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). If TPM is
  37     // disabled, |tpm_user_pin|, |tpm_token_name| and |tpm_token_slot_id| will
  38     // not be set.
  39     virtual void OnTPMTokenReady(const std::string& tpm_user_pin,
  40                                  const std::string& tpm_token_name,
  41                                  int tpm_token_slot_id) = 0;
  42
  43    protected:
  44     virtual ~Observer() {}
  45   };
  46
  47   // Sets the global instance. Must be called before any calls to Get().
  48   // The global instance will immediately start observing |LoginState|.
  49   static void Initialize();
  50
  51   // Destroys the global instance.
  52   static void Shutdown();
  53
  54   // Gets the global instance. Initialize() must be called before this.
  55   static TPMTokenLoader* Get();
  56
  57   // Returns true if the global instance has been initialized.
  58   static bool IsInitialized();
  59
  60   // By default, TPMTokenLoader tries to load the TPMToken only if running
  61   // in a ChromeOS environment. Tests can call this function after Initialize()
  62   // and before SetCryptoTaskRunner() to enable the TPM initialization.
  63   void InitializeTPMForTest();
  64
  65   // |crypto_task_runner| is the task runner that any synchronous crypto calls
  66   // should be made from, e.g. in Chrome this is the IO thread. Must be called
  67   // after the thread is started. When called, this will attempt to start TPM
  68   // token loading.
  69   void SetCryptoTaskRunner(
  70       const scoped_refptr<base::SequencedTaskRunner>& crypto_task_runner);
  71
  72   void AddObserver(TPMTokenLoader::Observer* observer);
  73   void RemoveObserver(TPMTokenLoader::Observer* observer);
  74
  75   // Checks if the TPM token in ready to be used.
  76   bool IsTPMTokenReady() const;
  77
  78  private:
  79   TPMTokenLoader();
  80   virtual ~TPMTokenLoader();
  81
  82   // Starts tpm token initialization if the user is logged in and the crypto
  83   // task runner is set.
  84   void MaybeStartTokenInitialization();
  85
  86   // This is the cyclic chain of callbacks to initialize the TPM token.
  87   void ContinueTokenInitialization();
  88   void OnPersistentNSSDBOpened();
  89   void OnTpmIsEnabled(DBusMethodCallStatus call_status,
  90                       bool tpm_is_enabled);
  91   void OnPkcs11IsTpmTokenReady(DBusMethodCallStatus call_status,
  92                                bool is_tpm_token_ready);
  93   void OnPkcs11GetTpmTokenInfo(DBusMethodCallStatus call_status,
  94                                const std::string& token_name,
  95                                const std::string& user_pin,
  96                                int token_slot_id);
  97   void OnTPMTokenInitialized(bool success);
  98
  99   // If token initialization step fails (e.g. if tpm token is not yet ready)
 100   // schedules the initialization step retry attempt after a timeout.
 101   void RetryTokenInitializationLater();
 102
 103   // Notifies observers that the TPM token is ready.
 104   void NotifyTPMTokenReady();
 105
 106   // LoginState::Observer
 107   virtual void LoggedInStateChanged() OVERRIDE;
 108
 109   bool initialize_tpm_for_test_;
 110
 111   ObserverList<Observer> observers_;
 112
 113   // The states are traversed in this order but some might get omitted or never
 114   // be left.
 115   enum TPMTokenState {
 116     TPM_STATE_UNKNOWN,
 117     TPM_INITIALIZATION_STARTED,
 118     TPM_DB_OPENED,
 119     TPM_DISABLED,
 120     TPM_ENABLED,
 121     TPM_TOKEN_READY,
 122     TPM_TOKEN_INFO_RECEIVED,
 123     TPM_TOKEN_INITIALIZED,
 124   };
 125   TPMTokenState tpm_token_state_;
 126
 127   // The current request delay before the next attempt to initialize the
 128   // TPM. Will be adapted after each attempt.
 129   base::TimeDelta tpm_request_delay_;
 130
 131   // Cached TPM token info.
 132   std::string tpm_token_name_;
 133   int tpm_token_slot_id_;
 134   std::string tpm_user_pin_;
 135
 136   base::ThreadChecker thread_checker_;
 137
 138   // TaskRunner for crypto calls.
 139   scoped_refptr<base::SequencedTaskRunner> crypto_task_runner_;
 140
 141   base::WeakPtrFactory<TPMTokenLoader> weak_factory_;
 142
 143   DISALLOW_COPY_AND_ASSIGN(TPMTokenLoader);
 144 };
 145
 146 }  // namespace chromeos
 147
 148 #endif  // CHROMEOS_TPM_TOKEN_LOADER_H_