Implementation of subresource integrity attribute for style sheets.

Source/core/html/HTMLLinkElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Rob Buis (rwlbuis@gmail.com)
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 24 matching lines @@
 #include "core/dom/Attribute.h"
 #include "core/dom/Document.h"
 #include "core/dom/StyleEngine.h"
 #include "core/events/Event.h"
 #include "core/events/EventSender.h"
 #include "core/fetch/CSSStyleSheetResource.h"
 #include "core/fetch/FetchRequest.h"
 #include "core/fetch/ResourceFetcher.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
+#include "core/frame/SubresourceIntegrity.h"
 #include "core/frame/csp/ContentSecurityPolicy.h"
 #include "core/html/LinkManifest.h"
 #include "core/html/imports/LinkImport.h"
 #include "core/loader/FrameLoader.h"
 #include "core/loader/FrameLoaderClient.h"
 #include "core/rendering/style/StyleInheritedData.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "wtf/StdLibExtras.h"
 
 namespace blink {
@@ skipping 439 matching lines @@
 Document& LinkStyle::document()
 {
     return m_owner->document();
 }
 
 void LinkStyle::setCSSStyleSheet(const String& href, const KURL& baseURL, const String& charset, const CSSStyleSheetResource* cachedStyleSheet)
 {
     if (!m_owner->inDocument()) {
         ASSERT(!m_sheet);
         return;
+    }
 
+    if (!SubresourceIntegrity::CheckSubresourceIntegrity(*m_owner, cachedStyleSheet->sheetText(), KURL(KURL(), href))) {
+        m_loading = false;
+        removePendingSheet();
+        return;
     }
+
     // Completing the sheet load may cause scripts to execute.
     RefPtrWillBeRawPtr<Node> protector(m_owner.get());
 
     CSSParserContext parserContext(m_owner->document(), 0, baseURL, charset);
 
     if (RefPtrWillBeRawPtr<StyleSheetContents> restoredSheet = const_cast<CSSStyleSheetResource*>(cachedStyleSheet)->restoreParsedStyleSheet(parserContext)) {
         ASSERT(restoredSheet->isCacheable());
         ASSERT(!restoredSheet->isLoading());
 
         if (m_sheet)
             clearSheet();
         m_sheet = CSSStyleSheet::create(restoredSheet, m_owner);
         m_sheet->setMediaQueries(MediaQuerySet::create(m_owner->media()));
         m_sheet->setTitle(m_owner->title());
 
         m_loading = false;
         restoredSheet->checkLoaded();
         return;
     }
 
     RefPtrWillBeRawPtr<StyleSheetContents> styleSheet = StyleSheetContents::create(href, parserContext);
 
     if (m_sheet)
         clearSheet();
+
     m_sheet = CSSStyleSheet::create(styleSheet, m_owner);
     m_sheet->setMediaQueries(MediaQuerySet::create(m_owner->media()));
     m_sheet->setTitle(m_owner->title());
 
     styleSheet->parseAuthorStyleSheet(cachedStyleSheet, m_owner->document().securityOrigin());
 
     m_loading = false;
     styleSheet->notifyLoadedSheet(cachedStyleSheet);
     styleSheet->checkLoaded();
 
@@ skipping 198 matching lines @@
         removePendingSheet();
 }
 
 void LinkStyle::trace(Visitor* visitor)
 {
     visitor->trace(m_sheet);
     LinkResource::trace(visitor);
 }
 
 } // namespace blink