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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.
#ifndef CHROMEOS_TPM_TOKEN_LOADER_H_
#define CHROMEOS_TPM_TOKEN_LOADER_H_
#include <string>
#include "base/basictypes.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 "base/time/time.h"
#include "chromeos/chromeos_export.h"
#include "chromeos/dbus/dbus_method_call_status.h"
#include "chromeos/login/login_state.h"
namespace base {
class SequencedTaskRunner;
}
namespace chromeos {
// 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 {
public:
class Observer {
public:
// Called when the TPM token initialization is done or the case where TPM
// should stay disabled is detected (e.g. on guest login).
virtual void OnTPMTokenReady() = 0;
protected:
virtual ~Observer() {}
};
// 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);
void AddObserver(TPMTokenLoader::Observer* observer);
void RemoveObserver(TPMTokenLoader::Observer* observer);
// Checks if the TPM token in ready to be used.
bool IsTPMTokenReady() const;
std::string tpm_user_pin() const { return tpm_user_pin_; }
private:
explicit TPMTokenLoader(bool for_test);
virtual ~TPMTokenLoader();
// 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 OnTpmIsEnabled(DBusMethodCallStatus call_status,
bool tpm_is_enabled);
void OnPkcs11IsTpmTokenReady(DBusMethodCallStatus call_status,
bool is_tpm_token_ready);
void OnPkcs11GetTpmTokenInfo(DBusMethodCallStatus call_status,
const std::string& token_name,
const std::string& user_pin,
int token_slot_id);
void OnTPMTokenInitialized(bool success);
// If token initialization step fails (e.g. if tpm token is not yet ready)
// schedules the initialization step retry attempt after a timeout.
void RetryTokenInitializationLater();
// Notifies observers that the TPM token is ready.
void NotifyTPMTokenReady();
// LoginState::Observer
virtual void LoggedInStateChanged() OVERRIDE;
bool initialized_for_test_;
ObserverList<Observer> observers_;
// The states are traversed in this order but some might get omitted or never
// be left.
enum TPMTokenState {
TPM_STATE_UNKNOWN,
TPM_INITIALIZATION_STARTED,
TPM_TOKEN_ENABLED_FOR_NSS,
TPM_DISABLED,
TPM_ENABLED,
TPM_TOKEN_READY,
TPM_TOKEN_INFO_RECEIVED,
TPM_TOKEN_INITIALIZED,
};
TPMTokenState tpm_token_state_;
// The current request delay before the next attempt to initialize the
// TPM. Will be adapted after each attempt.
base::TimeDelta tpm_request_delay_;
// Cached TPM token info.
std::string tpm_token_name_;
int tpm_token_slot_id_;
std::string tpm_user_pin_;
base::ThreadChecker thread_checker_;
// TaskRunner for crypto calls.
scoped_refptr<base::SequencedTaskRunner> crypto_task_runner_;
base::WeakPtrFactory<TPMTokenLoader> weak_factory_;
DISALLOW_COPY_AND_ASSIGN(TPMTokenLoader);
};
} // namespace chromeos
#endif // CHROMEOS_TPM_TOKEN_LOADER_H_