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#ifndef CHROMEOS_TPM_TOKEN_LOADER_H_
6#define CHROMEOS_TPM_TOKEN_LOADER_H_
7
8#include <string>
9
10#include "base/basictypes.h"
11#include "base/memory/ref_counted.h"
12#include "base/memory/weak_ptr.h"
13#include "base/observer_list.h"
14#include "base/threading/thread_checker.h"
15#include "base/time/time.h"
16#include "chromeos/chromeos_export.h"
17#include "chromeos/dbus/dbus_method_call_status.h"
18#include "chromeos/login/login_state.h"
19
20namespace base {
21class SequencedTaskRunner;
22}
23
24namespace chromeos {
25
26// This class is responsible for loading the TPM token when the user logs
27// in. It is expected to be constructed on the UI thread and public methods
28// should all be called from the UI thread. When the TPM token is loaded,
29// or if the TPM should stay disabled for the session, the observers are
30// notified using |OnTPMTokenReady|.
31class CHROMEOS_EXPORT TPMTokenLoader : public LoginState::Observer {
32 public:
33  class Observer {
34   public:
35    // Called when the TPM token initialization is done or the case where TPM
36    // should stay disabled is detected (e.g. on guest login).
37    virtual void OnTPMTokenReady() = 0;
38
39   protected:
40    virtual ~Observer() {}
41  };
42
43  // Sets the global instance. Must be called before any calls to Get().
44  // The global instance will immediately start observing |LoginState|.
45  static void Initialize();
46
47  // Sets the global. stubbed out, instance. To be used in tests.
48  static void InitializeForTest();
49
50  // Destroys the global instance.
51  static void Shutdown();
52
53  // Gets the global instance. Initialize() must be called before this.
54  static TPMTokenLoader* Get();
55
56  // Returns true if the global instance has been initialized.
57  static bool IsInitialized();
58
59  // |crypto_task_runner| is the task runner that any synchronous crypto calls
60  // should be made from, e.g. in Chrome this is the IO thread. Must be called
61  // after the thread is started. When called, this will attempt to start TPM
62  // token loading.
63  void SetCryptoTaskRunner(
64      const scoped_refptr<base::SequencedTaskRunner>& crypto_task_runner);
65
66  void AddObserver(TPMTokenLoader::Observer* observer);
67  void RemoveObserver(TPMTokenLoader::Observer* observer);
68
69  // Checks if the TPM token in ready to be used.
70  bool IsTPMTokenReady() const;
71
72  std::string tpm_user_pin() const { return tpm_user_pin_; }
73
74 private:
75  explicit TPMTokenLoader(bool for_test);
76  virtual ~TPMTokenLoader();
77
78  // Starts tpm token initialization if the user is logged in and the crypto
79  // task runner is set.
80  void MaybeStartTokenInitialization();
81
82  // This is the cyclic chain of callbacks to initialize the TPM token.
83  void ContinueTokenInitialization();
84  void OnPersistentNSSDBOpened();
85  void OnTpmIsEnabled(DBusMethodCallStatus call_status,
86                      bool tpm_is_enabled);
87  void OnPkcs11IsTpmTokenReady(DBusMethodCallStatus call_status,
88                               bool is_tpm_token_ready);
89  void OnPkcs11GetTpmTokenInfo(DBusMethodCallStatus call_status,
90                               const std::string& token_name,
91                               const std::string& user_pin,
92                               int token_slot_id);
93  void OnTPMTokenInitialized(bool success);
94
95  // If token initialization step fails (e.g. if tpm token is not yet ready)
96  // schedules the initialization step retry attempt after a timeout.
97  void RetryTokenInitializationLater();
98
99  // Notifies observers that the TPM token is ready.
100  void NotifyTPMTokenReady();
101
102  // LoginState::Observer
103  virtual void LoggedInStateChanged() OVERRIDE;
104
105  bool initialized_for_test_;
106
107  ObserverList<Observer> observers_;
108
109  // The states are traversed in this order but some might get omitted or never
110  // be left.
111  enum TPMTokenState {
112    TPM_STATE_UNKNOWN,
113    TPM_INITIALIZATION_STARTED,
114    TPM_DB_OPENED,
115    TPM_DISABLED,
116    TPM_ENABLED,
117    TPM_TOKEN_READY,
118    TPM_TOKEN_INFO_RECEIVED,
119    TPM_TOKEN_INITIALIZED,
120  };
121  TPMTokenState tpm_token_state_;
122
123  // The current request delay before the next attempt to initialize the
124  // TPM. Will be adapted after each attempt.
125  base::TimeDelta tpm_request_delay_;
126
127  // Cached TPM token info.
128  std::string tpm_token_name_;
129  int tpm_token_slot_id_;
130  std::string tpm_user_pin_;
131
132  base::ThreadChecker thread_checker_;
133
134  // TaskRunner for crypto calls.
135  scoped_refptr<base::SequencedTaskRunner> crypto_task_runner_;
136
137  base::WeakPtrFactory<TPMTokenLoader> weak_factory_;
138
139  DISALLOW_COPY_AND_ASSIGN(TPMTokenLoader);
140};
141
142}  // namespace chromeos
143
144#endif  // CHROMEOS_TPM_TOKEN_LOADER_H_
145