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-rw-r--r--program/include/main.inc34
1 files changed, 24 insertions, 10 deletions
diff --git a/program/include/main.inc b/program/include/main.inc
index 714764959..d40dbda9a 100644
--- a/program/include/main.inc
+++ b/program/include/main.inc
@@ -883,23 +883,37 @@ function rcmail_get_edit_field($col, $value, $attrib, $type='text')
* @param string Container ID to use as prefix
* @return string Modified CSS source
*/
-function rcmail_mod_css_styles($source, $container_id)
+function rcmail_mod_css_styles($source, $container_id, $allow_remote=false)
{
$last_pos = 0;
$replacements = new rcube_string_replacer;
// ignore the whole block if evil styles are detected
- $stripped = preg_replace('/[^a-z\(:;]/', '', rcmail_xss_entity_decode($source));
- if (preg_match('/expression|behavior|url\(|import[^a]/', $stripped))
+ $source = rcmail_xss_entity_decode($source);
+ $stripped = preg_replace('/[^a-z\(:;]/i', '', $source);
+ $evilexpr = 'expression|behavior|javascript:|import[^a]' . (!$allow_remote ? '|url\(' : '');
+ if (preg_match("/$evilexpr/i", $stripped))
return '/* evil! */';
- // remove css comments (sometimes used for some ugly hacks)
- $source = preg_replace('!/\*(.+)\*/!Ums', '', $source);
-
// cut out all contents between { and }
- while (($pos = strpos($source, '{', $last_pos)) && ($pos2 = strpos($source, '}', $pos)))
- {
- $key = $replacements->add(substr($source, $pos+1, $pos2-($pos+1)));
+ while (($pos = strpos($source, '{', $last_pos)) && ($pos2 = strpos($source, '}', $pos))) {
+ $styles = substr($source, $pos+1, $pos2-($pos+1));
+
+ // check every line of a style block...
+ if ($allow_remote) {
+ $a_styles = preg_split('/;[\r\n]*/', $styles, -1, PREG_SPLIT_NO_EMPTY);
+ foreach ($a_styles as $line) {
+ $stripped = preg_replace('/[^a-z\(:;]/i', '', $line);
+ // ... and only allow strict url() values
+ if (stripos($stripped, 'url(') && !preg_match('!url\s*\([ "\'](https?:)//[a-z0-9/._+-]+["\' ]\)!Uims', $line)) {
+ $a_styles = array('/* evil! */');
+ break;
+ }
+ }
+ $styles = join(";\n", $a_styles);
+ }
+
+ $key = $replacements->add($styles);
$source = substr($source, 0, $pos+1) . $replacements->get_replacement($key) . substr($source, $pos2, strlen($source)-$pos2);
$last_pos = $pos+2;
}
@@ -937,7 +951,7 @@ function rcmail_xss_entity_decode($content)
{
$out = html_entity_decode(html_entity_decode($content));
$out = preg_replace_callback('/\\\([0-9a-f]{4})/i', 'rcmail_xss_entity_decode_callback', $out);
- $out = preg_replace('#/\*.*\*/#Um', '', $out);
+ $out = preg_replace('#/\*.*\*/#Ums', '', $out);
return $out;
}