cryptohome/tpm2_impl.cc

// Copyright 2015 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Contains the implementation of class Tpm

#include "cryptohome/tpm2_impl.h"

#include <memory>
#include <string>

#include <base/logging.h>
#include <base/memory/ptr_util.h>
#include <brillo/bind_lambda.h>
#include <crypto/scoped_openssl_types.h>
#include <openssl/rsa.h>
#include <trunks/authorization_delegate.h>
#include <trunks/blob_parser.h>
#include <trunks/error_codes.h>
#include <trunks/policy_session.h>
#include <trunks/tpm_constants.h>
#include <trunks/tpm_generated.h>
#include <trunks/trunks_factory.h>
#include <trunks/trunks_factory_impl.h>
#include <trunks/trunks_dbus_proxy.h>

#include "cryptohome/cryptolib.h"

using brillo::SecureBlob;
using trunks::GetErrorString;
using trunks::TPM_RC;
using trunks::TPM_RC_SUCCESS;
using trunks::TrunksFactory;

namespace cryptohome {

Tpm2Impl::Tpm2Impl(TrunksFactory* factory,
                   tpm_manager::TpmOwnershipInterface* tpm_owner,
                   tpm_manager::TpmNvramInterface* tpm_nvram)
    : has_external_trunks_context_(true),
      tpm_owner_(tpm_owner),
      tpm_nvram_(tpm_nvram) {
  external_trunks_context_.factory = factory;
  external_trunks_context_.tpm_state = factory->GetTpmState();
  external_trunks_context_.tpm_utility = factory->GetTpmUtility();
}

bool Tpm2Impl::GetOwnerPassword(brillo::Blob* owner_password) {
  if (!UpdateTpmStatus(RefreshType::REFRESH_IF_NEEDED)) {
    return false;
  }
  SecureBlob tmp(tpm_status_.local_data().owner_password());
  owner_password->swap(tmp);
  return true;
}

void Tpm2Impl::SetOwnerPassword(const SecureBlob& /* owner_password */) {
  LOG(ERROR) << __func__ << ": Not Implemented.";
}

bool Tpm2Impl::IsEnabled() {
  if (!UpdateTpmStatus(RefreshType::REFRESH_IF_NEEDED)) {
    return false;
  }
  return tpm_status_.enabled();
}

void Tpm2Impl::SetIsEnabled(bool /* enabled */) {
  LOG(ERROR) << __func__ << ": Not Implemented.";
}

bool Tpm2Impl::IsOwned() {
  if (!UpdateTpmStatus(RefreshType::REFRESH_IF_NEEDED)) {
    return false;
  }
  return tpm_status_.owned();
}

void Tpm2Impl::SetIsOwned(bool /* owned */) {
  LOG(ERROR) << __func__ << ": Not Implemented.";
}

bool Tpm2Impl::PerformEnabledOwnedCheck(bool* enabled, bool* owned) {
  if (!UpdateTpmStatus(RefreshType::REFRESH_IF_NEEDED)) {
    return false;
  }
  if (enabled) {
    *enabled = tpm_status_.enabled();
  }
  if (owned) {
    *owned = tpm_status_.owned();
  }
  return true;
}

bool Tpm2Impl::IsInitialized() {
  return UpdateTpmStatus(RefreshType::REFRESH_IF_NEEDED);
}

void Tpm2Impl::SetIsInitialized(bool done) {
  LOG(ERROR) << __func__ << ": Not Implemented.";
}

bool Tpm2Impl::IsBeingOwned() {
  LOG(ERROR) << __func__ << ": Not Implemented.";
  return false;
}

void Tpm2Impl::SetIsBeingOwned(bool /* value */) {
  LOG(ERROR) << __func__ << ": Not Implemented.";
}

bool Tpm2Impl::GetRandomData(size_t length, brillo::Blob* data) {
  CHECK(data);
  TrunksClientContext* trunks;
  if (!GetTrunksContext(&trunks)) {
    return false;
  }
  std::string random_data;
  TPM_RC result =
      trunks->tpm_utility->GenerateRandom(length,
                                          nullptr,  // No authorization.
                                          &random_data);
  if ((result != TPM_RC_SUCCESS) || (random_data.size() != length)) {
    LOG(ERROR) << "Error getting random data: " << GetErrorString(result);
    return false;
  }
  data->assign(random_data.begin(), random_data.end());
  return true;
}

bool Tpm2Impl::DefineNvram(uint32_t index, size_t length, uint32_t flags) {
  if (!InitializeTpmManagerClients()) {
    return false;
  }
  tpm_manager::DefineSpaceRequest request;
  request.set_index(index);
  request.set_size(length);
  if (flags & Tpm::kTpmNvramWriteDefine) {
    request.add_attributes(tpm_manager::NVRAM_PERSISTENT_WRITE_LOCK);
  }
  if (flags & Tpm::kTpmNvramBindToPCR0) {
    request.set_policy(tpm_manager::NVRAM_POLICY_PCR0);
  }
  auto method = base::Bind(&tpm_manager::TpmNvramInterface::DefineSpace,
                           base::Unretained(tpm_nvram_), request);
  tpm_manager::DefineSpaceReply reply;
  SendTpmManagerRequestAndWait(method, &reply);
  if (reply.result() != tpm_manager::NVRAM_RESULT_SUCCESS) {
    LOG(ERROR) << "Failed to define nvram space: " << reply.result();
    return false;
  }
  return true;
}

bool Tpm2Impl::DestroyNvram(uint32_t index) {
  if (!InitializeTpmManagerClients()) {
    return false;
  }
  tpm_manager::DestroySpaceRequest request;
  request.set_index(index);
  auto method = base::Bind(&tpm_manager::TpmNvramInterface::DestroySpace,
                           base::Unretained(tpm_nvram_), request);
  tpm_manager::DestroySpaceReply reply;
  SendTpmManagerRequestAndWait(method, &reply);
  if (reply.result() != tpm_manager::NVRAM_RESULT_SUCCESS) {
    LOG(ERROR) << "Failed to destroy nvram space: " << reply.result();
    return false;
  }
  return true;
}

bool Tpm2Impl::WriteNvram(uint32_t index, const SecureBlob& blob) {
  if (!InitializeTpmManagerClients()) {
    return false;
  }
  tpm_manager::WriteSpaceRequest write_request;
  write_request.set_index(index);
  write_request.set_data(blob.to_string());
  auto write_method = base::Bind(&tpm_manager::TpmNvramInterface::WriteSpace,
                                 base::Unretained(tpm_nvram_), write_request);
  tpm_manager::WriteSpaceReply write_reply;
  SendTpmManagerRequestAndWait(write_method, &write_reply);
  if (write_reply.result() != tpm_manager::NVRAM_RESULT_SUCCESS) {
    LOG(ERROR) << "Failed to write nvram space: " << write_reply.result();
    return false;
  }
  tpm_manager::LockSpaceRequest lock_request;
  lock_request.set_index(index);
  lock_request.set_lock_write(true);
  auto lock_method = base::Bind(&tpm_manager::TpmNvramInterface::LockSpace,
                                base::Unretained(tpm_nvram_), lock_request);
  tpm_manager::LockSpaceReply lock_reply;
  SendTpmManagerRequestAndWait(lock_method, &lock_reply);
  if (lock_reply.result() != tpm_manager::NVRAM_RESULT_SUCCESS) {
    LOG(ERROR) << "Failed to lock nvram space: " << lock_reply.result();
    return false;
  }
  return true;
}

bool Tpm2Impl::ReadNvram(uint32_t index, SecureBlob* blob) {
  if (!InitializeTpmManagerClients()) {
    return false;
  }
  tpm_manager::ReadSpaceRequest request;
  request.set_index(index);
  auto method = base::Bind(&tpm_manager::TpmNvramInterface::ReadSpace,
                           base::Unretained(tpm_nvram_), request);
  tpm_manager::ReadSpaceReply reply;
  SendTpmManagerRequestAndWait(method, &reply);
  if (reply.result() != tpm_manager::NVRAM_RESULT_SUCCESS) {
    LOG(ERROR) << "Failed to read nvram space: " << reply.result();
    return false;
  }
  SecureBlob tmp(reply.data());
  blob->swap(tmp);
  return true;
}

bool Tpm2Impl::IsNvramDefined(uint32_t index) {
  if (!InitializeTpmManagerClients()) {
    return false;
  }
  auto method = base::Bind(&tpm_manager::TpmNvramInterface::ListSpaces,
                           base::Unretained(tpm_nvram_),
                           tpm_manager::ListSpacesRequest());
  tpm_manager::ListSpacesReply reply;
  SendTpmManagerRequestAndWait(method, &reply);
  if (reply.result() != tpm_manager::NVRAM_RESULT_SUCCESS) {
    LOG(ERROR) << "Failed to list nvram spaces: " << reply.result();
    return false;
  }
  for (int i = 0; i < reply.index_list_size(); ++i) {
    if (index == reply.index_list(i)) {
      return true;
    }
  }
  return false;
}

bool Tpm2Impl::IsNvramLocked(uint32_t index) {
  if (!InitializeTpmManagerClients()) {
    return false;
  }
  tpm_manager::GetSpaceInfoRequest request;
  request.set_index(index);
  auto method = base::Bind(&tpm_manager::TpmNvramInterface::GetSpaceInfo,
                           base::Unretained(tpm_nvram_), request);
  tpm_manager::GetSpaceInfoReply reply;
  SendTpmManagerRequestAndWait(method, &reply);
  if (reply.result() != tpm_manager::NVRAM_RESULT_SUCCESS) {
    LOG(ERROR) << "Failed to get space info for space " << index << ": "
               << reply.result();
    return false;
  }
  return reply.is_write_locked();
}

unsigned int Tpm2Impl::GetNvramSize(uint32_t index) {
  if (!InitializeTpmManagerClients()) {
    return false;
  }
  tpm_manager::GetSpaceInfoRequest request;
  request.set_index(index);
  auto method = base::Bind(&tpm_manager::TpmNvramInterface::GetSpaceInfo,
                           base::Unretained(tpm_nvram_), request);
  tpm_manager::GetSpaceInfoReply reply;
  SendTpmManagerRequestAndWait(method, &reply);
  if (reply.result() != tpm_manager::NVRAM_RESULT_SUCCESS) {
    LOG(ERROR) << "Failed to get space info for space " << index << ": "
               << reply.result();
    return 0;
  }
  return reply.size();
}

bool Tpm2Impl::IsEndorsementKeyAvailable() {
  LOG(ERROR) << __func__ << ": Not Implemented.";
  return true;
}

bool Tpm2Impl::CreateEndorsementKey() {
  LOG(ERROR) << __func__ << ": Not Implemented.";
  return false;
}

bool Tpm2Impl::GetEndorsementPublicKey(SecureBlob* ek_public_key) {
  LOG(ERROR) << __func__ << ": Not Implemented.";
  return false;
}

bool Tpm2Impl::GetEndorsementCredential(SecureBlob* credential) {
  LOG(ERROR) << __func__ << ": Not Implemented.";
  return false;
}

bool Tpm2Impl::MakeIdentity(SecureBlob* identity_public_key_der,
                            SecureBlob* identity_public_key,
                            SecureBlob* identity_key_blob,
                            SecureBlob* identity_binding,
                            SecureBlob* identity_label,
                            SecureBlob* pca_public_key,
                            SecureBlob* endorsement_credential,
                            SecureBlob* platform_credential,
                            SecureBlob* conformance_credential) {
  LOG(ERROR) << __func__ << ": Not Implemented.";
  return false;
}

bool Tpm2Impl::QuotePCR(int pcr_index,
                        const SecureBlob& identity_key_blob,
                        const SecureBlob& external_data,
                        SecureBlob* pcr_value,
                        SecureBlob* quoted_data,
                        SecureBlob* quote) {
  LOG(ERROR) << __func__ << ": Not Implemented.";
  return false;
}

bool Tpm2Impl::SealToPCR0(const brillo::Blob& value,
                          brillo::Blob* sealed_value) {
  TrunksClientContext* trunks;
  if (!GetTrunksContext(&trunks)) {
    return false;
  }
  std::string policy_digest;
  TPM_RC result =
      trunks->tpm_utility->GetPolicyDigestForPcrValue(0, "", &policy_digest);
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error getting policy digest: " << GetErrorString(result);
    return false;
  }
  std::unique_ptr<trunks::HmacSession> session =
      trunks->factory->GetHmacSession();
  if (trunks->tpm_utility->StartSession(session.get()) != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error starting hmac session.";
    return false;
  }
  std::string data_to_seal(value.begin(), value.end());
  std::string sealed_data;
  result = trunks->tpm_utility->SealData(data_to_seal, policy_digest,
                                         session->GetDelegate(), &sealed_data);
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error creating sealed object: " << GetErrorString(result);
    return false;
  }
  sealed_value->assign(sealed_data.begin(), sealed_data.end());
  return true;
}

bool Tpm2Impl::Unseal(const brillo::Blob& sealed_value, brillo::Blob* value) {
  TrunksClientContext* trunks;
  if (!GetTrunksContext(&trunks)) {
    return false;
  }
  std::unique_ptr<trunks::PolicySession> policy_session =
      trunks->factory->GetPolicySession();
  TPM_RC result = policy_session->StartUnboundSession(false);
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error starting policy session: " << GetErrorString(result);
    return false;
  }
  result = policy_session->PolicyPCR(0, "");
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error restricting policy to pcr 0: "
               << GetErrorString(result);
    return false;
  }
  std::string sealed_data(sealed_value.begin(), sealed_value.end());
  std::string unsealed_data;
  result = trunks->tpm_utility->UnsealData(
      sealed_data, policy_session->GetDelegate(), &unsealed_data);
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error unsealing object: " << GetErrorString(result);
    return false;
  }
  value->assign(unsealed_data.begin(), unsealed_data.end());
  return true;
}

bool Tpm2Impl::CreateCertifiedKey(const SecureBlob& identity_key_blob,
                                  const SecureBlob& external_data,
                                  SecureBlob* certified_public_key,
                                  SecureBlob* certified_public_key_der,
                                  SecureBlob* certified_key_blob,
                                  SecureBlob* certified_key_info,
                                  SecureBlob* certified_key_proof) {
  LOG(ERROR) << __func__ << ": Not Implemented.";
  return false;
}

bool Tpm2Impl::CreateDelegate(const SecureBlob& identity_key_blob,
                              SecureBlob* delegate_blob,
                              SecureBlob* delegate_secret) {
  LOG(ERROR) << __func__ << ": Not Implemented.";
  return false;
}

bool Tpm2Impl::ActivateIdentity(const SecureBlob& delegate_blob,
                                const SecureBlob& delegate_secret,
                                const SecureBlob& identity_key_blob,
                                const SecureBlob& encrypted_asym_ca,
                                const SecureBlob& encrypted_sym_ca,
                                SecureBlob* identity_credential) {
  LOG(ERROR) << __func__ << ": Not Implemented.";
  return false;
}

bool Tpm2Impl::TakeOwnership(int max_timeout_tries,
                             const SecureBlob& owner_password) {
  if (!InitializeTpmManagerClients()) {
    return false;
  }
  auto method = base::Bind(&tpm_manager::TpmOwnershipInterface::TakeOwnership,
                           base::Unretained(tpm_owner_),
                           tpm_manager::TakeOwnershipRequest());
  tpm_manager::TakeOwnershipReply reply;
  SendTpmManagerRequestAndWait(method, &reply);
  return (reply.status() == tpm_manager::STATUS_SUCCESS);
}

bool Tpm2Impl::InitializeSrk(const SecureBlob& owner_password) {
  // Not necessary, tpm_managerd takes care of all this.
  LOG(WARNING) << __func__ << ": Not Implemented.";
  return true;
}

bool Tpm2Impl::ChangeOwnerPassword(const SecureBlob& previous_owner_password,
                                   const SecureBlob& owner_password) {
  LOG(ERROR) << __func__ << ": Not Implemented.";
  return false;
}

bool Tpm2Impl::TestTpmAuth(const SecureBlob& owner_password) {
  LOG(ERROR) << __func__ << ": Not Implemented.";
  return false;
}

bool Tpm2Impl::IsTransient(TpmRetryAction retry_action) {
  return false;
}

bool Tpm2Impl::Sign(const SecureBlob& key_blob,
                    const SecureBlob& input,
                    int bound_pcr_index,
                    SecureBlob* signature) {
  TrunksClientContext* trunks;
  if (!GetTrunksContext(&trunks)) {
    return false;
  }
  trunks::AuthorizationDelegate* delegate;
  std::unique_ptr<trunks::PolicySession> policy_session;
  std::unique_ptr<trunks::HmacSession> hmac_session;
  TPM_RC result;
  if (bound_pcr_index >= 0) {
    policy_session = trunks->factory->GetPolicySession();
    result = policy_session->StartUnboundSession(false);
    if (result != TPM_RC_SUCCESS) {
      LOG(ERROR) << "Error starting policy session: " << GetErrorString(result);
      return false;
    }
    result = policy_session->PolicyPCR(bound_pcr_index, "");
    if (result != TPM_RC_SUCCESS) {
      LOG(ERROR) << "Error creating PCR policy: " << GetErrorString(result);
      return false;
    }
    delegate = policy_session->GetDelegate();
  } else {
    hmac_session = trunks->factory->GetHmacSession();
    result = hmac_session->StartUnboundSession(true);
    if (result != TPM_RC_SUCCESS) {
      LOG(ERROR) << "Error starting hmac session: " << GetErrorString(result);
      return false;
    }
    hmac_session->SetEntityAuthorizationValue("");
    delegate = hmac_session->GetDelegate();
  }

  ScopedKeyHandle handle;
  TpmRetryAction retry = LoadWrappedKey(key_blob, &handle);
  if (retry != kTpmRetryNone) {
    LOG(ERROR) << "Error loading pcr bound key.";
    return false;
  }
  std::string tpm_signature;
  result = trunks->tpm_utility->Sign(handle.value(), trunks::TPM_ALG_RSASSA,
                                     trunks::TPM_ALG_SHA256, input.to_string(),
                                     delegate, &tpm_signature);
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error signing: " << GetErrorString(result);
    return false;
  }
  signature->assign(tpm_signature.begin(), tpm_signature.end());
  return true;
}

bool Tpm2Impl::CreatePCRBoundKey(int pcr_index,
                                 const SecureBlob& pcr_value,
                                 SecureBlob* key_blob,
                                 SecureBlob* public_key_der,
                                 SecureBlob* creation_blob) {
  CHECK(key_blob) << "No key blob argument provided.";
  CHECK(creation_blob) << "No creation blob argument provided.";
  TrunksClientContext* trunks;
  if (!GetTrunksContext(&trunks)) {
    return false;
  }
  std::string policy_digest;
  TPM_RC result = trunks->tpm_utility->GetPolicyDigestForPcrValue(
      pcr_index, pcr_value.to_string(), &policy_digest);
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error getting policy digest: " << GetErrorString(result);
    return false;
  }
  std::string tpm_key_blob;
  std::string tpm_creation_blob;
  std::unique_ptr<trunks::AuthorizationDelegate> delegate =
      trunks->factory->GetPasswordAuthorization("");
  result = trunks->tpm_utility->CreateRSAKeyPair(
      trunks::TpmUtility::kSignKey, kDefaultTpmRsaModulusSize,
      kDefaultTpmPublicExponent,
      "",  // No authorization
      policy_digest,
      true,  // use_only_policy_authorization
      pcr_index, delegate.get(), &tpm_key_blob,
      &tpm_creation_blob /* No creation_blob */);
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error creating a pcr bound key: " << GetErrorString(result);
    return false;
  }
  key_blob->assign(tpm_key_blob.begin(), tpm_key_blob.end());
  creation_blob->assign(tpm_creation_blob.begin(), tpm_creation_blob.end());

  // if |public_key_der| is present, create and assign it.
  if (public_key_der) {
    trunks::TPM2B_PUBLIC public_data;
    trunks::TPM2B_PRIVATE private_data;
    if (!trunks->factory->GetBlobParser()->ParseKeyBlob(
            key_blob->to_string(), &public_data, &private_data)) {
      return false;
    }
    if (!PublicAreaToPublicKeyDER(public_data.public_area, public_key_der)) {
      return false;
    }
  }
  return true;
}

bool Tpm2Impl::VerifyPCRBoundKey(int pcr_index,
                                 const SecureBlob& pcr_value,
                                 const SecureBlob& key_blob,
                                 const SecureBlob& creation_blob) {
  TrunksClientContext* trunks;
  if (!GetTrunksContext(&trunks)) {
    return false;
  }
  // First we verify that the PCR were in a known good state at the time of
  // Key creation.
  trunks::TPM2B_CREATION_DATA creation_data;
  trunks::TPM2B_DIGEST creation_hash;
  trunks::TPMT_TK_CREATION creation_ticket;
  if (!trunks->factory->GetBlobParser()->ParseCreationBlob(
          creation_blob.to_string(), &creation_data, &creation_hash,
          &creation_ticket)) {
    LOG(ERROR) << "Error parsing creation_blob.";
    return false;
  }
  trunks::TPML_PCR_SELECTION& pcr_select =
      creation_data.creation_data.pcr_select;
  if (pcr_select.count != 1) {
    LOG(ERROR) << "Creation data missing creation PCR value.";
    return false;
  }
  if (pcr_select.pcr_selections[0].hash != trunks::TPM_ALG_SHA256) {
    LOG(ERROR) << "Creation PCR extended with wrong hash algorithm.";
    return false;
  }
  if (pcr_select.pcr_selections[0].pcr_select[pcr_index / 8] !=
      (1 << (pcr_index % 8))) {
    LOG(ERROR) << "Incorrect creation PCR specified.";
    return false;
  }
  SecureBlob expected_pcr_digest = CryptoLib::Sha256(pcr_value);
  if (creation_data.creation_data.pcr_digest.size !=
      expected_pcr_digest.size()) {
    LOG(ERROR) << "Incorrect PCR digest size.";
    return false;
  }
  if (memcmp(creation_data.creation_data.pcr_digest.buffer,
             expected_pcr_digest.data(), expected_pcr_digest.size()) != 0) {
    LOG(ERROR) << "Incorrect PCR digest value.";
    return false;
  }
  // Then we certify that the key was created by the TPM.
  ScopedKeyHandle scoped_handle;
  if (LoadWrappedKey(key_blob, &scoped_handle) != Tpm::kTpmRetryNone) {
    return false;
  }
  TPM_RC result = trunks->tpm_utility->CertifyCreation(
      scoped_handle.value(), creation_blob.to_string());
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error certifying that key was created by TPM: "
               << trunks::GetErrorString(result);
    return false;
  }
  // Finally we verify that the key's policy_digest is the expected value.
  std::unique_ptr<trunks::PolicySession> trial_session =
      trunks->factory->GetTrialSession();
  result = trial_session->StartUnboundSession(true);
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error starting a trial session: " << GetErrorString(result);
    return false;
  }
  result = trial_session->PolicyPCR(pcr_index, pcr_value.to_string());
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error restricting trial policy to pcr value: "
               << GetErrorString(result);
    return false;
  }
  std::string policy_digest;
  result = trial_session->GetDigest(&policy_digest);
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error getting policy digest: " << GetErrorString(result);
    return false;
  }
  trunks::TPMT_PUBLIC public_area;
  result = trunks->tpm_utility->GetKeyPublicArea(scoped_handle.value(),
                                                 &public_area);
  if (result != TPM_RC_SUCCESS) {
    return false;
  }
  if (public_area.auth_policy.size != policy_digest.size()) {
    LOG(ERROR) << "Key auth policy and policy digest are of different length."
               << public_area.auth_policy.size << "," << policy_digest.size();
    return false;
  } else if (memcmp(public_area.auth_policy.buffer, policy_digest.data(),
                    policy_digest.size()) != 0) {
    LOG(ERROR) << "Key auth policy is different from policy digest.";
    return false;
  } else if (public_area.object_attributes & trunks::kUserWithAuth) {
    LOG(ERROR) << "Key authorization is not restricted to policy.";
    return false;
  }
  return true;
}

bool Tpm2Impl::ExtendPCR(int pcr_index, const SecureBlob& extension) {
  TrunksClientContext* trunks;
  if (!GetTrunksContext(&trunks)) {
    return false;
  }
  std::unique_ptr<trunks::AuthorizationDelegate> delegate =
      trunks->factory->GetPasswordAuthorization("");
  TPM_RC result = trunks->tpm_utility->ExtendPCR(
      pcr_index, extension.to_string(), delegate.get());
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error extending PCR: " << GetErrorString(result);
    return false;
  }
  return true;
}

bool Tpm2Impl::ReadPCR(int pcr_index, SecureBlob* pcr_value) {
  CHECK(pcr_value);
  TrunksClientContext* trunks;
  if (!GetTrunksContext(&trunks)) {
    return false;
  }
  std::string pcr_digest;
  TPM_RC result = trunks->tpm_utility->ReadPCR(pcr_index, &pcr_digest);
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error reading from PCR: " << GetErrorString(result);
    return false;
  }
  pcr_value->assign(pcr_digest.begin(), pcr_digest.end());
  return true;
}

bool Tpm2Impl::WrapRsaKey(const SecureBlob& public_modulus,
                          const SecureBlob& prime_factor,
                          SecureBlob* wrapped_key) {
  TrunksClientContext* trunks;
  if (!GetTrunksContext(&trunks)) {
    return false;
  }
  std::string key_blob;
  std::unique_ptr<trunks::AuthorizationDelegate> delegate =
      trunks->factory->GetPasswordAuthorization("");
  TPM_RC result = trunks->tpm_utility->ImportRSAKey(
      trunks::TpmUtility::kDecryptKey, public_modulus.to_string(),
      kDefaultTpmPublicExponent, prime_factor.to_string(),
      "",  // No authorization,
      delegate.get(), &key_blob);
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error creating SRK wrapped key: " << GetErrorString(result);
    return false;
  }
  wrapped_key->assign(key_blob.begin(), key_blob.end());
  return true;
}

Tpm::TpmRetryAction Tpm2Impl::LoadWrappedKey(const SecureBlob& wrapped_key,
                                             ScopedKeyHandle* key_handle) {
  CHECK(key_handle);
  TrunksClientContext* trunks;
  if (!GetTrunksContext(&trunks)) {
    return Tpm::kTpmRetryFailNoRetry;
  }
  trunks::TPM_HANDLE handle;
  std::unique_ptr<trunks::AuthorizationDelegate> delegate =
      trunks->factory->GetPasswordAuthorization("");
  TPM_RC result = trunks->tpm_utility->LoadKey(wrapped_key.to_string(),
                                               delegate.get(), &handle);
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error loading SRK wrapped key: " << GetErrorString(result);
    return Tpm::kTpmRetryFailNoRetry;
  }
  key_handle->reset(this, handle);
  return Tpm::kTpmRetryNone;
}

bool Tpm2Impl::LegacyLoadCryptohomeKey(ScopedKeyHandle* key_handle,
                                       SecureBlob* key_blob) {
  // This doesn't apply to devices with TPM 2.0.
  return false;
}

void Tpm2Impl::CloseHandle(TpmKeyHandle key_handle) {
  TrunksClientContext* trunks;
  if (!GetTrunksContext(&trunks)) {
    return;
  }
  TPM_RC result =
      trunks->factory->GetTpm()->FlushContextSync(key_handle, nullptr);
  if (result != TPM_RC_SUCCESS) {
    LOG(WARNING) << "Error flushing tpm handle " << key_handle << ": "
                 << GetErrorString(result);
  }
}

Tpm::TpmRetryAction Tpm2Impl::EncryptBlob(TpmKeyHandle key_handle,
                                          const SecureBlob& plaintext,
                                          const SecureBlob& key,
                                          SecureBlob* ciphertext) {
  CHECK(ciphertext);
  TrunksClientContext* trunks;
  if (!GetTrunksContext(&trunks)) {
    return Tpm::kTpmRetryFailNoRetry;
  }
  std::string tpm_ciphertext;
  TPM_RC result = trunks->tpm_utility->AsymmetricEncrypt(
      key_handle, trunks::TPM_ALG_OAEP, trunks::TPM_ALG_SHA256,
      plaintext.to_string(), nullptr, &tpm_ciphertext);
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error encrypting plaintext: " << GetErrorString(result);
    return Tpm::kTpmRetryFailNoRetry;
  }
  if (!CryptoLib::ObscureRSAMessage(SecureBlob(tpm_ciphertext), key,
                                    ciphertext)) {
    LOG(ERROR) << "Error obscuring tpm encrypted blob.";
    return Tpm::kTpmRetryFailNoRetry;
  }
  return Tpm::kTpmRetryNone;
}

Tpm::TpmRetryAction Tpm2Impl::DecryptBlob(TpmKeyHandle key_handle,
                                          const SecureBlob& ciphertext,
                                          const SecureBlob& key,
                                          SecureBlob* plaintext) {
  CHECK(plaintext);
  TrunksClientContext* trunks;
  if (!GetTrunksContext(&trunks)) {
    return Tpm::kTpmRetryFailNoRetry;
  }
  SecureBlob local_data;
  if (!CryptoLib::UnobscureRSAMessage(ciphertext, key, &local_data)) {
    LOG(ERROR) << "Error unobscureing message.";
    return Tpm::kTpmRetryFailNoRetry;
  }
  std::unique_ptr<trunks::AuthorizationDelegate> delegate =
      trunks->factory->GetPasswordAuthorization("");
  std::string tpm_plaintext;
  TPM_RC result = trunks->tpm_utility->AsymmetricDecrypt(
      key_handle, trunks::TPM_ALG_OAEP, trunks::TPM_ALG_SHA256,
      local_data.to_string(), delegate.get(), &tpm_plaintext);
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error encrypting plaintext: " << GetErrorString(result);
    return Tpm::kTpmRetryFailNoRetry;
  }
  plaintext->assign(tpm_plaintext.begin(), tpm_plaintext.end());
  return Tpm::kTpmRetryNone;
}

Tpm::TpmRetryAction Tpm2Impl::GetPublicKeyHash(TpmKeyHandle key_handle,
                                               SecureBlob* hash) {
  CHECK(hash);
  TrunksClientContext* trunks;
  if (!GetTrunksContext(&trunks)) {
    return Tpm::kTpmRetryFailNoRetry;
  }
  trunks::TPMT_PUBLIC public_data;
  TPM_RC result =
      trunks->tpm_utility->GetKeyPublicArea(key_handle, &public_data);
  if (result != TPM_RC_SUCCESS) {
    LOG(ERROR) << "Error getting key public area: " << GetErrorString(result);
    return Tpm::kTpmRetryFailNoRetry;
  }
  std::string public_modulus =
      trunks::StringFrom_TPM2B_PUBLIC_KEY_RSA(public_data.unique.rsa);
  *hash = CryptoLib::Sha256(SecureBlob(public_modulus));
  return Tpm::kTpmRetryNone;
}

void Tpm2Impl::GetStatus(TpmKeyHandle key, TpmStatusInfo* status) {
  memset(status, 0, sizeof(TpmStatusInfo));
  TrunksClientContext* trunks;
  if (!GetTrunksContext(&trunks)) {
    return;
  }
  status->this_instance_has_context = true;
  status->this_instance_has_key_handle = (key != 0);
  status->last_tpm_error = trunks->tpm_state->Initialize();
  if (status->last_tpm_error != TPM_RC_SUCCESS) {
    return;
  }
  status->can_connect = true;
  trunks::TPMT_PUBLIC public_srk;
  status->last_tpm_error = trunks->tpm_utility->GetKeyPublicArea(
      trunks::kRSAStorageRootKey, &public_srk);
  if (status->last_tpm_error != TPM_RC_SUCCESS) {
    return;
  }
  status->can_load_srk = true;
  status->can_load_srk_public_key = true;

  // Check the Cryptohome key by using what we have been told.
  status->has_cryptohome_key = (key != 0);

  if (status->has_cryptohome_key) {
    // Check encryption (we don't care about the contents, just whether or not
    // there was an error)
    SecureBlob data(16);
    SecureBlob password(16);
    SecureBlob salt(8);
    SecureBlob data_out(16);
    memset(data.data(), 'A', data.size());
    memset(password.data(), 'B', password.size());
    memset(salt.data(), 'C', salt.size());
    memset(data_out.data(), 'D', data_out.size());
    SecureBlob aes_key;
    CryptoLib::PasskeyToAesKey(password, salt, 13, &aes_key, NULL);
    if (EncryptBlob(key, data, aes_key, &data_out) != kTpmRetryNone) {
      return;
    }
    status->can_encrypt = true;

    // Check decryption (we don't care about the contents, just whether or not
    // there was an error)
    if (DecryptBlob(key, data_out, aes_key, &data) != kTpmRetryNone) {
      return;
    }
    status->can_decrypt = true;
  }
}

bool Tpm2Impl::GetDictionaryAttackInfo(int* counter,
                                       int* threshold,
                                       bool* lockout,
                                       int* seconds_remaining) {
  if (!UpdateTpmStatus(RefreshType::FORCE_REFRESH)) {
    return false;
  }
  *counter = tpm_status_.dictionary_attack_counter();
  *threshold = tpm_status_.dictionary_attack_threshold();
  *lockout = tpm_status_.dictionary_attack_lockout_in_effect();
  *seconds_remaining =
      tpm_status_.dictionary_attack_lockout_seconds_remaining();
  return true;
}

bool Tpm2Impl::ResetDictionaryAttackMitigation(
    const SecureBlob& delegate_blob,
    const SecureBlob& delegate_secret) {
  if (!UpdateTpmStatus(RefreshType::REFRESH_IF_NEEDED)) {
    return false;
  }
  if (!tpm_status_.local_data().has_lockout_password()) {
    return false;
  }
  TrunksClientContext* trunks;
  if (!GetTrunksContext(&trunks)) {
    return false;
  }
  auto authorization = trunks->factory->GetPasswordAuthorization(
      tpm_status_.local_data().lockout_password());
  return (trunks->tpm_utility->ResetDictionaryAttackLock(authorization.get()) ==
          TPM_RC_SUCCESS);
}

bool Tpm2Impl::GetTrunksContext(TrunksClientContext** trunks) {
  if (has_external_trunks_context_) {
    *trunks = &external_trunks_context_;
    return true;
  }
  base::PlatformThreadId thread_id = base::PlatformThread::CurrentId();
  if (trunks_contexts_.count(thread_id) == 0) {
    std::unique_ptr<TrunksClientContext> new_context(new TrunksClientContext);
    new_context->factory_impl = base::MakeUnique<trunks::TrunksFactoryImpl>();
    if (!new_context->factory_impl->Initialize()) {
      LOG(ERROR) << "Failed to initialize trunks factory.";
      return false;
    }
    new_context->factory = new_context->factory_impl.get();
    new_context->tpm_state = new_context->factory->GetTpmState();
    new_context->tpm_utility = new_context->factory->GetTpmUtility();
    trunks_contexts_[thread_id] = std::move(new_context);
  }
  *trunks = trunks_contexts_[thread_id].get();
  return true;
}

bool Tpm2Impl::PublicAreaToPublicKeyDER(const trunks::TPMT_PUBLIC& public_area,
                                        brillo::SecureBlob* public_key_der) {
  crypto::ScopedRSA rsa(RSA_new());
  rsa.get()->e = BN_new();
  CHECK(rsa.get()->e) << "Error setting exponent for RSA.";
  BN_set_word(rsa.get()->e, kDefaultTpmPublicExponent);
  rsa.get()->n = BN_bin2bn(public_area.unique.rsa.buffer,
                           public_area.unique.rsa.size, nullptr);
  CHECK(rsa.get()->n) << "Error setting modulus for RSA.";
  int der_length = i2d_RSAPublicKey(rsa.get(), nullptr);
  if (der_length < 0) {
    LOG(ERROR) << "Failed to get DER-encoded public key length.";
    return false;
  }
  public_key_der->resize(der_length);
  unsigned char* der_buffer = public_key_der->data();
  der_length = i2d_RSAPublicKey(rsa.get(), &der_buffer);
  if (der_length < 0) {
    LOG(ERROR) << "Failed to DER-encode public key.";
    return false;
  }
  return true;
}

bool Tpm2Impl::InitializeTpmManagerClients() {
  if (!tpm_manager_thread_.IsRunning() &&
      !tpm_manager_thread_.StartWithOptions(base::Thread::Options(
          base::MessageLoopForIO::TYPE_IO, 0 /* Default stack size. */))) {
    LOG(ERROR) << "Failed to start tpm_manager thread.";
    return false;
  }
  if (!tpm_owner_ || !tpm_nvram_) {
    base::WaitableEvent event(true /* manual_reset */,
                              false /* initially_signaled */);
    tpm_manager_thread_.task_runner()->PostTask(
        FROM_HERE, base::Bind([this, &event]() {
          default_tpm_owner_ =
              base::MakeUnique<tpm_manager::TpmOwnershipDBusProxy>();
          default_tpm_nvram_ =
              base::MakeUnique<tpm_manager::TpmNvramDBusProxy>();
          if (default_tpm_owner_->Initialize()) {
            tpm_owner_ = default_tpm_owner_.get();
          }
          if (default_tpm_nvram_->Initialize()) {
            tpm_nvram_ = default_tpm_nvram_.get();
          }
          event.Signal();
        }));
    event.Wait();
  }
  if (!tpm_owner_ || !tpm_nvram_) {
    LOG(ERROR) << "Failed to initialize tpm_managerd clients.";
    return false;
  }
  return true;
}

template <typename ReplyProtoType, typename MethodType>
void Tpm2Impl::SendTpmManagerRequestAndWait(const MethodType& method,
                                            ReplyProtoType* reply_proto) {
  base::WaitableEvent event(true /* manual_reset */,
                            false /* initially_signaled */);
  auto callback =
      base::Bind([reply_proto, &event](const ReplyProtoType& reply) {
        *reply_proto = reply;
        event.Signal();
      });
  tpm_manager_thread_.task_runner()->PostTask(
      FROM_HERE,
      base::Bind([this, &method, &callback]() {
        method.Run(callback); }));
  event.Wait();
}

bool Tpm2Impl::UpdateTpmStatus(RefreshType refresh_type) {
  if (!InitializeTpmManagerClients()) {
    return false;
  }
  if (refresh_type != RefreshType::FORCE_REFRESH &&
      tpm_status_.status() == tpm_manager::STATUS_SUCCESS &&
      tpm_status_.enabled() && tpm_status_.owned()) {
    // We have a valid status and we're not waiting on ownership so we don't
    // need to refresh our cached status.
    return true;
  }
  auto method = base::Bind(&tpm_manager::TpmOwnershipInterface::GetTpmStatus,
                           base::Unretained(tpm_owner_),
                           tpm_manager::GetTpmStatusRequest());
  SendTpmManagerRequestAndWait(method, &tpm_status_);
  return (tpm_status_.status() == tpm_manager::STATUS_SUCCESS);
}

}  // namespace cryptohome