diff options
Diffstat (limited to '')
| -rw-r--r-- | src/assert.c | 1170 |
1 files changed, 1170 insertions, 0 deletions
diff --git a/src/assert.c b/src/assert.c new file mode 100644 index 0000000..39d63bc --- /dev/null +++ b/src/assert.c @@ -0,0 +1,1170 @@ +/* + * Copyright (c) 2018-2023 Yubico AB. All rights reserved. + * Use of this source code is governed by a BSD-style + * license that can be found in the LICENSE file. + * SPDX-License-Identifier: BSD-2-Clause + */ + +#include <openssl/sha.h> + +#include "fido.h" +#include "fido/es256.h" +#include "fido/rs256.h" +#include "fido/eddsa.h" + +static int +adjust_assert_count(const cbor_item_t *key, const cbor_item_t *val, void *arg) +{ + fido_assert_t *assert = arg; + uint64_t n; + + /* numberOfCredentials; see section 6.2 */ + if (cbor_isa_uint(key) == false || + cbor_int_get_width(key) != CBOR_INT_8 || + cbor_get_uint8(key) != 5) { + fido_log_debug("%s: cbor_type", __func__); + return (0); /* ignore */ + } + + if (cbor_decode_uint64(val, &n) < 0 || n > SIZE_MAX) { + fido_log_debug("%s: cbor_decode_uint64", __func__); + return (-1); + } + + if (assert->stmt_len != 0 || assert->stmt_cnt != 1 || + (size_t)n < assert->stmt_cnt) { + fido_log_debug("%s: stmt_len=%zu, stmt_cnt=%zu, n=%zu", + __func__, assert->stmt_len, assert->stmt_cnt, (size_t)n); + return (-1); + } + + if (fido_assert_set_count(assert, (size_t)n) != FIDO_OK) { + fido_log_debug("%s: fido_assert_set_count", __func__); + return (-1); + } + + assert->stmt_len = 0; /* XXX */ + + return (0); +} + +static int +parse_assert_reply(const cbor_item_t *key, const cbor_item_t *val, void *arg) +{ + fido_assert_stmt *stmt = 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: /* credential id */ + return (cbor_decode_cred_id(val, &stmt->id)); + case 2: /* authdata */ + if (fido_blob_decode(val, &stmt->authdata_raw) < 0) { + fido_log_debug("%s: fido_blob_decode", __func__); + return (-1); + } + return (cbor_decode_assert_authdata(val, &stmt->authdata_cbor, + &stmt->authdata, &stmt->authdata_ext)); + case 3: /* signature */ + return (fido_blob_decode(val, &stmt->sig)); + case 4: /* user attributes */ + return (cbor_decode_user(val, &stmt->user)); + case 7: /* large blob key */ + return (fido_blob_decode(val, &stmt->largeblob_key)); + default: /* ignore */ + fido_log_debug("%s: cbor type", __func__); + return (0); + } +} + +static int +fido_dev_get_assert_tx(fido_dev_t *dev, fido_assert_t *assert, + const es256_pk_t *pk, const fido_blob_t *ecdh, const char *pin, int *ms) +{ + fido_blob_t f; + fido_opt_t uv = assert->uv; + cbor_item_t *argv[7]; + const uint8_t cmd = CTAP_CBOR_ASSERT; + int r; + + memset(argv, 0, sizeof(argv)); + memset(&f, 0, sizeof(f)); + + /* do we have everything we need? */ + if (assert->rp_id == NULL || assert->cdh.ptr == NULL) { + fido_log_debug("%s: rp_id=%p, cdh.ptr=%p", __func__, + (void *)assert->rp_id, (void *)assert->cdh.ptr); + r = FIDO_ERR_INVALID_ARGUMENT; + goto fail; + } + + if ((argv[0] = cbor_build_string(assert->rp_id)) == NULL || + (argv[1] = fido_blob_encode(&assert->cdh)) == NULL) { + fido_log_debug("%s: cbor encode", __func__); + r = FIDO_ERR_INTERNAL; + goto fail; + } + + /* allowed credentials */ + if (assert->allow_list.len) { + const fido_blob_array_t *cl = &assert->allow_list; + if ((argv[2] = cbor_encode_pubkey_list(cl)) == NULL) { + fido_log_debug("%s: cbor_encode_pubkey_list", __func__); + r = FIDO_ERR_INTERNAL; + goto fail; + } + } + + if (assert->ext.mask) + if ((argv[3] = cbor_encode_assert_ext(dev, &assert->ext, ecdh, + pk)) == NULL) { + fido_log_debug("%s: cbor_encode_assert_ext", __func__); + r = FIDO_ERR_INTERNAL; + goto fail; + } + + /* user verification */ + if (pin != NULL || (uv == FIDO_OPT_TRUE && + fido_dev_supports_permissions(dev))) { + if ((r = cbor_add_uv_params(dev, cmd, &assert->cdh, pk, ecdh, + pin, assert->rp_id, &argv[5], &argv[6], ms)) != FIDO_OK) { + fido_log_debug("%s: cbor_add_uv_params", __func__); + goto fail; + } + uv = FIDO_OPT_OMIT; + } + + /* options */ + if (assert->up != FIDO_OPT_OMIT || uv != FIDO_OPT_OMIT) + if ((argv[4] = cbor_encode_assert_opt(assert->up, uv)) == NULL) { + fido_log_debug("%s: cbor_encode_assert_opt", __func__); + r = FIDO_ERR_INTERNAL; + goto fail; + } + + /* frame and transmit */ + 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: + cbor_vector_free(argv, nitems(argv)); + free(f.ptr); + + return (r); +} + +static int +fido_dev_get_assert_rx(fido_dev_t *dev, fido_assert_t *assert, int *ms) +{ + unsigned char *msg; + int msglen; + int r; + + fido_assert_reset_rx(assert); + + 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; + } + + /* start with room for a single assertion */ + if ((assert->stmt = calloc(1, sizeof(fido_assert_stmt))) == NULL) { + r = FIDO_ERR_INTERNAL; + goto out; + } + assert->stmt_len = 0; + assert->stmt_cnt = 1; + + /* adjust as needed */ + if ((r = cbor_parse_reply(msg, (size_t)msglen, assert, + adjust_assert_count)) != FIDO_OK) { + fido_log_debug("%s: adjust_assert_count", __func__); + goto out; + } + + /* parse the first assertion */ + if ((r = cbor_parse_reply(msg, (size_t)msglen, &assert->stmt[0], + parse_assert_reply)) != FIDO_OK) { + fido_log_debug("%s: parse_assert_reply", __func__); + goto out; + } + assert->stmt_len = 1; + + r = FIDO_OK; +out: + freezero(msg, FIDO_MAXMSG); + + return (r); +} + +static int +fido_get_next_assert_tx(fido_dev_t *dev, int *ms) +{ + const unsigned char cbor[] = { CTAP_CBOR_NEXT_ASSERT }; + + 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_get_next_assert_rx(fido_dev_t *dev, fido_assert_t *assert, int *ms) +{ + unsigned char *msg; + int msglen; + int r; + + 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; + } + + /* sanity check */ + if (assert->stmt_len >= assert->stmt_cnt) { + fido_log_debug("%s: stmt_len=%zu, stmt_cnt=%zu", __func__, + assert->stmt_len, assert->stmt_cnt); + r = FIDO_ERR_INTERNAL; + goto out; + } + + if ((r = cbor_parse_reply(msg, (size_t)msglen, + &assert->stmt[assert->stmt_len], parse_assert_reply)) != FIDO_OK) { + fido_log_debug("%s: parse_assert_reply", __func__); + goto out; + } + + r = FIDO_OK; +out: + freezero(msg, FIDO_MAXMSG); + + return (r); +} + +static int +fido_dev_get_assert_wait(fido_dev_t *dev, fido_assert_t *assert, + const es256_pk_t *pk, const fido_blob_t *ecdh, const char *pin, int *ms) +{ + int r; + + if ((r = fido_dev_get_assert_tx(dev, assert, pk, ecdh, pin, + ms)) != FIDO_OK || + (r = fido_dev_get_assert_rx(dev, assert, ms)) != FIDO_OK) + return (r); + + while (assert->stmt_len < assert->stmt_cnt) { + if ((r = fido_get_next_assert_tx(dev, ms)) != FIDO_OK || + (r = fido_get_next_assert_rx(dev, assert, ms)) != FIDO_OK) + return (r); + assert->stmt_len++; + } + + return (FIDO_OK); +} + +static int +decrypt_hmac_secrets(const fido_dev_t *dev, fido_assert_t *assert, + const fido_blob_t *key) +{ + for (size_t i = 0; i < assert->stmt_cnt; i++) { + fido_assert_stmt *stmt = &assert->stmt[i]; + if (stmt->authdata_ext.hmac_secret_enc.ptr != NULL) { + if (aes256_cbc_dec(dev, key, + &stmt->authdata_ext.hmac_secret_enc, + &stmt->hmac_secret) < 0) { + fido_log_debug("%s: aes256_cbc_dec %zu", + __func__, i); + return (-1); + } + } + } + + return (0); +} + +int +fido_dev_get_assert(fido_dev_t *dev, fido_assert_t *assert, const char *pin) +{ + fido_blob_t *ecdh = NULL; + es256_pk_t *pk = NULL; + int ms = dev->timeout_ms; + int r; + +#ifdef USE_WINHELLO + if (dev->flags & FIDO_DEV_WINHELLO) + return (fido_winhello_get_assert(dev, assert, pin, ms)); +#endif + + if (assert->rp_id == NULL || assert->cdh.ptr == NULL) { + fido_log_debug("%s: rp_id=%p, cdh.ptr=%p", __func__, + (void *)assert->rp_id, (void *)assert->cdh.ptr); + return (FIDO_ERR_INVALID_ARGUMENT); + } + + if (fido_dev_is_fido2(dev) == false) { + if (pin != NULL || assert->ext.mask != 0) + return (FIDO_ERR_UNSUPPORTED_OPTION); + return (u2f_authenticate(dev, assert, &ms)); + } + + if (pin != NULL || (assert->uv == FIDO_OPT_TRUE && + fido_dev_supports_permissions(dev)) || + (assert->ext.mask & FIDO_EXT_HMAC_SECRET)) { + if ((r = fido_do_ecdh(dev, &pk, &ecdh, &ms)) != FIDO_OK) { + fido_log_debug("%s: fido_do_ecdh", __func__); + goto fail; + } + } + + r = fido_dev_get_assert_wait(dev, assert, pk, ecdh, pin, &ms); + if (r == FIDO_OK && (assert->ext.mask & FIDO_EXT_HMAC_SECRET)) + if (decrypt_hmac_secrets(dev, assert, ecdh) < 0) { + fido_log_debug("%s: decrypt_hmac_secrets", __func__); + r = FIDO_ERR_INTERNAL; + goto fail; + } + +fail: + es256_pk_free(&pk); + fido_blob_free(&ecdh); + + return (r); +} + +int +fido_check_flags(uint8_t flags, fido_opt_t up, fido_opt_t uv) +{ + fido_log_debug("%s: flags=%02x", __func__, flags); + fido_log_debug("%s: up=%d, uv=%d", __func__, up, uv); + + if (up == FIDO_OPT_TRUE && + (flags & CTAP_AUTHDATA_USER_PRESENT) == 0) { + fido_log_debug("%s: CTAP_AUTHDATA_USER_PRESENT", __func__); + return (-1); /* user not present */ + } + + if (uv == FIDO_OPT_TRUE && + (flags & CTAP_AUTHDATA_USER_VERIFIED) == 0) { + fido_log_debug("%s: CTAP_AUTHDATA_USER_VERIFIED", __func__); + return (-1); /* user not verified */ + } + + return (0); +} + +static int +check_extensions(int authdata_ext, int ext) +{ + /* XXX: largeBlobKey is not part of extensions map */ + ext &= ~FIDO_EXT_LARGEBLOB_KEY; + if (authdata_ext != ext) { + fido_log_debug("%s: authdata_ext=0x%x != ext=0x%x", __func__, + authdata_ext, ext); + return (-1); + } + + return (0); +} + +static int +get_es256_hash(fido_blob_t *dgst, const fido_blob_t *clientdata, + const fido_blob_t *authdata) +{ + const EVP_MD *md; + EVP_MD_CTX *ctx = NULL; + + 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, authdata->ptr, authdata->len) != 1 || + EVP_DigestUpdate(ctx, clientdata->ptr, clientdata->len) != 1 || + EVP_DigestFinal_ex(ctx, dgst->ptr, NULL) != 1) { + EVP_MD_CTX_free(ctx); + return (-1); + } + dgst->len = SHA256_DIGEST_LENGTH; + + EVP_MD_CTX_free(ctx); + + return (0); +} + +static int +get_es384_hash(fido_blob_t *dgst, const fido_blob_t *clientdata, + const fido_blob_t *authdata) +{ + const EVP_MD *md; + EVP_MD_CTX *ctx = NULL; + + if (dgst->len < SHA384_DIGEST_LENGTH || + (md = EVP_sha384()) == NULL || + (ctx = EVP_MD_CTX_new()) == NULL || + EVP_DigestInit_ex(ctx, md, NULL) != 1 || + EVP_DigestUpdate(ctx, authdata->ptr, authdata->len) != 1 || + EVP_DigestUpdate(ctx, clientdata->ptr, clientdata->len) != 1 || + EVP_DigestFinal_ex(ctx, dgst->ptr, NULL) != 1) { + EVP_MD_CTX_free(ctx); + return (-1); + } + dgst->len = SHA384_DIGEST_LENGTH; + + EVP_MD_CTX_free(ctx); + + return (0); +} + +static int +get_eddsa_hash(fido_blob_t *dgst, const fido_blob_t *clientdata, + const fido_blob_t *authdata) +{ + if (SIZE_MAX - authdata->len < clientdata->len || + dgst->len < authdata->len + clientdata->len) + return (-1); + + memcpy(dgst->ptr, authdata->ptr, authdata->len); + memcpy(dgst->ptr + authdata->len, clientdata->ptr, clientdata->len); + dgst->len = authdata->len + clientdata->len; + + return (0); +} + +int +fido_get_signed_hash(int cose_alg, fido_blob_t *dgst, + const fido_blob_t *clientdata, const fido_blob_t *authdata_cbor) +{ + cbor_item_t *item = NULL; + fido_blob_t authdata; + struct cbor_load_result cbor; + int ok = -1; + + fido_log_debug("%s: cose_alg=%d", __func__, cose_alg); + + if ((item = cbor_load(authdata_cbor->ptr, authdata_cbor->len, + &cbor)) == NULL || cbor_isa_bytestring(item) == false || + cbor_bytestring_is_definite(item) == false) { + fido_log_debug("%s: authdata", __func__); + goto fail; + } + authdata.ptr = cbor_bytestring_handle(item); + authdata.len = cbor_bytestring_length(item); + + switch (cose_alg) { + case COSE_ES256: + case COSE_RS256: + ok = get_es256_hash(dgst, clientdata, &authdata); + break; + case COSE_ES384: + ok = get_es384_hash(dgst, clientdata, &authdata); + break; + case COSE_EDDSA: + ok = get_eddsa_hash(dgst, clientdata, &authdata); + break; + default: + fido_log_debug("%s: unknown cose_alg", __func__); + break; + } +fail: + if (item != NULL) + cbor_decref(&item); + + return (ok); +} + +int +fido_assert_verify(const fido_assert_t *assert, size_t idx, int cose_alg, + const void *pk) +{ + unsigned char buf[1024]; /* XXX */ + fido_blob_t dgst; + const fido_assert_stmt *stmt = NULL; + int ok = -1; + int r; + + dgst.ptr = buf; + dgst.len = sizeof(buf); + + if (idx >= assert->stmt_len || pk == NULL) { + r = FIDO_ERR_INVALID_ARGUMENT; + goto out; + } + + stmt = &assert->stmt[idx]; + + /* do we have everything we need? */ + if (assert->cdh.ptr == NULL || assert->rp_id == NULL || + stmt->authdata_cbor.ptr == NULL || stmt->sig.ptr == NULL) { + fido_log_debug("%s: cdh=%p, rp_id=%s, authdata=%p, sig=%p", + __func__, (void *)assert->cdh.ptr, assert->rp_id, + (void *)stmt->authdata_cbor.ptr, (void *)stmt->sig.ptr); + r = FIDO_ERR_INVALID_ARGUMENT; + goto out; + } + + if (fido_check_flags(stmt->authdata.flags, assert->up, + assert->uv) < 0) { + fido_log_debug("%s: fido_check_flags", __func__); + r = FIDO_ERR_INVALID_PARAM; + goto out; + } + + if (check_extensions(stmt->authdata_ext.mask, assert->ext.mask) < 0) { + fido_log_debug("%s: check_extensions", __func__); + r = FIDO_ERR_INVALID_PARAM; + goto out; + } + + if (fido_check_rp_id(assert->rp_id, stmt->authdata.rp_id_hash) != 0) { + fido_log_debug("%s: fido_check_rp_id", __func__); + r = FIDO_ERR_INVALID_PARAM; + goto out; + } + + if (fido_get_signed_hash(cose_alg, &dgst, &assert->cdh, + &stmt->authdata_cbor) < 0) { + fido_log_debug("%s: fido_get_signed_hash", __func__); + r = FIDO_ERR_INTERNAL; + goto out; + } + + switch (cose_alg) { + case COSE_ES256: + ok = es256_pk_verify_sig(&dgst, pk, &stmt->sig); + break; + case COSE_ES384: + ok = es384_pk_verify_sig(&dgst, pk, &stmt->sig); + break; + case COSE_RS256: + ok = rs256_pk_verify_sig(&dgst, pk, &stmt->sig); + break; + case COSE_EDDSA: + ok = eddsa_pk_verify_sig(&dgst, pk, &stmt->sig); + break; + default: + fido_log_debug("%s: unsupported cose_alg %d", __func__, + cose_alg); + 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); +} + +int +fido_assert_set_clientdata(fido_assert_t *assert, const unsigned char *data, + size_t data_len) +{ + if (!fido_blob_is_empty(&assert->cdh) || + fido_blob_set(&assert->cd, data, data_len) < 0) { + return (FIDO_ERR_INVALID_ARGUMENT); + } + if (fido_sha256(&assert->cdh, data, data_len) < 0) { + fido_blob_reset(&assert->cd); + return (FIDO_ERR_INTERNAL); + } + + return (FIDO_OK); +} + +int +fido_assert_set_clientdata_hash(fido_assert_t *assert, + const unsigned char *hash, size_t hash_len) +{ + if (!fido_blob_is_empty(&assert->cd) || + fido_blob_set(&assert->cdh, hash, hash_len) < 0) + return (FIDO_ERR_INVALID_ARGUMENT); + + return (FIDO_OK); +} + +int +fido_assert_set_hmac_salt(fido_assert_t *assert, const unsigned char *salt, + size_t salt_len) +{ + if ((salt_len != 32 && salt_len != 64) || + fido_blob_set(&assert->ext.hmac_salt, salt, salt_len) < 0) + return (FIDO_ERR_INVALID_ARGUMENT); + + return (FIDO_OK); +} + +int +fido_assert_set_hmac_secret(fido_assert_t *assert, size_t idx, + const unsigned char *secret, size_t secret_len) +{ + if (idx >= assert->stmt_len || (secret_len != 32 && secret_len != 64) || + fido_blob_set(&assert->stmt[idx].hmac_secret, secret, + secret_len) < 0) + return (FIDO_ERR_INVALID_ARGUMENT); + + return (FIDO_OK); +} + +int +fido_assert_set_rp(fido_assert_t *assert, const char *id) +{ + if (assert->rp_id != NULL) { + free(assert->rp_id); + assert->rp_id = NULL; + } + + if (id == NULL) + return (FIDO_ERR_INVALID_ARGUMENT); + + if ((assert->rp_id = strdup(id)) == NULL) + return (FIDO_ERR_INTERNAL); + + return (FIDO_OK); +} + +#ifdef USE_WINHELLO +int +fido_assert_set_winhello_appid(fido_assert_t *assert, const char *id) +{ + if (assert->appid != NULL) { + free(assert->appid); + assert->appid = NULL; + } + + if (id == NULL) + return (FIDO_ERR_INVALID_ARGUMENT); + + if ((assert->appid = strdup(id)) == NULL) + return (FIDO_ERR_INTERNAL); + + return (FIDO_OK); +} +#else +int +fido_assert_set_winhello_appid(fido_assert_t *assert, const char *id) +{ + (void)assert; + (void)id; + + return (FIDO_ERR_UNSUPPORTED_EXTENSION); +} +#endif /* USE_WINHELLO */ + +int +fido_assert_allow_cred(fido_assert_t *assert, const unsigned char *ptr, + size_t len) +{ + fido_blob_t id; + fido_blob_t *list_ptr; + int r; + + memset(&id, 0, sizeof(id)); + + if (assert->allow_list.len == SIZE_MAX) { + r = FIDO_ERR_INVALID_ARGUMENT; + goto fail; + } + + if (fido_blob_set(&id, ptr, len) < 0 || (list_ptr = + recallocarray(assert->allow_list.ptr, assert->allow_list.len, + assert->allow_list.len + 1, sizeof(fido_blob_t))) == NULL) { + r = FIDO_ERR_INVALID_ARGUMENT; + goto fail; + } + + list_ptr[assert->allow_list.len++] = id; + assert->allow_list.ptr = list_ptr; + + return (FIDO_OK); +fail: + free(id.ptr); + + return (r); +} + +int +fido_assert_empty_allow_list(fido_assert_t *assert) +{ + fido_free_blob_array(&assert->allow_list); + memset(&assert->allow_list, 0, sizeof(assert->allow_list)); + + return (FIDO_OK); +} + +int +fido_assert_set_extensions(fido_assert_t *assert, int ext) +{ + if (ext == 0) + assert->ext.mask = 0; + else { + if ((ext & FIDO_EXT_ASSERT_MASK) != ext) + return (FIDO_ERR_INVALID_ARGUMENT); + assert->ext.mask |= ext; + } + + return (FIDO_OK); +} + +int +fido_assert_set_options(fido_assert_t *assert, bool up, bool uv) +{ + assert->up = up ? FIDO_OPT_TRUE : FIDO_OPT_FALSE; + assert->uv = uv ? FIDO_OPT_TRUE : FIDO_OPT_FALSE; + + return (FIDO_OK); +} + +int +fido_assert_set_up(fido_assert_t *assert, fido_opt_t up) +{ + assert->up = up; + + return (FIDO_OK); +} + +int +fido_assert_set_uv(fido_assert_t *assert, fido_opt_t uv) +{ + assert->uv = uv; + + return (FIDO_OK); +} + +const unsigned char * +fido_assert_clientdata_hash_ptr(const fido_assert_t *assert) +{ + return (assert->cdh.ptr); +} + +size_t +fido_assert_clientdata_hash_len(const fido_assert_t *assert) +{ + return (assert->cdh.len); +} + +fido_assert_t * +fido_assert_new(void) +{ + return (calloc(1, sizeof(fido_assert_t))); +} + +void +fido_assert_reset_tx(fido_assert_t *assert) +{ + free(assert->rp_id); + free(assert->appid); + fido_blob_reset(&assert->cd); + fido_blob_reset(&assert->cdh); + fido_blob_reset(&assert->ext.hmac_salt); + fido_assert_empty_allow_list(assert); + memset(&assert->ext, 0, sizeof(assert->ext)); + assert->rp_id = NULL; + assert->appid = NULL; + assert->up = FIDO_OPT_OMIT; + assert->uv = FIDO_OPT_OMIT; +} + +static void +fido_assert_reset_extattr(fido_assert_extattr_t *ext) +{ + fido_blob_reset(&ext->hmac_secret_enc); + fido_blob_reset(&ext->blob); + memset(ext, 0, sizeof(*ext)); +} + +void +fido_assert_reset_rx(fido_assert_t *assert) +{ + for (size_t i = 0; i < assert->stmt_cnt; i++) { + free(assert->stmt[i].user.icon); + free(assert->stmt[i].user.name); + free(assert->stmt[i].user.display_name); + fido_blob_reset(&assert->stmt[i].user.id); + fido_blob_reset(&assert->stmt[i].id); + fido_blob_reset(&assert->stmt[i].hmac_secret); + fido_blob_reset(&assert->stmt[i].authdata_cbor); + fido_blob_reset(&assert->stmt[i].authdata_raw); + fido_blob_reset(&assert->stmt[i].largeblob_key); + fido_blob_reset(&assert->stmt[i].sig); + fido_assert_reset_extattr(&assert->stmt[i].authdata_ext); + memset(&assert->stmt[i], 0, sizeof(assert->stmt[i])); + } + free(assert->stmt); + assert->stmt = NULL; + assert->stmt_len = 0; + assert->stmt_cnt = 0; +} + +void +fido_assert_free(fido_assert_t **assert_p) +{ + fido_assert_t *assert; + + if (assert_p == NULL || (assert = *assert_p) == NULL) + return; + fido_assert_reset_tx(assert); + fido_assert_reset_rx(assert); + free(assert); + *assert_p = NULL; +} + +size_t +fido_assert_count(const fido_assert_t *assert) +{ + return (assert->stmt_len); +} + +const char * +fido_assert_rp_id(const fido_assert_t *assert) +{ + return (assert->rp_id); +} + +uint8_t +fido_assert_flags(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (0); + + return (assert->stmt[idx].authdata.flags); +} + +uint32_t +fido_assert_sigcount(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (0); + + return (assert->stmt[idx].authdata.sigcount); +} + +const unsigned char * +fido_assert_authdata_ptr(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (NULL); + + return (assert->stmt[idx].authdata_cbor.ptr); +} + +size_t +fido_assert_authdata_len(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (0); + + return (assert->stmt[idx].authdata_cbor.len); +} + +const unsigned char * +fido_assert_authdata_raw_ptr(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (NULL); + + return (assert->stmt[idx].authdata_raw.ptr); +} + +size_t +fido_assert_authdata_raw_len(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (0); + + return (assert->stmt[idx].authdata_raw.len); +} + +const unsigned char * +fido_assert_sig_ptr(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (NULL); + + return (assert->stmt[idx].sig.ptr); +} + +size_t +fido_assert_sig_len(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (0); + + return (assert->stmt[idx].sig.len); +} + +const unsigned char * +fido_assert_id_ptr(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (NULL); + + return (assert->stmt[idx].id.ptr); +} + +size_t +fido_assert_id_len(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (0); + + return (assert->stmt[idx].id.len); +} + +const unsigned char * +fido_assert_user_id_ptr(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (NULL); + + return (assert->stmt[idx].user.id.ptr); +} + +size_t +fido_assert_user_id_len(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (0); + + return (assert->stmt[idx].user.id.len); +} + +const char * +fido_assert_user_icon(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (NULL); + + return (assert->stmt[idx].user.icon); +} + +const char * +fido_assert_user_name(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (NULL); + + return (assert->stmt[idx].user.name); +} + +const char * +fido_assert_user_display_name(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (NULL); + + return (assert->stmt[idx].user.display_name); +} + +const unsigned char * +fido_assert_hmac_secret_ptr(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (NULL); + + return (assert->stmt[idx].hmac_secret.ptr); +} + +size_t +fido_assert_hmac_secret_len(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (0); + + return (assert->stmt[idx].hmac_secret.len); +} + +const unsigned char * +fido_assert_largeblob_key_ptr(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (NULL); + + return (assert->stmt[idx].largeblob_key.ptr); +} + +size_t +fido_assert_largeblob_key_len(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (0); + + return (assert->stmt[idx].largeblob_key.len); +} + +const unsigned char * +fido_assert_blob_ptr(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (NULL); + + return (assert->stmt[idx].authdata_ext.blob.ptr); +} + +size_t +fido_assert_blob_len(const fido_assert_t *assert, size_t idx) +{ + if (idx >= assert->stmt_len) + return (0); + + return (assert->stmt[idx].authdata_ext.blob.len); +} + +static void +fido_assert_clean_authdata(fido_assert_stmt *stmt) +{ + fido_blob_reset(&stmt->authdata_cbor); + fido_blob_reset(&stmt->authdata_raw); + fido_assert_reset_extattr(&stmt->authdata_ext); + memset(&stmt->authdata, 0, sizeof(stmt->authdata)); +} + +int +fido_assert_set_authdata(fido_assert_t *assert, size_t idx, + const unsigned char *ptr, size_t len) +{ + cbor_item_t *item = NULL; + fido_assert_stmt *stmt = NULL; + struct cbor_load_result cbor; + int r; + + if (idx >= assert->stmt_len || ptr == NULL || len == 0) + return (FIDO_ERR_INVALID_ARGUMENT); + + stmt = &assert->stmt[idx]; + fido_assert_clean_authdata(stmt); + + if ((item = cbor_load(ptr, len, &cbor)) == NULL) { + fido_log_debug("%s: cbor_load", __func__); + r = FIDO_ERR_INVALID_ARGUMENT; + goto fail; + } + + if (fido_blob_decode(item, &stmt->authdata_raw) < 0) { + fido_log_debug("%s: fido_blob_decode", __func__); + r = FIDO_ERR_INTERNAL; + goto fail; + } + + if (cbor_decode_assert_authdata(item, &stmt->authdata_cbor, + &stmt->authdata, &stmt->authdata_ext) < 0) { + fido_log_debug("%s: cbor_decode_assert_authdata", __func__); + r = FIDO_ERR_INVALID_ARGUMENT; + goto fail; + } + + r = FIDO_OK; +fail: + if (item != NULL) + cbor_decref(&item); + + if (r != FIDO_OK) + fido_assert_clean_authdata(stmt); + + return (r); +} + +int +fido_assert_set_authdata_raw(fido_assert_t *assert, size_t idx, + const unsigned char *ptr, size_t len) +{ + cbor_item_t *item = NULL; + fido_assert_stmt *stmt = NULL; + int r; + + if (idx >= assert->stmt_len || ptr == NULL || len == 0) + return (FIDO_ERR_INVALID_ARGUMENT); + + stmt = &assert->stmt[idx]; + fido_assert_clean_authdata(stmt); + + if (fido_blob_set(&stmt->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_assert_authdata(item, &stmt->authdata_cbor, + &stmt->authdata, &stmt->authdata_ext) < 0) { + fido_log_debug("%s: cbor_decode_assert_authdata", __func__); + r = FIDO_ERR_INVALID_ARGUMENT; + goto fail; + } + + r = FIDO_OK; +fail: + if (item != NULL) + cbor_decref(&item); + + if (r != FIDO_OK) + fido_assert_clean_authdata(stmt); + + return (r); +} + +int +fido_assert_set_sig(fido_assert_t *a, size_t idx, const unsigned char *ptr, + size_t len) +{ + if (idx >= a->stmt_len || ptr == NULL || len == 0) + return (FIDO_ERR_INVALID_ARGUMENT); + if (fido_blob_set(&a->stmt[idx].sig, ptr, len) < 0) + return (FIDO_ERR_INTERNAL); + + return (FIDO_OK); +} + +/* XXX shrinking leaks memory; fortunately that shouldn't happen */ +int +fido_assert_set_count(fido_assert_t *assert, size_t n) +{ + void *new_stmt; + +#ifdef FIDO_FUZZ + if (n > UINT8_MAX) { + fido_log_debug("%s: n > UINT8_MAX", __func__); + return (FIDO_ERR_INTERNAL); + } +#endif + + new_stmt = recallocarray(assert->stmt, assert->stmt_cnt, n, + sizeof(fido_assert_stmt)); + if (new_stmt == NULL) + return (FIDO_ERR_INTERNAL); + + assert->stmt = new_stmt; + assert->stmt_cnt = n; + assert->stmt_len = n; + + return (FIDO_OK); +} |