src/chromeos/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/message_loop/message_loop.h"
  10 #include "chromeos/dbus/cryptohome_client.h"
  11 #include "chromeos/dbus/dbus_thread_manager.h"
  12
  13 namespace chromeos {
  14
  15 namespace {
  16
  17 // Interval between TPM password checks.
  18 const int kTpmCheckIntervalMs = 500;
  19
  20 }  // namespace
  21
  22 TpmPasswordFetcher::TpmPasswordFetcher(TpmPasswordFetcherDelegate* delegate)
  23     : delegate_(delegate), weak_factory_(this) {
  24   DCHECK(delegate_);
  25 }
  26
  27 TpmPasswordFetcher::~TpmPasswordFetcher() {
  28 }
  29
  30 void TpmPasswordFetcher::Fetch() {
  31   // Since this method is also called directly.
  32   weak_factory_.InvalidateWeakPtrs();
  33
  34   DBusThreadManager::Get()->GetCryptohomeClient()->TpmIsReady(base::Bind(
  35       &TpmPasswordFetcher::OnTpmIsReady, weak_factory_.GetWeakPtr()));
  36 }
  37
  38 void TpmPasswordFetcher::OnTpmIsReady(DBusMethodCallStatus call_status,
  39                                       bool tpm_is_ready) {
  40   if (call_status == DBUS_METHOD_CALL_SUCCESS && tpm_is_ready) {
  41     DBusThreadManager::Get()->GetCryptohomeClient()->TpmGetPassword(base::Bind(
  42         &TpmPasswordFetcher::OnTpmGetPassword, weak_factory_.GetWeakPtr()));
  43   } else {
  44     // Password hasn't been acquired, reschedule fetch.
  45     RescheduleFetch();
  46   }
  47 }
  48
  49 void TpmPasswordFetcher::OnTpmGetPassword(DBusMethodCallStatus call_status,
  50                                           const std::string& password) {
  51   if (call_status == DBUS_METHOD_CALL_SUCCESS) {
  52     if (password.empty()) {
  53       // For a fresh OOBE flow TPM is uninitialized,
  54       // ownership process is started at the EULA screen,
  55       // password is cleared after EULA is accepted.
  56       LOG(ERROR) << "TPM returned an empty password.";
  57     }
  58     delegate_->OnPasswordFetched(password);
  59   } else {
  60     // Password hasn't been acquired, reschedule fetch.
  61     RescheduleFetch();
  62   }
  63 }
  64
  65 void TpmPasswordFetcher::RescheduleFetch() {
  66   base::MessageLoop::current()->PostDelayedTask(
  67       FROM_HERE,
  68       base::Bind(&TpmPasswordFetcher::Fetch, weak_factory_.GetWeakPtr()),
  69       base::TimeDelta::FromMilliseconds(kTpmCheckIntervalMs));
  70 }
  71
  72 }  // namespace chromeos