<?php
/*
 * ntlm_sasl_client.php
 *
 * @(#) $Id: ntlm_sasl_client.php,v 1.3 2004/11/17 08:00:37 mlemos Exp $
 *
 */

define("SASL_NTLM_STATE_START",             0);
define("SASL_NTLM_STATE_IDENTIFY_DOMAIN",   1);
define("SASL_NTLM_STATE_RESPOND_CHALLENGE", 2);
define("SASL_NTLM_STATE_DONE",              3);

class ntlm_sasl_client_class
{
	var $credentials=array();
	var $state=SASL_NTLM_STATE_START;

	Function Initialize(&$client)
	{
		if (!function_exists($function="mcrypt_encrypt") ||
		    !function_exists($function="hash"))
		{
			$extensions=array(
				"mcrypt_encrypt"=>"mcrypt",
				"hash"=>"hash"
			);
			$client->error="the extension ".$extensions[$function]." required by the NTLM SASL client class is not available in this PHP configuration";
			return(0);
		}
		return(1);
	}

	Function ASCIIToUnicode($ascii)
	{
		for ($unicode="",$a=0;$a<strlen($ascii);$a++)
			$unicode.=substr($ascii,$a,1).chr(0);
		return($unicode);
	}

	Function TypeMsg1($domain,$workstation)
	{
		$domain_length=strlen($domain);
		$workstation_length=strlen($workstation);
		$workstation_offset=32;
		$domain_offset=$workstation_offset+$workstation_length;
		return(
			"NTLMSSP\0".
			"\x01\x00\x00\x00".
			"\x07\x32\x00\x00".
			pack("v",$domain_length).
			pack("v",$domain_length).
			pack("V",$domain_offset).
			pack("v",$workstation_length).
			pack("v",$workstation_length).
			pack("V",$workstation_offset).
			$workstation.
			$domain
		);
	}

	Function NTLMResponse($challenge,$password)
	{
		$unicode=$this->ASCIIToUnicode($password);
		$md4=hash("md4", $unicode);
		$padded=$md4.str_repeat(chr(0),21-strlen($md4));
		$iv_size=mcrypt_get_iv_size(MCRYPT_DES,MCRYPT_MODE_ECB);
		$iv=mcrypt_create_iv($iv_size,MCRYPT_RAND);
		for ($response="",$third=0;$third<21;$third+=7)
		{
			for ($packed="",$p=$third;$p<$third+7;$p++)
			     $packed.=str_pad(decbin(ord(substr($padded,$p,1))),8,"0",STR_PAD_LEFT);
			for ($key="",$p=0;$p<strlen($packed);$p+=7)
			{
				$s=substr($packed,$p,7);
				$b=$s.((substr_count($s,"1") % 2) ? "0" : "1");
				$key.=chr(bindec($b));
			}
			$ciphertext=mcrypt_encrypt(MCRYPT_DES,$key,$challenge,MCRYPT_MODE_ECB,$iv);
			$response.=$ciphertext;
		}
		return $response;
	}

	Function TypeMsg3($ntlm_response,$user,$domain,$workstation)
	{
		$domain_unicode=$this->ASCIIToUnicode($domain);
		$domain_length=strlen($domain_unicode);
		$domain_offset=64;
		$user_unicode=$this->ASCIIToUnicode($user);
		$user_length=strlen($user_unicode);
		$user_offset=$domain_offset+$domain_length;
		$workstation_unicode=$this->ASCIIToUnicode($workstation);
		$workstation_length=strlen($workstation_unicode);
		$workstation_offset=$user_offset+$user_length;
		$lm="";
		$lm_length=strlen($lm);
		$lm_offset=$workstation_offset+$workstation_length;
		$ntlm=$ntlm_response;
		$ntlm_length=strlen($ntlm);
		$ntlm_offset=$lm_offset+$lm_length;
		$session="";
		$session_length=strlen($session);
		$session_offset=$ntlm_offset+$ntlm_length;
		return(
			"NTLMSSP\0".
			"\x03\x00\x00\x00".
			pack("v",$lm_length).
			pack("v",$lm_length).
			pack("V",$lm_offset).
			pack("v",$ntlm_length).
			pack("v",$ntlm_length).
			pack("V",$ntlm_offset).
			pack("v",$domain_length).
			pack("v",$domain_length).
			pack("V",$domain_offset).
			pack("v",$user_length).
			pack("v",$user_length).
			pack("V",$user_offset).
			pack("v",$workstation_length).
			pack("v",$workstation_length).
			pack("V",$workstation_offset).
			pack("v",$session_length).
			pack("v",$session_length).
			pack("V",$session_offset).
			"\x01\x02\x00\x00".
			$domain_unicode.
			$user_unicode.
			$workstation_unicode.
			$lm.
			$ntlm
		);
	}

	Function Start(&$client, &$message, &$interactions)
	{
		if ($this->state!=SASL_NTLM_STATE_START)
		{
			$client->error="NTLM authentication state is not at the start";
			return(SASL_FAIL);
		}
		$this->credentials=array(
			"user"=>"",
			"password"=>"",
			"realm"=>"",
			"workstation"=>""
		);
		$defaults=array();
		$status=$client->GetCredentials($this->credentials,$defaults,$interactions);
		if ($status==SASL_CONTINUE)
			$this->state=SASL_NTLM_STATE_IDENTIFY_DOMAIN;
		Unset($message);
		return($status);
	}

	Function Step(&$client, $response, &$message, &$interactions)
	{
		switch ($this->state)
		{
			case SASL_NTLM_STATE_IDENTIFY_DOMAIN:
				$message=$this->TypeMsg1($this->credentials["realm"],$this->credentials["workstation"]);
				$this->state=SASL_NTLM_STATE_RESPOND_CHALLENGE;
				break;
			case SASL_NTLM_STATE_RESPOND_CHALLENGE:
				$ntlm_response=$this->NTLMResponse(substr($response,24,8),$this->credentials["password"]);
				$message=$this->TypeMsg3($ntlm_response,$this->credentials["user"],$this->credentials["realm"],$this->credentials["workstation"]);
				$this->state=SASL_NTLM_STATE_DONE;
				break;
			case SASL_NTLM_STATE_DONE:
				$client->error="NTLM authentication was finished without success";
				return(SASL_FAIL);
			default:
				$client->error="invalid NTLM authentication step state";
				return(SASL_FAIL);
		}
		return(SASL_CONTINUE);
	}
};

?>