Expose more functionality from hwtrust (b85a71d7) · Commits · e / os / android_hardware_interfaces

security/keymint/support/include/remote_prov/remote_prov_utils.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -29,6 +29,11 @@ namespace aidl::android::hardware::security::keymint::remote_prov {
		using bytevec = std::vector<uint8_t>;
		using namespace cppcose;

		constexpr std::string_view kErrorChallengeMismatch = "challenges do not match";
		constexpr std::string_view kErrorUdsCertsAreRequired = "UdsCerts are required";
		constexpr std::string_view kErrorKeysToSignMismatch = "KeysToSign do not match";
		constexpr std::string_view kErrorDiceChainIsDegenerate = "DICE chain is degenerate";

		extern bytevec kTestMacKey;

		// The Google root key for the Endpoint Encryption Key chain, encoded as COSE_Sign1

security/keymint/support/remote_prov_utils.cpp

+63 −338

Original line number	Diff line number	Diff line
		@@ -123,37 +123,6 @@ ErrMsgOr<std::tuple<bytevec, bytevec>> getAffineCoordinates(const bytevec& pubKe
		return std::make_tuple(std::move(pubX), std::move(pubY));
		}

		ErrMsgOr<bytevec> getRawPublicKey(const EVP_PKEY_Ptr& pubKey) {
		if (pubKey.get() == nullptr) {
		return "pkey is null.";
		}
		int keyType = EVP_PKEY_base_id(pubKey.get());
		switch (keyType) {
		case EVP_PKEY_EC: {
		int nid = EVP_PKEY_bits(pubKey.get()) == 384 ? NID_secp384r1 : NID_X9_62_prime256v1;
		auto ecKey = EC_KEY_Ptr(EVP_PKEY_get1_EC_KEY(pubKey.get()));
		if (ecKey.get() == nullptr) {
		return "Failed to get ec key";
		}
		return ecKeyGetPublicKey(ecKey.get(), nid);
		}
		case EVP_PKEY_ED25519: {
		bytevec rawPubKey;
		size_t rawKeySize = 0;
		if (!EVP_PKEY_get_raw_public_key(pubKey.get(), NULL, &rawKeySize)) {
		return "Failed to get raw public key.";
		}
		rawPubKey.resize(rawKeySize);
		if (!EVP_PKEY_get_raw_public_key(pubKey.get(), rawPubKey.data(), &rawKeySize)) {
		return "Failed to get raw public key.";
		}
		return rawPubKey;
		}
		default:
		return "Unknown key type.";
		}
		}

		ErrMsgOr<std::tuple<bytevec, bytevec>> generateEc256KeyPair() {
		auto ec_key = EC_KEY_Ptr(EC_KEY_new());
		if (ec_key.get() == nullptr) {
		@@ -166,7 +135,7 @@ ErrMsgOr<std::tuple<bytevec, bytevec>> generateEc256KeyPair() {
		}

		if (EC_KEY_set_group(ec_key.get(), group.get()) != 1 \|\|
		EC_KEY_generate_key(ec_key.get()) != 1 \|\| EC_KEY_check_key(ec_key.get()) < 0) {
		EC_KEY_generate_key(ec_key.get()) != 1 \|\| EC_KEY_check_key(ec_key.get()) != 1) {
		return "Error generating key";
		}

		@@ -331,17 +300,22 @@ bytevec getProdEekChain(int32_t supportedEekCurve) {
		return chain.encode();
		}

		bool maybeOverrideAllowAnyMode(bool allowAnyMode) {
		// Use ro.build.type instead of ro.debuggable because ro.debuggable=1 for VTS testing
		std::string build_type = ::android::base::GetProperty("ro.build.type", "");
		if (!build_type.empty() && build_type != "user") {
		return true;
		}
		return allowAnyMode;
		}

		ErrMsgOr<std::vector<BccEntryData>> validateBcc(const cppbor::Array* bcc,
		hwtrust::DiceChain::Kind kind, bool allowAnyMode,
		bool allowDegenerate,
		const std::string& instanceName) {
		auto encodedBcc = bcc->encode();

		// Use ro.build.type instead of ro.debuggable because ro.debuggable=1 for VTS testing
		std::string build_type = ::android::base::GetProperty("ro.build.type", "");
		if (!build_type.empty() && build_type != "user") {
		allowAnyMode = true;
		}
		allowAnyMode = maybeOverrideAllowAnyMode(allowAnyMode);

		auto chain =
		hwtrust::DiceChain::Verify(encodedBcc, kind, allowAnyMode, deviceSuffix(instanceName));
		@@ -779,230 +753,6 @@ ErrMsgOr<std::vector<BccEntryData>> verifyProductionProtectedData(
		/isFactory=/false, allowAnyMode);
		}

		ErrMsgOr<X509_Ptr> parseX509Cert(const std::vector<uint8_t>& cert) {
		CRYPTO_BUFFER_Ptr certBuf(CRYPTO_BUFFER_new(cert.data(), cert.size(), nullptr));
		if (!certBuf.get()) {
		return "Failed to create crypto buffer.";
		}
		X509_Ptr result(X509_parse_from_buffer(certBuf.get()));
		if (!result.get()) {
		return "Failed to parse certificate.";
		}
		return result;
		}

		std::string getX509IssuerName(const X509_Ptr& cert) {
		char* name = X509_NAME_oneline(X509_get_issuer_name(cert.get()), nullptr, 0);
		std::string result(name);
		OPENSSL_free(name);
		return result;
		}

		std::string getX509SubjectName(const X509_Ptr& cert) {
		char* name = X509_NAME_oneline(X509_get_subject_name(cert.get()), nullptr, 0);
		std::string result(name);
		OPENSSL_free(name);
		return result;
		}

		// Validates the certificate chain and returns the leaf public key.
		ErrMsgOr<bytevec> validateCertChain(const cppbor::Array& chain) {
		bytevec rawPubKey;
		for (size_t i = 0; i < chain.size(); ++i) {
		// Root must be self-signed.
		size_t signingCertIndex = (i > 0) ? i - 1 : i;
		auto& keyCertItem = chain[i];
		auto& signingCertItem = chain[signingCertIndex];
		if (!keyCertItem \|\| !keyCertItem->asBstr()) {
		return "Key certificate must be a Bstr.";
		}
		if (!signingCertItem \|\| !signingCertItem->asBstr()) {
		return "Signing certificate must be a Bstr.";
		}

		auto keyCert = parseX509Cert(keyCertItem->asBstr()->value());
		if (!keyCert) {
		return keyCert.message();
		}
		auto signingCert = parseX509Cert(signingCertItem->asBstr()->value());
		if (!signingCert) {
		return signingCert.message();
		}

		EVP_PKEY_Ptr pubKey(X509_get_pubkey(keyCert->get()));
		if (!pubKey.get()) {
		return "Failed to get public key.";
		}
		EVP_PKEY_Ptr signingPubKey(X509_get_pubkey(signingCert->get()));
		if (!signingPubKey.get()) {
		return "Failed to get signing public key.";
		}

		if (!X509_verify(keyCert->get(), signingPubKey.get())) {
		return "Verification of certificate " + std::to_string(i) +
		" faile. OpenSSL error string: " + ERR_error_string(ERR_get_error(), NULL);
		}

		auto certIssuer = getX509IssuerName(*keyCert);
		auto signerSubj = getX509SubjectName(*signingCert);
		if (certIssuer != signerSubj) {
		return "Certificate " + std::to_string(i) + " has wrong issuer. Signer subject is " +
		signerSubj + " Issuer subject is " + certIssuer;
		}
		if (i == chain.size() - 1) {
		auto key = getRawPublicKey(pubKey);
		if (!key) return key.moveMessage();
		rawPubKey = key.moveValue();
		}
		}
		return rawPubKey;
		}

		std::optional<std::string> validateUdsCerts(const cppbor::Map& udsCerts,
		const bytevec& udsCoseKeyBytes) {
		for (const auto& [signerName, udsCertChain] : udsCerts) {
		if (!signerName \|\| !signerName->asTstr()) {
		return "Signer Name must be a Tstr.";
		}
		if (!udsCertChain \|\| !udsCertChain->asArray()) {
		return "UDS certificate chain must be an Array.";
		}
		if (udsCertChain->asArray()->size() < 2) {
		return "UDS certificate chain must have at least two entries: root and leaf.";
		}

		auto leafPubKey = validateCertChain(*udsCertChain->asArray());
		if (!leafPubKey) {
		return leafPubKey.message();
		}
		auto coseKey = CoseKey::parse(udsCoseKeyBytes);
		if (!coseKey) {
		return coseKey.moveMessage();
		}
		auto curve = coseKey->getIntValue(CoseKey::CURVE);
		if (!curve) {
		return "CoseKey must contain curve.";
		}
		bytevec udsPub;
		if (curve == CoseKeyCurve::P256 \|\| curve == CoseKeyCurve::P384) {
		auto pubKey = coseKey->getEcPublicKey();
		if (!pubKey) {
		return pubKey.moveMessage();
		}
		// convert public key to uncompressed form by prepending 0x04 at begin.
		pubKey->insert(pubKey->begin(), 0x04);
		udsPub = pubKey.moveValue();
		} else if (curve == CoseKeyCurve::ED25519) {
		auto& pubkey = coseKey->getMap().get(cppcose::CoseKey::PUBKEY_X);
		if (!pubkey \|\| !pubkey->asBstr()) {
		return "Invalid public key.";
		}
		udsPub = pubkey->asBstr()->value();
		} else {
		return "Unknown curve.";
		}
		if (*leafPubKey != udsPub) {
		return "Leaf public key in UDS certificate chain doesn't match UDS public key.";
		}
		}
		return std::nullopt;
		}

		ErrMsgOr<std::unique_ptr<cppbor::Array>> parseAndValidateCsrPayload(
		const cppbor::Array& keysToSign, const std::vector<uint8_t>& csrPayload,
		const RpcHardwareInfo& rpcHardwareInfo, bool isFactory) {
		auto [parsedCsrPayload, _, errMsg] = cppbor::parse(csrPayload);
		if (!parsedCsrPayload) {
		return errMsg;
		}

		std::unique_ptr<cppbor::Array> parsed(parsedCsrPayload.release()->asArray());
		if (!parsed) {
		return "CSR payload is not a CBOR array.";
		}

		if (parsed->size() != 4U) {
		return "CSR payload must contain version, certificate type, device info, keys. "
		"However, the parsed CSR payload has " +
		std::to_string(parsed->size()) + " entries.";
		}

		auto signedVersion = parsed->get(0)->asUint();
		auto signedCertificateType = parsed->get(1)->asTstr();
		auto signedDeviceInfo = parsed->get(2)->asMap();
		auto signedKeys = parsed->get(3)->asArray();

		if (!signedVersion \|\| signedVersion->value() != 3U) {
		return "CSR payload version must be an unsigned integer and must be equal to 3.";
		}
		if (!signedCertificateType) {
		// Certificate type is allowed to be extendend by vendor, i.e. we can't
		// enforce its value.
		return "Certificate type must be a Tstr.";
		}
		if (!signedDeviceInfo) {
		return "Device info must be an Map.";
		}
		if (!signedKeys) {
		return "Keys must be an Array.";
		}

		auto result =
		parseAndValidateDeviceInfo(signedDeviceInfo->encode(), rpcHardwareInfo, isFactory);
		if (!result) {
		return result.message();
		}

		if (signedKeys->encode() != keysToSign.encode()) {
		return "Signed keys do not match.";
		}

		return std::move(parsed);
		}

		ErrMsgOr<bytevec> parseAndValidateAuthenticatedRequestSignedPayload(
		const std::vector<uint8_t>& signedPayload, const std::vector<uint8_t>& challenge) {
		auto [parsedSignedPayload, _, errMsg] = cppbor::parse(signedPayload);
		if (!parsedSignedPayload) {
		return errMsg;
		}
		if (!parsedSignedPayload->asArray()) {
		return "SignedData payload is not a CBOR array.";
		}
		if (parsedSignedPayload->asArray()->size() != 2U) {
		return "SignedData payload must contain the challenge and request. However, the parsed "
		"SignedData payload has " +
		std::to_string(parsedSignedPayload->asArray()->size()) + " entries.";
		}

		auto signedChallenge = parsedSignedPayload->asArray()->get(0)->asBstr();
		auto signedRequest = parsedSignedPayload->asArray()->get(1)->asBstr();

		if (!signedChallenge) {
		return "Challenge must be a Bstr.";
		}

		if (challenge.size() > 64) {
		return "Challenge size must be between 0 and 64 bytes inclusive. "
		"However, challenge is " +
		std::to_string(challenge.size()) + " bytes long.";
		}

		auto challengeBstr = cppbor::Bstr(challenge);
		if (*signedChallenge != challengeBstr) {
		return "Signed challenge does not match."
		"\n Actual: " +
		cppbor::prettyPrint(signedChallenge->asBstr(), 64 /* maxBStrSize */) +
		"\nExpected: " + cppbor::prettyPrint(&challengeBstr, 64 /* maxBStrSize */);
		}

		if (!signedRequest) {
		return "Request must be a Bstr.";
		}

		return signedRequest->value();
		}

		ErrMsgOr<hwtrust::DiceChain::Kind> getDiceChainKind() {
		int vendor_api_level = ::android::base::GetIntProperty("ro.vendor.api_level", -1);
		if (vendor_api_level <= __ANDROID_API_T__) {
		@@ -1018,104 +768,79 @@ ErrMsgOr<hwtrust::DiceChain::Kind> getDiceChainKind() {
		}
		}

		ErrMsgOr<bytevec> parseAndValidateAuthenticatedRequest(const std::vector<uint8_t>& request,
		const std::vector<uint8_t>& challenge,
		const std::string& instanceName,
		bool allowAnyMode = false,
		bool allowDegenerate = true,
		bool requireUdsCerts = false) {
		auto [parsedRequest, _, csrErrMsg] = cppbor::parse(request);
		if (!parsedRequest) {
		return csrErrMsg;
		}
		if (!parsedRequest->asArray()) {
		return "AuthenticatedRequest is not a CBOR array.";
		ErrMsgOr<std::unique_ptr<cppbor::Array>> verifyCsr(
		const cppbor::Array& keysToSign, const std::vector<uint8_t>& encodedCsr,
		const RpcHardwareInfo& rpcHardwareInfo, const std::string& instanceName,
		const std::vector<uint8_t>& challenge, bool isFactory, bool allowAnyMode = false,
		bool allowDegenerate = true, bool requireUdsCerts = false) {
		if (rpcHardwareInfo.versionNumber != 3) {
		return "Remotely provisioned component version (" +
		std::to_string(rpcHardwareInfo.versionNumber) +
		") does not match expected version (3).";
		}
		if (parsedRequest->asArray()->size() != 4U) {
		return "AuthenticatedRequest must contain version, UDS certificates, DICE chain, and "
		"signed data. However, the parsed AuthenticatedRequest has " +
		std::to_string(parsedRequest->asArray()->size()) + " entries.";

		auto diceChainKind = getDiceChainKind();
		if (!diceChainKind) {
		return diceChainKind.message();
		}

		auto version = parsedRequest->asArray()->get(0)->asUint();
		auto udsCerts = parsedRequest->asArray()->get(1)->asMap();
		auto diceCertChain = parsedRequest->asArray()->get(2)->asArray();
		auto signedData = parsedRequest->asArray()->get(3)->asArray();
		allowAnyMode = maybeOverrideAllowAnyMode(allowAnyMode);

		if (!version \|\| version->value() != 1U) {
		return "AuthenticatedRequest version must be an unsigned integer and must be equal to 1.";
		}
		auto csr = hwtrust::Csr::validate(encodedCsr, *diceChainKind, isFactory, allowAnyMode,
		deviceSuffix(instanceName));

		if (!udsCerts) {
		return "AuthenticatedRequest UdsCerts must be a Map.";
		if (!csr.ok()) {
		return csr.error().message();
		}
		if (requireUdsCerts && udsCerts->size() == 0) {
		return "AuthenticatedRequest UdsCerts must not be empty.";

		if (!allowDegenerate) {
		auto diceChain = csr->getDiceChain();
		if (!diceChain.ok()) {
		return diceChain.error().message();
		}
		if (!diceCertChain) {
		return "AuthenticatedRequest DiceCertChain must be an Array.";

		if (!diceChain->IsProper()) {
		return kErrorDiceChainIsDegenerate;
		}
		if (!signedData) {
		return "AuthenticatedRequest SignedData must be an Array.";
		}

		// DICE chain is [ pubkey, + DiceChainEntry ].
		auto diceChainKind = getDiceChainKind();
		if (!diceChainKind) {
		return diceChainKind.message();
		if (requireUdsCerts && !csr->hasUdsCerts()) {
		return kErrorUdsCertsAreRequired;
		}

		auto diceContents =
		validateBcc(diceCertChain, *diceChainKind, allowAnyMode, allowDegenerate, instanceName);
		if (!diceContents) {
		return diceContents.message() + "\n" + prettyPrint(diceCertChain);
		auto equalChallenges = csr->compareChallenge(challenge);
		if (!equalChallenges.ok()) {
		return equalChallenges.error().message();
		}

		if (!diceCertChain->get(0)->asMap()) {
		return "AuthenticatedRequest The first entry in DiceCertChain must be a Map.";
		}
		auto udsPub = diceCertChain->get(0)->asMap()->encode();
		auto error = validateUdsCerts(*udsCerts, udsPub);
		if (error) {
		return *error;
		if (!*equalChallenges) {
		return kErrorChallengeMismatch;
		}

		if (diceContents->empty()) {
		return "AuthenticatedRequest DiceContents must not be empty.";
		}
		auto& kmDiceKey = diceContents->back().pubKey;
		auto signedPayload = verifyAndParseCoseSign1(signedData, kmDiceKey, /aad=/{});
		if (!signedPayload) {
		return signedPayload.message();
		auto equalKeysToSign = csr->compareKeysToSign(keysToSign.encode());
		if (!equalKeysToSign.ok()) {
		return equalKeysToSign.error().message();
		}

		auto payload = parseAndValidateAuthenticatedRequestSignedPayload(*signedPayload, challenge);
		if (!payload) {
		return payload.message();
		if (!*equalKeysToSign) {
		return kErrorKeysToSignMismatch;
		}

		return payload;
		auto csrPayload = csr->getCsrPayload();
		if (!csrPayload) {
		return csrPayload.error().message();
		}

		ErrMsgOr<std::unique_ptr<cppbor::Array>> verifyCsr(
		const cppbor::Array& keysToSign, const std::vector<uint8_t>& csr,
		const RpcHardwareInfo& rpcHardwareInfo, const std::string& instanceName,
		const std::vector<uint8_t>& challenge, bool isFactory, bool allowAnyMode = false,
		bool allowDegenerate = true, bool requireUdsCerts = false) {
		if (rpcHardwareInfo.versionNumber != 3) {
		return "Remotely provisioned component version (" +
		std::to_string(rpcHardwareInfo.versionNumber) +
		") does not match expected version (3).";
		auto [csrPayloadDecoded, _, errMsg] = cppbor::parse(*csrPayload);
		if (!csrPayloadDecoded) {
		return errMsg;
		}

		auto csrPayload = parseAndValidateAuthenticatedRequest(
		csr, challenge, instanceName, allowAnyMode, allowDegenerate, requireUdsCerts);

		if (!csrPayload) {
		return csrPayload.message();
		if (!csrPayloadDecoded->asArray()) {
		return "CSR payload is not an array.";
		}

		return parseAndValidateCsrPayload(keysToSign, *csrPayload, rpcHardwareInfo, isFactory);
		return std::unique_ptr<cppbor::Array>(csrPayloadDecoded.release()->asArray());
		}

		ErrMsgOr<std::unique_ptr<cppbor::Array>> verifyFactoryCsr(
		@@ -1143,8 +868,8 @@ ErrMsgOr<bool> isCsrWithProperDiceChain(const std::vector<uint8_t>& encodedCsr,
		return diceChainKind.message();
		}

		auto csr = hwtrust::Csr::validate(encodedCsr, diceChainKind, false /allowAnyMode*/,
		deviceSuffix(instanceName));
		auto csr = hwtrust::Csr::validate(encodedCsr, diceChainKind, false /isFactory*/,
		false /allowAnyMode/, deviceSuffix(instanceName));
		if (!csr.ok()) {
		return csr.error().message();
		}

security/keymint/support/remote_prov_utils_test.cpp

+96 −8

File changed.

Preview size limit exceeded, changes collapsed.

security/rkp/aidl/vts/functional/VtsRemotelyProvisionedComponentTests.cpp

+1 −0

Original line number	Diff line number	Diff line
		@@ -999,6 +999,7 @@ TEST_P(CertificateRequestV2Test, DeviceInfo) {

		std::unique_ptr<cppbor::Array> csrPayload = std::move(*result);
		ASSERT_TRUE(csrPayload);
		ASSERT_TRUE(csrPayload->size() > 2);

		auto deviceInfo = csrPayload->get(2)->asMap();
		ASSERT_TRUE(deviceInfo);