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a40c1f9e83
There are many (I belive around 5%) Chinese character coded in GB2312 contains \xad, remove all \xad make the characters broken. Image you see one broken ideograph in every sentence:(
671 lines
21 KiB
PHP
671 lines
21 KiB
PHP
<?php
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/*
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* This is a fork of a slick piece of procedural code called 'kses' written by Ulf Harnhammar
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* The entire set of functions was wrapped in a PHP object with some internal modifications
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* by Richard Vasquez (http://www.chaos.org/) 7/25/2003
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*
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* The original (procedural) version of the code can be found at:
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* http://sourceforge.net/projects/kses/
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*
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* [kses strips evil scripts!]
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*
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* ==========================================================================================
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*
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* class.kses.php 0.0.2 - PHP class that filters HTML/XHTML only allowing some elements and
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* attributes to be passed through.
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*
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* Copyright (C) 2003 Richard R. Vasquez, Jr.
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*
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* Derived from kses 0.2.1 - HTML/XHTML filter that only allows some elements and attributes
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* Copyright (C) 2002, 2003 Ulf Harnhammar
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*
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* ==========================================================================================
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*
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* This program is free software and open source software; you can redistribute
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* it and/or modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the License,
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* or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA or visit
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* http://www.gnu.org/licenses/gpl.html
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*
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* ==========================================================================================
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* CONTACT INFORMATION:
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*
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* Email: View current valid email address at http://www.chaos.org/contact/
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*/
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class kses
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{
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var $allowed_protocols = array('http', 'https', 'ftp', 'news', 'nntp', 'telnet', 'gopher', 'mailto');
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var $allowed_html = array();
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function kses()
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{
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}
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function Parse($string = "")
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{
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if (get_magic_quotes_gpc())
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{
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$string = stripslashes($string);
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}
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$string = $this->_no_null($string);
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$string = $this->_js_entities($string);
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$string = $this->_normalize_entities($string);
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$string = $this->_hook($string);
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return $this->_split($string);
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}
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function Protocols()
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{
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$c_args = func_num_args();
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if($c_args != 1)
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{
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return false;
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}
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$protocol_data = func_get_arg(0);
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if(is_array($protocol_data))
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{
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foreach($protocol_data as $protocol)
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{
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$this->AddProtocol($protocol);
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}
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}
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elseif(is_string($protocol_data))
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{
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$this->AddProtocol($protocol_data);
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return true;
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}
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else
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{
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trigger_error("kses::Protocols() did not receive a string or an array.", E_USER_WARNING);
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return false;
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}
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}
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function AddProtocol($protocol = "")
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{
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if(!is_string($protocol))
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{
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trigger_error("kses::AddProtocol() requires a string.", E_USER_WARNING);
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return false;
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}
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$protocol = strtolower(trim($protocol));
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if($protocol == "")
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{
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trigger_error("kses::AddProtocol() tried to add an empty/NULL protocol.", E_USER_WARNING);
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return false;
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}
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// Remove any inadvertent ':' at the end of the protocol.
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if(substr($protocol, strlen($protocol) - 1, 1) == ":")
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{
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$protocol = substr($protocol, 0, strlen($protocol) - 1);
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}
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if(!in_array($protocol, $this->allowed_protocols))
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{
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array_push($this->allowed_protocols, $protocol);
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sort($this->allowed_protocols);
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}
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return true;
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}
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function AddHTML($tag = "", $attribs = array())
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{
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if(!is_string($tag))
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{
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trigger_error("kses::AddHTML() requires the tag to be a string", E_USER_WARNING);
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return false;
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}
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$tag = strtolower(trim($tag));
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if($tag == "")
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{
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trigger_error("kses::AddHTML() tried to add an empty/NULL tag", E_USER_WARNING);
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return false;
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}
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if(!is_array($attribs))
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{
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trigger_error("kses::AddHTML() requires an array (even an empty one) of attributes for '$tag'", E_USER_WARNING);
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return false;
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}
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$new_attribs = array();
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foreach($attribs as $idx1 => $val1)
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{
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$new_idx1 = strtolower($idx1);
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$new_val1 = $attribs[$idx1];
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if(is_array($new_val1))
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{
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$tmp_val = array();
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foreach($new_val1 as $idx2 => $val2)
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{
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$new_idx2 = strtolower($idx2);
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$tmp_val[$new_idx2] = $val2;
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}
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$new_val1 = $tmp_val;
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}
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$new_attribs[$new_idx1] = $new_val1;
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}
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$this->allowed_html[$tag] = $new_attribs;
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return true;
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}
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###############################################################################
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# This function removes any NULL or chr(173) characters in $string.
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###############################################################################
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function _no_null($string)
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{
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$string = preg_replace('/\0+/', '', $string);
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$string = preg_replace('/(\\\\0)+/', '', $string);
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# commented out, because it breaks chinese chars
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#$string = preg_replace('/\xad+/', '', $string); # deals with Opera "feature"
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return $string;
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} # function _no_null
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###############################################################################
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# This function removes the HTML JavaScript entities found in early versions of
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# Netscape 4.
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###############################################################################
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function _js_entities($string)
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{
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return preg_replace('%&\s*\{[^}]*(\}\s*;?|$)%', '', $string);
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} # function _js_entities
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###############################################################################
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# This function normalizes HTML entities. It will convert "AT&T" to the correct
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# "AT&T", ":" to ":", "&#XYZZY;" to "&#XYZZY;" and so on.
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###############################################################################
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function _normalize_entities($string)
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{
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# Disarm all entities by converting & to &
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$string = str_replace('&', '&', $string);
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# Change back the allowed entities in our entity white list
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$string = preg_replace('/&([A-Za-z][A-Za-z0-9]{0,19});/', '&\\1;', $string);
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$string = preg_replace('/&#0*([0-9]{1,5});/e', '\$this->_normalize_entities2("\\1")', $string);
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$string = preg_replace('/&#([Xx])0*(([0-9A-Fa-f]{2}){1,2});/', '&#\\1\\2;', $string);
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return $string;
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} # function _normalize_entities
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###############################################################################
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# This function helps _normalize_entities() to only accept 16 bit values
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# and nothing more for &#number; entities.
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###############################################################################
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function _normalize_entities2($i)
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{
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return (($i > 65535) ? "&#$i;" : "&#$i;");
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} # function _normalize_entities2
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###############################################################################
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# You add any kses hooks here.
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###############################################################################
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function _hook($string)
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{
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return $string;
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} # function _hook
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###############################################################################
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# This function goes through an array, and changes the keys to all lower case.
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###############################################################################
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function _array_lc($inarray)
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{
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$outarray = array();
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foreach ($inarray as $inkey => $inval)
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{
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$outkey = strtolower($inkey);
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$outarray[$outkey] = array();
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foreach ($inval as $inkey2 => $inval2)
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{
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$outkey2 = strtolower($inkey2);
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$outarray[$outkey][$outkey2] = $inval2;
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} # foreach $inval
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} # foreach $inarray
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return $outarray;
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} # function _array_lc
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###############################################################################
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# This function searches for HTML tags, no matter how malformed. It also
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# matches stray ">" characters.
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###############################################################################
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function _split($string)
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{
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return preg_replace(
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'%(<'. # EITHER: <
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'[^>]*'. # things that aren't >
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'(>|$)'. # > or end of string
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'|>)%e', # OR: just a >
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"\$this->_split2('\\1')",
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$string);
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} # function _split
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function _split2($string)
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###############################################################################
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# This function does a lot of work. It rejects some very malformed things
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# like <:::>. It returns an empty string, if the element isn't allowed (look
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# ma, no strip_tags()!). Otherwise it splits the tag into an element and an
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# attribute list.
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###############################################################################
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{
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$string = $this->_stripslashes($string);
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if (substr($string, 0, 1) != '<')
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{
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# It matched a ">" character
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return '>';
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}
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if (!preg_match('%^<\s*(/\s*)?([a-zA-Z0-9]+)([^>]*)>?$%', $string, $matches))
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{
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# It's seriously malformed
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return '';
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}
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$slash = trim($matches[1]);
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$elem = $matches[2];
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$attrlist = $matches[3];
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if (!is_array($this->allowed_html[strtolower($elem)]))
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{
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# They are using a not allowed HTML element
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return '';
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}
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return $this->_attr("$slash$elem", $attrlist);
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} # function _split2
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###############################################################################
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# This function removes all attributes, if none are allowed for this element.
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# If some are allowed it calls s_hair() to split them further, and then it
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# builds up new HTML code from the data that _hair() returns. It also
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# removes "<" and ">" characters, if there are any left. One more thing it
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# does is to check if the tag has a closing XHTML slash, and if it does,
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# it puts one in the returned code as well.
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###############################################################################
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function _attr($element, $attr)
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{
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# Is there a closing XHTML slash at the end of the attributes?
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$xhtml_slash = '';
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if (preg_match('%\s/\s*$%', $attr))
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{
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$xhtml_slash = ' /';
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}
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# Are any attributes allowed at all for this element?
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if (count($this->allowed_html[strtolower($element)]) == 0)
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{
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return "<$element$xhtml_slash>";
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}
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# Split it
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$attrarr = $this->_hair($attr);
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# Go through $attrarr, and save the allowed attributes for this element
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# in $attr2
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$attr2 = '';
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foreach ($attrarr as $arreach)
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{
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$current = $this->allowed_html[strtolower($element)][strtolower($arreach['name'])];
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if ($current == '')
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{
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# the attribute is not allowed
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continue;
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}
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if (!is_array($current))
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{
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# there are no checks
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$attr2 .= ' '.$arreach['whole'];
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}
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else
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{
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# there are some checks
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$ok = true;
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foreach ($current as $currkey => $currval)
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{
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if (!$this->_check_attr_val($arreach['value'], $arreach['vless'], $currkey, $currval))
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{
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$ok = false;
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break;
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}
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}
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if ($ok)
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{
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# it passed them
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$attr2 .= ' '.$arreach['whole'];
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}
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} # if !is_array($current)
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} # foreach
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# Remove any "<" or ">" characters
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$attr2 = preg_replace('/[<>]/', '', $attr2);
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return "<$element$attr2$xhtml_slash>";
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} # function _attr
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###############################################################################
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# This function does a lot of work. It parses an attribute list into an array
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# with attribute data, and tries to do the right thing even if it gets weird
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# input. It will add quotes around attribute values that don't have any quotes
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# or apostrophes around them, to make it easier to produce HTML code that will
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# conform to W3C's HTML specification. It will also remove bad URL protocols
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# from attribute values.
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###############################################################################
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function _hair($attr)
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{
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$attrarr = array();
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$mode = 0;
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$attrname = '';
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# Loop through the whole attribute list
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while (strlen($attr) != 0)
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{
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# Was the last operation successful?
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$working = 0;
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switch ($mode)
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{
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case 0: # attribute name, href for instance
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if (preg_match('/^([-a-zA-Z]+)/', $attr, $match))
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{
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$attrname = $match[1];
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$working = $mode = 1;
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$attr = preg_replace('/^[-a-zA-Z]+/', '', $attr);
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}
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break;
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case 1: # equals sign or valueless ("selected")
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if (preg_match('/^\s*=\s*/', $attr)) # equals sign
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{
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$working = 1;
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$mode = 2;
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$attr = preg_replace('/^\s*=\s*/', '', $attr);
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break;
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}
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if (preg_match('/^\s+/', $attr)) # valueless
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{
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$working = 1;
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$mode = 0;
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$attrarr[] = array(
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'name' => $attrname,
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'value' => '',
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'whole' => $attrname,
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'vless' => 'y'
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);
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$attr = preg_replace('/^\s+/', '', $attr);
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}
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break;
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case 2: # attribute value, a URL after href= for instance
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if (preg_match('/^"([^"]*)"(\s+|$)/', $attr, $match)) # "value"
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{
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$thisval = $this->_bad_protocol($match[1]);
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$attrarr[] = array(
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'name' => $attrname,
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'value' => $thisval,
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'whole' => "$attrname=\"$thisval\"",
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'vless' => 'n'
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);
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$working = 1;
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$mode = 0;
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$attr = preg_replace('/^"[^"]*"(\s+|$)/', '', $attr);
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break;
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}
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if (preg_match("/^'([^']*)'(\s+|$)/", $attr, $match)) # 'value'
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{
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$thisval = $this->_bad_protocol($match[1]);
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$attrarr[] = array(
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'name' => $attrname,
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'value' => $thisval,
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'whole' => "$attrname='$thisval'",
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'vless' => 'n'
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);
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$working = 1;
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$mode = 0;
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$attr = preg_replace("/^'[^']*'(\s+|$)/", '', $attr);
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break;
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}
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if (preg_match("%^([^\s\"']+)(\s+|$)%", $attr, $match)) # value
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{
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$thisval = $this->_bad_protocol($match[1]);
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$attrarr[] = array(
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'name' => $attrname,
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'value' => $thisval,
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'whole' => "$attrname=\"$thisval\"",
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'vless' => 'n'
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);
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# We add quotes to conform to W3C's HTML spec.
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$working = 1;
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$mode = 0;
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$attr = preg_replace("%^[^\s\"']+(\s+|$)%", '', $attr);
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}
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break;
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} # switch
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if ($working == 0) # not well formed, remove and try again
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{
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$attr = $this->_html_error($attr);
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$mode = 0;
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}
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} # while
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# special case, for when the attribute list ends with a valueless
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# attribute like "selected"
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if ($mode == 1)
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{
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$attrarr[] = array(
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'name' => $attrname,
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'value' => '',
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'whole' => $attrname,
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'vless' => 'y'
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);
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}
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return $attrarr;
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} # function _hair
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###############################################################################
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# This function removes all non-allowed protocols from the beginning of
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# $string. It ignores whitespace and the case of the letters, and it does
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# understand HTML entities. It does its work in a while loop, so it won't be
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# fooled by a string like "javascript:javascript:alert(57)".
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###############################################################################
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function _bad_protocol($string)
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{
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$string = $this->_no_null($string);
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$string2 = $string.'a';
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while ($string != $string2)
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{
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$string2 = $string;
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$string = $this->_bad_protocol_once($string);
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} # while
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return $string;
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} # function _bad_protocol
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###############################################################################
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# This function searches for URL protocols at the beginning of $string, while
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# handling whitespace and HTML entities.
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###############################################################################
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function _bad_protocol_once($string)
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{
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return preg_replace(
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'/^((&[^;]*;|[\sA-Za-z0-9])*)'.
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'(:|:|&#[Xx]3[Aa];)\s*/e',
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'\$this->_bad_protocol_once2("\\1")',
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$string
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);
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return $string;
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} # function _bad_protocol_once
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###############################################################################
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# This function processes URL protocols, checks to see if they're in the white-
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# list or not, and returns different data depending on the answer.
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###############################################################################
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function _bad_protocol_once2($string)
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{
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$string2 = $this->_decode_entities($string2);
|
|
$string2 = preg_replace('/\s/', '', $string);
|
|
$string2 = $this->_no_null($string2);
|
|
$string2 = strtolower($string2);
|
|
|
|
$allowed = false;
|
|
foreach ($this->allowed_protocols as $one_protocol)
|
|
{
|
|
if (strtolower($one_protocol) == $string2)
|
|
{
|
|
$allowed = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if ($allowed)
|
|
{
|
|
return "$string2:";
|
|
}
|
|
else
|
|
{
|
|
return '';
|
|
}
|
|
} # function _bad_protocol_once2
|
|
|
|
###############################################################################
|
|
# This function performs different checks for attribute values. The currently
|
|
# implemented checks are "maxlen", "minlen", "maxval", "minval" and "valueless"
|
|
# with even more checks to come soon.
|
|
###############################################################################
|
|
function _check_attr_val($value, $vless, $checkname, $checkvalue)
|
|
{
|
|
$ok = true;
|
|
|
|
switch (strtolower($checkname))
|
|
{
|
|
# The maxlen check makes sure that the attribute value has a length not
|
|
# greater than the given value. This can be used to avoid Buffer Overflows
|
|
# in WWW clients and various Internet servers.
|
|
case 'maxlen':
|
|
if (strlen($value) > $checkvalue)
|
|
{
|
|
$ok = false;
|
|
}
|
|
break;
|
|
|
|
# The minlen check makes sure that the attribute value has a length not
|
|
# smaller than the given value.
|
|
case 'minlen':
|
|
if (strlen($value) < $checkvalue)
|
|
{
|
|
$ok = false;
|
|
}
|
|
break;
|
|
|
|
# The maxval check does two things: it checks that the attribute value is
|
|
# an integer from 0 and up, without an excessive amount of zeroes or
|
|
# whitespace (to avoid Buffer Overflows). It also checks that the attribute
|
|
# value is not greater than the given value.
|
|
# This check can be used to avoid Denial of Service attacks.
|
|
case 'maxval':
|
|
if (!preg_match('/^\s{0,6}[0-9]{1,6}\s{0,6}$/', $value))
|
|
{
|
|
$ok = false;
|
|
}
|
|
if ($value > $checkvalue)
|
|
{
|
|
$ok = false;
|
|
}
|
|
break;
|
|
|
|
# The minval check checks that the attribute value is a positive integer,
|
|
# and that it is not smaller than the given value.
|
|
case 'minval':
|
|
if (!preg_match('/^\s{0,6}[0-9]{1,6}\s{0,6}$/', $value))
|
|
{
|
|
$ok = false;
|
|
}
|
|
if ($value < $checkvalue)
|
|
{
|
|
$ok = false;
|
|
}
|
|
break;
|
|
|
|
# The valueless check checks if the attribute has a value
|
|
# (like <a href="blah">) or not (<option selected>). If the given value
|
|
# is a "y" or a "Y", the attribute must not have a value.
|
|
# If the given value is an "n" or an "N", the attribute must have one.
|
|
case 'valueless':
|
|
if (strtolower($checkvalue) != $vless)
|
|
{
|
|
$ok = false;
|
|
}
|
|
break;
|
|
|
|
} # switch
|
|
|
|
return $ok;
|
|
} # function _check_attr_val
|
|
|
|
###############################################################################
|
|
# This function changes the character sequence \" to just "
|
|
# It leaves all other slashes alone. It's really weird, but the quoting from
|
|
# preg_replace(//e) seems to require this.
|
|
###############################################################################
|
|
function _stripslashes($string)
|
|
{
|
|
return preg_replace('%\\\\"%', '"', $string);
|
|
} # function _stripslashes
|
|
|
|
###############################################################################
|
|
# This function deals with parsing errors in _hair(). The general plan is
|
|
# to remove everything to and including some whitespace, but it deals with
|
|
# quotes and apostrophes as well.
|
|
###############################################################################
|
|
function _html_error($string)
|
|
{
|
|
return preg_replace('/^("[^"]*("|$)|\'[^\']*(\'|$)|\S)*\s*/', '', $string);
|
|
} # function _html_error
|
|
|
|
###############################################################################
|
|
# This function decodes numeric HTML entities (A and A). It doesn't
|
|
# do anything with other entities like ä, but we don't need them in the
|
|
# URL protocol white listing system anyway.
|
|
###############################################################################
|
|
function _decode_entities($string)
|
|
{
|
|
$string = preg_replace('/&#([0-9]+);/e', 'chr("\\1")', $string);
|
|
$string = preg_replace('/&#[Xx]([0-9A-Fa-f]+);/e', 'chr(hexdec("\\1"))', $string);
|
|
return $string;
|
|
} # function _decode_entities
|
|
|
|
###############################################################################
|
|
# This function returns kses' version number.
|
|
###############################################################################
|
|
function _version()
|
|
{
|
|
return '0.0.2 (OOP fork of kses 0.2.1)';
|
|
} # function _version
|
|
}
|
|
?>
|