php过滤XSS攻击的函数

PHP文本数据库的搜索方法 searchstr=(“/”.preg_quote($searchstr).”/”);
//$searchstr是查找的关键字 $records=file($file);//获取所有的记录数
//$file是查找的数据文件 $search_reocrds=preg_grep ($searchstr,
$records);//开始查找记录 //$search_reocrds为查找到的记录数
unset($records); if($search_records){
//开始显示记录,写下你自己的处理程序********************
while (list ($key, $val) = each ( $search_records)) { echo “$val “; }
//****************************************************
}

   $found = true; // keep replacing as long as the previous round
replaced something
   while ($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 .= ‘|({0,8}([9|10|13]);)’;
               $pattern .= ‘)*’;
            }
            $pattern .= $ra[$i][$j];
         }
         $pattern .= ‘/i’; 
         $replacement = substr($ra[$i], 0, 2).”.substr($ra[$i], 2);
// add in <> to nerf the tag 
         $val = preg_replace($pattern, $replacement, $val); // filter
out the hex tags 
         if ($val_before == $val) { 
            // no replacements were made, so exit the loop 
            $found = false; 
         } 
      } 
   } 
   return $val; 
}  
?>

      // @ @ search for the hex values
      $val =
preg_replace(‘/([xX]0{0,8}’.dechex(ord($search[$i])).’;?)/i’,
$search[$i], $val); // with a ;
      // @ @ 0{0,7} matches ‘0’ zero to seven times 
      $val = preg_replace(‘/({0,8}’.ord($search[$i]).’;?)/’,
$search[$i], $val); // with a ;
   }

   // now the only remaining whitespace attacks are t, n, and r
   $ra1 = Array(‘javascript’, ‘vbscript’, ‘expression’, ‘applet’,
‘meta’, ‘xml’, ‘blink’, ‘link’, ‘style’, ‘script’, ’embed’, ‘object’,
‘iframe’, ‘frame’, ‘frameset’, ‘ilayer’, ‘layer’, ‘bgsound’, ‘title’,
‘base’);
   $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);

下面的函数可以用来过滤用户的输入,保证输入是XSS安全的。具体如何过滤,可以参看函数内部,也有注释。
复制代码 代码如下:
function RemoveXSS($val) { 
   // remove all non-printable characters. CR(0a) and LF(0b) and TAB(9)
are allowed 
   // this prevents some character re-spacing such as  
   // note that you have to handle splits with n, r, and t later
since they *are* allowed in some inputs 
   $val = preg_replace(‘/([x00-x08,x0b-x0c,x0e-x19])/’,
”, $val); 

   // straight replacements, the user should never need these since
they’re normal characters 
   // this prevents like
图片 1
   $search = ‘abcdefghijklmnopqrstuvwxyz’;
   $search .= ‘ABCDEFGHIJKLMNOPQRSTUVWXYZ’; 
   $search .= ‘1234567890!@#$%^&*()’;
   $search .= ‘~`”;:?+/={}[]-_|’\’;
   for ($i = 0; $i < strlen($search); $i++) {
      // ;? matches the ;, which is optional
      // 0{0,7} matches any padded zeros, which are optional and go up
to 8 chars

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