chromeos/tpm_token_loader.cc

   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 #include "chromeos/tpm_token_loader.h"
   6
   7 #include <algorithm>
   8
   9 #include "base/bind.h"
  10 #include "base/location.h"
  11 #include "base/message_loop/message_loop_proxy.h"
  12 #include "base/sequenced_task_runner.h"
  13 #include "base/sys_info.h"
  14 #include "base/task_runner_util.h"
  15 #include "chromeos/dbus/cryptohome_client.h"
  16 #include "chromeos/dbus/dbus_thread_manager.h"
  17 #include "crypto/nss_util.h"
  18
  19 namespace chromeos {
  20
  21 namespace {
  22
  23 const int64 kInitialRequestDelayMs = 100;
  24 const int64 kMaxRequestDelayMs = 300000;  // 5 minutes
  25
  26 // Calculates the delay before running next attempt to initiatialize the TPM
  27 // token, if |last_delay| was the last or initial delay.
  28 base::TimeDelta GetNextRequestDelayMs(base::TimeDelta last_delay) {
  29   // This implements an exponential backoff, as we don't know in which order of
  30   // magnitude the TPM token changes it's state.
  31   base::TimeDelta next_delay = last_delay * 2;
  32
  33   // Cap the delay to prevent an overflow. This threshold is arbitrarily chosen.
  34   const base::TimeDelta max_delay =
  35       base::TimeDelta::FromMilliseconds(kMaxRequestDelayMs);
  36   if (next_delay > max_delay)
  37     next_delay = max_delay;
  38   return next_delay;
  39 }
  40
  41 void PostResultToTaskRunner(scoped_refptr<base::SequencedTaskRunner> runner,
  42                             const base::Callback<void(bool)>& callback,
  43                             bool success) {
  44   runner->PostTask(FROM_HERE, base::Bind(callback, success));
  45 }
  46
  47 }  // namespace
  48
  49 static TPMTokenLoader* g_tpm_token_loader = NULL;
  50
  51 // static
  52 void TPMTokenLoader::Initialize() {
  53   CHECK(!g_tpm_token_loader);
  54   g_tpm_token_loader = new TPMTokenLoader(false /*for_test*/);
  55 }
  56
  57 // static
  58 void TPMTokenLoader::InitializeForTest() {
  59   CHECK(!g_tpm_token_loader);
  60   g_tpm_token_loader = new TPMTokenLoader(true /*for_test*/);
  61 }
  62
  63 // static
  64 void TPMTokenLoader::Shutdown() {
  65   CHECK(g_tpm_token_loader);
  66   delete g_tpm_token_loader;
  67   g_tpm_token_loader = NULL;
  68 }
  69
  70 // static
  71 TPMTokenLoader* TPMTokenLoader::Get() {
  72   CHECK(g_tpm_token_loader)
  73       << "TPMTokenLoader::Get() called before Initialize()";
  74   return g_tpm_token_loader;
  75 }
  76
  77 // static
  78 bool TPMTokenLoader::IsInitialized() {
  79   return g_tpm_token_loader;
  80 }
  81
  82 TPMTokenLoader::TPMTokenLoader(bool for_test)
  83     : initialized_for_test_(for_test),
  84       tpm_token_state_(TPM_STATE_UNKNOWN),
  85       tpm_request_delay_(
  86           base::TimeDelta::FromMilliseconds(kInitialRequestDelayMs)),
  87       tpm_token_slot_id_(-1),
  88       weak_factory_(this) {
  89   if (!initialized_for_test_ && LoginState::IsInitialized())
  90     LoginState::Get()->AddObserver(this);
  91
  92   if (initialized_for_test_) {
  93     tpm_token_state_ = TPM_TOKEN_INITIALIZED;
  94     tpm_user_pin_ = "111111";
  95   }
  96 }
  97
  98 void TPMTokenLoader::SetCryptoTaskRunner(
  99     const scoped_refptr<base::SequencedTaskRunner>& crypto_task_runner) {
 100   crypto_task_runner_ = crypto_task_runner;
 101   MaybeStartTokenInitialization();
 102 }
 103
 104 TPMTokenLoader::~TPMTokenLoader() {
 105   if (!initialized_for_test_ && LoginState::IsInitialized())
 106     LoginState::Get()->RemoveObserver(this);
 107 }
 108
 109 void TPMTokenLoader::AddObserver(TPMTokenLoader::Observer* observer) {
 110   observers_.AddObserver(observer);
 111 }
 112
 113 void TPMTokenLoader::RemoveObserver(TPMTokenLoader::Observer* observer) {
 114   observers_.RemoveObserver(observer);
 115 }
 116
 117 bool TPMTokenLoader::IsTPMTokenReady() const {
 118   return tpm_token_state_ == TPM_DISABLED ||
 119          tpm_token_state_ == TPM_TOKEN_INITIALIZED;
 120 }
 121
 122 void TPMTokenLoader::MaybeStartTokenInitialization() {
 123   CHECK(thread_checker_.CalledOnValidThread());
 124
 125   // This is the entry point to the TPM token initialization process,
 126   // which we should do at most once.
 127   if (tpm_token_state_ != TPM_STATE_UNKNOWN || !crypto_task_runner_.get())
 128     return;
 129
 130   if (!LoginState::IsInitialized())
 131     return;
 132
 133   bool start_initialization = LoginState::Get()->IsUserLoggedIn();
 134
 135   VLOG(1) << "StartTokenInitialization: " << start_initialization;
 136   if (!start_initialization)
 137     return;
 138
 139   if (!base::SysInfo::IsRunningOnChromeOS())
 140     tpm_token_state_ = TPM_DISABLED;
 141
 142   // Treat TPM as disabled for guest users since they do not store certs.
 143   if (LoginState::Get()->IsGuestSessionUser())
 144     tpm_token_state_ = TPM_DISABLED;
 145
 146   ContinueTokenInitialization();
 147
 148   DCHECK_NE(tpm_token_state_, TPM_STATE_UNKNOWN);
 149 }
 150
 151 void TPMTokenLoader::ContinueTokenInitialization() {
 152   CHECK(thread_checker_.CalledOnValidThread());
 153   VLOG(1) << "ContinueTokenInitialization: " << tpm_token_state_;
 154
 155   switch (tpm_token_state_) {
 156     case TPM_STATE_UNKNOWN: {
 157       crypto_task_runner_->PostTaskAndReply(
 158           FROM_HERE,
 159           base::Bind(&crypto::EnableTPMTokenForNSS),
 160           base::Bind(&TPMTokenLoader::OnTPMTokenEnabledForNSS,
 161                      weak_factory_.GetWeakPtr()));
 162       tpm_token_state_ = TPM_INITIALIZATION_STARTED;
 163       return;
 164     }
 165     case TPM_INITIALIZATION_STARTED: {
 166       NOTREACHED();
 167       return;
 168     }
 169     case TPM_TOKEN_ENABLED_FOR_NSS: {
 170       DBusThreadManager::Get()->GetCryptohomeClient()->TpmIsEnabled(
 171           base::Bind(&TPMTokenLoader::OnTpmIsEnabled,
 172                      weak_factory_.GetWeakPtr()));
 173       return;
 174     }
 175     case TPM_DISABLED: {
 176       // TPM is disabled, so proceed with empty tpm token name.
 177       NotifyTPMTokenReady();
 178       return;
 179     }
 180     case TPM_ENABLED: {
 181       DBusThreadManager::Get()->GetCryptohomeClient()->Pkcs11IsTpmTokenReady(
 182           base::Bind(&TPMTokenLoader::OnPkcs11IsTpmTokenReady,
 183                      weak_factory_.GetWeakPtr()));
 184       return;
 185     }
 186     case TPM_TOKEN_READY: {
 187       // Retrieve user_pin_ here since they will never change
 188       // and CryptohomeClient calls are not thread safe.
 189       DBusThreadManager::Get()->GetCryptohomeClient()->Pkcs11GetTpmTokenInfo(
 190           base::Bind(&TPMTokenLoader::OnPkcs11GetTpmTokenInfo,
 191                      weak_factory_.GetWeakPtr()));
 192       return;
 193     }
 194     case TPM_TOKEN_INFO_RECEIVED: {
 195       crypto_task_runner_->PostTask(
 196           FROM_HERE,
 197           base::Bind(
 198               &crypto::InitializeTPMTokenAndSystemSlot,
 199               tpm_token_slot_id_,
 200               base::Bind(&PostResultToTaskRunner,
 201                          base::MessageLoopProxy::current(),
 202                          base::Bind(&TPMTokenLoader::OnTPMTokenInitialized,
 203                                     weak_factory_.GetWeakPtr()))));
 204       return;
 205     }
 206     case TPM_TOKEN_INITIALIZED: {
 207       NotifyTPMTokenReady();
 208       return;
 209     }
 210   }
 211 }
 212
 213 void TPMTokenLoader::RetryTokenInitializationLater() {
 214   CHECK(thread_checker_.CalledOnValidThread());
 215   VLOG(1) << "Retry token initialization later.";
 216   base::MessageLoopProxy::current()->PostDelayedTask(
 217       FROM_HERE,
 218       base::Bind(&TPMTokenLoader::ContinueTokenInitialization,
 219                  weak_factory_.GetWeakPtr()),
 220       tpm_request_delay_);
 221   tpm_request_delay_ = GetNextRequestDelayMs(tpm_request_delay_);
 222 }
 223
 224 void TPMTokenLoader::OnTPMTokenEnabledForNSS() {
 225   VLOG(1) << "TPMTokenEnabledForNSS";
 226   tpm_token_state_ = TPM_TOKEN_ENABLED_FOR_NSS;
 227   ContinueTokenInitialization();
 228 }
 229
 230 void TPMTokenLoader::OnTpmIsEnabled(DBusMethodCallStatus call_status,
 231                                     bool tpm_is_enabled) {
 232   VLOG(1) << "OnTpmIsEnabled: " << tpm_is_enabled;
 233
 234   if (call_status == DBUS_METHOD_CALL_SUCCESS && tpm_is_enabled)
 235     tpm_token_state_ = TPM_ENABLED;
 236   else
 237     tpm_token_state_ = TPM_DISABLED;
 238
 239   ContinueTokenInitialization();
 240 }
 241
 242 void TPMTokenLoader::OnPkcs11IsTpmTokenReady(DBusMethodCallStatus call_status,
 243                                          bool is_tpm_token_ready) {
 244   VLOG(1) << "OnPkcs11IsTpmTokenReady: " << is_tpm_token_ready;
 245
 246   if (call_status == DBUS_METHOD_CALL_FAILURE || !is_tpm_token_ready) {
 247     RetryTokenInitializationLater();
 248     return;
 249   }
 250
 251   tpm_token_state_ = TPM_TOKEN_READY;
 252   ContinueTokenInitialization();
 253 }
 254
 255 void TPMTokenLoader::OnPkcs11GetTpmTokenInfo(DBusMethodCallStatus call_status,
 256                                              const std::string& token_name,
 257                                              const std::string& user_pin,
 258                                              int token_slot_id) {
 259   VLOG(1) << "OnPkcs11GetTpmTokenInfo: " << token_name;
 260
 261   if (call_status == DBUS_METHOD_CALL_FAILURE) {
 262     RetryTokenInitializationLater();
 263     return;
 264   }
 265
 266   tpm_token_slot_id_ = token_slot_id;
 267   tpm_user_pin_ = user_pin;
 268   tpm_token_state_ = TPM_TOKEN_INFO_RECEIVED;
 269
 270   ContinueTokenInitialization();
 271 }
 272
 273 void TPMTokenLoader::OnTPMTokenInitialized(bool success) {
 274   VLOG(1) << "OnTPMTokenInitialized: " << success;
 275   if (!success) {
 276     RetryTokenInitializationLater();
 277     return;
 278   }
 279   tpm_token_state_ = TPM_TOKEN_INITIALIZED;
 280   ContinueTokenInitialization();
 281 }
 282
 283 void TPMTokenLoader::NotifyTPMTokenReady() {
 284   FOR_EACH_OBSERVER(Observer, observers_, OnTPMTokenReady());
 285 }
 286
 287 void TPMTokenLoader::LoggedInStateChanged() {
 288   VLOG(1) << "LoggedInStateChanged";
 289   MaybeStartTokenInitialization();
 290 }
 291
 292 }  // namespace chromeos