diff options
Diffstat (limited to 'hw/usb/u2f-emulated.c')
| -rw-r--r-- | hw/usb/u2f-emulated.c | 405 |
1 files changed, 405 insertions, 0 deletions
diff --git a/hw/usb/u2f-emulated.c b/hw/usb/u2f-emulated.c new file mode 100644 index 000000000..63cceaa5f --- /dev/null +++ b/hw/usb/u2f-emulated.c @@ -0,0 +1,405 @@ +/* + * 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_old(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_old(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 manually 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) |