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1160 lines
38 KiB
1160 lines
38 KiB
<?php
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/**
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* htmlfilter.inc
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* ---------------
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* This set of functions allows you to filter html in order to remove
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* any malicious tags from it. Useful in cases when you need to filter
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* user input for any cross-site-scripting attempts.
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*
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* Copyright (C) 2002-2004 by Duke University
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
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* 02110-1301 USA
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*
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* @Author Konstantin Riabitsev <icon@linux.duke.edu>
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* @Author Jim Jagielski <jim@jaguNET.com / jimjag@gmail.com>
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* @Version 1.1 ($Date$)
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*/
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/**
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* This function returns the final tag out of the tag name, an array
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* of attributes, and the type of the tag. This function is called by
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* tln_sanitize internally.
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*
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* @param string $tagname the name of the tag.
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* @param array $attary the array of attributes and their values
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* @param integer $tagtype The type of the tag (see in comments).
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* @return string A string with the final tag representation.
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*/
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function tln_tagprint($tagname, $attary, $tagtype)
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{
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if ($tagtype == 2) {
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$fulltag = '</' . $tagname . '>';
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} else {
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$fulltag = '<' . $tagname;
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if (is_array($attary) && sizeof($attary)) {
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$atts = array();
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foreach($attary as $attname => $attvalue) {
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array_push($atts, "$attname=$attvalue");
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}
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$fulltag .= ' ' . join(' ', $atts);
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}
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if ($tagtype == 3) {
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$fulltag .= ' /';
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}
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$fulltag .= '>';
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}
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return $fulltag;
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}
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/**
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* A small helper function to use with array_walk. Modifies a by-ref
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* value and makes it lowercase.
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*
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* @param string $val a value passed by-ref.
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* @return void since it modifies a by-ref value.
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*/
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function tln_casenormalize(&$val)
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{
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$val = strtolower($val);
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}
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/**
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* This function skips any whitespace from the current position within
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* a string and to the next non-whitespace value.
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*
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* @param string $body the string
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* @param integer $offset the offset within the string where we should start
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* looking for the next non-whitespace character.
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* @return integer the location within the $body where the next
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* non-whitespace char is located.
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*/
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function tln_skipspace($body, $offset)
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{
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preg_match('/^(\s*)/s', substr($body, $offset), $matches);
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if (sizeof($matches[1])) {
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$count = strlen($matches[1]);
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$offset += $count;
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}
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return $offset;
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}
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/**
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* This function looks for the next character within a string. It's
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* really just a glorified "strpos", except it catches the failures
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* nicely.
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*
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* @param string $body The string to look for needle in.
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* @param integer $offset Start looking from this position.
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* @param string $needle The character/string to look for.
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* @return integer location of the next occurrence of the needle, or
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* strlen($body) if needle wasn't found.
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*/
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function tln_findnxstr($body, $offset, $needle)
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{
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$pos = strpos($body, $needle, $offset);
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if ($pos === false) {
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$pos = strlen($body);
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}
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return $pos;
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}
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/**
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* This function takes a PCRE-style regexp and tries to match it
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* within the string.
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*
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* @param string $body The string to look for needle in.
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* @param integer $offset Start looking from here.
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* @param string $reg A PCRE-style regex to match.
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* @return array|boolean Returns a false if no matches found, or an array
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* with the following members:
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* - integer with the location of the match within $body
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* - string with whatever content between offset and the match
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* - string with whatever it is we matched
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*/
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function tln_findnxreg($body, $offset, $reg)
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{
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$matches = array();
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$retarr = array();
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$preg_rule = '%^(.*?)(' . $reg . ')%s';
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preg_match($preg_rule, substr($body, $offset), $matches);
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if (!isset($matches[0]) || !$matches[0]) {
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$retarr = false;
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} else {
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$retarr[0] = $offset + strlen($matches[1]);
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$retarr[1] = $matches[1];
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$retarr[2] = $matches[2];
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}
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return $retarr;
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}
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/**
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* This function looks for the next tag.
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*
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* @param string $body String where to look for the next tag.
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* @param integer $offset Start looking from here.
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* @return array|boolean false if no more tags exist in the body, or
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* an array with the following members:
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* - string with the name of the tag
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* - array with attributes and their values
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* - integer with tag type (1, 2, or 3)
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* - integer where the tag starts (starting "<")
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* - integer where the tag ends (ending ">")
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* first three members will be false, if the tag is invalid.
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*/
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function tln_getnxtag($body, $offset)
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{
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if ($offset > strlen($body)) {
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return false;
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}
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$lt = tln_findnxstr($body, $offset, '<');
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if ($lt == strlen($body)) {
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return false;
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}
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/**
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* We are here:
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* blah blah <tag attribute="value">
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* \---------^
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*/
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$pos = tln_skipspace($body, $lt + 1);
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if ($pos >= strlen($body)) {
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return array(false, false, false, $lt, strlen($body));
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}
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/**
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* There are 3 kinds of tags:
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* 1. Opening tag, e.g.:
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* <a href="blah">
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* 2. Closing tag, e.g.:
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* </a>
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* 3. XHTML-style content-less tag, e.g.:
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* <img src="blah"/>
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*/
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switch (substr($body, $pos, 1)) {
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case '/':
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$tagtype = 2;
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$pos++;
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break;
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case '!':
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/**
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* A comment or an SGML declaration.
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*/
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if (substr($body, $pos + 1, 2) == '--') {
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$gt = strpos($body, '-->', $pos);
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if ($gt === false) {
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$gt = strlen($body);
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} else {
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$gt += 2;
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}
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return array(false, false, false, $lt, $gt);
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} else {
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$gt = tln_findnxstr($body, $pos, '>');
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return array(false, false, false, $lt, $gt);
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}
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break;
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default:
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/**
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* Assume tagtype 1 for now. If it's type 3, we'll switch values
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* later.
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*/
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$tagtype = 1;
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break;
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}
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/**
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* Look for next [\W-_], which will indicate the end of the tag name.
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*/
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$regary = tln_findnxreg($body, $pos, '[^\w\-_]');
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if ($regary == false) {
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return array(false, false, false, $lt, strlen($body));
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}
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list($pos, $tagname, $match) = $regary;
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$tagname = strtolower($tagname);
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/**
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* $match can be either of these:
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* '>' indicating the end of the tag entirely.
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* '\s' indicating the end of the tag name.
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* '/' indicating that this is type-3 xhtml tag.
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*
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* Whatever else we find there indicates an invalid tag.
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*/
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switch ($match) {
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case '/':
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/**
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* This is an xhtml-style tag with a closing / at the
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* end, like so: <img src="blah"/>. Check if it's followed
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* by the closing bracket. If not, then this tag is invalid
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*/
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if (substr($body, $pos, 2) == '/>') {
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$pos++;
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$tagtype = 3;
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} else {
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$gt = tln_findnxstr($body, $pos, '>');
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$retary = array(false, false, false, $lt, $gt);
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return $retary;
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}
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//intentional fall-through
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case '>':
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return array($tagname, false, $tagtype, $lt, $pos);
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break;
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default:
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/**
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* Check if it's whitespace
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*/
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if (!preg_match('/\s/', $match)) {
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/**
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* This is an invalid tag! Look for the next closing ">".
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*/
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$gt = tln_findnxstr($body, $lt, '>');
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return array(false, false, false, $lt, $gt);
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}
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break;
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}
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/**
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* At this point we're here:
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* <tagname attribute='blah'>
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* \-------^
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*
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* At this point we loop in order to find all attributes.
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*/
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$attary = array();
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while ($pos <= strlen($body)) {
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$pos = tln_skipspace($body, $pos);
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if ($pos == strlen($body)) {
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/**
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* Non-closed tag.
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*/
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return array(false, false, false, $lt, $pos);
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}
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/**
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* See if we arrived at a ">" or "/>", which means that we reached
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* the end of the tag.
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*/
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$matches = array();
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if (preg_match('%^(\s*)(>|/>)%s', substr($body, $pos), $matches)) {
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/**
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* Yep. So we did.
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*/
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$pos += strlen($matches[1]);
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if ($matches[2] == '/>') {
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$tagtype = 3;
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$pos++;
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}
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return array($tagname, $attary, $tagtype, $lt, $pos);
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}
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/**
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* There are several types of attributes, with optional
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* [:space:] between members.
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* Type 1:
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* attrname[:space:]=[:space:]'CDATA'
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* Type 2:
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* attrname[:space:]=[:space:]"CDATA"
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* Type 3:
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* attr[:space:]=[:space:]CDATA
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* Type 4:
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* attrname
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*
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* We leave types 1 and 2 the same, type 3 we check for
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* '"' and convert to """ if needed, then wrap in
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* double quotes. Type 4 we convert into:
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* attrname="yes".
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*/
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$regary = tln_findnxreg($body, $pos, '[^\w\-_]');
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if ($regary == false) {
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/**
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* Looks like body ended before the end of tag.
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*/
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return array(false, false, false, $lt, strlen($body));
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}
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list($pos, $attname, $match) = $regary;
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$attname = strtolower($attname);
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/**
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* We arrived at the end of attribute name. Several things possible
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* here:
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* '>' means the end of the tag and this is attribute type 4
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* '/' if followed by '>' means the same thing as above
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* '\s' means a lot of things -- look what it's followed by.
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* anything else means the attribute is invalid.
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*/
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switch ($match) {
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case '/':
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/**
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* This is an xhtml-style tag with a closing / at the
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* end, like so: <img src="blah"/>. Check if it's followed
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* by the closing bracket. If not, then this tag is invalid
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*/
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if (substr($body, $pos, 2) == '/>') {
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$pos++;
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$tagtype = 3;
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} else {
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$gt = tln_findnxstr($body, $pos, '>');
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$retary = array(false, false, false, $lt, $gt);
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return $retary;
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}
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//intentional fall-through
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case '>':
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$attary{$attname} = '"yes"';
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return array($tagname, $attary, $tagtype, $lt, $pos);
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break;
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default:
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/**
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* Skip whitespace and see what we arrive at.
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*/
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$pos = tln_skipspace($body, $pos);
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$char = substr($body, $pos, 1);
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/**
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* Two things are valid here:
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* '=' means this is attribute type 1 2 or 3.
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* \w means this was attribute type 4.
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* anything else we ignore and re-loop. End of tag and
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* invalid stuff will be caught by our checks at the beginning
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* of the loop.
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*/
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if ($char == '=') {
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$pos++;
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$pos = tln_skipspace($body, $pos);
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/**
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* Here are 3 possibilities:
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* "'" attribute type 1
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* '"' attribute type 2
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* everything else is the content of tag type 3
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*/
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$quot = substr($body, $pos, 1);
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if ($quot == '\'') {
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$regary = tln_findnxreg($body, $pos + 1, '\'');
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if ($regary == false) {
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return array(false, false, false, $lt, strlen($body));
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}
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list($pos, $attval, $match) = $regary;
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$pos++;
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$attary{$attname} = '\'' . $attval . '\'';
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} elseif ($quot == '"') {
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$regary = tln_findnxreg($body, $pos + 1, '\"');
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if ($regary == false) {
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return array(false, false, false, $lt, strlen($body));
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}
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list($pos, $attval, $match) = $regary;
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$pos++;
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$attary{$attname} = '"' . $attval . '"';
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} else {
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/**
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* These are hateful. Look for \s, or >.
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*/
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$regary = tln_findnxreg($body, $pos, '[\s>]');
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if ($regary == false) {
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return array(false, false, false, $lt, strlen($body));
|
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}
|
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list($pos, $attval, $match) = $regary;
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/**
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* If it's ">" it will be caught at the top.
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*/
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$attval = preg_replace('/\"/s', '"', $attval);
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$attary{$attname} = '"' . $attval . '"';
|
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}
|
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} elseif (preg_match('|[\w/>]|', $char)) {
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/**
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* That was attribute type 4.
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*/
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$attary{$attname} = '"yes"';
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} else {
|
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/**
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* An illegal character. Find next '>' and return.
|
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*/
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$gt = tln_findnxstr($body, $pos, '>');
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return array(false, false, false, $lt, $gt);
|
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}
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break;
|
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}
|
|
}
|
|
/**
|
|
* The fact that we got here indicates that the tag end was never
|
|
* found. Return invalid tag indication so it gets stripped.
|
|
*/
|
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return array(false, false, false, $lt, strlen($body));
|
|
}
|
|
|
|
/**
|
|
* Translates entities into literal values so they can be checked.
|
|
*
|
|
* @param string $attvalue the by-ref value to check.
|
|
* @param string $regex the regular expression to check against.
|
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* @param boolean $hex whether the entities are hexadecimal.
|
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* @return boolean True or False depending on whether there were matches.
|
|
*/
|
|
function tln_deent(&$attvalue, $regex, $hex = false)
|
|
{
|
|
preg_match_all($regex, $attvalue, $matches);
|
|
if (is_array($matches) && sizeof($matches[0]) > 0) {
|
|
$repl = array();
|
|
for ($i = 0; $i < sizeof($matches[0]); $i++) {
|
|
$numval = $matches[1][$i];
|
|
if ($hex) {
|
|
$numval = hexdec($numval);
|
|
}
|
|
$repl{$matches[0][$i]} = chr($numval);
|
|
}
|
|
$attvalue = strtr($attvalue, $repl);
|
|
return true;
|
|
} else {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* This function checks attribute values for entity-encoded values
|
|
* and returns them translated into 8-bit strings so we can run
|
|
* checks on them.
|
|
*
|
|
* @param string $attvalue A string to run entity check against.
|
|
*/
|
|
function tln_defang(&$attvalue)
|
|
{
|
|
/**
|
|
* Skip this if there aren't ampersands or backslashes.
|
|
*/
|
|
if (strpos($attvalue, '&') === false
|
|
&& strpos($attvalue, '\\') === false
|
|
) {
|
|
return;
|
|
}
|
|
do {
|
|
$m = false;
|
|
$m = $m || tln_deent($attvalue, '/\�*(\d+);*/s');
|
|
$m = $m || tln_deent($attvalue, '/\�*((\d|[a-f])+);*/si', true);
|
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$m = $m || tln_deent($attvalue, '/\\\\(\d+)/s', true);
|
|
} while ($m == true);
|
|
$attvalue = stripslashes($attvalue);
|
|
}
|
|
|
|
/**
|
|
* Kill any tabs, newlines, or carriage returns. Our friends the
|
|
* makers of the browser with 95% market value decided that it'd
|
|
* be funny to make "java[tab]script" be just as good as "javascript".
|
|
*
|
|
* @param string $attvalue The attribute value before extraneous spaces removed.
|
|
*/
|
|
function tln_unspace(&$attvalue)
|
|
{
|
|
if (strcspn($attvalue, "\t\r\n\0 ") != strlen($attvalue)) {
|
|
$attvalue = str_replace(
|
|
array("\t", "\r", "\n", "\0", " "),
|
|
array('', '', '', '', ''),
|
|
$attvalue
|
|
);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* This function runs various checks against the attributes.
|
|
*
|
|
* @param string $tagname String with the name of the tag.
|
|
* @param array $attary Array with all tag attributes.
|
|
* @param array $rm_attnames See description for tln_sanitize
|
|
* @param array $bad_attvals See description for tln_sanitize
|
|
* @param array $add_attr_to_tag See description for tln_sanitize
|
|
* @param string $trans_image_path
|
|
* @param boolean $block_external_images
|
|
* @return array with modified attributes.
|
|
*/
|
|
function tln_fixatts(
|
|
$tagname,
|
|
$attary,
|
|
$rm_attnames,
|
|
$bad_attvals,
|
|
$add_attr_to_tag,
|
|
$trans_image_path,
|
|
$block_external_images
|
|
) {
|
|
foreach($attary as $attname => $attvalue) {
|
|
/**
|
|
* See if this attribute should be removed.
|
|
*/
|
|
foreach ($rm_attnames as $matchtag => $matchattrs) {
|
|
if (preg_match($matchtag, $tagname)) {
|
|
foreach ($matchattrs as $matchattr) {
|
|
if (preg_match($matchattr, $attname)) {
|
|
unset($attary{$attname});
|
|
continue;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
/**
|
|
* Remove any backslashes, entities, or extraneous whitespace.
|
|
*/
|
|
$oldattvalue = $attvalue;
|
|
tln_defang($attvalue);
|
|
if ($attname == 'style' && $attvalue !== $oldattvalue) {
|
|
$attvalue = "idiocy";
|
|
$attary{$attname} = $attvalue;
|
|
}
|
|
tln_unspace($attvalue);
|
|
|
|
/**
|
|
* Now let's run checks on the attvalues.
|
|
* I don't expect anyone to comprehend this. If you do,
|
|
* get in touch with me so I can drive to where you live and
|
|
* shake your hand personally. :)
|
|
*/
|
|
foreach ($bad_attvals as $matchtag => $matchattrs) {
|
|
if (preg_match($matchtag, $tagname)) {
|
|
foreach ($matchattrs as $matchattr => $valary) {
|
|
if (preg_match($matchattr, $attname)) {
|
|
/**
|
|
* There are two arrays in valary.
|
|
* First is matches.
|
|
* Second one is replacements
|
|
*/
|
|
list($valmatch, $valrepl) = $valary;
|
|
$newvalue = preg_replace($valmatch, $valrepl, $attvalue);
|
|
if ($newvalue != $attvalue) {
|
|
$attary{$attname} = $newvalue;
|
|
$attvalue = $newvalue;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if ($attname == 'style') {
|
|
if (preg_match('/[\0-\37\200-\377]+/', $attvalue)) {
|
|
$attary{$attname} = '"disallowed character"';
|
|
}
|
|
preg_match_all("/url\s*\((.+)\)/si", $attvalue, $aMatch);
|
|
if (count($aMatch)) {
|
|
foreach($aMatch[1] as $sMatch) {
|
|
$urlvalue = $sMatch;
|
|
tln_fixurl($attname, $urlvalue, $trans_image_path, $block_external_images);
|
|
$attary{$attname} = str_replace($sMatch, $urlvalue, $attvalue);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
/**
|
|
* See if we need to append any attributes to this tag.
|
|
*/
|
|
foreach ($add_attr_to_tag as $matchtag => $addattary) {
|
|
if (preg_match($matchtag, $tagname)) {
|
|
$attary = array_merge($attary, $addattary);
|
|
}
|
|
}
|
|
return $attary;
|
|
}
|
|
|
|
function tln_fixurl($attname, &$attvalue, $trans_image_path, $block_external_images)
|
|
{
|
|
$sQuote = '"';
|
|
$attvalue = trim($attvalue);
|
|
if ($attvalue && ($attvalue[0] =='"'|| $attvalue[0] == "'")) {
|
|
// remove the double quotes
|
|
$sQuote = $attvalue[0];
|
|
$attvalue = trim(substr($attvalue,1,-1));
|
|
}
|
|
|
|
/**
|
|
* Replace empty src tags with the blank image. src is only used
|
|
* for frames, images, and image inputs. Doing a replace should
|
|
* not affect them working as should be, however it will stop
|
|
* IE from being kicked off when src for img tags are not set
|
|
*/
|
|
if ($attvalue == '') {
|
|
$attvalue = $sQuote . $trans_image_path . $sQuote;
|
|
} else {
|
|
// first, disallow 8 bit characters and control characters
|
|
if (preg_match('/[\0-\37\200-\377]+/',$attvalue)) {
|
|
switch ($attname) {
|
|
case 'href':
|
|
$attvalue = $sQuote . 'http://invalid-stuff-detected.example.com' . $sQuote;
|
|
break;
|
|
default:
|
|
$attvalue = $sQuote . $trans_image_path . $sQuote;
|
|
break;
|
|
}
|
|
} else {
|
|
$aUrl = parse_url($attvalue);
|
|
if (isset($aUrl['scheme'])) {
|
|
switch(strtolower($aUrl['scheme'])) {
|
|
case 'mailto':
|
|
case 'http':
|
|
case 'https':
|
|
case 'ftp':
|
|
if ($attname != 'href') {
|
|
if ($block_external_images == true) {
|
|
$attvalue = $sQuote . $trans_image_path . $sQuote;
|
|
} else {
|
|
if (!isset($aUrl['path'])) {
|
|
$attvalue = $sQuote . $trans_image_path . $sQuote;
|
|
}
|
|
}
|
|
} else {
|
|
$attvalue = $sQuote . $attvalue . $sQuote;
|
|
}
|
|
break;
|
|
case 'outbind':
|
|
$attvalue = $sQuote . $attvalue . $sQuote;
|
|
break;
|
|
case 'cid':
|
|
$attvalue = $sQuote . $attvalue . $sQuote;
|
|
break;
|
|
default:
|
|
$attvalue = $sQuote . $trans_image_path . $sQuote;
|
|
break;
|
|
}
|
|
} else {
|
|
if (!isset($aUrl['path']) || $aUrl['path'] != $trans_image_path) {
|
|
$$attvalue = $sQuote . $trans_image_path . $sQuote;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
function tln_fixstyle($body, $pos, $trans_image_path, $block_external_images)
|
|
{
|
|
// workaround for </style> in between comments
|
|
$content = '';
|
|
$sToken = '';
|
|
$bSucces = false;
|
|
$bEndTag = false;
|
|
for ($i=$pos,$iCount=strlen($body);$i<$iCount;++$i) {
|
|
$char = $body{$i};
|
|
switch ($char) {
|
|
case '<':
|
|
$sToken = $char;
|
|
break;
|
|
case '/':
|
|
if ($sToken == '<') {
|
|
$sToken .= $char;
|
|
$bEndTag = true;
|
|
} else {
|
|
$content .= $char;
|
|
}
|
|
break;
|
|
case '>':
|
|
if ($bEndTag) {
|
|
$sToken .= $char;
|
|
if (preg_match('/\<\/\s*style\s*\>/i',$sToken,$aMatch)) {
|
|
$newpos = $i + 1;
|
|
$bSucces = true;
|
|
break 2;
|
|
} else {
|
|
$content .= $sToken;
|
|
}
|
|
$bEndTag = false;
|
|
} else {
|
|
$content .= $char;
|
|
}
|
|
break;
|
|
case '!':
|
|
if ($sToken == '<') {
|
|
// possible comment
|
|
if (isset($body{$i+2}) && substr($body,$i,3) == '!--') {
|
|
$i = strpos($body,'-->',$i+3);
|
|
if ($i === false) { // no end comment
|
|
$i = strlen($body);
|
|
}
|
|
$sToken = '';
|
|
}
|
|
} else {
|
|
$content .= $char;
|
|
}
|
|
break;
|
|
default:
|
|
if ($bEndTag) {
|
|
$sToken .= $char;
|
|
} else {
|
|
$content .= $char;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
if ($bSucces == FALSE){
|
|
return array(FALSE, strlen($body));
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
* First look for general BODY style declaration, which would be
|
|
* like so:
|
|
* body {background: blah-blah}
|
|
* and change it to .bodyclass so we can just assign it to a <div>
|
|
*/
|
|
$content = preg_replace("|body(\s*\{.*?\})|si", ".bodyclass\\1", $content);
|
|
|
|
/**
|
|
* Fix url('blah') declarations.
|
|
*/
|
|
// $content = preg_replace("|url\s*\(\s*([\'\"])\s*\S+script\s*:.*?([\'\"])\s*\)|si",
|
|
// "url(\\1$trans_image_path\\2)", $content);
|
|
|
|
// first check for 8bit sequences and disallowed control characters
|
|
if (preg_match('/[\16-\37\200-\377]+/',$content)) {
|
|
$content = '<!-- style block removed by html filter due to presence of 8bit characters -->';
|
|
return array($content, $newpos);
|
|
}
|
|
|
|
// remove @import line
|
|
$content = preg_replace("/^\s*(@import.*)$/mi","\n<!-- @import rules forbidden -->\n",$content);
|
|
|
|
$content = preg_replace("/(\\\\)?u(\\\\)?r(\\\\)?l(\\\\)?/i", 'url', $content);
|
|
preg_match_all("/url\s*\((.+)\)/si",$content,$aMatch);
|
|
if (count($aMatch)) {
|
|
$aValue = $aReplace = array();
|
|
foreach($aMatch[1] as $sMatch) {
|
|
// url value
|
|
$urlvalue = $sMatch;
|
|
tln_fixurl('style',$urlvalue, $trans_image_path, $block_external_images);
|
|
$aValue[] = $sMatch;
|
|
$aReplace[] = $urlvalue;
|
|
}
|
|
$content = str_replace($aValue,$aReplace,$content);
|
|
}
|
|
|
|
/**
|
|
* Remove any backslashes, entities, and extraneous whitespace.
|
|
*/
|
|
$contentTemp = $content;
|
|
tln_defang($contentTemp);
|
|
tln_unspace($contentTemp);
|
|
|
|
$match = array('/\/\*.*\*\//',
|
|
'/expression/i',
|
|
'/behaviou*r/i',
|
|
'/binding/i',
|
|
'/include-source/i',
|
|
'/javascript/i',
|
|
'/script/i',
|
|
'/position/i');
|
|
$replace = array('','idiocy', 'idiocy', 'idiocy', 'idiocy', 'idiocy', 'idiocy', '');
|
|
$contentNew = preg_replace($match, $replace, $contentTemp);
|
|
if ($contentNew !== $contentTemp) {
|
|
$content = $contentNew;
|
|
}
|
|
return array($content, $newpos);
|
|
}
|
|
|
|
function tln_body2div($attary, $trans_image_path)
|
|
{
|
|
$divattary = array('class' => "'bodyclass'");
|
|
$text = '#000000';
|
|
$has_bgc_stl = $has_txt_stl = false;
|
|
$styledef = '';
|
|
if (is_array($attary) && sizeof($attary) > 0){
|
|
foreach ($attary as $attname=>$attvalue){
|
|
$quotchar = substr($attvalue, 0, 1);
|
|
$attvalue = str_replace($quotchar, "", $attvalue);
|
|
switch ($attname){
|
|
case 'background':
|
|
$styledef .= "background-image: url('$trans_image_path'); ";
|
|
break;
|
|
case 'bgcolor':
|
|
$has_bgc_stl = true;
|
|
$styledef .= "background-color: $attvalue; ";
|
|
break;
|
|
case 'text':
|
|
$has_txt_stl = true;
|
|
$styledef .= "color: $attvalue; ";
|
|
break;
|
|
}
|
|
}
|
|
// Outlook defines a white bgcolor and no text color. This can lead to
|
|
// white text on a white bg with certain themes.
|
|
if ($has_bgc_stl && !$has_txt_stl) {
|
|
$styledef .= "color: $text; ";
|
|
}
|
|
if (strlen($styledef) > 0){
|
|
$divattary{"style"} = "\"$styledef\"";
|
|
}
|
|
}
|
|
return $divattary;
|
|
}
|
|
|
|
/**
|
|
*
|
|
* @param string $body The HTML you wish to filter
|
|
* @param array $tag_list see description above
|
|
* @param array $rm_tags_with_content see description above
|
|
* @param array $self_closing_tags see description above
|
|
* @param boolean $force_tag_closing see description above
|
|
* @param array $rm_attnames see description above
|
|
* @param array $bad_attvals see description above
|
|
* @param array $add_attr_to_tag see description above
|
|
* @param string $trans_image_path
|
|
* @param boolean $block_external_images
|
|
|
|
* @return string Sanitized html safe to show on your pages.
|
|
*/
|
|
function tln_sanitize(
|
|
$body,
|
|
$tag_list,
|
|
$rm_tags_with_content,
|
|
$self_closing_tags,
|
|
$force_tag_closing,
|
|
$rm_attnames,
|
|
$bad_attvals,
|
|
$add_attr_to_tag,
|
|
$trans_image_path,
|
|
$block_external_images
|
|
) {
|
|
/**
|
|
* Normalize rm_tags and rm_tags_with_content.
|
|
*/
|
|
$rm_tags = array_shift($tag_list);
|
|
@array_walk($tag_list, 'tln_casenormalize');
|
|
@array_walk($rm_tags_with_content, 'tln_casenormalize');
|
|
@array_walk($self_closing_tags, 'tln_casenormalize');
|
|
/**
|
|
* See if tag_list is of tags to remove or tags to allow.
|
|
* false means remove these tags
|
|
* true means allow these tags
|
|
*/
|
|
$curpos = 0;
|
|
$open_tags = array();
|
|
$trusted = "<!-- begin tln_sanitized html -->\n";
|
|
$skip_content = false;
|
|
/**
|
|
* Take care of netscape's stupid javascript entities like
|
|
* &{alert('boo')};
|
|
*/
|
|
$body = preg_replace('/&(\{.*?\};)/si', '&\\1', $body);
|
|
while (($curtag = tln_getnxtag($body, $curpos)) != false) {
|
|
list($tagname, $attary, $tagtype, $lt, $gt) = $curtag;
|
|
$free_content = substr($body, $curpos, $lt-$curpos);
|
|
/**
|
|
* Take care of <style>
|
|
*/
|
|
if ($tagname == "style" && $tagtype == 1){
|
|
list($free_content, $curpos) =
|
|
tln_fixstyle($body, $gt+1, $trans_image_path, $block_external_images);
|
|
if ($free_content != FALSE){
|
|
if ( !empty($attary) ) {
|
|
$attary = tln_fixatts($tagname,
|
|
$attary,
|
|
$rm_attnames,
|
|
$bad_attvals,
|
|
$add_attr_to_tag,
|
|
$trans_image_path,
|
|
$block_external_images
|
|
);
|
|
}
|
|
$trusted .= tln_tagprint($tagname, $attary, $tagtype);
|
|
$trusted .= $free_content;
|
|
$trusted .= tln_tagprint($tagname, null, 2);
|
|
}
|
|
continue;
|
|
}
|
|
if ($skip_content == false){
|
|
$trusted .= $free_content;
|
|
}
|
|
if ($tagname != false) {
|
|
if ($tagtype == 2) {
|
|
if ($skip_content == $tagname) {
|
|
/**
|
|
* Got to the end of tag we needed to remove.
|
|
*/
|
|
$tagname = false;
|
|
$skip_content = false;
|
|
} else {
|
|
if ($skip_content == false) {
|
|
if ($tagname == "body") {
|
|
$tagname = "div";
|
|
}
|
|
if (isset($open_tags{$tagname}) &&
|
|
$open_tags{$tagname} > 0
|
|
) {
|
|
$open_tags{$tagname}--;
|
|
} else {
|
|
$tagname = false;
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
/**
|
|
* $rm_tags_with_content
|
|
*/
|
|
if ($skip_content == false) {
|
|
/**
|
|
* See if this is a self-closing type and change
|
|
* tagtype appropriately.
|
|
*/
|
|
if ($tagtype == 1
|
|
&& in_array($tagname, $self_closing_tags)
|
|
) {
|
|
$tagtype = 3;
|
|
}
|
|
/**
|
|
* See if we should skip this tag and any content
|
|
* inside it.
|
|
*/
|
|
if ($tagtype == 1
|
|
&& in_array($tagname, $rm_tags_with_content)
|
|
) {
|
|
$skip_content = $tagname;
|
|
} else {
|
|
if (($rm_tags == false
|
|
&& in_array($tagname, $tag_list)) ||
|
|
($rm_tags == true
|
|
&& !in_array($tagname, $tag_list))
|
|
) {
|
|
$tagname = false;
|
|
} else {
|
|
/**
|
|
* Convert body into div.
|
|
*/
|
|
if ($tagname == "body"){
|
|
$tagname = "div";
|
|
$attary = tln_body2div($attary, $trans_image_path);
|
|
}
|
|
if ($tagtype == 1) {
|
|
if (isset($open_tags{$tagname})) {
|
|
$open_tags{$tagname}++;
|
|
} else {
|
|
$open_tags{$tagname} = 1;
|
|
}
|
|
}
|
|
/**
|
|
* This is where we run other checks.
|
|
*/
|
|
if (is_array($attary) && sizeof($attary) > 0) {
|
|
$attary = tln_fixatts(
|
|
$tagname,
|
|
$attary,
|
|
$rm_attnames,
|
|
$bad_attvals,
|
|
$add_attr_to_tag,
|
|
$trans_image_path,
|
|
$block_external_images
|
|
);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if ($tagname != false && $skip_content == false) {
|
|
$trusted .= tln_tagprint($tagname, $attary, $tagtype);
|
|
}
|
|
}
|
|
$curpos = $gt + 1;
|
|
}
|
|
$trusted .= substr($body, $curpos, strlen($body) - $curpos);
|
|
if ($force_tag_closing == true) {
|
|
foreach ($open_tags as $tagname => $opentimes) {
|
|
while ($opentimes > 0) {
|
|
$trusted .= '</' . $tagname . '>';
|
|
$opentimes--;
|
|
}
|
|
}
|
|
$trusted .= "\n";
|
|
}
|
|
$trusted .= "<!-- end tln_sanitized html -->\n";
|
|
return $trusted;
|
|
}
|
|
|
|
//
|
|
// Use the nifty htmlfilter library
|
|
//
|
|
|
|
|
|
function HTMLFilter($body, $trans_image_path, $block_external_images = false)
|
|
{
|
|
|
|
$tag_list = array(
|
|
false,
|
|
"object",
|
|
"meta",
|
|
"html",
|
|
"head",
|
|
"base",
|
|
"link",
|
|
"frame",
|
|
"iframe",
|
|
"plaintext",
|
|
"marquee"
|
|
);
|
|
|
|
$rm_tags_with_content = array(
|
|
"script",
|
|
"applet",
|
|
"embed",
|
|
"title",
|
|
"frameset",
|
|
"xmp",
|
|
"xml"
|
|
);
|
|
|
|
$self_closing_tags = array(
|
|
"img",
|
|
"br",
|
|
"hr",
|
|
"input",
|
|
"outbind"
|
|
);
|
|
|
|
$force_tag_closing = true;
|
|
|
|
$rm_attnames = array(
|
|
"/.*/" =>
|
|
array(
|
|
// "/target/i",
|
|
"/^on.*/i",
|
|
"/^dynsrc/i",
|
|
"/^data.*/i",
|
|
"/^lowsrc.*/i"
|
|
)
|
|
);
|
|
|
|
$bad_attvals = array(
|
|
"/.*/" =>
|
|
array(
|
|
"/^src|background/i" =>
|
|
array(
|
|
array(
|
|
'/^([\'"])\s*\S+script\s*:.*([\'"])/si',
|
|
'/^([\'"])\s*mocha\s*:*.*([\'"])/si',
|
|
'/^([\'"])\s*about\s*:.*([\'"])/si'
|
|
),
|
|
array(
|
|
"\\1$trans_image_path\\2",
|
|
"\\1$trans_image_path\\2",
|
|
"\\1$trans_image_path\\2"
|
|
)
|
|
),
|
|
"/^href|action/i" =>
|
|
array(
|
|
array(
|
|
'/^([\'"])\s*\S+script\s*:.*([\'"])/si',
|
|
'/^([\'"])\s*mocha\s*:*.*([\'"])/si',
|
|
'/^([\'"])\s*about\s*:.*([\'"])/si'
|
|
),
|
|
array(
|
|
"\\1#\\1",
|
|
"\\1#\\1",
|
|
"\\1#\\1"
|
|
)
|
|
),
|
|
"/^style/i" =>
|
|
array(
|
|
array(
|
|
"/\/\*.*\*\//",
|
|
"/expression/i",
|
|
"/binding/i",
|
|
"/behaviou*r/i",
|
|
"/include-source/i",
|
|
'/position\s*:/i',
|
|
'/(\\\\)?u(\\\\)?r(\\\\)?l(\\\\)?/i',
|
|
'/url\s*\(\s*([\'"])\s*\S+script\s*:.*([\'"])\s*\)/si',
|
|
'/url\s*\(\s*([\'"])\s*mocha\s*:.*([\'"])\s*\)/si',
|
|
'/url\s*\(\s*([\'"])\s*about\s*:.*([\'"])\s*\)/si',
|
|
'/(.*)\s*:\s*url\s*\(\s*([\'"]*)\s*\S+script\s*:.*([\'"]*)\s*\)/si'
|
|
),
|
|
array(
|
|
"",
|
|
"idiocy",
|
|
"idiocy",
|
|
"idiocy",
|
|
"idiocy",
|
|
"idiocy",
|
|
"url",
|
|
"url(\\1#\\1)",
|
|
"url(\\1#\\1)",
|
|
"url(\\1#\\1)",
|
|
"\\1:url(\\2#\\3)"
|
|
)
|
|
)
|
|
)
|
|
);
|
|
|
|
if ($block_external_images) {
|
|
array_push(
|
|
$bad_attvals{'/.*/'}{'/^src|background/i'}[0],
|
|
'/^([\'\"])\s*https*:.*([\'\"])/si'
|
|
);
|
|
array_push(
|
|
$bad_attvals{'/.*/'}{'/^src|background/i'}[1],
|
|
"\\1$trans_image_path\\1"
|
|
);
|
|
array_push(
|
|
$bad_attvals{'/.*/'}{'/^style/i'}[0],
|
|
'/url\(([\'\"])\s*https*:.*([\'\"])\)/si'
|
|
);
|
|
array_push(
|
|
$bad_attvals{'/.*/'}{'/^style/i'}[1],
|
|
"url(\\1$trans_image_path\\1)"
|
|
);
|
|
}
|
|
|
|
$add_attr_to_tag = array(
|
|
"/^a$/i" =>
|
|
array('target' => '"_blank"')
|
|
);
|
|
|
|
$trusted = tln_sanitize(
|
|
$body,
|
|
$tag_list,
|
|
$rm_tags_with_content,
|
|
$self_closing_tags,
|
|
$force_tag_closing,
|
|
$rm_attnames,
|
|
$bad_attvals,
|
|
$add_attr_to_tag,
|
|
$trans_image_path,
|
|
$block_external_images
|
|
);
|
|
return $trusted;
|
|
}
|