unleashed-firmware/applications/u2f/u2f_hid.c

#include <furi.h>
#include "u2f_hid.h"
#include "u2f.h"
#include <furi_hal.h>
#include <gui/gui.h>
#include <input/input.h>
#include <lib/toolbox/args.h>
#include <furi_hal_usb_hid_u2f.h>
#include <storage/storage.h>

#include <furi_hal_console.h>

#define TAG "U2FHID"
#define WORKER_TAG TAG "Worker"

#define U2F_HID_MAX_PAYLOAD_LEN ((HID_U2F_PACKET_LEN - 7) + 128 * (HID_U2F_PACKET_LEN - 5))

#define U2F_HID_TYPE_MASK 0x80 // Frame type mask
#define U2F_HID_TYPE_INIT 0x80 // Initial frame identifier
#define U2F_HID_TYPE_CONT 0x00 // Continuation frame identifier

#define U2F_HID_PING (U2F_HID_TYPE_INIT | 0x01) // Echo data through local processor only
#define U2F_HID_MSG (U2F_HID_TYPE_INIT | 0x03) // Send U2F message frame
#define U2F_HID_LOCK (U2F_HID_TYPE_INIT | 0x04) // Send lock channel command
#define U2F_HID_INIT (U2F_HID_TYPE_INIT | 0x06) // Channel initialization
#define U2F_HID_WINK (U2F_HID_TYPE_INIT | 0x08) // Send device identification wink
#define U2F_HID_ERROR (U2F_HID_TYPE_INIT | 0x3f) // Error response

#define U2F_HID_ERR_NONE 0x00 // No error
#define U2F_HID_ERR_INVALID_CMD 0x01 // Invalid command
#define U2F_HID_ERR_INVALID_PAR 0x02 // Invalid parameter
#define U2F_HID_ERR_INVALID_LEN 0x03 // Invalid message length
#define U2F_HID_ERR_INVALID_SEQ 0x04 // Invalid message sequencing
#define U2F_HID_ERR_MSG_TIMEOUT 0x05 // Message has timed out
#define U2F_HID_ERR_CHANNEL_BUSY 0x06 // Channel busy
#define U2F_HID_ERR_LOCK_REQUIRED 0x0a // Command requires channel lock
#define U2F_HID_ERR_SYNC_FAIL 0x0b // SYNC command failed
#define U2F_HID_ERR_OTHER 0x7f // Other unspecified error

#define U2F_HID_BROADCAST_CID 0xFFFFFFFF

typedef enum {
    WorkerEvtReserved = (1 << 0),
    WorkerEvtStop = (1 << 1),
    WorkerEvtConnect = (1 << 2),
    WorkerEvtDisconnect = (1 << 3),
    WorkerEvtRequest = (1 << 4),
    WorkerEvtUnlock = (1 << 5),
} WorkerEvtFlags;

struct U2fHid_packet {
    uint32_t cid;
    uint16_t len;
    uint8_t cmd;
    uint8_t payload[U2F_HID_MAX_PAYLOAD_LEN];
};

struct U2fHid {
    FuriThread* thread;
    FuriTimer* lock_timer;
    struct U2fHid_packet packet;
    uint8_t seq_id_last;
    uint16_t req_buf_ptr;
    uint32_t req_len_left;
    uint32_t lock_cid;
    bool lock;
    U2fData* u2f_instance;
};

static void u2f_hid_event_callback(HidU2fEvent ev, void* context) {
    furi_assert(context);
    U2fHid* u2f_hid = context;

    if(ev == HidU2fDisconnected)
        furi_thread_flags_set(furi_thread_get_id(u2f_hid->thread), WorkerEvtDisconnect);
    else if(ev == HidU2fConnected)
        furi_thread_flags_set(furi_thread_get_id(u2f_hid->thread), WorkerEvtConnect);
    else if(ev == HidU2fRequest)
        furi_thread_flags_set(furi_thread_get_id(u2f_hid->thread), WorkerEvtRequest);
}

static void u2f_hid_lock_timeout_callback(void* context) {
    furi_assert(context);
    U2fHid* u2f_hid = context;

    furi_thread_flags_set(furi_thread_get_id(u2f_hid->thread), WorkerEvtUnlock);
}

static void u2f_hid_send_response(U2fHid* u2f_hid) {
    uint8_t packet_buf[HID_U2F_PACKET_LEN];
    uint16_t len_remain = u2f_hid->packet.len;
    uint8_t len_cur = 0;
    uint8_t seq_cnt = 0;
    uint16_t data_ptr = 0;

    memset(packet_buf, 0, HID_U2F_PACKET_LEN);
    memcpy(packet_buf, &(u2f_hid->packet.cid), 4);

    // Init packet
    packet_buf[4] = u2f_hid->packet.cmd;
    packet_buf[5] = u2f_hid->packet.len >> 8;
    packet_buf[6] = (u2f_hid->packet.len & 0xFF);
    len_cur = (len_remain < (HID_U2F_PACKET_LEN - 7)) ? (len_remain) : (HID_U2F_PACKET_LEN - 7);
    if(len_cur > 0) memcpy(&packet_buf[7], u2f_hid->packet.payload, len_cur);
    furi_hal_hid_u2f_send_response(packet_buf, HID_U2F_PACKET_LEN);
    data_ptr = len_cur;
    len_remain -= len_cur;

    // Continuation packets
    while(len_remain > 0) {
        memset(&packet_buf[4], 0, HID_U2F_PACKET_LEN - 4);
        packet_buf[4] = seq_cnt;
        len_cur = (len_remain < (HID_U2F_PACKET_LEN - 5)) ? (len_remain) :
                                                            (HID_U2F_PACKET_LEN - 5);
        memcpy(&packet_buf[5], &(u2f_hid->packet.payload[data_ptr]), len_cur);
        furi_hal_hid_u2f_send_response(packet_buf, HID_U2F_PACKET_LEN);
        seq_cnt++;
        len_remain -= len_cur;
        data_ptr += len_cur;
    }
}

static void u2f_hid_send_error(U2fHid* u2f_hid, uint8_t error) {
    u2f_hid->packet.len = 1;
    u2f_hid->packet.cmd = U2F_HID_ERROR;
    u2f_hid->packet.payload[0] = error;
    u2f_hid_send_response(u2f_hid);
}

static bool u2f_hid_parse_request(U2fHid* u2f_hid) {
    FURI_LOG_D(
        WORKER_TAG,
        "Req cid=%lX cmd=%x len=%u",
        u2f_hid->packet.cid,
        u2f_hid->packet.cmd,
        u2f_hid->packet.len);

    if(u2f_hid->packet.cmd == U2F_HID_PING) { // PING - echo request back
        u2f_hid_send_response(u2f_hid);

    } else if(u2f_hid->packet.cmd == U2F_HID_MSG) { // MSG - U2F message
        if((u2f_hid->lock == true) && (u2f_hid->packet.cid != u2f_hid->lock_cid)) return false;
        uint16_t resp_len =
            u2f_msg_parse(u2f_hid->u2f_instance, u2f_hid->packet.payload, u2f_hid->packet.len);
        if(resp_len > 0) {
            u2f_hid->packet.len = resp_len;
            u2f_hid_send_response(u2f_hid);
        } else
            return false;

    } else if(u2f_hid->packet.cmd == U2F_HID_LOCK) { // LOCK - lock all channels except current
        if(u2f_hid->packet.len != 1) return false;
        uint8_t lock_timeout = u2f_hid->packet.payload[0];
        if(lock_timeout == 0) { // Lock off
            u2f_hid->lock = false;
            u2f_hid->lock_cid = 0;
        } else { // Lock on
            u2f_hid->lock = true;
            u2f_hid->lock_cid = u2f_hid->packet.cid;
            furi_timer_start(u2f_hid->lock_timer, lock_timeout * 1000);
        }

    } else if(u2f_hid->packet.cmd == U2F_HID_INIT) { // INIT - channel initialization request
        if((u2f_hid->packet.len != 8) || (u2f_hid->packet.cid != U2F_HID_BROADCAST_CID) ||
           (u2f_hid->lock == true))
            return false;
        u2f_hid->packet.len = 17;
        uint32_t random_cid = furi_hal_random_get();
        memcpy(&(u2f_hid->packet.payload[8]), &random_cid, 4);
        u2f_hid->packet.payload[12] = 2; // Protocol version
        u2f_hid->packet.payload[13] = 1; // Device version major
        u2f_hid->packet.payload[14] = 0; // Device version minor
        u2f_hid->packet.payload[15] = 1; // Device build version
        u2f_hid->packet.payload[16] = 1; // Capabilities: wink
        u2f_hid_send_response(u2f_hid);

    } else if(u2f_hid->packet.cmd == U2F_HID_WINK) { // WINK - notify user
        if(u2f_hid->packet.len != 0) return false;
        u2f_wink(u2f_hid->u2f_instance);
        u2f_hid->packet.len = 0;
        u2f_hid_send_response(u2f_hid);
    } else
        return false;
    return true;
}

static int32_t u2f_hid_worker(void* context) {
    U2fHid* u2f_hid = context;
    uint8_t packet_buf[HID_U2F_PACKET_LEN];

    FURI_LOG_D(WORKER_TAG, "Init");

    FuriHalUsbInterface* usb_mode_prev = furi_hal_usb_get_config();
    furi_check(furi_hal_usb_set_config(&usb_hid_u2f, NULL) == true);

    u2f_hid->lock_timer =
        furi_timer_alloc(u2f_hid_lock_timeout_callback, FuriTimerTypeOnce, u2f_hid);

    furi_hal_hid_u2f_set_callback(u2f_hid_event_callback, u2f_hid);

    while(1) {
        uint32_t flags = furi_thread_flags_wait(
            WorkerEvtStop | WorkerEvtConnect | WorkerEvtDisconnect | WorkerEvtRequest,
            FuriFlagWaitAny,
            FuriWaitForever);
        furi_check((flags & FuriFlagError) == 0);
        if(flags & WorkerEvtStop) break;
        if(flags & WorkerEvtConnect) {
            u2f_set_state(u2f_hid->u2f_instance, 1);
            FURI_LOG_D(WORKER_TAG, "Connect");
        }
        if(flags & WorkerEvtDisconnect) {
            u2f_set_state(u2f_hid->u2f_instance, 0);
            FURI_LOG_D(WORKER_TAG, "Disconnect");
        }
        if(flags & WorkerEvtRequest) {
            uint32_t len_cur = furi_hal_hid_u2f_get_request(packet_buf);
            if(len_cur > 0) {
                if((packet_buf[4] & U2F_HID_TYPE_MASK) == U2F_HID_TYPE_INIT) {
                    // Init packet
                    u2f_hid->packet.len = (packet_buf[5] << 8) | (packet_buf[6]);
                    if(u2f_hid->packet.len > (len_cur - 7)) {
                        u2f_hid->req_len_left = u2f_hid->packet.len - (len_cur - 7);
                        len_cur = len_cur - 7;
                    } else {
                        u2f_hid->req_len_left = 0;
                        len_cur = u2f_hid->packet.len;
                    }
                    memcpy(&(u2f_hid->packet.cid), packet_buf, 4);
                    u2f_hid->packet.cmd = packet_buf[4];
                    u2f_hid->seq_id_last = 0;
                    u2f_hid->req_buf_ptr = len_cur;
                    if(len_cur > 0) memcpy(u2f_hid->packet.payload, &packet_buf[7], len_cur);
                } else {
                    // Continuation packet
                    if(u2f_hid->req_len_left > 0) {
                        uint32_t cid_temp = 0;
                        memcpy(&cid_temp, packet_buf, 4);
                        uint8_t seq_temp = packet_buf[4];
                        if((cid_temp == u2f_hid->packet.cid) &&
                           (seq_temp == u2f_hid->seq_id_last)) {
                            if(u2f_hid->req_len_left > (len_cur - 5)) {
                                len_cur = len_cur - 5;
                                u2f_hid->req_len_left -= len_cur;
                            } else {
                                len_cur = u2f_hid->req_len_left;
                                u2f_hid->req_len_left = 0;
                            }
                            memcpy(
                                &(u2f_hid->packet.payload[u2f_hid->req_buf_ptr]),
                                &packet_buf[5],
                                len_cur);
                            u2f_hid->req_buf_ptr += len_cur;
                            u2f_hid->seq_id_last++;
                        }
                    }
                }
                if(u2f_hid->req_len_left == 0) {
                    if(u2f_hid_parse_request(u2f_hid) == false) {
                        u2f_hid_send_error(u2f_hid, U2F_HID_ERR_INVALID_CMD);
                    }
                }
            }
        }
        if(flags & WorkerEvtUnlock) {
            u2f_hid->lock = false;
            u2f_hid->lock_cid = 0;
        }
    }
    furi_timer_stop(u2f_hid->lock_timer);
    furi_timer_free(u2f_hid->lock_timer);

    furi_hal_hid_u2f_set_callback(NULL, NULL);
    furi_hal_usb_set_config(usb_mode_prev, NULL);
    FURI_LOG_D(WORKER_TAG, "End");

    return 0;
}

U2fHid* u2f_hid_start(U2fData* u2f_inst) {
    U2fHid* u2f_hid = malloc(sizeof(U2fHid));

    u2f_hid->u2f_instance = u2f_inst;

    u2f_hid->thread = furi_thread_alloc();
    furi_thread_set_name(u2f_hid->thread, "U2fHidWorker");
    furi_thread_set_stack_size(u2f_hid->thread, 2048);
    furi_thread_set_context(u2f_hid->thread, u2f_hid);
    furi_thread_set_callback(u2f_hid->thread, u2f_hid_worker);
    furi_thread_start(u2f_hid->thread);
    return u2f_hid;
}

void u2f_hid_stop(U2fHid* u2f_hid) {
    furi_assert(u2f_hid);
    furi_thread_flags_set(furi_thread_get_id(u2f_hid->thread), WorkerEvtStop);
    furi_thread_join(u2f_hid->thread);
    furi_thread_free(u2f_hid->thread);
    free(u2f_hid);
}