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phpXSS安全过滤代码

时间:2021-07-01 10:21:17 帮助过:2人阅读

  1. function remove_xss($val) {
  2. // remove all non-printable characters. CR(0a) and LF(0b) and TAB(9) are allowed
  3. // this prevents some character re-spacing such as
  4. // note that you have to handle splits with \n, \r, and \t later since they *are* allowed in some inputs
  5. //http://blog.qita.in
  6. $val = preg_replace('/([\x00-\x08,\x0b-\x0c,\x0e-\x19])/', '', $val);
  7. // straight replacements, the user should never need these since they're normal characters
  8. // this prevents like
  9. $search = 'abcdefghijklmnopqrstuvwxyz';
  10. $search .= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
  11. $search .= '1234567890!@#$%^&*()';
  12. $search .= '~`";:?+/={}[]-_|\'\\';
  13. for ($i = 0; $i < strlen($search); $i++) {
  14. // ;? matches the ;, which is optional
  15. // 0{0,7} matches any padded zeros, which are optional and go up to 8 chars
  16. // @ @ search for the hex values
  17. $val = preg_replace('/(&#[xX]0{0,8}'.dechex(ord($search[$i])).';?)/i', $search[$i], $val); // with a ;
  18. // @ @ 0{0,7} matches '0' zero to seven times
  19. $val = preg_replace('/(?{0,8}'.ord($search[$i]).';?)/', $search[$i], $val); // with a ;
  20. }
  21. // now the only remaining whitespace attacks are \t, \n, and \r
  22. $ra1 = array('javascript', 'vbscript', 'expression', 'applet', 'meta', 'xml', 'blink', 'link', 'style', 'script', 'embed', 'object', 'iframe', 'frame', 'frameset', 'ilayer', 'layer', 'bgsound', 'title', 'base');
  23. $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');
  24. $ra = array_merge($ra1, $ra2);
  25. $found = true; // keep replacing as long as the previous round replaced something
  26. while ($found == true) {
  27. $val_before = $val;
  28. for ($i = 0; $i < sizeof($ra); $i++) {
  29. $pattern = '/';
  30. for ($j = 0; $j < strlen($ra[$i]); $j++) {
  31. if ($j > 0) {
  32. $pattern .= '(';
  33. $pattern .= '(&#[xX]0{0,8}([9ab]);)';
  34. $pattern .= '|';
  35. $pattern .= '|(?{0,8}([9|10|13]);)';
  36. $pattern .= ')*';
  37. }
  38. $pattern .= $ra[$i][$j];
  39. }
  40. $pattern .= '/i';
  41. $replacement = substr($ra[$i], 0, 2).''.substr($ra[$i], 2); // add in <> to nerf the tag
  42. $val = preg_replace($pattern, $replacement, $val); // filter out the hex tags
  43. if ($val_before == $val) {
  44. // no replacements were made, so exit the loop
  45. $found = false;
  46. }
  47. }
  48. }
  49. return $val;
  50. }

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