chromeos/tpm/tpm_password_fetcher.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "tpm_password_fetcher.h"
   6
   7 #include "base/bind.h"
   8 #include "base/compiler_specific.h"
   9 #include "base/location.h"
  10 #include "base/single_thread_task_runner.h"
  11 #include "base/thread_task_runner_handle.h"
  12 #include "chromeos/dbus/cryptohome_client.h"
  13 #include "chromeos/dbus/dbus_thread_manager.h"
  14
  15 namespace chromeos {
  16
  17 namespace {
  18
  19 // Interval between TPM password checks.
  20 const int kTpmCheckIntervalMs = 500;
  21
  22 }  // namespace
  23
  24 TpmPasswordFetcher::TpmPasswordFetcher(TpmPasswordFetcherDelegate* delegate)
  25     : delegate_(delegate), weak_factory_(this) {
  26   DCHECK(delegate_);
  27 }
  28
  29 TpmPasswordFetcher::~TpmPasswordFetcher() {
  30 }
  31
  32 void TpmPasswordFetcher::Fetch() {
  33   // Since this method is also called directly.
  34   weak_factory_.InvalidateWeakPtrs();
  35
  36   DBusThreadManager::Get()->GetCryptohomeClient()->TpmIsReady(base::Bind(
  37       &TpmPasswordFetcher::OnTpmIsReady, weak_factory_.GetWeakPtr()));
  38 }
  39
  40 void TpmPasswordFetcher::OnTpmIsReady(DBusMethodCallStatus call_status,
  41                                       bool tpm_is_ready) {
  42   if (call_status == DBUS_METHOD_CALL_SUCCESS && tpm_is_ready) {
  43     DBusThreadManager::Get()->GetCryptohomeClient()->TpmGetPassword(base::Bind(
  44         &TpmPasswordFetcher::OnTpmGetPassword, weak_factory_.GetWeakPtr()));
  45   } else {
  46     // Password hasn't been acquired, reschedule fetch.
  47     RescheduleFetch();
  48   }
  49 }
  50
  51 void TpmPasswordFetcher::OnTpmGetPassword(DBusMethodCallStatus call_status,
  52                                           const std::string& password) {
  53   if (call_status == DBUS_METHOD_CALL_SUCCESS) {
  54     if (password.empty()) {
  55       // For a fresh OOBE flow TPM is uninitialized,
  56       // ownership process is started at the EULA screen,
  57       // password is cleared after EULA is accepted.
  58       LOG(ERROR) << "TPM returned an empty password.";
  59     }
  60     delegate_->OnPasswordFetched(password);
  61   } else {
  62     // Password hasn't been acquired, reschedule fetch.
  63     RescheduleFetch();
  64   }
  65 }
  66
  67 void TpmPasswordFetcher::RescheduleFetch() {
  68   base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
  69       FROM_HERE,
  70       base::Bind(&TpmPasswordFetcher::Fetch, weak_factory_.GetWeakPtr()),
  71       base::TimeDelta::FromMilliseconds(kTpmCheckIntervalMs));
  72 }
  73
  74 }  // namespace chromeos