provisioner/rkp_factory_extraction_lib.cpp - platform/system/security - Git at Google

 /*
  * Copyright 2022 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 "rkp_factory_extraction_lib.h"

 #include <aidl/android/hardware/security/keymint/IRemotelyProvisionedComponent.h>
 #include <android-base/properties.h>
 #include <android/binder_manager.h>
 #include <cppbor.h>
 #include <cstddef>
 #include <cstdint>
 #include <cstring>
 #include <iterator>
 #include <keymaster/cppcose/cppcose.h>
 #include <openssl/base64.h>
 #include <remote_prov/remote_prov_utils.h>
 #include <sys/random.h>

 #include <memory>
 #include <optional>
 #include <string>
 #include <string_view>
 #include <vector>

 #include "cppbor_parse.h"

 using aidl::android::hardware::security::keymint::DeviceInfo;
 using aidl::android::hardware::security::keymint::IRemotelyProvisionedComponent;
 using aidl::android::hardware::security::keymint::MacedPublicKey;
 using aidl::android::hardware::security::keymint::ProtectedData;
 using aidl::android::hardware::security::keymint::RpcHardwareInfo;
 using aidl::android::hardware::security::keymint::remote_prov::EekChain;
 using aidl::android::hardware::security::keymint::remote_prov::generateEekChain;
 using aidl::android::hardware::security::keymint::remote_prov::getProdEekChain;
 using aidl::android::hardware::security::keymint::remote_prov::jsonEncodeCsrWithBuild;
 using aidl::android::hardware::security::keymint::remote_prov::parseAndValidateFactoryDeviceInfo;
 using aidl::android::hardware::security::keymint::remote_prov::verifyFactoryCsr;
 using aidl::android::hardware::security::keymint::remote_prov::verifyFactoryProtectedData;

 using namespace cppbor;
 using namespace cppcose;

 constexpr size_t kVersionWithoutSuperencryption = 3;

 std::string toBase64(const std::vector<uint8_t>& buffer) {
     size_t base64Length;
     int rc = EVP_EncodedLength(&base64Length, buffer.size());
     if (!rc) {
         std::cerr << "Error getting base64 length. Size overflow?" << std::endl;
         exit(-1);
     }

     std::string base64(base64Length, ' ');
     rc = EVP_EncodeBlock(reinterpret_cast<uint8_t*>(base64.data()), buffer.data(), buffer.size());
     ++rc;  // Account for NUL, which BoringSSL does not for some reason.
     if (rc != base64Length) {
         std::cerr << "Error writing base64. Expected " << base64Length
                   << " bytes to be written, but " << rc << " bytes were actually written."
                   << std::endl;
         exit(-1);
     }

     // BoringSSL automatically adds a NUL -- remove it from the string data
     base64.pop_back();

     return base64;
 }

 std::vector<uint8_t> generateChallenge() {
     std::vector<uint8_t> challenge(kChallengeSize);

     ssize_t bytesRemaining = static_cast<ssize_t>(challenge.size());
     uint8_t* writePtr = challenge.data();
     while (bytesRemaining > 0) {
         int bytesRead = getrandom(writePtr, bytesRemaining, /*flags=*/0);
         if (bytesRead < 0) {
             if (errno == EINTR) {
                 continue;
             } else {
                 std::cerr << errno << ": " << strerror(errno) << std::endl;
                 exit(-1);
             }
         }
         bytesRemaining -= bytesRead;
         writePtr += bytesRead;
     }

     return challenge;
 }

 CborResult<Array> composeCertificateRequestV1(const ProtectedData& protectedData,
                                               const DeviceInfo& verifiedDeviceInfo,
                                               const std::vector<uint8_t>& challenge,
                                               const std::vector<uint8_t>& keysToSignMac,
                                               IRemotelyProvisionedComponent* provisionable) {
     Array macedKeysToSign = Array()
                                 .add(Map().add(1, 5).encode())  // alg: hmac-sha256
                                 .add(Map())                     // empty unprotected headers
                                 .add(Null())                    // nil for the payload
                                 .add(keysToSignMac);            // MAC as returned from the HAL

     ErrMsgOr<std::unique_ptr<Map>> parsedVerifiedDeviceInfo =
         parseAndValidateFactoryDeviceInfo(verifiedDeviceInfo.deviceInfo, provisionable);
     if (!parsedVerifiedDeviceInfo) {
         return {nullptr, parsedVerifiedDeviceInfo.moveMessage()};
     }

     auto [parsedProtectedData, ignore2, errMsg] = parse(protectedData.protectedData);
     if (!parsedProtectedData) {
         std::cerr << "Error parsing protected data: '" << errMsg << "'" << std::endl;
         return {nullptr, errMsg};
     }

     Array deviceInfo = Array().add(parsedVerifiedDeviceInfo.moveValue()).add(Map());

     auto certificateRequest = std::make_unique<Array>();
     (*certificateRequest)
         .add(std::move(deviceInfo))
         .add(challenge)
         .add(std::move(parsedProtectedData))
         .add(std::move(macedKeysToSign));
     return {std::move(certificateRequest), ""};
 }

 CborResult<Array> getCsrV1(std::string_view componentName, IRemotelyProvisionedComponent* irpc) {
     std::vector<uint8_t> keysToSignMac;
     std::vector<MacedPublicKey> emptyKeys;
     DeviceInfo verifiedDeviceInfo;
     ProtectedData protectedData;
     RpcHardwareInfo hwInfo;
     ::ndk::ScopedAStatus status = irpc->getHardwareInfo(&hwInfo);
     if (!status.isOk()) {
         std::cerr << "Failed to get hardware info for '" << componentName
                   << "'. Description: " << status.getDescription() << "." << std::endl;
         exit(-1);
     }

     const std::vector<uint8_t> eek = getProdEekChain(hwInfo.supportedEekCurve);
     const std::vector<uint8_t> challenge = generateChallenge();
     status = irpc->generateCertificateRequest(
         /*test_mode=*/false, emptyKeys, eek, challenge, &verifiedDeviceInfo, &protectedData,
         &keysToSignMac);
     if (!status.isOk()) {
         std::cerr << "Bundle extraction failed for '" << componentName
                   << "'. Description: " << status.getDescription() << "." << std::endl;
         exit(-1);
     }
     return composeCertificateRequestV1(protectedData, verifiedDeviceInfo, challenge, keysToSignMac,
                                        irpc);
 }

 void selfTestGetCsrV1(std::string_view componentName, IRemotelyProvisionedComponent* irpc) {
     std::vector<uint8_t> keysToSignMac;
     std::vector<MacedPublicKey> emptyKeys;
     DeviceInfo verifiedDeviceInfo;
     ProtectedData protectedData;
     RpcHardwareInfo hwInfo;
     ::ndk::ScopedAStatus status = irpc->getHardwareInfo(&hwInfo);
     if (!status.isOk()) {
         std::cerr << "Failed to get hardware info for '" << componentName
                   << "'. Description: " << status.getDescription() << "." << std::endl;
         exit(-1);
     }

     const std::vector<uint8_t> eekId = {0, 1, 2, 3, 4, 5, 6, 7};
     ErrMsgOr<EekChain> eekChain = generateEekChain(hwInfo.supportedEekCurve, /*length=*/3, eekId);
     if (!eekChain) {
         std::cerr << "Error generating test EEK certificate chain: " << eekChain.message();
         exit(-1);
     }
     const std::vector<uint8_t> challenge = generateChallenge();
     status = irpc->generateCertificateRequest(
         /*test_mode=*/true, emptyKeys, eekChain->chain, challenge, &verifiedDeviceInfo,
         &protectedData, &keysToSignMac);
     if (!status.isOk()) {
         std::cerr << "Error generating test cert chain for '" << componentName
                   << "'. Description: " << status.getDescription() << "." << std::endl;
         exit(-1);
     }

     auto result = verifyFactoryProtectedData(verifiedDeviceInfo, /*keysToSign=*/{}, keysToSignMac,
                                              protectedData, *eekChain, eekId,
                                              hwInfo.supportedEekCurve, irpc, challenge);

     if (!result) {
         std::cerr << "Self test failed for IRemotelyProvisionedComponent '" << componentName
                   << "'. Error message: '" << result.message() << "'." << std::endl;
         exit(-1);
     }
 }

 CborResult<Array> composeCertificateRequestV3(const std::vector<uint8_t>& csr) {
     const std::string kFingerprintProp = "ro.build.fingerprint";

     auto [parsedCsr, _, csrErrMsg] = cppbor::parse(csr);
     if (!parsedCsr) {
         return {nullptr, csrErrMsg};
     }
     if (!parsedCsr->asArray()) {
         return {nullptr, "CSR is not a CBOR array."};
     }

     if (!::android::base::WaitForPropertyCreation(kFingerprintProp)) {
         return {nullptr, "Unable to read build fingerprint"};
     }

     Map unverifiedDeviceInfo =
         Map().add("fingerprint", ::android::base::GetProperty(kFingerprintProp, /*default=*/""));
     parsedCsr->asArray()->add(std::move(unverifiedDeviceInfo));
     return {std::unique_ptr<Array>(parsedCsr.release()->asArray()), ""};
 }

 CborResult<cppbor::Array> getCsrV3(std::string_view componentName,
                                    IRemotelyProvisionedComponent* irpc, bool selfTest) {
     std::vector<uint8_t> csr;
     std::vector<MacedPublicKey> emptyKeys;
     const std::vector<uint8_t> challenge = generateChallenge();

     auto status = irpc->generateCertificateRequestV2(emptyKeys, challenge, &csr);
     if (!status.isOk()) {
         std::cerr << "Bundle extraction failed for '" << componentName
                   << "'. Description: " << status.getDescription() << "." << std::endl;
         exit(-1);
     }

     if (selfTest) {
         auto result = verifyFactoryCsr(/*keysToSign=*/cppbor::Array(), csr, irpc, challenge);
         if (!result) {
             std::cerr << "Self test failed for IRemotelyProvisionedComponent '" << componentName
                       << "'. Error message: '" << result.message() << "'." << std::endl;
             exit(-1);
         }
     }

     return composeCertificateRequestV3(csr);
 }

 CborResult<Array> getCsr(std::string_view componentName, IRemotelyProvisionedComponent* irpc,
                          bool selfTest) {
     RpcHardwareInfo hwInfo;
     auto status = irpc->getHardwareInfo(&hwInfo);
     if (!status.isOk()) {
         std::cerr << "Failed to get hardware info for '" << componentName
                   << "'. Description: " << status.getDescription() << "." << std::endl;
         exit(-1);
     }

     if (hwInfo.versionNumber < kVersionWithoutSuperencryption) {
         if (selfTest) {
             selfTestGetCsrV1(componentName, irpc);
         }
         return getCsrV1(componentName, irpc);
     } else {
         return getCsrV3(componentName, irpc, selfTest);
     }
 }
	/*
	* Copyright 2022 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 "rkp_factory_extraction_lib.h"

	#include <aidl/android/hardware/security/keymint/IRemotelyProvisionedComponent.h>
	#include <android-base/properties.h>
	#include <android/binder_manager.h>
	#include <cppbor.h>
	#include <cstddef>
	#include <cstdint>
	#include <cstring>
	#include <iterator>
	#include <keymaster/cppcose/cppcose.h>
	#include <openssl/base64.h>
	#include <remote_prov/remote_prov_utils.h>
	#include <sys/random.h>

	#include <memory>
	#include <optional>
	#include <string>
	#include <string_view>
	#include <vector>

	#include "cppbor_parse.h"

	using aidl::android::hardware::security::keymint::DeviceInfo;
	using aidl::android::hardware::security::keymint::IRemotelyProvisionedComponent;
	using aidl::android::hardware::security::keymint::MacedPublicKey;
	using aidl::android::hardware::security::keymint::ProtectedData;
	using aidl::android::hardware::security::keymint::RpcHardwareInfo;
	using aidl::android::hardware::security::keymint::remote_prov::EekChain;
	using aidl::android::hardware::security::keymint::remote_prov::generateEekChain;
	using aidl::android::hardware::security::keymint::remote_prov::getProdEekChain;
	using aidl::android::hardware::security::keymint::remote_prov::jsonEncodeCsrWithBuild;
	using aidl::android::hardware::security::keymint::remote_prov::parseAndValidateFactoryDeviceInfo;
	using aidl::android::hardware::security::keymint::remote_prov::verifyFactoryCsr;
	using aidl::android::hardware::security::keymint::remote_prov::verifyFactoryProtectedData;

	using namespace cppbor;
	using namespace cppcose;

	constexpr size_t kVersionWithoutSuperencryption = 3;

	std::string toBase64(const std::vector<uint8_t>& buffer) {
	size_t base64Length;
	int rc = EVP_EncodedLength(&base64Length, buffer.size());
	if (!rc) {
	std::cerr << "Error getting base64 length. Size overflow?" << std::endl;
	exit(-1);
	}

	std::string base64(base64Length, ' ');
	rc = EVP_EncodeBlock(reinterpret_cast<uint8_t*>(base64.data()), buffer.data(), buffer.size());
	++rc; // Account for NUL, which BoringSSL does not for some reason.
	if (rc != base64Length) {
	std::cerr << "Error writing base64. Expected " << base64Length
	<< " bytes to be written, but " << rc << " bytes were actually written."
	<< std::endl;
	exit(-1);
	}

	// BoringSSL automatically adds a NUL -- remove it from the string data
	base64.pop_back();

	return base64;
	}

	std::vector<uint8_t> generateChallenge() {
	std::vector<uint8_t> challenge(kChallengeSize);

	ssize_t bytesRemaining = static_cast<ssize_t>(challenge.size());
	uint8_t* writePtr = challenge.data();
	while (bytesRemaining > 0) {
	int bytesRead = getrandom(writePtr, bytesRemaining, /flags=/0);
	if (bytesRead < 0) {
	if (errno == EINTR) {
	continue;
	} else {
	std::cerr << errno << ": " << strerror(errno) << std::endl;
	exit(-1);
	}
	}
	bytesRemaining -= bytesRead;
	writePtr += bytesRead;
	}

	return challenge;
	}

	CborResult<Array> composeCertificateRequestV1(const ProtectedData& protectedData,
	const DeviceInfo& verifiedDeviceInfo,
	const std::vector<uint8_t>& challenge,
	const std::vector<uint8_t>& keysToSignMac,
	IRemotelyProvisionedComponent* provisionable) {
	Array macedKeysToSign = Array()
	.add(Map().add(1, 5).encode()) // alg: hmac-sha256
	.add(Map()) // empty unprotected headers
	.add(Null()) // nil for the payload
	.add(keysToSignMac); // MAC as returned from the HAL

	ErrMsgOr<std::unique_ptr<Map>> parsedVerifiedDeviceInfo =
	parseAndValidateFactoryDeviceInfo(verifiedDeviceInfo.deviceInfo, provisionable);
	if (!parsedVerifiedDeviceInfo) {
	return {nullptr, parsedVerifiedDeviceInfo.moveMessage()};
	}

	auto [parsedProtectedData, ignore2, errMsg] = parse(protectedData.protectedData);
	if (!parsedProtectedData) {
	std::cerr << "Error parsing protected data: '" << errMsg << "'" << std::endl;
	return {nullptr, errMsg};
	}

	Array deviceInfo = Array().add(parsedVerifiedDeviceInfo.moveValue()).add(Map());

	auto certificateRequest = std::make_unique<Array>();
	(*certificateRequest)
	.add(std::move(deviceInfo))
	.add(challenge)
	.add(std::move(parsedProtectedData))
	.add(std::move(macedKeysToSign));
	return {std::move(certificateRequest), ""};
	}

	CborResult<Array> getCsrV1(std::string_view componentName, IRemotelyProvisionedComponent* irpc) {
	std::vector<uint8_t> keysToSignMac;
	std::vector<MacedPublicKey> emptyKeys;
	DeviceInfo verifiedDeviceInfo;
	ProtectedData protectedData;
	RpcHardwareInfo hwInfo;
	::ndk::ScopedAStatus status = irpc->getHardwareInfo(&hwInfo);
	if (!status.isOk()) {
	std::cerr << "Failed to get hardware info for '" << componentName
	<< "'. Description: " << status.getDescription() << "." << std::endl;
	exit(-1);
	}

	const std::vector<uint8_t> eek = getProdEekChain(hwInfo.supportedEekCurve);
	const std::vector<uint8_t> challenge = generateChallenge();
	status = irpc->generateCertificateRequest(
	/test_mode=/false, emptyKeys, eek, challenge, &verifiedDeviceInfo, &protectedData,
	&keysToSignMac);
	if (!status.isOk()) {
	std::cerr << "Bundle extraction failed for '" << componentName
	<< "'. Description: " << status.getDescription() << "." << std::endl;
	exit(-1);
	}
	return composeCertificateRequestV1(protectedData, verifiedDeviceInfo, challenge, keysToSignMac,
	irpc);
	}

	void selfTestGetCsrV1(std::string_view componentName, IRemotelyProvisionedComponent* irpc) {
	std::vector<uint8_t> keysToSignMac;
	std::vector<MacedPublicKey> emptyKeys;
	DeviceInfo verifiedDeviceInfo;
	ProtectedData protectedData;
	RpcHardwareInfo hwInfo;
	::ndk::ScopedAStatus status = irpc->getHardwareInfo(&hwInfo);
	if (!status.isOk()) {
	std::cerr << "Failed to get hardware info for '" << componentName
	<< "'. Description: " << status.getDescription() << "." << std::endl;
	exit(-1);
	}

	const std::vector<uint8_t> eekId = {0, 1, 2, 3, 4, 5, 6, 7};
	ErrMsgOr<EekChain> eekChain = generateEekChain(hwInfo.supportedEekCurve, /length=/3, eekId);
	if (!eekChain) {
	std::cerr << "Error generating test EEK certificate chain: " << eekChain.message();
	exit(-1);
	}
	const std::vector<uint8_t> challenge = generateChallenge();
	status = irpc->generateCertificateRequest(
	/test_mode=/true, emptyKeys, eekChain->chain, challenge, &verifiedDeviceInfo,
	&protectedData, &keysToSignMac);
	if (!status.isOk()) {
	std::cerr << "Error generating test cert chain for '" << componentName
	<< "'. Description: " << status.getDescription() << "." << std::endl;
	exit(-1);
	}

	auto result = verifyFactoryProtectedData(verifiedDeviceInfo, /keysToSign=/{}, keysToSignMac,
	protectedData, *eekChain, eekId,
	hwInfo.supportedEekCurve, irpc, challenge);

	if (!result) {
	std::cerr << "Self test failed for IRemotelyProvisionedComponent '" << componentName
	<< "'. Error message: '" << result.message() << "'." << std::endl;
	exit(-1);
	}
	}

	CborResult<Array> composeCertificateRequestV3(const std::vector<uint8_t>& csr) {
	const std::string kFingerprintProp = "ro.build.fingerprint";

	auto [parsedCsr, _, csrErrMsg] = cppbor::parse(csr);
	if (!parsedCsr) {
	return {nullptr, csrErrMsg};
	}
	if (!parsedCsr->asArray()) {
	return {nullptr, "CSR is not a CBOR array."};
	}

	if (!::android::base::WaitForPropertyCreation(kFingerprintProp)) {
	return {nullptr, "Unable to read build fingerprint"};
	}

	Map unverifiedDeviceInfo =
	Map().add("fingerprint", ::android::base::GetProperty(kFingerprintProp, /default=/""));
	parsedCsr->asArray()->add(std::move(unverifiedDeviceInfo));
	return {std::unique_ptr<Array>(parsedCsr.release()->asArray()), ""};
	}

	CborResult<cppbor::Array> getCsrV3(std::string_view componentName,
	IRemotelyProvisionedComponent* irpc, bool selfTest) {
	std::vector<uint8_t> csr;
	std::vector<MacedPublicKey> emptyKeys;
	const std::vector<uint8_t> challenge = generateChallenge();

	auto status = irpc->generateCertificateRequestV2(emptyKeys, challenge, &csr);
	if (!status.isOk()) {
	std::cerr << "Bundle extraction failed for '" << componentName
	<< "'. Description: " << status.getDescription() << "." << std::endl;
	exit(-1);
	}

	if (selfTest) {
	auto result = verifyFactoryCsr(/keysToSign=/cppbor::Array(), csr, irpc, challenge);
	if (!result) {
	std::cerr << "Self test failed for IRemotelyProvisionedComponent '" << componentName
	<< "'. Error message: '" << result.message() << "'." << std::endl;
	exit(-1);
	}
	}

	return composeCertificateRequestV3(csr);
	}

	CborResult<Array> getCsr(std::string_view componentName, IRemotelyProvisionedComponent* irpc,
	bool selfTest) {
	RpcHardwareInfo hwInfo;
	auto status = irpc->getHardwareInfo(&hwInfo);
	if (!status.isOk()) {
	std::cerr << "Failed to get hardware info for '" << componentName
	<< "'. Description: " << status.getDescription() << "." << std::endl;
	exit(-1);
	}

	if (hwInfo.versionNumber < kVersionWithoutSuperencryption) {
	if (selfTest) {
	selfTestGetCsrV1(componentName, irpc);
	}
	return getCsrV1(componentName, irpc);
	} else {
	return getCsrV3(componentName, irpc, selfTest);
	}
	}