/libfido2/src/info.c

Source
/*
 * Copyright (c) 2018-2026 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 "fido.h"

static int
decode_string(const cbor_item_t *item, void *arg)
{
        fido_str_array_t        *a = arg;
        const size_t             i = a->len;

        /* keep ptr[x] and len consistent */
        if (cbor_string_copy(item, &a->ptr[i]) < 0) {
                fido_log_debug("%s: cbor_string_copy", __func__);
                return (-1);
        }

        a->len++;

        return (0);
}

static int
decode_string_array(const cbor_item_t *item, fido_str_array_t *v)
{
        v->ptr = NULL;
        v->len = 0;

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

        v->ptr = calloc(cbor_array_size(item), sizeof(char *));
        if (v->ptr == NULL)
                return (-1);

        if (cbor_array_iter(item, v, decode_string) < 0) {
                fido_log_debug("%s: decode_string", __func__);
                return (-1);
        }

        return (0);
}

static int
decode_aaguid(const cbor_item_t *item, unsigned char *aaguid, size_t aaguid_len)
{
        if (cbor_isa_bytestring(item) == false ||
            cbor_bytestring_is_definite(item) == false ||
            cbor_bytestring_length(item) != aaguid_len) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        memcpy(aaguid, cbor_bytestring_handle(item), aaguid_len);

        return (0);
}

static int
decode_option(const cbor_item_t *key, const cbor_item_t *val, void *arg)
{
        fido_opt_array_t        *o = arg;
        const size_t             i = o->len;

        if (cbor_decode_bool(val, NULL) < 0) {
                fido_log_debug("%s: cbor_decode_bool", __func__);
                return (0); /* ignore */
        }

        if (cbor_string_copy(key, &o->name[i]) < 0) {
                fido_log_debug("%s: cbor_string_copy", __func__);
                return (0); /* ignore */
        }

        /* keep name/value and len consistent */
        o->value[i] = cbor_ctrl_value(val) == CBOR_CTRL_TRUE;
        o->len++;

        return (0);
}

static int
decode_options(const cbor_item_t *item, fido_opt_array_t *o)
{
        o->name = NULL;
        o->value = NULL;
        o->len = 0;

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

        o->name = calloc(cbor_map_size(item), sizeof(char *));
        o->value = calloc(cbor_map_size(item), sizeof(bool));
        if (o->name == NULL || o->value == NULL)
                return (-1);

        return (cbor_map_iter(item, o, decode_option));
}

static int
decode_byte_array_item(const cbor_item_t *item, void *arg)
{
        fido_byte_array_t       *p = arg;
        const size_t             i = p->len;

        if (cbor_isa_uint(item) == false ||
            cbor_int_get_width(item) != CBOR_INT_8) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        /* keep ptr[x] and len consistent */
        p->ptr[i] = cbor_get_uint8(item);
        p->len++;

        return (0);
}

static int
decode_byte_array(const cbor_item_t *item, fido_byte_array_t *p)
{
        p->ptr = NULL;
        p->len = 0;

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

        p->ptr = calloc(cbor_array_size(item), sizeof(uint8_t));
        if (p->ptr == NULL)
                return (-1);

        if (cbor_array_iter(item, p, decode_byte_array_item) < 0) {
                fido_log_debug("%s: decode_byte_array_item", __func__);
                return (-1);
        }

        return (0);
}

static int
decode_algorithm_entry(const cbor_item_t *key, const cbor_item_t *val,
    void *arg)
{
        fido_algo_t *alg = 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) > INT_MAX || alg->cose != 0) {
                        fido_log_debug("%s: alg", __func__);
                        goto out;
                }
                alg->cose = -(int)cbor_get_int(val) - 1;
        } else if (!strcmp(name, "type")) {
                if (cbor_string_copy(val, &alg->type) < 0) {
                        fido_log_debug("%s: type", __func__);
                        goto out;
                }
        }

        ok = 0;
out:
        free(name);

        return (ok);
}

static int
decode_algorithm(const cbor_item_t *item, void *arg)
{
        fido_algo_array_t *aa = arg;
        const size_t i = aa->len;

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

        memset(&aa->ptr[i], 0, sizeof(aa->ptr[i]));

        if (cbor_map_iter(item, &aa->ptr[i], decode_algorithm_entry) < 0) {
                fido_log_debug("%s: decode_algorithm_entry", __func__);
                fido_algo_free(&aa->ptr[i]);
                return (-1);
        }

        /* keep ptr[x] and len consistent */
        aa->len++;

        return (0);
}

static int
decode_algorithms(const cbor_item_t *item, fido_algo_array_t *aa)
{
        aa->ptr = NULL;
        aa->len = 0;

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

        aa->ptr = calloc(cbor_array_size(item), sizeof(fido_algo_t));
        if (aa->ptr == NULL)
                return (-1);

        if (cbor_array_iter(item, aa, decode_algorithm) < 0) {
                fido_log_debug("%s: decode_algorithm", __func__);
                return (-1);
        }

        return (0);
}

static int
decode_cert(const cbor_item_t *key, const cbor_item_t *val, void *arg)
{
        fido_cert_array_t       *c = arg;
        const size_t             i = c->len;

        if (cbor_is_int(val) == false) {
                fido_log_debug("%s: cbor_is_int", __func__);
                return (0); /* ignore */
        }

        if (cbor_string_copy(key, &c->name[i]) < 0) {
                fido_log_debug("%s: cbor_string_copy", __func__);
                return (0); /* ignore */
        }

        /* keep name/value and len consistent */
        c->value[i] = cbor_get_int(val);
        c->len++;

        return (0);
}

static int
decode_certs(const cbor_item_t *item, fido_cert_array_t *c)
{
        c->name = NULL;
        c->value = NULL;
        c->len = 0;

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

        c->name = calloc(cbor_map_size(item), sizeof(char *));
        c->value = calloc(cbor_map_size(item), sizeof(uint64_t));
        if (c->name == NULL || c->value == NULL)
                return (-1);

        return (cbor_map_iter(item, c, decode_cert));
}

static int
parse_reply_element(const cbor_item_t *key, const cbor_item_t *val, void *arg)
{
        fido_cbor_info_t *ci = arg;
        uint64_t x;
        bool b;

        if (cbor_isa_uint(key) == false ||
            cbor_int_get_width(key) != CBOR_INT_8) {
                fido_log_debug("%s: cbor type", __func__);
                return (0); /* ignore */
        }

        switch (cbor_get_uint8(key)) {
        case 1: /* versions */
                return (decode_string_array(val, &ci->versions));
        case 2: /* extensions */
                return (decode_string_array(val, &ci->extensions));
        case 3: /* aaguid */
                return (decode_aaguid(val, ci->aaguid, sizeof(ci->aaguid)));
        case 4: /* options */
                return (decode_options(val, &ci->options));
        case 5: /* maxMsgSize */
                return (cbor_decode_uint64(val, &ci->maxmsgsiz));
        case 6: /* pinProtocols */
                return (decode_byte_array(val, &ci->protocols));
        case 7: /* maxCredentialCountInList */
                return (cbor_decode_uint64(val, &ci->maxcredcntlst));
        case 8: /* maxCredentialIdLength */
                return (cbor_decode_uint64(val, &ci->maxcredidlen));
        case 9: /* transports */
                return (decode_string_array(val, &ci->transports));
        case 10: /* algorithms */
                return (decode_algorithms(val, &ci->algorithms));
        case 11: /* maxSerializedLargeBlobArray */
                return (cbor_decode_uint64(val, &ci->maxlargeblob));
        case 12: /* forcePINChange */
                return (cbor_decode_bool(val, &ci->new_pin_reqd));
        case 13: /* minPINLength */
                return (cbor_decode_uint64(val, &ci->minpinlen));
        case 14: /* fwVersion */
                return (cbor_decode_uint64(val, &ci->fwversion));
        case 15: /* maxCredBlobLen */
                return (cbor_decode_uint64(val, &ci->maxcredbloblen));
        case 16: /* maxRPIDsForSetMinPINLength */
                return (cbor_decode_uint64(val, &ci->maxrpid_minlen));
        case 17: /* preferredPlatformUvAttempts */
                return (cbor_decode_uint64(val, &ci->uv_attempts));
        case 18: /* uvModality */
                return (cbor_decode_uint64(val, &ci->uv_modality));
        case 19: /* certifications */
                return (decode_certs(val, &ci->certs));
        case 20: /* remainingDiscoverableCredentials */
                if (cbor_decode_uint64(val, &x) < 0 || x > INT64_MAX) {
                        fido_log_debug("%s: cbor_decode_uint64", __func__);
                        return (-1);
                }
                ci->rk_remaining = (int64_t)x;
                return (0);
        case 22: /* attestationFormats */
                return (decode_string_array(val, &ci->attfmts));
        case 23: /* uvCountSinceLastPinEntry */
                if (cbor_decode_uint64(val, &x) < 0 || x > INT64_MAX) {
                        fido_log_debug("%s: cbor_decode_uint64", __func__);
                        return (-1);
                }
                ci->uv_since_pin = (int64_t)x;
                return (0);
        case 24: /* longTouchForReset */
                return (cbor_decode_bool(val, &ci->long_reset));
        case 25: /* encIdentifier */
                return (fido_blob_decode(val, &ci->encid));
        case 26: /* transportsForReset */
                return (decode_string_array(val, &ci->rsttransports));
        case 27: /* pinComplexityPolicy */
                if (cbor_decode_bool(val, &b) < 0) {
                        fido_log_debug("%s: cbor_decode_bool", __func__);
                        return (-1);
                }
                ci->pinpolicy = b;
                return (0);
        case 28: /* pinComplexityPolicyUrl */
                return (fido_blob_decode(val, &ci->pinpolicyurl));
        case 29: /* maxPINLength */
                return (cbor_decode_uint64(val, &ci->maxpinlen));
        case 30: /* encCredStoreState */
                return (fido_blob_decode(val, &ci->encstate));
        case 31: /* authenticatorConfigCommands */
                return (decode_byte_array(val, &ci->cfgcmds));
        default: /* ignore */
                fido_log_debug("%s: cbor type: 0x%02x", __func__, cbor_get_uint8(key));
                return (0);
        }
}

static int
fido_dev_get_cbor_info_tx(fido_dev_t *dev, int *ms)
{
        const unsigned char cbor[] = { CTAP_CBOR_GETINFO };

        fido_log_debug("%s: dev=%p", __func__, (void *)dev);

        if (fido_tx(dev, CTAP_CMD_CBOR, cbor, sizeof(cbor), ms) < 0) {
                fido_log_debug("%s: fido_tx", __func__);
                return (FIDO_ERR_TX);
        }

        return (FIDO_OK);
}

static int
fido_dev_get_cbor_info_rx(fido_dev_t *dev, fido_cbor_info_t *ci, int *ms)
{
        unsigned char   *msg;
        int              msglen;
        int              r;

        fido_log_debug("%s: dev=%p, ci=%p, ms=%d", __func__, (void *)dev,
            (void *)ci, *ms);

        fido_cbor_info_reset(ci);

        if ((msg = malloc(FIDO_MAXMSG)) == NULL) {
                r = FIDO_ERR_INTERNAL;
                goto out;
        }

        if ((msglen = fido_rx(dev, CTAP_CMD_CBOR, msg, FIDO_MAXMSG, ms)) < 0) {
                fido_log_debug("%s: fido_rx", __func__);
                r = FIDO_ERR_RX;
                goto out;
        }

        r = cbor_parse_reply(msg, (size_t)msglen, ci, parse_reply_element);
out:
        freezero(msg, FIDO_MAXMSG);

        return (r);
}

int
fido_dev_get_cbor_info_wait(fido_dev_t *dev, fido_cbor_info_t *ci, int *ms)
{
        int r;

#ifdef USE_WINHELLO
        if (dev->flags & FIDO_DEV_WINHELLO)
                return (fido_winhello_get_cbor_info(dev, ci));
#endif
        if ((r = fido_dev_get_cbor_info_tx(dev, ms)) != FIDO_OK ||
            (r = fido_dev_get_cbor_info_rx(dev, ci, ms)) != FIDO_OK)
                return (r);

        return (FIDO_OK);
}

int
fido_dev_get_cbor_info(fido_dev_t *dev, fido_cbor_info_t *ci)
{
        int ms = dev->timeout_ms;

        return (fido_dev_get_cbor_info_wait(dev, ci, &ms));
}

/*
 * get/set functions for fido_cbor_info_t; always at the end of the file
 */

fido_cbor_info_t *
fido_cbor_info_new(void)
{
        fido_cbor_info_t *ci;

        if ((ci = calloc(1, sizeof(fido_cbor_info_t))) == NULL)
                return (NULL);

        fido_cbor_info_reset(ci);

        return (ci);
}

void
fido_cbor_info_reset(fido_cbor_info_t *ci)
{
        fido_str_array_free(&ci->versions);
        fido_str_array_free(&ci->extensions);
        fido_str_array_free(&ci->transports);
        fido_str_array_free(&ci->attfmts);
        fido_str_array_free(&ci->rsttransports);
        fido_opt_array_free(&ci->options);
        fido_byte_array_free(&ci->protocols);
        fido_byte_array_free(&ci->cfgcmds);
        fido_algo_array_free(&ci->algorithms);
        fido_cert_array_free(&ci->certs);
        fido_blob_reset(&ci->encid);
        fido_blob_reset(&ci->id);
        fido_blob_reset(&ci->pinpolicyurl);
        fido_blob_reset(&ci->encstate);
        fido_blob_reset(&ci->state);
        ci->rk_remaining = -1;
        ci->uv_since_pin = -1;
        ci->pinpolicy = -1;
}

void
fido_cbor_info_free(fido_cbor_info_t **ci_p)
{
        fido_cbor_info_t *ci;

        if (ci_p == NULL || (ci = *ci_p) ==  NULL)
                return;
        fido_cbor_info_reset(ci);
        free(ci);
        *ci_p = NULL;
}

char **
fido_cbor_info_versions_ptr(const fido_cbor_info_t *ci)
{
        return (ci->versions.ptr);
}

size_t
fido_cbor_info_versions_len(const fido_cbor_info_t *ci)
{
        return (ci->versions.len);
}

char **
fido_cbor_info_extensions_ptr(const fido_cbor_info_t *ci)
{
        return (ci->extensions.ptr);
}

size_t
fido_cbor_info_extensions_len(const fido_cbor_info_t *ci)
{
        return (ci->extensions.len);
}

char **
fido_cbor_info_transports_ptr(const fido_cbor_info_t *ci)
{
        return (ci->transports.ptr);
}

size_t
fido_cbor_info_transports_len(const fido_cbor_info_t *ci)
{
        return (ci->transports.len);
}

const unsigned char *
fido_cbor_info_aaguid_ptr(const fido_cbor_info_t *ci)
{
        return (ci->aaguid);
}

size_t
fido_cbor_info_aaguid_len(const fido_cbor_info_t *ci)
{
        return (sizeof(ci->aaguid));
}

const unsigned char *
fido_cbor_info_encid_ptr(const fido_cbor_info_t *ci)
{
        return (ci->encid.ptr);
}

size_t
fido_cbor_info_encid_len(const fido_cbor_info_t *ci)
{
        return (ci->encid.len);
}

const unsigned char *
fido_cbor_info_id_ptr(const fido_cbor_info_t *ci)
{
        return (ci->id.ptr);
}

size_t
fido_cbor_info_id_len(const fido_cbor_info_t *ci)
{
        return (ci->id.len);
}

const unsigned char *
fido_cbor_info_encstate_ptr(const fido_cbor_info_t *ci)
{
        return (ci->encstate.ptr);
}

size_t
fido_cbor_info_encstate_len(const fido_cbor_info_t *ci)
{
        return (ci->encstate.len);
}

const unsigned char *
fido_cbor_info_state_ptr(const fido_cbor_info_t *ci)
{
        return (ci->state.ptr);
}

size_t
fido_cbor_info_state_len(const fido_cbor_info_t *ci)
{
        return (ci->state.len);
}

char **
fido_cbor_info_options_name_ptr(const fido_cbor_info_t *ci)
{
        return (ci->options.name);
}

const bool *
fido_cbor_info_options_value_ptr(const fido_cbor_info_t *ci)
{
        return (ci->options.value);
}

size_t
fido_cbor_info_options_len(const fido_cbor_info_t *ci)
{
        return (ci->options.len);
}

uint64_t
fido_cbor_info_maxcredbloblen(const fido_cbor_info_t *ci)
{
        return (ci->maxcredbloblen);
}

uint64_t
fido_cbor_info_maxmsgsiz(const fido_cbor_info_t *ci)
{
        return (ci->maxmsgsiz);
}

uint64_t
fido_cbor_info_maxcredcntlst(const fido_cbor_info_t *ci)
{
        return (ci->maxcredcntlst);
}

uint64_t
fido_cbor_info_maxcredidlen(const fido_cbor_info_t *ci)
{
        return (ci->maxcredidlen);
}

uint64_t
fido_cbor_info_maxlargeblob(const fido_cbor_info_t *ci)
{
        return (ci->maxlargeblob);
}

uint64_t
fido_cbor_info_fwversion(const fido_cbor_info_t *ci)
{
        return (ci->fwversion);
}

uint64_t
fido_cbor_info_minpinlen(const fido_cbor_info_t *ci)
{
        return (ci->minpinlen);
}

uint64_t
fido_cbor_info_maxrpid_minpinlen(const fido_cbor_info_t *ci)
{
        return (ci->maxrpid_minlen);
}

uint64_t
fido_cbor_info_uv_attempts(const fido_cbor_info_t *ci)
{
        return (ci->uv_attempts);
}

int64_t
fido_cbor_info_uv_count_since_pin(const fido_cbor_info_t *ci)
{
        return (ci->uv_since_pin);
}

uint64_t
fido_cbor_info_uv_modality(const fido_cbor_info_t *ci)
{
        return (ci->uv_modality);
}

int64_t
fido_cbor_info_rk_remaining(const fido_cbor_info_t *ci)
{
        return (ci->rk_remaining);
}

const uint8_t *
fido_cbor_info_protocols_ptr(const fido_cbor_info_t *ci)
{
        return (ci->protocols.ptr);
}

size_t
fido_cbor_info_protocols_len(const fido_cbor_info_t *ci)
{
        return (ci->protocols.len);
}

size_t
fido_cbor_info_algorithm_count(const fido_cbor_info_t *ci)
{
        return (ci->algorithms.len);
}

const char *
fido_cbor_info_algorithm_type(const fido_cbor_info_t *ci, size_t idx)
{
        if (idx >= ci->algorithms.len)
                return (NULL);

        return (ci->algorithms.ptr[idx].type);
}

int
fido_cbor_info_algorithm_cose(const fido_cbor_info_t *ci, size_t idx)
{
        if (idx >= ci->algorithms.len)
                return (0);

        return (ci->algorithms.ptr[idx].cose);
}

bool
fido_cbor_info_new_pin_required(const fido_cbor_info_t *ci)
{
        return (ci->new_pin_reqd);
}

bool
fido_cbor_info_long_touch_reset(const fido_cbor_info_t *ci)
{
        return (ci->long_reset);
}

char **
fido_cbor_info_certs_name_ptr(const fido_cbor_info_t *ci)
{
        return (ci->certs.name);
}

const uint64_t *
fido_cbor_info_certs_value_ptr(const fido_cbor_info_t *ci)
{
        return (ci->certs.value);
}

size_t
fido_cbor_info_certs_len(const fido_cbor_info_t *ci)
{
        return (ci->certs.len);
}

char **
fido_cbor_info_attfmts_ptr(const fido_cbor_info_t *ci)
{
        return (ci->attfmts.ptr);
}

size_t
fido_cbor_info_attfmts_len(const fido_cbor_info_t *ci)
{
        return (ci->attfmts.len);
}

char **
fido_cbor_info_reset_transports_ptr(const fido_cbor_info_t *ci)
{
        return (ci->rsttransports.ptr);
}

size_t
fido_cbor_info_reset_transports_len(const fido_cbor_info_t *ci)
{
        return (ci->rsttransports.len);
}

int
fido_cbor_info_pin_policy(const fido_cbor_info_t *ci)
{
        return (ci->pinpolicy);
}

const unsigned char*
fido_cbor_info_pin_policy_url_ptr(const fido_cbor_info_t *ci)
{
        return (ci->pinpolicyurl.ptr);
}

size_t
fido_cbor_info_pin_policy_url_len(const fido_cbor_info_t *ci)
{
        return (ci->pinpolicyurl.len);
}

uint64_t
fido_cbor_info_maxpinlen(const fido_cbor_info_t *ci)
{
        return (ci->maxpinlen);
}

const uint8_t *
fido_cbor_info_cfgcmds_ptr(const fido_cbor_info_t *ci)
{
        return (ci->cfgcmds.ptr);
}

size_t
fido_cbor_info_cfgcmds_len(const fido_cbor_info_t *ci)
{
        return (ci->cfgcmds.len);
}

static int
decrypt(const fido_blob_t *secret, const char *info, const fido_blob_t *in,
    fido_blob_t *out)
{
        fido_blob_t key;
        unsigned char keybuf[16];
        int r = FIDO_ERR_INTERNAL;

        key.ptr = keybuf;
        key.len = sizeof(keybuf);

        fido_blob_reset(out);

        if (hkdf_sha256(key.ptr, key.len, info, secret) != 0) {
                fido_log_debug("%s: hkdf_sha256", __func__);
                goto fail;
        }
        if (aes128_cbc_dec(&key, in, out) != 0) {
                fido_log_debug("%s: aes128_cbc_dec", __func__);
                goto fail;
        }

        r = FIDO_OK;
fail:
        explicit_bzero(key.ptr, key.len);

        return r;
}

int
fido_cbor_info_decrypt(fido_cbor_info_t *ci, const unsigned char *ppuat,
    size_t ppuat_len)
{
        fido_blob_t secret;
        int r;

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

        if (fido_blob_set(&secret, ppuat, ppuat_len) != 0) {
                fido_log_debug("%s: fido_blob_set", __func__);
                r = FIDO_ERR_INTERNAL;
                goto fail;
        }

        if (!fido_blob_is_empty(&ci->encid) && (r = decrypt(&secret,
            "encIdentifier", &ci->encid, &ci->id)) != FIDO_OK) {
                fido_log_debug("%s: encIdentifier", __func__);
                goto fail;
        }

        if (!fido_blob_is_empty(&ci->encstate) && (r = decrypt(&secret,
            "encCredStoreState", &ci->encstate, &ci->state)) != FIDO_OK) {
                fido_log_debug("%s: encIdentifier", __func__);
                goto fail;
        }

        r = FIDO_OK;
fail:
        fido_blob_reset(&secret);

        return r;
}

Coverage Report

Created: 2026-04-08 06:32