////////////////////////////////////////////////////////////////////////////////
// Copyright 2016 Google LLC.
//
// This software is licensed under the terms defined in the Widevine Master
// License Agreement. For a copy of this agreement, please contact
// widevine-licensing@google.com.
////////////////////////////////////////////////////////////////////////////////

// Unit tests for the crypto_util helper functions.

#include "crypto_utils/crypto_util.h"

#include <string>

#include "absl/strings/escaping.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/string_view.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "third_party/boringssl/src/include/openssl/aes.h"

namespace widevine {
namespace crypto_util {
const char kCENCStr[] = "cenc";
const char kCBC1Str[] = "cbc1";
const char kCENSStr[] = "cens";
const char kCBCSStr[] = "cbcs";

static unsigned char kAes128KeyData[] = {0x87, 0x27, 0xa4, 0x0e, 0xbd, 0x82,
                                         0x32, 0x9e, 0x6b, 0x3b, 0x4e, 0x29,
                                         0xfa, 0x3b, 0x00, 0x4b};

static unsigned char kAes256KeyData[] = {
    0x87, 0x27, 0xa4, 0x0e, 0xbd, 0x82, 0x32, 0x9e, 0x6b, 0x3b, 0x4e,
    0x29, 0xfa, 0x3b, 0x00, 0x4b, 0x87, 0x27, 0xa4, 0x0e, 0xbd, 0x82,
    0x32, 0x9e, 0x6b, 0x3b, 0x4e, 0x29, 0xfa, 0x3b, 0x00, 0x4b};

static unsigned char kAes128IvData[] = {0x00, 0x01, 0x02, 0x03, 0x04, 0x05,
                                        0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
                                        0x0c, 0x0d, 0x0e, 0x0f};

class CryptoUtilTest : public ::testing::Test {
 public:
  CryptoUtilTest()
      : aes_128_key_(kAes128KeyData, kAes128KeyData + sizeof(kAes128KeyData)),
        aes_256_key_(kAes256KeyData, kAes256KeyData + sizeof(kAes256KeyData)),
        iv_128_(kAes128IvData, kAes128IvData + sizeof(kAes128IvData)) {}

 protected:
  std::string aes_128_key_;
  std::string aes_256_key_;
  std::string iv_128_;
};

TEST_F(CryptoUtilTest, DeriveAes128MasterKeyTest) {
  unsigned char label[] = {0x16, 0xf1, 0xa4, 0x32, 0x9f, 0x94, 0x55, 0xc1, 0x92,
                           0xa0, 0x34, 0x8a, 0x8b, 0x6b, 0x77, 0x08, 0xbc, 0x23,
                           0x70, 0x16, 0xbc, 0xda, 0xfb, 0x60, 0xd1, 0xcf, 0x6a,
                           0x4d, 0x40, 0xa1, 0xe3, 0xfe, 0xd3, 0xe9, 0xa6, 0x58,
                           0x4c, 0xd4, 0xad, 0xa4, 0xa2};

  unsigned char context[] = {0x4c, 0x53, 0xc0, 0xe9, 0x9e, 0x7f, 0x7d,
                             0x6d, 0x0a, 0x76, 0x7c, 0xc7, 0x25, 0xb5,
                             0x5b, 0x80, 0x81, 0x91, 0xff};

  unsigned char output0[] = {0xd5, 0xad, 0x2d, 0xb1, 0x5a, 0x06, 0xcb, 0x50,
                             0xf2, 0x59, 0x5a, 0xb2, 0xb2, 0x0d, 0x44, 0x4e};

  unsigned char output1[] = {
      0xdf, 0x38, 0x45, 0x97, 0x5d, 0x7a, 0x81, 0xb4, 0x94, 0x86, 0xaf, 0x0c,
      0xdc, 0x4d, 0xeb, 0x62, 0x31, 0x39, 0x67, 0x8f, 0xff, 0x5d, 0x68, 0x35,
      0xdc, 0x89, 0x5f, 0x47, 0xca, 0xe0, 0x2d, 0x3a, 0x10, 0x24, 0xf8, 0x7e,
      0x5b, 0x70, 0xe1, 0xa3, 0x4a, 0x47, 0x2f, 0x04, 0xe0, 0x34, 0x75, 0x22};

  std::string label_str(label, label + sizeof(label));
  std::string context_str(context, context + sizeof(context));
  std::string result = DeriveKey(aes_128_key_, label_str, context_str, 128);

  std::string output_128(output0, output0 + sizeof(output0));

  ASSERT_EQ(result, output_128);

  result = DeriveKey(aes_128_key_, label_str, context_str, 384);

  std::string output_384(output1, output1 + sizeof(output1));

  ASSERT_EQ(result, output_384);
}

TEST_F(CryptoUtilTest, DeriveAes256MasterKeyTest) {
  const unsigned char label[] = {
      0x16, 0xf1, 0xa4, 0x32, 0x9f, 0x94, 0x55, 0xc1, 0x92, 0xa0, 0x34,
      0x8a, 0x8b, 0x6b, 0x77, 0x08, 0xbc, 0x23, 0x70, 0x16, 0xbc, 0xda,
      0xfb, 0x60, 0xd1, 0xcf, 0x6a, 0x4d, 0x40, 0xa1, 0xe3, 0xfe, 0xd3,
      0xe9, 0xa6, 0x58, 0x4c, 0xd4, 0xad, 0xa4, 0xa2};

  const unsigned char context[] = {0x4c, 0x53, 0xc0, 0xe9, 0x9e, 0x7f, 0x7d,
                                   0x6d, 0x0a, 0x76, 0x7c, 0xc7, 0x25, 0xb5,
                                   0x5b, 0x80, 0x81, 0x91, 0xff};

  const unsigned char expected_128[] = {0x76, 0x36, 0x33, 0x0e, 0x0b, 0x2c,
                                        0x38, 0xc2, 0x9e, 0x53, 0x23, 0x8d,
                                        0x2e, 0xc6, 0x3a, 0x46};

  const std::string label_str(label, label + sizeof(label));
  const std::string context_str(context, context + sizeof(context));
  std::string result = DeriveKey(aes_256_key_, label_str, context_str, 128);
  EXPECT_EQ(std::string(expected_128, expected_128 + sizeof(expected_128)),
            result)
      << ::absl::BytesToHexString(result);

  const unsigned char expected_256[] = {
      0xfb, 0x8f, 0xdf, 0x0e, 0x22, 0xfe, 0xf7, 0x2b, 0xd1, 0x9a, 0x1d,
      0xd2, 0xcb, 0xb0, 0x11, 0x5c, 0x6c, 0xa7, 0xe1, 0x7f, 0x72, 0xce,
      0x3a, 0x60, 0x34, 0x89, 0x6d, 0x08, 0xef, 0xde, 0x19, 0x45};
  result = DeriveKey(aes_256_key_, label_str, context_str, 256);
  EXPECT_EQ(std::string(expected_256, expected_256 + sizeof(expected_256)),
            result)
      << ::absl::BytesToHexString(result);

  const unsigned char expected_384[] = {
      0x65, 0xbc, 0xe3, 0xf3, 0xfb, 0xfa, 0xce, 0x1d, 0x24, 0x63, 0x9c, 0x8f,
      0x48, 0x0e, 0xbd, 0x76, 0xd1, 0x14, 0x0b, 0xb1, 0x3a, 0x3d, 0x6e, 0x30,
      0xa9, 0xf4, 0x40, 0x35, 0x0d, 0x6b, 0xc5, 0x1e, 0x9c, 0xa9, 0x5f, 0xf9,
      0xde, 0x96, 0xa0, 0xa4, 0x22, 0x62, 0x21, 0xc5, 0xd6, 0xd4, 0xf4, 0x6f};
  result = DeriveKey(aes_256_key_, label_str, context_str, 384);
  EXPECT_EQ(std::string(expected_384, expected_384 + sizeof(expected_384)),
            result)
      << ::absl::BytesToHexString(result);
}

TEST_F(CryptoUtilTest, DeriveAesInvalidSizeModulus) {
  // This is the control case that we correctly derive 128 bits.
  EXPECT_NE("", DeriveKey(aes_128_key_, "foo", "bar", 128));
  EXPECT_EQ("", DeriveKey(aes_128_key_, "foo", "bar", 127));
}

TEST_F(CryptoUtilTest, DeriveAesMaxBlocks) {
  EXPECT_EQ(
      255u * AES_BLOCK_SIZE,
      DeriveKey(aes_128_key_, "foo", "bar", AES_BLOCK_SIZE * 8 * 255).size());
}

TEST_F(CryptoUtilTest, DeriveAesTooManyBlocks) {
  EXPECT_EQ("",
            DeriveKey(aes_128_key_, "foo", "bar", AES_BLOCK_SIZE * 8 * 256));
}

TEST_F(CryptoUtilTest, DeriveAes128InvalidKeySize) {
  EXPECT_EQ("", DeriveKey(aes_128_key_.substr(0, 15), "foo", "bar", 128));
}

TEST_F(CryptoUtilTest, DeriveAes256InvalidKeySize) {
  EXPECT_EQ("", DeriveKey(aes_256_key_.substr(0, 31), "foo", "bar", 128));
}

TEST_F(CryptoUtilTest, DeriveGroupSesionKey) {
  unsigned char output[] = {0x92, 0x6c, 0x2f, 0x5,  0xa6, 0x4f, 0xff, 0xb1,
                            0x86, 0x4a, 0x1a, 0x14, 0x95, 0xeb, 0xb0, 0xf1};
  std::string group_session_key = DeriveGroupSessionKey("test_group_id", 128);
  EXPECT_EQ(crypto_util::kAes128KeySizeBytes, group_session_key.size());
  const std::string output_128(output, output + sizeof(output));
  ASSERT_EQ(output_128, group_session_key);
}

TEST_F(CryptoUtilTest, TestCreateAndVerifySignatureHmacSha256) {
  unsigned char message_data[] = {
      0xd9, 0x24, 0x2d, 0x03, 0x93, 0x6f, 0x22, 0x53, 0x99, 0x7a, 0x7d,
      0x9b, 0x0c, 0xcf, 0xfd, 0xb2, 0x66, 0x0d, 0xaf, 0xdb, 0xa2, 0xad,
      0x23, 0x91, 0x8a, 0xdf, 0x01, 0x80, 0xa3, 0x35, 0xf9, 0xde, 0xf6,
      0x5b, 0xa2, 0x85, 0x0e, 0x2d, 0x93, 0x6f, 0x99, 0x7a, 0x63, 0x47,
      0x2e, 0x54, 0x35, 0xb5, 0xf7, 0x45, 0xed, 0x6b, 0xcf, 0xe8, 0xf2,
      0x54, 0x97, 0x69, 0x23, 0x74, 0x34, 0x9a, 0x34, 0xda};

  std::string message(message_data, message_data + sizeof(message_data));
  std::string signature(CreateSignatureHmacSha256(aes_128_key_, message));

  ASSERT_EQ(signature.size(), 32u);

  ASSERT_TRUE(VerifySignatureHmacSha256(aes_128_key_, signature, message));
}

TEST_F(CryptoUtilTest, TestFailCreateAndVerifyHmacSha256) {
  unsigned char message_data[] = {
      0xd9, 0x24, 0x2d, 0x03, 0x93, 0x6f, 0x22, 0x53, 0x99, 0x7a, 0x7d,
      0x9b, 0x0c, 0xcf, 0xfd, 0xb2, 0x66, 0x0d, 0xaf, 0xdb, 0xa2, 0xad,
      0x23, 0x91, 0x8a, 0xdf, 0x01, 0x80, 0xa3, 0x35, 0xf9, 0xde, 0xf6,
      0x5b, 0xa2, 0x85, 0x0e, 0x2d, 0x93, 0x6f, 0x99, 0x7a, 0x63, 0x47,
      0x2e, 0x54, 0x35, 0xb5, 0xf7, 0x45, 0xed, 0x6b, 0xcf, 0xe8, 0xf2,
      0x54, 0x97, 0x69, 0x23, 0x74, 0x34, 0x9a, 0x34, 0xda};

  std::string message(message_data, message_data + sizeof(message_data));
  // Test with bogus key;
  std::string bogus_key("bogus");
  std::string signature(CreateSignatureHmacSha256(bogus_key, message));

  // This should still produce an hmac signature.
  ASSERT_EQ(signature.size(), 32u);

  // Create valid signature to compare.
  signature = CreateSignatureHmacSha256(aes_128_key_, message);

  // Test with bogus key.
  ASSERT_FALSE(VerifySignatureHmacSha256(bogus_key, signature, message));

  // Test with munged signature.
  signature[0] = 0xFF;
  ASSERT_FALSE(VerifySignatureHmacSha256(aes_128_key_, signature, message));

  // Test with bogus signature.
  ASSERT_FALSE(VerifySignatureHmacSha256(aes_128_key_, "bogus", message));
}

TEST_F(CryptoUtilTest, TestCreateAndVerifySignatureHmacSha1) {
  unsigned char message_data[] = {
      0xd9, 0x24, 0x2d, 0x03, 0x93, 0x6f, 0x22, 0x53, 0x99, 0x7a, 0x7d,
      0x9b, 0x0c, 0xcf, 0xfd, 0xb2, 0x66, 0x0d, 0xaf, 0xdb, 0xa2, 0xad,
      0x23, 0x91, 0x8a, 0xdf, 0x01, 0x80, 0xa3, 0x35, 0xf9, 0xde, 0xf6,
      0x5b, 0xa2, 0x85, 0x0e, 0x2d, 0x93, 0x6f, 0x99, 0x7a, 0x63, 0x47,
      0x2e, 0x54, 0x35, 0xb5, 0xf7, 0x45, 0xed, 0x6b, 0xcf, 0xe8, 0xf2,
      0x54, 0x97, 0x69, 0x23, 0x74, 0x34, 0x9a, 0x34, 0xda};

  std::string message(message_data, message_data + sizeof(message_data));
  std::string signature(CreateSignatureHmacSha1(aes_128_key_, message));

  ASSERT_EQ(20u, signature.size());
  ASSERT_TRUE(VerifySignatureHmacSha1(aes_128_key_, signature, message));
}

TEST_F(CryptoUtilTest, TestFailCreateAndVerifyHmacSha1) {
  unsigned char message_data[] = {
      0xd9, 0x24, 0x2d, 0x03, 0x93, 0x6f, 0x22, 0x53, 0x99, 0x7a, 0x7d,
      0x9b, 0x0c, 0xcf, 0xfd, 0xb2, 0x66, 0x0d, 0xaf, 0xdb, 0xa2, 0xad,
      0x23, 0x91, 0x8a, 0xdf, 0x01, 0x80, 0xa3, 0x35, 0xf9, 0xde, 0xf6,
      0x5b, 0xa2, 0x85, 0x0e, 0x2d, 0x93, 0x6f, 0x99, 0x7a, 0x63, 0x47,
      0x2e, 0x54, 0x35, 0xb5, 0xf7, 0x45, 0xed, 0x6b, 0xcf, 0xe8, 0xf2,
      0x54, 0x97, 0x69, 0x23, 0x74, 0x34, 0x9a, 0x34, 0xda};

  std::string message(message_data, message_data + sizeof(message_data));
  // Test with bogus key;
  std::string bogus_key("bogus");
  std::string signature(CreateSignatureHmacSha1(bogus_key, message));

  // This should still produce an hmac signature.
  ASSERT_EQ(20u, signature.size());
  // Create valid signature to compare.
  signature = CreateSignatureHmacSha1(aes_128_key_, message);
  // Test with bogus key.
  ASSERT_FALSE(VerifySignatureHmacSha1(bogus_key, signature, message));
  // Test with munged signature.
  signature[0] = 0xFF;
  ASSERT_FALSE(VerifySignatureHmacSha1(aes_128_key_, signature, message));
  // Test with bogus signature.
  ASSERT_FALSE(VerifySignatureHmacSha1(aes_128_key_, "bogus", message));
}

TEST_F(CryptoUtilTest, DeriveIv) {
  // First value in the pair is the key_id, second value is the expected IV.
  std::pair<std::string, std::string> id_iv_pairs[] = {
      {"1234567890123456", "3278234c7682d1a2e153af4912975f5f"},
      {"0987654321098765", "cf09abd30f04b60544910791a6b904cf"}};
  for (const auto& id_iv_pair : id_iv_pairs) {
    SCOPED_TRACE(::absl::StrCat("test case:", id_iv_pair.first));
    EXPECT_EQ(id_iv_pair.second,
              ::absl::BytesToHexString(DeriveIv(id_iv_pair.first)));
    // Repeat same call to verify derivied result is repeatable.
    EXPECT_EQ(id_iv_pair.second,
              ::absl::BytesToHexString(DeriveIv(id_iv_pair.first)));
  }
}

TEST_F(CryptoUtilTest, DeriveKeyId) {
  // First value in the pair is the context, second value is the expected id.
  std::pair<std::string, std::string> context_id_pairs[] = {
      {"1234567890123456", "a3c4a8c0d0e24e96f38f492254186a9d"},
      {"0987654321098765", "084fc6bece9688ccce6b1672d9b47e22"}};
  for (const auto& context_id_pair : context_id_pairs) {
    SCOPED_TRACE(::absl::StrCat("test case:", context_id_pair.first));
    EXPECT_EQ(context_id_pair.second,
              ::absl::BytesToHexString(DeriveKeyId(context_id_pair.first)));
    // Repeat same call to verify derivied result is repeatable.
    EXPECT_EQ(context_id_pair.second,
              ::absl::BytesToHexString(DeriveKeyId(context_id_pair.first)));
  }
}

TEST_F(CryptoUtilTest, Verify4CCEncryptionIDFromBadString) {
  uint32_t cc_code;
  ASSERT_FALSE(FourCCEncryptionSchemeIDFromString("garbage", &cc_code));
  ASSERT_FALSE(FourCCEncryptionSchemeIDFromString("junk", &cc_code));
  ASSERT_FALSE(FourCCEncryptionSchemeIDFromString("cencc", &cc_code));
}

TEST_F(CryptoUtilTest, Verify4CCEncryptionIDFromString) {
  uint32_t cc_code = 0;
  ASSERT_TRUE(FourCCEncryptionSchemeIDFromString(kCENCStr, &cc_code));
  ASSERT_EQ(kCENCSchemeID, cc_code);
  ASSERT_TRUE(FourCCEncryptionSchemeIDFromString(kCBC1Str, &cc_code));
  ASSERT_EQ(kCBC1SchemeID, cc_code);
  ASSERT_TRUE(FourCCEncryptionSchemeIDFromString(kCENSStr, &cc_code));
  ASSERT_EQ(kCENSSchemeID, cc_code);
  ASSERT_TRUE(FourCCEncryptionSchemeIDFromString(kCBCSStr, &cc_code));
  ASSERT_EQ(kCBCSSchemeID, cc_code);
}

}  // namespace crypto_util
}  // namespace widevine