1<?php 2 3/** 4 * auth.php 5 * 6 * Contains functions used to do authentication. 7 * 8 * @copyright 1999-2021 The SquirrelMail Project Team 9 * @license http://opensource.org/licenses/gpl-license.php GNU Public License 10 * @version $Id: auth.php 14887 2021-02-06 00:49:08Z pdontthink $ 11 * @package squirrelmail 12 */ 13 14/** Put in a safety net here, in case a naughty admin didn't run conf.pl when they upgraded */ 15 16if (! isset($smtp_auth_mech)) { 17 $smtp_auth_mech = 'none'; 18} 19 20if (! isset($imap_auth_mech)) { 21 $imap_auth_mech = 'login'; 22} 23 24if (! isset($use_imap_tls)) { 25 $use_imap_tls = false; 26} 27 28if (! isset($use_smtp_tls)) { 29 $use_smtp_tls = false; 30} 31 32/** 33 * Check if user has previously logged in to the SquirrelMail session. If user 34 * has not logged in, execution will stop inside this function. 35 * 36 * This function optionally checks the referrer of this page request. If the 37 * administrator wants to impose a check that the referrer of this page request 38 * is another page on the same domain (otherwise, the page request is likely 39 * the result of a XSS or phishing attack), then they need to specify the 40 * acceptable referrer domain in a variable named $check_referrer in 41 * config/config.php (or the configuration tool) for which the value is 42 * usually the same as the $domain setting (for example: 43 * $check_referrer = 'example.com'; 44 * However, in some cases (where proxy servers are in use, etc.), the 45 * acceptable referrer might be different. If $check_referrer is set to 46 * "###DOMAIN###", then the current value of $domain is used (useful in 47 * situations where $domain might change at runtime (when using the Login 48 * Manager plugin to host multiple domains with one SquirrelMail installation, 49 * for example)): 50 * $check_referrer = '###DOMAIN###'; 51 * NOTE HOWEVER, that referrer checks are not foolproof - they can be spoofed 52 * by browsers, and some browsers intentionally don't send them, in which 53 * case SquirrelMail silently ignores referrer checks. 54 * 55 * @return void This function returns ONLY if user has previously logged in 56 * successfully (otherwise, execution terminates herein). 57 */ 58function is_logged_in() { 59 60 // check for user login as well as referrer if needed 61 // 62 global $check_referrer, $domain; 63 if ($check_referrer == '###DOMAIN###') $check_referrer = $domain; 64 if (!empty($check_referrer)) { 65 $ssl_check_referrer = 'https://' . $check_referrer; 66 $plain_check_referrer = 'http://' . $check_referrer; 67 } 68 if (!sqgetGlobalVar('HTTP_REFERER', $referrer, SQ_SERVER)) $referrer = ''; 69 if (sqsession_is_registered('user_is_logged_in') 70 && (!$check_referrer || empty($referrer) 71 || ($check_referrer && !empty($referrer) 72 && (strpos(strtolower($referrer), strtolower($plain_check_referrer)) === 0 73 || strpos(strtolower($referrer), strtolower($ssl_check_referrer)) === 0)))) { 74 return; 75 } else { 76 77 global $session_expired_post, 78 $session_expired_location, $squirrelmail_language; 79 80 // use $message to indicate what logout text the user 81 // will see... if 0, typical "You must be logged in" 82 // if 1, information that the user session was saved 83 // and will be resumed after (re)login, if 2, there 84 // seems to have been a XSS or phishing attack (bad 85 // referrer) 86 // 87 $message = 0; 88 89 // First we store some information in the new session to prevent 90 // information-loss. 91 $session_expired_post = $_POST; 92 if (defined('PAGE_NAME')) { 93 $session_expired_location = PAGE_NAME; 94 } 95 96 if (!sqsession_is_registered('session_expired_post')) { 97 sqsession_register($session_expired_post,'session_expired_post'); 98 } 99 if (!sqsession_is_registered('session_expired_location')) { 100 sqsession_register($session_expired_location,'session_expired_location'); 101 if ($session_expired_location == 'compose') 102 $message = 1; 103 } 104 105 // was bad referrer the reason we were rejected? 106 // 107 if (sqsession_is_registered('user_is_logged_in') 108 && $check_referrer && !empty($referrer)) 109 $message = 2; 110 111 session_write_close(); 112 113 // signout page will deal with users who aren't logged 114 // in on its own; don't show error here 115 if (defined('PAGE_NAME') && PAGE_NAME == 'signout') { 116 return; 117 } 118 119 include_once( SM_PATH . 'functions/display_messages.php' ); 120 set_up_language($squirrelmail_language, true); 121 if (!$message) 122 logout_error( _("You must be logged in to access this page.") ); 123 else if ($message == 1) 124 logout_error( _("Your session has expired, but will be resumed after logging in again.") ); 125 else if ($message == 2) 126 logout_error( _("The current page request appears to have originated from an unrecognized source.") ); 127 exit; 128 } 129} 130 131/** 132 * Given the challenge from the server, supply the response using cram-md5 (See 133 * RFC 2195 for details) 134 * 135 * @param string $username User ID 136 * @param string $password User password supplied by User 137 * @param string $challenge The challenge supplied by the server 138 * @return string The response to be sent to the IMAP server 139 * 140 */ 141function cram_md5_response ($username,$password,$challenge) { 142 $challenge=base64_decode($challenge); 143 $hash=bin2hex(hmac_md5($challenge,$password)); 144 $response=base64_encode($username . " " . $hash) . "\r\n"; 145 return $response; 146} 147 148/** 149 * Return Digest-MD5 response. 150 * Given the challenge from the server, calculate and return the 151 * response-string for digest-md5 authentication. (See RFC 2831 for more 152 * details) 153 * 154 * @param string $username User ID 155 * @param string $password User password supplied by User 156 * @param string $challenge The challenge supplied by the server 157 * @param string $service The service name, usually 'imap'; it is used to 158 * define the digest-uri. 159 * @param string $host The host name, usually the server's FQDN; it is used to 160 * define the digest-uri. 161 * @param string $authz Authorization ID (since 1.4.23) 162 * @return string The response to be sent to the IMAP server 163 * @since 1.4.0 164 */ 165function digest_md5_response ($username,$password,$challenge,$service,$host,$authz='') { 166 $result=digest_md5_parse_challenge($challenge); 167 //FIXME we should check that $result contains the expected values that we use below 168 169 // verify server supports qop=auth 170 // $qop = explode(",",$result['qop']); 171 //if (!in_array("auth",$qop)) { 172 // rfc2831: client MUST fail if no qop methods supported 173 // return false; 174 //} 175 $cnonce = base64_encode(bin2hex(hmac_md5(microtime()))); 176 $ncount = "00000001"; 177 178 /* This can be auth (authentication only), auth-int (integrity protection), or 179 auth-conf (confidentiality protection). Right now only auth is supported. 180 DO NOT CHANGE THIS VALUE */ 181 $qop_value = "auth"; 182 183 $digest_uri_value = $service . '/' . $host; 184 185 // build the $response_value 186 //FIXME This will probably break badly if a server sends more than one realm 187 $string_a1 = utf8_encode($username).":"; 188 $string_a1 .= utf8_encode($result['realm']).":"; 189 $string_a1 .= utf8_encode($password); 190 $string_a1 = hmac_md5($string_a1); 191 $A1 = $string_a1 . ":" . $result['nonce'] . ":" . $cnonce; 192 if(!empty($authz)) { 193 $A1 .= ":" . utf8_encode($authz); 194 } 195 $A1 = bin2hex(hmac_md5($A1)); 196 $A2 = "AUTHENTICATE:$digest_uri_value"; 197 // If qop is auth-int or auth-conf, A2 gets a little extra 198 if ($qop_value != 'auth') { 199 $A2 .= ':00000000000000000000000000000000'; 200 } 201 $A2 = bin2hex(hmac_md5($A2)); 202 203 $string_response = $result['nonce'] . ':' . $ncount . ':' . $cnonce . ':' . $qop_value; 204 $response_value = bin2hex(hmac_md5($A1.":".$string_response.":".$A2)); 205 206 $reply = 'charset=utf-8,username="' . $username . '",realm="' . $result["realm"] . '",'; 207 $reply .= 'nonce="' . $result['nonce'] . '",nc=' . $ncount . ',cnonce="' . $cnonce . '",'; 208 $reply .= "digest-uri=\"$digest_uri_value\",response=$response_value"; 209 $reply .= ',qop=' . $qop_value; 210 if(!empty($authz)) { 211 $reply .= ',authzid=' . $authz; 212 } 213 $reply = base64_encode($reply); 214 return $reply . "\r\n"; 215 216} 217 218/** 219 * Parse Digest-MD5 challenge. 220 * This function parses the challenge sent during DIGEST-MD5 authentication and 221 * returns an array. See the RFC for details on what's in the challenge string. 222 * 223 * @param string $challenge Digest-MD5 Challenge 224 * @return array Digest-MD5 challenge decoded data 225 */ 226function digest_md5_parse_challenge($challenge) { 227 $challenge=base64_decode($challenge); 228 $parsed = array(); 229 while (!empty($challenge)) { 230 if ($challenge[0] == ',') { // First char is a comma, must not be 1st time through loop 231 $challenge=substr($challenge,1); 232 } 233 $key=explode('=',$challenge,2); 234 $challenge=$key[1]; 235 $key=$key[0]; 236 if ($challenge[0] == '"') { 237 // We're in a quoted value 238 // Drop the first quote, since we don't care about it 239 $challenge=substr($challenge,1); 240 // Now explode() to the next quote, which is the end of our value 241 $val=explode('"',$challenge,2); 242 $challenge=$val[1]; // The rest of the challenge, work on it in next iteration of loop 243 $value=explode(',',$val[0]); 244 // Now, for those quoted values that are only 1 piece.. 245 if (sizeof($value) == 1) { 246 $value=$value[0]; // Convert to non-array 247 } 248 } else { 249 // We're in a "simple" value - explode to next comma 250 $val=explode(',',$challenge,2); 251 if (isset($val[1])) { 252 $challenge=$val[1]; 253 } else { 254 unset($challenge); 255 } 256 $value=$val[0]; 257 } 258 $parsed["$key"]=$value; 259 } // End of while loop 260 return $parsed; 261} 262 263/** 264 * Creates a HMAC digest that can be used for auth purposes 265 * See RFCs 2104, 2617, 2831 266 * Uses mhash() extension if available 267 * 268 * @param string $data Data to apply hash function to. 269 * @param string $key Optional key, which, if supplied, will be used to 270 * calculate data's HMAC. 271 * @return string HMAC Digest string 272 */ 273function hmac_md5($data, $key='') { 274 if (extension_loaded('mhash')) { 275 if ($key== '') { 276 $mhash=mhash(MHASH_MD5,$data); 277 } else { 278 $mhash=mhash(MHASH_MD5,$data,$key); 279 } 280 return $mhash; 281 } 282 if (!$key) { 283 return pack('H*',md5($data)); 284 } 285 $key = str_pad($key,64,chr(0x00)); 286 if (strlen($key) > 64) { 287 $key = pack("H*",md5($key)); 288 } 289 $k_ipad = $key ^ str_repeat(chr(0x36), 64) ; 290 $k_opad = $key ^ str_repeat(chr(0x5c), 64) ; 291 /* Heh, let's get recursive. */ 292 $hmac=hmac_md5($k_opad . pack("H*",md5($k_ipad . $data)) ); 293 return $hmac; 294} 295 296/** 297 * Reads and decodes stored user password information 298 * 299 * Direct access to password information is deprecated. 300 * @return string password in plain text 301 * @since 1.4.11 302 */ 303function sqauth_read_password() { 304 global $is_login_verified_hook; 305 if ($is_login_verified_hook) global $key; 306 307 sqgetGlobalVar('key', $key, SQ_COOKIE); 308 sqgetGlobalVar('onetimepad', $onetimepad,SQ_SESSION); 309 310 return OneTimePadDecrypt($key, $onetimepad); 311} 312 313/** 314 * Saves or updates user password information 315 * 316 * This function is used to update the password information that 317 * SquirrelMail stores in the existing PHP session. It does NOT 318 * modify the password stored in the authentication system used 319 * by the IMAP server. 320 * 321 * This function must be called before any html output is started. 322 * Direct access to password information is deprecated. The saved 323 * password information is available only to the SquirrelMail script 324 * that is called/executed AFTER the current one. If your script 325 * needs access to the saved password after a sqauth_save_password() 326 * call, use the returned OTP encrypted key. 327 * 328 * @param string $pass password 329 * 330 * @return string Password encrypted with OTP. In case the script 331 * wants to access the password information before 332 * the end of its execution. 333 * 334 * @since 1.4.16 335 * 336 */ 337function sqauth_save_password($pass) { 338 sqgetGlobalVar('base_uri', $base_uri, SQ_SESSION); 339 340 $onetimepad = OneTimePadCreate(strlen($pass)); 341 sqsession_register($onetimepad,'onetimepad'); 342 $key = OneTimePadEncrypt($pass, $onetimepad); 343 sqsetcookie('key', $key, false, $base_uri); 344 return $key; 345} 346 347/** 348 * Fillin user and password based on SMTP auth settings. 349 * 350 * @param string $user Reference to SMTP username 351 * @param string $pass Reference to SMTP password (unencrypted) 352 * @since 1.4.11 353 */ 354function get_smtp_user(&$user, &$pass) { 355 global $username, $smtp_auth_mech, 356 $smtp_sitewide_user, $smtp_sitewide_pass; 357 358 if ($smtp_auth_mech == 'none') { 359 $user = ''; 360 $pass = ''; 361 } elseif ( isset($smtp_sitewide_user) && isset($smtp_sitewide_pass) && 362 !empty($smtp_sitewide_user)) { 363 $user = $smtp_sitewide_user; 364 $pass = $smtp_sitewide_pass; 365 } else { 366 $user = $username; 367 $pass = sqauth_read_password(); 368 } 369 370 // plugin authors note: override $user or $pass by 371 // returning an array where the new username is the 372 // first array value and the new password is the 373 // second array value e.g., return array($myuser, $mypass); 374 // 375 // NOTE: there is another hook in class/deliver/Deliver_SMTP.class.php 376 // called "smtp_authenticate" that allows a plugin to run its own 377 // custom authentication routine - this hook here is thus slightly 378 // mis-named but is too old to change. Be careful that you do not 379 // confuse your hook names. 380 // 381 $ret = do_hook_function('smtp_auth', array($user, $pass)); 382 if (!empty($ret[0])) 383 $user = $ret[0]; 384 if (!empty($ret[1])) 385 $pass = $ret[1]; 386} 387 388