src/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 TPMTokenLoader::TPMTokenStatus TPMTokenLoader::IsTPMTokenEnabled(
 110     const TPMReadyCallback& callback) {
 111   if (tpm_token_state_ == TPM_TOKEN_INITIALIZED)
 112     return TPM_TOKEN_STATUS_ENABLED;
 113   if (!IsTPMLoadingEnabled() || tpm_token_state_ == TPM_DISABLED)
 114     return TPM_TOKEN_STATUS_DISABLED;
 115   // Status is not known yet.
 116   if (!callback.is_null())
 117     tpm_ready_callback_list_.push_back(callback);
 118   return TPM_TOKEN_STATUS_UNDETERMINED;
 119 }
 120
 121 bool TPMTokenLoader::IsTPMLoadingEnabled() const {
 122   // TPM loading is enabled on non-ChromeOS environments, e.g. when running
 123   // tests on Linux.
 124   // Treat TPM as disabled for guest users since they do not store certs.
 125   return initialized_for_test_ || (base::SysInfo::IsRunningOnChromeOS() &&
 126                                    !LoginState::Get()->IsGuestSessionUser());
 127 }
 128
 129 void TPMTokenLoader::MaybeStartTokenInitialization() {
 130   CHECK(thread_checker_.CalledOnValidThread());
 131
 132   // This is the entry point to the TPM token initialization process,
 133   // which we should do at most once.
 134   if (tpm_token_state_ != TPM_STATE_UNKNOWN || !crypto_task_runner_.get())
 135     return;
 136
 137   if (!LoginState::IsInitialized())
 138     return;
 139
 140   bool start_initialization = LoginState::Get()->IsUserLoggedIn();
 141
 142   VLOG(1) << "StartTokenInitialization: " << start_initialization;
 143   if (!start_initialization)
 144     return;
 145
 146   if (!IsTPMLoadingEnabled())
 147     tpm_token_state_ = TPM_DISABLED;
 148
 149   ContinueTokenInitialization();
 150
 151   DCHECK_NE(tpm_token_state_, TPM_STATE_UNKNOWN);
 152 }
 153
 154 void TPMTokenLoader::ContinueTokenInitialization() {
 155   CHECK(thread_checker_.CalledOnValidThread());
 156   VLOG(1) << "ContinueTokenInitialization: " << tpm_token_state_;
 157
 158   switch (tpm_token_state_) {
 159     case TPM_STATE_UNKNOWN: {
 160       crypto_task_runner_->PostTaskAndReply(
 161           FROM_HERE,
 162           base::Bind(&crypto::EnableTPMTokenForNSS),
 163           base::Bind(&TPMTokenLoader::OnTPMTokenEnabledForNSS,
 164                      weak_factory_.GetWeakPtr()));
 165       tpm_token_state_ = TPM_INITIALIZATION_STARTED;
 166       return;
 167     }
 168     case TPM_INITIALIZATION_STARTED: {
 169       NOTREACHED();
 170       return;
 171     }
 172     case TPM_TOKEN_ENABLED_FOR_NSS: {
 173       DBusThreadManager::Get()->GetCryptohomeClient()->TpmIsEnabled(
 174           base::Bind(&TPMTokenLoader::OnTpmIsEnabled,
 175                      weak_factory_.GetWeakPtr()));
 176       return;
 177     }
 178     case TPM_DISABLED: {
 179       // TPM is disabled, so proceed with empty tpm token name.
 180       NotifyTPMTokenReady();
 181       return;
 182     }
 183     case TPM_ENABLED: {
 184       DBusThreadManager::Get()->GetCryptohomeClient()->Pkcs11IsTpmTokenReady(
 185           base::Bind(&TPMTokenLoader::OnPkcs11IsTpmTokenReady,
 186                      weak_factory_.GetWeakPtr()));
 187       return;
 188     }
 189     case TPM_TOKEN_READY: {
 190       // Retrieve user_pin_ here since they will never change
 191       // and CryptohomeClient calls are not thread safe.
 192       DBusThreadManager::Get()->GetCryptohomeClient()->Pkcs11GetTpmTokenInfo(
 193           base::Bind(&TPMTokenLoader::OnPkcs11GetTpmTokenInfo,
 194                      weak_factory_.GetWeakPtr()));
 195       return;
 196     }
 197     case TPM_TOKEN_INFO_RECEIVED: {
 198       crypto_task_runner_->PostTask(
 199           FROM_HERE,
 200           base::Bind(
 201               &crypto::InitializeTPMTokenAndSystemSlot,
 202               tpm_token_slot_id_,
 203               base::Bind(&PostResultToTaskRunner,
 204                          base::MessageLoopProxy::current(),
 205                          base::Bind(&TPMTokenLoader::OnTPMTokenInitialized,
 206                                     weak_factory_.GetWeakPtr()))));
 207       return;
 208     }
 209     case TPM_TOKEN_INITIALIZED: {
 210       NotifyTPMTokenReady();
 211       return;
 212     }
 213   }
 214 }
 215
 216 void TPMTokenLoader::RetryTokenInitializationLater() {
 217   CHECK(thread_checker_.CalledOnValidThread());
 218   VLOG(1) << "Retry token initialization later.";
 219   base::MessageLoopProxy::current()->PostDelayedTask(
 220       FROM_HERE,
 221       base::Bind(&TPMTokenLoader::ContinueTokenInitialization,
 222                  weak_factory_.GetWeakPtr()),
 223       tpm_request_delay_);
 224   tpm_request_delay_ = GetNextRequestDelayMs(tpm_request_delay_);
 225 }
 226
 227 void TPMTokenLoader::OnTPMTokenEnabledForNSS() {
 228   VLOG(1) << "TPMTokenEnabledForNSS";
 229   tpm_token_state_ = TPM_TOKEN_ENABLED_FOR_NSS;
 230   ContinueTokenInitialization();
 231 }
 232
 233 void TPMTokenLoader::OnTpmIsEnabled(DBusMethodCallStatus call_status,
 234                                     bool tpm_is_enabled) {
 235   VLOG(1) << "OnTpmIsEnabled: " << tpm_is_enabled;
 236
 237   if (call_status == DBUS_METHOD_CALL_SUCCESS && tpm_is_enabled)
 238     tpm_token_state_ = TPM_ENABLED;
 239   else
 240     tpm_token_state_ = TPM_DISABLED;
 241
 242   ContinueTokenInitialization();
 243 }
 244
 245 void TPMTokenLoader::OnPkcs11IsTpmTokenReady(DBusMethodCallStatus call_status,
 246                                              bool is_tpm_token_ready) {
 247   VLOG(1) << "OnPkcs11IsTpmTokenReady: " << is_tpm_token_ready;
 248
 249   if (call_status == DBUS_METHOD_CALL_FAILURE || !is_tpm_token_ready) {
 250     RetryTokenInitializationLater();
 251     return;
 252   }
 253
 254   tpm_token_state_ = TPM_TOKEN_READY;
 255   ContinueTokenInitialization();
 256 }
 257
 258 void TPMTokenLoader::OnPkcs11GetTpmTokenInfo(DBusMethodCallStatus call_status,
 259                                              const std::string& token_name,
 260                                              const std::string& user_pin,
 261                                              int token_slot_id) {
 262   VLOG(1) << "OnPkcs11GetTpmTokenInfo: " << token_name;
 263
 264   if (call_status == DBUS_METHOD_CALL_FAILURE) {
 265     RetryTokenInitializationLater();
 266     return;
 267   }
 268
 269   tpm_token_slot_id_ = token_slot_id;
 270   tpm_user_pin_ = user_pin;
 271   tpm_token_state_ = TPM_TOKEN_INFO_RECEIVED;
 272
 273   ContinueTokenInitialization();
 274 }
 275
 276 void TPMTokenLoader::OnTPMTokenInitialized(bool success) {
 277   VLOG(1) << "OnTPMTokenInitialized: " << success;
 278   if (!success) {
 279     RetryTokenInitializationLater();
 280     return;
 281   }
 282   tpm_token_state_ = TPM_TOKEN_INITIALIZED;
 283   ContinueTokenInitialization();
 284 }
 285
 286 void TPMTokenLoader::NotifyTPMTokenReady() {
 287   DCHECK(tpm_token_state_ == TPM_DISABLED ||
 288          tpm_token_state_ == TPM_TOKEN_INITIALIZED);
 289   bool tpm_status = tpm_token_state_ == TPM_TOKEN_INITIALIZED;
 290   for (TPMReadyCallbackList::iterator i = tpm_ready_callback_list_.begin();
 291        i != tpm_ready_callback_list_.end();
 292        ++i) {
 293     i->Run(tpm_status);
 294   }
 295   tpm_ready_callback_list_.clear();
 296 }
 297
 298 void TPMTokenLoader::LoggedInStateChanged() {
 299   VLOG(1) << "LoggedInStateChanged";
 300   MaybeStartTokenInitialization();
 301 }
 302
 303 }  // namespace chromeos