chromeos/tpm_token_loader.h

   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
  20 namespace base {
  21 class SequencedTaskRunner;
  22 }
  23
  24 namespace 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|.
  31 class 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_