gatekeeperd/gatekeeperd.cpp - android_system_core - Gitiles

 /*
  * Copyright (C) 2015 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 "gatekeeperd"

 #include <android/service/gatekeeper/BnGateKeeperService.h>
 #include <gatekeeper/GateKeeperResponse.h>

 #include <endian.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <memory>

 #include <android-base/logging.h>
 #include <android-base/properties.h>
 #include <android/binder_ibinder.h>
 #include <android/binder_manager.h>
 #include <binder/IPCThreadState.h>
 #include <binder/IServiceManager.h>
 #include <binder/PermissionCache.h>
 #include <gatekeeper/password_handle.h>  // for password_handle_t
 #include <hardware/hw_auth_token.h>
 #include <libgsi/libgsi.h>
 #include <log/log.h>
 #include <utils/String16.h>

 #include <aidl/android/hardware/security/keymint/HardwareAuthToken.h>
 #include <aidl/android/security/authorization/IKeystoreAuthorization.h>
 #include <android/hardware/gatekeeper/1.0/IGatekeeper.h>
 #include <hidl/HidlSupport.h>

 using android::sp;
 using android::hardware::Return;
 using android::hardware::gatekeeper::V1_0::GatekeeperResponse;
 using android::hardware::gatekeeper::V1_0::GatekeeperStatusCode;
 using android::hardware::gatekeeper::V1_0::IGatekeeper;

 using ::android::binder::Status;
 using ::android::service::gatekeeper::BnGateKeeperService;
 using GKResponse = ::android::service::gatekeeper::GateKeeperResponse;
 using GKResponseCode = ::android::service::gatekeeper::ResponseCode;
 using ::aidl::android::hardware::security::keymint::HardwareAuthenticatorType;
 using ::aidl::android::hardware::security::keymint::HardwareAuthToken;
 using ::aidl::android::security::authorization::IKeystoreAuthorization;

 namespace android {

 static const String16 KEYGUARD_PERMISSION("android.permission.ACCESS_KEYGUARD_SECURE_STORAGE");
 static const String16 DUMP_PERMISSION("android.permission.DUMP");

 class GateKeeperProxy : public BnGateKeeperService {
   public:
     GateKeeperProxy() {
         clear_state_if_needed_done = false;
         hw_device = IGatekeeper::getService();
         is_running_gsi = android::base::GetBoolProperty(android::gsi::kGsiBootedProp, false);

         if (!hw_device) {
             LOG(ERROR) << "Could not find Gatekeeper device, which makes me very sad.";
         }
     }

     virtual ~GateKeeperProxy() {}

     void store_sid(uint32_t userId, uint64_t sid) {
         char filename[21];
         snprintf(filename, sizeof(filename), "%u", userId);
         int fd = open(filename, O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR);
         if (fd < 0) {
             ALOGE("could not open file: %s: %s", filename, strerror(errno));
             return;
         }
         write(fd, &sid, sizeof(sid));
         close(fd);
     }

     void clear_state_if_needed() {
         if (clear_state_if_needed_done) {
             return;
         }

         if (mark_cold_boot() && !is_running_gsi) {
             ALOGI("cold boot: clearing state");
             if (hw_device) {
                 hw_device->deleteAllUsers([](const GatekeeperResponse&) {});
             }
         }

         clear_state_if_needed_done = true;
     }

     bool mark_cold_boot() {
         const char* filename = ".coldboot";
         if (access(filename, F_OK) == -1) {
             int fd = open(filename, O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR);
             if (fd < 0) {
                 ALOGE("could not open file: %s : %s", filename, strerror(errno));
                 return false;
             }
             close(fd);
             return true;
         }
         return false;
     }

     void maybe_store_sid(uint32_t userId, uint64_t sid) {
         char filename[21];
         snprintf(filename, sizeof(filename), "%u", userId);
         if (access(filename, F_OK) == -1) {
             store_sid(userId, sid);
         }
     }

     uint64_t read_sid(uint32_t userId) {
         char filename[21];
         uint64_t sid;
         snprintf(filename, sizeof(filename), "%u", userId);
         int fd = open(filename, O_RDONLY);
         if (fd < 0) return 0;
         read(fd, &sid, sizeof(sid));
         close(fd);
         return sid;
     }

     void clear_sid(uint32_t userId) {
         char filename[21];
         snprintf(filename, sizeof(filename), "%u", userId);
         if (remove(filename) < 0) {
             ALOGE("%s: could not remove file [%s], attempting 0 write", __func__, strerror(errno));
             store_sid(userId, 0);
         }
     }

     // This should only be called on userIds being passed to the GateKeeper HAL. It ensures that
     // secure storage shared across a GSI image and a host image will not overlap.
     uint32_t adjust_userId(uint32_t userId) {
         static constexpr uint32_t kGsiOffset = 1000000;
         CHECK(userId < kGsiOffset);
         CHECK(hw_device != nullptr);
         if (is_running_gsi) {
             return userId + kGsiOffset;
         }
         return userId;
     }

 #define GK_ERROR *gkResponse = GKResponse::error(), Status::ok()

     Status enroll(int32_t userId, const std::optional<std::vector<uint8_t>>& currentPasswordHandle,
                   const std::optional<std::vector<uint8_t>>& currentPassword,
                   const std::vector<uint8_t>& desiredPassword, GKResponse* gkResponse) override {
         IPCThreadState* ipc = IPCThreadState::self();
         const int calling_pid = ipc->getCallingPid();
         const int calling_uid = ipc->getCallingUid();
         if (!PermissionCache::checkPermission(KEYGUARD_PERMISSION, calling_pid, calling_uid)) {
             return GK_ERROR;
         }

         // Make sure to clear any state from before factory reset as soon as a credential is
         // enrolled (which may happen during device setup).
         clear_state_if_needed();

         // need a desired password to enroll
         if (desiredPassword.size() == 0) return GK_ERROR;

         if (!hw_device) {
             LOG(ERROR) << "has no HAL to talk to";
             return GK_ERROR;
         }

         android::hardware::hidl_vec<uint8_t> curPwdHandle;
         android::hardware::hidl_vec<uint8_t> curPwd;

         if (currentPasswordHandle && currentPassword) {
             if (currentPasswordHandle->size() != sizeof(gatekeeper::password_handle_t)) {
                 LOG(INFO) << "Password handle has wrong length";
                 return GK_ERROR;
             }
             curPwdHandle.setToExternal(const_cast<uint8_t*>(currentPasswordHandle->data()),
                                        currentPasswordHandle->size());
             curPwd.setToExternal(const_cast<uint8_t*>(currentPassword->data()),
                                  currentPassword->size());
         }

         android::hardware::hidl_vec<uint8_t> newPwd;
         newPwd.setToExternal(const_cast<uint8_t*>(desiredPassword.data()), desiredPassword.size());

         uint32_t hw_userId = adjust_userId(userId);
         Return<void> hwRes = hw_device->enroll(
                 hw_userId, curPwdHandle, curPwd, newPwd,
                 [&gkResponse](const GatekeeperResponse& rsp) {
                     if (rsp.code >= GatekeeperStatusCode::STATUS_OK) {
                         *gkResponse = GKResponse::ok({rsp.data.begin(), rsp.data.end()});
                     } else if (rsp.code == GatekeeperStatusCode::ERROR_RETRY_TIMEOUT &&
                                rsp.timeout > 0) {
                         *gkResponse = GKResponse::retry(rsp.timeout);
                     } else {
                         *gkResponse = GKResponse::error();
                     }
                 });
         if (!hwRes.isOk()) {
             LOG(ERROR) << "enroll transaction failed";
             return GK_ERROR;
         }

         if (gkResponse->response_code() == GKResponseCode::OK && !gkResponse->should_reenroll()) {
             if (gkResponse->payload().size() != sizeof(gatekeeper::password_handle_t)) {
                 LOG(ERROR) << "HAL returned password handle of invalid length "
                            << gkResponse->payload().size();
                 return GK_ERROR;
             }

             const gatekeeper::password_handle_t* handle =
                     reinterpret_cast<const gatekeeper::password_handle_t*>(
                             gkResponse->payload().data());
             store_sid(userId, handle->user_id);

             GKResponse verifyResponse;
             // immediately verify this password so we don't ask the user to enter it again
             // if they just created it.
             auto status = verify(userId, gkResponse->payload(), desiredPassword, &verifyResponse);
             if (!status.isOk() || verifyResponse.response_code() != GKResponseCode::OK) {
                 LOG(ERROR) << "Failed to verify password after enrolling";
             }
         }

         return Status::ok();
     }

     Status verify(int32_t userId, const ::std::vector<uint8_t>& enrolledPasswordHandle,
                   const ::std::vector<uint8_t>& providedPassword, GKResponse* gkResponse) override {
         return verifyChallenge(userId, 0 /* challenge */, enrolledPasswordHandle, providedPassword,
                                gkResponse);
     }

     Status verifyChallenge(int32_t userId, int64_t challenge,
                            const std::vector<uint8_t>& enrolledPasswordHandle,
                            const std::vector<uint8_t>& providedPassword,
                            GKResponse* gkResponse) override {
         IPCThreadState* ipc = IPCThreadState::self();
         const int calling_pid = ipc->getCallingPid();
         const int calling_uid = ipc->getCallingUid();
         if (!PermissionCache::checkPermission(KEYGUARD_PERMISSION, calling_pid, calling_uid)) {
             return GK_ERROR;
         }

         // can't verify if we're missing either param
         if (enrolledPasswordHandle.size() == 0 || providedPassword.size() == 0) return GK_ERROR;

         if (!hw_device) return GK_ERROR;

         if (enrolledPasswordHandle.size() != sizeof(gatekeeper::password_handle_t)) {
             LOG(INFO) << "Password handle has wrong length";
             return GK_ERROR;
         }
         const gatekeeper::password_handle_t* handle =
                 reinterpret_cast<const gatekeeper::password_handle_t*>(
                         enrolledPasswordHandle.data());

         uint32_t hw_userId = adjust_userId(userId);
         android::hardware::hidl_vec<uint8_t> curPwdHandle;
         curPwdHandle.setToExternal(const_cast<uint8_t*>(enrolledPasswordHandle.data()),
                                    enrolledPasswordHandle.size());
         android::hardware::hidl_vec<uint8_t> enteredPwd;
         enteredPwd.setToExternal(const_cast<uint8_t*>(providedPassword.data()),
                                  providedPassword.size());

         Return<void> hwRes = hw_device->verify(
                 hw_userId, challenge, curPwdHandle, enteredPwd,
                 [&gkResponse](const GatekeeperResponse& rsp) {
                     if (rsp.code >= GatekeeperStatusCode::STATUS_OK) {
                         *gkResponse = GKResponse::ok(
                                 {rsp.data.begin(), rsp.data.end()},
                                 rsp.code == GatekeeperStatusCode::STATUS_REENROLL /* reenroll */);
                     } else if (rsp.code == GatekeeperStatusCode::ERROR_RETRY_TIMEOUT) {
                         *gkResponse = GKResponse::retry(rsp.timeout);
                     } else {
                         *gkResponse = GKResponse::error();
                     }
                 });

         if (!hwRes.isOk()) {
             LOG(ERROR) << "verify transaction failed";
             return GK_ERROR;
         }

         if (gkResponse->response_code() == GKResponseCode::OK) {
             if (gkResponse->payload().size() != 0) {
                 // try to connect to IKeystoreAuthorization AIDL service first.
                 AIBinder* authzAIBinder =
                         AServiceManager_getService("android.security.authorization");
                 ::ndk::SpAIBinder authzBinder(authzAIBinder);
                 auto authzService = IKeystoreAuthorization::fromBinder(authzBinder);
                 if (authzService) {
                     if (gkResponse->payload().size() != sizeof(hw_auth_token_t)) {
                         LOG(ERROR) << "Incorrect size of AuthToken payload.";
                         return GK_ERROR;
                     }

                     const hw_auth_token_t* hwAuthToken =
                             reinterpret_cast<const hw_auth_token_t*>(gkResponse->payload().data());
                     HardwareAuthToken authToken;

                     authToken.timestamp.milliSeconds = betoh64(hwAuthToken->timestamp);
                     authToken.challenge = hwAuthToken->challenge;
                     authToken.userId = hwAuthToken->user_id;
                     authToken.authenticatorId = hwAuthToken->authenticator_id;
                     authToken.authenticatorType = static_cast<HardwareAuthenticatorType>(
                             betoh32(hwAuthToken->authenticator_type));
                     authToken.mac.assign(&hwAuthToken->hmac[0], &hwAuthToken->hmac[32]);
                     auto result = authzService->addAuthToken(authToken);
                     if (!result.isOk()) {
                         LOG(ERROR) << "Failure in sending AuthToken to AuthorizationService.";
                         return GK_ERROR;
                     }
                 } else {
                     LOG(ERROR) << "Cannot deliver auth token. Unable to communicate with "
                                   "Keystore.";
                     return GK_ERROR;
                 }
             }

             maybe_store_sid(userId, handle->user_id);
         }

         return Status::ok();
     }

     Status getSecureUserId(int32_t userId, int64_t* sid) override {
         *sid = read_sid(userId);
         return Status::ok();
     }

     Status clearSecureUserId(int32_t userId) override {
         IPCThreadState* ipc = IPCThreadState::self();
         const int calling_pid = ipc->getCallingPid();
         const int calling_uid = ipc->getCallingUid();
         if (!PermissionCache::checkPermission(KEYGUARD_PERMISSION, calling_pid, calling_uid)) {
             ALOGE("%s: permission denied for [%d:%d]", __func__, calling_pid, calling_uid);
             return Status::ok();
         }
         clear_sid(userId);

         if (hw_device) {
             uint32_t hw_userId = adjust_userId(userId);
             hw_device->deleteUser(hw_userId, [](const GatekeeperResponse&) {});
         }
         return Status::ok();
     }

     Status reportDeviceSetupComplete() override {
         IPCThreadState* ipc = IPCThreadState::self();
         const int calling_pid = ipc->getCallingPid();
         const int calling_uid = ipc->getCallingUid();
         if (!PermissionCache::checkPermission(KEYGUARD_PERMISSION, calling_pid, calling_uid)) {
             ALOGE("%s: permission denied for [%d:%d]", __func__, calling_pid, calling_uid);
             return Status::ok();
         }

         clear_state_if_needed();
         return Status::ok();
     }

     status_t dump(int fd, const Vector<String16>&) override {
         IPCThreadState* ipc = IPCThreadState::self();
         const int pid = ipc->getCallingPid();
         const int uid = ipc->getCallingUid();
         if (!PermissionCache::checkPermission(DUMP_PERMISSION, pid, uid)) {
             return PERMISSION_DENIED;
         }

         if (hw_device == NULL) {
             const char* result = "Device not available";
             write(fd, result, strlen(result) + 1);
         } else {
             const char* result = "OK";
             write(fd, result, strlen(result) + 1);
         }

         return OK;
     }

   private:
     sp<IGatekeeper> hw_device;

     bool clear_state_if_needed_done;
     bool is_running_gsi;
 };
 }  // namespace android

 int main(int argc, char* argv[]) {
     ALOGI("Starting gatekeeperd...");
     if (argc < 2) {
         ALOGE("A directory must be specified!");
         return 1;
     }
     if (chdir(argv[1]) == -1) {
         ALOGE("chdir: %s: %s", argv[1], strerror(errno));
         return 1;
     }

     android::sp<android::IServiceManager> sm = android::defaultServiceManager();
     android::sp<android::GateKeeperProxy> proxy = new android::GateKeeperProxy();
     android::status_t ret = sm->addService(
             android::String16("android.service.gatekeeper.IGateKeeperService"), proxy);
     if (ret != android::OK) {
         ALOGE("Couldn't register binder service!");
         return -1;
     }

     /*
      * We're the only thread in existence, so we're just going to process
      * Binder transaction as a single-threaded program.
      */
     android::IPCThreadState::self()->joinThreadPool();
     return 0;
 }
	/*
	* Copyright (C) 2015 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 "gatekeeperd"

	#include <android/service/gatekeeper/BnGateKeeperService.h>
	#include <gatekeeper/GateKeeperResponse.h>

	#include <endian.h>
	#include <errno.h>
	#include <fcntl.h>
	#include <unistd.h>
	#include <memory>

	#include <android-base/logging.h>
	#include <android-base/properties.h>
	#include <android/binder_ibinder.h>
	#include <android/binder_manager.h>
	#include <binder/IPCThreadState.h>
	#include <binder/IServiceManager.h>
	#include <binder/PermissionCache.h>
	#include <gatekeeper/password_handle.h> // for password_handle_t
	#include <hardware/hw_auth_token.h>
	#include <libgsi/libgsi.h>
	#include <log/log.h>
	#include <utils/String16.h>

	#include <aidl/android/hardware/security/keymint/HardwareAuthToken.h>
	#include <aidl/android/security/authorization/IKeystoreAuthorization.h>
	#include <android/hardware/gatekeeper/1.0/IGatekeeper.h>
	#include <hidl/HidlSupport.h>

	using android::sp;
	using android::hardware::Return;
	using android::hardware::gatekeeper::V1_0::GatekeeperResponse;
	using android::hardware::gatekeeper::V1_0::GatekeeperStatusCode;
	using android::hardware::gatekeeper::V1_0::IGatekeeper;

	using ::android::binder::Status;
	using ::android::service::gatekeeper::BnGateKeeperService;
	using GKResponse = ::android::service::gatekeeper::GateKeeperResponse;
	using GKResponseCode = ::android::service::gatekeeper::ResponseCode;
	using ::aidl::android::hardware::security::keymint::HardwareAuthenticatorType;
	using ::aidl::android::hardware::security::keymint::HardwareAuthToken;
	using ::aidl::android::security::authorization::IKeystoreAuthorization;

	namespace android {

	static const String16 KEYGUARD_PERMISSION("android.permission.ACCESS_KEYGUARD_SECURE_STORAGE");
	static const String16 DUMP_PERMISSION("android.permission.DUMP");

	class GateKeeperProxy : public BnGateKeeperService {
	public:
	GateKeeperProxy() {
	clear_state_if_needed_done = false;
	hw_device = IGatekeeper::getService();
	is_running_gsi = android::base::GetBoolProperty(android::gsi::kGsiBootedProp, false);

	if (!hw_device) {
	LOG(ERROR) << "Could not find Gatekeeper device, which makes me very sad.";
	}
	}

	virtual ~GateKeeperProxy() {}

	void store_sid(uint32_t userId, uint64_t sid) {
	char filename[21];
	snprintf(filename, sizeof(filename), "%u", userId);
	int fd = open(filename, O_WRONLY \| O_TRUNC \| O_CREAT, S_IRUSR \| S_IWUSR);
	if (fd < 0) {
	ALOGE("could not open file: %s: %s", filename, strerror(errno));
	return;
	}
	write(fd, &sid, sizeof(sid));
	close(fd);
	}

	void clear_state_if_needed() {
	if (clear_state_if_needed_done) {
	return;
	}

	if (mark_cold_boot() && !is_running_gsi) {
	ALOGI("cold boot: clearing state");
	if (hw_device) {
	hw_device->deleteAllUsers([](const GatekeeperResponse&) {});
	}
	}

	clear_state_if_needed_done = true;
	}

	bool mark_cold_boot() {
	const char* filename = ".coldboot";
	if (access(filename, F_OK) == -1) {
	int fd = open(filename, O_WRONLY \| O_TRUNC \| O_CREAT, S_IRUSR \| S_IWUSR);
	if (fd < 0) {
	ALOGE("could not open file: %s : %s", filename, strerror(errno));
	return false;
	}
	close(fd);
	return true;
	}
	return false;
	}

	void maybe_store_sid(uint32_t userId, uint64_t sid) {
	char filename[21];
	snprintf(filename, sizeof(filename), "%u", userId);
	if (access(filename, F_OK) == -1) {
	store_sid(userId, sid);
	}
	}

	uint64_t read_sid(uint32_t userId) {
	char filename[21];
	uint64_t sid;
	snprintf(filename, sizeof(filename), "%u", userId);
	int fd = open(filename, O_RDONLY);
	if (fd < 0) return 0;
	read(fd, &sid, sizeof(sid));
	close(fd);
	return sid;
	}

	void clear_sid(uint32_t userId) {
	char filename[21];
	snprintf(filename, sizeof(filename), "%u", userId);
	if (remove(filename) < 0) {
	ALOGE("%s: could not remove file [%s], attempting 0 write", __func__, strerror(errno));
	store_sid(userId, 0);
	}
	}

	// This should only be called on userIds being passed to the GateKeeper HAL. It ensures that
	// secure storage shared across a GSI image and a host image will not overlap.
	uint32_t adjust_userId(uint32_t userId) {
	static constexpr uint32_t kGsiOffset = 1000000;
	CHECK(userId < kGsiOffset);
	CHECK(hw_device != nullptr);
	if (is_running_gsi) {
	return userId + kGsiOffset;
	}
	return userId;
	}

	#define GK_ERROR *gkResponse = GKResponse::error(), Status::ok()

	Status enroll(int32_t userId, const std::optional<std::vector<uint8_t>>& currentPasswordHandle,
	const std::optional<std::vector<uint8_t>>& currentPassword,
	const std::vector<uint8_t>& desiredPassword, GKResponse* gkResponse) override {
	IPCThreadState* ipc = IPCThreadState::self();
	const int calling_pid = ipc->getCallingPid();
	const int calling_uid = ipc->getCallingUid();
	if (!PermissionCache::checkPermission(KEYGUARD_PERMISSION, calling_pid, calling_uid)) {
	return GK_ERROR;
	}

	// Make sure to clear any state from before factory reset as soon as a credential is
	// enrolled (which may happen during device setup).
	clear_state_if_needed();

	// need a desired password to enroll
	if (desiredPassword.size() == 0) return GK_ERROR;

	if (!hw_device) {
	LOG(ERROR) << "has no HAL to talk to";
	return GK_ERROR;
	}

	android::hardware::hidl_vec<uint8_t> curPwdHandle;
	android::hardware::hidl_vec<uint8_t> curPwd;

	if (currentPasswordHandle && currentPassword) {
	if (currentPasswordHandle->size() != sizeof(gatekeeper::password_handle_t)) {
	LOG(INFO) << "Password handle has wrong length";
	return GK_ERROR;
	}
	curPwdHandle.setToExternal(const_cast<uint8_t*>(currentPasswordHandle->data()),
	currentPasswordHandle->size());
	curPwd.setToExternal(const_cast<uint8_t*>(currentPassword->data()),
	currentPassword->size());
	}

	android::hardware::hidl_vec<uint8_t> newPwd;
	newPwd.setToExternal(const_cast<uint8_t*>(desiredPassword.data()), desiredPassword.size());

	uint32_t hw_userId = adjust_userId(userId);
	Return<void> hwRes = hw_device->enroll(
	hw_userId, curPwdHandle, curPwd, newPwd,
	[&gkResponse](const GatekeeperResponse& rsp) {
	if (rsp.code >= GatekeeperStatusCode::STATUS_OK) {
	*gkResponse = GKResponse::ok({rsp.data.begin(), rsp.data.end()});
	} else if (rsp.code == GatekeeperStatusCode::ERROR_RETRY_TIMEOUT &&
	rsp.timeout > 0) {
	*gkResponse = GKResponse::retry(rsp.timeout);
	} else {
	*gkResponse = GKResponse::error();
	}
	});
	if (!hwRes.isOk()) {
	LOG(ERROR) << "enroll transaction failed";
	return GK_ERROR;
	}

	if (gkResponse->response_code() == GKResponseCode::OK && !gkResponse->should_reenroll()) {
	if (gkResponse->payload().size() != sizeof(gatekeeper::password_handle_t)) {
	LOG(ERROR) << "HAL returned password handle of invalid length "
	<< gkResponse->payload().size();
	return GK_ERROR;
	}

	const gatekeeper::password_handle_t* handle =
	reinterpret_cast<const gatekeeper::password_handle_t*>(
	gkResponse->payload().data());
	store_sid(userId, handle->user_id);

	GKResponse verifyResponse;
	// immediately verify this password so we don't ask the user to enter it again
	// if they just created it.
	auto status = verify(userId, gkResponse->payload(), desiredPassword, &verifyResponse);
	if (!status.isOk() \|\| verifyResponse.response_code() != GKResponseCode::OK) {
	LOG(ERROR) << "Failed to verify password after enrolling";
	}
	}

	return Status::ok();
	}

	Status verify(int32_t userId, const ::std::vector<uint8_t>& enrolledPasswordHandle,
	const ::std::vector<uint8_t>& providedPassword, GKResponse* gkResponse) override {
	return verifyChallenge(userId, 0 /* challenge */, enrolledPasswordHandle, providedPassword,
	gkResponse);
	}

	Status verifyChallenge(int32_t userId, int64_t challenge,
	const std::vector<uint8_t>& enrolledPasswordHandle,
	const std::vector<uint8_t>& providedPassword,
	GKResponse* gkResponse) override {
	IPCThreadState* ipc = IPCThreadState::self();
	const int calling_pid = ipc->getCallingPid();
	const int calling_uid = ipc->getCallingUid();
	if (!PermissionCache::checkPermission(KEYGUARD_PERMISSION, calling_pid, calling_uid)) {
	return GK_ERROR;
	}

	// can't verify if we're missing either param
	if (enrolledPasswordHandle.size() == 0 \|\| providedPassword.size() == 0) return GK_ERROR;

	if (!hw_device) return GK_ERROR;

	if (enrolledPasswordHandle.size() != sizeof(gatekeeper::password_handle_t)) {
	LOG(INFO) << "Password handle has wrong length";
	return GK_ERROR;
	}
	const gatekeeper::password_handle_t* handle =
	reinterpret_cast<const gatekeeper::password_handle_t*>(
	enrolledPasswordHandle.data());

	uint32_t hw_userId = adjust_userId(userId);
	android::hardware::hidl_vec<uint8_t> curPwdHandle;
	curPwdHandle.setToExternal(const_cast<uint8_t*>(enrolledPasswordHandle.data()),
	enrolledPasswordHandle.size());
	android::hardware::hidl_vec<uint8_t> enteredPwd;
	enteredPwd.setToExternal(const_cast<uint8_t*>(providedPassword.data()),
	providedPassword.size());

	Return<void> hwRes = hw_device->verify(
	hw_userId, challenge, curPwdHandle, enteredPwd,
	[&gkResponse](const GatekeeperResponse& rsp) {
	if (rsp.code >= GatekeeperStatusCode::STATUS_OK) {
	*gkResponse = GKResponse::ok(
	{rsp.data.begin(), rsp.data.end()},
	rsp.code == GatekeeperStatusCode::STATUS_REENROLL /* reenroll */);
	} else if (rsp.code == GatekeeperStatusCode::ERROR_RETRY_TIMEOUT) {
	*gkResponse = GKResponse::retry(rsp.timeout);
	} else {
	*gkResponse = GKResponse::error();
	}
	});

	if (!hwRes.isOk()) {
	LOG(ERROR) << "verify transaction failed";
	return GK_ERROR;
	}

	if (gkResponse->response_code() == GKResponseCode::OK) {
	if (gkResponse->payload().size() != 0) {
	// try to connect to IKeystoreAuthorization AIDL service first.
	AIBinder* authzAIBinder =
	AServiceManager_getService("android.security.authorization");
	::ndk::SpAIBinder authzBinder(authzAIBinder);
	auto authzService = IKeystoreAuthorization::fromBinder(authzBinder);
	if (authzService) {
	if (gkResponse->payload().size() != sizeof(hw_auth_token_t)) {
	LOG(ERROR) << "Incorrect size of AuthToken payload.";
	return GK_ERROR;
	}

	const hw_auth_token_t* hwAuthToken =
	reinterpret_cast<const hw_auth_token_t*>(gkResponse->payload().data());
	HardwareAuthToken authToken;

	authToken.timestamp.milliSeconds = betoh64(hwAuthToken->timestamp);
	authToken.challenge = hwAuthToken->challenge;
	authToken.userId = hwAuthToken->user_id;
	authToken.authenticatorId = hwAuthToken->authenticator_id;
	authToken.authenticatorType = static_cast<HardwareAuthenticatorType>(
	betoh32(hwAuthToken->authenticator_type));
	authToken.mac.assign(&hwAuthToken->hmac[0], &hwAuthToken->hmac[32]);
	auto result = authzService->addAuthToken(authToken);
	if (!result.isOk()) {
	LOG(ERROR) << "Failure in sending AuthToken to AuthorizationService.";
	return GK_ERROR;
	}
	} else {
	LOG(ERROR) << "Cannot deliver auth token. Unable to communicate with "
	"Keystore.";
	return GK_ERROR;
	}
	}

	maybe_store_sid(userId, handle->user_id);
	}

	return Status::ok();
	}

	Status getSecureUserId(int32_t userId, int64_t* sid) override {
	*sid = read_sid(userId);
	return Status::ok();
	}

	Status clearSecureUserId(int32_t userId) override {
	IPCThreadState* ipc = IPCThreadState::self();
	const int calling_pid = ipc->getCallingPid();
	const int calling_uid = ipc->getCallingUid();
	if (!PermissionCache::checkPermission(KEYGUARD_PERMISSION, calling_pid, calling_uid)) {
	ALOGE("%s: permission denied for [%d:%d]", __func__, calling_pid, calling_uid);
	return Status::ok();
	}
	clear_sid(userId);

	if (hw_device) {
	uint32_t hw_userId = adjust_userId(userId);
	hw_device->deleteUser(hw_userId, [](const GatekeeperResponse&) {});
	}
	return Status::ok();
	}

	Status reportDeviceSetupComplete() override {
	IPCThreadState* ipc = IPCThreadState::self();
	const int calling_pid = ipc->getCallingPid();
	const int calling_uid = ipc->getCallingUid();
	if (!PermissionCache::checkPermission(KEYGUARD_PERMISSION, calling_pid, calling_uid)) {
	ALOGE("%s: permission denied for [%d:%d]", __func__, calling_pid, calling_uid);
	return Status::ok();
	}

	clear_state_if_needed();
	return Status::ok();
	}

	status_t dump(int fd, const Vector<String16>&) override {
	IPCThreadState* ipc = IPCThreadState::self();
	const int pid = ipc->getCallingPid();
	const int uid = ipc->getCallingUid();
	if (!PermissionCache::checkPermission(DUMP_PERMISSION, pid, uid)) {
	return PERMISSION_DENIED;
	}

	if (hw_device == NULL) {
	const char* result = "Device not available";
	write(fd, result, strlen(result) + 1);
	} else {
	const char* result = "OK";
	write(fd, result, strlen(result) + 1);
	}

	return OK;
	}

	private:
	sp<IGatekeeper> hw_device;

	bool clear_state_if_needed_done;
	bool is_running_gsi;
	};
	} // namespace android

	int main(int argc, char* argv[]) {
	ALOGI("Starting gatekeeperd...");
	if (argc < 2) {
	ALOGE("A directory must be specified!");
	return 1;
	}
	if (chdir(argv[1]) == -1) {
	ALOGE("chdir: %s: %s", argv[1], strerror(errno));
	return 1;
	}

	android::sp<android::IServiceManager> sm = android::defaultServiceManager();
	android::sp<android::GateKeeperProxy> proxy = new android::GateKeeperProxy();
	android::status_t ret = sm->addService(
	android::String16("android.service.gatekeeper.IGateKeeperService"), proxy);
	if (ret != android::OK) {
	ALOGE("Couldn't register binder service!");
	return -1;
	}

	/*
	* We're the only thread in existence, so we're just going to process
	* Binder transaction as a single-threaded program.
	*/
	android::IPCThreadState::self()->joinThreadPool();
	return 0;
	}