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      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_
    145