[mojo-edk] Fix lifetime management of rewritten Windows HANDLEs

mojo/edk/system/node_channel.cc

 // Copyright 2016 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/node_channel.h"
 
 #include <cstring>
 #include <limits>
 #include <sstream>
 
@@ skipping 376 matching lines @@
 
   RequestContext request_context(RequestContext::Source::SYSTEM);
 
 #if defined(OS_WIN)
   // If we receive handles from a known process, rewrite them to our own
   // process. This can occur when a privileged node receives handles directly
   // from a privileged descendant.
   {
     base::AutoLock lock(remote_process_handle_lock_);
     if (handles && remote_process_handle_ != base::kNullProcessHandle) {
+      // Note that we explicitly mark the handles as being owned by the sending
+      // process before rewriting them, in order to accommodate RewriteHandles'
+      // internal sanity checks.
+      for (auto& handle : *handles)
+        handle.owning_process = remote_process_handle_;
       if (!Channel::Message::RewriteHandles(remote_process_handle_,
                                             base::GetCurrentProcessHandle(),
                                             handles->data(), handles->size())) {
         DLOG(ERROR) << "Received one or more invalid handles.";
       }
+    } else if (handles) {
+      // Handles received by an unknown process must already be owned by us.
+      for (auto& handle : *handles)
+        handle.owning_process = base::GetCurrentProcessHandle();
     }
   }
 #elif defined(OS_MACOSX) && !defined(OS_IOS)
   // If we're not the root, receive any mach ports from the message. If we're
   // the root, the only message containing mach ports should be a
   // RELAY_PORTS_MESSAGE.
   {
     MachPortRelay* relay = delegate_->GetMachPortRelay();
     if (handles && !relay) {
       if (!MachPortRelay::ReceivePorts(handles.get())) {
@@ skipping 299 matching lines @@
 
   base::AutoLock lock(channel_lock_);
   if (!channel_)
     DLOG(ERROR) << "Dropping message on closed channel.";
   else
     channel_->Write(std::move(message));
 }
 
 }  // namespace edk
 }  // namespace mojo