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<?php
use Dom\HTMLDocument;use Masterminds\HTML5;
/* +-----------------------------------------------------------------------+ | This file is part of the Roundcube Webmail client | | | | Copyright (C) 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 sanitizer (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 sanitizer.
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.*/
/** * Utility class providing HTML sanitizer */class rcube_washtml{ /** * @var array Allowed HTML elements (default) */ public static $html_elements = ['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', 'video', 'source', // form elements
'button', 'input', 'textarea', 'select', 'option', 'optgroup', // SVG
'svg', 'altglyph', 'altglyphdef', 'altglyphitem', 'animate', 'animatecolor', 'animatetransform', 'circle', 'clippath', 'defs', 'desc', 'ellipse', 'font', 'g', 'glyph', 'glyphref', 'hkern', 'image', 'line', 'lineargradient', 'marker', 'mask', 'mpath', 'path', 'pattern', 'polygon', 'polyline', 'radialgradient', 'rect', 'set', 'stop', 'switch', 'symbol', 'text', 'textpath', 'tref', 'tspan', 'use', 'view', 'vkern', 'filter', // SVG Filters
'feblend', 'fecolormatrix', 'fecomponenttransfer', 'fecomposite', 'feconvolvematrix', 'fediffuselighting', 'fedisplacementmap', 'feflood', 'fefunca', 'fefuncb', 'fefuncg', 'fefuncr', 'fegaussianblur', 'feimage', 'femerge', 'femergenode', 'femorphology', 'feoffset', 'fespecularlighting', 'fetile', 'feturbulence', // MathML
'math', 'menclose', 'merror', 'mfenced', 'mfrac', 'mglyph', 'mi', 'mlabeledtr', 'mmuliscripts', 'mn', 'mo', 'mover', 'mpadded', 'mphantom', 'mroot', 'mrow', 'ms', 'mspace', 'msqrt', 'mstyle', 'msub', 'msup', 'msubsup', 'mtable', 'mtd', 'mtext', 'mtr', 'munder', 'munderover', 'maligngroup', 'malignmark', 'mprescripts', 'semantics', 'annotation', 'annotation-xml', 'none', 'infinity', 'matrix', 'matrixrow', 'ci', 'cn', 'sep', 'apply', 'plus', 'minus', 'eq', 'power', 'times', 'divide', 'csymbol', 'root', 'bvar', 'lowlimit', 'uplimit', ];
/** * @var array Ignore these HTML tags and their content */ public static $ignore_elements = ['script', 'applet', 'embed', 'style'];
/** * @var array Allowed HTML attributes */ public static $html_attribs = ['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', 'background', 'src', 'poster', 'href', 'headers', 'start', 'reversed', // attributes of form elements
'type', 'rows', 'cols', 'disabled', 'readonly', 'checked', 'multiple', 'value', 'for', // SVG
'accent-height', 'accumulate', 'additive', 'alignment-baseline', 'alphabetic', 'ascent', 'attributename', 'attributetype', 'azimuth', 'basefrequency', 'baseprofile', 'baseline-shift', 'begin', 'bias', 'by', 'clip', 'clip-path', 'clip-rule', 'color', 'color-interpolation', 'color-interpolation-filters', 'color-profile', 'color-rendering', 'cx', 'cy', 'd', 'dx', 'dy', 'diffuseconstant', 'direction', 'display', 'divisor', 'dur', 'edgemode', 'elevation', 'end', 'fill', 'fill-opacity', 'fill-rule', 'filter', 'flood-color', 'flood-opacity', 'font-family', 'font-size', 'font-size-adjust', 'font-stretch', 'font-style', 'font-variant', 'font-weight', 'from', 'fx', 'fy', 'g1', 'g2', 'glyph-name', 'glyphref', 'gradientunits', 'gradienttransform', 'image-rendering', 'in', 'in2', 'k', 'k1', 'k2', 'k3', 'k4', 'kerning', 'keypoints', 'keysplines', 'keytimes', 'lengthadjust', 'letter-spacing', 'kernelmatrix', 'kernelunitlength', 'lighting-color', 'local', 'marker-end', 'marker-mid', 'marker-start', 'markerheight', 'markerunits', 'markerwidth', 'maskcontentunits', 'maskunits', 'max', 'mask', 'mode', 'min', 'numoctaves', 'offset', 'operator', 'opacity', 'order', 'orient', 'orientation', 'origin', 'overflow', 'paint-order', 'path', 'pathlength', 'patterncontentunits', 'patterntransform', 'patternunits', 'points', 'preservealpha', 'r', 'rx', 'ry', 'radius', 'refx', 'refy', 'repeatcount', 'repeatdur', 'restart', 'rotate', 'scale', 'seed', 'shape-rendering', 'show', 'specularconstant', 'specularexponent', 'spreadmethod', 'stddeviation', 'stitchtiles', 'stop-color', 'stop-opacity', 'stroke-dasharray', 'stroke-dashoffset', 'stroke-linecap', 'stroke-linejoin', 'stroke-miterlimit', 'stroke-opacity', 'stroke', 'stroke-width', 'surfacescale', 'targetx', 'targety', 'transform', 'text-anchor', 'text-decoration', 'text-rendering', 'textlength', 'to', 'u1', 'u2', 'unicode', 'values', 'viewbox', 'visibility', 'vert-adv-y', 'version', 'vert-origin-x', 'vert-origin-y', 'word-spacing', 'wrap', 'writing-mode', 'xchannelselector', 'ychannelselector', 'x', 'x1', 'x2', 'xmlns', 'y', 'y1', 'y2', 'z', 'zoomandpan', // MathML
'accent', 'accentunder', 'bevelled', 'close', 'columnalign', 'columnlines', 'columnspan', 'denomalign', 'depth', 'display', 'displaystyle', 'encoding', 'fence', 'frame', 'largeop', 'length', 'linethickness', 'lspace', 'lquote', 'mathbackground', 'mathcolor', 'mathsize', 'mathvariant', 'maxsize', 'minsize', 'movablelimits', 'notation', 'numalign', 'open', 'rowalign', 'rowlines', 'rowspacing', 'rowspan', 'rspace', 'rquote', 'scriptlevel', 'scriptminsize', 'scriptsizemultiplier', 'selection', 'separator', 'separators', 'stretchy', 'subscriptshift', 'supscriptshift', 'symmetric', 'voffset', 'fontsize', 'fontweight', 'fontstyle', 'fontfamily', 'groupalign', 'edge', 'side', ];
/** * @var array Elements which could be empty and be returned in short form (<tag />) */ public static $void_elements = ['area', 'base', 'br', 'col', 'command', 'embed', 'hr', 'img', 'input', 'keygen', 'link', 'meta', 'param', 'source', 'track', 'wbr', // MathML
'sep', 'infinity', 'in', 'plus', 'eq', 'power', 'times', 'divide', 'root', 'maligngroup', 'none', 'mprescripts', ];
/** * @var array Additional allowed attributes of body element */ public static $body_attribs = ['alink', 'background', 'bgcolor', 'link', 'text', 'vlink'];
/** @var bool State indicating existence of linked objects in HTML */ public $extlinks = false;
/** @var array Current settings */ private $config = [ 'add_comments' => true, 'allow_remote' => false, 'base_url' => '', 'charset' => RCUBE_CHARSET, 'cid_map' => [], 'show_washed' => true, ];
/** @var array Registered callback functions for tags */ private $handlers = [];
/** @var array Allowed HTML elements */ private $_html_elements = [];
/** @var array Ignore these HTML tags but process their content */ private $_ignore_elements = [];
/** @var array Elements which could be empty and be returned in short form (<tag />) */ private $_void_elements = [];
/** @var array Allowed HTML attributes */ private $_html_attribs = [];
/** @var string A prefix to be added to id/class/for attribute values */ private $_css_prefix;
/** @var int Max nesting level */ private $max_nesting_level;
/** @var bool Indicates that a nesting level error was logged */ private $max_nesting_level_error = false;
/** @var bool True if current document is XML */ private $is_xml = false;
/** * Class constructor * * @param array $p Configuration options: * allow_remote: is a boolean to allow link to remote resources (images/css) * blocked_src: string with image-src to be used for blocked remote images * show_washed: is a boolean to include washed out attributes as x-washed * cid_map: is an array where cid urls index urls to replace them * charset: is a string containing the charset of the HTML document, to be used if the charset is not defined in the document * css_prefix: A prefix to be added to id/class/for attribute values * html_elements: Additional allowed HTML elements * ignore_elements: Additional HTML elements to ignore * html_attribs: Additional allowed HTML attributes * void_elements: Elements which could be empty and be returned in short form (<tag />) */ public function __construct($p = []) { $p['html_elements'] = isset($p['html_elements']) ? (array) $p['html_elements'] : []; $p['html_attribs'] = isset($p['html_attribs']) ? (array) $p['html_attribs'] : []; $p['ignore_elements'] = isset($p['ignore_elements']) ? (array) $p['ignore_elements'] : []; $p['void_elements'] = isset($p['void_elements']) ? (array) $p['void_elements'] : [];
$this->_html_elements = array_flip($p['html_elements']) + array_flip(self::$html_elements); $this->_html_attribs = array_flip($p['html_attribs']) + array_flip(self::$html_attribs); $this->_ignore_elements = array_flip($p['ignore_elements']) + array_flip(self::$ignore_elements); $this->_void_elements = array_flip($p['void_elements']) + array_flip(self::$void_elements); $this->_css_prefix = isset($p['css_prefix']) && strlen($p['css_prefix']) ? $p['css_prefix'] : null;
unset($p['html_elements'], $p['html_attribs'], $p['ignore_elements'], $p['void_elements'], $p['css_prefix']);
$this->config = array_merge($this->config, $p); }
/** * Register a callback function for a certain tag * * @param string $tag HTML tag name * @param callable $callback Callback function
*/ public function add_callback($tag, $callback) { $this->handlers[$tag] = $callback; }
/** * Check CSS style * * @param string $style CSS style * * @return string Washed CSS style */ private function wash_style($style) { $result = [];
// Decode insecure character sequences
$style = rcube_utils::xss_entity_decode($style);
// Remove unwanted white-space characters
$style = preg_replace('/[\n\r\t]+/', ' ', $style);
$uri_callback = function ($uri) { if ($uri = $this->wash_uri($uri)) { return htmlspecialchars($uri, \ENT_QUOTES, $this->config['charset']); } };
return rtrim(rcube_utils::sanitize_css_block($style, $uri_callback), ';'); }
/** * Take a node and return allowed attributes and check values * * @param DOMElement $node Document element * * @return string Washed element attributes */ private function wash_attribs($node) { $result = ''; $washed = []; $additional_attribs = [];
if ($node->nodeName == 'body') { $additional_attribs = self::$body_attribs; }
foreach ($node->attributes as $name => $attr) { $key = strtolower($name); $value = $attr->nodeValue;
if ($key == 'style' && ($style = $this->wash_style($value))) { // replace double quotes to prevent syntax error and XSS issues (#1490227)
$result .= ' style="' . str_replace('"', '"', $style) . '"'; } elseif (isset($this->_html_attribs[$key]) || in_array($key, $additional_attribs)) { $value = trim($value); $out = null;
// in SVG to/from attribs may contain anything, including URIs
if ($key == 'to' || $key == 'from') { $key = strtolower((string) $node->getAttribute('attributeName')); if ($key && !isset($this->_html_attribs[$key])) { $key = null; } }
if ($this->is_image_attribute($node->nodeName, $key)) { $out = $this->wash_uri($value, true); } elseif ($this->is_link_attribute($node->nodeName, $key)) { $out = $this->wash_link($value); } elseif ($this->is_funciri_attribute($node->nodeName, $key)) { if (preg_match('/^[a-z:]*url\(/i', $value)) { if (preg_match('/^([a-z:]*url)\(\s*[\'"]?([^\'"\)]*)[\'"]?\s*\)/iu', $value, $match)) { if ($url = $this->wash_uri($match[2])) { $result .= ' ' . $attr->nodeName . '="' . $match[1] . '(' . htmlspecialchars($url, \ENT_QUOTES, $this->config['charset']) . ')' . htmlspecialchars(substr($value, strlen($match[0])), \ENT_QUOTES, $this->config['charset']) . '"'; continue; } } else { $out = $value; } } else { $out = $value; } } elseif ($this->_css_prefix !== null && (in_array($key, ['id', 'class', 'for']) || ($key == 'name' && $node->nodeName == 'a')) ) { $out = preg_replace('/(\S+)/', $this->_css_prefix . '\1', $value); } elseif ($key == 'xmlns' && !strpos($value, '://')) { continue; } elseif ($key) { $out = $value; }
if ($out !== null && $out !== '') { $v = htmlspecialchars($out, \ENT_QUOTES | \ENT_SUBSTITUTE, $this->config['charset']); $result .= " {$attr->nodeName}=\"{$v}\""; } elseif ($value) { $washed[] = htmlspecialchars($attr->nodeName, \ENT_QUOTES, $this->config['charset']); } } else { $washed[] = htmlspecialchars($attr->nodeName, \ENT_QUOTES, $this->config['charset']); } }
if (!empty($washed) && $this->config['show_washed']) { $result .= ' x-washed="' . implode(' ', $washed) . '"'; }
return $result; }
/** * Wash URI value * * @param string $uri URI * @param bool $blocked_source Block remote source * @param bool $is_image URI points to an image * * @return string Washed URI */ private function wash_uri($uri, $blocked_source = false, $is_image = true) { if (!empty($this->config['cid_map'][$uri])) { return $this->config['cid_map'][$uri]; }
$key = $this->config['base_url'] . $uri; if (!empty($this->config['cid_map'][$key])) { return $this->config['cid_map'][$key]; }
// allow url(#id) used in SVG
if (isset($uri[0]) && $uri[0] == '#') { if ($this->_css_prefix !== null) { $uri = '#' . $this->_css_prefix . substr($uri, 1); }
return $uri; }
if (preg_match('/^(http|https|ftp):.+/i', $uri)) { if (!empty($this->config['allow_remote'])) { return $uri; }
$this->extlinks = true; if ($is_image && !empty($this->config['blocked_src'])) { return $this->config['blocked_src']; } } elseif ($is_image && preg_match('/^data:image\/([^,]+),(.+)$/is', $uri, $matches)) { // RFC2397
$type = preg_replace('/\s/', '', $matches[1]);
// svg images can be insecure, we'll sanitize them
if (stripos($type, 'svg') !== false) { $svg = $matches[2];
if (stripos($type, ';base64') !== false) { $svg = base64_decode($svg); } else { $type .= ';base64'; }
$washer = new self($this->config); $svg = $washer->wash($svg);
// Invalid svg content
if (empty($svg)) { return ''; }
return 'data:image/' . $type . ',' . base64_encode($svg); }
return $uri; }
return ''; }
/** * Wash Href value * * @param string $href Href attribute value (link) * * @return string Washed href */ private function wash_link($href) { if (strlen($href) && !preg_match('!^(javascript|vbscript|data:)!i', $href)) { if ($href[0] == '#' && $this->_css_prefix !== null) { return '#' . $this->_css_prefix . substr($href, 1); }
if (preg_match('!^[a-zA-Z._-]+$!', $href)) { return 'http://' . $href; }
if (preg_match('!^([a-z][a-z0-9.+-]+:|//|#).+!i', $href)) { return $href; } }
return ''; }
/** * Check it the tag/attribute may contain an URI * * @param string $tag Element name * @param string $attr Attribute name * * @return bool True if attribute may contain an URI, False otherwise */ private function is_link_attribute($tag, $attr) { return $attr === 'href'; }
/** * Check it the tag/attribute may contain an image URI * * @param string $tag Element name * @param string $attr Attribute name * * @return bool True if attribute may contain an image URI, False otherwise */ private function is_image_attribute($tag, $attr) { return $attr == 'background' || $attr == 'color-profile' // SVG
|| ($attr == 'poster' && $tag == 'video') || ($attr == 'src' && preg_match('/^(img|image|source|input|video|audio)$/i', $tag)) || ($tag == 'use' && $attr == 'href') // SVG
|| ($tag == 'image' && $attr == 'href'); // SVG
}
/** * Check it the tag/attribute may contain a FUNCIRI value * * @param string $tag Element name * @param string $attr Attribute name * * @return bool True if attribute may contain a FUNCIRI value, False otherwise */ private function is_funciri_attribute($tag, $attr) { return in_array($attr, ['fill', 'filter', 'stroke', 'marker-start', 'marker-end', 'marker-mid', 'clip-path', 'mask', 'cursor']); }
/** * Check if a specified element has an attribute with specified value. * Do it in case-insensitive manner. * * @param DOMElement $node The element * @param string $attr_name The attribute name * @param string $attr_value The attribute value to find * * @return bool True if the specified attribute exists and has the expected value */ private static function attribute_value($node, $attr_name, $attr_value) { $attr_name = strtolower($attr_name);
foreach ($node->attributes as $name => $attr) { if (strtolower($name) === $attr_name) { if (strtolower($attr_value) === strtolower(trim($attr->nodeValue))) { return true; } } }
return false; }
/** * The main loop that recurse on a node tree. * It output only allowed tags with allowed attributes and allowed inline styles * * @param DOMNode $node HTML element * @param int $level Recurrence level (safe initial value found empirically) * * @return string HTML content */ private function dumpHtml($node, $level = 20) { if (!$node->hasChildNodes()) { return ''; }
$level++;
if ($this->max_nesting_level > 0 && $level == $this->max_nesting_level - 1) { // log error message once
if (empty($this->max_nesting_level_error)) { $this->max_nesting_level_error = true; rcube::raise_error([ 'code' => 500, 'message' => "Maximum nesting level exceeded (xdebug.max_nesting_level={$this->max_nesting_level})", ], true, false); }
return $this->config['add_comments'] ? '<!-- ignored -->' : ''; }
$node = $node->firstChild; $dump = '';
do { switch ($node->nodeType) { case \XML_ELEMENT_NODE: /** @var DOMElement $node */ $tagName = strtolower($node->nodeName);
if ($tagName == 'link') { $uri = $this->wash_uri($node->getAttribute('href'), false, false); if (!$uri) { if ($this->config['add_comments']) { $dump .= '<!-- link ignored -->'; } break; }
$node->setAttribute('href', (string) $uri); } elseif (in_array($tagName, ['animate', 'animatecolor', 'set', 'animatetransform']) && self::attribute_value($node, 'attributename', 'href') ) { // Insecure svg tags
if ($this->config['add_comments']) { $dump .= "<!-- {$tagName} blocked -->"; } break; }
if (!empty($this->handlers[$tagName])) { $callback = $this->handlers[$tagName]; $dump .= call_user_func($callback, $tagName, $this->wash_attribs($node), $this->dumpHtml($node, $level), $this); } elseif (isset($this->_html_elements[$tagName])) { $content = $this->dumpHtml($node, $level); $tag = '<' . $tagName;
if ($tagName == 'svg') { if (method_exists($node, 'getInScopeNamespaces')) { $ns_nodes = $node->getInScopeNamespaces(); } else { $xpath = new DOMXPath($node->ownerDocument); $ns_nodes = $xpath->query('namespace::*'); }
foreach ($ns_nodes as $ns) { if (isset($ns->nodeName) && isset($ns->nodeValue) && $ns->nodeName != 'xmlns:xml' && preg_match('/^[a-zA-Z:-]+$/', $ns->nodeName) && strpos($ns->nodeValue, '://') ) { $tag .= sprintf(' %s="%s"', $ns->nodeName, htmlspecialchars($ns->nodeValue, \ENT_QUOTES, $this->config['charset']) ); } } } elseif ($tagName == 'textarea' && strpos($content, '<') !== false) { $content = htmlspecialchars($content, \ENT_QUOTES | \ENT_SUBSTITUTE, $this->config['charset']); }
$tag .= $this->wash_attribs($node);
if (isset($this->_ignore_elements[$tagName])) { $dump .= $content; } elseif ($content === '' && ($this->is_xml || isset($this->_void_elements[$tagName]))) { $dump .= $tag . ' />'; } else { $dump .= $tag . '>' . $content . '</' . $tagName . '>'; } } elseif (isset($this->_ignore_elements[$tagName])) { if ($this->config['add_comments']) { $dump .= '<!-- ' . htmlspecialchars($tagName, \ENT_QUOTES, $this->config['charset']) . ' not allowed -->'; } } else { if ($this->config['add_comments']) { $dump .= '<!-- ' . htmlspecialchars($tagName, \ENT_QUOTES, $this->config['charset']) . ' ignored -->'; } $dump .= $this->dumpHtml($node, $level); // ignore tags not its content
}
break; case \XML_CDATA_SECTION_NODE: case \XML_TEXT_NODE: $dump .= htmlspecialchars($node->nodeValue, \ENT_COMPAT | \ENT_HTML401 | \ENT_SUBSTITUTE, $this->config['charset']); break; case \XML_HTML_DOCUMENT_NODE: $dump .= $this->dumpHtml($node, $level); break; } } while ($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. * * @param string $html HTML content * * @return string Washed HTML content */ public function wash($html) { $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'] = ''; }
// Detect max nesting level (for dumpHTML) (#1489110)
$this->max_nesting_level = (int) @ini_get('xdebug.max_nesting_level');
// SVG need to be parsed as XML
$this->is_xml = !preg_match('/<(html|head|body)/i', $html) && stripos($html, '<svg') !== false; $method = $this->is_xml ? 'loadXML' : 'loadHTML';
// Try HTML5 parser available in PHP >= 8.4
// TODO: Parse XML also with this new PHP parser (?)
if (!$this->is_xml && class_exists('Dom\HTMLDocument')) { try { $options = constant('Dom\HTML_NO_DEFAULT_NS') | \LIBXML_COMPACT | \LIBXML_NOERROR; $node = HTMLDocument::createFromString($html, $options, $this->config['charset']); } catch (Exception $e) { // ignore, fallback to other methods
} }
// DOMDocument does not support HTML5, try Masterminds parser if available
if (empty($node) && !$this->is_xml && class_exists('Masterminds\HTML5')) { try { // disabled_html_ns=true is a workaround for the performance issue
// https://github.com/Masterminds/html5-php/issues/181
$html5 = new HTML5(['disable_html_ns' => true]); $node = $html5->loadHTML($this->fix_html5($html)); } catch (Exception $e) { // ignore, fallback to DOMDocument
} }
if (empty($node)) { // Charset seems to be ignored (probably if defined in the HTML document)
$node = new DOMDocument('1.0', $this->config['charset']); @$node->{$method}($html, \LIBXML_PARSEHUGE | \LIBXML_COMPACT | \LIBXML_NONET); }
unset($html); // release some memory
return $this->dumpHtml($node); }
/** * Getter for config parameters * * @param string $prop Configuration parameter name * * @return mixed Configuration parameter value */ public function get_config($prop) { $config_props = ['html_elements', 'html_attribs', 'ignore_elements', 'void_elements', 'css_prefix'];
if (in_array($prop, $config_props)) { return $this->{"_{$prop}"}; }
return $this->config[$prop] ?? null; }
/** * Clean HTML input * * @param string $html HTML content * * @return string Clean HTML content */ private function cleanup($html) { $html = trim($html);
// special replacements (not properly handled by washtml class)
$html_search = [ // space(s) between <NOBR>
'/(<\/nobr>)(\s+)(<nobr>)/i', // PHP bug #32547 workaround: remove title tag
'/<title[^>]*>.*<\/title>/iU', // remove <!doctype> before BOM (#1490291)
'/<\!doctype[^>]+>[^<]*/im', // byte-order mark (only outlook?)
'/^(\0\0\xFE\xFF|\xFF\xFE\0\0|\xFE\xFF|\xFF\xFE|\xEF\xBB\xBF)/', // washtml/DOMDocument cannot handle xml namespaces
'/<html\s[^>]+>/i', // washtml/DOMDocument cannot handle xml namespaces
// HTML5 parser cannot handler <?xml
'/<\?xml[^>]*>/i', ];
$html_replace = [ '\1 \3', '', '', '', '<html>', '', ];
$html = preg_replace($html_search, $html_replace, $html);
$err = ['message' => 'Could not clean up HTML!']; if ($html === null && rcube_utils::preg_error($err)) { return ''; }
// Replace all of those weird MS Word quotes and other high characters
$badwordchars = [ "\xe2\x80\x98", // left single quote
"\xe2\x80\x99", // right single quote
"\xe2\x80\x9c", // left double quote
"\xe2\x80\x9d", // right double quote
"\xe2\x80\x94", // em dash
"\xe2\x80\xa6", // ellipses
];
$fixedwordchars = [ "'", "'", '"', '"', '—', '...', ];
$html = str_replace($badwordchars, $fixedwordchars, $html);
// FIXME: HTML comments handling could be better. The code below can break comments (#6464),
// we should probably do not modify content inside comments at all.
// fix (unknown/malformed) HTML tags before "wash"
$html = preg_replace_callback('/(<(?!\!)[\/]*)([^\s>]+)([^>]*)/', [$this, 'html_tag_callback'], $html);
// Remove invalid HTML comments (#1487759)
// Note: We don't want to remove valid comments, conditional comments
// and MSOutlook comments (<!-->)
$html = preg_replace('/<!--[a-zA-Z0-9]+>/', '', $html);
// fix broken nested lists
self::fix_broken_lists($html);
// turn relative into absolute urls
$html = self::resolve_base($html);
return $html; }
/** * Callback function for HTML tags fixing * * @param array $matches Matched elements (from preg_replace_callback()) * * @return string Replacement string */ public static function html_tag_callback($matches) { // It might be an ending of a comment, ignore (#6464)
if (substr($matches[3], -2) == '--') { $matches[0] = ''; return implode('', $matches); }
$tagname = $matches[2]; $tagname = preg_replace([ '/:.*$/', // Microsoft's Smart Tags <st1:xxxx>
'/[^a-z0-9_\[\]\!?-]/i', // forbidden characters
], '', $tagname);
// fix invalid closing tags - remove any attributes (#1489446)
if ($matches[1] == '</') { $matches[3] = ''; }
return $matches[1] . $tagname . $matches[3]; }
/** * Convert all relative URLs according to a <base> in HTML * * @param string $body HTML body * * @return string HTML body */ public static function resolve_base($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 $body; }
/** * Fix broken nested lists, they are not handled properly by DOMDocument (#1488768)
* * @param string &$html HTML content */ public static function fix_broken_lists(&$html) { // do two rounds, one for <ol>, one for <ul>
foreach (['ol', 'ul'] as $tag) { $pos = 0; while (($pos = stripos($html, '<' . $tag, $pos)) !== false) { $pos++;
// make sure this is an ol/ul tag
if (!in_array($html[$pos + 2], [' ', '>'])) { continue; }
$p = $pos; $in_li = false; $li_pos = 0;
while (($p = strpos($html, '<', $p)) !== false) { $tt = strtolower(substr($html, $p, 4));
// li open tag
if ($tt == '<li>' || $tt == '<li ') { $in_li = true; $p += 4; } // li close tag
elseif ($tt == '</li' && in_array($html[$p + 4], [' ', '>'])) { $li_pos = $p; $in_li = false; $p += 4; } // ul/ol closing tag
elseif ($tt == '</' . $tag && in_array($html[$p + 4], [' ', '>'])) { break; } // nested ol/ul element out of li
elseif (!$in_li && $li_pos && ($tt == '<ol>' || $tt == '<ol ' || $tt == '<ul>' || $tt == '<ul ')) { // find closing tag of this ul/ol element
$element = substr($tt, 1, 2); $cpos = $p; do { $tpos = stripos($html, '<' . $element, $cpos + 1); $cpos = stripos($html, '</' . $element, $cpos + 1); } while ($tpos !== false && $cpos !== false && $cpos > $tpos);
// not found, this is invalid HTML, skip it
if ($cpos === false) { break; }
// get element content
$end = strpos($html, '>', $cpos); $len = $end - $p + 1; $element = substr($html, $p, $len);
// move element to the end of the last li
$html = substr_replace($html, '', $p, $len); $html = substr_replace($html, $element, $li_pos, 0);
$p = $end; } else { $p++; } } } } }
/** * Cleanup and workarounds on input to Masterminds/HTML5 * * @param string $html HTML content * * @return string HTML content */ protected function fix_html5($html) { // There might be content before html/body tag, we'll move it to the body
// We'll wrap it by a div container, it's an invalid HTML anyway
$prefix = ''; if (strpos($html, '<')) { $pos = stripos($html, '<!DOCTYPE') ?: stripos($html, '<html') ?: stripos($html, '<body'); $prefix = '<div>' . substr($html, 0, $pos) . '</div>'; $html = substr($html, $pos); }
// HTML5 requires <head> or <body> (#6713)
// https://github.com/Masterminds/html5-php/issues/166
if ($prefix !== '' || !preg_match('/<(head|body)/i', $html)) { $body_pos = stripos($html, '<body'); $pos = $body_pos !== false ? $body_pos : stripos($html, '<html');
// No HTML and no BODY tag
if ($pos === false) { $html = '<html><body>' . $prefix . $html; } // Either HTML or BODY tag found
else { $pos = strpos($html, '>', $pos); $html = substr_replace($html, ($body_pos === false ? '<body>' : '') . $prefix, $pos + 1, 0); } }
// Workaround for HTML5 issue with "invalid" table structure (#7356)
$html = preg_replace('|<tr>\s*<tr>|', '<tr>', $html); $html = preg_replace('|</tr>\s*</tr>|', '</tr>', $html);
return $html; }}
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