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