<?php /* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */ /** * SafeHTML Parser * * PHP versions 4 and 5 * * @category HTML * @package System.Security * @author Roman Ivanov <thingol@mail.ru> * @copyright 2004-2005 Roman Ivanov * @license http://www.debian.org/misc/bsd.license BSD License (3 Clause) * @version 1.3.7 * @link http://pixel-apes.com/safehtml/ */ /** * This package requires HTMLSax3 package */ Prado::using('System.3rdParty.SafeHtml.HTMLSax3'); /** * * SafeHTML Parser * * This parser strips down all potentially dangerous content within HTML: * <ul> * <li>opening tag without its closing tag</li> * <li>closing tag without its opening tag</li> * <li>any of these tags: "base", "basefont", "head", "html", "body", "applet", * "object", "iframe", "frame", "frameset", "script", "layer", "ilayer", "embed", * "bgsound", "link", "meta", "style", "title", "blink", "xml" etc.</li> * <li>any of these attributes: on*, data*, dynsrc</li> * <li>javascript:/vbscript:/about: etc. protocols</li> * <li>expression/behavior etc. in styles</li> * <li>any other active content</li> * </ul> * It also tries to convert code to XHTML valid, but htmltidy is far better * solution for this task. * * <b>Example:</b> * <pre> * $parser =& new SafeHTML(); * $result = $parser->parse($doc); * </pre> * * @category HTML * @package System.Security * @author Roman Ivanov <thingol@mail.ru> * @copyright 1997-2005 Roman Ivanov * @license http://www.debian.org/misc/bsd.license BSD License (3 Clause) * @version Release: @package_version@ * @link http://pear.php.net/package/SafeHTML */ class TSafeHtmlParser { /** * Storage for resulting HTML output * * @var string * @access private */ private $_xhtml = ''; /** * Array of counters for each tag * * @var array * @access private */ private $_counter = array(); /** * Stack of unclosed tags * * @var array * @access private */ private $_stack = array(); /** * Array of counters for tags that must be deleted with all content * * @var array * @access private */ private $_dcCounter = array(); /** * Stack of unclosed tags that must be deleted with all content * * @var array * @access private */ private $_dcStack = array(); /** * Stores level of list (ol/ul) nesting * * @var int * @access private */ private $_listScope = 0; /** * Stack of unclosed list tags * * @var array * @access private */ private $_liStack = array(); /** * Array of prepared regular expressions for protocols (schemas) matching * * @var array * @access private */ private $_protoRegexps = array(); /** * Array of prepared regular expressions for CSS matching * * @var array * @access private */ private $_cssRegexps = array(); /** * List of single tags ("<tag />") * * @var array * @access public */ public $singleTags = array('area', 'br', 'img', 'input', 'hr', 'wbr', ); /** * List of dangerous tags (such tags will be deleted) * * @var array * @access public */ public $deleteTags = array( 'applet', 'base', 'basefont', 'bgsound', 'blink', 'body', 'embed', 'frame', 'frameset', 'head', 'html', 'ilayer', 'iframe', 'layer', 'link', 'meta', 'object', 'style', 'title', 'script', ); /** * List of dangerous tags (such tags will be deleted, and all content * inside this tags will be also removed) * * @var array * @access public */ public $deleteTagsContent = array('script', 'style', 'title', 'xml', ); /** * Type of protocols filtering ('white' or 'black') * * @var string * @access public */ public $protocolFiltering = 'white'; /** * List of "dangerous" protocols (used for blacklist-filtering) * * @var array * @access public */ public $blackProtocols = array( 'about', 'chrome', 'data', 'disk', 'hcp', 'help', 'javascript', 'livescript', 'lynxcgi', 'lynxexec', 'ms-help', 'ms-its', 'mhtml', 'mocha', 'opera', 'res', 'resource', 'shell', 'vbscript', 'view-source', 'vnd.ms.radio', 'wysiwyg', ); /** * List of "safe" protocols (used for whitelist-filtering) * * @var array * @access public */ public $whiteProtocols = array( 'ed2k', 'file', 'ftp', 'gopher', 'http', 'https', 'irc', 'mailto', 'news', 'nntp', 'telnet', 'webcal', 'xmpp', 'callto', ); /** * List of attributes that can contain protocols * * @var array * @access public */ public $protocolAttributes = array( 'action', 'background', 'codebase', 'dynsrc', 'href', 'lowsrc', 'src', ); /** * List of dangerous CSS keywords * * Whole style="" attribute will be removed, if parser will find one of * these keywords * * @var array * @access public */ public $cssKeywords = array( 'absolute', 'behavior', 'behaviour', 'content', 'expression', 'fixed', 'include-source', 'moz-binding', ); /** * List of tags that can have no "closing tag" * * @var array * @access public * @deprecated XHTML does not allow such tags */ public $noClose = array(); /** * List of block-level tags that terminates paragraph * * Paragraph will be closed when this tags opened * * @var array * @access public */ public $closeParagraph = array( 'address', 'blockquote', 'center', 'dd', 'dir', 'div', 'dl', 'dt', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'hr', 'isindex', 'listing', 'marquee', 'menu', 'multicol', 'ol', 'p', 'plaintext', 'pre', 'table', 'ul', 'xmp', ); /** * List of table tags, all table tags outside a table will be removed * * @var array * @access public */ public $tableTags = array( 'caption', 'col', 'colgroup', 'tbody', 'td', 'tfoot', 'th', 'thead', 'tr', ); /** * List of list tags * * @var array * @access public */ public $listTags = array('dir', 'menu', 'ol', 'ul', 'dl', ); /** * List of dangerous attributes * * @var array * @access public */ public $attributes = array('dynsrc'); //public $attributes = array('dynsrc', 'id', 'name', ); //id and name are dangerous? /** * List of allowed "namespaced" attributes * * @var array * @access public */ public $attributesNS = array('xml:lang', ); /** * Constructs class * * @access public */ public function __construct() { //making regular expressions based on Proto & CSS arrays foreach ($this->blackProtocols as $proto) { $preg = "/[\s\x01-\x1F]*"; for ($i=0; $i<strlen($proto); $i++) { $preg .= $proto{$i} . "[\s\x01-\x1F]*"; } $preg .= ":/i"; $this->_protoRegexps[] = $preg; } foreach ($this->cssKeywords as $css) { $this->_cssRegexps[] = '/' . $css . '/i'; } return true; } /** * Handles the writing of attributes - called from $this->_openHandler() * * @param array $attrs array of attributes $name => $value * @return boolean * @access private */ private function _writeAttrs ($attrs) { if (is_array($attrs)) { foreach ($attrs as $name => $value) { $name = strtolower($name); if (strpos($name, 'on') === 0) { continue; } if (strpos($name, 'data') === 0) { continue; } if (in_array($name, $this->attributes)) { continue; } if (!preg_match("/^[a-z0-9]+$/i", $name)) { if (!in_array($name, $this->attributesNS)) { continue; } } if (($value === TRUE) || (is_null($value))) { $value = $name; } if ($name == 'style') { // removes insignificant backslahes $value = str_replace("\\", '', $value); // removes CSS comments while (1) { $_value = preg_replace("!/\*.*?\*/!s", '', $value); if ($_value == $value) break; $value = $_value; } // replace all & to & $value = str_replace('&', '&', $value); $value = str_replace('&', '&', $value); foreach ($this->_cssRegexps as $css) { if (preg_match($css, $value)) { continue 2; } } foreach ($this->_protoRegexps as $proto) { if (preg_match($proto, $value)) { continue 2; } } } $tempval = preg_replace('/&#(\d+);?/me', "chr('\\1')", $value); //"' $tempval = preg_replace('/&#x([0-9a-f]+);?/mei', "chr(hexdec('\\1'))", $tempval); if ((in_array($name, $this->protocolAttributes)) && (strpos($tempval, ':') !== false)) { if ($this->protocolFiltering == 'black') { foreach ($this->_protoRegexps as $proto) { if (preg_match($proto, $tempval)) continue 2; } } else { $_tempval = explode(':', $tempval); $proto = $_tempval[0]; if (!in_array($proto, $this->whiteProtocols)) { continue; } } } $value = str_replace("\"", """, $value); $this->_xhtml .= ' ' . $name . '="' . $value . '"'; } } return true; } /** * Opening tag handler - called from HTMLSax * * @param object $parser HTML Parser * @param string $name tag name * @param array $attrs tag attributes * @return boolean * @access private */ public function _openHandler(&$parser, $name, $attrs) { $name = strtolower($name); if (in_array($name, $this->deleteTagsContent)) { array_push($this->_dcStack, $name); $this->_dcCounter[$name] = isset($this->_dcCounter[$name]) ? $this->_dcCounter[$name]+1 : 1; } if (count($this->_dcStack) != 0) { return true; } if (in_array($name, $this->deleteTags)) { return true; } if (!preg_match("/^[a-z0-9]+$/i", $name)) { if (preg_match("!(?:\@|://)!i", $name)) { $this->_xhtml .= '<' . $name . '>'; } return true; } if (in_array($name, $this->singleTags)) { $this->_xhtml .= '<' . $name; $this->_writeAttrs($attrs); $this->_xhtml .= ' />'; return true; } // TABLES: cannot open table elements when we are not inside table if ((isset($this->_counter['table'])) && ($this->_counter['table'] <= 0) && (in_array($name, $this->tableTags))) { return true; } // PARAGRAPHS: close paragraph when closeParagraph tags opening if ((in_array($name, $this->closeParagraph)) && (in_array('p', $this->_stack))) { $this->_closeHandler($parser, 'p'); } // LISTS: we should close <li> if <li> of the same level opening if ($name == 'li' && count($this->_liStack) && $this->_listScope == $this->_liStack[count($this->_liStack)-1]) { $this->_closeHandler($parser, 'li'); } // LISTS: we want to know on what nesting level of lists we are if (in_array($name, $this->listTags)) { $this->_listScope++; } if ($name == 'li') { array_push($this->_liStack, $this->_listScope); } $this->_xhtml .= '<' . $name; $this->_writeAttrs($attrs); $this->_xhtml .= '>'; array_push($this->_stack,$name); $this->_counter[$name] = isset($this->_counter[$name]) ? $this->_counter[$name]+1 : 1; return true; } /** * Closing tag handler - called from HTMLSax * * @param object $parsers HTML parser * @param string $name tag name * @return boolean * @access private */ public function _closeHandler(&$parser, $name) { $name = strtolower($name); if (isset($this->_dcCounter[$name]) && ($this->_dcCounter[$name] > 0) && (in_array($name, $this->deleteTagsContent))) { while ($name != ($tag = array_pop($this->_dcStack))) { $this->_dcCounter[$tag]--; } $this->_dcCounter[$name]--; } if (count($this->_dcStack) != 0) { return true; } if ((isset($this->_counter[$name])) && ($this->_counter[$name] > 0)) { while ($name != ($tag = array_pop($this->_stack))) { $this->_closeTag($tag); } $this->_closeTag($name); } return true; } /** * Closes tag * * @param string $tag tag name * @return boolean * @access private */ public function _closeTag($tag) { if (!in_array($tag, $this->noClose)) { $this->_xhtml .= '</' . $tag . '>'; } $this->_counter[$tag]--; if (in_array($tag, $this->listTags)) { $this->_listScope--; } if ($tag == 'li') { array_pop($this->_liStack); } return true; } /** * Character data handler - called from HTMLSax * * @param object $parser HTML parser * @param string $data textual data * @return boolean * @access private */ public function _dataHandler(&$parser, $data) { if (count($this->_dcStack) == 0) { $this->_xhtml .= $data; } return true; } /** * Escape handler - called from HTMLSax * * @param object $parser HTML parser * @param string $data comments or other type of data * @return boolean * @access private */ public function _escapeHandler(&$parser, $data) { return true; } /** * Returns the XHTML document * * @return string Processed (X)HTML document * @access public */ public function getXHTML () { while ($tag = array_pop($this->_stack)) { $this->_closeTag($tag); } return $this->_xhtml; } /** * Clears current document data * * @return boolean * @access public */ public function clear() { $this->_xhtml = ''; return true; } /** * Main parsing fuction * * @param string $doc HTML document for processing * @return string Processed (X)HTML document * @access public */ public function parse($doc) { $this->clear(); // Save all '<' symbols $doc = preg_replace("/<(?=[^a-zA-Z\/\!\?\%])/", '<', (string)$doc); // Web documents shouldn't contains \x00 symbol $doc = str_replace("\x00", '', $doc); // Opera6 bug workaround $doc = str_replace("\xC0\xBC", '<', $doc); // UTF-7 encoding ASCII decode $doc = $this->repackUTF7($doc); // Instantiate the parser $parser= new TSax3(); // Set up the parser $parser->set_object($this); $parser->set_element_handler('_openHandler','_closeHandler'); $parser->set_data_handler('_dataHandler'); $parser->set_escape_handler('_escapeHandler'); $parser->parse($doc); return $this->getXHTML(); } /** * UTF-7 decoding fuction * * @param string $str HTML document for recode ASCII part of UTF-7 back to ASCII * @return string Decoded document * @access private */ private function repackUTF7($str) { return preg_replace_callback('!\+([0-9a-zA-Z/]+)\-!', array($this, 'repackUTF7Callback'), $str); } /** * Additional UTF-7 decoding fuction * * @param string $str String for recode ASCII part of UTF-7 back to ASCII * @return string Recoded string * @access private */ private function repackUTF7Callback($str) { $str = base64_decode($str[1]); $str = preg_replace_callback('/^((?:\x00.)*)((?:[^\x00].)+)/', array($this, 'repackUTF7Back'), $str); return preg_replace('/\x00(.)/', '$1', $str); } /** * Additional UTF-7 encoding fuction * * @param string $str String for recode ASCII part of UTF-7 back to ASCII * @return string Recoded string * @access private */ private function repackUTF7Back($str) { return $str[1].'+'.rtrim(base64_encode($str[2]), '=').'-'; } } /* * Local variables: * tab-width: 4 * c-basic-offset: 4 * c-hanging-comment-ender-p: nil * End: */ ?>