// Copyright 2018 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
////////////////////////////////////////////////////////////////////////////////

#include "tink/subtle/aes_gcm_siv_boringssl.h"

#include <memory>
#include <string>
#include <vector>

#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/status/status.h"
#include "absl/strings/escaping.h"
#include "absl/strings/str_cat.h"
#include "tink/aead/internal/wycheproof_aead.h"
#include "tink/config/tink_fips.h"
#include "tink/internal/ssl_util.h"
#include "tink/subtle/subtle_util.h"
#include "tink/util/secret_data.h"
#include "tink/util/statusor.h"
#include "tink/util/test_matchers.h"

namespace crypto {
namespace tink {
namespace subtle {
namespace {

constexpr absl::string_view kKey256Hex =
    "000102030405060708090a0b0c0d0e0f000102030405060708090a0b0c0d0e0f";
constexpr absl::string_view kMessage = "Some data to encrypt.";
constexpr absl::string_view kAssociatedData = "Some data to authenticate.";

constexpr int kIvSizeInBytes = 12;
constexpr int kTagSizeInBytes = 16;

using ::crypto::tink::test::IsOk;
using ::crypto::tink::test::StatusIs;
using ::testing::AllOf;
using ::testing::Eq;
using ::testing::Not;
using ::testing::SizeIs;
using ::testing::TestWithParam;
using ::testing::ValuesIn;

TEST(AesGcmSivBoringSslTest, EncryptDecrypt) {
  if (IsFipsModeEnabled()) {
    GTEST_SKIP() << "Not supported in FIPS-only mode";
  }

  util::SecretData key =
      util::SecretDataFromStringView(absl::HexStringToBytes(kKey256Hex));
  if (!internal::IsBoringSsl()) {
    EXPECT_THAT(AesGcmSivBoringSsl::New(key).status(),
                StatusIs(absl::StatusCode::kUnimplemented));
  } else {
    util::StatusOr<std::unique_ptr<Aead>> aead = AesGcmSivBoringSsl::New(key);
    ASSERT_THAT(aead, IsOk());

    util::StatusOr<std::string> ciphertext =
        (*aead)->Encrypt(kMessage, kAssociatedData);
    ASSERT_THAT(ciphertext, IsOk());
    EXPECT_THAT(*ciphertext,
                SizeIs(kMessage.size() + kIvSizeInBytes + kTagSizeInBytes));
    util::StatusOr<std::string> plaintext =
        (*aead)->Decrypt(*ciphertext, kAssociatedData);
    ASSERT_THAT(plaintext, IsOk());
    EXPECT_EQ(*plaintext, kMessage);
  }
}

TEST(AesGcmSivBoringSslTest, DecryptFailsIfCiphertextTooSmall) {
  if (!internal::IsBoringSsl()) {
    GTEST_SKIP() << "Unimplemented with OpenSSL";
  }
  if (IsFipsModeEnabled()) {
    GTEST_SKIP() << "Not supported in FIPS-only mode";
  }

  util::SecretData key =
      util::SecretDataFromStringView(absl::HexStringToBytes(kKey256Hex));
  util::StatusOr<std::unique_ptr<Aead>> aead = AesGcmSivBoringSsl::New(key);
  ASSERT_THAT(aead, IsOk());

  for (int i = 1; i < kIvSizeInBytes + kTagSizeInBytes; i++) {
    std::string ciphertext;
    ResizeStringUninitialized(&ciphertext, i);
    EXPECT_THAT((*aead)->Decrypt(ciphertext, kAssociatedData).status(),
                StatusIs(absl::StatusCode::kInvalidArgument));
  }
}

TEST(AesGcmSivBoringSslTest, TestFipsOnly) {
  if (!internal::IsBoringSsl()) {
    GTEST_SKIP() << "Unimplemented with OpenSSL";
  }
  if (!IsFipsModeEnabled()) {
    GTEST_SKIP() << "Only supported in FIPS-only mode";
  }

  util::SecretData key128 = util::SecretDataFromStringView(
      absl::HexStringToBytes("000102030405060708090a0b0c0d0e0f"));
  util::SecretData key256 =
      util::SecretDataFromStringView(absl::HexStringToBytes(
          "000102030405060708090a0b0c0d0e0f000102030405060708090a0b0c0d0e0f"));

  EXPECT_THAT(AesGcmSivBoringSsl::New(key128).status(),
              StatusIs(absl::StatusCode::kInternal));
  EXPECT_THAT(AesGcmSivBoringSsl::New(key256).status(),
              StatusIs(absl::StatusCode::kInternal));
}

class AesGcmSivBoringSslWycheproofTest
    : public TestWithParam<internal::WycheproofTestVector> {
  void SetUp() override {
    if (!internal::IsBoringSsl()) {
      GTEST_SKIP() << "Unimplemented with OpenSSL";
    }
    if (IsFipsModeEnabled()) {
      GTEST_SKIP() << "Not supported in FIPS-only mode";
    }
    internal::WycheproofTestVector test_vector = GetParam();
    if ((test_vector.key.size() != 16 && test_vector.key.size() != 32) ||
        test_vector.nonce.size() != kIvSizeInBytes ||
        test_vector.tag.size() != kTagSizeInBytes) {
      GTEST_SKIP() << "Unsupported parameters: key size "
                   << test_vector.key.size()
                   << " nonce size: " << test_vector.nonce.size()
                   << " tag size: " << test_vector.tag.size();
    }
  }
};

TEST_P(AesGcmSivBoringSslWycheproofTest, Decrypt) {
  internal::WycheproofTestVector test_vector = GetParam();
  util::SecretData key = util::SecretDataFromStringView(test_vector.key);
  util::StatusOr<std::unique_ptr<Aead>> cipher = AesGcmSivBoringSsl::New(key);
  ASSERT_THAT(cipher, IsOk());
  std::string ciphertext =
      absl::StrCat(test_vector.nonce, test_vector.ct, test_vector.tag);
  util::StatusOr<std::string> plaintext =
      (*cipher)->Decrypt(ciphertext, test_vector.aad);
  if (plaintext.ok()) {
    EXPECT_NE(test_vector.expected, "invalid");
    EXPECT_EQ(*plaintext, test_vector.msg);
  } else {
    EXPECT_THAT(test_vector.expected, Not(AllOf(Eq("valid"), Eq("acceptable"))))
        << "Could not decrypt test with tcId: " << test_vector.id
        << " iv_size: " << test_vector.nonce.size()
        << " tag_size: " << test_vector.tag.size()
        << " key_size: " << key.size() << "; error: " << plaintext.status();
  }
}

INSTANTIATE_TEST_SUITE_P(AesGcmSivBoringSslWycheproofTests,
                         AesGcmSivBoringSslWycheproofTest,
                         ValuesIn(internal::ReadWycheproofTestVectors(
                             /*file_name=*/"aes_gcm_siv_test.json")));

}  // namespace
}  // namespace subtle
}  // namespace tink
}  // namespace crypto