//
// Copyright (C) 2010 The Android Open Source Project
//
// 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 "update_engine/payload_generator/payload_signer.h"

#include <string>
#include <vector>

#include <base/logging.h>
#include <base/stl_util.h>
#include <gtest/gtest.h>

#include "update_engine/common/hash_calculator.h"
#include "update_engine/common/test_utils.h"
#include "update_engine/common/utils.h"
#include "update_engine/payload_consumer/payload_constants.h"
#include "update_engine/payload_consumer/payload_verifier.h"
#include "update_engine/payload_generator/payload_file.h"
#include "update_engine/update_metadata.pb.h"

using chromeos_update_engine::test_utils::GetBuildArtifactsPath;
using std::string;
using std::vector;

// Note: the test key was generated with the following command:
// openssl genrsa -out unittest_key.pem 2048
// The public-key version is created by the build system.

namespace chromeos_update_engine {

const char* kUnittestPrivateKeyPath = "unittest_key.pem";
const char* kUnittestPublicKeyPath = "unittest_key.pub.pem";
const char* kUnittestPrivateKey2Path = "unittest_key2.pem";
const char* kUnittestPublicKey2Path = "unittest_key2.pub.pem";
const char* kUnittestPrivateKeyRSA4096Path = "unittest_key_RSA4096.pem";
const char* kUnittestPublicKeyRSA4096Path = "unittest_key_RSA4096.pub.pem";
const char* kUnittestPrivateKeyECPath = "unittest_key_EC.pem";
const char* kUnittestPublicKeyECPath = "unittest_key_EC.pub.pem";

// Some data and its corresponding hash and signature:
const char kDataToSign[] = "This is some data to sign.";

// Generated by:
// echo -n 'This is some data to sign.' | openssl dgst -sha256 -binary |
//   hexdump -v -e '" " 8/1 "0x%02x, " "\n"'
const uint8_t kDataHash[] = {0x7a, 0x07, 0xa6, 0x44, 0x08, 0x86, 0x20, 0xa6,
                             0xc1, 0xf8, 0xd9, 0x02, 0x05, 0x63, 0x0d, 0xb7,
                             0xfc, 0x2b, 0xa0, 0xa9, 0x7c, 0x9d, 0x1d, 0x8c,
                             0x01, 0xf5, 0x78, 0x6d, 0xc5, 0x11, 0xb4, 0x06};

// Generated with openssl 1.0, which at the time of this writing, you need
// to download and install yourself. Here's my command:
// echo -n 'This is some data to sign.' | openssl dgst -sha256 -binary |
//    ~/local/bin/openssl pkeyutl -sign -inkey unittest_key.pem -pkeyopt
//    digest:sha256 | hexdump -v -e '" " 8/1 "0x%02x, " "\n"'
const uint8_t kDataSignature[] = {
    0x9f, 0x86, 0x25, 0x8b, 0xf3, 0xcc, 0xe3, 0x95, 0x5f, 0x45, 0x83, 0xb2,
    0x66, 0xf0, 0x2a, 0xcf, 0xb7, 0xaa, 0x52, 0x25, 0x7a, 0xdd, 0x9d, 0x65,
    0xe5, 0xd6, 0x02, 0x4b, 0x37, 0x99, 0x53, 0x06, 0xc2, 0xc9, 0x37, 0x36,
    0x25, 0x62, 0x09, 0x4f, 0x6b, 0x22, 0xf8, 0xb3, 0x89, 0x14, 0x98, 0x1a,
    0xbc, 0x30, 0x90, 0x4a, 0x43, 0xf5, 0xea, 0x2e, 0xf0, 0xa4, 0xba, 0xc3,
    0xa7, 0xa3, 0x44, 0x70, 0xd6, 0xc4, 0x89, 0xd8, 0x45, 0x71, 0xbb, 0xee,
    0x59, 0x87, 0x3d, 0xd5, 0xe5, 0x40, 0x22, 0x3d, 0x73, 0x7e, 0x2a, 0x58,
    0x93, 0x8e, 0xcb, 0x9c, 0xf2, 0xbb, 0x4a, 0xc9, 0xd2, 0x2c, 0x52, 0x42,
    0xb0, 0xd1, 0x13, 0x22, 0xa4, 0x78, 0xc7, 0xc6, 0x3e, 0xf1, 0xdc, 0x4c,
    0x7b, 0x2d, 0x40, 0xda, 0x58, 0xac, 0x4a, 0x11, 0x96, 0x3d, 0xa0, 0x01,
    0xf6, 0x96, 0x74, 0xf6, 0x6c, 0x0c, 0x49, 0x69, 0x4e, 0xc1, 0x7e, 0x9f,
    0x2a, 0x42, 0xdd, 0x15, 0x6b, 0x37, 0x2e, 0x3a, 0xa7, 0xa7, 0x6d, 0x91,
    0x13, 0xe8, 0x59, 0xde, 0xfe, 0x99, 0x07, 0xd9, 0x34, 0x0f, 0x17, 0xb3,
    0x05, 0x4c, 0xd2, 0xc6, 0x82, 0xb7, 0x38, 0x36, 0x63, 0x1d, 0x9e, 0x21,
    0xa6, 0x32, 0xef, 0xf1, 0x65, 0xe6, 0xed, 0x95, 0x25, 0x9b, 0x61, 0xe0,
    0xba, 0x86, 0xa1, 0x7f, 0xf8, 0xa5, 0x4a, 0x32, 0x1f, 0x15, 0x20, 0x8a,
    0x41, 0xc5, 0xb0, 0xd9, 0x4a, 0xda, 0x85, 0xf3, 0xdc, 0xa0, 0x98, 0x5d,
    0x1d, 0x18, 0x9d, 0x2e, 0x42, 0xea, 0x69, 0x13, 0x74, 0x3c, 0x74, 0xf7,
    0x6d, 0x43, 0xb0, 0x63, 0x90, 0xdb, 0x04, 0xd5, 0x05, 0xc9, 0x73, 0x1f,
    0x6c, 0xd6, 0xfa, 0x46, 0x4e, 0x0f, 0x33, 0x58, 0x5b, 0x0d, 0x1b, 0x55,
    0x39, 0xb9, 0x0f, 0x43, 0x37, 0xc0, 0x06, 0x0c, 0x29, 0x93, 0x43, 0xc7,
    0x43, 0xb9, 0xab, 0x7d};

namespace {
void SignSampleData(string* out_signature, const vector<string>& private_keys) {
  uint64_t length = 0;
  EXPECT_TRUE(PayloadSigner::SignatureBlobLength(private_keys, &length));
  EXPECT_GT(length, 0U);
  brillo::Blob hash_blob;
  EXPECT_TRUE(HashCalculator::RawHashOfBytes(
      kDataToSign, strlen(kDataToSign), &hash_blob));
  EXPECT_TRUE(
      PayloadSigner::SignHashWithKeys(hash_blob, private_keys, out_signature));
  EXPECT_EQ(length, out_signature->size());
}
}  // namespace

class PayloadSignerTest : public ::testing::Test {
 protected:
  brillo::Blob hash_data_{std::begin(kDataHash), std::end(kDataHash)};
};

TEST_F(PayloadSignerTest, SignSimpleTextTest) {
  string signature;
  SignSampleData(&signature, {GetBuildArtifactsPath(kUnittestPrivateKeyPath)});

  // Check the signature itself
  Signatures signatures;
  EXPECT_TRUE(signatures.ParseFromString(signature));
  EXPECT_EQ(1, signatures.signatures_size());
  const Signatures::Signature& sig = signatures.signatures(0);
  const string& sig_data = sig.data();
  ASSERT_EQ(base::size(kDataSignature), sig_data.size());
  for (size_t i = 0; i < base::size(kDataSignature); i++) {
    EXPECT_EQ(kDataSignature[i], static_cast<uint8_t>(sig_data[i]));
  }
}

TEST_F(PayloadSignerTest, VerifyAllSignatureTest) {
  string signature;
  SignSampleData(&signature,
                 {GetBuildArtifactsPath(kUnittestPrivateKeyPath),
                  GetBuildArtifactsPath(kUnittestPrivateKey2Path),
                  GetBuildArtifactsPath(kUnittestPrivateKeyRSA4096Path),
                  GetBuildArtifactsPath(kUnittestPrivateKeyECPath)});

  // Either public key should pass the verification.
  for (const auto& path : {kUnittestPublicKeyPath,
                           kUnittestPublicKey2Path,
                           kUnittestPublicKeyRSA4096Path,
                           kUnittestPublicKeyECPath}) {
    string public_key;
    EXPECT_TRUE(utils::ReadFile(GetBuildArtifactsPath(path), &public_key));
    auto payload_verifier = PayloadVerifier::CreateInstance(public_key);
    EXPECT_TRUE(payload_verifier != nullptr);
    EXPECT_TRUE(payload_verifier->VerifySignature(signature, hash_data_));
  }
}

TEST_F(PayloadSignerTest, VerifySignatureTest) {
  string signature;
  SignSampleData(&signature, {GetBuildArtifactsPath(kUnittestPrivateKeyPath)});

  string public_key;
  EXPECT_TRUE(utils::ReadFile(GetBuildArtifactsPath(kUnittestPublicKeyPath),
                              &public_key));
  auto payload_verifier = PayloadVerifier::CreateInstance(public_key);
  EXPECT_TRUE(payload_verifier != nullptr);
  EXPECT_TRUE(payload_verifier->VerifySignature(signature, hash_data_));

  // Passing the invalid key should fail the verification.
  public_key.clear();
  EXPECT_TRUE(utils::ReadFile(GetBuildArtifactsPath(kUnittestPublicKey2Path),
                              &public_key));
  payload_verifier = PayloadVerifier::CreateInstance(public_key);
  EXPECT_TRUE(payload_verifier != nullptr);
  EXPECT_FALSE(payload_verifier->VerifySignature(signature, hash_data_));
}

TEST_F(PayloadSignerTest, SkipMetadataSignatureTest) {
  ScopedTempFile payload_file("payload.XXXXXX");
  PayloadGenerationConfig config;
  config.version.major = kBrilloMajorPayloadVersion;
  PayloadFile payload;
  EXPECT_TRUE(payload.Init(config));
  uint64_t metadata_size;
  EXPECT_TRUE(payload.WritePayload(
      payload_file.path(), "/dev/null", "", &metadata_size));
  const vector<size_t> sizes = {256};
  brillo::Blob unsigned_payload_hash, unsigned_metadata_hash;
  EXPECT_TRUE(PayloadSigner::HashPayloadForSigning(payload_file.path(),
                                                   sizes,
                                                   &unsigned_payload_hash,
                                                   &unsigned_metadata_hash));
  EXPECT_TRUE(
      payload.WritePayload(payload_file.path(),
                           "/dev/null",
                           GetBuildArtifactsPath(kUnittestPrivateKeyPath),
                           &metadata_size));
  brillo::Blob signed_payload_hash, signed_metadata_hash;
  EXPECT_TRUE(PayloadSigner::HashPayloadForSigning(
      payload_file.path(), sizes, &signed_payload_hash, &signed_metadata_hash));
  EXPECT_EQ(unsigned_payload_hash, signed_payload_hash);
  EXPECT_EQ(unsigned_metadata_hash, signed_metadata_hash);
}

TEST_F(PayloadSignerTest, VerifySignedPayloadTest) {
  ScopedTempFile payload_file("payload.XXXXXX");
  PayloadGenerationConfig config;
  config.version.major = kBrilloMajorPayloadVersion;
  PayloadFile payload;
  EXPECT_TRUE(payload.Init(config));
  uint64_t metadata_size;
  EXPECT_TRUE(
      payload.WritePayload(payload_file.path(),
                           "/dev/null",
                           GetBuildArtifactsPath(kUnittestPrivateKeyPath),
                           &metadata_size));
  EXPECT_TRUE(PayloadSigner::VerifySignedPayload(
      payload_file.path(), GetBuildArtifactsPath(kUnittestPublicKeyPath)));
}

}  // namespace chromeos_update_engine
