[mojo-edk] Add some buffer checks and fix UAF on NodeChannel

mojo/edk/system/data_pipe_consumer_dispatcher.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 "mojo/edk/system/data_pipe_consumer_dispatcher.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 517 matching lines @@
   }
 
   if (port_status.has_messages && !in_transit_) {
     ports::ScopedMessage message;
     do {
       int rv = node_controller_->node()->GetMessageIf(control_port_, nullptr,
                                                       &message);
       if (rv != ports::OK)
         peer_closed_ = true;
       if (message) {
+        if (message->num_payload_bytes() < sizeof(DataPipeControlMessage)) {
+          peer_closed_ = true;
+          break;
+        }
+
         const DataPipeControlMessage* m =
             static_cast<const DataPipeControlMessage*>(
                 message->payload_bytes());
 
         if (m->command != DataPipeCommand::DATA_WAS_WRITTEN) {
           DLOG(ERROR) << "Unexpected control message from producer.";
           peer_closed_ = true;
           break;
         }
 
@@ skipping 14 matching lines @@
   }
 
   if (peer_closed_ != was_peer_closed ||
       bytes_available_ != previous_bytes_available) {
     awakable_list_.AwakeForStateChange(GetHandleSignalsStateNoLock());
   }
 }
 
 }  // namespace edk
 }  // namespace mojo