Veiligheid loginsysteem

<?php 
//login.php

//cleanQuery
function cleanQuery($string)
{
  if(get_magic_quotes_gpc())  
  {
    $string = stripslashes($string);
  }
  if (phpversion() >= '4.3.0')
  {
    $string = mysql_real_escape_string($string);
  }
  else
  {
    $string = mysql_escape_string($string);
  }
  return $string;
}

//salt
function salt($pass, $salt, $str="")
{
    $pass = str_replace(" ", "", $pass);
    $pass = strrev($pass);

    $arr[0] = strlen($pass);
    $arr[1] = strlen($salt);
    
    while($arr[0] > $arr[1] + 1)
    {
        $salt = $salt.$salt;
        $arr[1] = strlen($salt);
    }

    $split_len = floor(max($arr) / (min($arr) - 1));
    
    $salt = explode(" ", chunk_split($salt, $split_len, " "));
    array_pop($salt);
    $salt = array_reverse($salt);
    
    $j = $arr[0] > count($salt) ? $arr[0] : count($salt);
    
    for($i=0; $i<$j; $i++)
    {
        if(isset($pass{$i}))    $str .= $pass{$i};
        if(isset($salt[$i]))    $str .= $salt[$i];
    }
    
    return $str;
}
 
$logingoto = "admin.php";
$validate = "validate.php";
$error = "form.php";

if (isset($_SESSION['visit'])) 
{
	$_SESSION['user'] = NULL;
	unset($_SESSION['user']);
	$_SESSION['ip'] = NULL;
	unset($_SESSION['ip']);
	$_SESSION['id'] = NULL;
	unset($_SESSION['id']);
	$_SESSION['logged'] = NULL;
	unset($_SESSION['logged']);
	
	session_destroy();
}

if (!isset($_SESSION)) 
	{  session_start(); }

require('connections/connection.php'); 

if (isset($_POST['login']))
{ 
  
  $username = cleanQuery($_POST['username']);
  $password = hash('sha256', salt($_POST['password'], 'randomnummersencijfers'));
  $ip = cleanQuery($_POST['ip']);
  $ip_check = cleanQuery($_SERVER['REMOTE_ADDR']);

  $query = mysql_query ("SELECT * FROM `users` WHERE username = '$username' ");
  $numrows = mysql_num_rows($query);
  $row = mysql_fetch_assoc($query);
  
  if($row['attempt'] % 3 == 0)  
  {
	  if (strtotime("now") < $row['attempt'])
	  {
		  echo "to soon";
		  die ;
	  }
	  else
	  {
		$outtime = strtotime("now + 2 hours");
		mysql_query("UPDATE `users` SET `outtime` = '$outtime' WHERE `id` = " . $row['id']);
		header ("Location: " . root() );
		die;
	  }
  }	 
  
  else
  { 
  	if ($row['emailcheck'] == 1 )
	{
	  if ($username && $password)
	  {	  
		  if ($numrows != 0 and $row['type'] != 0)
		  {
			  $dbusername = $row['username'];
			  $dbpassword = $row['password'];
			  $id = $row['id'];
			  
			  if ($username == $dbusername && $password == $dbpassword)
			  {
				  $session_id = rand(100000000,999999999);
	
				  $_SESSION['login'] = TRUE ;
				  $_SESSION['user'] = $row['id'];
				  $_SESSION['id'] = $session_id;
				  
				  $insert_session_id = mysql_query("UPDATE `users` SET `session` = '" . $session_id . "' , `attempt` = 1 WHERE `id` = " . $row['id'] );
				  
				  if (isset($_POST['verify']))
				  {
					  $verify = hash('sha256', salt(cleanQuery($_POST['verify']), 'randomnummersencijfers'));			
										  
					  $check_query = mysql_query("SELECT * FROM `users` WHERE `id` = " . $id . " AND `verify` = '$verify' ");
					  $numrows_q = mysql_num_rows($check_query);
					  
					  if (isset($numrows_q) and @$numrows_q != 0 and $ip == $ip_check)
					  {
						  $insert_ip = mysql_query("INSERT INTO `userip` (`uid`, `ip`) VALUES (".$id.",'$ip')");					
					  }
					  
					  else
					  {
						  header("Location: $error");
						  die;
					  }
				  }
				  
				  if ($ip == $ip_check)
				  {
					  $ip_query = mysql_query("SELECT * FROM `userip` WHERE `uid` = " . $row['id'] . " AND `ip` = '$ip' ");
					  @$ip_row = mysql_fetch_assoc($ip_query);
					  @$numrowsip = mysql_num_rows($ip_query);
				  
					  if (isset($numrowsip) and @$numrowsip != 0 and $ip_row['logged'] != 1)
					  {
						  //mysql_query("UPDATE `userip` SET `logged` = " . 1 . " WHERE `ip` = '$ip' AND `uid` = " . $id );
						  mysql_query("UPDATE `users` SET `logged` = '$ip', `attempt` = 1 WHERE `id` = " . $id );
						  $_SESSION['ip'] = $ip ;
						  header("Location: $logingoto");
						  die ;
					  }
					  
					  elseif ($ip_row['logged'] == 1)
					  {
						  header ("Location: $error");
						  die ;
					  }
					  
					  else 
					  {
						  include('admin/layout/head.php');
						  include('admin/validate.php');
						  die ;
					  }
				  }				
			  }
	  
			  else 
				{ 
					$max = maximum('attempt', 'users', 'id', $id);
					@mysql_query("UPDATE `users` SET `attempt` = " . $max . " WHERE `id` = " . $id );
					header("Location: $error"); die ; 
				}	
		  }
	  
		  else 
		  { 
			$max = maximum('attempt', 'users', 'id', $id) ;
			@mysql_query("UPDATE `users` SET `attempt` = " . $max . " WHERE `id` = " . $id );
			header("Location: $error"); die ;
		  }
	  }
	  
	  else
	  {
		  $max = maximum('attempt', 'users', 'id', $id); 
		  @mysql_query("UPDATE `users` SET `attempt` = " . $max . " WHERE `id` = " . $id );
		  header("Location: $error"); die ; 
	  }	
	}
	
	elseif (isset($_POST['email']))
	{ 
		$email_ver = mysql_query("UPDATE `users` SET `emailcheck` = 1 WHERE `id` = " . $row['id'] ); 
		if (isset($email_ver)) { header("location: " . root()."verify"); die; }
		else echo mysql_error();
	}
	else	
	{ 
		header("Location: $error"); die ; 
	}
  }  
}

?>
het formulier:
        <form action="login.php" method="POST">
            <p>Naam:<br /><input type="text" name="username" class="login"></p>
            <p>Wachtwoord:<br /> <input type="password" name="password" class="login" ></p>
            <input type="submit" name="login" class="logbutton" value="Login">
            <input type="hidden" name="ip" value="<?php echo $_SERVER['REMOTE_ADDR'];?>" />
        </form>