Misc. warning fixes/cleanup

components/nacl/loader/nacl_ipc_adapter.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 "components/nacl/loader/nacl_ipc_adapter.h"
 
 #include <limits.h>
 #include <string.h>
 
 #include "base/basictypes.h"
@@ skipping 806 matching lines @@
   // There is some padding in this structure (the "padding" member is 16
   // bits but this then gets padded to 32 bits). We want to be sure not to
   // leak data to the untrusted plugin, so zero everything out first.
   NaClMessageHeader header;
   memset(&header, 0, sizeof(NaClMessageHeader));
 
   header.payload_size = static_cast<uint32>(msg.payload_size());
   header.routing = msg.routing_id();
   header.type = msg.type();
   header.flags = msg.flags();
-  header.num_fds = static_cast<int>(rewritten_msg->desc_count());
+  header.num_fds = static_cast<uint16>(rewritten_msg->desc_count());

[Peter Kasting, 2014/12/06 00:12:18]

What if desc_count() doesn't fit in a uint16?  Is that possible?  Should we
checked_cast<> here?

[bbudge, 2014/12/06 01:30:28]

These messages are from the renderer or browser processes, so I think the number
of fds is very small (1 or 2 at most) and we don't worry about attacks from this
direction.

 
   rewritten_msg->SetData(header, msg.payload(), msg.payload_size());
   locked_data_.to_be_received_.push(rewritten_msg);
 }
 
 int TranslatePepperFileReadWriteOpenFlagsForTesting(int32_t pp_open_flags) {
   return TranslatePepperFileReadWriteOpenFlags(pp_open_flags);
 }