android/libwvdrmengine/oemcrypto/test/oemcrypto_basic_test.cpp

// Copyright 2022 Google LLC. All Rights Reserved. This file and proprietary
// source code may only be used and distributed under the Widevine
// License Agreement.
//

#include "oemcrypto_basic_test.h"

#include "clock.h"
#include "jsmn.h"
#include "log.h"
#include "oemcrypto_corpus_generator_helper.h"
#include "oemcrypto_resource_test.h"
#include "test_sleep.h"

namespace wvoec {
void OEMCryptoClientTest::SetUp() {
  ::testing::Test::SetUp();
  wvutil::TestSleep::SyncFakeClock();
  const ::testing::TestInfo* const test_info =
      ::testing::UnitTest::GetInstance()->current_test_info();
  LOGD("Running test %s.%s", test_info->test_case_name(), test_info->name());
  OEMCrypto_SetSandbox(kTestSandbox, sizeof(kTestSandbox));
  ASSERT_EQ(OEMCrypto_SUCCESS, OEMCrypto_Initialize());
  const OEMCryptoResult api_status = OEMCrypto_SetMaxAPIVersion(kCurrentAPI);
  OEMCrypto_EnterTestMode();
  if (api_status != OEMCrypto_SUCCESS &&
      api_status != OEMCrypto_ERROR_NOT_IMPLEMENTED) {
    // Log error, but continue assuming no error.
    LOGE("OEMCrypto_SetMaxAPIVersion returned %d", api_status);
  }
}

void OEMCryptoClientTest::TearDown() {
  OEMCrypto_Terminate();
  ::testing::Test::TearDown();
}

const uint8_t* OEMCryptoClientTest::find(const vector<uint8_t>& message,
                                         const vector<uint8_t>& substring) {
  vector<uint8_t>::const_iterator pos = search(
      message.begin(), message.end(), substring.begin(), substring.end());
  if (pos == message.end()) {
    return nullptr;
  }
  return &(*pos);
}

OEMCryptoResult OEMCryptoClientTest::CopyBuffer(
    OEMCrypto_SESSION session, OEMCrypto_SharedMemory* input_buffer,
    size_t input_buffer_size,
    const OEMCrypto_DestBufferDesc* dest_buffer_descriptor,
    uint8_t subsample_flags) {
  if (ShouldGenerateCorpus() && input_buffer != nullptr &&
      dest_buffer_descriptor != nullptr) {
    const std::string file_name =
        GetFileName("oemcrypto_copy_buffer_fuzz_seed_corpus");

    OEMCrypto_Copy_Buffer_Fuzz fuzzed_structure;
    fuzzed_structure.dest_buffer_desc.type = dest_buffer_descriptor->type;
    switch (fuzzed_structure.dest_buffer_desc.type) {
      case OEMCrypto_BufferType_Clear:
        fuzzed_structure.dest_buffer_desc.buffer_config =
            dest_buffer_descriptor->buffer.clear.clear_buffer_length;
        break;

      case OEMCrypto_BufferType_Secure:
        fuzzed_structure.dest_buffer_desc.buffer_config =
            dest_buffer_descriptor->buffer.secure.secure_buffer_length;
        break;

      case OEMCrypto_BufferType_Direct:
        fuzzed_structure.dest_buffer_desc.buffer_config =
            dest_buffer_descriptor->buffer.direct.is_video;
        break;
    }
    fuzzed_structure.subsample_flags = subsample_flags;

    // Corpus for copy buffer fuzzer should be in the format:
    // (dest_buffer_descriptor | subsample_flags | input_buffer).
    AppendToFile(file_name, reinterpret_cast<const char*>(&fuzzed_structure),
                 sizeof(fuzzed_structure));
    AppendToFile(file_name, reinterpret_cast<const char*>(&input_buffer),
                 input_buffer_size);
  }
  return OEMCrypto_CopyBuffer(session, input_buffer, input_buffer_size,
                              dest_buffer_descriptor, subsample_flags);
}

const char* HDCPCapabilityAsString(OEMCrypto_HDCP_Capability value) {
  switch (value) {
    case HDCP_NONE:
      return "No HDCP supported, no secure data path";
    case HDCP_V1:
      return "HDCP version 1.x";
    case HDCP_V1_0:
      return "HDCP version 1.0";
    case HDCP_V1_1:
      return "HDCP version 1.1";
    case HDCP_V1_2:
      return "HDCP version 1.2";
    case HDCP_V1_3:
      return "HDCP version 1.3";
    case HDCP_V1_4:
      return "HDCP version 1.4";
    case HDCP_V2:
      return "HDCP version 2.0";
    case HDCP_V2_1:
      return "HDCP version 2.1";
    case HDCP_V2_2:
      return "HDCP version 2.2";
    case HDCP_V2_3:
      return "HDCP version 2.3";
    case HDCP_NO_DIGITAL_OUTPUT:
      return "No HDCP device attached/using local display with secure path";
    default:
      return "<INVALID VALUE>";
  }
}

// Return a printable string from data. If all the characters are printable,
// then just use the string. Otherwise, convert to hex.
std::string MaybeHex(const uint8_t* data, size_t length) {
  // Check for a early null termination. This is common for the device
  // id in a keybox, which is padded with 0s.
  const size_t c_len = strnlen(reinterpret_cast<const char*>(data), length);
  // If there is any nonzero after the first zero, then just use hex.
  for (size_t i = c_len; i < length; i++) {
    if (data[i] != 0) return "0x" + wvutil::HexEncode(data, length);
  }
  for (size_t i = 0; i < c_len; i++) {
    if (!isprint(data[i])) return "0x" + wvutil::HexEncode(data, length);
  }
  return std::string(reinterpret_cast<const char*>(data), c_len);
}

std::string MaybeHex(const std::vector<uint8_t>& data) {
  return MaybeHex(data.data(), data.size());
}

// Get the Device's ID and return it in a printable format.
std::string GetDeviceId() {
  OEMCryptoResult sts;
  std::vector<uint8_t> dev_id(128, 0);
  size_t dev_id_len = dev_id.size();
  sts = OEMCrypto_GetDeviceID(dev_id.data(), &dev_id_len);
  if (sts == OEMCrypto_ERROR_SHORT_BUFFER) {
    if (dev_id_len <= 0) return "NO DEVICE ID";
    dev_id.resize(dev_id_len);
    sts = OEMCrypto_GetDeviceID(dev_id.data(), &dev_id_len);
  }
  if (sts != OEMCrypto_SUCCESS) return "NO DEVICE ID";
  dev_id.resize(dev_id_len);
  return MaybeHex(dev_id);
}

/// @addtogroup basic
/// @{

TEST_F(OEMCryptoClientTest, FreeUnallocatedSecureBufferNoFailure) {
  Session s;
  s.open();
  OEMCrypto_DestBufferDesc output_descriptor;
  int secure_fd = kHugeRandomNumber;
  ASSERT_NE(OEMCrypto_SUCCESS,
            OEMCrypto_FreeSecureBuffer(s.session_id(), &output_descriptor,
                                       secure_fd));
  s.close();
}

/**
 *  Verifies initialization and logs version information.
 *  This test is first, because it might give an idea why other
 *  tests are failing when the device has the wrong keybox installed.
 *
 * The log message should be updated by Widevine with every release so that it
 * is easier to verify which version of the tests a partner is running. Widevine
 * should change the API version number when the API changes, but the unit tests
 * might be updated more frequently, and are only tracked by the date of the
 * last change.
 */
TEST_F(OEMCryptoClientTest, VersionNumber) {
  const std::string log_message =
      "OEMCrypto unit tests for API 18.4. Tests last updated 2023-08-03";
  cout << "             " << log_message << "\n";
  cout << "             "
       << "These tests are part of Android U."
       << "\n";
  LOGI("%s", log_message.c_str());
  // If any of the following fail, then it is time to update the log message
  // above.
  EXPECT_EQ(ODK_MAJOR_VERSION, 18);
  EXPECT_EQ(ODK_MINOR_VERSION, 4);
  EXPECT_EQ(kCurrentAPI, static_cast<unsigned>(ODK_MAJOR_VERSION));
  OEMCrypto_Security_Level level = OEMCrypto_SecurityLevel();
  EXPECT_GT(level, OEMCrypto_Level_Unknown);
  EXPECT_LE(level, OEMCrypto_Level3);
  cout << "             OEMCrypto Security Level is L" << level << endl;
  uint32_t version = OEMCrypto_APIVersion();
  uint32_t minor_version = OEMCrypto_MinorAPIVersion();
  cout << "             OEMCrypto API version is " << version << "."
       << minor_version << endl;
  cout << "             OEMCrypto Device ID is '" << GetDeviceId() << "'"
       << endl;

  if (OEMCrypto_SupportsUsageTable()) {
    cout << "             OEMCrypto supports usage tables" << endl;
  } else {
    cout << "             OEMCrypto does not support usage tables" << endl;
  }
  if (version >= 15) {
    const uint32_t tier = OEMCrypto_ResourceRatingTier();
    cout << "             Resource Rating Tier: " << tier << endl;
  }
  if (version >= 17) {
    OEMCryptoResult sts = OEMCrypto_ProductionReady();
    if (sts != OEMCrypto_SUCCESS) {
      LOGW("Device is not production ready, returns %d", sts);
    }
    std::string build_info;
    size_t buf_length = 0;
    sts = OEMCrypto_BuildInformation(&build_info[0], &buf_length);
    if (sts == OEMCrypto_ERROR_SHORT_BUFFER) {
      build_info.resize(buf_length);
      sts = OEMCrypto_BuildInformation(&build_info[0], &buf_length);
    }
    ASSERT_EQ(OEMCrypto_SUCCESS, sts);
    if (build_info.size() != buf_length) {
      build_info.resize(buf_length);
    }
    cout << "             BuildInformation: " << build_info << endl;
    OEMCrypto_WatermarkingSupport support = OEMCrypto_GetWatermarkingSupport();
    cout << "             WatermarkingSupport: " << support << endl;
  }
  ASSERT_GE(version, 8u);
  ASSERT_LE(version, kCurrentAPI);
}

/**
 * The resource rating is a number from 1 to 4. The first three levels
 * were initially defined in API 15 and they were expanded in API 16.
 */
TEST_F(OEMCryptoClientTest, ResourceRatingAPI15) {
  ASSERT_GE(OEMCrypto_ResourceRatingTier(), 1u);
  ASSERT_LE(OEMCrypto_ResourceRatingTier(), 4u);
}

/**
 * OEMCrypto must declare what type of provisioning scheme it uses.
 */
TEST_F(OEMCryptoClientTest, ProvisioningDeclaredAPI12) {
  OEMCrypto_ProvisioningMethod provisioning_method =
      OEMCrypto_GetProvisioningMethod();
  cout << "             Provisioning method = "
       << ProvisioningMethodName(provisioning_method) << endl;
  ASSERT_NE(OEMCrypto_ProvisioningError, provisioning_method);
}

TEST_F(OEMCryptoClientTest, CheckHDCPCapabilityAPI09) {
  OEMCryptoResult sts;
  OEMCrypto_HDCP_Capability current, maximum;
  sts = OEMCrypto_GetHDCPCapability(&current, &maximum);
  ASSERT_EQ(OEMCrypto_SUCCESS, sts);
  printf("             Current HDCP Capability: 0x%02x = %s.\n",
         static_cast<unsigned int>(current), HDCPCapabilityAsString(current));
  printf("             Maximum HDCP Capability: 0x%02x = %s.\n",
         static_cast<unsigned int>(maximum), HDCPCapabilityAsString(maximum));
}

TEST_F(OEMCryptoClientTest, CheckSRMCapabilityV13) {
  // This just tests some trivial functionality of the SRM update functions.
  uint16_t version = 0;
  OEMCryptoResult current_result = OEMCrypto_GetCurrentSRMVersion(&version);
  if (current_result == OEMCrypto_SUCCESS) {
    printf("             Current SRM Version: %d.\n", version);
    EXPECT_NE(OEMCrypto_SUCCESS, OEMCrypto_GetCurrentSRMVersion(nullptr));
  } else if (current_result == OEMCrypto_LOCAL_DISPLAY_ONLY) {
    printf("             Current SRM Status: Local Display Only.\n");
  } else {
    EXPECT_EQ(OEMCrypto_ERROR_NOT_IMPLEMENTED, current_result);
  }
}

TEST_F(OEMCryptoClientTest, CheckNullBuildInformationAPI17) {
  OEMCryptoResult sts;
  std::string build_info;
  sts = OEMCrypto_BuildInformation(&build_info[0], nullptr);
  ASSERT_EQ(OEMCrypto_ERROR_INVALID_CONTEXT, sts);
  size_t buf_length = 0;
  sts = OEMCrypto_BuildInformation(nullptr, &buf_length);
  // Previous versions of the test expected the wrong error code.
  // Although OEMCrypto_ERROR_INVALID_CONTEXT is still accepted by
  // the  tests, vendors should return OEMCrypto_ERROR_SHORT_BUFFER if
  // |buffer| is null and |buf_length| is zero, assigning
  // the correct length to |buf_length|.
  // TODO(231514699): Remove case for ERROR_INVALID_CONTEXT.
  ASSERT_TRUE(OEMCrypto_ERROR_SHORT_BUFFER == sts ||
              OEMCrypto_ERROR_INVALID_CONTEXT == sts);
  if (sts == OEMCrypto_ERROR_INVALID_CONTEXT) {
    printf(
        "Warning: OEMCrypto_BuildInformation should return "
        "ERROR_SHORT_BUFFER.\n");
  }
  if (sts == OEMCrypto_ERROR_SHORT_BUFFER) {
    constexpr size_t kZero = 0;
    ASSERT_GT(buf_length, kZero);
  }
}

TEST_F(OEMCryptoClientTest, CheckJsonBuildInformationAPI18) {
  std::string build_info;
  OEMCryptoResult sts = OEMCrypto_BuildInformation(&build_info[0], nullptr);
  ASSERT_EQ(OEMCrypto_ERROR_INVALID_CONTEXT, sts);
  size_t buf_length = 0;
  // OEMCrypto must allow |buffer| to be null so long as |buffer_length|
  // is provided and initially set to zero.
  sts = OEMCrypto_BuildInformation(nullptr, &buf_length);
  ASSERT_EQ(OEMCrypto_ERROR_SHORT_BUFFER, sts);
  build_info.resize(buf_length);
  const size_t max_final_size = buf_length;
  sts = OEMCrypto_BuildInformation(&build_info[0], &buf_length);
  ASSERT_EQ(OEMCrypto_SUCCESS, sts);
  ASSERT_LE(buf_length, max_final_size);
  build_info.resize(buf_length);

  jsmn_parser p;
  jsmn_init(&p);
  std::vector<jsmntok_t> tokens;
  int32_t num_tokens =
      jsmn_parse(&p, build_info.c_str(), build_info.size(), nullptr, 0);
  EXPECT_GT(num_tokens, 0)
      << "Failed to parse BuildInformation as JSON, parse returned "
      << num_tokens << "for following build info: " << build_info;

  tokens.resize(num_tokens);
  jsmn_init(&p);
  int32_t jsmn_result = jsmn_parse(&p, build_info.c_str(), build_info.size(),
                                   tokens.data(), num_tokens);
  EXPECT_GE(jsmn_result, 0)
      << "Failed to parse BuildInformation as JSON, parse returned "
      << jsmn_result << "for following build info: " << build_info;

  std::map<std::string, jsmntype_t> expected;
  expected["soc_vendor"] = JSMN_STRING;
  expected["soc_model"] = JSMN_STRING;
  expected["ta_ver"] = JSMN_STRING;
  expected["uses_opk"] = JSMN_PRIMITIVE;
  expected["tee_os"] = JSMN_STRING;
  expected["tee_os_ver"] = JSMN_STRING;

  // for values in token
  //   build string from start,end
  //   check for existence in map
  //   check if value matches expectation
  //   remove from map
  for (int i = 0; i < jsmn_result; i++) {
    jsmntok_t token = tokens[i];
    std::string key = build_info.substr(token.start, token.end - token.start);
    if (expected.find(key) != expected.end()) {
      EXPECT_EQ(expected.find(key)->second, tokens[i + 1].type)
          << "Type is incorrect for key " << key;
      expected.erase(key);
    }
  }

  // if map is not empty, return false
  if (expected.size() > 0) {
    std::string missing;
    for (auto e : expected) {
      missing.append(e.first);
      missing.append(" ");
    }
    FAIL() << "JSON does not contain all required keys. Missing keys: ["
           << missing << "] in string " << build_info;
  }
}

TEST_F(OEMCryptoClientTest, CheckMaxNumberOfSessionsAPI10) {
  size_t sessions_count;
  ASSERT_EQ(OEMCrypto_SUCCESS,
            OEMCrypto_GetNumberOfOpenSessions(&sessions_count));
  ASSERT_EQ(0u, sessions_count);
  size_t maximum;
  OEMCryptoResult sts = OEMCrypto_GetMaxNumberOfSessions(&maximum);
  ASSERT_EQ(OEMCrypto_SUCCESS, sts);
  printf("             Max Number of Sessions: %zu.\n", maximum);
  size_t required_max = GetResourceValue(kMaxConcurrentSession);
  ASSERT_GE(maximum, required_max);
}

TEST_F(OEMCryptoClientTest, CheckUsageTableSizeAPI16) {
  const size_t maximum = OEMCrypto_MaximumUsageTableHeaderSize();
  printf("             Max Usage Table Size: %zu.\n", maximum);
  // A maximum of 0 means the table is constrained by dynamic memory allocation.
  if (maximum > 0) {
    ASSERT_GE(maximum, RequiredUsageSize());
  }
}

//
// initialization tests
//
TEST_F(OEMCryptoClientTest, NormalInitTermination) {
  // Should be able to terminate OEMCrypto, and then restart it.
  ASSERT_EQ(OEMCrypto_SUCCESS, OEMCrypto_Terminate());
  OEMCrypto_SetSandbox(kTestSandbox, sizeof(kTestSandbox));
  ASSERT_EQ(OEMCrypto_SUCCESS, OEMCrypto_Initialize());
  (void)OEMCrypto_SetMaxAPIVersion(kCurrentAPI);
  (void)OEMCrypto_EnterTestMode();
}

TEST_F(OEMCryptoClientTest, CheckDTCP2CapabilityAPI17) {
  OEMCryptoResult sts;
  OEMCrypto_DTCP2_Capability capability;
  sts = OEMCrypto_GetDTCP2Capability(&capability);
  ASSERT_EQ(OEMCrypto_SUCCESS, sts);
  switch (capability) {
    case OEMCrypto_NO_DTCP2:
      printf("             Current DTCP Support: DTCP2 not supported.\n");
      break;
    case OEMCrypto_DTCP2_V1:
      printf(
          "             Current DTCP Support: Version 1 (or higher) of "
          "DTCP2 is supported.\n");
      break;
  }
}

//
// Session Tests
//
TEST_F(OEMCryptoClientTest, NormalSessionOpenClose) {
  Session s;
  ASSERT_NO_FATAL_FAILURE(s.open());
  ASSERT_NO_FATAL_FAILURE(s.close());
}

TEST_F(OEMCryptoClientTest, TwoSessionsOpenClose) {
  Session s1;
  Session s2;
  ASSERT_NO_FATAL_FAILURE(s1.open());
  ASSERT_NO_FATAL_FAILURE(s2.open());
  ASSERT_NO_FATAL_FAILURE(s1.close());
  ASSERT_NO_FATAL_FAILURE(s2.close());
}

// This test verifies that OEMCrypto can open approximately as many sessions as
// it claims.
TEST_F(OEMCryptoClientTest, MaxSessionsOpenCloseAPI10) {
  size_t sessions_count;
  ASSERT_EQ(OEMCrypto_SUCCESS,
            OEMCrypto_GetNumberOfOpenSessions(&sessions_count));
  ASSERT_EQ(0u, sessions_count);
  size_t max_sessions;
  ASSERT_EQ(OEMCrypto_SUCCESS, OEMCrypto_GetMaxNumberOfSessions(&max_sessions));
  // We expect OEMCrypto implementations support at least this many sessions.
  size_t required_number = GetResourceValue(kMaxConcurrentSession);
  ASSERT_GE(max_sessions, required_number);
  // We allow GetMaxNumberOfSessions to return an estimate.  This tests with a
  // pad of 5%. Even if it's just an estimate, we still require 8 sessions.
  size_t max_sessions_with_pad = max(max_sessions * 19 / 20, required_number);
  vector<OEMCrypto_SESSION> sessions;
  // Limit the number of sessions for testing.
  const size_t kMaxNumberOfSessionsForTesting = 0x100u;
  for (size_t i = 0; i < kMaxNumberOfSessionsForTesting; i++) {
    OEMCrypto_SESSION session_id;
    OEMCryptoResult sts = OEMCrypto_OpenSession(&session_id);
    // GetMaxNumberOfSessions might be an estimate. We allow OEMCrypto to report
    // a max that is less than what is actually supported. Assume the number
    // returned is |max|. OpenSessions shall not fail if number of active
    // sessions is less than |max|; OpenSessions should fail with
    // OEMCrypto_ERROR_TOO_MANY_SESSIONS if too many sessions are open.
    if (sts != OEMCrypto_SUCCESS) {
      ASSERT_EQ(OEMCrypto_ERROR_TOO_MANY_SESSIONS, sts);
      ASSERT_GE(i, max_sessions_with_pad);
      break;
    }
    ASSERT_EQ(OEMCrypto_SUCCESS,
              OEMCrypto_GetNumberOfOpenSessions(&sessions_count));
    ASSERT_EQ(i + 1, sessions_count);
    sessions.push_back(session_id);
  }
  for (size_t i = 0; i < sessions.size(); i++) {
    ASSERT_EQ(OEMCrypto_SUCCESS, OEMCrypto_CloseSession(sessions[i]));
    ASSERT_EQ(OEMCrypto_SUCCESS,
              OEMCrypto_GetNumberOfOpenSessions(&sessions_count));
    ASSERT_EQ(sessions.size() - i - 1, sessions_count);
  }
  if (sessions.size() == kMaxNumberOfSessionsForTesting) {
    printf(
        "             MaxSessionsOpenClose: reaches "
        "kMaxNumberOfSessionsForTesting(%zu). GetMaxNumberOfSessions = %zu. "
        "ERROR_TOO_MANY_SESSIONS not tested.",
        kMaxNumberOfSessionsForTesting, max_sessions);
  }
}

TEST_F(OEMCryptoClientTest, GenerateNonce) {
  Session s;
  ASSERT_NO_FATAL_FAILURE(s.open());
  s.GenerateNonce();
}

// Prevent a nonce flood even if each nonce is in a different session.
TEST_F(OEMCryptoClientTest, PreventNonceFlood2API16) {
  int error_counter = 0;
  const int64_t test_start = wvutil::Clock().GetCurrentTime();
  // More than 200 nonces per second should generate an error.
  // To allow for some slop, we actually test for more.
  const int flood_cutoff = 200;
  const int loop_count = flood_cutoff * 2;
  for (int i = 0; i < loop_count; i++) {
    Session s;
    ASSERT_NO_FATAL_FAILURE(s.open());
    s.GenerateNonce(&error_counter);
  }
  const int64_t test_end = wvutil::Clock().GetCurrentTime();
  int valid_counter = loop_count - error_counter;
  // Either oemcrypto should enforce a delay, or it should return an error from
  // GenerateNonce -- in either case the number of valid nonces is rate
  // limited.  We add two seconds to allow for round off error in both
  // test_start and test_end.
  EXPECT_LE(valid_counter, flood_cutoff * (test_end - test_start + 2));
  error_counter = 0;
  // After a pause, we should be able to regenerate nonces.
  wvutil::TestSleep::Sleep(2);
  Session s;
  ASSERT_NO_FATAL_FAILURE(s.open());
  s.GenerateNonce(&error_counter);
  EXPECT_EQ(0, error_counter);
}

// Prevent a nonce flood even if some nonces are in a different session.  This
// is different from the test above because there are several session open at
// the same time.  We want to make sure you can't get a flood of nonces by
// opening a flood of sessions.
TEST_F(OEMCryptoClientTest, PreventNonceFlood3API16) {
  int request_counter = 0;
  int error_counter = 0;
  const int64_t test_start = wvutil::Clock().GetCurrentTime();
  // More than 200 nonces per second should generate an error.
  // To allow for some slop, we actually test for more.
  const int flood_cutoff = 200;
  const size_t session_count = GetResourceValue(kMaxConcurrentSession);
  const size_t loop_count = 2 * flood_cutoff / session_count + 1;
  for (size_t i = 0; i < loop_count; i++) {
    std::vector<Session> s(session_count);
    for (size_t j = 0; j < session_count; j++) {
      ASSERT_NO_FATAL_FAILURE(s[j].open());
      request_counter++;
      s[j].GenerateNonce(&error_counter);
    }
  }
  const int64_t test_end = wvutil::Clock().GetCurrentTime();
  int valid_counter = request_counter - error_counter;
  // Either oemcrypto should enforce a delay, or it should return an error from
  // GenerateNonce -- in either case the number of valid nonces is rate
  // limited.  We add two seconds to allow for round off error in both
  // test_start and test_end.
  EXPECT_LE(valid_counter, flood_cutoff * (test_end - test_start + 2));
  error_counter = 0;
  // After a pause, we should be able to regenerate nonces.
  wvutil::TestSleep::Sleep(2);
  Session s;
  ASSERT_NO_FATAL_FAILURE(s.open());
  s.GenerateNonce(&error_counter);
  EXPECT_EQ(0, error_counter);
}

// This verifies that CopyBuffer works, even before a license has been loaded.
TEST_F(OEMCryptoClientTest, ClearCopyTestAPI10) {
  Session s;
  ASSERT_NO_FATAL_FAILURE(s.open());
  const int kDataSize = 256;
  vector<uint8_t> input_buffer(kDataSize);
  GetRandBytes(input_buffer.data(), input_buffer.size());
  vector<uint8_t> output_buffer(kDataSize);
  OEMCrypto_DestBufferDesc dest_buffer_descriptor;
  dest_buffer_descriptor.type = OEMCrypto_BufferType_Clear;
  dest_buffer_descriptor.buffer.clear.clear_buffer = output_buffer.data();
  dest_buffer_descriptor.buffer.clear.clear_buffer_length =
      output_buffer.size();
  ASSERT_EQ(OEMCrypto_SUCCESS,
            CopyBuffer(s.session_id(), input_buffer.data(), input_buffer.size(),
                       &dest_buffer_descriptor,
                       OEMCrypto_FirstSubsample | OEMCrypto_LastSubsample));
  ASSERT_EQ(input_buffer, output_buffer);
  ASSERT_EQ(OEMCrypto_ERROR_INVALID_CONTEXT,
            CopyBuffer(s.session_id(), nullptr, input_buffer.size(),
                       &dest_buffer_descriptor,
                       OEMCrypto_FirstSubsample | OEMCrypto_LastSubsample));
  ASSERT_EQ(
      OEMCrypto_ERROR_INVALID_CONTEXT,
      CopyBuffer(s.session_id(), input_buffer.data(), input_buffer.size(),
                 nullptr, OEMCrypto_FirstSubsample | OEMCrypto_LastSubsample));
  dest_buffer_descriptor.buffer.clear.clear_buffer = nullptr;
  ASSERT_EQ(OEMCrypto_ERROR_INVALID_CONTEXT,
            CopyBuffer(s.session_id(), input_buffer.data(), input_buffer.size(),
                       &dest_buffer_descriptor,
                       OEMCrypto_FirstSubsample | OEMCrypto_LastSubsample));
  dest_buffer_descriptor.buffer.clear.clear_buffer = output_buffer.data();
  dest_buffer_descriptor.buffer.clear.clear_buffer_length =
      output_buffer.size() - 1;
  ASSERT_NE(OEMCrypto_SUCCESS,
            CopyBuffer(s.session_id(), input_buffer.data(), input_buffer.size(),
                       &dest_buffer_descriptor,
                       OEMCrypto_FirstSubsample | OEMCrypto_LastSubsample));
}

// This verifies that CopyBuffer works on the maximum required buffer size.
TEST_F(OEMCryptoClientTest, ClearCopyTestLargeSubsample) {
  Session s;
  ASSERT_NO_FATAL_FAILURE(s.open());
  size_t max_size = GetResourceValue(kMaxSubsampleSize);
  vector<uint8_t> input_buffer(max_size);
  GetRandBytes(input_buffer.data(), input_buffer.size());
  vector<uint8_t> output_buffer(max_size);
  OEMCrypto_DestBufferDesc dest_buffer_descriptor;
  dest_buffer_descriptor.type = OEMCrypto_BufferType_Clear;
  dest_buffer_descriptor.buffer.clear.clear_buffer = output_buffer.data();
  dest_buffer_descriptor.buffer.clear.clear_buffer_length =
      output_buffer.size();
  ASSERT_EQ(OEMCrypto_SUCCESS,
            CopyBuffer(s.session_id(), input_buffer.data(), input_buffer.size(),
                       &dest_buffer_descriptor,
                       OEMCrypto_FirstSubsample | OEMCrypto_LastSubsample));
  ASSERT_EQ(input_buffer, output_buffer);
}

TEST_F(OEMCryptoClientTest,
       OEMCryptoMemoryCopyBufferForOutOfRangeHandleLength) {
  Session s;
  ASSERT_NO_FATAL_FAILURE(s.open());
  vector<uint8_t> input_buffer;
  OEMCrypto_DestBufferDesc dest_buffer_descriptor;
  dest_buffer_descriptor.type = OEMCrypto_BufferType_Secure;

  size_t buffer_length = KiB;
  input_buffer.resize(buffer_length);
  int secure_fd;
  if (OEMCrypto_AllocateSecureBuffer(s.session_id(), buffer_length,
                                     &dest_buffer_descriptor,
                                     &secure_fd) != OEMCrypto_SUCCESS) {
    LOGI("Secure buffers are not supported.");
    return;
  }

  dest_buffer_descriptor.buffer.secure.secure_buffer_length =
      kHugeInputBufferLength;
  ASSERT_NO_FATAL_FAILURE(
      OEMCrypto_CopyBuffer(s.session_id(), input_buffer.data(), buffer_length,
                           &dest_buffer_descriptor,
                           OEMCrypto_FirstSubsample | OEMCrypto_LastSubsample));
  OEMCrypto_FreeSecureBuffer(s.session_id(), &dest_buffer_descriptor,
                             secure_fd);
}

TEST_F(OEMCryptoClientTest, ClearCopyTestInvalidSubsampleFlag) {
  uint8_t oemcrypto_invalid_subsample_flag = 85;
  Session s;
  ASSERT_NO_FATAL_FAILURE(s.open());
  size_t max_size = GetResourceValue(kMaxSubsampleSize);
  vector<uint8_t> input_buffer(max_size);
  GetRandBytes(input_buffer.data(), input_buffer.size());
  vector<uint8_t> output_buffer(max_size);
  OEMCrypto_DestBufferDesc dest_buffer_descriptor;
  dest_buffer_descriptor.type = OEMCrypto_BufferType_Clear;
  dest_buffer_descriptor.buffer.clear.clear_buffer = output_buffer.data();
  dest_buffer_descriptor.buffer.clear.clear_buffer_length =
      output_buffer.size();
  ASSERT_NO_FATAL_FAILURE(
      CopyBuffer(s.session_id(), input_buffer.data(), input_buffer.size(),
                 &dest_buffer_descriptor, oemcrypto_invalid_subsample_flag));
}

TEST_F(OEMCryptoClientTest, CanLoadTestKeys) {
  ASSERT_NE(DeviceFeatures::NO_METHOD, global_features.derive_key_method)
      << "Session tests cannot run with out a test keybox or RSA cert.";
}

/// @}
}  // namespace wvoec