functions/auth.php

   1 <?php
   2
   3 /**
   4  * auth.php
   5  *
   6  * Contains functions used to do authentication. Library depends on
   7  * functions from functions/global.php, functions/i18n.php and
   8  * functions/strings.php.
   9  *
  10  * @copyright &copy; 1999-2006 The SquirrelMail Project Team
  11  * @license http://opensource.org/licenses/gpl-license.php GNU Public License
  12  * @version $Id$
  13  * @package squirrelmail
  14  */
  15
  16
  17 /**
  18  * Detect logged user
  19  *
  20  * Function is similar to is_logged_in() function. If user is logged in, function
  21  * returns true. If user is not logged in or session is expired, function saves $_POST
  22  * and $PHP_SELF in session and returns false. POST information is saved in
  23  * 'session_expired_post' variable, PHP_SELF is saved in 'session_expired_location'.
  24  *
  25  * Script that uses this function instead of is_logged_in() function, must handle user
  26  * level messages.
  27  * @return boolean
  28  * @since 1.5.1
  29  */
  30 function sqauth_is_logged_in() {
  31     if ( sqsession_is_registered('user_is_logged_in') ) {
  32         return true;
  33     } else {
  34         global $PHP_SELF, $session_expired_post, $session_expired_location;
  35
  36         //  First we store some information in the new session to prevent
  37         //  information-loss.
  38         //
  39         $session_expired_post = $_POST;
  40         $session_expired_location = $PHP_SELF;
  41         if (!sqsession_is_registered('session_expired_post')) {
  42             sqsession_register($session_expired_post,'session_expired_post');
  43         }
  44         if (!sqsession_is_registered('session_expired_location')) {
  45             sqsession_register($session_expired_location,'session_expired_location');
  46         }
  47
  48         return false;
  49      }
  50 }
  51
  52 /**
  53  * Reads and decodes stored user password information
  54  *
  55  * Direct access to password information is deprecated.
  56  * @return string password in plain text
  57  * @since 1.5.1
  58  */
  59 function sqauth_read_password() {
  60     sqgetGlobalVar('key',         $key,       SQ_COOKIE);
  61     sqgetGlobalVar('onetimepad',  $onetimepad,SQ_SESSION);
  62
  63     return OneTimePadDecrypt($key, $onetimepad);
  64 }
  65
  66 /**
  67  * Saves or updates user password information
  68  *
  69  * This function is used to update password information that SquirrelMail
  70  * stores during existing web session. It does not modify password stored
  71  * in authentication system used by IMAP server.
  72  *
  73  * Function must be called before any html output started. Direct access
  74  * to password information is deprecated. Saved password information is
  75  * available only to next executed SquirrelMail script. If your script needs
  76  * access to saved password after sqauth_save_password() call, use returned
  77  * OTP encrypted key.
  78  * @param string $pass password
  79  * @return string password encrypted with OTP. In case script wants to access
  80  *  password information before reloading page.
  81  * @since 1.5.1
  82  */
  83 function sqauth_save_password($pass) {
  84     sqgetGlobalVar('base_uri',    $base_uri,   SQ_SESSION);
  85
  86     $onetimepad = OneTimePadCreate(strlen($pass));
  87     sqsession_register($onetimepad,'onetimepad');
  88     $key = OneTimePadEncrypt($pass, $onetimepad);
  89     sqsetcookie('key', $key, false, $base_uri);
  90     return $key;
  91 }
  92
  93 /**
  94  * Given the challenge from the server, supply the response using cram-md5 (See
  95  * RFC 2195 for details)
  96  *
  97  * @param string $username User ID
  98  * @param string $password User password supplied by User
  99  * @param string $challenge The challenge supplied by the server
 100  * @return string The response to be sent to the IMAP server
 101  * @since 1.4.0
 102  */
 103 function cram_md5_response ($username,$password,$challenge) {
 104     $challenge=base64_decode($challenge);
 105     $hash=bin2hex(hmac_md5($challenge,$password));
 106     $response=base64_encode($username . " " . $hash) . "\r\n";
 107     return $response;
 108 }
 109
 110 /**
 111  * Return Digest-MD5 response.
 112  * Given the challenge from the server, calculate and return the
 113  * response-string for digest-md5 authentication.  (See RFC 2831 for more
 114  * details)
 115  *
 116  * @param string $username User ID
 117  * @param string $password User password supplied by User
 118  * @param string $challenge The challenge supplied by the server
 119  * @param string $service The service name, usually 'imap'; it is used to
 120  *   define the digest-uri.
 121  * @param string $host The host name, usually the server's FQDN; it is used to
 122  *   define the digest-uri.
 123  * @return string The response to be sent to the IMAP server
 124  * @since 1.4.0
 125  */
 126 function digest_md5_response ($username,$password,$challenge,$service,$host) {
 127     $result=digest_md5_parse_challenge($challenge);
 128
 129     // verify server supports qop=auth
 130     // $qop = explode(",",$result['qop']);
 131     //if (!in_array("auth",$qop)) {
 132     // rfc2831: client MUST fail if no qop methods supported
 133     // return false;
 134     //}
 135     $cnonce = base64_encode(bin2hex(hmac_md5(microtime())));
 136     $ncount = "00000001";
 137
 138     /* This can be auth (authentication only), auth-int (integrity protection), or
 139        auth-conf (confidentiality protection).  Right now only auth is supported.
 140        DO NOT CHANGE THIS VALUE */
 141     $qop_value = "auth";
 142
 143     $digest_uri_value = $service . '/' . $host;
 144
 145     // build the $response_value
 146     //FIXME This will probably break badly if a server sends more than one realm
 147     $string_a1 = utf8_encode($username).":";
 148     $string_a1 .= utf8_encode($result['realm']).":";
 149     $string_a1 .= utf8_encode($password);
 150     $string_a1 = hmac_md5($string_a1);
 151     $A1 = $string_a1 . ":" . $result['nonce'] . ":" . $cnonce;
 152     $A1 = bin2hex(hmac_md5($A1));
 153     $A2 = "AUTHENTICATE:$digest_uri_value";
 154     // If qop is auth-int or auth-conf, A2 gets a little extra
 155     if ($qop_value != 'auth') {
 156         $A2 .= ':00000000000000000000000000000000';
 157     }
 158     $A2 = bin2hex(hmac_md5($A2));
 159
 160     $string_response = $result['nonce'] . ':' . $ncount . ':' . $cnonce . ':' . $qop_value;
 161     $response_value = bin2hex(hmac_md5($A1.":".$string_response.":".$A2));
 162
 163     $reply = 'charset=utf-8,username="' . $username . '",realm="' . $result["realm"] . '",';
 164     $reply .= 'nonce="' . $result['nonce'] . '",nc=' . $ncount . ',cnonce="' . $cnonce . '",';
 165     $reply .= "digest-uri=\"$digest_uri_value\",response=$response_value";
 166     $reply .= ',qop=' . $qop_value;
 167     $reply = base64_encode($reply);
 168     return $reply . "\r\n";
 169
 170 }
 171
 172 /**
 173  * Parse Digest-MD5 challenge.
 174  * This function parses the challenge sent during DIGEST-MD5 authentication and
 175  * returns an array. See the RFC for details on what's in the challenge string.
 176  *
 177  * @param string $challenge Digest-MD5 Challenge
 178  * @return array Digest-MD5 challenge decoded data
 179  * @since 1.4.0
 180  */
 181 function digest_md5_parse_challenge($challenge) {
 182     $challenge=base64_decode($challenge);
 183     while (isset($challenge)) {
 184         if ($challenge{0} == ',') { // First char is a comma, must not be 1st time through loop
 185             $challenge=substr($challenge,1);
 186         }
 187         $key=explode('=',$challenge,2);
 188         $challenge=$key[1];
 189         $key=$key[0];
 190         if ($challenge{0} == '"') {
 191             // We're in a quoted value
 192             // Drop the first quote, since we don't care about it
 193             $challenge=substr($challenge,1);
 194             // Now explode() to the next quote, which is the end of our value
 195             $val=explode('"',$challenge,2);
 196             $challenge=$val[1]; // The rest of the challenge, work on it in next iteration of loop
 197             $value=explode(',',$val[0]);
 198             // Now, for those quoted values that are only 1 piece..
 199             if (sizeof($value) == 1) {
 200                 $value=$value[0];  // Convert to non-array
 201             }
 202         } else {
 203             // We're in a "simple" value - explode to next comma
 204             $val=explode(',',$challenge,2);
 205             if (isset($val[1])) {
 206                 $challenge=$val[1];
 207             } else {
 208                 unset($challenge);
 209             }
 210             $value=$val[0];
 211         }
 212         $parsed["$key"]=$value;
 213     } // End of while loop
 214     return $parsed;
 215 }
 216
 217 /**
 218  * Creates a HMAC digest that can be used for auth purposes
 219  * See RFCs 2104, 2617, 2831
 220  * Uses mhash() extension if available
 221  *
 222  * @param string $data Data to apply hash function to.
 223  * @param string $key Optional key, which, if supplied, will be used to
 224  * calculate data's HMAC.
 225  * @return string HMAC Digest string
 226  * @since 1.4.0
 227  */
 228 function hmac_md5($data, $key='') {
 229     if (extension_loaded('mhash')) {
 230         if ($key== '') {
 231             $mhash=mhash(MHASH_MD5,$data);
 232         } else {
 233             $mhash=mhash(MHASH_MD5,$data,$key);
 234         }
 235         return $mhash;
 236     }
 237     if (!$key) {
 238         return pack('H*',md5($data));
 239     }
 240     $key = str_pad($key,64,chr(0x00));
 241     if (strlen($key) > 64) {
 242         $key = pack("H*",md5($key));
 243     }
 244     $k_ipad =  $key ^ str_repeat(chr(0x36), 64) ;
 245     $k_opad =  $key ^ str_repeat(chr(0x5c), 64) ;
 246     /* Heh, let's get recursive. */
 247     $hmac=hmac_md5($k_opad . pack("H*",md5($k_ipad . $data)) );
 248     return $hmac;
 249 }
 250
 251 /**
 252  * Fillin user and password based on SMTP auth settings.
 253  *
 254  * @param string $user Reference to SMTP username
 255  * @param string $pass Reference to SMTP password (unencrypted)
 256  * @since 1.5.0
 257  */
 258 function get_smtp_user(&$user, &$pass) {
 259     global $username, $smtp_auth_mech,
 260            $smtp_sitewide_user, $smtp_sitewide_pass;
 261
 262     if ($smtp_auth_mech == 'none') {
 263         $user = '';
 264         $pass = '';
 265     } elseif ( isset($smtp_sitewide_user) && isset($smtp_sitewide_pass) ) {
 266         $user = $smtp_sitewide_user;
 267         $pass = $smtp_sitewide_pass;
 268     } else {
 269         $user = $username;
 270         $pass = sqauth_read_password();
 271     }
 272 }
 273
 274 ?>