Beveiligingsvraag

// Veiligheids check
$paginatest = "(http:|ftp:|shttp: |https: |www.|.php|.cgi|.asp)"; 
if(eregi($paginatest, $pagina))	{ $pagina = "main"; }

// Veiligheidscheck 2
$pagina_inc = $pagina . ".php";
if (!file_exists($pagina_inc)) { $pagina = "main"; }

// Veiligheids check
$paginatest = "(http:|ftp:|shttp: |https: |www.|.php|.cgi|.asp)"; 
if(eregi($paginatest, $pagina))	{ $pagina = "main"; }
 
// Veiligheidscheck 2
$pagina_inc = $pagina . ".php";
if (!file_exists($pagina_inc)) { $pagina = "main"; }

function filter($text){
									
//transformeert eerst de "goede" tags naar hun bb versie, zodat ze door het strip_tags filter niet aangetast worden.
	$text = preg_replace("(<img src=\"(.+?)\" border=\"0\">)", "\[img\]$1\[/img\]", $text);
	$text = preg_replace("(<b>(.+?)</b>)", "\[b\]$1\[/b\]", $text);
	$text = preg_replace("(<u>(.+?)</u>)", "\[u\]$1\[/u\]", $text);
	$text = preg_replace("(<i>(.+?)</i>)", "\[i\]$1\[/i\]", $text);
	$text = preg_replace("(<strike>(.+?)</strike>)", "\[s\]$1\[/s\]", $text);
	$text = preg_replace("(<div align=\"left\">(.+?)</div>)", "\[left\]$1\[/left\]", $text);
	$text = preg_replace("(<div align=\"right\">(.+?)</div>)", "\[right\]$1\[/right\]", $text);
	$text = preg_replace("(<center>(.+?)</center>)", "\[center\]$1\[/center\]", $text);
	$text = eregi_replace("<font color=\"([^\\[]*)\">([^\\[]*)</font>","\\[color=\\1\\]\\2\\[/color\\]",$text);
	$text = eregi_replace("<font size=\"([^\\[]*)\">([^\\[]*)</font>","\\[size=\\1\\]\\2\\[/size\\]",$text);
	$text = eregi_replace("<a href=\"mailto:([^\\[]*)\">([^\\[]*)</a>","\\[email=\\1\\]\\2\\[/email\\]",$text); 
	$text = eregi_replace("<a href=\"([^\\[]*)\" target=\"_blank\">([^\\[]*)</a>","\\[url=\\1\\]\\2\\[/url\\]",$text); 
	$text = preg_replace("(<marquee>(.+?)</marquee>)","\[move\]$1\[/move\]", $text);
								
	$text = strip_tags($text);
	$text = htmlentities($text, ENT_QUOTES);
	
	$text = addslashes($text);
	return $text;
}

function filter($text){
 
//transformeert eerst de "goede" tags naar hun bb versie, zodat ze door het strip_tags filter niet aangetast worden.
	$text = preg_replace("(<img src=\"(.+?)\" border=\"0\">)", "\[img\]$1\[/img\]", $text);
	$text = preg_replace("(<b>(.+?)</b>)", "\[b\]$1\[/b\]", $text);
	$text = preg_replace("(<u>(.+?)</u>)", "\[u\]$1\[/u\]", $text);
	$text = preg_replace("(<i>(.+?)</i>)", "\[i\]$1\[/i\]", $text);
	$text = preg_replace("(<strike>(.+?)</strike>)", "\[s\]$1\[/s\]", $text);
	$text = preg_replace("(<div align=\"left\">(.+?)</div>)", "\[left\]$1\[/left\]", $text);
	$text = preg_replace("(<div align=\"right\">(.+?)</div>)", "\[right\]$1\[/right\]", $text);
	$text = preg_replace("(<center>(.+?)</center>)", "\[center\]$1\[/center\]", $text);
	$text = eregi_replace("<font color=\"([^\\[]*)\">([^\\[]*)</font>","\\[color=\\1\\]\\2\\[/color\\]",$text);
	$text = eregi_replace("<font size=\"([^\\[]*)\">([^\\[]*)</font>","\\[size=\\1\\]\\2\\[/size\\]",$text);
	$text = eregi_replace("<a href=\"mailto:([^\\[]*)\">([^\\[]*)</a>","\\[email=\\1\\]\\2\\[/email\\]",$text); 
	$text = eregi_replace("<a href=\"([^\\[]*)\" target=\"_blank\">([^\\[]*)</a>","\\[url=\\1\\]\\2\\[/url\\]",$text); 
	$text = preg_replace("(<marquee>(.+?)</marquee>)","\[move\]$1\[/move\]", $text);
 
	$text = strip_tags($text);
	$text = htmlentities($text, ENT_QUOTES);
 
	$text = addslashes($text);
	return $text;
}

	// Metatags van $_POST en $_GET filteren i.v.m. cross site scripting
	if(sizeof($_GET) > 1) {
		foreach($_GET as $post => $waarde) {
			$_GET[$post] = trim(strip_tags($waarde));
		}
    }
	if(sizeof($_POST) > 1) {
		foreach($_POST as $post => $waarde) {
			$_POST[$post] = trim(strip_tags($waarde));
		}
    }
	if(sizeof($_SESSION) > 1) {
		foreach($_SESSION as $post => $waarde) {
			$_SESSION[$post] = trim(strip_tags($waarde));
		}
    }

// Metatags van $_POST en $_GET filteren i.v.m. cross site scripting
	if(sizeof($_GET) > 1) {
		foreach($_GET as $post => $waarde) {
			$_GET[$post] = trim(strip_tags($waarde));
		}
    }
	if(sizeof($_POST) > 1) {
		foreach($_POST as $post => $waarde) {
			$_POST[$post] = trim(strip_tags($waarde));
		}
    }
	if(sizeof($_SESSION) > 1) {
		foreach($_SESSION as $post => $waarde) {
			$_SESSION[$post] = trim(strip_tags($waarde));
		}
    }