CSP: Experimentally harden against nonce-stealing injections.

third_party/WebKit/Source/core/dom/ScriptLoader.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, 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nikolas Zimmermann <zimmermann@kde.org>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 284 matching lines @@
         FetchRequest request(ResourceRequest(elementDocument->completeURL(sourceUrl)), m_element->localName());
 
         CrossOriginAttributeValue crossOrigin = crossOriginAttributeValue(m_element->fastGetAttribute(HTMLNames::crossoriginAttr));
         if (crossOrigin != CrossOriginAttributeNotSet)
             request.setCrossOriginAccessControl(elementDocument->getSecurityOrigin(), crossOrigin);
         request.setCharset(scriptCharset());
 
         // Skip fetch-related CSP checks if dynamically injected script is whitelisted and this script is not parser-inserted.
         bool scriptPassesCSPDynamic = (!isParserInserted() && elementDocument->contentSecurityPolicy()->allowDynamic());
 
-        request.setContentSecurityPolicyNonce(m_element->fastGetAttribute(HTMLNames::nonceAttr));
+        if (ContentSecurityPolicy::isNonceableElement(m_element.get()))
+            request.setContentSecurityPolicyNonce(m_element->fastGetAttribute(HTMLNames::nonceAttr));
 
         if (scriptPassesCSPDynamic) {
             UseCounter::count(elementDocument->frame(), UseCounter::ScriptPassesCSPDynamic);
             request.setContentSecurityCheck(DoNotCheckContentSecurityPolicy);
         }
         request.setDefer(defer);
 
         String integrityAttr = m_element->fastGetAttribute(HTMLNames::integrityAttr);
         if (!integrityAttr.isEmpty()) {
             IntegrityMetadataSet metadataSet;
@@ skipping 50 matching lines @@
     if (!contextDocument)
         return true;
 
     LocalFrame* frame = contextDocument->frame();
 
     const ContentSecurityPolicy* csp = elementDocument->contentSecurityPolicy();
     bool shouldBypassMainWorldCSP = (frame && frame->script().shouldBypassMainWorldCSP())
         || csp->allowScriptWithHash(sourceCode.source(), ContentSecurityPolicy::InlineType::Block)
         || (!isParserInserted() && csp->allowDynamic());
 
-    if (!m_isExternalScript && (!shouldBypassMainWorldCSP && !csp->allowInlineScript(elementDocument->url(), m_element->fastGetAttribute(HTMLNames::nonceAttr), m_startLineNumber, sourceCode.source()))) {
+    AtomicString nonce = ContentSecurityPolicy::isNonceableElement(m_element.get()) ? m_element->fastGetAttribute(HTMLNames::nonceAttr) : AtomicString();
+    if (!m_isExternalScript && (!shouldBypassMainWorldCSP && !csp->allowInlineScript(elementDocument->url(), nonce, m_startLineNumber, sourceCode.source()))) {
         return false;
     }
 
     if (m_isExternalScript) {
         ScriptResource* resource = m_resource ? m_resource.get() : sourceCode.resource();
         if (resource) {
             if (!resource->mimeTypeAllowedByNosniff()) {
                 contextDocument->addConsoleMessage(ConsoleMessage::create(SecurityMessageSource, ErrorMessageLevel, "Refused to execute script from '" + resource->url().elidedString() + "' because its MIME type ('" + resource->httpContentType() + "') is not executable, and strict MIME type checking is enabled."));
                 return false;
             }
@@ skipping 132 matching lines @@
     if (isHTMLScriptLoader(element))
         return toHTMLScriptElement(element)->loader();
 
     if (isSVGScriptLoader(element))
         return toSVGScriptElement(element)->loader();
 
     return 0;
 }
 
 } // namespace blink