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Improve HTML sanitization with washtml

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release-0.6
thomascube 16 years ago
parent 808fb26b61
commit 21e724153e
4 changed files with 128 additions and 51 deletions
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1
program/include/rcube_message.php
Unescape Escape View File

@ -57,7 +57,6 @@ class rcube_message
list(, $this->sender) = each($this->imap->decode_address_list($this->headers->from));
$this->set_safe((intval($_GET['_safe']) || $_SESSION['safe_messages'][$uid]));
$this->set_safe(0);
$this->opt = array(
'safe' => $this->is_safe,

108
program/lib/washtml.php
Unescape Escape View File

@ -33,7 +33,8 @@
*
* SYNOPSIS:
*
* washtml::wash($html, $config, $full);
* $washer = new washtml($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:
@ -42,11 +43,11 @@
* $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.
* $full is a reference to a boolean that is set to true if no remote images are removed. (FE: show remote images link)
* $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 globals $html_elements and $html_attributes
* 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.
@ -72,15 +73,51 @@
class 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', 'ol', 'p', 'pre', 'q', 's', 'samp', 'small', 'span', 'strike', 'strong', 'sub', 'sup', 'table', 'tbody', 'td', 'tfoot', 'th', 'thead', 'tr', 'tt', 'u', 'ul', 'var', 'img');
/* Ignore these HTML tags but process their content */
static $ignore_elements = array('html', 'body');
/* 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', 'background');
/* 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 */
static $html_elements = array('a', 'abbr', 'acronym', 'address', 'area', 'b', 'basefont', 'bdo', 'big', 'blockquote', 'body', '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', 'ol', 'p', 'pre', 'q', 's', 'samp', 'small', 'span', 'strike', 'strong', 'sub', 'sup', 'table', 'tbody', 'td', 'tfoot', 'th', 'thead', 'title', 'tr', 'tt', 'u', 'ul', 'var', 'img');
private $_html_elements = array();
/* 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', 'background');
/* Ignore these HTML tags but process their content */
private $_ignore_elements = array();
/* Allowed HTML attributes */
private $_html_attribs = array();
/* Constructor */
public function __construct($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::$ignore_elements);
unset($p['html_elements'], $p['html_attribs'], $p['ignore_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] = $callback;
}
/* Check CSS style */
static function wash_style($style, $config, &$full) {
private function wash_style($style) {
$s = '';
foreach(explode(';', $style) as $declaration) {
@ -96,12 +133,12 @@ class washtml
')\s*/i', $str, $match)) {
if($match[2]) {
if(preg_match('/^(http|https|ftp):.*$/i', $match[2], $url)) {
if($config['allow_remote'])
if($this->config['allow_remote'])
$value .= ' url(\''.htmlspecialchars($url[0], ENT_QUOTES).'\')';
else
$full = false;
$this->extlinks = true;
} else if(preg_match('/^cid:(.*)$/i', $match[2], $cid))
$value .= ' url(\''.htmlspecialchars($config['cid_map']['cid:'.$cid[1]], ENT_QUOTES) . '\')';
$value .= ' url(\''.htmlspecialchars($this->config['cid_map']['cid:'.$cid[1]], ENT_QUOTES) . '\')';
} else if($match[0] != 'url' && $match[0] != 'rbg')//whitelist ?
$value .= ' ' . $match[0];
$str = substr($str, strlen($match[0]));
@ -114,39 +151,39 @@ class washtml
}
/* Take a node and return allowed attributes and check values */
static function wash_attribs($node, $config, &$full) {
private function wash_attribs($node) {
$t = '';
$washed;
foreach($node->attributes as $key => $plop) {
$key = strtolower($key);
$value = $node->getAttribute($key);
if((in_array($key, self::$html_attribs)) ||
if(isset($this->_html_attribs[$key]) ||
($key == 'href' && preg_match('/^(http|https|ftp|mailto):.*/i', $value)))
$t .= ' ' . $key . '="' . htmlspecialchars($value, ENT_QUOTES) . '"';
else if($key == 'style' && ($style = self::wash_style($value, $config, $full)))
else if($key == 'style' && ($style = $this->wash_style($value)))
$t .= ' style="' . $style . '"';
else if($key == 'src' && strtolower($node->tagName) == 'img') { //check tagName anyway
if(preg_match('/^(http|https|ftp):.*/i', $value)) {
if($config['allow_remote'])
if($this->config['allow_remote'])
$t .= ' ' . $key . '="' . htmlspecialchars($value, ENT_QUOTES) . '"';
else {
$full = false;
if ($config['blocked_src'])
$t .= ' src="' . htmlspecialchars($config['blocked_src'], ENT_QUOTES) . '"';
$this->extlinks = true;
if ($this->config['blocked_src'])
$t .= ' src="' . htmlspecialchars($this->config['blocked_src'], ENT_QUOTES) . '"';
}
} else if(preg_match('/^cid:(.*)$/i', $value, $cid))
$t .= ' ' . $key . '="' . htmlspecialchars($config['cid_map']['cid:'.$cid[1]], ENT_QUOTES) . '"';
$t .= ' ' . $key . '="' . htmlspecialchars($this->config['cid_map']['cid:'.$cid[1]], ENT_QUOTES) . '"';
} else
$washed .= ($washed?' ':'') . $key;
}
return $t . ($washed && $config['show_washed']?' x-washed="'.$washed.'"':'');
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 */
static function dumpHtml($node, $config, &$full) {
private function dumpHtml($node) {
if(!$node->hasChildNodes())
return '';
@ -157,23 +194,31 @@ class washtml
switch($node->nodeType) {
case XML_ELEMENT_NODE: //Check element
$tagName = strtolower($node->tagName);
if(in_array($tagName, self::$html_elements)) {
$content = self::dumpHtml($node, $config, $full);
$dump .= '<' . $tagName . self::wash_attribs($node, $config, $full) .
if($callback = $this->handlers[$tagName]) {
$dump .= call_user_func($callback, $tagName, $this->wash_attribs($node), $this->dumpHtml($node));
} else if(isset($this->_html_elements[$tagName])) {
$content = $this->dumpHtml($node);
$dump .= '<' . $tagName . $this->wash_attribs($node) .
($content?">$content</$tagName>":' />');
} else if($tagName == 'html' || $tagName == 'body') {
$dump .= self::dumpHtml($node, $config, $full); //Just ignored
} else if(isset($this->_ignore_elements[$tagName])) {
$dump .= '<!-- ' . htmlspecialchars($tagName, ENT_QUOTES) . ' ignored -->';
$dump .= $this->dumpHtml($node); //Just ignored
} else
$dump .= '<!-- ' . htmlspecialchars($tagName, ENT_QUOTES) . ' not allowed -->';
break;
case XML_CDATA_SECTION_NODE:
$dump .= $node->nodeValue;
break;
case XML_TEXT_NODE:
$dump .= htmlspecialchars($node->nodeValue);
break;
case XML_HTML_DOCUMENT_NODE:
$dump .= self::dumpHtml($node, $config, $full);
$dump .= $this->dumpHtml($node);
break;
case XML_DOCUMENT_TYPE_NODE:
break;
case XML_DOCUMENT_TYPE_NODE: break;
default:
$dump . '<!-- node type ' . $node->nodeType . ' -->';
}
} while($node = $node->nextSibling);
@ -182,13 +227,12 @@ class washtml
/* Main function, give it untrusted HTML, tell it if you allow loading
* remote images and give it a map to convert "cid:" urls. */
static function wash($html, $config=array(), &$full=true) {
$config += array('show_washed'=>true, 'allow_remote'=>false, 'cid_map'=>array());
public function wash($html) {
//Charset seems to be ignored (probably if defined in the HTML document)
$node = new DOMDocument('1.0', $config['charset']);
$full = true;
$node = new DOMDocument('1.0', $this->config['charset']);
$this->extlinks = false;
@$node->loadHTML($html);
return self::dumpHtml($node, $config, $full);
return $this->dumpHtml($node);
}
}

66
program/steps/mail/func.inc
Unescape Escape View File

@ -539,12 +539,14 @@ function rcmail_get_messagecount_text($count=NULL, $page=NULL)
* @param bool True if part should be converted to plaintext
* @return string Formatted HTML string
*/
function rcmail_print_body($part, $safe=false, $plain=false)
function rcmail_print_body($part, $p = array())
{
global $REMOTE_OBJECTS;
$p += array('safe' => false, 'plain' => false, 'inline_html' => true);
// convert html to text/plain
if ($part->ctype_secondary == 'html' && $plain) {
if ($part->ctype_secondary == 'html' && $p['plain']) {
$txt = new html2text($part->body, false, true);
$body = $txt->get_text();
$part->ctype_secondary = 'plain';
@ -553,25 +555,40 @@ function rcmail_print_body($part, $safe=false, $plain=false)
else if ($part->ctype_secondary == 'html') {
// charset was converted to UTF-8 in rcube_imap::get_message_part() -> change charset specification in HTML accordingly
$html = $part->body;
if(preg_match('/(\s+content=[\'"]\w+\/\w+;\s+charset)=([a-z0-9-]+)/i', $html))
$html = preg_replace('/(\s+content=[\'"]\w+\/\w+;\s+charset)=([a-z0-9-]+)/i', '\\1='.RCMAIL_CHARSET, $html);
if (preg_match('/(\s+content=[\'"]\w+\/\w+;\s*charset)=([a-z0-9-]+)/i', $html))
$html = preg_replace('/(\s+content=[\'"]\w+\/\w+;\s*charset)=([a-z0-9-]+)/i', '\\1='.RCMAIL_CHARSET, $html);
else {
// add <head> for malformed messages, washtml cannot work without that
if (!preg_match('/<head>(.*)<\/head>/m', $html))
if (!preg_match('/<head>(.*)<\\/head>/Uims', $html))
$html = '<head></head>' . $html;
$html = substr_replace($html, '<meta http-equiv="Content-Type" content="text/html; charset='.RCMAIL_CHARSET.'" />', intval(stripos($html, '</head>')), 0);
}
// clean HTML with washhtml by Frederic Motte
$body = washtml::wash($html, array(
$wash_opts = array(
'show_washed' => false,
'allow_remote' => $safe,
'allow_remote' => $p['safe'],
'blocked_src' => "./program/blocked.gif",
'charset' => RCMAIL_CHARSET,
'cid_map' => $part->replaces,
), $full_inline);
$REMOTE_OBJECTS = !$full_inline;
'html_elements' => array('body'),
);
if (!$p['inline_html']) {
$wash_opts['html_elements'] = array('html','head','title','body');
}
/* CSS styles need to be sanitized!
if ($p['safe']) {
$wash_opts['html_elements'][] = 'style';
$wash_opts['html_attribs'] = array('type');
}
*/
$washer = new washtml($wash_opts);
$washer->add_callback('form', 'rcmail_washtml_callback');
$body = $washer->wash($html);
$REMOTE_OBJECTS = $washer->extlinks;
return $body;
}
@ -637,21 +654,36 @@ function rcmail_print_body($part, $safe=false, $plain=false)
$body = preg_replace("/##string_replacement\{([0-9]+)\}##/e", "\$replace_strings[\\1]", join("\n", $a_lines));
return "<div class=\"pre\">".$body."\n</div>";
}
}
/**
* add a string to the replacement array and return a replacement string
*/
function rcmail_str_replacement($str, &$rep)
{
{
static $count = 0;
$rep[$count] = stripslashes($str);
return "##string_replacement{".($count++)."}##";
}
}
/**
* Callback function for washtml cleaning class
*/
function rcmail_washtml_callback($tagname, $attrib, $content)
{
switch ($tagname) {
case 'form':
$out = html::div('form', $content);
break;
default:
$out = '';
}
return $out;
}
/**
* return table with message headers
@ -756,7 +788,7 @@ function rcmail_message_body($attrib)
if (!isset($part->body))
$part->body = $MESSAGE->get_part_content($part->mime_id);
$body = rcmail_print_body($part, $safe_mode, !$CONFIG['prefer_html']);
$body = rcmail_print_body($part, array('safe' => $safe_mode, 'plain' => !$CONFIG['prefer_html']));
if ($part->ctype_secondary == 'html')
$out .= html::div('message-htmlpart', rcmail_html4inline($body, $attrib['id']));

4
program/steps/mail/get.inc
Unescape Escape View File

@ -65,6 +65,8 @@ else if ($pid = get_input_value('_part', RCUBE_INPUT_GET)) {
header("Cache-Control: private", false);
header("Content-Type: application/octet-stream");
}
else if ($ctype_primary == 'text')
header("Content-Type: text/$ctype_secondary; charset=" . RCMAIL_CHARSET);
else
header("Content-Type: $mimetype");
@ -95,7 +97,7 @@ else if ($pid = get_input_value('_part', RCUBE_INPUT_GET)) {
$part->body = $MESSAGE->get_part_content($part->mime_id);
$OUTPUT = new rcube_html_page();
$OUTPUT->write(rcmail_print_body($part, $MESSAGE->is_safe));
$OUTPUT->write(rcmail_print_body($part, array('safe' => $MESSAGE->is_safe, 'inline_html' => false)));
}
else {
header(sprintf('Content-Disposition: %s; filename="%s";',

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