functions/auth.php

   1 <?php
   2
   3 /**
   4  * auth.php
   5  *
   6  * Copyright (c) 1999-2004 The SquirrelMail Project Team
   7  * Licensed under the GNU GPL. For full terms see the file COPYING.
   8  *
   9  * Contains functions used to do authentication.
  10  *
  11  * @version $Id$
  12  * @package squirrelmail
  13  */
  14
  15 /** Put in a safety net here, in case a naughty admin didn't run conf.pl when they upgraded */
  16
  17 if (! isset($smtp_auth_mech)) {
  18   $smtp_auth_mech = 'none';
  19 }
  20
  21 if (! isset($imap_auth_mech)) {
  22   $imap_auth_mech = 'login';
  23 }
  24
  25 if (! isset($use_imap_tls)) {
  26   $use_imap_tls = false;
  27 }
  28
  29 if (! isset($use_smtp_tls)) {
  30   $use_smtp_tls = false;
  31 }
  32
  33 /**
  34  * Check if user has previously logged in to the Squirrelmail session.  If user
  35  * has not logged in, execution will stop inside this function.
  36  *
  37  * @return int A positive value is returned if user has previously logged in
  38  * successfully.
  39  */
  40 function is_logged_in() {
  41
  42     if ( sqsession_is_registered('user_is_logged_in') ) {
  43         return;
  44     } else {
  45         global $PHP_SELF, $session_expired_post,
  46                $session_expired_location, $squirrelmail_language;
  47
  48         /*  First we store some information in the new session to prevent
  49          *  information-loss.
  50          */
  51
  52         $session_expired_post = $_POST;
  53         $session_expired_location = $PHP_SELF;
  54         if (!sqsession_is_registered('session_expired_post')) {
  55            sqsession_register($session_expired_post,'session_expired_post');
  56         }
  57         if (!sqsession_is_registered('session_expired_location')) {
  58            sqsession_register($session_expired_location,'session_expired_location');
  59         }
  60         include_once( SM_PATH . 'functions/display_messages.php' );
  61         set_up_language($squirrelmail_language, true);
  62         logout_error( _("You must be logged in to access this page.") );
  63         exit;
  64     }
  65 }
  66
  67 /**
  68  * Given the challenge from the server, supply the response using cram-md5 (See
  69  * RFC 2195 for details)
  70  *
  71  * @param string $username User ID
  72  * @param string $password User password supplied by User
  73  * @param string $challenge The challenge supplied by the server
  74  * @return string The response to be sent to the IMAP server
  75  *
  76  */
  77 function cram_md5_response ($username,$password,$challenge) {
  78     $challenge=base64_decode($challenge);
  79     $hash=bin2hex(hmac_md5($challenge,$password));
  80     $response=base64_encode($username . " " . $hash) . "\r\n";
  81     return $response;
  82 }
  83
  84 /**
  85  * Return Digest-MD5 response.
  86  * Given the challenge from the server, calculate and return the
  87  * response-string for digest-md5 authentication.  (See RFC 2831 for more
  88  * details)
  89  *
  90  * @param string $username User ID
  91  * @param string $password User password supplied by User
  92  * @param string $challenge The challenge supplied by the server
  93  * @param string $service The service name, usually 'imap'; it is used to
  94  *   define the digest-uri.
  95  * @param string $host The host name, usually the server's FQDN; it is used to
  96  *   define the digest-uri.
  97  * @return string The response to be sent to the IMAP server
  98  */
  99 function digest_md5_response ($username,$password,$challenge,$service,$host) {
 100   $result=digest_md5_parse_challenge($challenge);
 101
 102 // verify server supports qop=auth
 103   // $qop = explode(",",$result['qop']);
 104   //if (!in_array("auth",$qop)) {
 105     // rfc2831: client MUST fail if no qop methods supported
 106    // return false;
 107   //}
 108   $cnonce = base64_encode(bin2hex(hmac_md5(microtime())));
 109   $ncount = "00000001";
 110
 111   /* This can be auth (authentication only), auth-int (integrity protection), or
 112      auth-conf (confidentiality protection).  Right now only auth is supported.
 113          DO NOT CHANGE THIS VALUE */
 114   $qop_value = "auth";
 115
 116   $digest_uri_value = $service . '/' . $host;
 117
 118   // build the $response_value
 119   //FIXME This will probably break badly if a server sends more than one realm
 120   $string_a1 = utf8_encode($username).":";
 121   $string_a1 .= utf8_encode($result['realm']).":";
 122   $string_a1 .= utf8_encode($password);
 123   $string_a1 = hmac_md5($string_a1);
 124   $A1 = $string_a1 . ":" . $result['nonce'] . ":" . $cnonce;
 125   $A1 = bin2hex(hmac_md5($A1));
 126   $A2 = "AUTHENTICATE:$digest_uri_value";
 127   // If qop is auth-int or auth-conf, A2 gets a little extra
 128   if ($qop_value != 'auth') {
 129     $A2 .= ':00000000000000000000000000000000';
 130   }
 131   $A2 = bin2hex(hmac_md5($A2));
 132
 133   $string_response = $result['nonce'] . ':' . $ncount . ':' . $cnonce . ':' . $qop_value;
 134   $response_value = bin2hex(hmac_md5($A1.":".$string_response.":".$A2));
 135
 136   $reply = 'charset=utf-8,username="' . $username . '",realm="' . $result["realm"] . '",';
 137   $reply .= 'nonce="' . $result['nonce'] . '",nc=' . $ncount . ',cnonce="' . $cnonce . '",';
 138   $reply .= "digest-uri=\"$digest_uri_value\",response=$response_value";
 139   $reply .= ',qop=' . $qop_value;
 140   $reply = base64_encode($reply);
 141   return $reply . "\r\n";
 142
 143 }
 144
 145 /**
 146  * Parse Digest-MD5 challenge.
 147  * This function parses the challenge sent during DIGEST-MD5 authentication and
 148  * returns an array. See the RFC for details on what's in the challenge string.
 149  *
 150  * @param string $challenge Digest-MD5 Challenge
 151  * @return array Digest-MD5 challenge decoded data
 152  */
 153 function digest_md5_parse_challenge($challenge) {
 154   $challenge=base64_decode($challenge);
 155   while (isset($challenge)) {
 156     if ($challenge{0} == ',') { // First char is a comma, must not be 1st time through loop
 157       $challenge=substr($challenge,1);
 158     }
 159     $key=explode('=',$challenge,2);
 160     $challenge=$key[1];
 161     $key=$key[0];
 162     if ($challenge{0} == '"') {
 163       // We're in a quoted value
 164       // Drop the first quote, since we don't care about it
 165       $challenge=substr($challenge,1);
 166       // Now explode() to the next quote, which is the end of our value
 167       $val=explode('"',$challenge,2);
 168       $challenge=$val[1]; // The rest of the challenge, work on it in next iteration of loop
 169       $value=explode(',',$val[0]);
 170       // Now, for those quoted values that are only 1 piece..
 171       if (sizeof($value) == 1) {
 172         $value=$value[0];  // Convert to non-array
 173       }
 174     } else {
 175       // We're in a "simple" value - explode to next comma
 176       $val=explode(',',$challenge,2);
 177       if (isset($val[1])) {
 178                 $challenge=$val[1];
 179           } else {
 180             unset($challenge);
 181           }
 182       $value=$val[0];
 183     }
 184     $parsed["$key"]=$value;
 185   } // End of while loop
 186   return $parsed;
 187 }
 188
 189 /**
 190  * Creates a HMAC digest that can be used for auth purposes
 191  * See RFCs 2104, 2617, 2831
 192  * Uses mhash() extension if available
 193  *
 194  * @param string $data Data to apply hash function to.
 195  * @param string $key Optional key, which, if supplied, will be used to
 196  * calculate data's HMAC.
 197  * @return string HMAC Digest string
 198  */
 199 function hmac_md5($data, $key='') {
 200     if (extension_loaded('mhash')) {
 201       if ($key== '') {
 202         $mhash=mhash(MHASH_MD5,$data);
 203       } else {
 204         $mhash=mhash(MHASH_MD5,$data,$key);
 205       }
 206       return $mhash;
 207     }
 208     if (!$key) {
 209          return pack('H*',md5($data));
 210     }
 211     $key = str_pad($key,64,chr(0x00));
 212     if (strlen($key) > 64) {
 213         $key = pack("H*",md5($key));
 214     }
 215     $k_ipad =  $key ^ str_repeat(chr(0x36), 64) ;
 216     $k_opad =  $key ^ str_repeat(chr(0x5c), 64) ;
 217     /* Heh, let's get recursive. */
 218     $hmac=hmac_md5($k_opad . pack("H*",md5($k_ipad . $data)) );
 219     return $hmac;
 220 }
 221
 222 /**
 223  * Fillin user and password based on SMTP auth settings.
 224  *
 225  * @param string $user Reference to SMTP username
 226  * @param string $pass Reference to SMTP password (unencrypted)
 227  */
 228 function get_smtp_user(&$user, &$pass) {
 229     global $username, $smtp_auth_mech,
 230            $smtp_sitewide_user, $smtp_sitewide_pass;
 231
 232     if ($smtp_auth_mech == 'none') {
 233         $user = '';
 234         $pass = '';
 235     } elseif ( isset($smtp_sitewide_user) && isset($smtp_sitewide_pass) ) {
 236         $user = $smtp_sitewide_user;
 237         $pass = $smtp_sitewide_pass;
 238     } else {
 239         global $key, $onetimepad;
 240         $user = $username;
 241         $pass = OneTimePadDecrypt($key, $onetimepad);
 242     }
 243 }
 244
 245 ?>