hw/usb/u2f-emulated.c - qemu - Git at Google

 /*
  * U2F USB Emulated device.
  *
  * Copyright (c) 2020 César Belley <cesar.belley@lse.epita.fr>
  * Written by César Belley <cesar.belley@lse.epita.fr>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */

 #include "qemu/osdep.h"
 #include "qemu/module.h"
 #include "qemu/thread.h"
 #include "qemu/main-loop.h"
 #include "qapi/error.h"
 #include "hw/usb.h"
 #include "hw/qdev-properties.h"

 #include <u2f-emu/u2f-emu.h>

 #include "u2f.h"

 /* Counter which sync with a file */
 struct synced_counter {
     /* Emulated device counter */
     struct u2f_emu_vdev_counter vdev_counter;

     /* Private attributes */
     uint32_t value;
     FILE *fp;
 };

 static void counter_increment(struct u2f_emu_vdev_counter *vdev_counter)
 {
     struct synced_counter *counter = (struct synced_counter *)vdev_counter;
     ++counter->value;

     /* Write back */
     if (fseek(counter->fp, 0, SEEK_SET) == -1) {
         return;
     }
     fprintf(counter->fp, "%u\n", counter->value);
 }

 static uint32_t counter_read(struct u2f_emu_vdev_counter *vdev_counter)
 {
     struct synced_counter *counter = (struct synced_counter *)vdev_counter;
     return counter->value;
 }

 typedef struct U2FEmulatedState U2FEmulatedState;

 #define PENDING_OUT_NUM 32

 struct U2FEmulatedState {
     U2FKeyState base;

     /* U2F virtual emulated device */
     u2f_emu_vdev *vdev;
     QemuMutex vdev_mutex;

     /* Properties */
     char *dir;
     char *cert;
     char *privkey;
     char *entropy;
     char *counter;
     struct synced_counter synced_counter;

     /* Pending packets received from the guest */
     uint8_t pending_out[PENDING_OUT_NUM][U2FHID_PACKET_SIZE];
     uint8_t pending_out_start;
     uint8_t pending_out_end;
     uint8_t pending_out_num;
     QemuMutex pending_out_mutex;

     /* Emulation thread and sync */
     QemuCond key_cond;
     QemuMutex key_mutex;
     QemuThread key_thread;
     bool stop_thread;
     EventNotifier notifier;
 };

 #define TYPE_U2F_EMULATED "u2f-emulated"
 #define EMULATED_U2F_KEY(obj) \
     OBJECT_CHECK(U2FEmulatedState, (obj), TYPE_U2F_EMULATED)

 static void u2f_emulated_reset(U2FEmulatedState *key)
 {
     key->pending_out_start = 0;
     key->pending_out_end = 0;
     key->pending_out_num = 0;
 }

 static void u2f_pending_out_add(U2FEmulatedState *key,
                                 const uint8_t packet[U2FHID_PACKET_SIZE])
 {
     int index;

     if (key->pending_out_num >= PENDING_OUT_NUM) {
         return;
     }

     index = key->pending_out_end;
     key->pending_out_end = (index + 1) % PENDING_OUT_NUM;
     ++key->pending_out_num;

     memcpy(&key->pending_out[index], packet, U2FHID_PACKET_SIZE);
 }

 static uint8_t *u2f_pending_out_get(U2FEmulatedState *key)
 {
     int index;

     if (key->pending_out_num == 0) {
         return NULL;
     }

     index  = key->pending_out_start;
     key->pending_out_start = (index + 1) % PENDING_OUT_NUM;
     --key->pending_out_num;

     return key->pending_out[index];
 }

 static void u2f_emulated_recv_from_guest(U2FKeyState *base,
                                     const uint8_t packet[U2FHID_PACKET_SIZE])
 {
     U2FEmulatedState *key = EMULATED_U2F_KEY(base);

     qemu_mutex_lock(&key->pending_out_mutex);
     u2f_pending_out_add(key, packet);
     qemu_mutex_unlock(&key->pending_out_mutex);

     qemu_mutex_lock(&key->key_mutex);
     qemu_cond_signal(&key->key_cond);
     qemu_mutex_unlock(&key->key_mutex);
 }

 static void *u2f_emulated_thread(void* arg)
 {
     U2FEmulatedState *key = arg;
     uint8_t packet[U2FHID_PACKET_SIZE];
     uint8_t *packet_out = NULL;


     while (true) {
         /* Wait signal */
         qemu_mutex_lock(&key->key_mutex);
         qemu_cond_wait(&key->key_cond, &key->key_mutex);
         qemu_mutex_unlock(&key->key_mutex);

         /* Exit thread check */
         if (key->stop_thread) {
             key->stop_thread = false;
             break;
         }

         qemu_mutex_lock(&key->pending_out_mutex);
         packet_out = u2f_pending_out_get(key);
         if (packet_out == NULL) {
             qemu_mutex_unlock(&key->pending_out_mutex);
             continue;
         }
         memcpy(packet, packet_out, U2FHID_PACKET_SIZE);
         qemu_mutex_unlock(&key->pending_out_mutex);

         qemu_mutex_lock(&key->vdev_mutex);
         u2f_emu_vdev_send(key->vdev, U2F_EMU_USB, packet,
                           U2FHID_PACKET_SIZE);

         /* Notify response */
         if (u2f_emu_vdev_has_response(key->vdev, U2F_EMU_USB)) {
             event_notifier_set(&key->notifier);
         }
         qemu_mutex_unlock(&key->vdev_mutex);
     }
     return NULL;
 }

 static ssize_t u2f_emulated_read(const char *path, char *buffer,
                                  size_t buffer_len)
 {
     int fd;
     ssize_t ret;

     fd = qemu_open(path, O_RDONLY);
     if (fd < 0) {
         return -1;
     }

     ret = read(fd, buffer, buffer_len);
     close(fd);

     return ret;
 }

 static bool u2f_emulated_setup_counter(const char *path,
                                        struct synced_counter *counter)
 {
     int fd, ret;
     FILE *fp;

     fd = qemu_open(path, O_RDWR);
     if (fd < 0) {
         return false;
     }
     fp = fdopen(fd, "r+");
     if (fp == NULL) {
         close(fd);
         return false;
     }
     ret = fscanf(fp, "%u", &counter->value);
     if (ret == EOF) {
         fclose(fp);
         return false;
     }
     counter->fp = fp;
     counter->vdev_counter.counter_increment = counter_increment;
     counter->vdev_counter.counter_read = counter_read;

     return true;
 }

 static u2f_emu_rc u2f_emulated_setup_vdev_manualy(U2FEmulatedState *key)
 {
     ssize_t ret;
     char cert_pem[4096], privkey_pem[2048];
     struct u2f_emu_vdev_setup setup_info;

     /* Certificate */
     ret = u2f_emulated_read(key->cert, cert_pem, sizeof(cert_pem));
     if (ret < 0) {
         return -1;
     }

     /* Private key */
     ret = u2f_emulated_read(key->privkey, privkey_pem, sizeof(privkey_pem));
     if (ret < 0) {
         return -1;
     }

     /* Entropy */
     ret = u2f_emulated_read(key->entropy, (char *)&setup_info.entropy,
                             sizeof(setup_info.entropy));
     if (ret < 0) {
         return -1;
     }

     /* Counter */
     if (!u2f_emulated_setup_counter(key->counter, &key->synced_counter)) {
         return -1;
     }

     /* Setup */
     setup_info.certificate = cert_pem;
     setup_info.private_key = privkey_pem;
     setup_info.counter = (struct u2f_emu_vdev_counter *)&key->synced_counter;

     return u2f_emu_vdev_new(&key->vdev, &setup_info);
 }

 static void u2f_emulated_event_handler(EventNotifier *notifier)
 {
     U2FEmulatedState *key = container_of(notifier, U2FEmulatedState, notifier);
     size_t packet_size;
     uint8_t *packet_in = NULL;

     event_notifier_test_and_clear(&key->notifier);
     qemu_mutex_lock(&key->vdev_mutex);
     while (u2f_emu_vdev_has_response(key->vdev, U2F_EMU_USB)) {
         packet_size = u2f_emu_vdev_get_response(key->vdev, U2F_EMU_USB,
                                                 &packet_in);
         if (packet_size == U2FHID_PACKET_SIZE) {
             u2f_send_to_guest(&key->base, packet_in);
         }
         u2f_emu_vdev_free_response(packet_in);
     }
     qemu_mutex_unlock(&key->vdev_mutex);
 }

 static void u2f_emulated_realize(U2FKeyState *base, Error **errp)
 {
     U2FEmulatedState *key = EMULATED_U2F_KEY(base);
     u2f_emu_rc rc;

     if (key->cert != NULL || key->privkey != NULL || key->entropy != NULL
         || key->counter != NULL) {
         if (key->cert != NULL && key->privkey != NULL
             && key->entropy != NULL && key->counter != NULL) {
             rc = u2f_emulated_setup_vdev_manualy(key);
         } else {
             error_setg(errp, "%s: cert, priv, entropy and counter "
                        "parameters must be provided to manualy configure "
                        "the emulated device", TYPE_U2F_EMULATED);
             return;
         }
     } else if (key->dir != NULL) {
         rc = u2f_emu_vdev_new_from_dir(&key->vdev, key->dir);
     } else {
         rc = u2f_emu_vdev_new_ephemeral(&key->vdev);
     }

     if (rc != U2F_EMU_OK) {
         error_setg(errp, "%s: Failed to setup the key", TYPE_U2F_EMULATED);
         return;
     }

     if (event_notifier_init(&key->notifier, false) < 0) {
         error_setg(errp, "%s: Failed to initialize notifier",
                    TYPE_U2F_EMULATED);
         return;
     }
     /* Notifier */
     event_notifier_set_handler(&key->notifier, u2f_emulated_event_handler);

     /* Synchronization */
     qemu_cond_init(&key->key_cond);
     qemu_mutex_init(&key->vdev_mutex);
     qemu_mutex_init(&key->pending_out_mutex);
     qemu_mutex_init(&key->key_mutex);
     u2f_emulated_reset(key);

     /* Thread */
     key->stop_thread = false;
     qemu_thread_create(&key->key_thread, "u2f-key", u2f_emulated_thread,
                        key, QEMU_THREAD_JOINABLE);
 }

 static void u2f_emulated_unrealize(U2FKeyState *base)
 {
     U2FEmulatedState *key = EMULATED_U2F_KEY(base);

     /* Thread */
     key->stop_thread = true;
     qemu_cond_signal(&key->key_cond);
     qemu_thread_join(&key->key_thread);

     /* Notifier */
     event_notifier_set_handler(&key->notifier, NULL);
     event_notifier_cleanup(&key->notifier);

     /* Synchronization */
     qemu_cond_destroy(&key->key_cond);
     qemu_mutex_destroy(&key->vdev_mutex);
     qemu_mutex_destroy(&key->key_mutex);
     qemu_mutex_destroy(&key->pending_out_mutex);

     /* Vdev */
     u2f_emu_vdev_free(key->vdev);
     if (key->synced_counter.fp != NULL) {
         fclose(key->synced_counter.fp);
     }
 }

 static Property u2f_emulated_properties[] = {
     DEFINE_PROP_STRING("dir", U2FEmulatedState, dir),
     DEFINE_PROP_STRING("cert", U2FEmulatedState, cert),
     DEFINE_PROP_STRING("privkey", U2FEmulatedState, privkey),
     DEFINE_PROP_STRING("entropy", U2FEmulatedState, entropy),
     DEFINE_PROP_STRING("counter", U2FEmulatedState, counter),
     DEFINE_PROP_END_OF_LIST(),
 };

 static void u2f_emulated_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
     U2FKeyClass *kc = U2F_KEY_CLASS(klass);

     kc->realize = u2f_emulated_realize;
     kc->unrealize = u2f_emulated_unrealize;
     kc->recv_from_guest = u2f_emulated_recv_from_guest;
     dc->desc = "QEMU U2F emulated key";
     device_class_set_props(dc, u2f_emulated_properties);
 }

 static const TypeInfo u2f_key_emulated_info = {
     .name = TYPE_U2F_EMULATED,
     .parent = TYPE_U2F_KEY,
     .instance_size = sizeof(U2FEmulatedState),
     .class_init = u2f_emulated_class_init
 };

 static void u2f_key_emulated_register_types(void)
 {
     type_register_static(&u2f_key_emulated_info);
 }

 type_init(u2f_key_emulated_register_types)
	/*
	* U2F USB Emulated device.
	*
	* Copyright (c) 2020 César Belley <cesar.belley@lse.epita.fr>
	* Written by César Belley <cesar.belley@lse.epita.fr>
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*/

	#include "qemu/osdep.h"
	#include "qemu/module.h"
	#include "qemu/thread.h"
	#include "qemu/main-loop.h"
	#include "qapi/error.h"
	#include "hw/usb.h"
	#include "hw/qdev-properties.h"

	#include <u2f-emu/u2f-emu.h>

	#include "u2f.h"

	/* Counter which sync with a file */
	struct synced_counter {
	/* Emulated device counter */
	struct u2f_emu_vdev_counter vdev_counter;

	/* Private attributes */
	uint32_t value;
	FILE *fp;
	};

	static void counter_increment(struct u2f_emu_vdev_counter *vdev_counter)
	{
	struct synced_counter counter = (struct synced_counter )vdev_counter;
	++counter->value;

	/* Write back */
	if (fseek(counter->fp, 0, SEEK_SET) == -1) {
	return;
	}
	fprintf(counter->fp, "%u\n", counter->value);
	}

	static uint32_t counter_read(struct u2f_emu_vdev_counter *vdev_counter)
	{
	struct synced_counter counter = (struct synced_counter )vdev_counter;
	return counter->value;
	}

	typedef struct U2FEmulatedState U2FEmulatedState;

	#define PENDING_OUT_NUM 32

	struct U2FEmulatedState {
	U2FKeyState base;

	/* U2F virtual emulated device */
	u2f_emu_vdev *vdev;
	QemuMutex vdev_mutex;

	/* Properties */
	char *dir;
	char *cert;
	char *privkey;
	char *entropy;
	char *counter;
	struct synced_counter synced_counter;

	/* Pending packets received from the guest */
	uint8_t pending_out[PENDING_OUT_NUM][U2FHID_PACKET_SIZE];
	uint8_t pending_out_start;
	uint8_t pending_out_end;
	uint8_t pending_out_num;
	QemuMutex pending_out_mutex;

	/* Emulation thread and sync */
	QemuCond key_cond;
	QemuMutex key_mutex;
	QemuThread key_thread;
	bool stop_thread;
	EventNotifier notifier;
	};

	#define TYPE_U2F_EMULATED "u2f-emulated"
	#define EMULATED_U2F_KEY(obj) \
	OBJECT_CHECK(U2FEmulatedState, (obj), TYPE_U2F_EMULATED)

	static void u2f_emulated_reset(U2FEmulatedState *key)
	{
	key->pending_out_start = 0;
	key->pending_out_end = 0;
	key->pending_out_num = 0;
	}

	static void u2f_pending_out_add(U2FEmulatedState *key,
	const uint8_t packet[U2FHID_PACKET_SIZE])
	{
	int index;

	if (key->pending_out_num >= PENDING_OUT_NUM) {
	return;
	}

	index = key->pending_out_end;
	key->pending_out_end = (index + 1) % PENDING_OUT_NUM;
	++key->pending_out_num;

	memcpy(&key->pending_out[index], packet, U2FHID_PACKET_SIZE);
	}

	static uint8_t u2f_pending_out_get(U2FEmulatedState key)
	{
	int index;

	if (key->pending_out_num == 0) {
	return NULL;
	}

	index = key->pending_out_start;
	key->pending_out_start = (index + 1) % PENDING_OUT_NUM;
	--key->pending_out_num;

	return key->pending_out[index];
	}

	static void u2f_emulated_recv_from_guest(U2FKeyState *base,
	const uint8_t packet[U2FHID_PACKET_SIZE])
	{
	U2FEmulatedState *key = EMULATED_U2F_KEY(base);

	qemu_mutex_lock(&key->pending_out_mutex);
	u2f_pending_out_add(key, packet);
	qemu_mutex_unlock(&key->pending_out_mutex);

	qemu_mutex_lock(&key->key_mutex);
	qemu_cond_signal(&key->key_cond);
	qemu_mutex_unlock(&key->key_mutex);
	}

	static void u2f_emulated_thread(void arg)
	{
	U2FEmulatedState *key = arg;
	uint8_t packet[U2FHID_PACKET_SIZE];
	uint8_t *packet_out = NULL;


	while (true) {
	/* Wait signal */
	qemu_mutex_lock(&key->key_mutex);
	qemu_cond_wait(&key->key_cond, &key->key_mutex);
	qemu_mutex_unlock(&key->key_mutex);

	/* Exit thread check */
	if (key->stop_thread) {
	key->stop_thread = false;
	break;
	}

	qemu_mutex_lock(&key->pending_out_mutex);
	packet_out = u2f_pending_out_get(key);
	if (packet_out == NULL) {
	qemu_mutex_unlock(&key->pending_out_mutex);
	continue;
	}
	memcpy(packet, packet_out, U2FHID_PACKET_SIZE);
	qemu_mutex_unlock(&key->pending_out_mutex);

	qemu_mutex_lock(&key->vdev_mutex);
	u2f_emu_vdev_send(key->vdev, U2F_EMU_USB, packet,
	U2FHID_PACKET_SIZE);

	/* Notify response */
	if (u2f_emu_vdev_has_response(key->vdev, U2F_EMU_USB)) {
	event_notifier_set(&key->notifier);
	}
	qemu_mutex_unlock(&key->vdev_mutex);
	}
	return NULL;
	}

	static ssize_t u2f_emulated_read(const char path, char buffer,
	size_t buffer_len)
	{
	int fd;
	ssize_t ret;

	fd = qemu_open(path, O_RDONLY);
	if (fd < 0) {
	return -1;
	}

	ret = read(fd, buffer, buffer_len);
	close(fd);

	return ret;
	}

	static bool u2f_emulated_setup_counter(const char *path,
	struct synced_counter *counter)
	{
	int fd, ret;
	FILE *fp;

	fd = qemu_open(path, O_RDWR);
	if (fd < 0) {
	return false;
	}
	fp = fdopen(fd, "r+");
	if (fp == NULL) {
	close(fd);
	return false;
	}
	ret = fscanf(fp, "%u", &counter->value);
	if (ret == EOF) {
	fclose(fp);
	return false;
	}
	counter->fp = fp;
	counter->vdev_counter.counter_increment = counter_increment;
	counter->vdev_counter.counter_read = counter_read;

	return true;
	}

	static u2f_emu_rc u2f_emulated_setup_vdev_manualy(U2FEmulatedState *key)
	{
	ssize_t ret;
	char cert_pem[4096], privkey_pem[2048];
	struct u2f_emu_vdev_setup setup_info;

	/* Certificate */
	ret = u2f_emulated_read(key->cert, cert_pem, sizeof(cert_pem));
	if (ret < 0) {
	return -1;
	}

	/* Private key */
	ret = u2f_emulated_read(key->privkey, privkey_pem, sizeof(privkey_pem));
	if (ret < 0) {
	return -1;
	}

	/* Entropy */
	ret = u2f_emulated_read(key->entropy, (char *)&setup_info.entropy,
	sizeof(setup_info.entropy));
	if (ret < 0) {
	return -1;
	}

	/* Counter */
	if (!u2f_emulated_setup_counter(key->counter, &key->synced_counter)) {
	return -1;
	}

	/* Setup */
	setup_info.certificate = cert_pem;
	setup_info.private_key = privkey_pem;
	setup_info.counter = (struct u2f_emu_vdev_counter *)&key->synced_counter;

	return u2f_emu_vdev_new(&key->vdev, &setup_info);
	}

	static void u2f_emulated_event_handler(EventNotifier *notifier)
	{
	U2FEmulatedState *key = container_of(notifier, U2FEmulatedState, notifier);
	size_t packet_size;
	uint8_t *packet_in = NULL;

	event_notifier_test_and_clear(&key->notifier);
	qemu_mutex_lock(&key->vdev_mutex);
	while (u2f_emu_vdev_has_response(key->vdev, U2F_EMU_USB)) {
	packet_size = u2f_emu_vdev_get_response(key->vdev, U2F_EMU_USB,
	&packet_in);
	if (packet_size == U2FHID_PACKET_SIZE) {
	u2f_send_to_guest(&key->base, packet_in);
	}
	u2f_emu_vdev_free_response(packet_in);
	}
	qemu_mutex_unlock(&key->vdev_mutex);
	}

	static void u2f_emulated_realize(U2FKeyState base, Error *errp)
	{
	U2FEmulatedState *key = EMULATED_U2F_KEY(base);
	u2f_emu_rc rc;

	if (key->cert != NULL \|\| key->privkey != NULL \|\| key->entropy != NULL
	\|\| key->counter != NULL) {
	if (key->cert != NULL && key->privkey != NULL
	&& key->entropy != NULL && key->counter != NULL) {
	rc = u2f_emulated_setup_vdev_manualy(key);
	} else {
	error_setg(errp, "%s: cert, priv, entropy and counter "
	"parameters must be provided to manualy configure "
	"the emulated device", TYPE_U2F_EMULATED);
	return;
	}
	} else if (key->dir != NULL) {
	rc = u2f_emu_vdev_new_from_dir(&key->vdev, key->dir);
	} else {
	rc = u2f_emu_vdev_new_ephemeral(&key->vdev);
	}

	if (rc != U2F_EMU_OK) {
	error_setg(errp, "%s: Failed to setup the key", TYPE_U2F_EMULATED);
	return;
	}

	if (event_notifier_init(&key->notifier, false) < 0) {
	error_setg(errp, "%s: Failed to initialize notifier",
	TYPE_U2F_EMULATED);
	return;
	}
	/* Notifier */
	event_notifier_set_handler(&key->notifier, u2f_emulated_event_handler);

	/* Synchronization */
	qemu_cond_init(&key->key_cond);
	qemu_mutex_init(&key->vdev_mutex);
	qemu_mutex_init(&key->pending_out_mutex);
	qemu_mutex_init(&key->key_mutex);
	u2f_emulated_reset(key);

	/* Thread */
	key->stop_thread = false;
	qemu_thread_create(&key->key_thread, "u2f-key", u2f_emulated_thread,
	key, QEMU_THREAD_JOINABLE);
	}

	static void u2f_emulated_unrealize(U2FKeyState *base)
	{
	U2FEmulatedState *key = EMULATED_U2F_KEY(base);

	/* Thread */
	key->stop_thread = true;
	qemu_cond_signal(&key->key_cond);
	qemu_thread_join(&key->key_thread);

	/* Notifier */
	event_notifier_set_handler(&key->notifier, NULL);
	event_notifier_cleanup(&key->notifier);

	/* Synchronization */
	qemu_cond_destroy(&key->key_cond);
	qemu_mutex_destroy(&key->vdev_mutex);
	qemu_mutex_destroy(&key->key_mutex);
	qemu_mutex_destroy(&key->pending_out_mutex);

	/* Vdev */
	u2f_emu_vdev_free(key->vdev);
	if (key->synced_counter.fp != NULL) {
	fclose(key->synced_counter.fp);
	}
	}

	static Property u2f_emulated_properties[] = {
	DEFINE_PROP_STRING("dir", U2FEmulatedState, dir),
	DEFINE_PROP_STRING("cert", U2FEmulatedState, cert),
	DEFINE_PROP_STRING("privkey", U2FEmulatedState, privkey),
	DEFINE_PROP_STRING("entropy", U2FEmulatedState, entropy),
	DEFINE_PROP_STRING("counter", U2FEmulatedState, counter),
	DEFINE_PROP_END_OF_LIST(),
	};

	static void u2f_emulated_class_init(ObjectClass klass, void data)
	{
	DeviceClass *dc = DEVICE_CLASS(klass);
	U2FKeyClass *kc = U2F_KEY_CLASS(klass);

	kc->realize = u2f_emulated_realize;
	kc->unrealize = u2f_emulated_unrealize;
	kc->recv_from_guest = u2f_emulated_recv_from_guest;
	dc->desc = "QEMU U2F emulated key";
	device_class_set_props(dc, u2f_emulated_properties);
	}

	static const TypeInfo u2f_key_emulated_info = {
	.name = TYPE_U2F_EMULATED,
	.parent = TYPE_U2F_KEY,
	.instance_size = sizeof(U2FEmulatedState),
	.class_init = u2f_emulated_class_init
	};

	static void u2f_key_emulated_register_types(void)
	{
	type_register_static(&u2f_key_emulated_info);
	}

	type_init(u2f_key_emulated_register_types)