<?php
$APC_PREFIX		= 'CLIENT_';
$BAN_TTL		= 10 * 60;
$SESS_TTL		= 60 * 60;
$MAX_TRIES		= 6;
$client			= $APC_PREFIX . $_SERVER['REMOTE_ADDR'];
$tries			= apc_fetch($client);
$realmMessage	= "Resitricted Area";

require_once __DIR__ .'/ga.php';

session_start();

$_SESSION['start'] = microtime(true);
openlog("php_http_auth", 0, LOG_LOCAL0);

if (!$tries) {
	$tries = 1;
}


if (isset($_SERVER['HTTP_AUTHORIZATION'])) {
	//syslog(LOG_ERR, "Got auth");
	
	$basicStr		= str_replace('Basic ', '', $_SERVER['HTTP_AUTHORIZATION']);
	$basic			= explode(':', base64_decode($basicStr));
	$login			= array_shift($basic);
	$password		= array_shift($basic);
	$permit_auth	= false;
	$totpToken		= false;
	$sessionKey		= APC_PREFIX . $basicStr;
	$invalidKey		= $sessionKey .'_invalid';

	if (apc_fetch($sessionKey) !== false) {
		$permit_auth	= true;
	} else if ($tries <= $MAX_TRIES) {
		syslog(LOG_INFO, 'Client ' . $_SERVER['REMOTE_ADDR'] . ' has done: ' . $tries . ' tries');
		
		$uid = str_replace('_', '@', $login);
		
		$tokenPos	= strpos($uid, '|', 1);
		if ($tokenPos !== false) {
			$oldUid		= $uid;
			$totpToken	= substr($uid, ($tokenPos + 1));
			$uid		= substr($uid, 0, $tokenPos);
		}

		if (!strpos($uid, '@')) {
			//return false;
			$host = explode('.', $_SERVER['SERVER_NAME']);
			if (count($host) > 1) {
				$tld = array_pop($host);
				$dom = array_pop($host);
				$uid = $uid.'@'.$dom.'.'.$tld;
			}
		}
		
		$clientKey	= $client . $uid;
		$totpKey	= apc_fetch($clientKey);
		

		$username = substr($uid, 0, strpos($uid, '@'));
		$domain = substr($uid, strpos($uid, '@')+1);
		
		$file_db = new PDO('sqlite:/var/run/www-data/dovecot.sqlite');
		$file_db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
		
		$query = $file_db->prepare( "SELECT username || '@' || domain AS uid, password, http_totp FROM mailbox WHERE username = ? AND domain = ? LIMIT 1" );
		
		$query->execute( array( $username, $domain));
		$row = $query->fetch(PDO::FETCH_ASSOC);
		
		if($row) {
			syslog(LOG_ERR, "Found row for :" . $username .' :: '. $totpToken);
			$storedHash = $row['password'];
			if (strpos($storedHash, '}') > 0) {
				$storedHash  = substr($storedHash, strpos($storedHash, '}') +1);
			}
			
			$hashMethod = substr($storedHash, 0, 3);
			$hashSalt = substr($storedHash, ($ll = strlen($hashMethod)), strpos($storedHash, '$', $ll) - $ll);
			$inputHash = crypt($password, $hashMethod);// . $hashSalt . '$');
			if (crypt($password, $storedHash) === $storedHash) {
				syslog(LOG_ERR, "Found valid user!");
				if (!isset($_SERVER['HTTP_AUTH_PERMIT_USERS'])) {
					$permit_auth	= true;
				} else {
					$permited_users	= explode(',', preg_replace('/,\s/', '', $_SERVER['HTTP_AUTH_PERMIT_USERS']));
					if (in_array($uid, $permited_users) || in_array($username, $permited_users)) {
						$permit_auth	= true;
					}
				}
			}

			$previousToken	= apc_fetch($invalidKey);
			if ($permit_auth === true && $row['http_totp'] != null && strlen($row['http_totp']) === 16
			&& ( $previousToken === false || $previousToken !== $totpToken ) ) {
				$permit_auth	= false;
				
				$TimeStamp		= Google2FA::get_timestamp();
				$secretkey		= Google2FA::base32_decode($row['http_totp']);                 // Decode it into binary
				$otp			= Google2FA::oath_hotp($secretkey, $TimeStamp);       // Get current token
				
				if (Google2FA::verify_key($row['http_totp'], $totpToken, 1) === true) {
					syslog(LOG_INFO, 'Client ' . $_SERVER['REMOTE_ADDR'] . ' has passed two factor auth.');
					$permit_auth	= true;
					apc_store($invalidKey, $totpToken, $SESS_TTL);
				} else {
					syslog(LOG_INFO, 'Client ' . $_SERVER['REMOTE_ADDR'] . ' has FAILED two factor auth.');
				}
			}

			if ($previousToken !== false && $previousToken === $totpToken) {
				syslog(LOG_WARNING, 'POSSIBLE REPLAY ATTACK FROM HOST: '. $_SERVER['REMOTE_ADDR']);
				$tries	= $MAX_TRIES+1;
			}
		}
	}


	if ($permit_auth === true) {
		header('Content-Type: text/html; charset=utf-8', true);
		header('Content-Disposition: ""', true);
		header('Status: 200 OK', true);
		
		apc_store($sessionKey, $basicStr, $SESS_TTL);
		echo "\n\r"; // LEAVE ME HERE!
		
		exit(0);
	} else if ($permit_auth === false && $tries <= $MAX_TRIES) {
		syslog(LOG_ERR, 'HTTP Auth FAILED for ' . $uid . ' from ' . $_SERVER['REMOTE_ADDR']);
		
		apc_store($client, ++$tries, $BAN_TTL);
		
		sleep(1*$tries); // Delay them losers!
	}
}

if ($tries > $MAX_TRIES) {
	syslog(LOG_ERR, 'HTTP Auth FAILED for ' . $uid . ' from ' . $_SERVER['REMOTE_ADDR']);
	
	if ($tries == ($MAX_TRIES + 1)) {
		syslog(LOG_ERR, 'HTTP Auth BANNED for ' . $uid . ' from ' . $_SERVER['REMOTE_ADDR']);
	}
	
	apc_store($client, ++$tries, $BAN_TTL);
	sleep(1*$tries);
}

syslog(LOG_INFO, $realmMessage);
header('Content-Type: text/html; charset=utf-8', true);
header('Content-Disposition: ""', true);
header('WWW-Authenticate: Basic realm='. $realmMessage, true);
header('Status: 401 Unauthorized', true);

echo "\n\r"; // LEAVE ME HERE!

exit(0);