/*

 * Copyright (c) 2018-2022 Yubico AB. All rights reserved.

 * Use of this source code is governed by a BSD-style

 * license that can be found in the LICENSE file.

 * SPDX-License-Identifier: BSD-2-Clause

 */

#include <openssl/sha.h>

#include <openssl/x509.h>

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

#include <errno.h>

#include "fido.h"

#include "fido/es256.h"

#include "fallthrough.h"

#define U2F_PACE_MS (100)

#if defined(_MSC_VER)

static int

usleep(unsigned int usec)

{

        Sleep(usec / 1000);

        return (0);

}

#endif

static int

delay_ms(unsigned int ms, int *ms_remain)

{

        if (*ms_remain > -1 && (unsigned int)*ms_remain < ms)

                ms = (unsigned int)*ms_remain;

        if (ms > UINT_MAX / 1000) {

                fido_log_debug("%s: ms=%u", __func__, ms);

                return (-1);

        }

        if (usleep(ms * 1000) < 0) {

                fido_log_error(errno, "%s: usleep", __func__);

                return (-1);

        }

        if (*ms_remain > -1)

                *ms_remain -= (int)ms;

        return (0);

}

static int

sig_get(fido_blob_t *sig, const unsigned char **buf, size_t *len)

{

        sig->len = *len; /* consume the whole buffer */

        if ((sig->ptr = calloc(1, sig->len)) == NULL ||

            fido_buf_read(buf, len, sig->ptr, sig->len) < 0) {

                fido_log_debug("%s: fido_buf_read", __func__);

                fido_blob_reset(sig);

                return (-1);

        }

        return (0);

}

static int

x5c_get(fido_blob_t *x5c, const unsigned char **buf, size_t *len)

{

        X509    *cert = NULL;

        int      ok = -1;

        if (*len > LONG_MAX) {

                fido_log_debug("%s: invalid len %zu", __func__, *len);

                goto fail;

        }

        /* find out the certificate's length */

        const unsigned char *end = *buf;

        if ((cert = d2i_X509(NULL, &end, (long)*len)) == NULL || end <= *buf ||

            (x5c->len = (size_t)(end - *buf)) >= *len) {

                fido_log_debug("%s: d2i_X509", __func__);

                goto fail;

        }

        /* read accordingly */

        if ((x5c->ptr = calloc(1, x5c->len)) == NULL ||

            fido_buf_read(buf, len, x5c->ptr, x5c->len) < 0) {

                fido_log_debug("%s: fido_buf_read", __func__);

                goto fail;

        }

        ok = 0;

fail:

        if (cert != NULL)

                X509_free(cert);

        if (ok < 0)

                fido_blob_reset(x5c);

        return (ok);

}

static int

authdata_fake(const char *rp_id, uint8_t flags, uint32_t sigcount,

    fido_blob_t *fake_cbor_ad)

{

        fido_authdata_t  ad;

        cbor_item_t     *item = NULL;

        size_t           alloc_len;

        memset(&ad, 0, sizeof(ad));

        if (SHA256((const void *)rp_id, strlen(rp_id),

            ad.rp_id_hash) != ad.rp_id_hash) {

                fido_log_debug("%s: sha256", __func__);

                return (-1);

        }

        ad.flags = flags; /* XXX translate? */

        ad.sigcount = sigcount;

        if ((item = cbor_build_bytestring((const unsigned char *)&ad,

            sizeof(ad))) == NULL) {

                fido_log_debug("%s: cbor_build_bytestring", __func__);

                return (-1);

        }

        if (fake_cbor_ad->ptr != NULL ||

            (fake_cbor_ad->len = cbor_serialize_alloc(item, &fake_cbor_ad->ptr,

            &alloc_len)) == 0) {

                fido_log_debug("%s: cbor_serialize_alloc", __func__);

                cbor_decref(&item);

                return (-1);

        }

        cbor_decref(&item);

        return (0);

}

/* TODO: use u2f_get_touch_begin & u2f_get_touch_status instead */

static int

send_dummy_register(fido_dev_t *dev, int *ms)

{

        iso7816_apdu_t  *apdu = NULL;

        unsigned char   *reply = NULL;

        unsigned char    challenge[SHA256_DIGEST_LENGTH];

        unsigned char    application[SHA256_DIGEST_LENGTH];

        int              r;

        /* dummy challenge & application */

        memset(&challenge, 0xff, sizeof(challenge));

        memset(&application, 0xff, sizeof(application));

        if ((apdu = iso7816_new(0, U2F_CMD_REGISTER, 0, 2 *

            SHA256_DIGEST_LENGTH)) == NULL ||

            iso7816_add(apdu, &challenge, sizeof(challenge)) < 0 ||

            iso7816_add(apdu, &application, sizeof(application)) < 0) {

                fido_log_debug("%s: iso7816", __func__);

                r = FIDO_ERR_INTERNAL;

                goto fail;

        }

        if ((reply = malloc(FIDO_MAXMSG)) == NULL) {

                fido_log_debug("%s: malloc", __func__);

                r = FIDO_ERR_INTERNAL;

                goto fail;

        }

        do {

                if (fido_tx(dev, CTAP_CMD_MSG, iso7816_ptr(apdu),

                    iso7816_len(apdu), ms) < 0) {

                        fido_log_debug("%s: fido_tx", __func__);

                        r = FIDO_ERR_TX;

                        goto fail;

                }

                if (fido_rx(dev, CTAP_CMD_MSG, reply, FIDO_MAXMSG, ms) < 2) {

                        fido_log_debug("%s: fido_rx", __func__);

                        r = FIDO_ERR_RX;

                        goto fail;

                }

                if (delay_ms(U2F_PACE_MS, ms) != 0) {

                        fido_log_debug("%s: delay_ms", __func__);

                        r = FIDO_ERR_RX;

                        goto fail;

                }

        } while (((reply[0] << 8) | reply[1]) == SW_CONDITIONS_NOT_SATISFIED);

        r = FIDO_OK;

fail:

        iso7816_free(&apdu);

        freezero(reply, FIDO_MAXMSG);

        return (r);

}

static int

key_lookup(fido_dev_t *dev, const char *rp_id, const fido_blob_t *key_id,

    int *found, int *ms)

{

        iso7816_apdu_t  *apdu = NULL;

        unsigned char   *reply = NULL;

        unsigned char    challenge[SHA256_DIGEST_LENGTH];

        unsigned char    rp_id_hash[SHA256_DIGEST_LENGTH];

        uint8_t          key_id_len;

        int              r;

        if (key_id->len > UINT8_MAX || rp_id == NULL) {

                fido_log_debug("%s: key_id->len=%zu, rp_id=%p", __func__,

                    key_id->len, (const void *)rp_id);

                r = FIDO_ERR_INVALID_ARGUMENT;

                goto fail;

        }

        memset(&challenge, 0xff, sizeof(challenge));

        memset(&rp_id_hash, 0, sizeof(rp_id_hash));

        if (SHA256((const void *)rp_id, strlen(rp_id),

            rp_id_hash) != rp_id_hash) {

                fido_log_debug("%s: sha256", __func__);

                r = FIDO_ERR_INTERNAL;

                goto fail;

        }

        key_id_len = (uint8_t)key_id->len;

        if ((apdu = iso7816_new(0, U2F_CMD_AUTH, U2F_AUTH_CHECK, (uint16_t)(2 *

            SHA256_DIGEST_LENGTH + sizeof(key_id_len) + key_id_len))) == NULL ||

            iso7816_add(apdu, &challenge, sizeof(challenge)) < 0 ||

            iso7816_add(apdu, &rp_id_hash, sizeof(rp_id_hash)) < 0 ||

            iso7816_add(apdu, &key_id_len, sizeof(key_id_len)) < 0 ||

            iso7816_add(apdu, key_id->ptr, key_id_len) < 0) {

                fido_log_debug("%s: iso7816", __func__);

                r = FIDO_ERR_INTERNAL;

                goto fail;

        }

        if ((reply = malloc(FIDO_MAXMSG)) == NULL) {

                fido_log_debug("%s: malloc", __func__);

                r = FIDO_ERR_INTERNAL;

                goto fail;

        }

        if (fido_tx(dev, CTAP_CMD_MSG, iso7816_ptr(apdu),

            iso7816_len(apdu), ms) < 0) {

                fido_log_debug("%s: fido_tx", __func__);

                r = FIDO_ERR_TX;

                goto fail;

        }

        if (fido_rx(dev, CTAP_CMD_MSG, reply, FIDO_MAXMSG, ms) != 2) {

                fido_log_debug("%s: fido_rx", __func__);

                r = FIDO_ERR_RX;

                goto fail;

        }

        switch ((reply[0] << 8) | reply[1]) {

        case SW_CONDITIONS_NOT_SATISFIED:

                *found = 1; /* key exists */

                break;

        case SW_WRONG_DATA:

        case SW_WRONG_LENGTH:

                *found = 0; /* key does not exist */

                break;

        default:

                /* unexpected sw */

                r = FIDO_ERR_INTERNAL;

                goto fail;

        }

        r = FIDO_OK;

fail:

        iso7816_free(&apdu);

        freezero(reply, FIDO_MAXMSG);

        return (r);

}

static int

parse_auth_reply(fido_blob_t *sig, fido_blob_t *ad, const char *rp_id,

    const unsigned char *reply, size_t len)

{

        uint8_t         flags;

        uint32_t        sigcount;

        if (len < 2 || ((reply[len - 2] << 8) | reply[len - 1]) != SW_NO_ERROR) {

                fido_log_debug("%s: unexpected sw", __func__);

                return (FIDO_ERR_RX);

        }

        len -= 2;

        if (fido_buf_read(&reply, &len, &flags, sizeof(flags)) < 0 ||

            fido_buf_read(&reply, &len, &sigcount, sizeof(sigcount)) < 0) {

                fido_log_debug("%s: fido_buf_read", __func__);

                return (FIDO_ERR_RX);

        }

        if (sig_get(sig, &reply, &len) < 0) {

                fido_log_debug("%s: sig_get", __func__);

                return (FIDO_ERR_RX);

        }

        if (authdata_fake(rp_id, flags, sigcount, ad) < 0) {

                fido_log_debug("%s; authdata_fake", __func__);

                return (FIDO_ERR_RX);

        }

        return (FIDO_OK);

}

static int

do_auth(fido_dev_t *dev, const fido_blob_t *cdh, const char *rp_id,

    const fido_blob_t *key_id, fido_blob_t *sig, fido_blob_t *ad, int *ms)

{

        iso7816_apdu_t  *apdu = NULL;

        unsigned char   *reply = NULL;

        unsigned char    rp_id_hash[SHA256_DIGEST_LENGTH];

        int              reply_len;

        uint8_t          key_id_len;

        int              r;

#ifdef FIDO_FUZZ

        *ms = 0; /* XXX */

#endif

        if (cdh->len != SHA256_DIGEST_LENGTH || key_id->len > UINT8_MAX ||

            rp_id == NULL) {

                r = FIDO_ERR_INVALID_ARGUMENT;

                goto fail;

        }

        memset(&rp_id_hash, 0, sizeof(rp_id_hash));

        if (SHA256((const void *)rp_id, strlen(rp_id),

            rp_id_hash) != rp_id_hash) {

                fido_log_debug("%s: sha256", __func__);

                r = FIDO_ERR_INTERNAL;

                goto fail;

        }

        key_id_len = (uint8_t)key_id->len;

        if ((apdu = iso7816_new(0, U2F_CMD_AUTH, U2F_AUTH_SIGN, (uint16_t)(2 *

            SHA256_DIGEST_LENGTH + sizeof(key_id_len) + key_id_len))) == NULL ||

            iso7816_add(apdu, cdh->ptr, cdh->len) < 0 ||

            iso7816_add(apdu, &rp_id_hash, sizeof(rp_id_hash)) < 0 ||

            iso7816_add(apdu, &key_id_len, sizeof(key_id_len)) < 0 ||

            iso7816_add(apdu, key_id->ptr, key_id_len) < 0) {

                fido_log_debug("%s: iso7816", __func__);

                r = FIDO_ERR_INTERNAL;

                goto fail;

        }

        if ((reply = malloc(FIDO_MAXMSG)) == NULL) {

                fido_log_debug("%s: malloc", __func__);

                r = FIDO_ERR_INTERNAL;

                goto fail;

        }

        do {

                if (fido_tx(dev, CTAP_CMD_MSG, iso7816_ptr(apdu),

                    iso7816_len(apdu), ms) < 0) {

                        fido_log_debug("%s: fido_tx", __func__);

                        r = FIDO_ERR_TX;

                        goto fail;

                }

                if ((reply_len = fido_rx(dev, CTAP_CMD_MSG, reply,

                    FIDO_MAXMSG, ms)) < 2) {

                        fido_log_debug("%s: fido_rx", __func__);

                        r = FIDO_ERR_RX;

                        goto fail;

                }

                if (delay_ms(U2F_PACE_MS, ms) != 0) {

                        fido_log_debug("%s: delay_ms", __func__);

                        r = FIDO_ERR_RX;

                        goto fail;

                }

        } while (((reply[0] << 8) | reply[1]) == SW_CONDITIONS_NOT_SATISFIED);

        if ((r = parse_auth_reply(sig, ad, rp_id, reply,

            (size_t)reply_len)) != FIDO_OK) {

                fido_log_debug("%s: parse_auth_reply", __func__);

                goto fail;

        }

fail:

        iso7816_free(&apdu);

        freezero(reply, FIDO_MAXMSG);

        return (r);

}

static int

cbor_blob_from_ec_point(const uint8_t *ec_point, size_t ec_point_len,

    fido_blob_t *cbor_blob)

{

        es256_pk_t      *pk = NULL;

        cbor_item_t     *pk_cbor = NULL;

        size_t           alloc_len;

        int              ok = -1;

        /* only handle uncompressed points */

        if (ec_point_len != 65 || ec_point[0] != 0x04) {

                fido_log_debug("%s: unexpected format", __func__);

                goto fail;

        }

        if ((pk = es256_pk_new()) == NULL ||

            es256_pk_set_x(pk, &ec_point[1]) < 0 ||

            es256_pk_set_y(pk, &ec_point[33]) < 0) {

                fido_log_debug("%s: es256_pk_set", __func__);

                goto fail;

        }

        if ((pk_cbor = es256_pk_encode(pk, 0)) == NULL) {

                fido_log_debug("%s: es256_pk_encode", __func__);

                goto fail;

        }

        if ((cbor_blob->len = cbor_serialize_alloc(pk_cbor, &cbor_blob->ptr,

            &alloc_len)) != 77) {

                fido_log_debug("%s: cbor_serialize_alloc", __func__);

                goto fail;

        }

        ok = 0;

fail:

        es256_pk_free(&pk);

        if (pk_cbor)

                cbor_decref(&pk_cbor);

        return (ok);

}

static int

encode_cred_attstmt(int cose_alg, const fido_blob_t *x5c,

    const fido_blob_t *sig, fido_blob_t *out)

{

        cbor_item_t             *item = NULL;

        cbor_item_t             *x5c_cbor = NULL;

        const uint8_t            alg_cbor = (uint8_t)(-cose_alg - 1);

        struct cbor_pair         kv[3];

        size_t                   alloc_len;

        int                      ok = -1;

        memset(&kv, 0, sizeof(kv));

        memset(out, 0, sizeof(*out));

        if ((item = cbor_new_definite_map(3)) == NULL) {

                fido_log_debug("%s: cbor_new_definite_map", __func__);

                goto fail;

        }

        if ((kv[0].key = cbor_build_string("alg")) == NULL ||

            (kv[0].value = cbor_build_negint8(alg_cbor)) == NULL ||

            !cbor_map_add(item, kv[0])) {

                fido_log_debug("%s: alg", __func__);

                goto fail;

        }

        if ((kv[1].key = cbor_build_string("sig")) == NULL ||

            (kv[1].value = fido_blob_encode(sig)) == NULL ||

            !cbor_map_add(item, kv[1])) {

                fido_log_debug("%s: sig", __func__);

                goto fail;

        }

        if ((kv[2].key = cbor_build_string("x5c")) == NULL ||

            (kv[2].value = cbor_new_definite_array(1)) == NULL ||

            (x5c_cbor = fido_blob_encode(x5c)) == NULL ||

            !cbor_array_push(kv[2].value, x5c_cbor) ||

            !cbor_map_add(item, kv[2])) {

                fido_log_debug("%s: x5c", __func__);

                goto fail;

        }

        if ((out->len = cbor_serialize_alloc(item, &out->ptr,

            &alloc_len)) == 0) {

                fido_log_debug("%s: cbor_serialize_alloc", __func__);

                goto fail;

        }

        ok = 0;

fail:

        if (item != NULL)

                cbor_decref(&item);

        if (x5c_cbor != NULL)

                cbor_decref(&x5c_cbor);

        for (size_t i = 0; i < nitems(kv); i++) {

                if (kv[i].key)

                        cbor_decref(&kv[i].key);

                if (kv[i].value)

                        cbor_decref(&kv[i].value);

        }

        return (ok);

}

static int

encode_cred_authdata(const char *rp_id, const uint8_t *kh, uint8_t kh_len,

    const uint8_t *pubkey, size_t pubkey_len, fido_blob_t *out)

{

        fido_authdata_t          authdata;

        fido_attcred_raw_t       attcred_raw;

        fido_blob_t              pk_blob;

        fido_blob_t              authdata_blob;

        cbor_item_t             *authdata_cbor = NULL;

        unsigned char           *ptr;

        size_t                   len;

        size_t                   alloc_len;

        int                      ok = -1;

        memset(&pk_blob, 0, sizeof(pk_blob));

        memset(&authdata, 0, sizeof(authdata));

        memset(&authdata_blob, 0, sizeof(authdata_blob));

        memset(out, 0, sizeof(*out));

        if (rp_id == NULL) {

                fido_log_debug("%s: NULL rp_id", __func__);

                goto fail;

        }

        if (cbor_blob_from_ec_point(pubkey, pubkey_len, &pk_blob) < 0) {

                fido_log_debug("%s: cbor_blob_from_ec_point", __func__);

                goto fail;

        }

        if (SHA256((const void *)rp_id, strlen(rp_id),

            authdata.rp_id_hash) != authdata.rp_id_hash) {

                fido_log_debug("%s: sha256", __func__);

                goto fail;

        }

        authdata.flags = (CTAP_AUTHDATA_ATT_CRED | CTAP_AUTHDATA_USER_PRESENT);

        authdata.sigcount = 0;

        memset(&attcred_raw.aaguid, 0, sizeof(attcred_raw.aaguid));

        attcred_raw.id_len = htobe16(kh_len);

        len = authdata_blob.len = sizeof(authdata) + sizeof(attcred_raw) +

            kh_len + pk_blob.len;

        ptr = authdata_blob.ptr = calloc(1, authdata_blob.len);

        fido_log_debug("%s: ptr=%p, len=%zu", __func__, (void *)ptr, len);

        if (authdata_blob.ptr == NULL)

                goto fail;

        if (fido_buf_write(&ptr, &len, &authdata, sizeof(authdata)) < 0 ||

            fido_buf_write(&ptr, &len, &attcred_raw, sizeof(attcred_raw)) < 0 ||

            fido_buf_write(&ptr, &len, kh, kh_len) < 0 ||

            fido_buf_write(&ptr, &len, pk_blob.ptr, pk_blob.len) < 0) {

                fido_log_debug("%s: fido_buf_write", __func__);

                goto fail;

        }

        if ((authdata_cbor = fido_blob_encode(&authdata_blob)) == NULL) {

                fido_log_debug("%s: fido_blob_encode", __func__);

                goto fail;

        }

        if ((out->len = cbor_serialize_alloc(authdata_cbor, &out->ptr,

            &alloc_len)) == 0) {

                fido_log_debug("%s: cbor_serialize_alloc", __func__);

                goto fail;

        }

        ok = 0;

fail:

        if (authdata_cbor)

                cbor_decref(&authdata_cbor);

        fido_blob_reset(&pk_blob);

        fido_blob_reset(&authdata_blob);

        return (ok);

}

static int

parse_register_reply(fido_cred_t *cred, const unsigned char *reply, size_t len)

{

        fido_blob_t      x5c;

        fido_blob_t      sig;

        fido_blob_t      ad;

        fido_blob_t      stmt;

        uint8_t          dummy;

        uint8_t          pubkey[65];

        uint8_t          kh_len = 0;

        uint8_t         *kh = NULL;

        int              r;

        memset(&x5c, 0, sizeof(x5c));

        memset(&sig, 0, sizeof(sig));

        memset(&ad, 0, sizeof(ad));

        memset(&stmt, 0, sizeof(stmt));

        r = FIDO_ERR_RX;

        /* status word */

        if (len < 2 || ((reply[len - 2] << 8) | reply[len - 1]) != SW_NO_ERROR) {

                fido_log_debug("%s: unexpected sw", __func__);

                goto fail;

        }

        len -= 2;

        /* reserved byte */

        if (fido_buf_read(&reply, &len, &dummy, sizeof(dummy)) < 0 ||

            dummy != 0x05) {

                fido_log_debug("%s: reserved byte", __func__);

                goto fail;

        }

        /* pubkey + key handle */

        if (fido_buf_read(&reply, &len, &pubkey, sizeof(pubkey)) < 0 ||

            fido_buf_read(&reply, &len, &kh_len, sizeof(kh_len)) < 0 ||

            (kh = calloc(1, kh_len)) == NULL ||

            fido_buf_read(&reply, &len, kh, kh_len) < 0) {

                fido_log_debug("%s: fido_buf_read", __func__);

                goto fail;

        }

        /* x5c + sig */

        if (x5c_get(&x5c, &reply, &len) < 0 ||

            sig_get(&sig, &reply, &len) < 0) {

                fido_log_debug("%s: x5c || sig", __func__);

                goto fail;

        }

        /* attstmt */

        if (encode_cred_attstmt(COSE_ES256, &x5c, &sig, &stmt) < 0) {

                fido_log_debug("%s: encode_cred_attstmt", __func__);

                goto fail;

        }

        /* authdata */

        if (encode_cred_authdata(cred->rp.id, kh, kh_len, pubkey,

            sizeof(pubkey), &ad) < 0) {

                fido_log_debug("%s: encode_cred_authdata", __func__);

                goto fail;

        }

        if (fido_cred_set_fmt(cred, "fido-u2f") != FIDO_OK ||

            fido_cred_set_authdata(cred, ad.ptr, ad.len) != FIDO_OK ||

            fido_cred_set_attstmt(cred, stmt.ptr, stmt.len) != FIDO_OK) {

                fido_log_debug("%s: fido_cred_set", __func__);

                r = FIDO_ERR_INTERNAL;

                goto fail;

        }

        r = FIDO_OK;

fail:

        freezero(kh, kh_len);

        fido_blob_reset(&x5c);

        fido_blob_reset(&sig);

        fido_blob_reset(&ad);

        fido_blob_reset(&stmt);

        return (r);

}

int

u2f_register(fido_dev_t *dev, fido_cred_t *cred, int *ms)

{

        iso7816_apdu_t  *apdu = NULL;

        unsigned char    rp_id_hash[SHA256_DIGEST_LENGTH];

        unsigned char   *reply = NULL;

        int              reply_len;

        int              found;

        int              r;

        if (cred->rk == FIDO_OPT_TRUE || cred->uv == FIDO_OPT_TRUE) {

                fido_log_debug("%s: rk=%d, uv=%d", __func__, cred->rk,

                    cred->uv);

                return (FIDO_ERR_UNSUPPORTED_OPTION);

        }

        if (cred->type != COSE_ES256 || cred->cdh.ptr == NULL ||

            cred->rp.id == NULL || cred->cdh.len != SHA256_DIGEST_LENGTH) {

                fido_log_debug("%s: type=%d, cdh=(%p,%zu)" , __func__,

                    cred->type, (void *)cred->cdh.ptr, cred->cdh.len);

                return (FIDO_ERR_INVALID_ARGUMENT);

        }

        for (size_t i = 0; i < cred->excl.len; i++) {

                if ((r = key_lookup(dev, cred->rp.id, &cred->excl.ptr[i],

                    &found, ms)) != FIDO_OK) {

                        fido_log_debug("%s: key_lookup", __func__);

                        return (r);

                }

                if (found) {

                        if ((r = send_dummy_register(dev, ms)) != FIDO_OK) {

                                fido_log_debug("%s: send_dummy_register",

                                    __func__);

                                return (r);

                        }

                        return (FIDO_ERR_CREDENTIAL_EXCLUDED);

                }

        }

        memset(&rp_id_hash, 0, sizeof(rp_id_hash));

        if (SHA256((const void *)cred->rp.id, strlen(cred->rp.id),

            rp_id_hash) != rp_id_hash) {

                fido_log_debug("%s: sha256", __func__);

                return (FIDO_ERR_INTERNAL);

        }

        if ((apdu = iso7816_new(0, U2F_CMD_REGISTER, 0, 2 *

            SHA256_DIGEST_LENGTH)) == NULL ||

            iso7816_add(apdu, cred->cdh.ptr, cred->cdh.len) < 0 ||

            iso7816_add(apdu, rp_id_hash, sizeof(rp_id_hash)) < 0) {

                fido_log_debug("%s: iso7816", __func__);

                r = FIDO_ERR_INTERNAL;

                goto fail;

        }

        if ((reply = malloc(FIDO_MAXMSG)) == NULL) {

                fido_log_debug("%s: malloc", __func__);

                r = FIDO_ERR_INTERNAL;

                goto fail;

        }

        do {

                if (fido_tx(dev, CTAP_CMD_MSG, iso7816_ptr(apdu),

                    iso7816_len(apdu), ms) < 0) {

                        fido_log_debug("%s: fido_tx", __func__);

                        r = FIDO_ERR_TX;

                        goto fail;

                }

                if ((reply_len = fido_rx(dev, CTAP_CMD_MSG, reply,

                    FIDO_MAXMSG, ms)) < 2) {

                        fido_log_debug("%s: fido_rx", __func__);

                        r = FIDO_ERR_RX;

                        goto fail;

                }

                if (delay_ms(U2F_PACE_MS, ms) != 0) {

                        fido_log_debug("%s: delay_ms", __func__);

                        r = FIDO_ERR_RX;

                        goto fail;

                }

        } while (((reply[0] << 8) | reply[1]) == SW_CONDITIONS_NOT_SATISFIED);

        if ((r = parse_register_reply(cred, reply,

            (size_t)reply_len)) != FIDO_OK) {

                fido_log_debug("%s: parse_register_reply", __func__);

                goto fail;

        }

fail:

        iso7816_free(&apdu);

        freezero(reply, FIDO_MAXMSG);

        return (r);

}

static int

u2f_authenticate_single(fido_dev_t *dev, const fido_blob_t *key_id,

    fido_assert_t *fa, size_t idx, int *ms)

{

        fido_blob_t     sig;

        fido_blob_t     ad;

        int             found;

        int             r;

        memset(&sig, 0, sizeof(sig));

        memset(&ad, 0, sizeof(ad));

        if ((r = key_lookup(dev, fa->rp_id, key_id, &found, ms)) != FIDO_OK) {

                fido_log_debug("%s: key_lookup", __func__);

                goto fail;

        }

        if (!found) {

                fido_log_debug("%s: not found", __func__);

                r = FIDO_ERR_CREDENTIAL_EXCLUDED;

                goto fail;

        }

        if (fido_blob_set(&fa->stmt[idx].id, key_id->ptr, key_id->len) < 0) {

                fido_log_debug("%s: fido_blob_set", __func__);

                r = FIDO_ERR_INTERNAL;

                goto fail;

        }

        if (fa->up == FIDO_OPT_FALSE) {

                fido_log_debug("%s: checking for key existence only", __func__);

                r = FIDO_ERR_USER_PRESENCE_REQUIRED;

                goto fail;

        }

        if ((r = do_auth(dev, &fa->cdh, fa->rp_id, key_id, &sig, &ad,

            ms)) != FIDO_OK) {

                fido_log_debug("%s: do_auth", __func__);

                goto fail;

        }

        if (fido_assert_set_authdata(fa, idx, ad.ptr, ad.len) != FIDO_OK ||

            fido_assert_set_sig(fa, idx, sig.ptr, sig.len) != FIDO_OK) {

                fido_log_debug("%s: fido_assert_set", __func__);

                r = FIDO_ERR_INTERNAL;

                goto fail;

        }

        r = FIDO_OK;

fail:

        fido_blob_reset(&sig);

        fido_blob_reset(&ad);

        return (r);

}

int

u2f_authenticate(fido_dev_t *dev, fido_assert_t *fa, int *ms)

{

        size_t  nfound = 0;

        size_t  nauth_ok = 0;

        int     r;

        if (fa->uv == FIDO_OPT_TRUE || fa->allow_list.ptr == NULL) {

                fido_log_debug("%s: uv=%d, allow_list=%p", __func__, fa->uv,

                    (void *)fa->allow_list.ptr);

                return (FIDO_ERR_UNSUPPORTED_OPTION);

        }

        if ((r = fido_assert_set_count(fa, fa->allow_list.len)) != FIDO_OK) {

                fido_log_debug("%s: fido_assert_set_count", __func__);

                return (r);

        }

        for (size_t i = 0; i < fa->allow_list.len; i++) {

                switch ((r = u2f_authenticate_single(dev,

                    &fa->allow_list.ptr[i], fa, nfound, ms))) {

                case FIDO_OK:

                        nauth_ok++;

                        FALLTHROUGH

                case FIDO_ERR_USER_PRESENCE_REQUIRED:

                        nfound++;

                        break;

                default:

                        if (r != FIDO_ERR_CREDENTIAL_EXCLUDED) {

                                fido_log_debug("%s: u2f_authenticate_single",

                                    __func__);

                                return (r);

                        }

                        /* ignore credentials that don't exist */

                }

        }

        fa->stmt_len = nfound;

        if (nfound == 0)

                return (FIDO_ERR_NO_CREDENTIALS);

        if (nauth_ok == 0)

                return (FIDO_ERR_USER_PRESENCE_REQUIRED);

        return (FIDO_OK);

}

int

u2f_get_touch_begin(fido_dev_t *dev, int *ms)

{

        iso7816_apdu_t  *apdu = NULL;

        const char      *clientdata = FIDO_DUMMY_CLIENTDATA;

        const char      *rp_id = FIDO_DUMMY_RP_ID;

        unsigned char   *reply = NULL;

        unsigned char    clientdata_hash[SHA256_DIGEST_LENGTH];

        unsigned char    rp_id_hash[SHA256_DIGEST_LENGTH];

        int              r;

        memset(&clientdata_hash, 0, sizeof(clientdata_hash));

        memset(&rp_id_hash, 0, sizeof(rp_id_hash));

        if (SHA256((const void *)clientdata, strlen(clientdata),

            clientdata_hash) != clientdata_hash || SHA256((const void *)rp_id,

            strlen(rp_id), rp_id_hash) != rp_id_hash) {

                fido_log_debug("%s: sha256", __func__);

                return (FIDO_ERR_INTERNAL);

        }

        if ((apdu = iso7816_new(0, U2F_CMD_REGISTER, 0, 2 *

            SHA256_DIGEST_LENGTH)) == NULL ||

            iso7816_add(apdu, clientdata_hash, sizeof(clientdata_hash)) < 0 ||

            iso7816_add(apdu, rp_id_hash, sizeof(rp_id_hash)) < 0) {

                fido_log_debug("%s: iso7816", __func__);

                r = FIDO_ERR_INTERNAL;

                goto fail;

        }

        if ((reply = malloc(FIDO_MAXMSG)) == NULL) {

                fido_log_debug("%s: malloc", __func__);

                r =  FIDO_ERR_INTERNAL;

                goto fail;

        }

        if (dev->attr.flags & FIDO_CAP_WINK) {

                fido_tx(dev, CTAP_CMD_WINK, NULL, 0, ms);

                fido_rx(dev, CTAP_CMD_WINK, reply, FIDO_MAXMSG, ms);

        }

        if (fido_tx(dev, CTAP_CMD_MSG, iso7816_ptr(apdu),

            iso7816_len(apdu), ms) < 0) {

                fido_log_debug("%s: fido_tx", __func__);

                r = FIDO_ERR_TX;

                goto fail;

        }

        r = FIDO_OK;

fail:

        iso7816_free(&apdu);

        freezero(reply, FIDO_MAXMSG);

        return (r);

}

int

u2f_get_touch_status(fido_dev_t *dev, int *touched, int *ms)

{

        unsigned char   *reply;

        int              reply_len;

        int              r;

        if ((reply = malloc(FIDO_MAXMSG)) == NULL) {

                fido_log_debug("%s: malloc", __func__);

                r =  FIDO_ERR_INTERNAL;

                goto out;

        }

        if ((reply_len = fido_rx(dev, CTAP_CMD_MSG, reply, FIDO_MAXMSG,

            ms)) < 2) {

                fido_log_debug("%s: fido_rx", __func__);

                r = FIDO_OK; /* ignore */

                goto out;

        }

        switch ((reply[reply_len - 2] << 8) | reply[reply_len - 1]) {

        case SW_CONDITIONS_NOT_SATISFIED:

                if ((r = u2f_get_touch_begin(dev, ms)) != FIDO_OK) {

                        fido_log_debug("%s: u2f_get_touch_begin", __func__);

                        goto out;

                }

                *touched = 0;

                break;

        case SW_NO_ERROR:

                *touched = 1;

                break;

        default:

                fido_log_debug("%s: unexpected sw", __func__);

                r = FIDO_ERR_RX;

                goto out;

        }

        r = FIDO_OK;

out:

        freezero(reply, FIDO_MAXMSG);

        return (r);

}