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Diffstat (limited to 'program/lib/Roundcube/rcube_washtml.php')
| -rw-r--r-- | program/lib/Roundcube/rcube_washtml.php | 453 |
1 files changed, 453 insertions, 0 deletions
diff --git a/program/lib/Roundcube/rcube_washtml.php b/program/lib/Roundcube/rcube_washtml.php new file mode 100644 index 000000000..27dff9f48 --- /dev/null +++ b/program/lib/Roundcube/rcube_washtml.php @@ -0,0 +1,453 @@ +<?php + +/** + +-----------------------------------------------------------------------+ + | This file is part of the Roundcube Webmail client | + | Copyright (C) 2008-2012, The Roundcube Dev Team | + | | + | Licensed under the GNU General Public License version 3 or | + | any later version with exceptions for skins & plugins. | + | See the README file for a full license statement. | + | | + | PURPOSE: | + | Utility class providing HTML sanityzer (based on Washtml class) | + +-----------------------------------------------------------------------+ + | Author: Thomas Bruederli <roundcube@gmail.com> | + | Author: Aleksander Machniak <alec@alec.pl> | + | Author: Frederic Motte <fmotte@ubixis.com> | + +-----------------------------------------------------------------------+ + */ + +/** + * Washtml, a HTML sanityzer. + * + * Copyright (c) 2007 Frederic Motte <fmotte@ubixis.com> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * OVERVIEW: + * + * Wahstml take an untrusted HTML and return a safe html string. + * + * SYNOPSIS: + * + * $washer = new washtml($config); + * $washer->wash($html); + * It return a sanityzed string of the $html parameter without html and head tags. + * $html is a string containing the html code to wash. + * $config is an array containing options: + * $config['allow_remote'] is a boolean to allow link to remote images. + * $config['blocked_src'] string with image-src to be used for blocked remote images + * $config['show_washed'] is a boolean to include washed out attributes as x-washed + * $config['cid_map'] is an array where cid urls index urls to replace them. + * $config['charset'] is a string containing the charset of the HTML document if it is not defined in it. + * $washer->extlinks is a reference to a boolean that is set to true if remote images were removed. (FE: show remote images link) + * + * INTERNALS: + * + * Only tags and attributes in the static lists $html_elements and $html_attributes + * are kept, inline styles are also filtered: all style identifiers matching + * /[a-z\-]/i are allowed. Values matching colors, sizes, /[a-z\-]/i and safe + * urls if allowed and cid urls if mapped are kept. + * + * Roundcube Changes: + * - added $block_elements + * - changed $ignore_elements behaviour + * - added RFC2397 support + * - base URL support + * - invalid HTML comments removal before parsing + * - "fixing" unitless CSS values for XHTML output + * - base url resolving + */ + +/** + * Utility class providing HTML sanityzer + * + * @package Framework + * @subpackage Utils + */ +class rcube_washtml +{ + /* Allowed HTML elements (default) */ + static $html_elements = array('a', 'abbr', 'acronym', 'address', 'area', 'b', + 'basefont', 'bdo', 'big', 'blockquote', 'br', 'caption', 'center', + 'cite', 'code', 'col', 'colgroup', 'dd', 'del', 'dfn', 'dir', 'div', 'dl', + 'dt', 'em', 'fieldset', 'font', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'hr', 'i', + 'ins', 'label', 'legend', 'li', 'map', 'menu', 'nobr', 'ol', 'p', 'pre', 'q', + 's', 'samp', 'small', 'span', 'strike', 'strong', 'sub', 'sup', 'table', + 'tbody', 'td', 'tfoot', 'th', 'thead', 'tr', 'tt', 'u', 'ul', 'var', 'wbr', 'img', + // form elements + 'button', 'input', 'textarea', 'select', 'option', 'optgroup' + ); + + /* Ignore these HTML tags and their content */ + static $ignore_elements = array('script', 'applet', 'embed', 'object', 'style'); + + /* Allowed HTML attributes */ + static $html_attribs = array('name', 'class', 'title', 'alt', 'width', 'height', + 'align', 'nowrap', 'col', 'row', 'id', 'rowspan', 'colspan', 'cellspacing', + 'cellpadding', 'valign', 'bgcolor', 'color', 'border', 'bordercolorlight', + 'bordercolordark', 'face', 'marginwidth', 'marginheight', 'axis', 'border', + 'abbr', 'char', 'charoff', 'clear', 'compact', 'coords', 'vspace', 'hspace', + 'cellborder', 'size', 'lang', 'dir', 'usemap', 'shape', 'media', + // attributes of form elements + 'type', 'rows', 'cols', 'disabled', 'readonly', 'checked', 'multiple', 'value' + ); + + /* Block elements which could be empty but cannot be returned in short form (<tag />) */ + static $block_elements = array('div', 'p', 'pre', 'blockquote', 'a', 'font', 'center', + 'table', 'ul', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'ol', 'dl', 'strong', + 'i', 'b', 'u', 'span', + ); + + /* State for linked objects in HTML */ + public $extlinks = false; + + /* Current settings */ + private $config = array(); + + /* Registered callback functions for tags */ + private $handlers = array(); + + /* Allowed HTML elements */ + private $_html_elements = array(); + + /* Ignore these HTML tags but process their content */ + private $_ignore_elements = array(); + + /* Block elements which could be empty but cannot be returned in short form (<tag />) */ + private $_block_elements = array(); + + /* Allowed HTML attributes */ + private $_html_attribs = array(); + + + /** + * Class constructor + */ + public function __construct($p = array()) + { + $this->_html_elements = array_flip((array)$p['html_elements']) + array_flip(self::$html_elements) ; + $this->_html_attribs = array_flip((array)$p['html_attribs']) + array_flip(self::$html_attribs); + $this->_ignore_elements = array_flip((array)$p['ignore_elements']) + array_flip(self::$ignore_elements); + $this->_block_elements = array_flip((array)$p['block_elements']) + array_flip(self::$block_elements); + + unset($p['html_elements'], $p['html_attribs'], $p['ignore_elements'], $p['block_elements']); + + $this->config = $p + array('show_washed' => true, 'allow_remote' => false, 'cid_map' => array()); + } + + /** + * Register a callback function for a certain tag + */ + public function add_callback($tagName, $callback) + { + $this->handlers[$tagName] = $callback; + } + + /** + * Check CSS style + */ + private function wash_style($style) + { + $s = ''; + + foreach (explode(';', $style) as $declaration) { + if (preg_match('/^\s*([a-z\-]+)\s*:\s*(.*)\s*$/i', $declaration, $match)) { + $cssid = $match[1]; + $str = $match[2]; + $value = ''; + + while (sizeof($str) > 0 && + preg_match('/^(url\(\s*[\'"]?([^\'"\)]*)[\'"]?\s*\)'./*1,2*/ + '|rgb\(\s*[0-9]+\s*,\s*[0-9]+\s*,\s*[0-9]+\s*\)'. + '|-?[0-9.]+\s*(em|ex|px|cm|mm|in|pt|pc|deg|rad|grad|ms|s|hz|khz|%)?'. + '|#[0-9a-f]{3,6}'. + '|[a-z0-9", -]+'. + ')\s*/i', $str, $match) + ) { + if ($match[2]) { + if (($src = $this->config['cid_map'][$match[2]]) + || ($src = $this->config['cid_map'][$this->config['base_url'].$match[2]]) + ) { + $value .= ' url('.htmlspecialchars($src, ENT_QUOTES) . ')'; + } + else if (preg_match('!^(https?:)?//[a-z0-9/._+-]+$!i', $match[2], $url)) { + if ($this->config['allow_remote']) { + $value .= ' url('.htmlspecialchars($url[0], ENT_QUOTES).')'; + } + else { + $this->extlinks = true; + } + } + else if (preg_match('/^data:.+/i', $match[2])) { // RFC2397 + $value .= ' url('.htmlspecialchars($match[2], ENT_QUOTES).')'; + } + } + else { + // whitelist ? + $value .= ' ' . $match[0]; + + // #1488535: Fix size units, so width:800 would be changed to width:800px + if (preg_match('/(left|right|top|bottom|width|height)/i', $cssid) + && preg_match('/^[0-9]+$/', $match[0]) + ) { + $value .= 'px'; + } + } + + $str = substr($str, strlen($match[0])); + } + + if (isset($value[0])) { + $s .= ($s?' ':'') . $cssid . ':' . $value . ';'; + } + } + } + + return $s; + } + + /** + * Take a node and return allowed attributes and check values + */ + private function wash_attribs($node) + { + $t = ''; + $washed = ''; + + foreach ($node->attributes as $key => $plop) { + $key = strtolower($key); + $value = $node->getAttribute($key); + + if (isset($this->_html_attribs[$key]) || + ($key == 'href' && ($value = trim($value)) + && !preg_match('!^(javascript|vbscript|data:text)!i', $value) + && preg_match('!^([a-z][a-z0-9.+-]+:|//|#).+!i', $value)) + ) { + $t .= ' ' . $key . '="' . htmlspecialchars($value, ENT_QUOTES) . '"'; + } + else if ($key == 'style' && ($style = $this->wash_style($value))) { + $quot = strpos($style, '"') !== false ? "'" : '"'; + $t .= ' style=' . $quot . $style . $quot; + } + else if ($key == 'background' || ($key == 'src' && strtolower($node->tagName) == 'img')) { //check tagName anyway + if (($src = $this->config['cid_map'][$value]) + || ($src = $this->config['cid_map'][$this->config['base_url'].$value]) + ) { + $t .= ' ' . $key . '="' . htmlspecialchars($src, ENT_QUOTES) . '"'; + } + else if (preg_match('/^(http|https|ftp):.+/i', $value)) { + if ($this->config['allow_remote']) { + $t .= ' ' . $key . '="' . htmlspecialchars($value, ENT_QUOTES) . '"'; + } + else { + $this->extlinks = true; + if ($this->config['blocked_src']) { + $t .= ' ' . $key . '="' . htmlspecialchars($this->config['blocked_src'], ENT_QUOTES) . '"'; + } + } + } + else if (preg_match('/^data:.+/i', $value)) { // RFC2397 + $t .= ' ' . $key . '="' . htmlspecialchars($value, ENT_QUOTES) . '"'; + } + } + else { + $washed .= ($washed ? ' ' : '') . $key; + } + } + + return $t . ($washed && $this->config['show_washed'] ? ' x-washed="'.$washed.'"' : ''); + } + + /** + * The main loop that recurse on a node tree. + * It output only allowed tags with allowed attributes + * and allowed inline styles + */ + private function dumpHtml($node) + { + if (!$node->hasChildNodes()) { + return ''; + } + + $node = $node->firstChild; + $dump = ''; + + do { + switch($node->nodeType) { + case XML_ELEMENT_NODE: //Check element + $tagName = strtolower($node->tagName); + if ($callback = $this->handlers[$tagName]) { + $dump .= call_user_func($callback, $tagName, + $this->wash_attribs($node), $this->dumpHtml($node), $this); + } + else if (isset($this->_html_elements[$tagName])) { + $content = $this->dumpHtml($node); + $dump .= '<' . $tagName . $this->wash_attribs($node) . + ($content != '' || isset($this->_block_elements[$tagName]) ? ">$content</$tagName>" : ' />'); + } + else if (isset($this->_ignore_elements[$tagName])) { + $dump .= '<!-- ' . htmlspecialchars($tagName, ENT_QUOTES) . ' not allowed -->'; + } + else { + $dump .= '<!-- ' . htmlspecialchars($tagName, ENT_QUOTES) . ' ignored -->'; + $dump .= $this->dumpHtml($node); // ignore tags not its content + } + break; + + case XML_CDATA_SECTION_NODE: + $dump .= $node->nodeValue; + break; + + case XML_TEXT_NODE: + $dump .= htmlspecialchars($node->nodeValue); + break; + + case XML_HTML_DOCUMENT_NODE: + $dump .= $this->dumpHtml($node); + break; + + case XML_DOCUMENT_TYPE_NODE: + break; + + default: + $dump . '<!-- node type ' . $node->nodeType . ' -->'; + } + } while($node = $node->nextSibling); + + return $dump; + } + + /** + * Main function, give it untrusted HTML, tell it if you allow loading + * remote images and give it a map to convert "cid:" urls. + */ + public function wash($html) + { + // Charset seems to be ignored (probably if defined in the HTML document) + $node = new DOMDocument('1.0', $this->config['charset']); + $this->extlinks = false; + + $html = $this->cleanup($html); + + // Find base URL for images + if (preg_match('/<base\s+href=[\'"]*([^\'"]+)/is', $html, $matches)) { + $this->config['base_url'] = $matches[1]; + } + else { + $this->config['base_url'] = ''; + } + + @$node->loadHTML($html); + return $this->dumpHtml($node); + } + + /** + * Getter for config parameters + */ + public function get_config($prop) + { + return $this->config[$prop]; + } + + /** + * Clean HTML input + */ + private function cleanup($html) + { + // special replacements (not properly handled by washtml class) + $html_search = array( + '/(<\/nobr>)(\s+)(<nobr>)/i', // space(s) between <NOBR> + '/<title[^>]*>[^<]*<\/title>/i', // PHP bug #32547 workaround: remove title tag + '/^(\0\0\xFE\xFF|\xFF\xFE\0\0|\xFE\xFF|\xFF\xFE|\xEF\xBB\xBF)/', // byte-order mark (only outlook?) + '/<html\s[^>]+>/i', // washtml/DOMDocument cannot handle xml namespaces + ); + + $html_replace = array( + '\\1'.' '.'\\3', + '', + '', + '<html>', + ); + $html = preg_replace($html_search, $html_replace, trim($html)); + + // PCRE errors handling (#1486856), should we use something like for every preg_* use? + if ($html === null && ($preg_error = preg_last_error()) != PREG_NO_ERROR) { + $errstr = "Could not clean up HTML message! PCRE Error: $preg_error."; + + if ($preg_error == PREG_BACKTRACK_LIMIT_ERROR) { + $errstr .= " Consider raising pcre.backtrack_limit!"; + } + if ($preg_error == PREG_RECURSION_LIMIT_ERROR) { + $errstr .= " Consider raising pcre.recursion_limit!"; + } + + rcube::raise_error(array('code' => 620, 'type' => 'php', + 'line' => __LINE__, 'file' => __FILE__, + 'message' => $errstr), true, false); + return ''; + } + + // fix (unknown/malformed) HTML tags before "wash" + $html = preg_replace_callback('/(<[\/]*)([^\s>]+)/', array($this, 'html_tag_callback'), $html); + + // Remove invalid HTML comments (#1487759) + // Don't remove valid conditional comments + // Don't remove MSOutlook (<!-->) conditional comments (#1489004) + $html = preg_replace('/<!--[^->\[\n]+>/', '', $html); + + // turn relative into absolute urls + $html = self::resolve_base($html); + + return $html; + } + + /** + * Callback function for HTML tags fixing + */ + public static function html_tag_callback($matches) + { + $tagname = $matches[2]; + $tagname = preg_replace(array( + '/:.*$/', // Microsoft's Smart Tags <st1:xxxx> + '/[^a-z0-9_\[\]\!-]/i', // forbidden characters + ), '', $tagname); + + return $matches[1] . $tagname; + } + + /** + * Convert all relative URLs according to a <base> in HTML + */ + public static function resolve_base($body) + { + // check for <base href=...> + if (preg_match('!(<base.*href=["\']?)([hftps]{3,5}://[a-z0-9/.%-]+)!i', $body, $regs)) { + $replacer = new rcube_base_replacer($regs[2]); + $body = $replacer->replace($body); + } + + return $body; + } +} + |