Merge "C++ AIDL on-device GateKeeper / SharedSecret impl" into main (e23e4504) · Commits · e / os / android_hardware_interfaces

gatekeeper/aidl/software/Android.bp

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		package {
		// See: http://go/android-license-faq
		// A large-scale-change added 'default_applicable_licenses' to import
		// all of the 'license_kinds' from "hardware_interfaces_license"
		// to get the below license kinds:
		// SPDX-license-identifier-Apache-2.0
		default_applicable_licenses: ["hardware_interfaces_license"],
		}

		cc_binary {
		name: "android.hardware.gatekeeper-service.nonsecure",
		cflags: [
		"-fvisibility=hidden",
		"-Wall",
		"-Werror",
		],
		installable: false, // installed in APEX
		relative_install_path: "hw",
		shared_libs: [
		"android.hardware.gatekeeper-V1-ndk",
		"android.hardware.security.sharedsecret-V1-ndk",
		"lib_android_keymaster_keymint_utils",
		"libbase",
		"libbinder_ndk",
		"libcrypto",
		"libcutils",
		"libgatekeeper",
		"libhardware",
		"libkeymaster_portable",
		"liblog",
		"libutils",
		],
		srcs: [
		"GateKeeper.cpp",
		"SharedSecret.cpp",
		"service.cpp",
		],
		static_libs: ["libscrypt_static"],
		vendor: true,
		}

		prebuilt_etc {
		name: "gatekeeper_nonsecure_vintf",
		srcs: [
		"android.hardware.gatekeeper-service.nonsecure.xml",
		"android.hardware.security.sharedsecret-gatekeeper.xml",
		],
		sub_dir: "vintf",
		installable: false,
		}

		prebuilt_etc {
		name: "android.hardware.gatekeeper-service.nonsecure.rc",
		src: "android.hardware.gatekeeper-service.nonsecure.rc",
		installable: false,
		}

		apex {
		name: "com.android.hardware.gatekeeper.nonsecure",
		binaries: ["android.hardware.gatekeeper-service.nonsecure"],
		certificate: ":com.google.cf.apex.certificate",
		file_contexts: "file_contexts",
		key: "com.google.cf.apex.key",
		manifest: "manifest.json",
		prebuilts: [
		"gatekeeper_nonsecure_vintf",
		"android.hardware.gatekeeper-service.nonsecure.rc",
		],
		updatable: false,
		vendor: true,
		}

gatekeeper/aidl/software/GateKeeper.cpp

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		/*
		* Copyright (C) 2016 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.
		*/
		#define LOG_TAG "android.hardware.gatekeeper-service.nonsecure"

		#include <endian.h>

		#include <android-base/logging.h>

		#include "GateKeeper.h"

		using ::gatekeeper::EnrollRequest;
		using ::gatekeeper::EnrollResponse;
		using ::gatekeeper::ERROR_NONE;
		using ::gatekeeper::ERROR_RETRY;
		using ::gatekeeper::SizedBuffer;
		using ::gatekeeper::VerifyRequest;
		using ::gatekeeper::VerifyResponse;

		namespace aidl::android::hardware::gatekeeper {

		SizedBuffer vec2sized_buffer(const std::vector<uint8_t>& vec) {
		if (vec.size() == 0 \|\| vec.size() > std::numeric_limits<uint32_t>::max()) {
		return {};
		}
		auto unused = new uint8_t[vec.size()];
		std::copy(vec.begin(), vec.end(), unused);
		return {unused, static_cast<uint32_t>(vec.size())};
		}

		void sizedBuffer2AidlHWToken(SizedBuffer& buffer,
		android::hardware::security::keymint::HardwareAuthToken* aidlToken) {
		const hw_auth_token_t* authToken =
		reinterpret_cast<const hw_auth_token_t*>(buffer.Data<uint8_t>());
		aidlToken->challenge = authToken->challenge;
		aidlToken->userId = authToken->user_id;
		aidlToken->authenticatorId = authToken->authenticator_id;
		// these are in network order: translate to host
		aidlToken->authenticatorType =
		static_cast<android::hardware::security::keymint::HardwareAuthenticatorType>(
		be32toh(authToken->authenticator_type));
		aidlToken->timestamp.milliSeconds = be64toh(authToken->timestamp);
		aidlToken->mac.insert(aidlToken->mac.begin(), std::begin(authToken->hmac),
		std::end(authToken->hmac));
		}

		SoftGateKeeperDevice::SoftGateKeeperDevice(::gatekeeper::SoftGateKeeper& impl) : impl_(impl) {}

		::ndk::ScopedAStatus SoftGateKeeperDevice::enroll(int32_t uid,
		const std::vector<uint8_t>& currentPasswordHandle,
		const std::vector<uint8_t>& currentPassword,
		const std::vector<uint8_t>& desiredPassword,
		GatekeeperEnrollResponse* rsp) {
		if (desiredPassword.size() == 0) {
		LOG(ERROR) << "Desired password size is 0";
		return ndk::ScopedAStatus(AStatus_fromServiceSpecificError(ERROR_GENERAL_FAILURE));
		}

		if (currentPasswordHandle.size() > 0) {
		if (currentPasswordHandle.size() != sizeof(::gatekeeper::password_handle_t)) {
		LOG(ERROR) << "Password handle has wrong length";
		return ndk::ScopedAStatus(AStatus_fromServiceSpecificError(ERROR_GENERAL_FAILURE));
		}
		}

		EnrollRequest request(uid, vec2sized_buffer(currentPasswordHandle),
		vec2sized_buffer(desiredPassword), vec2sized_buffer(currentPassword));
		EnrollResponse response;
		impl_.Enroll(request, &response);
		if (response.error == ERROR_RETRY) {
		LOG(ERROR) << "Enroll response has a retry error";
		*rsp = {ERROR_RETRY_TIMEOUT, static_cast<int32_t>(response.retry_timeout), 0, {}};
		return ndk::ScopedAStatus::ok();
		} else if (response.error != ERROR_NONE) {
		LOG(ERROR) << "Enroll response has an error: " << response.error;
		return ndk::ScopedAStatus(AStatus_fromServiceSpecificError(ERROR_GENERAL_FAILURE));
		} else {
		const ::gatekeeper::password_handle_t* password_handle =
		response.enrolled_password_handle.Data<::gatekeeper::password_handle_t>();
		*rsp = {STATUS_OK,
		0,
		static_cast<int64_t>(password_handle->user_id),
		{response.enrolled_password_handle.Data<uint8_t>(),
		(response.enrolled_password_handle.Data<uint8_t>() +
		response.enrolled_password_handle.size())}};
		}
		return ndk::ScopedAStatus::ok();
		}

		::ndk::ScopedAStatus SoftGateKeeperDevice::verify(
		int32_t uid, int64_t challenge, const std::vector<uint8_t>& enrolledPasswordHandle,
		const std::vector<uint8_t>& providedPassword, GatekeeperVerifyResponse* rsp) {
		if (enrolledPasswordHandle.size() == 0) {
		LOG(ERROR) << "Enrolled password size is 0";
		return ndk::ScopedAStatus(AStatus_fromServiceSpecificError(ERROR_GENERAL_FAILURE));
		}

		if (enrolledPasswordHandle.size() > 0) {
		if (enrolledPasswordHandle.size() != sizeof(::gatekeeper::password_handle_t)) {
		LOG(ERROR) << "Password handle has wrong length";
		return ndk::ScopedAStatus(AStatus_fromServiceSpecificError(ERROR_GENERAL_FAILURE));
		}
		}

		VerifyRequest request(uid, challenge, vec2sized_buffer(enrolledPasswordHandle),
		vec2sized_buffer(providedPassword));
		VerifyResponse response;
		impl_.Verify(request, &response);

		if (response.error == ERROR_RETRY) {
		LOG(ERROR) << "Verify request response gave retry error";
		*rsp = {ERROR_RETRY_TIMEOUT, static_cast<int32_t>(response.retry_timeout), {}};
		return ndk::ScopedAStatus::ok();
		} else if (response.error != ERROR_NONE) {
		LOG(ERROR) << "Verify request response gave error: " << response.error;
		return ndk::ScopedAStatus(AStatus_fromServiceSpecificError(ERROR_GENERAL_FAILURE));
		} else {
		// On Success, return GatekeeperVerifyResponse with Success Status, timeout{0} and
		// valid HardwareAuthToken.
		*rsp = {response.request_reenroll ? STATUS_REENROLL : STATUS_OK, 0, {}};
		// Convert the hw_auth_token_t to HardwareAuthToken in the response.
		sizedBuffer2AidlHWToken(response.auth_token, &rsp->hardwareAuthToken);
		}
		return ndk::ScopedAStatus::ok();
		}

		::ndk::ScopedAStatus SoftGateKeeperDevice::deleteUser(int32_t /uid/) {
		LOG(ERROR) << "deleteUser is unimplemented";
		return ndk::ScopedAStatus(AStatus_fromServiceSpecificError(ERROR_NOT_IMPLEMENTED));
		}

		::ndk::ScopedAStatus SoftGateKeeperDevice::deleteAllUsers() {
		LOG(ERROR) << "deleteAllUsers is unimplemented";
		return ndk::ScopedAStatus(AStatus_fromServiceSpecificError(ERROR_NOT_IMPLEMENTED));
		}

		} // namespace aidl::android::hardware::gatekeeper

gatekeeper/aidl/software/GateKeeper.h

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		/*
		* Copyright (C) 2014 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.
		*/
		#pragma once

		#include <aidl/android/hardware/gatekeeper/BnGatekeeper.h>
		#include <gatekeeper/gatekeeper_messages.h>

		#include "SoftGateKeeper.h"

		namespace aidl::android::hardware::gatekeeper {

		class SoftGateKeeperDevice : public BnGatekeeper {
		public:
		SoftGateKeeperDevice(::gatekeeper::SoftGateKeeper&);
		/**
		* Enrolls password_payload, which should be derived from a user selected pin
		* or password, with the authentication factor private key used only for
		* enrolling authentication factor data.
		*
		* Returns: 0 on success or an error code less than 0 on error.
		* On error, enrolled_password_handle will not be allocated.
		*/
		::ndk::ScopedAStatus enroll(int32_t uid, const std::vector<uint8_t>& currentPasswordHandle,
		const std::vector<uint8_t>& currentPassword,
		const std::vector<uint8_t>& desiredPassword,
		GatekeeperEnrollResponse* _aidl_return) override;
		/**
		* Verifies provided_password matches enrolled_password_handle.
		*
		* Implementations of this module may retain the result of this call
		* to attest to the recency of authentication.
		*
		* On success, writes the address of a verification token to auth_token,
		* usable to attest password verification to other trusted services. Clients
		* may pass NULL for this value.
		*
		* Returns: 0 on success or an error code less than 0 on error
		* On error, verification token will not be allocated
		*/
		::ndk::ScopedAStatus verify(int32_t uid, int64_t challenge,
		const std::vector<uint8_t>& enrolledPasswordHandle,
		const std::vector<uint8_t>& providedPassword,
		GatekeeperVerifyResponse* _aidl_return) override;

		::ndk::ScopedAStatus deleteAllUsers() override;

		::ndk::ScopedAStatus deleteUser(int32_t uid) override;

		private:
		::gatekeeper::SoftGateKeeper& impl_;
		};

		} // namespace aidl::android::hardware::gatekeeper

gatekeeper/aidl/software/SharedSecret.cpp

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		/*
		* Copyright 2024, 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 "SharedSecret.h"

		#include <algorithm>
		#include <cstring>
		#include <mutex>
		#include <vector>

		#include <openssl/rand.h>

		#include <KeyMintUtils.h>
		#include <aidl/android/hardware/security/sharedsecret/BnSharedSecret.h>
		#include <aidl/android/hardware/security/sharedsecret/SharedSecretParameters.h>
		#include <android-base/logging.h>
		#include <keymaster/android_keymaster_messages.h>
		#include <keymaster/android_keymaster_utils.h>
		#include <keymaster/km_openssl/ckdf.h>
		#include <keymaster/km_openssl/hmac.h>

		namespace aidl::android::hardware::security::sharedsecret {

		::ndk::ScopedAStatus SoftSharedSecret::getSharedSecretParameters(
		SharedSecretParameters* out_params) {
		std::lock_guard lock(mutex_);
		if (seed_.empty()) {
		seed_.resize(32, 0);
		}
		out_params->seed = seed_;
		if (nonce_.empty()) {
		nonce_.resize(32, 0);
		RAND_bytes(nonce_.data(), 32);
		}
		out_params->nonce = nonce_;
		LOG(INFO) << "Presented shared secret parameters with seed size " << out_params->seed.size()
		<< " and nonce size " << out_params->nonce.size();
		return ::ndk::ScopedAStatus::ok();
		}

		::ndk::ScopedAStatus SoftSharedSecret::computeSharedSecret(
		const std::vector<SharedSecretParameters>& params, std::vector<uint8_t>* sharing_check) {
		std::lock_guard lock(mutex_);
		LOG(INFO) << "Computing shared secret";
		// Reimplemented based on SoftKeymasterEnforcement, which does not expose
		// enough functionality to satisfy the GateKeeper interface
		keymaster::KeymasterKeyBlob key_agreement_key;
		if (key_agreement_key.Reset(32) == nullptr) {
		LOG(ERROR) << "key agreement key memory allocation failed";
		return keymint::km_utils::kmError2ScopedAStatus(KM_ERROR_MEMORY_ALLOCATION_FAILED);
		}
		// Matching:
		// - kFakeAgreementKey in system/keymaster/km_openssl/soft_keymaster_enforcement.cpp
		// - Keys::kak in hardware/interfaces/security/keymint/aidl/default/ta/soft.rs
		std::memset(key_agreement_key.writable_data(), 0, 32);
		keymaster::KeymasterBlob label((uint8_t*)KEY_AGREEMENT_LABEL, strlen(KEY_AGREEMENT_LABEL));
		if (label.data == nullptr) {
		LOG(ERROR) << "label memory allocation failed";
		return keymint::km_utils::kmError2ScopedAStatus(KM_ERROR_MEMORY_ALLOCATION_FAILED);
		}

		static_assert(sizeof(keymaster_blob_t) == sizeof(keymaster::KeymasterBlob));

		bool found_mine = false;
		std::vector<keymaster::KeymasterBlob> context_blobs;
		for (const auto& param : params) {
		auto& seed_blob = context_blobs.emplace_back();
		if (seed_blob.Reset(param.seed.size()) == nullptr) {
		LOG(ERROR) << "seed memory allocation failed";
		return keymint::km_utils::kmError2ScopedAStatus(KM_ERROR_MEMORY_ALLOCATION_FAILED);
		}
		std::copy(param.seed.begin(), param.seed.end(), seed_blob.writable_data());
		auto& nonce_blob = context_blobs.emplace_back();
		if (nonce_blob.Reset(param.nonce.size()) == nullptr) {
		LOG(ERROR) << "Nonce memory allocation failed";
		return keymint::km_utils::kmError2ScopedAStatus(KM_ERROR_MEMORY_ALLOCATION_FAILED);
		}
		std::copy(param.nonce.begin(), param.nonce.end(), nonce_blob.writable_data());
		if (param.seed == seed_ && param.nonce == nonce_) {
		found_mine = true;
		}
		}
		if (!found_mine) {
		LOG(ERROR) << "Did not receive my own shared secret parameter back";
		return keymint::km_utils::kmError2ScopedAStatus(KM_ERROR_INVALID_ARGUMENT);
		}
		auto context_blobs_ptr = reinterpret_cast<keymaster_blob_t*>(context_blobs.data());
		if (hmac_key_.Reset(32) == nullptr) {
		LOG(ERROR) << "hmac key allocation failed";
		return keymint::km_utils::kmError2ScopedAStatus(KM_ERROR_MEMORY_ALLOCATION_FAILED);
		}
		auto error = keymaster::ckdf(key_agreement_key, label, context_blobs_ptr, context_blobs.size(),
		&hmac_key_);
		if (error != KM_ERROR_OK) {
		LOG(ERROR) << "CKDF failed";
		return keymint::km_utils::kmError2ScopedAStatus(error);
		}

		keymaster::HmacSha256 hmac_impl;
		if (!hmac_impl.Init(hmac_key_.key_material, hmac_key_.key_material_size)) {
		LOG(ERROR) << "hmac initialization failed";
		return ::ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
		}
		sharing_check->clear();
		sharing_check->resize(32, 0);
		if (!hmac_impl.Sign((const uint8_t*)KEY_CHECK_LABEL, strlen(KEY_CHECK_LABEL),
		sharing_check->data(), sharing_check->size())) {
		return ::ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
		}
		return ::ndk::ScopedAStatus::ok();
		}

		keymaster::KeymasterKeyBlob SoftSharedSecret::HmacKey() const {
		std::lock_guard lock(mutex_);
		return hmac_key_;
		}

		} // namespace aidl::android::hardware::security::sharedsecret

gatekeeper/aidl/software/SharedSecret.h

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		/*
		* Copyright 2020, 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.
		*/

		#pragma once

		#include <cstdint>
		#include <mutex>

		#include <aidl/android/hardware/security/sharedsecret/BnSharedSecret.h>
		#include <aidl/android/hardware/security/sharedsecret/SharedSecretParameters.h>
		#include <keymaster/km_openssl/soft_keymaster_enforcement.h>

		namespace aidl::android::hardware::security::sharedsecret {

		class SoftSharedSecret : public BnSharedSecret {
		public:
		::ndk::ScopedAStatus getSharedSecretParameters(SharedSecretParameters* params) override;
		::ndk::ScopedAStatus computeSharedSecret(const std::vector<SharedSecretParameters>& params,
		std::vector<uint8_t>* sharingCheck) override;

		keymaster::KeymasterKeyBlob HmacKey() const;

		private:
		mutable std::mutex mutex_;
		std::vector<std::uint8_t> seed_;
		std::vector<std::uint8_t> nonce_;
		keymaster::KeymasterKeyBlob hmac_key_;
		};

		} // namespace aidl::android::hardware::security::sharedsecret