1: <?php
  2: /**
  3:  * IMSP authentication class for CRAM-MD5 authentication.
  4:  *
  5:  * Required parameters:<pre>
  6:  *   'username'  Username to logon to IMSP server as.
  7:  *   'password'  Password for current user.
  8:  *   'server'    The hostname of the IMSP server.
  9:  *   'port'      The port of the IMSP server.</pre>
 10:  *
 11:  * Copyright 2003-2012 Horde LLC (http://www.horde.org/)
 12:  *
 13:  * See the enclosed file COPYING for license information (LGPL). If you
 14:  * did not receive this file, see http://www.horde.org/licenses/lgpl21.
 15:  *
 16:  * @author  Michael Rubinsky <mrubinsk@horde.org>
 17:  * @package Horde_Imsp
 18:  */
 19: class Horde_Imsp_Auth_CramMd5 extends Horde_Imsp_Auth_Base
 20: {
 21:     /**
 22:      * Private authentication function.  Provides actual authentication code.
 23:      *
 24:      * @return boolean
 25:      */
 26:     protected function _authenticate()
 27:     {
 28:         $userId = $this->_params['username'];
 29:         $credentials = $this->_params['password'];
 30:         $this->_imsp->send('AUTHENTICATE CRAM-MD5');
 31: 
 32:         /* Get response and decode it. */
 33:         $server_response = $this->_imsp->receive();
 34:         $server_response = base64_decode(trim(substr($server_response, 2)));
 35: 
 36:         /* Build and base64 encode the response to the challange. */
 37:         $response_to_send = $userId . ' ' . $this->_hmac($credentials, $server_response);
 38:         $command_string = base64_encode($response_to_send);
 39: 
 40:         /* Send the response. */
 41:         $this->_imsp->send($command_string, false);
 42:         $result = $this->_imsp->receive();
 43: 
 44:         if ($result != 'OK') {
 45:             $this->_imsp->_logger->err('Login to IMSP host failed.');
 46:             return false;
 47:         }
 48: 
 49:         return true;
 50:     }
 51: 
 52:     /**
 53:      * RFC 2104 HMAC implementation.
 54:      *
 55:      * @access private
 56:      * @param  string  $key    The HMAC key.
 57:      * @param  string  $data   The data to hash with the key.
 58:      *
 59:      * @return string  The MD5 HMAC.
 60:      */
 61:     protected function _hmac($key, $data)
 62:     {
 63:         if (function_exists('hash_hmac')) {
 64:             return hash_hmac('md5', $data, $key);
 65:         }
 66: 
 67:         /* Byte length for md5. */
 68:         $b = 64;
 69: 
 70:         if (strlen($key) > $b) {
 71:             $key = pack('H*', md5($key));
 72:         }
 73: 
 74:         $key = str_pad($key, $b, chr(0x00));
 75:         $ipad = str_pad('', $b, chr(0x36));
 76:         $opad = str_pad('', $b, chr(0x5c));
 77:         $k_ipad = $key ^ $ipad;
 78:         $k_opad = $key ^ $opad;
 79:         return md5($k_opad . pack('H*', md5($k_ipad . $data)));
 80:     }
 81: 
 82:     /**
 83:      * Force a logout command to the imsp stream.
 84:      *
 85:      */
 86:     public function logout()
 87:     {
 88:         $this->_imsp->logout();
 89:     }
 90: 
 91:     /**
 92:      * Return the driver type
 93:      *
 94:      * @return string the type of this IMSP_Auth driver
 95:      */
 96:      public function getDriverType()
 97:      {
 98:          return 'cram_md5';
 99:      }
100: 
101: }
102: