////////////////////////////////////////////////////////////////////////////////
// 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 "common/crypto_util.h"

#include <string>

#include "testing/gmock.h"
#include "testing/gunit.h"
#include "absl/strings/escaping.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/string_view.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 key_data[] =
    { 0x87, 0x27, 0xa4, 0x0e, 0xbd, 0x82, 0x32, 0x9e,
      0x6b, 0x3b, 0x4e, 0x29, 0xfa, 0x3b, 0x00, 0x4b };

static std::string key_str(key_data, key_data + sizeof(key_data));

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

static std::string iv_str(iv_data, iv_data + sizeof(iv_data));

TEST(CryptoUtilTest, DeriveAes128KeyTest) {
  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 key_str(key_data, key_data + sizeof(key_data));
  std::string context_str(context, context + sizeof(context));
  std::string result = DeriveKey(key_str, label_str, context_str, 128);

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

  ASSERT_EQ(result, output_128);

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

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

  ASSERT_EQ(result, output_384);
}

TEST(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(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(key_str, message));

  ASSERT_EQ(signature.size(), 32);

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

TEST(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(), 32);

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

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

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

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

TEST(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(key_str, message));

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

TEST(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(20, signature.size());
  // Create valid signature to compare.
  signature = CreateSignatureHmacSha1(key_str, message);
  // Test with bogus key.
  ASSERT_FALSE(VerifySignatureHmacSha1(bogus_key, signature, message));
  // Test with munged signature.
  signature[0] = 0xFF;
  ASSERT_FALSE(VerifySignatureHmacSha1(key_str, signature, message));
  // Test with bogus signature.
  ASSERT_FALSE(VerifySignatureHmacSha1(key_str, "bogus", message));
}

TEST(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(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(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