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