Use the NSS internal key slot for all temporary key operations

crypto/encryptor_nss.cc

 // Copyright (c) 2011 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 "crypto/encryptor.h"
 
 #include <cryptohi.h>
 #include <vector>
 
 #include "base/logging.h"
@@ skipping 35 matching lines @@
                      const base::StringPiece& iv) {
   DCHECK(key);
   DCHECK(CBC == mode || CTR == mode) << "Unsupported mode of operation";
 
   key_ = key;
   mode_ = mode;
 
   if (mode == CBC && iv.size() != AES_BLOCK_SIZE)
     return false;
 
-  slot_.reset(PK11_GetBestSlot(GetMechanism(mode), NULL));
+  slot_.reset(PK11_GetInternalSlot());

[Ryan Sleevi, 2012/10/16 19:25:09]

wtc: It's not immediately clear to me why we even initialize slot_, since it
appears unused (PK11_CreateContextBySymKey will attempt to use the keys' slot).
Was this just meant to see if the mechanism was supported?

If so, should we be probing key's slot directly then?

[wtc, 2012/10/16 21:26:57]

We should remove the unused slot_ member. I guess this
was a code-copying mistake.

   if (!slot_.get())
     return false;
 
   switch (mode) {
     case CBC:
       SECItem iv_item;
       iv_item.type = siBuffer;
       iv_item.data = reinterpret_cast<unsigned char*>(
           const_cast<char *>(iv.data()));
       iv_item.len = iv.size();
@@ skipping 121 matching lines @@
 
   // Use |output_data| to mask |input|.
   MaskMessage(
       reinterpret_cast<uint8*>(const_cast<char*>(input.data())),
       input.length(), output_data, output_data);
   output->resize(input.length());
   return true;
 }
 
 }  // namespace crypto