/*
 * Copyright (c) 2018-2021 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.
 */

#include <openssl/sha.h>
#include <openssl/x509.h>

#include "fido.h"
#include "fido/es256.h"

#ifndef FIDO_MAXMSG_CRED
#define FIDO_MAXMSG_CRED        4096
#endif

static int
parse_makecred_reply(const cbor_item_t *key, const cbor_item_t *val, void *arg)
{
        fido_cred_t *cred = arg;

        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: /* fmt */
                return (cbor_decode_fmt(val, &cred->fmt));
        case 2: /* authdata */
                if (fido_blob_decode(val, &cred->authdata_raw) < 0) {
                        fido_log_debug("%s: fido_blob_decode", __func__);
                        return (-1);
                }
                return (cbor_decode_cred_authdata(val, cred->type,
                    &cred->authdata_cbor, &cred->authdata, &cred->attcred,
                    &cred->authdata_ext));
        case 3: /* attestation statement */
                return (cbor_decode_attstmt(val, &cred->attstmt));
        case 5: /* large blob key */
                return (fido_blob_decode(val, &cred->largeblob_key));
        default: /* ignore */
                fido_log_debug("%s: cbor type", __func__);
                return (0);
        }
}

static int
fido_dev_make_cred_tx(fido_dev_t *dev, fido_cred_t *cred, const char *pin,
    int *ms)
{
        fido_blob_t      f;
        fido_blob_t     *ecdh = NULL;
        fido_opt_t       uv = cred->uv;
        es256_pk_t      *pk = NULL;
        cbor_item_t     *argv[9];
        const uint8_t    cmd = CTAP_CBOR_MAKECRED;
        int              r;

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

        if (cred->cdh.ptr == NULL || cred->type == 0) {
                fido_log_debug("%s: cdh=%p, type=%d", __func__,
                    (void *)cred->cdh.ptr, cred->type);
                r = FIDO_ERR_INVALID_ARGUMENT;
                goto fail;
        }

        if ((argv[0] = fido_blob_encode(&cred->cdh)) == NULL ||
            (argv[1] = cbor_encode_rp_entity(&cred->rp)) == NULL ||
            (argv[2] = cbor_encode_user_entity(&cred->user)) == NULL ||
            (argv[3] = cbor_encode_pubkey_param(cred->type)) == NULL) {
                fido_log_debug("%s: cbor encode", __func__);
                r = FIDO_ERR_INTERNAL;
                goto fail;
        }

        /* excluded credentials */
        if (cred->excl.len)
                if ((argv[4] = cbor_encode_pubkey_list(&cred->excl)) == NULL) {
                        fido_log_debug("%s: cbor_encode_pubkey_list", __func__);
                        r = FIDO_ERR_INTERNAL;
                        goto fail;
                }

        /* extensions */
        if (cred->ext.mask)
                if ((argv[5] = cbor_encode_cred_ext(&cred->ext,
                    &cred->blob)) == NULL) {
                        fido_log_debug("%s: cbor_encode_cred_ext", __func__);
                        r = FIDO_ERR_INTERNAL;
                        goto fail;
                }

        /* user verification */
        if (pin != NULL || (uv == FIDO_OPT_TRUE &&
            fido_dev_supports_permissions(dev))) {
                if ((r = fido_do_ecdh(dev, &pk, &ecdh, ms)) != FIDO_OK) {
                        fido_log_debug("%s: fido_do_ecdh", __func__);
                        goto fail;
                }
                if ((r = cbor_add_uv_params(dev, cmd, &cred->cdh, pk, ecdh,
                    pin, cred->rp.id, &argv[7], &argv[8], ms)) != FIDO_OK) {
                        fido_log_debug("%s: cbor_add_uv_params", __func__);
                        goto fail;
                }
                uv = FIDO_OPT_OMIT;
        }

        /* options */
        if (cred->rk != FIDO_OPT_OMIT || uv != FIDO_OPT_OMIT)
                if ((argv[6] = cbor_encode_cred_opt(cred->rk, uv)) == NULL) {
                        fido_log_debug("%s: cbor_encode_cred_opt", __func__);
                        r = FIDO_ERR_INTERNAL;
                        goto fail;
                }

        /* framing and transmission */
        if (cbor_build_frame(cmd, argv, nitems(argv), &f) < 0 ||
            fido_tx(dev, CTAP_CMD_CBOR, f.ptr, f.len, ms) < 0) {
                fido_log_debug("%s: fido_tx", __func__);
                r = FIDO_ERR_TX;
                goto fail;
        }

        r = FIDO_OK;
fail:
        es256_pk_free(&pk);
        fido_blob_free(&ecdh);
        cbor_vector_free(argv, nitems(argv));
        free(f.ptr);

        return (r);
}

static int
fido_dev_make_cred_rx(fido_dev_t *dev, fido_cred_t *cred, int *ms)
{
        unsigned char   *reply;
        int              reply_len;
        int              r;

        fido_cred_reset_rx(cred);

        if ((reply = malloc(FIDO_MAXMSG_CRED)) == NULL) {
                r = FIDO_ERR_INTERNAL;
                goto fail;
        }

        if ((reply_len = fido_rx(dev, CTAP_CMD_CBOR, reply, FIDO_MAXMSG_CRED,
            ms)) < 0) {
                fido_log_debug("%s: fido_rx", __func__);
                r = FIDO_ERR_RX;
                goto fail;
        }

        if ((r = cbor_parse_reply(reply, (size_t)reply_len, cred,
            parse_makecred_reply)) != FIDO_OK) {
                fido_log_debug("%s: parse_makecred_reply", __func__);
                goto fail;
        }

        if (cred->fmt == NULL || fido_blob_is_empty(&cred->authdata_cbor) ||
            fido_blob_is_empty(&cred->attcred.id)) {
                r = FIDO_ERR_INVALID_CBOR;
                goto fail;
        }

        r = FIDO_OK;
fail:
        free(reply);

        if (r != FIDO_OK)
                fido_cred_reset_rx(cred);

        return (r);
}

static int
fido_dev_make_cred_wait(fido_dev_t *dev, fido_cred_t *cred, const char *pin,
    int *ms)
{
        int  r;

        if ((r = fido_dev_make_cred_tx(dev, cred, pin, ms)) != FIDO_OK ||
            (r = fido_dev_make_cred_rx(dev, cred, ms)) != FIDO_OK)
                return (r);

        return (FIDO_OK);
}

int
fido_dev_make_cred(fido_dev_t *dev, fido_cred_t *cred, const char *pin)
{
        int ms = dev->timeout_ms;

#ifdef USE_WINHELLO
        if (dev->flags & FIDO_DEV_WINHELLO)
                return (fido_winhello_make_cred(dev, cred, pin, ms));
#endif
        if (fido_dev_is_fido2(dev) == false) {
                if (pin != NULL || cred->rk == FIDO_OPT_TRUE ||
                    cred->ext.mask != 0)
                        return (FIDO_ERR_UNSUPPORTED_OPTION);
                return (u2f_register(dev, cred, &ms));
        }

        return (fido_dev_make_cred_wait(dev, cred, pin, &ms));
}

static int
check_extensions(const fido_cred_ext_t *authdata_ext,
    const fido_cred_ext_t *ext)
{
        fido_cred_ext_t  tmp;

        /* XXX: largeBlobKey is not part of the extensions map */
        memcpy(&tmp, ext, sizeof(tmp));
        tmp.mask &= ~FIDO_EXT_LARGEBLOB_KEY;

        return (timingsafe_bcmp(authdata_ext, &tmp, sizeof(*authdata_ext)));
}

int
fido_check_rp_id(const char *id, const unsigned char *obtained_hash)
{
        unsigned char expected_hash[SHA256_DIGEST_LENGTH];

        explicit_bzero(expected_hash, sizeof(expected_hash));

        if (SHA256((const unsigned char *)id, strlen(id),
            expected_hash) != expected_hash) {
                fido_log_debug("%s: sha256", __func__);
                return (-1);
        }

        return (timingsafe_bcmp(expected_hash, obtained_hash,
            SHA256_DIGEST_LENGTH));
}

static int
get_signed_hash_u2f(fido_blob_t *dgst, const unsigned char *rp_id,
    size_t rp_id_len, const fido_blob_t *clientdata, const fido_blob_t *id,
    const es256_pk_t *pk)
{
        const uint8_t    zero = 0;
        const uint8_t    four = 4; /* uncompressed point */
        const EVP_MD    *md = NULL;
        EVP_MD_CTX      *ctx = NULL;
        int              ok = -1;

        if (dgst->len != SHA256_DIGEST_LENGTH ||
            (md = EVP_sha256()) == NULL ||
            (ctx = EVP_MD_CTX_new()) == NULL ||
            EVP_DigestInit_ex(ctx, md, NULL) != 1 ||
            EVP_DigestUpdate(ctx, &zero, sizeof(zero)) != 1 ||
            EVP_DigestUpdate(ctx, rp_id, rp_id_len) != 1 ||
            EVP_DigestUpdate(ctx, clientdata->ptr, clientdata->len) != 1 ||
            EVP_DigestUpdate(ctx, id->ptr, id->len) != 1 ||
            EVP_DigestUpdate(ctx, &four, sizeof(four)) != 1 ||
            EVP_DigestUpdate(ctx, pk->x, sizeof(pk->x)) != 1 ||
            EVP_DigestUpdate(ctx, pk->y, sizeof(pk->y)) != 1 ||
            EVP_DigestFinal_ex(ctx, dgst->ptr, NULL) != 1) {
                fido_log_debug("%s: sha256", __func__);
                goto fail;
        }

        ok = 0;
fail:
        EVP_MD_CTX_free(ctx);

        return (ok);
}

static int
verify_attstmt(const fido_blob_t *dgst, const fido_attstmt_t *attstmt)
{
        BIO             *rawcert = NULL;
        X509            *cert = NULL;
        EVP_PKEY        *pkey = NULL;
        int              ok = -1;

        /* openssl needs ints */
        if (attstmt->x5c.len > INT_MAX) {
                fido_log_debug("%s: x5c.len=%zu", __func__, attstmt->x5c.len);
                return (-1);
        }

        /* fetch key from x509 */
        if ((rawcert = BIO_new_mem_buf(attstmt->x5c.ptr,
            (int)attstmt->x5c.len)) == NULL ||
            (cert = d2i_X509_bio(rawcert, NULL)) == NULL ||
            (pkey = X509_get_pubkey(cert)) == NULL) {
                fido_log_debug("%s: x509 key", __func__);
                goto fail;
        }

        switch (attstmt->alg) {
        case COSE_UNSPEC:
        case COSE_ES256:
                ok = es256_verify_sig(dgst, pkey, &attstmt->sig);
                break;
        case COSE_RS256:
                ok = rs256_verify_sig(dgst, pkey, &attstmt->sig);
                break;
        case COSE_RS1:
                ok = rs1_verify_sig(dgst, pkey, &attstmt->sig);
                break;
        case COSE_EDDSA:
                ok = eddsa_verify_sig(dgst, pkey, &attstmt->sig);
                break;
        default:
                fido_log_debug("%s: unknown alg %d", __func__, attstmt->alg);
                break;
        }

fail:
        BIO_free(rawcert);
        X509_free(cert);
        EVP_PKEY_free(pkey);

        return (ok);
}

int
fido_cred_verify(const fido_cred_t *cred)
{
        unsigned char   buf[SHA256_DIGEST_LENGTH];
        fido_blob_t     dgst;
        int             r;

        dgst.ptr = buf;
        dgst.len = sizeof(buf);

        /* do we have everything we need? */
        if (cred->cdh.ptr == NULL || cred->authdata_cbor.ptr == NULL ||
            cred->attstmt.x5c.ptr == NULL || cred->attstmt.sig.ptr == NULL ||
            cred->fmt == NULL || cred->attcred.id.ptr == NULL ||
            cred->rp.id == NULL) {
                fido_log_debug("%s: cdh=%p, authdata=%p, x5c=%p, sig=%p, "
                    "fmt=%p id=%p, rp.id=%s", __func__, (void *)cred->cdh.ptr,
                    (void *)cred->authdata_cbor.ptr,
                    (void *)cred->attstmt.x5c.ptr,
                    (void *)cred->attstmt.sig.ptr, (void *)cred->fmt,
                    (void *)cred->attcred.id.ptr, cred->rp.id);
                r = FIDO_ERR_INVALID_ARGUMENT;
                goto out;
        }

        if (fido_check_rp_id(cred->rp.id, cred->authdata.rp_id_hash) != 0) {
                fido_log_debug("%s: fido_check_rp_id", __func__);
                r = FIDO_ERR_INVALID_PARAM;
                goto out;
        }

        if (fido_check_flags(cred->authdata.flags, FIDO_OPT_TRUE,
            cred->uv) < 0) {
                fido_log_debug("%s: fido_check_flags", __func__);
                r = FIDO_ERR_INVALID_PARAM;
                goto out;
        }

        if (check_extensions(&cred->authdata_ext, &cred->ext) != 0) {
                fido_log_debug("%s: check_extensions", __func__);
                r = FIDO_ERR_INVALID_PARAM;
                goto out;
        }

        if (!strcmp(cred->fmt, "packed")) {
                if (fido_get_signed_hash(COSE_ES256, &dgst, &cred->cdh,
                    &cred->authdata_cbor) < 0) {
                        fido_log_debug("%s: fido_get_signed_hash", __func__);
                        r = FIDO_ERR_INTERNAL;
                        goto out;
                }
        } else if (!strcmp(cred->fmt, "fido-u2f")) {
                if (get_signed_hash_u2f(&dgst, cred->authdata.rp_id_hash,
                    sizeof(cred->authdata.rp_id_hash), &cred->cdh,
                    &cred->attcred.id, &cred->attcred.pubkey.es256) < 0) {
                        fido_log_debug("%s: get_signed_hash_u2f", __func__);
                        r = FIDO_ERR_INTERNAL;
                        goto out;
                }
        } else if (!strcmp(cred->fmt, "tpm")) {
                if (fido_get_signed_hash_tpm(&dgst, &cred->cdh,
                    &cred->authdata_raw, &cred->attstmt, &cred->attcred) < 0) {
                        fido_log_debug("%s: fido_get_signed_hash_tpm", __func__);
                        r = FIDO_ERR_INTERNAL;
                        goto out;
                }
        } else {
                fido_log_debug("%s: unknown fmt %s", __func__, cred->fmt);
                r = FIDO_ERR_INVALID_ARGUMENT;
                goto out;
        }

        if (verify_attstmt(&dgst, &cred->attstmt) < 0) {
                fido_log_debug("%s: verify_attstmt", __func__);
                r = FIDO_ERR_INVALID_SIG;
                goto out;
        }

        r = FIDO_OK;
out:
        explicit_bzero(buf, sizeof(buf));

        return (r);
}

int
fido_cred_verify_self(const fido_cred_t *cred)
{
        unsigned char   buf[1024]; /* XXX */
        fido_blob_t     dgst;
        int             ok = -1;
        int             r;

        dgst.ptr = buf;
        dgst.len = sizeof(buf);

        /* do we have everything we need? */
        if (cred->cdh.ptr == NULL || cred->authdata_cbor.ptr == NULL ||
            cred->attstmt.x5c.ptr != NULL || cred->attstmt.sig.ptr == NULL ||
            cred->fmt == NULL || cred->attcred.id.ptr == NULL ||
            cred->rp.id == NULL) {
                fido_log_debug("%s: cdh=%p, authdata=%p, x5c=%p, sig=%p, "
                    "fmt=%p id=%p, rp.id=%s", __func__, (void *)cred->cdh.ptr,
                    (void *)cred->authdata_cbor.ptr,
                    (void *)cred->attstmt.x5c.ptr,
                    (void *)cred->attstmt.sig.ptr, (void *)cred->fmt,
                    (void *)cred->attcred.id.ptr, cred->rp.id);
                r = FIDO_ERR_INVALID_ARGUMENT;
                goto out;
        }

        if (fido_check_rp_id(cred->rp.id, cred->authdata.rp_id_hash) != 0) {
                fido_log_debug("%s: fido_check_rp_id", __func__);
                r = FIDO_ERR_INVALID_PARAM;
                goto out;
        }

        if (fido_check_flags(cred->authdata.flags, FIDO_OPT_TRUE,
            cred->uv) < 0) {
                fido_log_debug("%s: fido_check_flags", __func__);
                r = FIDO_ERR_INVALID_PARAM;
                goto out;
        }

        if (check_extensions(&cred->authdata_ext, &cred->ext) != 0) {
                fido_log_debug("%s: check_extensions", __func__);
                r = FIDO_ERR_INVALID_PARAM;
                goto out;
        }

        if (!strcmp(cred->fmt, "packed")) {
                if (fido_get_signed_hash(cred->attcred.type, &dgst, &cred->cdh,
                    &cred->authdata_cbor) < 0) {
                        fido_log_debug("%s: fido_get_signed_hash", __func__);
                        r = FIDO_ERR_INTERNAL;
                        goto out;
                }
        } else if (!strcmp(cred->fmt, "fido-u2f")) {
                if (get_signed_hash_u2f(&dgst, cred->authdata.rp_id_hash,
                    sizeof(cred->authdata.rp_id_hash), &cred->cdh,
                    &cred->attcred.id, &cred->attcred.pubkey.es256) < 0) {
                        fido_log_debug("%s: get_signed_hash_u2f", __func__);
                        r = FIDO_ERR_INTERNAL;
                        goto out;
                }
        } else {
                fido_log_debug("%s: unknown fmt %s", __func__, cred->fmt);
                r = FIDO_ERR_INVALID_ARGUMENT;
                goto out;
        }

        switch (cred->attcred.type) {
        case COSE_ES256:
                ok = es256_pk_verify_sig(&dgst, &cred->attcred.pubkey.es256,
                    &cred->attstmt.sig);
                break;
        case COSE_RS256:
                ok = rs256_pk_verify_sig(&dgst, &cred->attcred.pubkey.rs256,
                    &cred->attstmt.sig);
                break;
        case COSE_EDDSA:
                ok = eddsa_pk_verify_sig(&dgst, &cred->attcred.pubkey.eddsa,
                    &cred->attstmt.sig);
                break;
        default:
                fido_log_debug("%s: unsupported cose_alg %d", __func__,
                    cred->attcred.type);
                r = FIDO_ERR_UNSUPPORTED_OPTION;
                goto out;
        }

        if (ok < 0)
                r = FIDO_ERR_INVALID_SIG;
        else
                r = FIDO_OK;

out:
        explicit_bzero(buf, sizeof(buf));

        return (r);
}

fido_cred_t *
fido_cred_new(void)
{
        return (calloc(1, sizeof(fido_cred_t)));
}

static void
fido_cred_clean_authdata(fido_cred_t *cred)
{
        fido_blob_reset(&cred->authdata_cbor);
        fido_blob_reset(&cred->authdata_raw);
        fido_blob_reset(&cred->attcred.id);

        memset(&cred->authdata_ext, 0, sizeof(cred->authdata_ext));
        memset(&cred->authdata, 0, sizeof(cred->authdata));
        memset(&cred->attcred, 0, sizeof(cred->attcred));
}

static void
fido_cred_clean_attstmt(fido_attstmt_t *attstmt)
{
        fido_blob_reset(&attstmt->certinfo);
        fido_blob_reset(&attstmt->pubarea);
        fido_blob_reset(&attstmt->cbor);
        fido_blob_reset(&attstmt->x5c);
        fido_blob_reset(&attstmt->sig);

        memset(attstmt, 0, sizeof(*attstmt));
}

void
fido_cred_reset_tx(fido_cred_t *cred)
{
        fido_blob_reset(&cred->cd);
        fido_blob_reset(&cred->cdh);
        fido_blob_reset(&cred->user.id);
        fido_blob_reset(&cred->blob);

        free(cred->rp.id);
        free(cred->rp.name);
        free(cred->user.icon);
        free(cred->user.name);
        free(cred->user.display_name);
        fido_free_blob_array(&cred->excl);

        memset(&cred->rp, 0, sizeof(cred->rp));
        memset(&cred->user, 0, sizeof(cred->user));
        memset(&cred->excl, 0, sizeof(cred->excl));
        memset(&cred->ext, 0, sizeof(cred->ext));

        cred->type = 0;
        cred->rk = FIDO_OPT_OMIT;
        cred->uv = FIDO_OPT_OMIT;
}

void
fido_cred_reset_rx(fido_cred_t *cred)
{
        free(cred->fmt);
        cred->fmt = NULL;
        fido_cred_clean_authdata(cred);
        fido_cred_clean_attstmt(&cred->attstmt);
        fido_blob_reset(&cred->largeblob_key);
}

void
fido_cred_free(fido_cred_t **cred_p)
{
        fido_cred_t *cred;

        if (cred_p == NULL || (cred = *cred_p) == NULL)
                return;
        fido_cred_reset_tx(cred);
        fido_cred_reset_rx(cred);
        free(cred);
        *cred_p = NULL;
}

int
fido_cred_set_authdata(fido_cred_t *cred, const unsigned char *ptr, size_t len)
{
        cbor_item_t             *item = NULL;
        struct cbor_load_result  cbor;
        int                      r = FIDO_ERR_INVALID_ARGUMENT;

        fido_cred_clean_authdata(cred);

        if (ptr == NULL || len == 0)
                goto fail;

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

        if (fido_blob_decode(item, &cred->authdata_raw) < 0) {
                fido_log_debug("%s: fido_blob_decode", __func__);
                goto fail;
        }

        if (cbor_decode_cred_authdata(item, cred->type, &cred->authdata_cbor,
            &cred->authdata, &cred->attcred, &cred->authdata_ext) < 0) {
                fido_log_debug("%s: cbor_decode_cred_authdata", __func__);
                goto fail;
        }

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

        if (r != FIDO_OK)
                fido_cred_clean_authdata(cred);

        return (r);
}

int
fido_cred_set_authdata_raw(fido_cred_t *cred, const unsigned char *ptr,
    size_t len)
{
        cbor_item_t     *item = NULL;
        int              r = FIDO_ERR_INVALID_ARGUMENT;

        fido_cred_clean_authdata(cred);

        if (ptr == NULL || len == 0)
                goto fail;

        if (fido_blob_set(&cred->authdata_raw, ptr, len) < 0) {
                fido_log_debug("%s: fido_blob_set", __func__);
                r = FIDO_ERR_INTERNAL;
                goto fail;
        }

        if ((item = cbor_build_bytestring(ptr, len)) == NULL) {
                fido_log_debug("%s: cbor_build_bytestring", __func__);
                r = FIDO_ERR_INTERNAL;
                goto fail;
        }

        if (cbor_decode_cred_authdata(item, cred->type, &cred->authdata_cbor,
            &cred->authdata, &cred->attcred, &cred->authdata_ext) < 0) {
                fido_log_debug("%s: cbor_decode_cred_authdata", __func__);
                goto fail;
        }

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

        if (r != FIDO_OK)
                fido_cred_clean_authdata(cred);

        return (r);
}

int
fido_cred_set_id(fido_cred_t *cred, const unsigned char *ptr, size_t len)
{
        if (fido_blob_set(&cred->attcred.id, ptr, len) < 0)
                return (FIDO_ERR_INVALID_ARGUMENT);

        return (FIDO_OK);
}

int
fido_cred_set_x509(fido_cred_t *cred, const unsigned char *ptr, size_t len)
{
        if (fido_blob_set(&cred->attstmt.x5c, ptr, len) < 0)
                return (FIDO_ERR_INVALID_ARGUMENT);

        return (FIDO_OK);
}

int
fido_cred_set_sig(fido_cred_t *cred, const unsigned char *ptr, size_t len)
{
        if (fido_blob_set(&cred->attstmt.sig, ptr, len) < 0)
                return (FIDO_ERR_INVALID_ARGUMENT);

        return (FIDO_OK);
}

int
fido_cred_set_attstmt(fido_cred_t *cred, const unsigned char *ptr, size_t len)
{
        cbor_item_t             *item = NULL;
        struct cbor_load_result  cbor;
        int                      r = FIDO_ERR_INVALID_ARGUMENT;

        fido_cred_clean_attstmt(&cred->attstmt);

        if (ptr == NULL || len == 0)
                goto fail;

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

        if (cbor_decode_attstmt(item, &cred->attstmt) < 0) {
                fido_log_debug("%s: cbor_decode_attstmt", __func__);
                goto fail;
        }

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

        if (r != FIDO_OK)
                fido_cred_clean_attstmt(&cred->attstmt);

        return (r);
}

int
fido_cred_exclude(fido_cred_t *cred, const unsigned char *id_ptr, size_t id_len)
{
        fido_blob_t id_blob;
        fido_blob_t *list_ptr;

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

        if (fido_blob_set(&id_blob, id_ptr, id_len) < 0)
                return (FIDO_ERR_INVALID_ARGUMENT);

        if (cred->excl.len == SIZE_MAX) {
                free(id_blob.ptr);
                return (FIDO_ERR_INVALID_ARGUMENT);
        }

        if ((list_ptr = recallocarray(cred->excl.ptr, cred->excl.len,
            cred->excl.len + 1, sizeof(fido_blob_t))) == NULL) {
                free(id_blob.ptr);
                return (FIDO_ERR_INTERNAL);
        }

        list_ptr[cred->excl.len++] = id_blob;
        cred->excl.ptr = list_ptr;

        return (FIDO_OK);
}

int
fido_cred_set_clientdata(fido_cred_t *cred, const unsigned char *data,
    size_t data_len)
{
        if (!fido_blob_is_empty(&cred->cdh) ||
            fido_blob_set(&cred->cd, data, data_len) < 0) {
                return (FIDO_ERR_INVALID_ARGUMENT);
        }
        if (fido_sha256(&cred->cdh, data, data_len) < 0) {
                fido_blob_reset(&cred->cd);
                return (FIDO_ERR_INTERNAL);
        }

        return (FIDO_OK);
}

int
fido_cred_set_clientdata_hash(fido_cred_t *cred, const unsigned char *hash,
    size_t hash_len)
{
        if (!fido_blob_is_empty(&cred->cd) ||
            fido_blob_set(&cred->cdh, hash, hash_len) < 0)
                return (FIDO_ERR_INVALID_ARGUMENT);

        return (FIDO_OK);
}

int
fido_cred_set_rp(fido_cred_t *cred, const char *id, const char *name)
{
        fido_rp_t *rp = &cred->rp;

        if (rp->id != NULL) {
                free(rp->id);
                rp->id = NULL;
        }
        if (rp->name != NULL) {
                free(rp->name);
                rp->name = NULL;
        }

        if (id != NULL && (rp->id = strdup(id)) == NULL)
                goto fail;
        if (name != NULL && (rp->name = strdup(name)) == NULL)
                goto fail;

        return (FIDO_OK);
fail:
        free(rp->id);
        free(rp->name);
        rp->id = NULL;
        rp->name = NULL;

        return (FIDO_ERR_INTERNAL);
}

int
fido_cred_set_user(fido_cred_t *cred, const unsigned char *user_id,
    size_t user_id_len, const char *name, const char *display_name,
    const char *icon)
{
        fido_user_t *up = &cred->user;

        if (up->id.ptr != NULL) {
                free(up->id.ptr);
                up->id.ptr = NULL;
                up->id.len = 0;
        }
        if (up->name != NULL) {
                free(up->name);
                up->name = NULL;
        }
        if (up->display_name != NULL) {
                free(up->display_name);
                up->display_name = NULL;
        }
        if (up->icon != NULL) {
                free(up->icon);
                up->icon = NULL;
        }

        if (user_id != NULL && fido_blob_set(&up->id, user_id, user_id_len) < 0)
                goto fail;
        if (name != NULL && (up->name = strdup(name)) == NULL)
                goto fail;
        if (display_name != NULL &&
            (up->display_name = strdup(display_name)) == NULL)
                goto fail;
        if (icon != NULL && (up->icon = strdup(icon)) == NULL)
                goto fail;

        return (FIDO_OK);
fail:
        free(up->id.ptr);
        free(up->name);
        free(up->display_name);
        free(up->icon);

        up->id.ptr = NULL;
        up->id.len = 0;
        up->name = NULL;
        up->display_name = NULL;
        up->icon = NULL;

        return (FIDO_ERR_INTERNAL);
}

int
fido_cred_set_extensions(fido_cred_t *cred, int ext)
{
        if (ext == 0)
                cred->ext.mask = 0;
        else {
                if ((ext & FIDO_EXT_CRED_MASK) != ext)
                        return (FIDO_ERR_INVALID_ARGUMENT);
                cred->ext.mask |= ext;
        }

        return (FIDO_OK);
}

int
fido_cred_set_options(fido_cred_t *cred, bool rk, bool uv)
{
        cred->rk = rk ? FIDO_OPT_TRUE : FIDO_OPT_FALSE;
        cred->uv = uv ? FIDO_OPT_TRUE : FIDO_OPT_FALSE;

        return (FIDO_OK);
}

int
fido_cred_set_rk(fido_cred_t *cred, fido_opt_t rk)
{
        cred->rk = rk;

        return (FIDO_OK);
}

int
fido_cred_set_uv(fido_cred_t *cred, fido_opt_t uv)
{
        cred->uv = uv;

        return (FIDO_OK);
}

int
fido_cred_set_prot(fido_cred_t *cred, int prot)
{
        if (prot == 0) {
                cred->ext.mask &= ~FIDO_EXT_CRED_PROTECT;
                cred->ext.prot = 0;
        } else {
                if (prot != FIDO_CRED_PROT_UV_OPTIONAL &&
                    prot != FIDO_CRED_PROT_UV_OPTIONAL_WITH_ID &&
                    prot != FIDO_CRED_PROT_UV_REQUIRED)
                        return (FIDO_ERR_INVALID_ARGUMENT);

                cred->ext.mask |= FIDO_EXT_CRED_PROTECT;
                cred->ext.prot = prot;
        }

        return (FIDO_OK);
}

int
fido_cred_set_pin_minlen(fido_cred_t *cred, size_t len)
{
        if (len == 0)
                cred->ext.mask &= ~FIDO_EXT_MINPINLEN;
        else
                cred->ext.mask |= FIDO_EXT_MINPINLEN;

        cred->ext.minpinlen = len;

        return (FIDO_OK);
}

int
fido_cred_set_blob(fido_cred_t *cred, const unsigned char *ptr, size_t len)
{
        if (ptr == NULL || len == 0)
                return (FIDO_ERR_INVALID_ARGUMENT);
        if (fido_blob_set(&cred->blob, ptr, len) < 0)
                return (FIDO_ERR_INTERNAL);

        cred->ext.mask |= FIDO_EXT_CRED_BLOB;

        return (FIDO_OK);
}

int
fido_cred_set_fmt(fido_cred_t *cred, const char *fmt)
{
        free(cred->fmt);
        cred->fmt = NULL;

        if (fmt == NULL)
                return (FIDO_ERR_INVALID_ARGUMENT);

        if (strcmp(fmt, "packed") && strcmp(fmt, "fido-u2f") &&
            strcmp(fmt, "none") && strcmp(fmt, "tpm"))
                return (FIDO_ERR_INVALID_ARGUMENT);

        if ((cred->fmt = strdup(fmt)) == NULL)
                return (FIDO_ERR_INTERNAL);

        return (FIDO_OK);
}

int
fido_cred_set_type(fido_cred_t *cred, int cose_alg)
{
        if ((cose_alg != COSE_ES256 && cose_alg != COSE_RS256 &&
            cose_alg != COSE_EDDSA) || cred->type != 0)
                return (FIDO_ERR_INVALID_ARGUMENT);

        cred->type = cose_alg;

        return (FIDO_OK);
}

int
fido_cred_type(const fido_cred_t *cred)
{
        return (cred->type);
}

uint8_t
fido_cred_flags(const fido_cred_t *cred)
{
        return (cred->authdata.flags);
}

uint32_t
fido_cred_sigcount(const fido_cred_t *cred)
{
        return (cred->authdata.sigcount);
}

const unsigned char *
fido_cred_clientdata_hash_ptr(const fido_cred_t *cred)
{
        return (cred->cdh.ptr);
}

size_t
fido_cred_clientdata_hash_len(const fido_cred_t *cred)
{
        return (cred->cdh.len);
}

const unsigned char *
fido_cred_x5c_ptr(const fido_cred_t *cred)
{
        return (cred->attstmt.x5c.ptr);
}

size_t
fido_cred_x5c_len(const fido_cred_t *cred)
{
        return (cred->attstmt.x5c.len);
}

const unsigned char *
fido_cred_sig_ptr(const fido_cred_t *cred)
{
        return (cred->attstmt.sig.ptr);
}

size_t
fido_cred_sig_len(const fido_cred_t *cred)
{
        return (cred->attstmt.sig.len);
}

const unsigned char *
fido_cred_authdata_ptr(const fido_cred_t *cred)
{
        return (cred->authdata_cbor.ptr);
}

size_t
fido_cred_authdata_len(const fido_cred_t *cred)
{
        return (cred->authdata_cbor.len);
}

const unsigned char *
fido_cred_authdata_raw_ptr(const fido_cred_t *cred)
{
        return (cred->authdata_raw.ptr);
}

size_t
fido_cred_authdata_raw_len(const fido_cred_t *cred)
{
        return (cred->authdata_raw.len);
}

const unsigned char *
fido_cred_attstmt_ptr(const fido_cred_t *cred)
{
        return (cred->attstmt.cbor.ptr);
}

size_t
fido_cred_attstmt_len(const fido_cred_t *cred)
{
        return (cred->attstmt.cbor.len);
}

const unsigned char *
fido_cred_pubkey_ptr(const fido_cred_t *cred)
{
        const void *ptr;

        switch (cred->attcred.type) {
        case COSE_ES256:
                ptr = &cred->attcred.pubkey.es256;
                break;
        case COSE_RS256:
                ptr = &cred->attcred.pubkey.rs256;
                break;
        case COSE_EDDSA:
                ptr = &cred->attcred.pubkey.eddsa;
                break;
        default:
                ptr = NULL;
                break;
        }

        return (ptr);
}

size_t
fido_cred_pubkey_len(const fido_cred_t *cred)
{
        size_t len;

        switch (cred->attcred.type) {
        case COSE_ES256:
                len = sizeof(cred->attcred.pubkey.es256);
                break;
        case COSE_RS256:
                len = sizeof(cred->attcred.pubkey.rs256);
                break;
        case COSE_EDDSA:
                len = sizeof(cred->attcred.pubkey.eddsa);
                break;
        default:
                len = 0;
                break;
        }

        return (len);
}

const unsigned char *
fido_cred_id_ptr(const fido_cred_t *cred)
{
        return (cred->attcred.id.ptr);
}

size_t
fido_cred_id_len(const fido_cred_t *cred)
{
        return (cred->attcred.id.len);
}

const unsigned char *
fido_cred_aaguid_ptr(const fido_cred_t *cred)
{
        return (cred->attcred.aaguid);
}

size_t
fido_cred_aaguid_len(const fido_cred_t *cred)
{
        return (sizeof(cred->attcred.aaguid));
}

int
fido_cred_prot(const fido_cred_t *cred)
{
        return (cred->ext.prot);
}

size_t
fido_cred_pin_minlen(const fido_cred_t *cred)
{
        return (cred->ext.minpinlen);
}

const char *
fido_cred_fmt(const fido_cred_t *cred)
{
        return (cred->fmt);
}

const char *
fido_cred_rp_id(const fido_cred_t *cred)
{
        return (cred->rp.id);
}

const char *
fido_cred_rp_name(const fido_cred_t *cred)
{
        return (cred->rp.name);
}

const char *
fido_cred_user_name(const fido_cred_t *cred)
{
        return (cred->user.name);
}

const char *
fido_cred_display_name(const fido_cred_t *cred)
{
        return (cred->user.display_name);
}

const unsigned char *
fido_cred_user_id_ptr(const fido_cred_t *cred)
{
        return (cred->user.id.ptr);
}

size_t
fido_cred_user_id_len(const fido_cred_t *cred)
{
        return (cred->user.id.len);
}

const unsigned char *
fido_cred_largeblob_key_ptr(const fido_cred_t *cred)
{
        return (cred->largeblob_key.ptr);
}

size_t
fido_cred_largeblob_key_len(const fido_cred_t *cred)
{
        return (cred->largeblob_key.len);
}