chromeos/tpm/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_TPM_TOKEN_LOADER_H_
   6 #define CHROMEOS_TPM_TPM_TOKEN_LOADER_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "base/memory/ref_counted.h"
  13 #include "base/memory/weak_ptr.h"
  14 #include "base/observer_list.h"
  15 #include "base/threading/thread_checker.h"
  16 #include "chromeos/chromeos_export.h"
  17 #include "chromeos/login/login_state.h"
  18
  19 namespace base {
  20 class SequencedTaskRunner;
  21 }
  22
  23 namespace chromeos {
  24
  25 struct TPMTokenInfo;
  26 class TPMTokenInfoGetter;
  27
  28 // This class is responsible for loading the TPM backed token for the system
  29 // slot when the user logs in. It is expected to be constructed on the UI thread
  30 // and public methods should all be called from the UI thread.
  31 // When the TPM token is loaded, or if the TPM should stay disabled for the
  32 // session, the observers are notified using |OnTPMTokenReady|.
  33 // Note: This currently initializes the token with the hard coded default id 0.
  34 // See CryptohomeClient::OnPkcs11GetTpmTokenInfo.
  35 class CHROMEOS_EXPORT TPMTokenLoader : public LoginState::Observer {
  36  public:
  37   enum TPMTokenStatus {
  38     TPM_TOKEN_STATUS_UNDETERMINED,
  39     TPM_TOKEN_STATUS_ENABLED,
  40     TPM_TOKEN_STATUS_DISABLED
  41   };
  42
  43   typedef base::Callback<void(bool)> TPMReadyCallback;
  44   typedef std::vector<TPMReadyCallback> TPMReadyCallbackList;
  45
  46   // Sets the global instance. Must be called before any calls to Get().
  47   // The global instance will immediately start observing |LoginState|.
  48   static void Initialize();
  49
  50   // Sets the global. stubbed out, instance. To be used in tests.
  51   static void InitializeForTest();
  52
  53   // Destroys the global instance.
  54   static void Shutdown();
  55
  56   // Gets the global instance. Initialize() must be called before this.
  57   static TPMTokenLoader* Get();
  58
  59   // Returns true if the global instance has been initialized.
  60   static bool IsInitialized();
  61
  62   // |crypto_task_runner| is the task runner that any synchronous crypto calls
  63   // should be made from, e.g. in Chrome this is the IO thread. Must be called
  64   // after the thread is started. When called, this will attempt to start TPM
  65   // token loading.
  66   void SetCryptoTaskRunner(
  67       const scoped_refptr<base::SequencedTaskRunner>& crypto_task_runner);
  68
  69   // Starts loading TPM system token, if not yet started. It should be called
  70   // if the system token has to be loaded before a user logs in. By default (if
  71   // |EnsureStarted| is not called) system token loading will start when the
  72   // login state changes to LOGGED_IN_ACTIVE.
  73   void EnsureStarted();
  74
  75   // Checks if the TPM token is enabled. If the state is unknown, |callback|
  76   // will be called back once the TPM state is known.
  77   TPMTokenStatus IsTPMTokenEnabled(const TPMReadyCallback& callback);
  78
  79   std::string tpm_user_pin() const { return tpm_user_pin_; }
  80
  81  private:
  82   explicit TPMTokenLoader(bool for_test);
  83   ~TPMTokenLoader() override;
  84
  85   bool IsTPMLoadingEnabled() const;
  86
  87   // Starts tpm token initialization if the user is logged in and the crypto
  88   // task runner is set.
  89   void MaybeStartTokenInitialization();
  90
  91   // This is the cyclic chain of callbacks to initialize the TPM token.
  92   void ContinueTokenInitialization();
  93   void OnTPMTokenEnabledForNSS();
  94   void OnGotTpmTokenInfo(const TPMTokenInfo& token_info);
  95   void OnTPMTokenInitialized(bool success);
  96
  97   // Notifies observers that the TPM token is ready.
  98   void NotifyTPMTokenReady();
  99
 100   // LoginState::Observer
 101   void LoggedInStateChanged() override;
 102
 103   bool initialized_for_test_;
 104
 105   TPMReadyCallbackList tpm_ready_callback_list_;
 106
 107   // The states are traversed in this order but some might get omitted or never
 108   // be left.
 109   enum TPMTokenState {
 110     TPM_STATE_UNKNOWN,
 111     TPM_INITIALIZATION_STARTED,
 112     TPM_TOKEN_ENABLED_FOR_NSS,
 113     TPM_DISABLED,
 114     TPM_TOKEN_INFO_RECEIVED,
 115     TPM_TOKEN_INITIALIZED,
 116   };
 117   TPMTokenState tpm_token_state_;
 118
 119   scoped_ptr<TPMTokenInfoGetter> tpm_token_info_getter_;
 120
 121   // Cached TPM token info.
 122   int tpm_token_slot_id_;
 123   std::string tpm_user_pin_;
 124
 125   // Whether TPM system token loading may be started before user log in.
 126   // This will be true iff |EnsureStarted| was called.
 127   bool can_start_before_login_;
 128
 129   base::ThreadChecker thread_checker_;
 130
 131   // TaskRunner for crypto calls.
 132   scoped_refptr<base::SequencedTaskRunner> crypto_task_runner_;
 133
 134   base::WeakPtrFactory<TPMTokenLoader> weak_factory_;
 135
 136   DISALLOW_COPY_AND_ASSIGN(TPMTokenLoader);
 137 };
 138
 139 }  // namespace chromeos
 140
 141 #endif  // CHROMEOS_TPM_TPM_TOKEN_LOADER_H_