chromeos/tpm_token_info_getter.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_info_getter.h"
   6
   7 #include "base/bind.h"
   8 #include "base/location.h"
   9 #include "chromeos/dbus/cryptohome_client.h"
  10
  11 namespace {
  12
  13 const int64 kInitialRequestDelayMs = 100;
  14 const int64 kMaxRequestDelayMs = 300000;  // 5 minutes
  15
  16 // Calculates the delay before running next attempt to initiatialize the TPM
  17 // token, if |last_delay| was the last or initial delay.
  18 base::TimeDelta GetNextRequestDelayMs(base::TimeDelta last_delay) {
  19   // This implements an exponential backoff, as we don't know in which order of
  20   // magnitude the TPM token changes it's state.
  21   base::TimeDelta next_delay = last_delay * 2;
  22
  23   // Cap the delay to prevent an overflow. This threshold is arbitrarily chosen.
  24   const base::TimeDelta max_delay =
  25       base::TimeDelta::FromMilliseconds(kMaxRequestDelayMs);
  26   if (next_delay > max_delay)
  27     next_delay = max_delay;
  28   return next_delay;
  29 }
  30
  31 }  // namespace
  32
  33 namespace chromeos {
  34
  35 TPMTokenInfo::TPMTokenInfo()
  36     : tpm_is_enabled(false),
  37       token_slot_id(-1) {
  38 }
  39
  40 TPMTokenInfo::~TPMTokenInfo() {}
  41
  42 // static
  43 scoped_ptr<TPMTokenInfoGetter> TPMTokenInfoGetter::CreateForUserToken(
  44     const std::string& user_id,
  45     CryptohomeClient* cryptohome_client,
  46     const scoped_refptr<base::TaskRunner>& delayed_task_runner) {
  47   CHECK(!user_id.empty());
  48   return scoped_ptr<TPMTokenInfoGetter>(
  49       new TPMTokenInfoGetter(
  50           TYPE_USER, user_id, cryptohome_client, delayed_task_runner));
  51 }
  52
  53 // static
  54 scoped_ptr<TPMTokenInfoGetter> TPMTokenInfoGetter::CreateForSystemToken(
  55     CryptohomeClient* cryptohome_client,
  56     const scoped_refptr<base::TaskRunner>& delayed_task_runner) {
  57   return scoped_ptr<TPMTokenInfoGetter>(
  58       new TPMTokenInfoGetter(
  59           TYPE_SYSTEM, std::string(), cryptohome_client, delayed_task_runner));
  60 }
  61
  62 TPMTokenInfoGetter::~TPMTokenInfoGetter() {}
  63
  64 void TPMTokenInfoGetter::Start(const TPMTokenInfoCallback& callback) {
  65   CHECK(state_ == STATE_INITIAL);
  66   CHECK(!callback.is_null());
  67
  68   callback_ = callback;
  69
  70   state_ = STATE_STARTED;
  71   Continue();
  72 }
  73
  74 TPMTokenInfoGetter::TPMTokenInfoGetter(
  75     TPMTokenInfoGetter::Type type,
  76     const std::string& user_id,
  77     CryptohomeClient* cryptohome_client,
  78     const scoped_refptr<base::TaskRunner>& delayed_task_runner)
  79     : delayed_task_runner_(delayed_task_runner),
  80       type_(type),
  81       state_(TPMTokenInfoGetter::STATE_INITIAL),
  82       user_id_(user_id),
  83       tpm_request_delay_(
  84           base::TimeDelta::FromMilliseconds(kInitialRequestDelayMs)),
  85       cryptohome_client_(cryptohome_client),
  86       weak_factory_(this) {
  87 }
  88
  89 void TPMTokenInfoGetter::Continue() {
  90   switch (state_) {
  91     case STATE_INITIAL:
  92       NOTREACHED();
  93       break;
  94     case STATE_STARTED:
  95       cryptohome_client_->TpmIsEnabled(
  96           base::Bind(&TPMTokenInfoGetter::OnTpmIsEnabled,
  97                      weak_factory_.GetWeakPtr()));
  98       break;
  99     case STATE_TPM_ENABLED:
 100       if (type_ == TYPE_SYSTEM) {
 101         cryptohome_client_->Pkcs11GetTpmTokenInfo(
 102             base::Bind(&TPMTokenInfoGetter::OnPkcs11GetTpmTokenInfo,
 103                        weak_factory_.GetWeakPtr()));
 104       } else {  // if (type_ == TYPE_USER)
 105         cryptohome_client_->Pkcs11GetTpmTokenInfoForUser(
 106                 user_id_,
 107                 base::Bind(&TPMTokenInfoGetter::OnPkcs11GetTpmTokenInfo,
 108                            weak_factory_.GetWeakPtr()));
 109       }
 110       break;
 111     case STATE_DONE:
 112       NOTREACHED();
 113   }
 114 }
 115
 116 void TPMTokenInfoGetter::RetryLater() {
 117   delayed_task_runner_->PostDelayedTask(
 118       FROM_HERE,
 119       base::Bind(&TPMTokenInfoGetter::Continue, weak_factory_.GetWeakPtr()),
 120       tpm_request_delay_);
 121   tpm_request_delay_ = GetNextRequestDelayMs(tpm_request_delay_);
 122 }
 123
 124 void TPMTokenInfoGetter::OnTpmIsEnabled(DBusMethodCallStatus call_status,
 125                                         bool tpm_is_enabled) {
 126   if (call_status != DBUS_METHOD_CALL_SUCCESS) {
 127     RetryLater();
 128     return;
 129   }
 130
 131   if (!tpm_is_enabled) {
 132     state_ = STATE_DONE;
 133     callback_.Run(TPMTokenInfo());
 134     return;
 135   }
 136
 137   state_ = STATE_TPM_ENABLED;
 138   Continue();
 139 }
 140
 141 void TPMTokenInfoGetter::OnPkcs11GetTpmTokenInfo(
 142     DBusMethodCallStatus call_status,
 143     const std::string& token_name,
 144     const std::string& user_pin,
 145     int token_slot_id) {
 146   if (call_status == DBUS_METHOD_CALL_FAILURE || token_slot_id == -1) {
 147     RetryLater();
 148     return;
 149   }
 150
 151   state_ = STATE_DONE;
 152
 153   TPMTokenInfo token_info;
 154   token_info.tpm_is_enabled = true;
 155   token_info.token_name = token_name;
 156   token_info.user_pin = user_pin;
 157   token_info.token_slot_id = token_slot_id;
 158
 159   callback_.Run(token_info);
 160 }
 161
 162 }  // namespace chromeos