From e7b4b73969b02708142321001c1979f0c398ef8e Mon Sep 17 00:00:00 2001
From: Johannes Hofmann <Johannes.Hofmann@gmx.de>
Date: Sat, 21 Jan 2012 22:34:33 +0100
Subject: ignore remote CSS rules that could reveal browser history

For a discussion of the problem see:
http://dbaron.org/mozilla/visited-privacy
---
 src/css.cc | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

(limited to 'src/css.cc')

diff --git a/src/css.cc b/src/css.cc
index c6c74f60..8cf1c8eb 100644
--- a/src/css.cc
+++ b/src/css.cc
@@ -27,6 +27,7 @@ CssPropertyList::CssPropertyList (const CssPropertyList &p, bool deep) :
    lout::misc::SimpleVector <CssProperty> (p)
 {
    refCount = 0;
+   safe = p.safe;
    if (deep) {
       for (int i = 0; i < size (); i++) {
          CssProperty *p = getRef(i);
@@ -58,6 +59,9 @@ void CssPropertyList::set (CssPropertyName name, CssValueType type,
                            CssPropertyValue value) {
    CssProperty *prop;
 
+   if (name == CSS_PROPERTY_DISPLAY || name == CSS_PROPERTY_BACKGROUND_IMAGE)
+      safe = false;
+
    for (int i = 0; i < size (); i++) {
       prop = getRef (i);
 
@@ -169,6 +173,13 @@ void CssSelector::addSimpleSelector (Combinator c) {
    cs->selector = new CssSimpleSelector ();
 }
 
+bool CssSelector::checksPseudoClass () {
+   for (int i = 0; i < selectorList->size (); i++)
+      if (selectorList->getRef (i)->selector->getPseudoClass ())
+         return true;
+   return false;
+}
+
 /**
  * \brief Return the specificity of the selector.
  *
@@ -517,6 +528,13 @@ void CssContext::addRule (CssSelector *sel, CssPropertyList *props,
    if (props->size () > 0) {
       CssRule *rule = new CssRule (sel, props, pos++);
 
-      sheet[order].addRule (rule);
+      if ((order == CSS_PRIMARY_AUTHOR ||
+           order == CSS_PRIMARY_AUTHOR_IMPORTANT) &&
+           !rule->isSafe ()) {
+         MSG_WARN ("Ignoring unsafe author style that might reveal browsing history\n");
+         delete rule;
+      } else {
+         sheet[order].addRule (rule);
+      }
    }
 }
-- 
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