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// 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 <memory>
#include <string>
#include <vector>
#include "base/callback_forward.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/observer_list.h"
#include "base/threading/thread_checker.h"
#include "chromeos/chromeos_export.h"
#include "chromeos/login/login_state.h"
namespace base {
class SequencedTaskRunner;
namespace chromeos {
struct TPMTokenInfo;
class TPMTokenInfoGetter;
// This class is responsible for loading the TPM backed token for the system
// slot when the user logs in. It is expected to be constructed on the UI thread
// and public methods should all be called from the UI thread.
// When the TPM token is loaded, or if the TPM should stay disabled for the
// session, the observers are notified using |OnTPMTokenReady|.
// Note: This currently initializes the token with the hard coded default id 0.
// See CryptohomeClient::OnPkcs11GetTpmTokenInfo.
class CHROMEOS_EXPORT TPMTokenLoader : public LoginState::Observer {
enum TPMTokenStatus {
typedef base::Callback<void(bool)> TPMReadyCallback;
typedef std::vector<TPMReadyCallback> TPMReadyCallbackList;
// Sets the global instance. Must be called before any calls to Get().
// The global instance will immediately start observing |LoginState|.
static void Initialize();
// Sets the global. stubbed out, instance. To be used in tests.
static void InitializeForTest();
// Destroys the global instance.
static void Shutdown();
// Gets the global instance. Initialize() must be called before this.
static TPMTokenLoader* Get();
// Returns true if the global instance has been initialized.
static bool IsInitialized();
// |crypto_task_runner| is the task runner that any synchronous crypto calls
// should be made from, e.g. in Chrome this is the IO thread. Must be called
// after the thread is started. When called, this will attempt to start TPM
// token loading.
void SetCryptoTaskRunner(
const scoped_refptr<base::SequencedTaskRunner>& crypto_task_runner);
// Starts loading TPM system token, if not yet started. It should be called
// if the system token has to be loaded before a user logs in. By default (if
// |EnsureStarted| is not called) system token loading will start when the
// login state changes to LOGGED_IN_ACTIVE.
void EnsureStarted();
// Checks if the TPM token is enabled. If the state is unknown, |callback|
// will be called back once the TPM state is known.
TPMTokenStatus IsTPMTokenEnabled(const TPMReadyCallback& callback);
std::string tpm_user_pin() const { return tpm_user_pin_; }
explicit TPMTokenLoader(bool for_test);
~TPMTokenLoader() override;
bool IsTPMLoadingEnabled() const;
// Starts tpm token initialization if the user is logged in and the crypto
// task runner is set.
void MaybeStartTokenInitialization();
// This is the cyclic chain of callbacks to initialize the TPM token.
void ContinueTokenInitialization();
void OnTPMTokenEnabledForNSS();
void OnGotTpmTokenInfo(const TPMTokenInfo& token_info);
void OnTPMTokenInitialized(bool success);
// Notifies observers that the TPM token is ready.
void NotifyTPMTokenReady();
// LoginState::Observer
void LoggedInStateChanged() override;
bool initialized_for_test_;
TPMReadyCallbackList tpm_ready_callback_list_;
// The states are traversed in this order but some might get omitted or never
// be left.
enum TPMTokenState {
TPMTokenState tpm_token_state_;
std::unique_ptr<TPMTokenInfoGetter> tpm_token_info_getter_;
// Cached TPM token info.
int tpm_token_slot_id_;
std::string tpm_user_pin_;
// Whether TPM system token loading may be started before user log in.
// This will be true iff |EnsureStarted| was called.
bool can_start_before_login_;
base::ThreadChecker thread_checker_;
// TaskRunner for crypto calls.
scoped_refptr<base::SequencedTaskRunner> crypto_task_runner_;
base::WeakPtrFactory<TPMTokenLoader> weak_factory_;
} // namespace chromeos