[mojo-edk] Invalidate message handle when rewrite fails

mojo/edk/system/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/channel.h"
 
 #include <string.h>
 
 #include <algorithm>
 #include <limits>
@@ skipping 318 matching lines @@
   for (size_t i = 0; i < num_handles; ++i) {
     if (!handles[i].is_valid()) {
       DLOG(ERROR) << "Refusing to duplicate invalid handle.";
       continue;
     }
     DCHECK_EQ(handles[i].owning_process, from_process);
     BOOL result = DuplicateHandle(
         from_process, handles[i].handle, to_process,
         &handles[i].handle, 0, FALSE,
         DUPLICATE_SAME_ACCESS | DUPLICATE_CLOSE_SOURCE);
-    if (result)
+    if (result) {
       handles[i].owning_process = to_process;
-    else
+    } else {
       success = false;
+
+      // If handle duplication fails, the source handle will already be closed
+      // due to DUPLICATE_CLOSE_SOURCE. Replace the handle in the message with
+      // an invalid handle.
+      handles[i].handle = INVALID_HANDLE_VALUE;
+      handles[i].owning_process = base::GetCurrentProcessHandle();
+    }
   }
   return success;
 }
 #endif
 
 // Helper class for managing a Channel's read buffer allocations. This maintains
 // a single contiguous buffer with the layout:
 //
 //   [discarded bytes][occupied bytes][unoccupied bytes]
 //
@@ skipping 208 matching lines @@
   return true;
 }
 
 void Channel::OnError() {
   if (delegate_)
     delegate_->OnChannelError();
 }
 
 }  // namespace edk
 }  // namespace mojo