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 &copy; 1999-2007 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  * Script that uses this function instead of is_logged_in() function, must handle user
  28  * level messages.
  29  * @return boolean
  30  * @since 1.5.1
  31  */
  32 function sqauth_is_logged_in() {
  33     if ( sqsession_is_registered('user_is_logged_in') ) {
  34         return true;
  35     }
  36
  37     //  First we store some information in the new session to prevent
  38     //  information-loss.
  39     $session_expired_post = $_POST;
  40     if (defined('PAGE_NAME'))
  41         $session_expired_location = PAGE_NAME;
  42     else
  43         $session_expired_location = '';
  44
  45     if (!sqsession_is_registered('session_expired_post')) {
  46         sqsession_register($session_expired_post,'session_expired_post');
  47     }
  48     if (!sqsession_is_registered('session_expired_location')) {
  49         sqsession_register($session_expired_location,'session_expired_location');
  50     }
  51
  52     session_write_close();
  53
  54     return false;
  55 }
  56
  57 /**
  58  * Reads and decodes stored user password information
  59  *
  60  * Direct access to password information is deprecated.
  61  * @return string password in plain text
  62  * @since 1.5.1
  63  */
  64 function sqauth_read_password() {
  65     sqgetGlobalVar('key',         $key,       SQ_COOKIE);
  66     sqgetGlobalVar('onetimepad',  $onetimepad,SQ_SESSION);
  67
  68     return OneTimePadDecrypt($key, $onetimepad);
  69 }
  70
  71 /**
  72  * Saves or updates user password information
  73  *
  74  * This function is used to update the password information that
  75  * SquirrelMail stores in the existing PHP session. It does NOT
  76  * modify the password stored in the authentication system used
  77  * by the IMAP server.
  78  *
  79  * This function must be called before any html output is started.
  80  * Direct access to password information is deprecated. The saved
  81  * password information is available only to the SquirrelMail script
  82  * that is called/executed AFTER the current one. If your script
  83  * needs access to the saved password after a sqauth_save_password()
  84  * call, use the returned OTP encrypted key.
  85  *
  86  * @param string $pass password
  87  *
  88  * @return string Password encrypted with OTP. In case the script
  89  *                wants to access the password information before
  90  *                the end of its execution.
  91  *
  92  * @since 1.5.1
  93  *
  94  */
  95 function sqauth_save_password($pass) {
  96     sqgetGlobalVar('base_uri',    $base_uri,   SQ_SESSION);
  97
  98     $onetimepad = OneTimePadCreate(strlen($pass));
  99     sqsession_register($onetimepad,'onetimepad');
 100     $key = OneTimePadEncrypt($pass, $onetimepad);
 101     sqsetcookie('key', $key, false, $base_uri);
 102     return $key;
 103 }
 104
 105 /**
 106  * Given the challenge from the server, supply the response using cram-md5 (See
 107  * RFC 2195 for details)
 108  *
 109  * @param string $username User ID
 110  * @param string $password User password supplied by User
 111  * @param string $challenge The challenge supplied by the server
 112  * @return string The response to be sent to the IMAP server
 113  * @since 1.4.0
 114  */
 115 function cram_md5_response ($username,$password,$challenge) {
 116     $challenge=base64_decode($challenge);
 117     $hash=bin2hex(hmac_md5($challenge,$password));
 118     $response=base64_encode($username . " " . $hash) . "\r\n";
 119     return $response;
 120 }
 121
 122 /**
 123  * Return Digest-MD5 response.
 124  * Given the challenge from the server, calculate and return the
 125  * response-string for digest-md5 authentication.  (See RFC 2831 for more
 126  * details)
 127  *
 128  * @param string $username User ID
 129  * @param string $password User password supplied by User
 130  * @param string $challenge The challenge supplied by the server
 131  * @param string $service The service name, usually 'imap'; it is used to
 132  *   define the digest-uri.
 133  * @param string $host The host name, usually the server's FQDN; it is used to
 134  *   define the digest-uri.
 135  * @param string $authz Authorization ID (since 1.5.2)
 136  * @return string The response to be sent to the IMAP server
 137  * @since 1.4.0
 138  */
 139 function digest_md5_response ($username,$password,$challenge,$service,$host,$authz='') {
 140     $result=digest_md5_parse_challenge($challenge);
 141     //FIXME we should check that $result contains the expected values that we use below
 142
 143     // verify server supports qop=auth
 144     // $qop = explode(",",$result['qop']);
 145     //if (!in_array("auth",$qop)) {
 146     // rfc2831: client MUST fail if no qop methods supported
 147     // return false;
 148     //}
 149     $cnonce = base64_encode(bin2hex(hmac_md5(microtime())));
 150     $ncount = "00000001";
 151
 152     /* This can be auth (authentication only), auth-int (integrity protection), or
 153        auth-conf (confidentiality protection).  Right now only auth is supported.
 154        DO NOT CHANGE THIS VALUE */
 155     $qop_value = "auth";
 156
 157     $digest_uri_value = $service . '/' . $host;
 158
 159     // build the $response_value
 160     //FIXME This will probably break badly if a server sends more than one realm
 161     $string_a1 = utf8_encode($username).":";
 162     $string_a1 .= utf8_encode($result['realm']).":";
 163     $string_a1 .= utf8_encode($password);
 164     $string_a1 = hmac_md5($string_a1);
 165     $A1 = $string_a1 . ":" . $result['nonce'] . ":" . $cnonce;
 166     if(!empty($authz)) {
 167         $A1 .= ":" . utf8_encode($authz);
 168     }
 169     $A1 = bin2hex(hmac_md5($A1));
 170     $A2 = "AUTHENTICATE:$digest_uri_value";
 171     // If qop is auth-int or auth-conf, A2 gets a little extra
 172     if ($qop_value != 'auth') {
 173         $A2 .= ':00000000000000000000000000000000';
 174     }
 175     $A2 = bin2hex(hmac_md5($A2));
 176
 177     $string_response = $result['nonce'] . ':' . $ncount . ':' . $cnonce . ':' . $qop_value;
 178     $response_value = bin2hex(hmac_md5($A1.":".$string_response.":".$A2));
 179
 180     $reply = 'charset=utf-8,username="' . $username . '",realm="' . $result["realm"] . '",';
 181     $reply .= 'nonce="' . $result['nonce'] . '",nc=' . $ncount . ',cnonce="' . $cnonce . '",';
 182     $reply .= "digest-uri=\"$digest_uri_value\",response=$response_value";
 183     $reply .= ',qop=' . $qop_value;
 184     if(!empty($authz)) {
 185         $reply .= ',authzid=' . $authz;
 186     }
 187     $reply = base64_encode($reply);
 188     return $reply . "\r\n";
 189
 190 }
 191
 192 /**
 193  * Parse Digest-MD5 challenge.
 194  * This function parses the challenge sent during DIGEST-MD5 authentication and
 195  * returns an array. See the RFC for details on what's in the challenge string.
 196  *
 197  * @param string $challenge Digest-MD5 Challenge
 198  * @return array Digest-MD5 challenge decoded data
 199  * @since 1.4.0
 200  */
 201 function digest_md5_parse_challenge($challenge) {
 202     $challenge=base64_decode($challenge);
 203     $parsed = array();
 204     while (!empty($challenge)) {
 205         if ($challenge{0} == ',') { // First char is a comma, must not be 1st time through loop
 206             $challenge=substr($challenge,1);
 207         }
 208         $key=explode('=',$challenge,2);
 209         $challenge=$key[1];
 210         $key=$key[0];
 211         if ($challenge{0} == '"') {
 212             // We're in a quoted value
 213             // Drop the first quote, since we don't care about it
 214             $challenge=substr($challenge,1);
 215             // Now explode() to the next quote, which is the end of our value
 216             $val=explode('"',$challenge,2);
 217             $challenge=$val[1]; // The rest of the challenge, work on it in next iteration of loop
 218             $value=explode(',',$val[0]);
 219             // Now, for those quoted values that are only 1 piece..
 220             if (sizeof($value) == 1) {
 221                 $value=$value[0];  // Convert to non-array
 222             }
 223         } else {
 224             // We're in a "simple" value - explode to next comma
 225             $val=explode(',',$challenge,2);
 226             if (isset($val[1])) {
 227                 $challenge=$val[1];
 228             } else {
 229                 unset($challenge);
 230             }
 231             $value=$val[0];
 232         }
 233         $parsed["$key"]=$value;
 234     } // End of while loop
 235     return $parsed;
 236 }
 237
 238 /**
 239  * Creates a HMAC digest that can be used for auth purposes
 240  * See RFCs 2104, 2617, 2831
 241  * Uses mhash() extension if available
 242  *
 243  * @param string $data Data to apply hash function to.
 244  * @param string $key Optional key, which, if supplied, will be used to
 245  * calculate data's HMAC.
 246  * @return string HMAC Digest string
 247  * @since 1.4.0
 248  */
 249 function hmac_md5($data, $key='') {
 250     if (extension_loaded('mhash')) {
 251         if ($key== '') {
 252             $mhash=mhash(MHASH_MD5,$data);
 253         } else {
 254             $mhash=mhash(MHASH_MD5,$data,$key);
 255         }
 256         return $mhash;
 257     }
 258     if (!$key) {
 259         return pack('H*',md5($data));
 260     }
 261     $key = str_pad($key,64,chr(0x00));
 262     if (strlen($key) > 64) {
 263         $key = pack("H*",md5($key));
 264     }
 265     $k_ipad =  $key ^ str_repeat(chr(0x36), 64) ;
 266     $k_opad =  $key ^ str_repeat(chr(0x5c), 64) ;
 267     /* Heh, let's get recursive. */
 268     $hmac=hmac_md5($k_opad . pack("H*",md5($k_ipad . $data)) );
 269     return $hmac;
 270 }
 271
 272 /**
 273  * Fillin user and password based on SMTP auth settings.
 274  *
 275  * @param string $user Reference to SMTP username
 276  * @param string $pass Reference to SMTP password (unencrypted)
 277  * @since 1.4.11
 278  */
 279 function get_smtp_user(&$user, &$pass) {
 280     global $username, $smtp_auth_mech,
 281            $smtp_sitewide_user, $smtp_sitewide_pass;
 282
 283     if ($smtp_auth_mech == 'none') {
 284         $user = '';
 285         $pass = '';
 286     } elseif ( isset($smtp_sitewide_user) && isset($smtp_sitewide_pass) &&
 287                !empty($smtp_sitewide_user)) {
 288         $user = $smtp_sitewide_user;
 289         $pass = $smtp_sitewide_pass;
 290     } else {
 291         $user = $username;
 292         $pass = sqauth_read_password();
 293     }
 294
 295     // plugin authors note: override $user or $pass by
 296     // directly changing the arguments array contents
 297     // in your plugin e.g., $args[0] = 'new_username';
 298     //
 299     $temp = array(&$user, &$pass);
 300     do_hook('smtp_auth', $temp);
 301 }