Files
ce_cdm/core/test/test_base.cpp
2020-02-11 14:22:17 -08:00

671 lines
26 KiB
C++

// Copyright 2018 Google LLC. All Rights Reserved. This file and proprietary
// source code may only be used and distributed under the Widevine Master
// License Agreement.
// This file adds some print methods so that when unit tests fail, the
// will print the name of an enumeration instead of the numeric value.
#include "test_base.h"
#include <openssl/aes.h>
#include <openssl/bio.h>
#include <openssl/cmac.h>
#include <stdlib.h>
#include <string>
#include <vector>
#include "cdm_engine.h"
#include "crypto_session.h"
#include "file_store.h"
#include "license.h"
#include "log.h"
#include "oec_device_features.h"
#include "oec_test_data.h"
#include "platform.h"
#include "properties.h"
#include "test_printers.h"
#include "url_request.h"
using wvcdm::metrics::EngineMetrics;
namespace wvcdm {
namespace {
void show_menu(const char* prog_name, const std::string& extra_help_text) {
std::cout << std::endl;
std::cout << "usage: " << prog_name << " [options]" << std::endl << std::endl;
std::cout << " enclose multiple arguments in '' when using adb shell"
<< std::endl;
std::cout << " e.g. adb shell '" << prog_name << " --server=\"url\"'"
<< std::endl;
std::cout << " --verbose or -v" << std::endl;
std::cout << " increase logging verbosity (may be repeated)" << std::endl
<< std::endl;
std::cout << " --no_filter" << std::endl;
std::cout << " Do not filter out inappropriate tests" << std::endl
<< std::endl;
std::cout << " --cast" << std::endl;
std::cout << " Run tests appropriate for a Cast Receiver" << std::endl
<< std::endl;
std::cout << " --license_server_id=<gp/cp/st>" << std::endl;
std::cout << " specifies which default server settings to use: "
<< std::endl;
std::cout << " gp for GooglePlay server" << std::endl;
std::cout << " cp for Content Protection UAT server" << std::endl;
std::cout << " st for Content Protection Staging server" << std::endl
<< std::endl;
std::cout << " --keyid=<key_id>" << std::endl;
std::cout << " configure the key id or pssh, in hex format" << std::endl
<< std::endl;
std::cout << " --service_certificate=<cert>" << std::endl;
std::cout << " configure the signed license service certificate" << std::endl;
std::cout << " Specify the SignedDeviceCertificate (from "
<< "device_certificate.proto) " << std::endl;
std::cout << " in hex format." << std::endl;
std::cout << " Due to the length of the argument use, " << std::endl;
std::cout << " echo \"/system/bin/request_license_test -s \\\""
<< "0ABF02...A29914\\\"\" \\" << std::endl;
std::cout << " > run_request_license_test.sh" << std::endl;
std::cout << " chmod +x run_request_license_test.sh" << std::endl;
std::cout << " adb push run_request_license_test.sh /system/bin"
<< std::endl;
std::cout << " adb shell sh /system/bin/run_request_license_test.sh"
<< std::endl << std::endl;
std::cout << " --provisioning_certificate=<cert>" << std::endl;
std::cout << " configure the signed provisioning service certificate" << std::endl
<< " in hex" << std::endl << std::endl;
std::cout << " --license_server_url=<url>" << std::endl;
std::cout << " configure the license server url, please include http[s]"
<< " in the url" << std::endl
<< std::endl;
std::cout << " --provisioning_server_url=<url>" << std::endl;
std::cout << " configure the provisioning server url, please include http[s]"
<< " in the url" << std::endl
<< std::endl;
std::cout << extra_help_text << std::endl;
}
/*
* Locate the portion of the server's response message that is between
* the strings jason_start_substr and json_end_substr. Returns the string
* through *result. If the start substring match fails, assume the entire
* string represents a serialized protobuf mesaage and return true with
* the entire string. If the end_substring match fails, return false with
* an empty *result.
*/
bool ExtractSignedMessage(const std::string& response,
const std::string& json_start_substr,
const std::string& json_end_substr,
std::string* result) {
std::string response_string;
size_t start = response.find(json_start_substr);
if (start == response.npos) {
// Assume serialized protobuf message.
result->assign(response);
} else {
// Assume JSON-wrapped protobuf.
size_t end =
response.find(json_end_substr, start + json_start_substr.length());
if (end == response.npos) {
LOGE("ExtractSignedMessage cannot locate end substring");
result->clear();
return false;
}
size_t result_string_size = end - start - json_start_substr.length();
result->assign(response, start + json_start_substr.length(),
result_string_size);
}
if (result->empty()) {
LOGE("ExtractSignedMessage: Response message is empty");
return false;
}
return true;
}
} // namespace
ConfigTestEnv WvCdmTestBase::default_config_(kContentProtectionUatServer);
void WvCdmTestBase::StripeBuffer(std::vector<uint8_t>* buffer, size_t size,
uint8_t init) {
buffer->assign(size, 0);
for (size_t i = 0; i < size; i++) {
(*buffer)[i] = init + i % 250;
}
}
std::string WvCdmTestBase::Aes128CbcEncrypt(std::vector<uint8_t> key,
const std::vector<uint8_t>& clear,
const std::vector<uint8_t> iv) {
std::vector<uint8_t> encrypted(clear.size());
std::vector<uint8_t> iv_mod(iv.begin(), iv.end());
AES_KEY aes_key;
AES_set_encrypt_key(&key[0], 128, &aes_key);
AES_cbc_encrypt(&clear[0], &encrypted[0], clear.size(), &aes_key, &iv_mod[0],
AES_ENCRYPT);
return std::string(encrypted.begin(), encrypted.end());
}
std::string WvCdmTestBase::Aes128CbcDecrypt(std::vector<uint8_t> key,
const std::vector<uint8_t>& clear,
const std::vector<uint8_t> iv) {
std::vector<uint8_t> encrypted(clear.size());
std::vector<uint8_t> iv_mod(iv.begin(), iv.end());
AES_KEY aes_key;
AES_set_decrypt_key(&key[0], 128, &aes_key);
AES_cbc_encrypt(&clear[0], &encrypted[0], clear.size(), &aes_key, &iv_mod[0],
AES_DECRYPT);
return std::string(encrypted.begin(), encrypted.end());
}
std::string WvCdmTestBase::SignHMAC(const std::string& message,
const std::vector<uint8_t>& key) {
uint8_t signature[SHA256_DIGEST_LENGTH];
unsigned int md_len = SHA256_DIGEST_LENGTH;
HMAC(EVP_sha256(), &key[0], key.size(),
reinterpret_cast<const uint8_t*>(message.data()), message.size(),
signature, &md_len);
std::string result(signature, signature + SHA256_DIGEST_LENGTH);
return result;
}
TestCryptoSession::TestCryptoSession(metrics::CryptoMetrics* crypto_metrics)
: CryptoSession(crypto_metrics) {
// The first CryptoSession should have initialized OEMCrypto. This is right
// after that, so should tell oemcrypto to use a test keybox.
if (session_count() == 1) {
WvCdmTestBase::InstallTestRootOfTrust();
}
}
CdmResponseType TestCryptoSession::GenerateNonce(uint32_t* nonce) {
CdmResponseType status = CryptoSession::GenerateNonce(nonce);
for (int i = 0; status != NO_ERROR; i++) {
LOGV("Recovering from nonce flood.");
if (i > 2) return status;
sleep(1);
status = CryptoSession::GenerateNonce(nonce);
}
return NO_ERROR;
}
class TestCryptoSessionFactory : public CryptoSessionFactory {
CryptoSession* MakeCryptoSession(metrics::CryptoMetrics* crypto_metrics) {
// We need to add extra locking here because we need to make sure that there
// are no other OEMCrypto calls between OEMCrypto_Initialize and
// InstallTestRootOfTrust. OEMCrypto_Initialize is called in the production
// CryptoSession::Init and is wrapped in crypto_lock_, but
// InstallTestRootOfTrust is only called in the constructor of the
// TestCryptoSession, above.
std::unique_lock<std::mutex> auto_lock(init_lock_);
return new TestCryptoSession(crypto_metrics);
}
std::mutex init_lock_;
};
void WvCdmTestBase::SetUp() {
::testing::Test::SetUp();
Properties::Init();
Properties::set_provisioning_messages_are_binary(binary_provisioning_);
// Log the current test name, to help with debugging when the log and stdout
// are not the same.
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());
// Some test environments allow the model name of the device to be set
// dynamically using an environment variable. The model name will show up in
// the license server logs as the part of the device idenfication as
// "model_name".
std::string model_name =
std::string(test_info->test_case_name()) + "." + test_info->name();
int overwrite = 1; // Set value even if already set.
setenv("MODEL_NAME", model_name.c_str(), overwrite);
CryptoSession::SetCryptoSessionFactory(new TestCryptoSessionFactory());
// TODO(fredgc): Add a test version of DeviceFiles.
}
void WvCdmTestBase::InstallTestRootOfTrust() {
switch (wvoec::global_features.derive_key_method) {
case wvoec::DeviceFeatures::LOAD_TEST_KEYBOX:
ASSERT_EQ(OEMCrypto_SUCCESS,
OEMCrypto_LoadTestKeybox(
reinterpret_cast<const uint8_t*>(&wvoec::kTestKeybox),
sizeof(wvoec::kTestKeybox)));
break;
case wvoec::DeviceFeatures::LOAD_TEST_RSA_KEY:
// Rare case: used by devices with baked in DRM cert.
ASSERT_EQ(OEMCrypto_SUCCESS, OEMCrypto_LoadTestRSAKey());
break;
case wvoec::DeviceFeatures::TEST_PROVISION_30:
// Can use oem certificate to install test rsa key.
break;
default:
FAIL() << "Cannot run test without test keybox or RSA key installed.";
}
}
void WvCdmTestBase::Provision() {
CdmProvisioningRequest prov_request;
CdmProvisioningRequest binary_prov_request;
std::string provisioning_server_url;
CdmCertificateType cert_type = kCertificateWidevine;
std::string cert_authority;
std::string cert, wrapped_key;
CdmSessionId session_id;
FileSystem file_system;
// TODO(fredgc): provision for different SPOIDs.
CdmEngine cdm_engine(&file_system,
std::shared_ptr<EngineMetrics>(new EngineMetrics));
CdmResponseType result = cdm_engine.GetProvisioningRequest(
cert_type, cert_authority, config_.provisioning_service_certificate(),
&prov_request, &provisioning_server_url);
ASSERT_EQ(NO_ERROR, result);
if (binary_provisioning_) {
binary_prov_request = prov_request;
prov_request = std::string(Base64SafeEncodeNoPad(std::vector<uint8_t>(
binary_prov_request.begin(), binary_prov_request.end())));
}
LOGV("WvCdmTestBase::Provision: req=%s", prov_request.c_str());
// Ignore URL provided by CdmEngine. Use ours, as configured
// for test vs. production server.
provisioning_server_url.assign(config_.provisioning_server());
UrlRequest url_request(provisioning_server_url);
EXPECT_TRUE(url_request.is_connected());
url_request.PostCertRequestInQueryString(prov_request);
std::string http_message;
bool ok = url_request.GetResponse(&http_message);
EXPECT_TRUE(ok) << http_message;
LOGV("WvCdmTestBase::Provision: http_message: \n%s\n", http_message.c_str());
if (binary_provisioning_) {
// extract provisioning response from received message
// Extracts signed response from JSON string, result is serialized protobuf.
const std::string kMessageStart = "\"signedResponse\": \"";
const std::string kMessageEnd = "\"";
std::string protobuf_response;
EXPECT_TRUE(ExtractSignedMessage(http_message, kMessageStart, kMessageEnd,
&protobuf_response))
<< "Failed to extract signed serialized response from JSON response";
LOGV("WvCdmEnginePreProvTest::Provision: extracted response message: \n"
"%s\n", protobuf_response.c_str());
// base64 decode response to yield binary protobuf
std::vector<uint8_t> response_vec(Base64SafeDecode(
std::string(protobuf_response.begin(), protobuf_response.end())));
std::string binary_protobuf_response(response_vec.begin(),
response_vec.end());
ASSERT_EQ(NO_ERROR, cdm_engine.HandleProvisioningResponse(
binary_protobuf_response, &cert, &wrapped_key))
<< "message = " << http_message;
} else {
ASSERT_EQ(NO_ERROR, cdm_engine.HandleProvisioningResponse(
http_message, &cert, &wrapped_key))
<< "message = " << http_message;
}
}
// TODO(fredgc): Replace this with a pre-defined DRM certificate. We could do
// that because either the device is using a known test keybox with a known
// device key, or the device is using an OEM certificate, and we can extract
// that certificate from the provisioning request.
void WvCdmTestBase::EnsureProvisioned() {
CdmSessionId session_id;
FileSystem file_system;
CdmEngine cdm_engine(&file_system,
std::shared_ptr<EngineMetrics>(new EngineMetrics));
CdmResponseType status =
cdm_engine.OpenSession(config_.key_system(), NULL, NULL, &session_id);
if (status == NEED_PROVISIONING) {
Provision();
status =
cdm_engine.OpenSession(config_.key_system(), NULL, NULL, &session_id);
}
ASSERT_EQ(NO_ERROR, status);
ASSERT_NE("", session_id) << "Could not open CDM session.";
ASSERT_TRUE(cdm_engine.IsOpenSession(session_id));
ASSERT_EQ(NO_ERROR, cdm_engine.CloseSession(session_id));
}
bool WvCdmTestBase::Initialize(int argc, const char* const argv[],
const std::string& extra_help_text) {
Properties::Init();
bool is_cast_receiver = false;
bool force_load_test_keybox = false; // TODO(fredgc): obsolete. remove.
bool filter_tests = true;
bool show_usage = false;
int verbosity = 0;
// Skip the first element, which is the program name.
const std::vector<std::string> args(argv + 1, argv + argc);
for (const std::string& arg : args) {
if (arg == "--verbose" || arg == "-v") {
++verbosity;
} else if (arg == "--no_filter") {
filter_tests = false;
} else if (arg == "--cast") {
is_cast_receiver = true;
} else {
const auto index = arg.find('=');
if (index == std::string::npos) {
std::cerr << "Argument values need to be specified using --arg=foo" << std::endl;
show_usage = true;
break;
}
const std::string arg_prefix = arg.substr(0, index);
const std::string arg_value = arg.substr(index + 1);
if (arg_prefix == "--license_server_id") {
if (arg_value == "gp") {
default_config_ = ConfigTestEnv(kGooglePlayServer);
} else if (arg_value == "cp") {
default_config_ = ConfigTestEnv(kContentProtectionUatServer);
} else if (arg_value == "st") {
default_config_ = ConfigTestEnv(kContentProtectionStagingServer);
} else {
std::cerr << "Invalid license server id: " << arg_value << std::endl;
show_usage = true;
break;
}
} else if (arg_prefix == "--keyid") {
default_config_.set_key_id(arg_value);
} else if (arg_prefix == "--service_certificate") {
const std::string certificate(a2bs_hex(arg_value));
default_config_.set_license_service_certificate(certificate);
} else if (arg_prefix == "--provisioning_certificate") {
const std::string certificate(a2bs_hex(arg_value));
default_config_.set_provisioning_service_certificate(certificate);
} else if (arg_prefix == "--license_server_url") {
default_config_.set_license_server(arg_value);
} else if (arg_prefix == "--provisioning_server_url") {
default_config_.set_provisioning_server(arg_value);
} else {
std::cerr << "Unknown argument " << arg_prefix << std::endl;
show_usage = true;
break;
}
}
}
if (show_usage) {
show_menu(argv[0], extra_help_text);
return false;
}
g_cutoff = static_cast<LogPriority>(verbosity);
// Displays server url, port and key Id being used
std::cout << std::endl;
std::cout << "Default Server: " << default_config_.license_server()
<< std::endl;
std::cout << "Default KeyID: " << default_config_.key_id() << std::endl
<< std::endl;
// Figure out which tests are appropriate for OEMCrypto, based on features
// supported.
wvoec::global_features.Initialize(is_cast_receiver, force_load_test_keybox);
// If the user requests --no_filter, we don't change the filter, otherwise, we
// filter out features that are not supported.
if (filter_tests) {
::testing::GTEST_FLAG(filter) =
wvoec::global_features.RestrictFilter(::testing::GTEST_FLAG(filter));
}
return true;
}
TestLicenseHolder::TestLicenseHolder(CdmEngine* cdm_engine)
: cdm_engine_(cdm_engine),
session_opened_(false),
// Keys are initialized with simple values, and the correct size:
derived_mac_key_server_(MAC_KEY_SIZE, 'a'),
derived_mac_key_client_(MAC_KEY_SIZE, 'b'),
mac_key_server_(MAC_KEY_SIZE, 'c'),
mac_key_client_(MAC_KEY_SIZE, 'd'),
enc_key_(CONTENT_KEY_SIZE, 'e'),
session_key_(CONTENT_KEY_SIZE, 'f') {}
TestLicenseHolder::~TestLicenseHolder() {
CloseSession();
}
void TestLicenseHolder::OpenSession(const std::string& key_system) {
CdmResponseType status =
cdm_engine_->OpenSession(key_system, NULL, NULL, &session_id_);
ASSERT_EQ(status, NO_ERROR);
ASSERT_NE("", session_id_) << "Could not open CDM session.";
ASSERT_TRUE(cdm_engine_->IsOpenSession(session_id_));
session_opened_ = true;
}
void TestLicenseHolder::CloseSession() {
if (session_opened_) {
cdm_engine_->CloseSession(session_id_);
session_opened_ = false;
}
}
void TestLicenseHolder::GenerateKeyRequest(
const std::string& key_id, const std::string& init_data_type_string) {
ASSERT_TRUE(session_opened_);
CdmAppParameterMap app_parameters;
CdmKeySetId key_set_id;
InitializationData init_data(init_data_type_string, key_id);
CdmKeyRequest key_request;
CdmResponseType result = cdm_engine_->GenerateKeyRequest(
session_id_, key_set_id, init_data, kLicenseTypeStreaming, app_parameters,
&key_request);
EXPECT_EQ(KEY_MESSAGE, result);
signed_license_request_data_ = key_request.message;
EXPECT_EQ(kKeyRequestTypeInitial, key_request.type);
}
void TestLicenseHolder::CreateDefaultLicense() {
video_widevine::SignedMessage signed_message;
EXPECT_TRUE(signed_message.ParseFromString(signed_license_request_data_));
license_request_data_ = signed_message.msg();
video_widevine::LicenseRequest license_request;
EXPECT_TRUE(license_request.ParseFromString(license_request_data_));
video_widevine::ClientIdentification client_id = license_request.client_id();
EXPECT_EQ(
video_widevine::ClientIdentification_TokenType_DRM_DEVICE_CERTIFICATE,
client_id.type());
// Extract the RSA key from the DRM certificate.
std::string token = client_id.token();
video_widevine::SignedDrmDeviceCertificate signed_drm_cert;
EXPECT_TRUE(signed_drm_cert.ParseFromString(token));
video_widevine::DrmDeviceCertificate drm_cert;
EXPECT_TRUE(drm_cert.ParseFromString(signed_drm_cert.drm_certificate()));
EXPECT_TRUE(rsa_key_.Init(drm_cert.public_key()));
EXPECT_TRUE(rsa_key_.VerifySignature(signed_message.msg(),
signed_message.signature()));
DeriveKeysFromSessionKey();
video_widevine::LicenseIdentification* license_id = license()->mutable_id();
license_id->set_request_id("TestCase");
license_id->set_session_id(session_id_);
license_id->set_type(video_widevine::STREAMING);
license_id->set_version(0);
::video_widevine::License_Policy* policy = license()->mutable_policy();
policy->set_can_play(true);
policy->set_can_persist(false);
policy->set_can_renew(false);
policy->set_playback_duration_seconds(0);
policy->set_license_duration_seconds(0);
AddMacKey();
}
void TestLicenseHolder::AddMacKey() {
video_widevine::License_KeyContainer* key_container = license()->add_key();
std::vector<uint8_t> iv(KEY_IV_SIZE, 'v');
std::string iv_s(iv.begin(), iv.end());
key_container->set_iv(iv_s);
key_container->set_type(video_widevine::License_KeyContainer_KeyType_SIGNING);
// Combine server and client mac keys.
std::vector<uint8_t> keys(mac_key_server_);
keys.insert(keys.end(), mac_key_client_.begin(), mac_key_client_.end());
std::string encrypted_keys =
WvCdmTestBase::Aes128CbcEncrypt(enc_key_, keys, iv);
key_container->set_key(encrypted_keys);
}
video_widevine::License_KeyContainer* TestLicenseHolder::AddKey(
const KeyId& key_id, const std::vector<uint8_t>& key_data,
const wvoec::KeyControlBlock& block_in) {
video_widevine::License_KeyContainer* key_container = license()->add_key();
wvoec::KeyControlBlock block = block_in;
if (block.verification[0] == 0) {
block.verification[0] = 'k';
block.verification[1] = 'c';
block.verification[2] = '1';
// This will work until oemcrypto api 20.
block.verification[3] = '0' + wvoec::global_features.api_version - 10;
}
key_container->set_id(key_id);
key_container->set_type(video_widevine::License_KeyContainer_KeyType_CONTENT);
key_container->set_level(
video_widevine::License_KeyContainer_SecurityLevel_SW_SECURE_CRYPTO);
std::vector<uint8_t> iv(KEY_IV_SIZE, 'v');
std::string iv_s(iv.begin(), iv.end());
key_container->set_iv(iv_s);
std::string encrypted_key_data =
WvCdmTestBase::Aes128CbcEncrypt(enc_key_, key_data, iv);
// TODO(b/111069024): remove this!
std::string padding(CONTENT_KEY_SIZE, '-');
key_container->set_key(encrypted_key_data + padding);
std::vector<uint8_t> block_v(
reinterpret_cast<const uint8_t*>(&block),
reinterpret_cast<const uint8_t*>(&block) + sizeof(block));
std::vector<uint8_t> block_iv(KEY_IV_SIZE, 'w');
std::string block_iv_s(block_iv.begin(), block_iv.end());
std::string encrypted_block =
WvCdmTestBase::Aes128CbcEncrypt(key_data, block_v, block_iv);
key_container->mutable_key_control()->set_iv(block_iv_s);
key_container->mutable_key_control()->set_key_control_block(encrypted_block);
return key_container;
}
void TestLicenseHolder::SignAndLoadLicense() {
#if 0 // Need to turn off protobuf_lite to use this.
LOGV("License = %s\n", license_.DebugString().c_str());
#endif
std::string license_data;
license_.SerializeToString(&license_data);
std::string signature =
WvCdmTestBase::SignHMAC(license_data, derived_mac_key_server_);
std::string session_key_s(session_key_.begin(), session_key_.end());
std::string encrypted_session_key;
EXPECT_TRUE(rsa_key_.Encrypt(session_key_s, &encrypted_session_key));
video_widevine::SignedMessage signed_response;
signed_response.set_msg(license_data);
signed_response.set_type(video_widevine::SignedMessage_MessageType_LICENSE);
signed_response.set_session_key(encrypted_session_key);
signed_response.set_signature(signature);
std::string response_data;
signed_response.SerializeToString(&response_data);
CdmKeySetId key_set_id;
CdmLicenseType license_type; // Required for AddKey. Result value ignored.
EXPECT_EQ(KEY_ADDED,
cdm_engine_->AddKey(session_id_, response_data,
&license_type, &key_set_id));
}
void TestLicenseHolder::DeriveKeysFromSessionKey() {
std::string context;
GenerateMacContext(license_request_data_, &context);
std::vector<uint8_t> mac_key_context(context.begin(), context.end());
GenerateEncryptContext(license_request_data_, &context);
std::vector<uint8_t> enc_key_context(context.begin(), context.end());
ASSERT_TRUE(
DeriveKey(session_key_, mac_key_context, 1, &derived_mac_key_server_));
std::vector<uint8_t> mac_key_part2;
ASSERT_TRUE(DeriveKey(session_key_, mac_key_context, 2, &mac_key_part2));
derived_mac_key_server_.insert(derived_mac_key_server_.end(),
mac_key_part2.begin(), mac_key_part2.end());
ASSERT_TRUE(
DeriveKey(session_key_, mac_key_context, 3, &derived_mac_key_client_));
ASSERT_TRUE(DeriveKey(session_key_, mac_key_context, 4, &mac_key_part2));
derived_mac_key_client_.insert(derived_mac_key_client_.end(),
mac_key_part2.begin(), mac_key_part2.end());
std::vector<uint8_t> enc_key;
ASSERT_TRUE(DeriveKey(session_key_, enc_key_context, 1, &enc_key_));
}
bool TestLicenseHolder::DeriveKey(const std::vector<uint8_t>& key,
const std::vector<uint8_t>& context,
int counter, std::vector<uint8_t>* out) {
if (key.empty() || counter > 4 || context.empty() || out == NULL) {
LOGE("DeriveKey(): bad context");
return false;
}
const EVP_CIPHER* cipher = EVP_aes_128_cbc();
CMAC_CTX* cmac_ctx = CMAC_CTX_new();
if (!cmac_ctx) {
LOGE("DeriveKey(): cmac failure");
return false;
}
if (!CMAC_Init(cmac_ctx, &key[0], key.size(), cipher, 0)) {
LOGE("DeriveKey(): CMAC_Init");
CMAC_CTX_free(cmac_ctx);
return false;
}
std::vector<uint8_t> message;
message.push_back(counter);
message.insert(message.end(), context.begin(), context.end());
if (!CMAC_Update(cmac_ctx, &message[0], message.size())) {
LOGE("DeriveKey(): CMAC_Update");
CMAC_CTX_free(cmac_ctx);
return false;
}
size_t reslen;
uint8_t res[128];
if (!CMAC_Final(cmac_ctx, res, &reslen)) {
LOGE("DeriveKey(): CMAC_Final");
CMAC_CTX_free(cmac_ctx);
return false;
}
out->assign(res, res + reslen);
CMAC_CTX_free(cmac_ctx);
return true;
}
} // namespace wvcdm