cros: Replace "TPM" with "secure module" for machines without TPM.

chromeos/tpm/tpm_token_info_getter.cc

 // Copyright 2014 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 "chromeos/tpm/tpm_token_info_getter.h"
 
 #include <stdint.h>
 
 #include "base/bind.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
 #include "base/location.h"
 #include "base/task_runner.h"
 #include "chromeos/cryptohome/cryptohome_parameters.h"
 #include "chromeos/dbus/cryptohome_client.h"
 
 namespace {
 
 const int64_t kInitialRequestDelayMs = 100;
 const int64_t kMaxRequestDelayMs = 300000;  // 5 minutes
 
+// If either of these two files exist, then we are using Cr50 and not using TPM.
+constexpr char kCr50UsedIndicatorFile1[] =
+    "/opt/google/cr50/firmware/cr50.bin.prod";
+constexpr char kCr50UsedIndicatorFile2[] = "/etc/init/cr50-update.conf";
+
 // Calculates the delay before running next attempt to initiatialize the TPM
 // token, if |last_delay| was the last or initial delay.
 base::TimeDelta GetNextRequestDelayMs(base::TimeDelta last_delay) {
   // This implements an exponential backoff, as we don't know in which order of
   // magnitude the TPM token changes it's state.
   base::TimeDelta next_delay = last_delay * 2;
 
   // Cap the delay to prevent an overflow. This threshold is arbitrarily chosen.
   const base::TimeDelta max_delay =
       base::TimeDelta::FromMilliseconds(kMaxRequestDelayMs);
@@ skipping 24 matching lines @@
 }
 
 // static
 std::unique_ptr<TPMTokenInfoGetter> TPMTokenInfoGetter::CreateForSystemToken(
     CryptohomeClient* cryptohome_client,
     const scoped_refptr<base::TaskRunner>& delayed_task_runner) {
   return std::unique_ptr<TPMTokenInfoGetter>(new TPMTokenInfoGetter(
       TYPE_SYSTEM, EmptyAccountId(), cryptohome_client, delayed_task_runner));
 }
 
+bool TPMTokenInfoGetter::IsCr50Used() {
+  return base::PathExists(base::FilePath(kCr50UsedIndicatorFile1)) ||
+         base::PathExists(base::FilePath(kCr50UsedIndicatorFile2));

[xiyuan, 2017/05/03 04:06:49]

base::PathExists touches file system and should not be called from UI thread.
Also we might want to cache the info to avoid hitting FS everytime.

[sammiequon, 2017/05/04 16:04:47]

Done. Though I am concerned with not doing this properly.

+}
+
 TPMTokenInfoGetter::~TPMTokenInfoGetter() {}
 
 void TPMTokenInfoGetter::Start(const TPMTokenInfoCallback& callback) {
   CHECK(state_ == STATE_INITIAL);
   CHECK(!callback.is_null());
 
   callback_ = callback;
 
   state_ = STATE_STARTED;
   Continue();
@@ skipping 80 matching lines @@
   TPMTokenInfo token_info;
   token_info.tpm_is_enabled = true;
   token_info.token_name = token_name;
   token_info.user_pin = user_pin;
   token_info.token_slot_id = token_slot_id;
 
   callback_.Run(token_info);
 }
 
 }  // namespace chromeos