/libfido2/src/cbor.c

Source
/*
 * Copyright (c) 2018-2025 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/hmac.h>
#include <openssl/sha.h>
#include "fido.h"

static int
check_key_type(cbor_item_t *item)
{
        if (item->type == CBOR_TYPE_UINT || item->type == CBOR_TYPE_NEGINT ||
            item->type == CBOR_TYPE_STRING)
                return (0);

        fido_log_debug("%s: invalid type: %d", __func__, item->type);

        return (-1);
}

/*
 * Validate CTAP2 canonical CBOR encoding rules for maps.
 */
static int
ctap_check_cbor(cbor_item_t *prev, cbor_item_t *curr)
{
        size_t  curr_len;
        size_t  prev_len;

        if (check_key_type(prev) < 0 || check_key_type(curr) < 0)
                return (-1);

        if (prev->type != curr->type) {
                if (prev->type < curr->type)
                        return (0);
                fido_log_debug("%s: unsorted types", __func__);
                return (-1);
        }

        if (curr->type == CBOR_TYPE_UINT || curr->type == CBOR_TYPE_NEGINT) {
                if (cbor_int_get_width(curr) >= cbor_int_get_width(prev) &&
                    cbor_get_int(curr) > cbor_get_int(prev))
                        return (0);
        } else {
                curr_len = cbor_string_length(curr);
                prev_len = cbor_string_length(prev);

                if (curr_len > prev_len || (curr_len == prev_len &&
                    memcmp(cbor_string_handle(prev), cbor_string_handle(curr),
                    curr_len) < 0))
                        return (0);
        }

        fido_log_debug("%s: invalid cbor", __func__);

        return (-1);
}

int
cbor_map_iter(const cbor_item_t *item, void *arg, int(*f)(const cbor_item_t *,
    const cbor_item_t *, void *))
{
        struct cbor_pair        *v;
        size_t                   n;

        if ((v = cbor_map_handle(item)) == NULL) {
                fido_log_debug("%s: cbor_map_handle", __func__);
                return (-1);
        }

        n = cbor_map_size(item);

        for (size_t i = 0; i < n; i++) {
                if (v[i].key == NULL || v[i].value == NULL) {
                        fido_log_debug("%s: key=%p, value=%p for i=%zu",
                            __func__, (void *)v[i].key, (void *)v[i].value, i);
                        return (-1);
                }
                if (i && ctap_check_cbor(v[i - 1].key, v[i].key) < 0) {
                        fido_log_debug("%s: ctap_check_cbor", __func__);
                        return (-1);
                }
                if (f(v[i].key, v[i].value, arg) < 0) {
                        fido_log_debug("%s: iterator < 0 on i=%zu", __func__,
                            i);
                        return (-1);
                }
        }

        return (0);
}

int
cbor_array_iter(const cbor_item_t *item, void *arg, int(*f)(const cbor_item_t *,
    void *))
{
        cbor_item_t     **v;
        size_t            n;

        if ((v = cbor_array_handle(item)) == NULL) {
                fido_log_debug("%s: cbor_array_handle", __func__);
                return (-1);
        }

        n = cbor_array_size(item);

        for (size_t i = 0; i < n; i++)
                if (v[i] == NULL || f(v[i], arg) < 0) {
                        fido_log_debug("%s: iterator < 0 on i=%zu,%p",
                            __func__, i, (void *)v[i]);
                        return (-1);
                }

        return (0);
}

int
cbor_parse_reply(const unsigned char *blob, size_t blob_len, void *arg,
    int(*parser)(const cbor_item_t *, const cbor_item_t *, void *))
{
        cbor_item_t             *item = NULL;
        struct cbor_load_result  cbor;
        int                      r;

        if (blob_len < 1) {
                fido_log_debug("%s: blob_len=%zu", __func__, blob_len);
                r = FIDO_ERR_RX;
                goto fail;
        }

        if (blob[0] != FIDO_OK) {
                fido_log_debug("%s: blob[0]=0x%02x", __func__, blob[0]);
                r = blob[0];
                goto fail;
        }

        if ((item = cbor_load(blob + 1, blob_len - 1, &cbor)) == NULL) {
                fido_log_debug("%s: cbor_load", __func__);
                r = FIDO_ERR_RX_NOT_CBOR;
                goto fail;
        }

        if (cbor_isa_map(item) == false ||
            cbor_map_is_definite(item) == false) {
                fido_log_debug("%s: cbor type", __func__);
                r = FIDO_ERR_RX_INVALID_CBOR;
                goto fail;
        }

        if (cbor_map_iter(item, arg, parser) < 0) {
                fido_log_debug("%s: cbor_map_iter", __func__);
                r = FIDO_ERR_RX_INVALID_CBOR;
                goto fail;
        }

        r = FIDO_OK;
fail:
        if (item != NULL)
                cbor_decref(&item);

        return (r);
}

void
cbor_vector_free(cbor_item_t **item, size_t len)
{
        for (size_t i = 0; i < len; i++)
                if (item[i] != NULL)
                        cbor_decref(&item[i]);
}

int
cbor_bytestring_copy(const cbor_item_t *item, unsigned char **buf, size_t *len)
{
        if (*buf != NULL || *len != 0) {
                fido_log_debug("%s: dup", __func__);
                return (-1);
        }

        if (cbor_isa_bytestring(item) == false ||
            cbor_bytestring_is_definite(item) == false) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        *len = cbor_bytestring_length(item);
        if ((*buf = malloc(*len)) == NULL) {
                *len = 0;
                return (-1);
        }

        memcpy(*buf, cbor_bytestring_handle(item), *len);

        return (0);
}

int
cbor_string_copy(const cbor_item_t *item, char **str)
{
        size_t len;

        if (*str != NULL) {
                fido_log_debug("%s: dup", __func__);
                return (-1);
        }

        if (cbor_isa_string(item) == false ||
            cbor_string_is_definite(item) == false) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        if ((len = cbor_string_length(item)) == SIZE_MAX ||
            (*str = malloc(len + 1)) == NULL)
                return (-1);

        memcpy(*str, cbor_string_handle(item), len);
        (*str)[len] = '\0';

        return (0);
}

int
cbor_add_bytestring(cbor_item_t *item, const char *key,
    const unsigned char *value, size_t value_len)
{
        struct cbor_pair pair;
        int ok = -1;

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

        if ((pair.key = cbor_build_string(key)) == NULL ||
            (pair.value = cbor_build_bytestring(value, value_len)) == NULL) {
                fido_log_debug("%s: cbor_build", __func__);
                goto fail;
        }

        if (!cbor_map_add(item, pair)) {
                fido_log_debug("%s: cbor_map_add", __func__);
                goto fail;
        }

        ok = 0;
fail:
        if (pair.key)
                cbor_decref(&pair.key);
        if (pair.value)
                cbor_decref(&pair.value);

        return (ok);
}

int
cbor_add_string(cbor_item_t *item, const char *key, const char *value)
{
        struct cbor_pair pair;
        int ok = -1;

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

        if ((pair.key = cbor_build_string(key)) == NULL ||
            (pair.value = cbor_build_string(value)) == NULL) {
                fido_log_debug("%s: cbor_build", __func__);
                goto fail;
        }

        if (!cbor_map_add(item, pair)) {
                fido_log_debug("%s: cbor_map_add", __func__);
                goto fail;
        }

        ok = 0;
fail:
        if (pair.key)
                cbor_decref(&pair.key);
        if (pair.value)
                cbor_decref(&pair.value);

        return (ok);
}

int
cbor_add_bool(cbor_item_t *item, const char *key, fido_opt_t value)
{
        struct cbor_pair pair;
        int ok = -1;

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

        if ((pair.key = cbor_build_string(key)) == NULL ||
            (pair.value = cbor_build_bool(value == FIDO_OPT_TRUE)) == NULL) {
                fido_log_debug("%s: cbor_build", __func__);
                goto fail;
        }

        if (!cbor_map_add(item, pair)) {
                fido_log_debug("%s: cbor_map_add", __func__);
                goto fail;
        }

        ok = 0;
fail:
        if (pair.key)
                cbor_decref(&pair.key);
        if (pair.value)
                cbor_decref(&pair.value);

        return (ok);
}

static int
cbor_add_uint8(cbor_item_t *item, const char *key, uint8_t value)
{
        struct cbor_pair pair;
        int ok = -1;

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

        if ((pair.key = cbor_build_string(key)) == NULL ||
            (pair.value = cbor_build_uint8(value)) == NULL) {
                fido_log_debug("%s: cbor_build", __func__);
                goto fail;
        }

        if (!cbor_map_add(item, pair)) {
                fido_log_debug("%s: cbor_map_add", __func__);
                goto fail;
        }

        ok = 0;
fail:
        if (pair.key)
                cbor_decref(&pair.key);
        if (pair.value)
                cbor_decref(&pair.value);

        return (ok);
}

static int
cbor_add_arg(cbor_item_t *item, uint8_t n, cbor_item_t *arg)
{
        struct cbor_pair pair;
        int ok = -1;

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

        if (arg == NULL)
                return (0); /* empty argument */

        if ((pair.key = cbor_build_uint8(n)) == NULL) {
                fido_log_debug("%s: cbor_build", __func__);
                goto fail;
        }

        pair.value = arg;

        if (!cbor_map_add(item, pair)) {
                fido_log_debug("%s: cbor_map_add", __func__);
                goto fail;
        }

        ok = 0;
fail:
        if (pair.key)
                cbor_decref(&pair.key);

        return (ok);
}

cbor_item_t *
cbor_flatten_vector(cbor_item_t *argv[], size_t argc)
{
        cbor_item_t     *map;
        uint8_t          i;

        if (argc > UINT8_MAX - 1)
                return (NULL);

        if ((map = cbor_new_definite_map(argc)) == NULL)
                return (NULL);

        for (i = 0; i < argc; i++)
                if (cbor_add_arg(map, (uint8_t)(i + 1), argv[i]) < 0)
                        break;

        if (i != argc) {
                cbor_decref(&map);
                map = NULL;
        }

        return (map);
}

int
cbor_build_frame(uint8_t cmd, cbor_item_t *argv[], size_t argc, fido_blob_t *f)
{
        cbor_item_t     *flat = NULL;
        unsigned char   *cbor = NULL;
        size_t           cbor_len;
        size_t           cbor_alloc_len;
        int              ok = -1;

        if ((flat = cbor_flatten_vector(argv, argc)) == NULL)
                goto fail;

        cbor_len = cbor_serialize_alloc(flat, &cbor, &cbor_alloc_len);
        if (cbor_len == 0 || cbor_len == SIZE_MAX) {
                fido_log_debug("%s: cbor_len=%zu", __func__, cbor_len);
                goto fail;
        }

        if ((f->ptr = malloc(cbor_len + 1)) == NULL)
                goto fail;

        f->len = cbor_len + 1;
        f->ptr[0] = cmd;
        memcpy(f->ptr + 1, cbor, f->len - 1);

        ok = 0;
fail:
        if (flat != NULL)
                cbor_decref(&flat);

        free(cbor);

        return (ok);
}

cbor_item_t *
cbor_encode_rp_entity(const fido_rp_t *rp)
{
        cbor_item_t *item = NULL;

        if ((item = cbor_new_definite_map(2)) == NULL)
                return (NULL);

        if ((rp->id && cbor_add_string(item, "id", rp->id) < 0) ||
            (rp->name && cbor_add_string(item, "name", rp->name) < 0)) {
                cbor_decref(&item);
                return (NULL);
        }

        return (item);
}

cbor_item_t *
cbor_encode_user_entity(const fido_user_t *user)
{
        cbor_item_t             *item = NULL;
        const fido_blob_t       *id = &user->id;
        const char              *display = user->display_name;

        if ((item = cbor_new_definite_map(4)) == NULL)
                return (NULL);

        if ((id->ptr && cbor_add_bytestring(item, "id", id->ptr, id->len) < 0) ||
            (user->icon && cbor_add_string(item, "icon", user->icon) < 0) ||
            (user->name && cbor_add_string(item, "name", user->name) < 0) ||
            (display && cbor_add_string(item, "displayName", display) < 0)) {
                cbor_decref(&item);
                return (NULL);
        }

        return (item);
}

cbor_item_t *
cbor_encode_pubkey_param(int cose_alg)
{
        cbor_item_t             *item = NULL;
        cbor_item_t             *body = NULL;
        struct cbor_pair         alg;
        int                      ok = -1;

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

        if ((item = cbor_new_definite_array(1)) == NULL ||
            (body = cbor_new_definite_map(2)) == NULL ||
            cose_alg > -1 || cose_alg < INT16_MIN)
                goto fail;

        alg.key = cbor_build_string("alg");

        if (-cose_alg - 1 > UINT8_MAX)
                alg.value = cbor_build_negint16((uint16_t)(-cose_alg - 1));
        else
                alg.value = cbor_build_negint8((uint8_t)(-cose_alg - 1));

        if (alg.key == NULL || alg.value == NULL) {
                fido_log_debug("%s: cbor_build", __func__);
                goto fail;
        }

        if (cbor_map_add(body, alg) == false ||
            cbor_add_string(body, "type", "public-key") < 0 ||
            cbor_array_push(item, body) == false)
                goto fail;

        ok  = 0;
fail:
        if (ok < 0) {
                if (item != NULL) {
                        cbor_decref(&item);
                        item = NULL;
                }
        }

        if (body != NULL)
                cbor_decref(&body);
        if (alg.key != NULL)
                cbor_decref(&alg.key);
        if (alg.value != NULL)
                cbor_decref(&alg.value);

        return (item);
}

cbor_item_t *
cbor_encode_pubkey(const fido_blob_t *pubkey)
{
        cbor_item_t *cbor_key = NULL;

        if ((cbor_key = cbor_new_definite_map(2)) == NULL ||
            cbor_add_bytestring(cbor_key, "id", pubkey->ptr, pubkey->len) < 0 ||
            cbor_add_string(cbor_key, "type", "public-key") < 0) {
                if (cbor_key)
                        cbor_decref(&cbor_key);
                return (NULL);
        }

        return (cbor_key);
}

cbor_item_t *
cbor_encode_pubkey_list(const fido_blob_array_t *list)
{
        cbor_item_t     *array = NULL;
        cbor_item_t     *key = NULL;

        if ((array = cbor_new_definite_array(list->len)) == NULL)
                goto fail;

        for (size_t i = 0; i < list->len; i++) {
                if ((key = cbor_encode_pubkey(&list->ptr[i])) == NULL ||
                    cbor_array_push(array, key) == false)
                        goto fail;
                cbor_decref(&key);
        }

        return (array);
fail:
        if (key != NULL)
                cbor_decref(&key);
        if (array != NULL)
                cbor_decref(&array);

        return (NULL);
}

cbor_item_t *
cbor_encode_str_array(const fido_str_array_t *a)
{
        cbor_item_t     *array = NULL;
        cbor_item_t     *entry = NULL;

        if ((array = cbor_new_definite_array(a->len)) == NULL)
                goto fail;

        for (size_t i = 0; i < a->len; i++) {
                if ((entry = cbor_build_string(a->ptr[i])) == NULL ||
                    cbor_array_push(array, entry) == false)
                        goto fail;
                cbor_decref(&entry);
        }

        return (array);
fail:
        if (entry != NULL)
                cbor_decref(&entry);
        if (array != NULL)
                cbor_decref(&array);

        return (NULL);
}

static int
cbor_encode_largeblob_key_ext(cbor_item_t *map)
{
        if (map == NULL ||
            cbor_add_bool(map, "largeBlobKey", FIDO_OPT_TRUE) < 0)
                return (-1);

        return (0);
}

static int
cbor_encode_hmac_secret_param(const char *key, const fido_dev_t *dev,
    cbor_item_t *item, const fido_blob_t *ecdh, const es256_pk_t *pk,
    const fido_blob_t *salt)
{
        cbor_item_t             *param = NULL;
        cbor_item_t             *argv[4];
        struct cbor_pair         pair;
        fido_blob_t             *enc = NULL;
        uint8_t                  prot;
        int                      r;

        memset(argv, 0, sizeof(argv));
        memset(&pair, 0, sizeof(pair));

        if (item == NULL || ecdh == NULL || pk == NULL || salt->ptr == NULL) {
                fido_log_debug("%s: ecdh=%p, pk=%p, salt->ptr=%p", __func__,
                    (const void *)ecdh, (const void *)pk,
                    (const void *)salt->ptr);
                r = FIDO_ERR_INTERNAL;
                goto fail;
        }

        if (salt->len != 32 && salt->len != 64) {
                fido_log_debug("%s: salt->len=%zu", __func__, salt->len);
                r = FIDO_ERR_INTERNAL;
                goto fail;
        }

        if ((enc = fido_blob_new()) == NULL ||
            aes256_cbc_enc(dev, ecdh, salt, enc) < 0) {
                fido_log_debug("%s: aes256_cbc_enc", __func__);
                r = FIDO_ERR_INTERNAL;
                goto fail;
        }

        if ((prot = fido_dev_get_pin_protocol(dev)) == 0) {
                fido_log_debug("%s: fido_dev_get_pin_protocol", __func__);
                r = FIDO_ERR_INTERNAL;
                goto fail;
        }

        /* XXX not pin, but salt */
        if ((argv[0] = es256_pk_encode(pk, 1)) == NULL ||
            (argv[1] = fido_blob_encode(enc)) == NULL ||
            (argv[2] = cbor_encode_pin_auth(dev, ecdh, enc)) == NULL ||
            (prot != 1 && (argv[3] = cbor_build_uint8(prot)) == NULL)) {
                fido_log_debug("%s: cbor encode", __func__);
                r = FIDO_ERR_INTERNAL;
                goto fail;
        }

        if ((param = cbor_flatten_vector(argv, nitems(argv))) == NULL) {
                fido_log_debug("%s: cbor_flatten_vector", __func__);
                r = FIDO_ERR_INTERNAL;
                goto fail;
        }

        if ((pair.key = cbor_build_string(key)) == NULL) {
                fido_log_debug("%s: cbor_build", __func__);
                r = FIDO_ERR_INTERNAL;
                goto fail;
        }

        pair.value = param;

        if (!cbor_map_add(item, pair)) {
                fido_log_debug("%s: cbor_map_add", __func__);
                r = FIDO_ERR_INTERNAL;
                goto fail;
        }

        r = FIDO_OK;

fail:
        cbor_vector_free(argv, nitems(argv));

        if (param != NULL)
                cbor_decref(&param);
        if (pair.key != NULL)
                cbor_decref(&pair.key);

        fido_blob_free(&enc);

        return (r);
}

cbor_item_t *
cbor_encode_cred_ext(const fido_dev_t *dev, const fido_cred_extin_t *ext,
    const fido_blob_t *ecdh, const es256_pk_t *pk)
{
        cbor_item_t *item = NULL;
        size_t size = 0;

        if (ext->attr.mask & FIDO_EXT_CRED_BLOB)
                size++;
        if (ext->attr.mask & FIDO_EXT_HMAC_SECRET)
                size++;
        if (ext->attr.mask & FIDO_EXT_CRED_PROTECT)
                size++;
        if (ext->attr.mask & FIDO_EXT_LARGEBLOB_KEY)
                size++;
        if (ext->attr.mask & FIDO_EXT_MINPINLEN)
                size++;
        if (ext->attr.mask & FIDO_EXT_HMAC_SECRET_MC)
                size++;
        if (ext->attr.mask & FIDO_EXT_PAYMENT)
                size++;

        if (size == 0 || (item = cbor_new_definite_map(size)) == NULL)
                return (NULL);

        if (ext->attr.mask & FIDO_EXT_CRED_BLOB) {
                if (cbor_add_bytestring(item, "credBlob", ext->blob.ptr,
                    ext->blob.len) < 0) {
                        cbor_decref(&item);
                        return (NULL);
                }
        }
        if (ext->attr.mask & FIDO_EXT_CRED_PROTECT) {
                if (ext->attr.prot < 0 || ext->attr.prot > UINT8_MAX ||
                    cbor_add_uint8(item, "credProtect",
                    (uint8_t)ext->attr.prot) < 0) {
                        cbor_decref(&item);
                        return (NULL);
                }
        }
        if (ext->attr.mask & FIDO_EXT_HMAC_SECRET) {
                if (cbor_add_bool(item, "hmac-secret", FIDO_OPT_TRUE) < 0) {
                        cbor_decref(&item);
                        return (NULL);
                }
        }
        if (ext->attr.mask & FIDO_EXT_LARGEBLOB_KEY) {
                if (cbor_encode_largeblob_key_ext(item) < 0) {
                        cbor_decref(&item);
                        return (NULL);
                }
        }
        if (ext->attr.mask & FIDO_EXT_MINPINLEN) {
                if (cbor_add_bool(item, "minPinLength", FIDO_OPT_TRUE) < 0) {
                        cbor_decref(&item);
                        return (NULL);
                }
        }
        if (ext->attr.mask & FIDO_EXT_HMAC_SECRET_MC) {
                if (cbor_encode_hmac_secret_param("hmac-secret-mc", dev, item,
                    ecdh, pk, &ext->hmac_salt) < 0) {
                        cbor_decref(&item);
                        return (NULL);
                }
        }
        if (ext->attr.mask & FIDO_EXT_PAYMENT) {
                if (cbor_add_bool(item, "thirdPartyPayment",
                    FIDO_OPT_TRUE) < 0) {
                        cbor_decref(&item);
                        return (NULL);
                }
        }

        return (item);
}

cbor_item_t *
cbor_encode_cred_opt(fido_opt_t rk, fido_opt_t uv)
{
        cbor_item_t *item = NULL;

        if ((item = cbor_new_definite_map(2)) == NULL)
                return (NULL);
        if ((rk != FIDO_OPT_OMIT && cbor_add_bool(item, "rk", rk) < 0) ||
            (uv != FIDO_OPT_OMIT && cbor_add_bool(item, "uv", uv) < 0)) {
                cbor_decref(&item);
                return (NULL);
        }

        return (item);
}

cbor_item_t *
cbor_encode_assert_opt(fido_opt_t up, fido_opt_t uv)
{
        cbor_item_t *item = NULL;

        if ((item = cbor_new_definite_map(2)) == NULL)
                return (NULL);
        if ((up != FIDO_OPT_OMIT && cbor_add_bool(item, "up", up) < 0) ||
            (uv != FIDO_OPT_OMIT && cbor_add_bool(item, "uv", uv) < 0)) {
                cbor_decref(&item);
                return (NULL);
        }

        return (item);
}

cbor_item_t *
cbor_encode_pin_auth(const fido_dev_t *dev, const fido_blob_t *secret,
    const fido_blob_t *data)
{
        const EVP_MD    *md = NULL;
        unsigned char    dgst[SHA256_DIGEST_LENGTH];
        unsigned int     dgst_len;
        size_t           outlen;
        uint8_t          prot;
        fido_blob_t      key;

        key.ptr = secret->ptr;
        key.len = secret->len;

        if ((prot = fido_dev_get_pin_protocol(dev)) == 0) {
                fido_log_debug("%s: fido_dev_get_pin_protocol", __func__);
                return (NULL);
        }

        /* select hmac portion of the shared secret */
        if (prot == CTAP_PIN_PROTOCOL2 && key.len > 32)
                key.len = 32;

        if ((md = EVP_sha256()) == NULL || HMAC(md, key.ptr,
            (int)key.len, data->ptr, data->len, dgst,
            &dgst_len) == NULL || dgst_len != SHA256_DIGEST_LENGTH)
                return (NULL);

        outlen = (prot == CTAP_PIN_PROTOCOL1) ? 16 : dgst_len;

        return (cbor_build_bytestring(dgst, outlen));
}

cbor_item_t *
cbor_encode_pin_opt(const fido_dev_t *dev)
{
        uint8_t     prot;

        if ((prot = fido_dev_get_pin_protocol(dev)) == 0) {
                fido_log_debug("%s: fido_dev_get_pin_protocol", __func__);
                return (NULL);
        }

        return (cbor_build_uint8(prot));
}

cbor_item_t *
cbor_encode_change_pin_auth(const fido_dev_t *dev, const fido_blob_t *secret,
    const fido_blob_t *new_pin_enc, const fido_blob_t *pin_hash_enc)
{
        unsigned char    dgst[SHA256_DIGEST_LENGTH];
        unsigned int     dgst_len;
        cbor_item_t     *item = NULL;
        const EVP_MD    *md = NULL;
        HMAC_CTX        *ctx = NULL;
        fido_blob_t      key;
        uint8_t          prot;
        size_t           outlen;

        key.ptr = secret->ptr;
        key.len = secret->len;

        if ((prot = fido_dev_get_pin_protocol(dev)) == 0) {
                fido_log_debug("%s: fido_dev_get_pin_protocol", __func__);
                goto fail;
        }

        if (prot == CTAP_PIN_PROTOCOL2 && key.len > 32)
                key.len = 32;

        if ((ctx = HMAC_CTX_new()) == NULL ||
            (md = EVP_sha256())  == NULL ||
            HMAC_Init_ex(ctx, key.ptr, (int)key.len, md, NULL) == 0 ||
            HMAC_Update(ctx, new_pin_enc->ptr, new_pin_enc->len) == 0 ||
            HMAC_Update(ctx, pin_hash_enc->ptr, pin_hash_enc->len) == 0 ||
            HMAC_Final(ctx, dgst, &dgst_len) == 0 ||
            dgst_len != SHA256_DIGEST_LENGTH) {
                fido_log_debug("%s: HMAC", __func__);
                goto fail;
        }

        outlen = (prot == CTAP_PIN_PROTOCOL1) ? 16 : dgst_len;

        if ((item = cbor_build_bytestring(dgst, outlen)) == NULL) {
                fido_log_debug("%s: cbor_build_bytestring", __func__);
                goto fail;
        }

fail:
        HMAC_CTX_free(ctx);

        return (item);
}

cbor_item_t *
cbor_encode_assert_ext(fido_dev_t *dev, const fido_assert_ext_t *ext,
    const fido_blob_t *ecdh, const es256_pk_t *pk)
{
        cbor_item_t *item = NULL;
        size_t size = 0;

        if (ext->mask & FIDO_EXT_CRED_BLOB)
                size++;
        if (ext->mask & FIDO_EXT_HMAC_SECRET)
                size++;
        if (ext->mask & FIDO_EXT_LARGEBLOB_KEY)
                size++;
        if (ext->mask & FIDO_EXT_PAYMENT)
                size++;
        if (size == 0 || (item = cbor_new_definite_map(size)) == NULL)
                return (NULL);

        if (ext->mask & FIDO_EXT_CRED_BLOB) {
                if (cbor_add_bool(item, "credBlob", FIDO_OPT_TRUE) < 0) {
                        cbor_decref(&item);
                        return (NULL);
                }
        }
        if (ext->mask & FIDO_EXT_HMAC_SECRET) {
                if (cbor_encode_hmac_secret_param("hmac-secret", dev, item,
                    ecdh, pk, &ext->hmac_salt) < 0) {
                        cbor_decref(&item);
                        return (NULL);
                }
        }
        if (ext->mask & FIDO_EXT_LARGEBLOB_KEY) {
                if (cbor_encode_largeblob_key_ext(item) < 0) {
                        cbor_decref(&item);
                        return (NULL);
                }
        }
        if (ext->mask & FIDO_EXT_PAYMENT) {
                if (cbor_add_bool(item, "thirdPartyPayment", FIDO_OPT_TRUE) < 0) {
                        cbor_decref(&item);
                        return (NULL);
                }
        }

        return (item);
}

int
cbor_decode_fmt(const cbor_item_t *item, char **fmt)
{
        char    *type = NULL;

        if (cbor_string_copy(item, &type) < 0) {
                fido_log_debug("%s: cbor_string_copy", __func__);
                return (-1);
        }

        if (strcmp(type, "packed") && strcmp(type, "fido-u2f") &&
            strcmp(type, "none") && strcmp(type, "tpm")) {
                fido_log_debug("%s: type=%s", __func__, type);
                free(type);
                return (-1);
        }

        *fmt = type;

        return (0);
}

struct cose_key {
        int kty;
        int alg;
        int crv;
};

static int
find_cose_alg(const cbor_item_t *key, const cbor_item_t *val, void *arg)
{
        struct cose_key *cose_key = arg;

        if (cbor_isa_uint(key) == true &&
            cbor_int_get_width(key) == CBOR_INT_8) {
                switch (cbor_get_uint8(key)) {
                case 1:
                        if (cbor_isa_uint(val) == false ||
                            cbor_get_int(val) > INT_MAX || cose_key->kty != 0) {
                                fido_log_debug("%s: kty", __func__);
                                return (-1);
                        }

                        cose_key->kty = (int)cbor_get_int(val);

                        break;
                case 3:
                        if (cbor_isa_negint(val) == false ||
                            cbor_get_int(val) > INT_MAX || cose_key->alg != 0) {
                                fido_log_debug("%s: alg", __func__);
                                return (-1);
                        }

                        cose_key->alg = -(int)cbor_get_int(val) - 1;

                        break;
                }
        } else if (cbor_isa_negint(key) == true &&
            cbor_int_get_width(key) == CBOR_INT_8) {
                if (cbor_get_uint8(key) == 0) {
                        /* get crv if not rsa, otherwise ignore */
                        if (cbor_isa_uint(val) == true &&
                            cbor_get_int(val) <= INT_MAX &&
                            cose_key->crv == 0)
                                cose_key->crv = (int)cbor_get_int(val);
                }
        }

        return (0);
}

static int
get_cose_alg(const cbor_item_t *item, int *cose_alg)
{
        struct cose_key cose_key;

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

        *cose_alg = 0;

        if (cbor_isa_map(item) == false ||
            cbor_map_is_definite(item) == false ||
            cbor_map_iter(item, &cose_key, find_cose_alg) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        switch (cose_key.alg) {
        case COSE_ES256:
                if (cose_key.kty != COSE_KTY_EC2 ||
                    cose_key.crv != COSE_P256) {
                        fido_log_debug("%s: invalid kty/crv", __func__);
                        return (-1);
                }
                break;
        case COSE_ES384:
                if (cose_key.kty != COSE_KTY_EC2 ||
                    cose_key.crv != COSE_P384) {
                        fido_log_debug("%s: invalid kty/crv", __func__);
                        return (-1);
                }
                break;
        case COSE_EDDSA:
                if (cose_key.kty != COSE_KTY_OKP ||
                    cose_key.crv != COSE_ED25519) {
                        fido_log_debug("%s: invalid kty/crv", __func__);
                        return (-1);
                }
                break;
        case COSE_RS256:
                if (cose_key.kty != COSE_KTY_RSA) {
                        fido_log_debug("%s: invalid kty/crv", __func__);
                        return (-1);
                }
                break;
        default:
                fido_log_debug("%s: unknown alg %d", __func__, cose_key.alg);

                return (-1);
        }

        *cose_alg = cose_key.alg;

        return (0);
}

int
cbor_decode_pubkey(const cbor_item_t *item, int *type, void *key)
{
        if (get_cose_alg(item, type) < 0) {
                fido_log_debug("%s: get_cose_alg", __func__);
                return (-1);
        }

        switch (*type) {
        case COSE_ES256:
                if (es256_pk_decode(item, key) < 0) {
                        fido_log_debug("%s: es256_pk_decode", __func__);
                        return (-1);
                }
                break;
        case COSE_ES384:
                if (es384_pk_decode(item, key) < 0) {
                        fido_log_debug("%s: es384_pk_decode", __func__);
                        return (-1);
                }
                break;
        case COSE_RS256:
                if (rs256_pk_decode(item, key) < 0) {
                        fido_log_debug("%s: rs256_pk_decode", __func__);
                        return (-1);
                }
                break;
        case COSE_EDDSA:
                if (eddsa_pk_decode(item, key) < 0) {
                        fido_log_debug("%s: eddsa_pk_decode", __func__);
                        return (-1);
                }
                break;
        default:
                fido_log_debug("%s: invalid cose_alg %d", __func__, *type);
                return (-1);
        }

        return (0);
}

static int
decode_attcred(const unsigned char **buf, size_t *len, int cose_alg,
    fido_attcred_t *attcred)
{
        cbor_item_t             *item = NULL;
        struct cbor_load_result  cbor;
        uint16_t                 id_len;
        int                      ok = -1;

        fido_log_xxd(*buf, *len, "%s", __func__);

        if (fido_buf_read(buf, len, &attcred->aaguid,
            sizeof(attcred->aaguid)) < 0) {
                fido_log_debug("%s: fido_buf_read aaguid", __func__);
                return (-1);
        }

        if (fido_buf_read(buf, len, &id_len, sizeof(id_len)) < 0) {
                fido_log_debug("%s: fido_buf_read id_len", __func__);
                return (-1);
        }

        attcred->id.len = (size_t)be16toh(id_len);
        if ((attcred->id.ptr = malloc(attcred->id.len)) == NULL)
                return (-1);

        fido_log_debug("%s: attcred->id.len=%zu", __func__, attcred->id.len);

        if (fido_buf_read(buf, len, attcred->id.ptr, attcred->id.len) < 0) {
                fido_log_debug("%s: fido_buf_read id", __func__);
                return (-1);
        }

        if ((item = cbor_load(*buf, *len, &cbor)) == NULL) {
                fido_log_debug("%s: cbor_load", __func__);
                goto fail;
        }

        if (cbor_decode_pubkey(item, &attcred->type, &attcred->pubkey) < 0) {
                fido_log_debug("%s: cbor_decode_pubkey", __func__);
                goto fail;
        }

        if (attcred->type != cose_alg) {
                fido_log_debug("%s: cose_alg mismatch (%d != %d)", __func__,
                    attcred->type, cose_alg);
                goto fail;
        }

        *buf += cbor.read;
        *len -= cbor.read;

        ok = 0;
fail:
        if (item != NULL)
                cbor_decref(&item);

        return (ok);
}

static int
decode_attobj(const cbor_item_t *key, const cbor_item_t *val, void *arg)
{
        fido_cred_t *cred = arg;
        char *name = NULL;
        int ok = -1;

        if (cbor_string_copy(key, &name) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                ok = 0; /* ignore */
                goto fail;
        }

        if (!strcmp(name, "fmt")) {
                if (cbor_decode_fmt(val, &cred->fmt) < 0) {
                        fido_log_debug("%s: cbor_decode_fmt", __func__);
                        goto fail;
                }
        } else if (!strcmp(name, "attStmt")) {
                if (cbor_decode_attstmt(val, &cred->attstmt) < 0) {
                        fido_log_debug("%s: cbor_decode_attstmt", __func__);
                        goto fail;
                }
        } else if (!strcmp(name, "authData")) {
                if (fido_blob_decode(val, &cred->authdata_raw) < 0) {
                        fido_log_debug("%s: fido_blob_decode", __func__);
                        goto fail;
                }
                if (cbor_decode_cred_authdata(val, cred->type,
                    &cred->authdata_cbor, &cred->authdata, &cred->attcred,
                    &cred->authdata_ext) < 0) {
                        fido_log_debug("%s: cbor_decode_cred_authdata",
                            __func__);
                        goto fail;
                }
        }

        ok = 0;
fail:
        free(name);

        return (ok);
}

/* XXX introduce fido_attobj_t? */
int
cbor_decode_attobj(const cbor_item_t *item, fido_cred_t *cred)
{
        if (cbor_isa_map(item) == false ||
            cbor_map_is_definite(item) == false ||
            cbor_map_iter(item, cred, decode_attobj) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        return (0);
}

static int
decode_cred_extension(const cbor_item_t *key, const cbor_item_t *val, void *arg)
{
        fido_cred_extout_t      *ext = arg;
        char                    *type = NULL;
        int                      ok = -1;

        if (cbor_string_copy(key, &type) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                ok = 0; /* ignore */
                goto out;
        }

        if (strcmp(type, "hmac-secret") == 0) {
                if (cbor_decode_bool(val, NULL) < 0) {
                        fido_log_debug("%s: cbor_decode_bool", __func__);
                        goto out;
                }
                if (cbor_ctrl_value(val) == CBOR_CTRL_TRUE)
                        ext->attr.mask |= FIDO_EXT_HMAC_SECRET;
        } else if (strcmp(type, "hmac-secret-mc") == 0) {
                if (fido_blob_decode(val, &ext->hmac_secret_enc) < 0) {
                        fido_log_debug("%s: fido_blob_decode", __func__);
                        goto out;
                }
                ext->attr.mask |= FIDO_EXT_HMAC_SECRET_MC;
        } else if (strcmp(type, "credProtect") == 0) {
                if (cbor_isa_uint(val) == false ||
                    cbor_int_get_width(val) != CBOR_INT_8) {
                        fido_log_debug("%s: cbor type", __func__);
                        goto out;
                }
                ext->attr.mask |= FIDO_EXT_CRED_PROTECT;
                ext->attr.prot = cbor_get_uint8(val);
        } else if (strcmp(type, "credBlob") == 0) {
                if (cbor_decode_bool(val, NULL) < 0) {
                        fido_log_debug("%s: cbor_decode_bool", __func__);
                        goto out;
                }
                if (cbor_ctrl_value(val) == CBOR_CTRL_TRUE)
                        ext->attr.mask |= FIDO_EXT_CRED_BLOB;
        } else if (strcmp(type, "minPinLength") == 0) {
                if (cbor_isa_uint(val) == false ||
                    cbor_int_get_width(val) != CBOR_INT_8) {
                        fido_log_debug("%s: cbor type", __func__);
                        goto out;
                }
                ext->attr.mask |= FIDO_EXT_MINPINLEN;
                ext->attr.minpinlen = cbor_get_uint8(val);
        }

        ok = 0;
out:
        free(type);

        return (ok);
}

static int
decode_cred_extensions(const unsigned char **buf, size_t *len,
    fido_cred_extout_t *authdata_ext)
{
        cbor_item_t             *item = NULL;
        struct cbor_load_result  cbor;
        int                      ok = -1;

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

        fido_log_xxd(*buf, *len, "%s", __func__);

        if ((item = cbor_load(*buf, *len, &cbor)) == NULL) {
                fido_log_debug("%s: cbor_load", __func__);
                goto fail;
        }

        if (cbor_isa_map(item) == false ||
            cbor_map_is_definite(item) == false ||
            cbor_map_iter(item, authdata_ext, decode_cred_extension) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                goto fail;
        }

        *buf += cbor.read;
        *len -= cbor.read;

        ok = 0;
fail:
        if (item != NULL)
                cbor_decref(&item);

        return (ok);
}

static int
decode_assert_extension(const cbor_item_t *key, const cbor_item_t *val,
    void *arg)
{
        fido_assert_extattr_t   *authdata_ext = arg;
        char                    *type = NULL;
        int                      ok = -1;

        if (cbor_string_copy(key, &type) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                ok = 0; /* ignore */
                goto out;
        }

        if (strcmp(type, "hmac-secret") == 0) {
                if (fido_blob_decode(val, &authdata_ext->hmac_secret_enc) < 0) {
                        fido_log_debug("%s: fido_blob_decode", __func__);
                        goto out;
                }
                authdata_ext->mask |= FIDO_EXT_HMAC_SECRET;
        } else if (strcmp(type, "credBlob") == 0) {
                if (fido_blob_decode(val, &authdata_ext->blob) < 0) {
                        fido_log_debug("%s: fido_blob_decode", __func__);
                        goto out;
                }
                authdata_ext->mask |= FIDO_EXT_CRED_BLOB;
        } else if (strcmp(type, "thirdPartyPayment") == 0) {
                if (cbor_decode_bool(val, NULL) < 0) {
                        fido_log_debug("%s: cbor_decode_bool", __func__);
                        goto out;
                }
                if (cbor_ctrl_value(val) == CBOR_CTRL_TRUE)
                        authdata_ext->mask |= FIDO_EXT_PAYMENT;
        }

        ok = 0;
out:
        free(type);

        return (ok);
}

static int
decode_assert_extensions(const unsigned char **buf, size_t *len,
    fido_assert_extattr_t *authdata_ext)
{
        cbor_item_t             *item = NULL;
        struct cbor_load_result  cbor;
        int                      ok = -1;

        fido_log_xxd(*buf, *len, "%s", __func__);

        if ((item = cbor_load(*buf, *len, &cbor)) == NULL) {
                fido_log_debug("%s: cbor_load", __func__);
                goto fail;
        }

        if (cbor_isa_map(item) == false ||
            cbor_map_is_definite(item) == false ||
            cbor_map_iter(item, authdata_ext, decode_assert_extension) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                goto fail;
        }

        *buf += cbor.read;
        *len -= cbor.read;

        ok = 0;
fail:
        if (item != NULL)
                cbor_decref(&item);

        return (ok);
}

int
cbor_decode_cred_authdata(const cbor_item_t *item, int cose_alg,
    fido_blob_t *authdata_cbor, fido_authdata_t *authdata,
    fido_attcred_t *attcred, fido_cred_extout_t *authdata_ext)
{
        const unsigned char     *buf = NULL;
        size_t                   len;
        size_t                   alloc_len;

        if (cbor_isa_bytestring(item) == false ||
            cbor_bytestring_is_definite(item) == false) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        if (authdata_cbor->ptr != NULL ||
            (authdata_cbor->len = cbor_serialize_alloc(item,
            &authdata_cbor->ptr, &alloc_len)) == 0) {
                fido_log_debug("%s: cbor_serialize_alloc", __func__);
                return (-1);
        }

        buf = cbor_bytestring_handle(item);
        len = cbor_bytestring_length(item);
        fido_log_xxd(buf, len, "%s", __func__);

        if (fido_buf_read(&buf, &len, authdata, sizeof(*authdata)) < 0) {
                fido_log_debug("%s: fido_buf_read", __func__);
                return (-1);
        }

        authdata->sigcount = be32toh(authdata->sigcount);

        if (attcred != NULL) {
                if ((authdata->flags & CTAP_AUTHDATA_ATT_CRED) == 0 ||
                    decode_attcred(&buf, &len, cose_alg, attcred) < 0)
                        return (-1);
        }

        if (authdata_ext != NULL) {
                if ((authdata->flags & CTAP_AUTHDATA_EXT_DATA) != 0 &&
                    decode_cred_extensions(&buf, &len, authdata_ext) < 0)
                        return (-1);
        }

        /* XXX we should probably ensure that len == 0 at this point */

        return (FIDO_OK);
}

int
cbor_decode_assert_authdata(const cbor_item_t *item, fido_blob_t *authdata_cbor,
    fido_authdata_t *authdata, fido_assert_extattr_t *authdata_ext)
{
        const unsigned char     *buf = NULL;
        size_t                   len;
        size_t                   alloc_len;

        if (cbor_isa_bytestring(item) == false ||
            cbor_bytestring_is_definite(item) == false) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        if (authdata_cbor->ptr != NULL ||
            (authdata_cbor->len = cbor_serialize_alloc(item,
            &authdata_cbor->ptr, &alloc_len)) == 0) {
                fido_log_debug("%s: cbor_serialize_alloc", __func__);
                return (-1);
        }

        buf = cbor_bytestring_handle(item);
        len = cbor_bytestring_length(item);

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

        if (fido_buf_read(&buf, &len, authdata, sizeof(*authdata)) < 0) {
                fido_log_debug("%s: fido_buf_read", __func__);
                return (-1);
        }

        authdata->sigcount = be32toh(authdata->sigcount);

        if ((authdata->flags & CTAP_AUTHDATA_EXT_DATA) != 0) {
                if (decode_assert_extensions(&buf, &len, authdata_ext) < 0) {
                        fido_log_debug("%s: decode_assert_extensions",
                            __func__);
                        return (-1);
                }
        }

        /* XXX we should probably ensure that len == 0 at this point */

        return (FIDO_OK);
}

static int
decode_x5c(const cbor_item_t *item, void *arg)
{
        fido_blob_array_t *x5c = arg;
        fido_blob_t *list_ptr = NULL;
        fido_blob_t x5c_blob;

        memset(&x5c_blob, 0, sizeof(x5c_blob));

        if (fido_blob_decode(item, &x5c_blob) < 0) {
                fido_log_debug("%s: fido_blob_decode", __func__);
                return (-1);
        }

        if (x5c->len == SIZE_MAX) {
                fido_blob_reset(&x5c_blob);
                return (-1);
        }

        if ((list_ptr = recallocarray(x5c->ptr, x5c->len,
            x5c->len + 1, sizeof(x5c_blob))) == NULL) {
                fido_blob_reset(&x5c_blob);
                return (-1);
        }

        list_ptr[x5c->len++] = x5c_blob;
        x5c->ptr = list_ptr;

        return (0);
}

static int
decode_x5c_array(const cbor_item_t *item, fido_blob_array_t *arr)
{
        if (arr->len) {
                fido_log_debug("%s: dup", __func__);
                return (-1);
        }
        if (cbor_isa_array(item) == false ||
            cbor_array_is_definite(item) == false) {
                fido_log_debug("%s: cbor", __func__);
                return (-1);
        }
        return (cbor_array_iter(item, arr, decode_x5c));
}

static int
decode_attstmt_entry(const cbor_item_t *key, const cbor_item_t *val, void *arg)
{
        fido_attstmt_t  *attstmt = arg;
        char            *name = NULL;
        int              ok = -1;

        if (cbor_string_copy(key, &name) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                ok = 0; /* ignore */
                goto out;
        }

        if (!strcmp(name, "alg")) {
                if (cbor_isa_negint(val) == false ||
                    cbor_get_int(val) > UINT16_MAX) {
                        fido_log_debug("%s: alg", __func__);
                        goto out;
                }
                attstmt->alg = -(int)cbor_get_int(val) - 1;
                if (attstmt->alg != COSE_ES256 && attstmt->alg != COSE_ES384 &&
                    attstmt->alg != COSE_RS256 && attstmt->alg != COSE_EDDSA &&
                    attstmt->alg != COSE_RS1) {
                        fido_log_debug("%s: unsupported attstmt->alg=%d",
                            __func__, attstmt->alg);
                        goto out;
                }
        } else if (!strcmp(name, "sig")) {
                if (fido_blob_decode(val, &attstmt->sig) < 0) {
                        fido_log_debug("%s: sig", __func__);
                        goto out;
                }
        } else if (!strcmp(name, "x5c")) {
                if (decode_x5c_array(val, &attstmt->x5c)) {
                        fido_log_debug("%s: x5c", __func__);
                        goto out;
                }
        } else if (!strcmp(name, "certInfo")) {
                if (fido_blob_decode(val, &attstmt->certinfo) < 0) {
                        fido_log_debug("%s: certinfo", __func__);
                        goto out;
                }
        } else if (!strcmp(name, "pubArea")) {
                if (fido_blob_decode(val, &attstmt->pubarea) < 0) {
                        fido_log_debug("%s: pubarea", __func__);
                        goto out;
                }
        }

        ok = 0;
out:
        free(name);

        return (ok);
}

int
cbor_decode_attstmt(const cbor_item_t *item, fido_attstmt_t *attstmt)
{
        size_t alloc_len;

        if (cbor_isa_map(item) == false ||
            cbor_map_is_definite(item) == false ||
            cbor_map_iter(item, attstmt, decode_attstmt_entry) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        if (attstmt->cbor.ptr != NULL ||
            (attstmt->cbor.len = cbor_serialize_alloc(item,
            &attstmt->cbor.ptr, &alloc_len)) == 0) {
                fido_log_debug("%s: cbor_serialize_alloc", __func__);
                return (-1);
        }

        return (0);
}

int
cbor_decode_uint64(const cbor_item_t *item, uint64_t *n)
{
        if (cbor_isa_uint(item) == false) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        *n = cbor_get_int(item);

        return (0);
}

static int
decode_cred_id_entry(const cbor_item_t *key, const cbor_item_t *val, void *arg)
{
        fido_blob_t     *id = arg;
        char            *name = NULL;
        int              ok = -1;

        if (cbor_string_copy(key, &name) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                ok = 0; /* ignore */
                goto out;
        }

        if (!strcmp(name, "id"))
                if (fido_blob_decode(val, id) < 0) {
                        fido_log_debug("%s: cbor_bytestring_copy", __func__);
                        goto out;
                }

        ok = 0;
out:
        free(name);

        return (ok);
}

int
cbor_decode_cred_id(const cbor_item_t *item, fido_blob_t *id)
{
        if (cbor_isa_map(item) == false ||
            cbor_map_is_definite(item) == false ||
            cbor_map_iter(item, id, decode_cred_id_entry) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        return (0);
}

static int
decode_user_entry(const cbor_item_t *key, const cbor_item_t *val, void *arg)
{
        fido_user_t     *user = arg;
        char            *name = NULL;
        int              ok = -1;

        if (cbor_string_copy(key, &name) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                ok = 0; /* ignore */
                goto out;
        }

        if (!strcmp(name, "icon")) {
                if (cbor_string_copy(val, &user->icon) < 0) {
                        fido_log_debug("%s: icon", __func__);
                        goto out;
                }
        } else if (!strcmp(name, "name")) {
                if (cbor_string_copy(val, &user->name) < 0) {
                        fido_log_debug("%s: name", __func__);
                        goto out;
                }
        } else if (!strcmp(name, "displayName")) {
                if (cbor_string_copy(val, &user->display_name) < 0) {
                        fido_log_debug("%s: display_name", __func__);
                        goto out;
                }
        } else if (!strcmp(name, "id")) {
                if (fido_blob_decode(val, &user->id) < 0) {
                        fido_log_debug("%s: id", __func__);
                        goto out;
                }
        }

        ok = 0;
out:
        free(name);

        return (ok);
}

int
cbor_decode_user(const cbor_item_t *item, fido_user_t *user)
{
        if (cbor_isa_map(item) == false ||
            cbor_map_is_definite(item) == false ||
            cbor_map_iter(item, user, decode_user_entry) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        return (0);
}

static int
decode_rp_entity_entry(const cbor_item_t *key, const cbor_item_t *val,
    void *arg)
{
        fido_rp_t       *rp = arg;
        char            *name = NULL;
        int              ok = -1;

        if (cbor_string_copy(key, &name) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                ok = 0; /* ignore */
                goto out;
        }

        if (!strcmp(name, "id")) {
                if (cbor_string_copy(val, &rp->id) < 0) {
                        fido_log_debug("%s: id", __func__);
                        goto out;
                }
        } else if (!strcmp(name, "name")) {
                if (cbor_string_copy(val, &rp->name) < 0) {
                        fido_log_debug("%s: name", __func__);
                        goto out;
                }
        }

        ok = 0;
out:
        free(name);

        return (ok);
}

int
cbor_decode_rp_entity(const cbor_item_t *item, fido_rp_t *rp)
{
        if (cbor_isa_map(item) == false ||
            cbor_map_is_definite(item) == false ||
            cbor_map_iter(item, rp, decode_rp_entity_entry) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        return (0);
}

int
cbor_decode_bool(const cbor_item_t *item, bool *v)
{
        if (cbor_isa_float_ctrl(item) == false ||
            cbor_float_get_width(item) != CBOR_FLOAT_0 ||
            cbor_is_bool(item) == false) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        if (v != NULL)
                *v = cbor_ctrl_value(item) == CBOR_CTRL_TRUE;

        return (0);
}

cbor_item_t *
cbor_build_uint(const uint64_t value)
{
        if (value <= UINT8_MAX)
                return cbor_build_uint8((uint8_t)value);
        else if (value <= UINT16_MAX)
                return cbor_build_uint16((uint16_t)value);
        else if (value <= UINT32_MAX)
                return cbor_build_uint32((uint32_t)value);

        return cbor_build_uint64(value);
}

int
cbor_array_append(cbor_item_t **array, cbor_item_t *item)
{
        cbor_item_t **v, *ret;
        size_t n;

        if ((v = cbor_array_handle(*array)) == NULL ||
            (n = cbor_array_size(*array)) == SIZE_MAX ||
            (ret = cbor_new_definite_array(n + 1)) == NULL)
                return -1;
        for (size_t i = 0; i < n; i++) {
                if (cbor_array_push(ret, v[i]) == 0) {
                        cbor_decref(&ret);
                        return -1;
                }
        }
        if (cbor_array_push(ret, item) == 0) {
                cbor_decref(&ret);
                return -1;
        }
        cbor_decref(array);
        *array = ret;

        return 0;
}

int
cbor_array_drop(cbor_item_t **array, size_t idx)
{
        cbor_item_t **v, *ret;
        size_t n;

        if ((v = cbor_array_handle(*array)) == NULL ||
            (n = cbor_array_size(*array)) == 0 || idx >= n ||
            (ret = cbor_new_definite_array(n - 1)) == NULL)
                return -1;
        for (size_t i = 0; i < n; i++) {
                if (i != idx && cbor_array_push(ret, v[i]) == 0) {
                        cbor_decref(&ret);
                        return -1;
                }
        }
        cbor_decref(array);
        *array = ret;

        return 0;
}

Coverage Report

Created: 2026-04-08 06:32