cryptohome/signature_sealing_backend_test_utils.cc

// Copyright 2018 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 "cryptohome/signature_sealing_backend_test_utils.h"

#include <gmock/gmock.h>

#include "cryptohome/mock_signature_sealing_backend.h"
#include "cryptohome/protobuf_test_utils.h"
#include "cryptohome/signature_sealed_data.pb.h"

using brillo::Blob;
using brillo::BlobToString;
using brillo::SecureBlob;
using testing::_;
using testing::AtLeast;
using testing::DoAll;
using testing::Return;
using testing::SetArgPointee;
using testing::StrictMock;

namespace cryptohome {

SignatureSealedData MakeFakeSignatureSealedData(
    const Blob& public_key_spki_der) {
  constexpr char kFakeTpm2SrkWrappedSecret[] = "ab";
  SignatureSealedData sealed_data;
  // Fill some fields of the protobuf message just to make test/mock assertions
  // more meaningful. Note that it's unimportant that we use TPM2-specific
  // fields here.
  SignatureSealedData_Tpm2PolicySignedData& sealed_data_contents =
      *sealed_data.mutable_tpm2_policy_signed_data();
  sealed_data_contents.set_public_key_spki_der(
      BlobToString(public_key_spki_der));
  sealed_data_contents.set_srk_wrapped_secret(kFakeTpm2SrkWrappedSecret);
  return sealed_data;
}

SignatureSealedCreationMocker::SignatureSealedCreationMocker(
    MockSignatureSealingBackend* mock_backend)
    : mock_backend_(mock_backend) {}

SignatureSealedCreationMocker::~SignatureSealedCreationMocker() = default;

void SignatureSealedCreationMocker::SetUpSuccessfulMock() {
  const SignatureSealedData sealed_data_to_return =
      MakeFakeSignatureSealedData(public_key_spki_der_);
  EXPECT_CALL(*mock_backend_,
              CreateSealedSecret(public_key_spki_der_, key_algorithms_,
                                 pcr_restrictions_, delegate_blob_,
                                 delegate_secret_, _, _))
      .WillOnce(DoAll(SetArgPointee<5>(SecureBlob(secret_value_)),
                      SetArgPointee<6>(sealed_data_to_return), Return(true)));
}

void SignatureSealedCreationMocker::SetUpFailingMock() {
  EXPECT_CALL(*mock_backend_,
              CreateSealedSecret(public_key_spki_der_, key_algorithms_,
                                 pcr_restrictions_, delegate_blob_,
                                 delegate_secret_, _, _))
      .WillOnce(Return(false));
}

SignatureSealedUnsealingMocker::SignatureSealedUnsealingMocker(
    MockSignatureSealingBackend* mock_backend)
    : mock_backend_(mock_backend) {}

SignatureSealedUnsealingMocker::~SignatureSealedUnsealingMocker() = default;

void SignatureSealedUnsealingMocker::SetUpSuccessfulMock() {
  MockUnsealingSession* mock_unsealing_session = AddSessionCreationMock();
  EXPECT_CALL(*mock_unsealing_session, Unseal(challenge_signature_, _))
      .WillOnce(
          DoAll(SetArgPointee<1>(SecureBlob(secret_value_)), Return(true)));
}

void SignatureSealedUnsealingMocker::SetUpCreationFailingMock(
    bool mock_repeatedly) {
  const SignatureSealedData expected_sealed_data =
      MakeFakeSignatureSealedData(public_key_spki_der_);
  auto& expected_call = EXPECT_CALL(
      *mock_backend_,
      CreateUnsealingSessionImpl(ProtobufEquals(expected_sealed_data),
                                 public_key_spki_der_, key_algorithms_,
                                 delegate_blob_, delegate_secret_));
  if (mock_repeatedly)
    expected_call.WillRepeatedly(Return(nullptr));
  else
    expected_call.WillOnce(Return(nullptr));
}

void SignatureSealedUnsealingMocker::SetUpUsealingFailingMock() {
  MockUnsealingSession* mock_unsealing_session = AddSessionCreationMock();
  EXPECT_CALL(*mock_unsealing_session, Unseal(challenge_signature_, _))
      .WillOnce(Return(false));
}

void SignatureSealedUnsealingMocker::SetUpUnsealingNotCalledMock() {
  AddSessionCreationMock();
}

MockUnsealingSession* SignatureSealedUnsealingMocker::AddSessionCreationMock() {
  // The created instance will initially be owned by the
  // CreateUnsealingSessionImpl() method mock, which will then transfer the
  // ownership to its caller.
  StrictMock<MockUnsealingSession>* mock_unsealing_session =
      new StrictMock<MockUnsealingSession>;
  const SignatureSealedData expected_sealed_data =
      MakeFakeSignatureSealedData(public_key_spki_der_);
  EXPECT_CALL(*mock_backend_,
              CreateUnsealingSessionImpl(ProtobufEquals(expected_sealed_data),
                                         public_key_spki_der_, key_algorithms_,
                                         delegate_blob_, delegate_secret_))
      .WillOnce(Return(mock_unsealing_session))
      .RetiresOnSaturation();
  EXPECT_CALL(*mock_unsealing_session, GetChallengeAlgorithm())
      .WillRepeatedly(Return(chosen_algorithm_));
  EXPECT_CALL(*mock_unsealing_session, GetChallengeValue())
      .WillRepeatedly(Return(challenge_value_));
  return mock_unsealing_session;
}

}  // namespace cryptohome