Fix remoting NM hosts to verify that incoming messages are dictionaries.

remoting/host/it2me/it2me_native_messaging_host.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "remoting/host/it2me/it2me_native_messaging_host.h"
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
@@ skipping 69 matching lines @@
   DCHECK(!quit_closure.is_null());
 
   quit_closure_ = quit_closure;
 
   channel_->Start(this);
 }
 
 void It2MeNativeMessagingHost::OnMessage(scoped_ptr<base::Value> message) {
   DCHECK(task_runner()->BelongsToCurrentThread());
 
+  if (message->GetType() != base::Value::TYPE_DICTIONARY) {
+    LOG(ERROR) << "Received a message that's not a dictionary.";
+    channel_->SendMessage(nullptr);
+    return;
+  }
+
   scoped_ptr<base::DictionaryValue> message_dict(
       static_cast<base::DictionaryValue*>(message.release()));
   scoped_ptr<base::DictionaryValue> response(new base::DictionaryValue());
 
   // If the client supplies an ID, it will expect it in the response. This
   // might be a string or a number, so cope with both.
   const base::Value* id;
   if (message_dict->Get("id", &id))
     response->Set("id", id->DeepCopy());
 
@@ skipping 203 matching lines @@
 }
 
 /* static */
 std::string It2MeNativeMessagingHost::HostStateToString(
     It2MeHostState host_state) {
   return ValueToName(kIt2MeHostStates, host_state);
 }
 
 }  // namespace remoting