PHP anti XSS for MySQL queries

antiXSS.php

<?php


function db_query($db_string, $file=null, $line=null) 
{ 
    // One more query.... 
    $db_count = !isset($db_count) ? 1 : $db_count + 1; 

        $clean = ''; 
        $old_pos = 0; 
        $pos = -1; 
        while (true) 
        { 
            $pos = strpos($db_string, '\'', $pos + 1); 
            if ($pos === false) 
                break; 
            $clean .= substr($db_string, $old_pos, $pos - $old_pos); 

            while (true) 
            { 
                $pos1 = strpos($db_string, '\'', $pos + 1); 
                $pos2 = strpos($db_string, '\\', $pos + 1); 
                if ($pos1 === false) 
                    break; 
                elseif ($pos2 == false || $pos2 > $pos1) 
                { 
                    $pos = $pos1; 
                    break; 
                } 

                $pos = $pos2 + 1; 
            } 
            $clean .= ' %s '; 

            $old_pos = $pos + 1; 
        } 
        $clean .= substr($db_string, $old_pos); 
        $clean = trim(strtolower(preg_replace(array('~\s+~s', '~/\*!40001 SQL_NO_CACHE \*/~', '~/\*!40000 USE INDEX \([A-Za-z\_]+?\) \*/~'), array(' ', '', ''), $clean))); 

        // We don't use UNION in SMF, at least so far.  But it's useful for injections. 
        if (strpos($clean, 'union') !== false && preg_match('~(^|[^a-z])union($|[^[a-z])~s', $clean) != 0) 
            $fail = true; 
        // Comments?  We don't use comments in our queries, we leave 'em outside! 
        elseif (strpos($clean, '/*') > 2 || strpos($clean, '--') !== false || strpos($clean, ';') !== false) 
            $fail = true; 
        // Trying to change passwords, slow us down, or something? 
        elseif (strpos($clean, 'sleep') !== false && preg_match('~(^|[^a-z])sleep($|[^[a-z])~s', $clean) != 0) 
            $fail = true; 
        elseif (strpos($clean, 'benchmark') !== false && preg_match('~(^|[^a-z])benchmark($|[^[a-z])~s', $clean) != 0) 
            $fail = true; 
        // Sub selects?  We don't use those either. 
        elseif (preg_match('~\([^)]*?select~s', $clean) != 0) 
            $fail = true; 

        if (!empty($fail)) 
        { 
          die('Hacking attempt...<br />file:"'.$file .'"<br />line:"'.$line.'"'); 
        } 

        //echo $db_string.'<br />'. 
    $ret = mysql_query($db_string); 
    if ($ret === false && $file !== false){ 
          die('MySQL error:<br />file:"'.$file .'"<br />line:"'.$line.'"'); 
} 
    return $ret; 
} 

function noXSS($val) { 
   $val = preg_replace('/([\x00-\x08,\x0b-\x0c,\x0e-\x19])/', '', $val); 
   $search  = 'abcdefghijklmnopqrstuvwxyz'; 
   $search .= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'; 
   $search .= '1234567890!@#$%^&*()'; 
   $search .= '~`";:?+/={}[]-_|\'\\'; 
   for ($i = 0; $i < strlen($search); $i++) { 
      $val = preg_replace('/(&#[xX]0{0,8}'.dechex(ord($search[$i])).';?)/i', $search[$i], $val); // with a ;   
      $val = preg_replace('/(&#0{0,8}'.ord($search[$i]).';?)/', $search[$i], $val); // with a ;   
   }; 
   $ra1 = Array('javascript', 'vbscript', 'expression', 'applet', 'meta', 'xml', 'blink', 'link', 'style', 'script', 'embed', 'object', 'iframe', 'frame', 'frameset', 'ilayer', 'layer', 'bgsound', 'title', 'base','union');   
   $ra2 = Array('onabort', 'onactivate', 'onafterprint', 'onafterupdate', 'onbeforeactivate', 'onbeforecopy', 'onbeforecut', 'onbeforedeactivate', 'onbeforeeditfocus', 'onbeforepaste', 'onbeforeprint', 'onbeforeunload', 'onbeforeupdate', 'onblur', 'onbounce', 'oncellchange', 'onchange', 'onclick', 'oncontextmenu', 'oncontrolselect', 'oncopy', 'oncut', 'ondataavailable', 'ondatasetchanged', 'ondatasetcomplete', 'ondblclick', 'ondeactivate', 'ondrag', 'ondragend', 'ondragenter', 'ondragleave', 'ondragover', 'ondragstart', 'ondrop', 'onerror', 'onerrorupdate', 'onfilterchange', 'onfinish', 'onfocus', 'onfocusin', 'onfocusout', 'onhelp', 'onkeydown', 'onkeypress', 'onkeyup', 'onlayoutcomplete', 'onload', 'onlosecapture', 'onmousedown', 'onmouseenter', 'onmouseleave', 'onmousemove', 'onmouseout', 'onmouseover', 'onmouseup', 'onmousewheel', 'onmove', 'onmoveend', 'onmovestart', 'onpaste', 'onpropertychange', 'onreadystatechange', 'onreset', 'onresize', 'onresizeend', 'onresizestart', 'onrowenter', 'onrowexit', 'onrowsdelete', 'onrowsinserted', 'onscroll', 'onselect', 'onselectionchange', 'onselectstart', 'onstart', 'onstop', 'onsubmit', 'onunload');   
   $ra = array_merge($ra1, $ra2); 
      
   $found = true; 
   while ($found == true) { 
      $val_before = $val; 
      for ($i = 0; $i < sizeof($ra); $i++) { 
         $pattern = '/'; 
         for ($j = 0; $j < strlen($ra[$i]); $j++) { 
            if ($j > 0) { 
               $pattern .= '('; 
               $pattern .= '(&#[xX]0{0,8}([9ab]);)'; 
               $pattern .= '|'; 
               $pattern .= '|(&#0{0,8}([9|10|13]);)'; 
               $pattern .= ')*'; 
            } 
            $pattern .= $ra[$i][$j]; 
         } 
         $pattern .= '/i'; 
         $replacement = substr($ra[$i], 0, 2).'<x>'.substr($ra[$i], 2); // add in <> to nerf the tag 
         $val = preg_replace($pattern, $replacement, $val); // filter out the hex tags 
         if ($val_before == $val) { 
            $found = false; 
         }; 
      }; 
   }; 
   return mysql_escape_string($val); 
}  

?>