282 if ($key== '') {
283 $mhash=mhash(MHASH_MD5,$data);
284 } else {
285 $mhash=mhash(MHASH_MD5,$data,$key);
286 }
287 return $mhash;
288 }
289 if (!$key) {
290 return pack('H*',md5($data));
291 }
292 $key = str_pad($key,64,chr(0x00));
293 if (strlen($key) > 64) {
294 $key = pack("H*",md5($key));
295 }
296 $k_ipad = $key ^ str_repeat(chr(0x36), 64) ;
297 $k_opad = $key ^ str_repeat(chr(0x5c), 64) ;
298 /* Heh, let's get recursive. */
299 $hmac=hmac_md5($k_opad . pack("H*",md5($k_ipad . $data)) );
300 return $hmac;
301 }
302
303 /**
304 * Fillin user and password based on SMTP auth settings.
305 *
306 * @param string $user Reference to SMTP username
307 * @param string $pass Reference to SMTP password (unencrypted)
308 * @since 1.4.11
309 */
310 function get_smtp_user(&$user, &$pass) {
311 global $username, $smtp_auth_mech,
312 $smtp_sitewide_user, $smtp_sitewide_pass;
313
314 if ($smtp_auth_mech == 'none') {
315 $user = '';
316 $pass = '';
317 } elseif ( isset($smtp_sitewide_user) && isset($smtp_sitewide_pass) &&
318 !empty($smtp_sitewide_user)) {
319 $user = $smtp_sitewide_user;
320 $pass = $smtp_sitewide_pass;
321 } else {
322 $user = $username;
323 $pass = sqauth_read_password();
324 }
325
326 // plugin authors note: override $user or $pass by
327 // directly changing the arguments array contents
328 // in your plugin e.g., $args[0] = 'new_username';
329 //
330 $temp = array(&$user, &$pass);
331 do_hook('smtp_auth', $temp);
332 }