tpm_manager/server/tpm_nvram_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.

#include "tpm_manager/server/tpm_nvram_impl.h"

#include <arpa/inet.h>

#include <algorithm>
#include <string>
#include <unordered_set>
#include <vector>

#include <base/logging.h>
#include <base/stl_util.h>
#include <libhwsec/overalls/overalls_api.h>
#include <tpm_manager/proto_bindings/tpm_manager.pb.h>

#include "tpm_manager/server/local_data_store.h"
#include "tpm_manager/server/tpm_util.h"

namespace tpm_manager {

using ::hwsec::overalls::GetOveralls;
using trousers::ScopedTssMemory;
using trousers::ScopedTssNvStore;
using trousers::ScopedTssPcrs;

namespace {

// PCR0 at locality 1 is used to differentiate between developed and normal
// mode. Restricting nvram to the PCR0 value in locality 1 prevents nvram from
// persisting across mode switch.
const unsigned int kTpmBootPCR = 0;
const unsigned int kTpmPCRLocality = 1;

void MapAttributesFromTpm(TPM_NV_PER_ATTRIBUTES tpm_flags,
                          std::vector<NvramSpaceAttribute>* attributes) {
  if (tpm_flags & TPM_NV_PER_WRITEDEFINE)
    attributes->push_back(NVRAM_PERSISTENT_WRITE_LOCK);
  if (tpm_flags & TPM_NV_PER_WRITE_STCLEAR)
    attributes->push_back(NVRAM_BOOT_WRITE_LOCK);
  if (tpm_flags & TPM_NV_PER_READ_STCLEAR)
    attributes->push_back(NVRAM_BOOT_READ_LOCK);
  if (tpm_flags & TPM_NV_PER_AUTHWRITE)
    attributes->push_back(NVRAM_WRITE_AUTHORIZATION);
  if (tpm_flags & TPM_NV_PER_AUTHREAD)
    attributes->push_back(NVRAM_READ_AUTHORIZATION);
  if (tpm_flags & TPM_NV_PER_GLOBALLOCK)
    attributes->push_back(NVRAM_GLOBAL_LOCK);
  if (tpm_flags & TPM_NV_PER_PPREAD)
    attributes->push_back(NVRAM_PLATFORM_READ);
  if (tpm_flags & TPM_NV_PER_PPWRITE)
    attributes->push_back(NVRAM_PLATFORM_WRITE);
  if (tpm_flags & TPM_NV_PER_OWNERWRITE)
    attributes->push_back(NVRAM_OWNER_WRITE);
  if (tpm_flags & TPM_NV_PER_OWNERREAD)
    attributes->push_back(NVRAM_OWNER_READ);
}

TPM_NV_PER_ATTRIBUTES MapAttributesToTpm(
    const std::vector<NvramSpaceAttribute>& attributes) {
  TPM_NV_PER_ATTRIBUTES tpm_flags = 0;
  for (auto attribute : attributes) {
    switch (attribute) {
      case NVRAM_PERSISTENT_WRITE_LOCK:
        tpm_flags |= TPM_NV_PER_WRITEDEFINE;
        break;
      case NVRAM_BOOT_WRITE_LOCK:
        tpm_flags |= TPM_NV_PER_WRITE_STCLEAR;
        break;
      case NVRAM_BOOT_READ_LOCK:
        tpm_flags |= TPM_NV_PER_READ_STCLEAR;
        break;
      case NVRAM_WRITE_AUTHORIZATION:
        tpm_flags |= TPM_NV_PER_AUTHWRITE;
        break;
      case NVRAM_READ_AUTHORIZATION:
        tpm_flags |= TPM_NV_PER_AUTHREAD;
        break;
      case NVRAM_GLOBAL_LOCK:
        tpm_flags |= TPM_NV_PER_GLOBALLOCK;
        break;
      case NVRAM_PLATFORM_READ:
        tpm_flags |= TPM_NV_PER_PPREAD;
        break;
      case NVRAM_PLATFORM_WRITE:
        tpm_flags |= TPM_NV_PER_PPWRITE;
        break;
      case NVRAM_OWNER_WRITE:
        tpm_flags |= TPM_NV_PER_OWNERWRITE;
        break;
      case NVRAM_OWNER_READ:
        tpm_flags |= TPM_NV_PER_OWNERREAD;
        break;
      default:
        break;
    }
  }
  return tpm_flags;
}

NvramResult MapTpmError(TSS_RESULT tpm_error) {
  switch (TPM_ERROR(tpm_error)) {
    case TPM_SUCCESS:
      return NVRAM_RESULT_SUCCESS;
    case TPM_E_BAD_PARAMETER:
    case TPM_E_PER_NOWRITE:
    case TPM_E_AUTH_CONFLICT:
      return NVRAM_RESULT_INVALID_PARAMETER;
    case TPM_E_AREA_LOCKED:
    case TPM_E_READ_ONLY:
    case TPM_E_WRITE_LOCKED:
    case TPM_E_DISABLED_CMD:
      return NVRAM_RESULT_OPERATION_DISABLED;
    case TPM_E_AUTHFAIL:
    case TPM_E_NO_NV_PERMISSION:
    case TPM_E_WRONGPCRVAL:
      return NVRAM_RESULT_ACCESS_DENIED;
    case TPM_E_NOSPACE:
    case TPM_E_RESOURCES:
    case TPM_E_SIZE:
      return NVRAM_RESULT_INSUFFICIENT_SPACE;
    case TPM_E_BADINDEX:
    case TPM_E_BAD_HANDLE:
      return NVRAM_RESULT_SPACE_DOES_NOT_EXIST;
  }
  return NVRAM_RESULT_DEVICE_ERROR;
}

// Returns whether |attributes| contains at least one key of |keys|.
bool HasAnyAttribute(const std::unordered_set<NvramSpaceAttribute>& key_set,
                     const std::vector<NvramSpaceAttribute>& attributes) {
  for (const auto attr : attributes) {
    if (key_set.find(attr) != key_set.end()) {
      return true;
    }
  }

  return false;
}

}  // namespace

TpmNvramImpl::TpmNvramImpl(LocalDataStore* local_data_store)
    : local_data_store_(local_data_store) {}

NvramResult TpmNvramImpl::DefineSpace(
    uint32_t index,
    size_t size,
    const std::vector<NvramSpaceAttribute>& attributes,
    const std::string& authorization_value,
    NvramSpacePolicy policy) {
  std::string owner_password;
  if (!GetOwnerPassword(&owner_password)) {
    return NVRAM_RESULT_OPERATION_DISABLED;
  }

  TpmConnection owner_connection(owner_password);
  TSS_HCONTEXT connection_context = owner_connection.GetContext();

  // Bind to PCR0.
  ScopedTssPcrs scoped_pcr_handle(connection_context);
  if (policy == NVRAM_POLICY_PCR0) {
    if (!SetCompositePcr0(&scoped_pcr_handle, &owner_connection)) {
      return NVRAM_RESULT_DEVICE_ERROR;
    }
  }

  ScopedTssNvStore nv_handle(connection_context);
  trousers::ScopedTssPolicy policy_handle(connection_context);

  static const std::unordered_set<NvramSpaceAttribute> auth_attributes(
      {NVRAM_READ_AUTHORIZATION, NVRAM_WRITE_AUTHORIZATION});
  bool need_auth_policy = HasAnyAttribute(auth_attributes, attributes);
  if (!InitializeNvramHandleWithPolicy(index, need_auth_policy,
                                       authorization_value, &nv_handle,
                                       &policy_handle, &owner_connection)) {
    return NVRAM_RESULT_DEVICE_ERROR;
  }

  TSS_RESULT result;
  result = GetOveralls()->Ospi_SetAttribUint32(
      nv_handle, TSS_TSPATTRIB_NV_DATASIZE, 0, size);
  if (TPM_ERROR(result)) {
    TPM_LOG(ERROR, result) << "Could not set size on NVRAM object: " << size;
    return NVRAM_RESULT_DEVICE_ERROR;
  }
  // Set permissions attributes.
  result = GetOveralls()->Ospi_SetAttribUint32(nv_handle,
                                               TSS_TSPATTRIB_NV_PERMISSIONS, 0,
                                               MapAttributesToTpm(attributes));
  if (TPM_ERROR(result)) {
    TPM_LOG(ERROR, result) << "Could not set permissions on NVRAM object";
    return NVRAM_RESULT_DEVICE_ERROR;
  }

  result =
      GetOveralls()->Ospi_NV_DefineSpace(nv_handle, scoped_pcr_handle, /*Read*/
                                         scoped_pcr_handle /*Write*/);
  if (TPM_ERROR(result)) {
    TPM_LOG(ERROR, result) << "Could not define NVRAM space: " << index;
    return MapTpmError(result);
  }
  return NVRAM_RESULT_SUCCESS;
}

NvramResult TpmNvramImpl::DestroySpace(uint32_t index) {
  std::string owner_password;
  if (!GetOwnerPassword(&owner_password)) {
    return NVRAM_RESULT_OPERATION_DISABLED;
  }
  TpmConnection owner_connection(owner_password);

  NvramResult nvram_result =
      GetSpaceInfo(index, nullptr, nullptr, nullptr, nullptr, nullptr);
  if (nvram_result == NVRAM_RESULT_SPACE_DOES_NOT_EXIST) {
    LOG(INFO) << "NVRAM index is already undefined.";
    return NVRAM_RESULT_SUCCESS;
  } else if (nvram_result != NVRAM_RESULT_SUCCESS) {
    return nvram_result;
  }

  ScopedTssNvStore nv_handle(owner_connection.GetContext());
  if (!InitializeNvramHandle(index, &nv_handle, &owner_connection)) {
    return NVRAM_RESULT_DEVICE_ERROR;
  }
  TSS_RESULT result = GetOveralls()->Ospi_NV_ReleaseSpace(nv_handle);
  if (TPM_ERROR(result)) {
    TPM_LOG(ERROR, result) << "Could not release NVRAM space: " << index;
    return MapTpmError(result);
  }
  return NVRAM_RESULT_SUCCESS;
}

NvramResult TpmNvramImpl::WriteSpace(uint32_t index,
                                     const std::string& data,
                                     const std::string& authorization_value) {
  std::vector<NvramSpaceAttribute> attributes;
  NvramResult result =
      GetSpaceInfo(index, nullptr, nullptr, nullptr, &attributes, nullptr);
  if (result != NVRAM_RESULT_SUCCESS) {
    return result;
  }

  TSS_HCONTEXT connection_context = tpm_connection_.GetContext();
  ScopedTssNvStore nv_handle(connection_context);
  trousers::ScopedTssPolicy policy_handle(connection_context);

  static const std::unordered_set<NvramSpaceAttribute> auth_attributes(
      {NVRAM_OWNER_WRITE, NVRAM_WRITE_AUTHORIZATION});
  bool need_auth_policy = HasAnyAttribute(auth_attributes, attributes);
  if (!InitializeNvramHandleWithPolicy(index, need_auth_policy,
                                       authorization_value, &nv_handle,
                                       &policy_handle, &tpm_connection_)) {
    return NVRAM_RESULT_DEVICE_ERROR;
  }

  TSS_RESULT tpm_result = GetOveralls()->Ospi_NV_WriteValue(
      nv_handle, 0 /* offset */, data.size(),
      reinterpret_cast<BYTE*>(const_cast<char*>(data.data())));
  if (TPM_ERROR(tpm_result)) {
    TPM_LOG(ERROR, tpm_result) << "Could not write to NVRAM space: " << index;
    return MapTpmError(tpm_result);
  }
  return NVRAM_RESULT_SUCCESS;
}

NvramResult TpmNvramImpl::ReadSpace(uint32_t index,
                                    std::string* data,
                                    const std::string& authorization_value) {
  if (!data) {
    LOG(ERROR) << __func__ << ": data is uninitialized.";
    return NVRAM_RESULT_INVALID_PARAMETER;
  }

  return ReadSpaceInternal(index, authorization_value, data);
}

NvramResult TpmNvramImpl::LockSpace(uint32_t index,
                                    bool lock_read,
                                    bool lock_write,
                                    const std::string& authorization_value) {
  // Performing a writelock will unlock the readlock if the readlock existed.
  // Thus, here we should do writelock first.

  NvramResult result = NVRAM_RESULT_SUCCESS;

  if (lock_write) {
    // Per TPM 1.2 specs, writing 0 bytes to an index write-locks the index if
    // it has the NV permission WRITE_STCLEAR or WRITEDEFINE set.
    result = WriteSpace(index, "", authorization_value);
    if (result != NVRAM_RESULT_SUCCESS) {
      LOG(ERROR) << __func__ << ": couldn't write-lock NVRAM space: " << index;
      return result;
    }
  }

  if (lock_read) {
    // ReadSpaceInternal() will try to read 0 bytes from the space if the given
    // buffer is nullptr.
    //
    // Per TPM 1.2 specs, reading 0 bytes from an index read-locks the index if
    // it has the NV permission READ_STCLEAR set.
    result = ReadSpaceInternal(index, authorization_value, nullptr);
    if (result != NVRAM_RESULT_SUCCESS) {
      LOG(ERROR) << __func__ << ": couldn't read-lock NVRAM space: " << index;
      return result;
    }
  }

  return result;
}

NvramResult TpmNvramImpl::ListSpaces(std::vector<uint32_t>* index_list) {
  uint32_t nv_list_data_length = 0;
  ScopedTssMemory nv_list_data(tpm_connection_.GetContext());
  TSS_RESULT result = GetOveralls()->Ospi_TPM_GetCapability(
      tpm_connection_.GetTpm(), TSS_TPMCAP_NV_LIST, 0, nullptr,
      &nv_list_data_length, nv_list_data.ptr());
  if (TPM_ERROR(result)) {
    TPM_LOG(ERROR, result)
        << "Error calling GetOveralls()->Ospi_TPM_GetCapability";
    return MapTpmError(result);
  }
  // Walk the list and check if the index exists.
  uint32_t* nv_list = reinterpret_cast<uint32_t*>(nv_list_data.value());
  uint32_t nv_list_length = nv_list_data_length / sizeof(uint32_t);
  for (uint32_t i = 0; i < nv_list_length; ++i) {
    // TPM data is network byte order.
    index_list->push_back(ntohl(nv_list[i]));
  }
  return NVRAM_RESULT_SUCCESS;
}

NvramResult TpmNvramImpl::GetSpaceInfo(
    uint32_t index,
    uint32_t* size,
    bool* is_read_locked,
    bool* is_write_locked,
    std::vector<NvramSpaceAttribute>* attributes,
    NvramSpacePolicy* policy) {
  UINT32 nv_index_data_length = 0;
  ScopedTssMemory nv_index_data(tpm_connection_.GetContext());
  TSS_RESULT result = GetOveralls()->Ospi_TPM_GetCapability(
      tpm_connection_.GetTpm(), TSS_TPMCAP_NV_INDEX, sizeof(index),
      reinterpret_cast<BYTE*>(&index), &nv_index_data_length,
      nv_index_data.ptr());
  if (TPM_ERROR(result)) {
    TPM_LOG(ERROR, result)
        << "Error calling GetOveralls()->Ospi_TPM_GetCapability";
    return MapTpmError(result);
  }
  UINT64 offset = 0;
  Trspi_UnloadBlob_NV_DATA_PUBLIC(&offset, nv_index_data.value(), nullptr);
  if (nv_index_data_length < offset) {
    LOG(ERROR) << "Not enough data from GetOveralls()->Ospi_TPM_GetCapability.";
    return NVRAM_RESULT_DEVICE_ERROR;
  }
  TPM_NV_DATA_PUBLIC info;
  offset = 0;
  result =
      Trspi_UnloadBlob_NV_DATA_PUBLIC(&offset, nv_index_data.value(), &info);
  if (TPM_ERROR(result)) {
    TPM_LOG(ERROR, result) << "Error calling Trspi_UnloadBlob_NV_DATA_PUBLIC";
    return NVRAM_RESULT_DEVICE_ERROR;
  }
  if (size) {
    *size = info.dataSize;
  }
  if (is_read_locked) {
    *is_read_locked = info.bReadSTClear;
  }
  if (is_write_locked) {
    *is_write_locked = info.bWriteSTClear || info.bWriteDefine;
  }
  if (attributes) {
    MapAttributesFromTpm(info.permission.attributes, attributes);
  }
  if (policy) {
    if (info.pcrInfoWrite.pcrSelection.sizeOfSelect > 0 &&
        (info.pcrInfoWrite.pcrSelection.pcrSelect[0] & 1) != 0) {
      *policy = NVRAM_POLICY_PCR0;
    } else {
      *policy = NVRAM_POLICY_NONE;
    }
  }
  return NVRAM_RESULT_SUCCESS;
}

void TpmNvramImpl::PrunePolicies() {
  // TPM 1.2 doesn't use NVRAM policy.
}

NvramResult TpmNvramImpl::ReadSpaceInternal(
    uint32_t index, const std::string& authorization_value, std::string* data) {
  uint32_t nvram_size;
  std::vector<NvramSpaceAttribute> attributes;
  NvramResult result =
      GetSpaceInfo(index, &nvram_size, nullptr, nullptr, &attributes, nullptr);
  if (result != NVRAM_RESULT_SUCCESS) {
    return result;
  }

  if (nvram_size == 0) {
    LOG(ERROR) << "NvramSize is too small.";
    return NVRAM_RESULT_INSUFFICIENT_SPACE;
  }

  TSS_HCONTEXT connection_context = tpm_connection_.GetContext();
  ScopedTssNvStore nv_handle(connection_context);
  trousers::ScopedTssPolicy policy_handle(connection_context);

  static const std::unordered_set<NvramSpaceAttribute> auth_attributes(
      {NVRAM_OWNER_READ, NVRAM_READ_AUTHORIZATION});
  bool need_auth_policy = HasAnyAttribute(auth_attributes, attributes);
  if (!InitializeNvramHandleWithPolicy(index, need_auth_policy,
                                       authorization_value, &nv_handle,
                                       &policy_handle, &tpm_connection_)) {
    return NVRAM_RESULT_DEVICE_ERROR;
  }

  uint32_t chunk_size = 0;
  ScopedTssMemory space_data(connection_context);
  if (!data) {
    // If data is nullptr, lock the space.
    TSS_RESULT tpm_result = GetOveralls()->Ospi_NV_ReadValue(
        nv_handle, 0, &chunk_size, space_data.ptr());

    return TPM_ERROR(tpm_result) ? MapTpmError(tpm_result)
                                 : NVRAM_RESULT_SUCCESS;
  }

  // The Tpm1.2 Specification defines the maximum read size of 128 bytes.
  // Therefore we have to loop through the data returned.
  constexpr uint32_t kMaxDataSize = 128;
  data->clear();
  data->reserve(nvram_size);
  for (uint32_t offset = 0; offset < nvram_size; offset += chunk_size) {
    chunk_size = std::min(nvram_size - offset, kMaxDataSize);
    TSS_RESULT tpm_result = GetOveralls()->Ospi_NV_ReadValue(
        nv_handle, offset, &chunk_size, space_data.ptr());
    if (TPM_ERROR(tpm_result)) {
      TPM_LOG(ERROR, tpm_result)
          << "Could not read from NVRAM space: " << index;
      data->clear();
      return MapTpmError(tpm_result);
    }
    if (!space_data.value()) {
      LOG(ERROR) << "No data read from NVRAM space: " << index;
      data->clear();
      return NVRAM_RESULT_DEVICE_ERROR;
    }
    CHECK_LE((offset + chunk_size), nvram_size);
    data->append(reinterpret_cast<char*>(space_data.value()), chunk_size);
  }

  return NVRAM_RESULT_SUCCESS;
}

bool TpmNvramImpl::InitializeNvramHandle(uint32_t index,
                                         ScopedTssNvStore* nv_handle,
                                         TpmConnection* connection) {
  TSS_RESULT result = GetOveralls()->Ospi_Context_CreateObject(
      connection->GetContext(), TSS_OBJECT_TYPE_NV, 0, nv_handle->ptr());
  if (TPM_ERROR(result)) {
    TPM_LOG(ERROR, result) << "Could not acquire an NVRAM object handle";
    return false;
  }
  result = GetOveralls()->Ospi_SetAttribUint32(
      nv_handle->value(), TSS_TSPATTRIB_NV_INDEX, 0, index);
  if (TPM_ERROR(result)) {
    TPM_LOG(ERROR, result) << "Could not set index on NVRAM object: " << index;
    return false;
  }
  return true;
}

bool TpmNvramImpl::InitializeNvramHandleWithPolicy(
    uint32_t index,
    bool need_auth_policy,
    const std::string& authorization_value,
    trousers::ScopedTssNvStore* nv_handle,
    trousers::ScopedTssPolicy* policy_handle,
    TpmConnection* connection) {
  if (!InitializeNvramHandle(index, nv_handle, connection)) {
    return false;
  }

  if (!need_auth_policy) {
    return true;
  }

  TSS_RESULT result;
  result = GetOveralls()->Ospi_Context_CreateObject(
      connection->GetContext(), TSS_OBJECT_TYPE_POLICY, TSS_POLICY_USAGE,
      policy_handle->ptr());
  if (TPM_ERROR(result)) {
    TPM_LOG(ERROR, result)
        << "Error calling GetOveralls()->Ospi_Context_CreateObject";
    return false;
  }

  result = GetOveralls()->Ospi_Policy_SetSecret(
      policy_handle->value(), TSS_SECRET_MODE_PLAIN, authorization_value.size(),
      reinterpret_cast<BYTE*>(const_cast<char*>(authorization_value.data())));
  if (TPM_ERROR(result)) {
    TPM_LOG(ERROR, result)
        << "Error calling GetOveralls()->Ospi_Policy_SetSecret";
    return false;
  }

  result = GetOveralls()->Ospi_Policy_AssignToObject(policy_handle->value(),
                                                     nv_handle->value());
  if (TPM_ERROR(result)) {
    TPM_LOG(ERROR, result) << "Could not set NVRAM object policy.";
    return false;
  }

  return true;
}

bool TpmNvramImpl::SetCompositePcr0(ScopedTssPcrs* pcr_handle,
                                    TpmConnection* connection) {
  TSS_RESULT result = GetOveralls()->Ospi_Context_CreateObject(
      connection->GetContext(), TSS_OBJECT_TYPE_PCRS,
      TSS_PCRS_STRUCT_INFO_SHORT, pcr_handle->ptr());
  if (TPM_ERROR(result)) {
    TPM_LOG(ERROR, result) << "Could not acquire PCR object handle";
    return false;
  }
  uint32_t pcr_len;
  ScopedTssMemory pcr_value(connection->GetContext());
  result = GetOveralls()->Ospi_TPM_PcrRead(connection->GetTpm(), kTpmBootPCR,
                                           &pcr_len, pcr_value.ptr());
  if (TPM_ERROR(result)) {
    TPM_LOG(ERROR, result) << "Could not read PCR0 value";
    return false;
  }
  result = GetOveralls()->Ospi_PcrComposite_SetPcrValue(
      pcr_handle->value(), kTpmBootPCR, pcr_len, pcr_value.value());
  if (TPM_ERROR(result)) {
    TPM_LOG(ERROR, result) << "Could not set value for PCR0 in PCR handle";
    return false;
  }
  result = GetOveralls()->Ospi_PcrComposite_SetPcrLocality(pcr_handle->value(),
                                                           kTpmPCRLocality);
  if (TPM_ERROR(result)) {
    TPM_LOG(ERROR, result) << "Could not set locality for PCR0 in PCR handle";
    return false;
  }
  return true;
}

bool TpmNvramImpl::GetOwnerPassword(std::string* owner_password) {
  LocalData local_data;
  if (!local_data_store_->Read(&local_data)) {
    LOG(ERROR) << "Error reading local data for owner password.";
    return false;
  }
  if (local_data.owner_password().empty()) {
    LOG(ERROR) << "No owner password present in tpm local_data.";
    return false;
  }
  owner_password->assign(local_data.owner_password());
  return true;
}

}  // namespace tpm_manager