/libfido2/src/es256.c

Source
/*
 * Copyright (c) 2018-2022 Yubico AB. All rights reserved.
 * Use of this source code is governed by a BSD-style
 * license that can be found in the LICENSE file.
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <openssl/bn.h>
#include <openssl/ecdsa.h>
#include <openssl/obj_mac.h>

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

#if OPENSSL_VERSION_NUMBER >= 0x30000000
#define get0_EC_KEY(x)  EVP_PKEY_get0_EC_KEY((x))
#else
#define get0_EC_KEY(x)  EVP_PKEY_get0((x))
#endif

static const int es256_nid = NID_X9_62_prime256v1;

static int
decode_coord(const cbor_item_t *item, void *xy, size_t xy_len)
{
        if (cbor_isa_bytestring(item) == false ||
            cbor_bytestring_is_definite(item) == false ||
            cbor_bytestring_length(item) != xy_len) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        memcpy(xy, cbor_bytestring_handle(item), xy_len);

        return (0);
}

static int
decode_pubkey_point(const cbor_item_t *key, const cbor_item_t *val, void *arg)
{
        es256_pk_t *k = arg;

        if (cbor_isa_negint(key) == false ||
            cbor_int_get_width(key) != CBOR_INT_8)
                return (0); /* ignore */

        switch (cbor_get_uint8(key)) {
        case 1: /* x coordinate */
                return (decode_coord(val, &k->x, sizeof(k->x)));
        case 2: /* y coordinate */
                return (decode_coord(val, &k->y, sizeof(k->y)));
        }

        return (0); /* ignore */
}

int
es256_pk_decode(const cbor_item_t *item, es256_pk_t *k)
{
        if (cbor_isa_map(item) == false ||
            cbor_map_is_definite(item) == false ||
            cbor_map_iter(item, k, decode_pubkey_point) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        return (0);
}

cbor_item_t *
es256_pk_encode(const es256_pk_t *pk, int ecdh)
{
        cbor_item_t             *item = NULL;
        struct cbor_pair         argv[5];
        int                      alg;
        int                      ok = -1;

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

        if ((item = cbor_new_definite_map(5)) == NULL)
                goto fail;

        /* kty */
        if ((argv[0].key = cbor_build_uint8(1)) == NULL ||
            (argv[0].value = cbor_build_uint8(2)) == NULL ||
            !cbor_map_add(item, argv[0]))
                goto fail;

        /*
         * "The COSEAlgorithmIdentifier used is -25 (ECDH-ES +
         * HKDF-256) although this is NOT the algorithm actually
         * used. Setting this to a different value may result in
         * compatibility issues."
         */
        if (ecdh)
                alg = COSE_ECDH_ES256;
        else
                alg = COSE_ES256;

        /* alg */
        if ((argv[1].key = cbor_build_uint8(3)) == NULL ||
            (argv[1].value = cbor_build_negint8((uint8_t)(-alg - 1))) == NULL ||
            !cbor_map_add(item, argv[1]))
                goto fail;

        /* crv */
        if ((argv[2].key = cbor_build_negint8(0)) == NULL ||
            (argv[2].value = cbor_build_uint8(1)) == NULL ||
            !cbor_map_add(item, argv[2]))
                goto fail;

        /* x */
        if ((argv[3].key = cbor_build_negint8(1)) == NULL ||
            (argv[3].value = cbor_build_bytestring(pk->x,
            sizeof(pk->x))) == NULL || !cbor_map_add(item, argv[3]))
                goto fail;

        /* y */
        if ((argv[4].key = cbor_build_negint8(2)) == NULL ||
            (argv[4].value = cbor_build_bytestring(pk->y,
            sizeof(pk->y))) == NULL || !cbor_map_add(item, argv[4]))
                goto fail;

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

        for (size_t i = 0; i < 5; i++) {
                if (argv[i].key)
                        cbor_decref(&argv[i].key);
                if (argv[i].value)
                        cbor_decref(&argv[i].value);
        }

        return (item);
}

es256_sk_t *
es256_sk_new(void)
{
        return (calloc(1, sizeof(es256_sk_t)));
}

void
es256_sk_free(es256_sk_t **skp)
{
        es256_sk_t *sk;

        if (skp == NULL || (sk = *skp) == NULL)
                return;

        freezero(sk, sizeof(*sk));
        *skp = NULL;
}

es256_pk_t *
es256_pk_new(void)
{
        return (calloc(1, sizeof(es256_pk_t)));
}

void
es256_pk_free(es256_pk_t **pkp)
{
        es256_pk_t *pk;

        if (pkp == NULL || (pk = *pkp) == NULL)
                return;

        freezero(pk, sizeof(*pk));
        *pkp = NULL;
}

int
es256_pk_from_ptr(es256_pk_t *pk, const void *ptr, size_t len)
{
        const uint8_t   *p = ptr;
        EVP_PKEY        *pkey;

        if (len < sizeof(*pk))
                return (FIDO_ERR_INVALID_ARGUMENT);

        if (len == sizeof(*pk) + 1 && *p == 0x04)
                memcpy(pk, ++p, sizeof(*pk)); /* uncompressed format */
        else
                memcpy(pk, ptr, sizeof(*pk)); /* libfido2 x||y format */

        if ((pkey = es256_pk_to_EVP_PKEY(pk)) == NULL) {
                fido_log_debug("%s: es256_pk_to_EVP_PKEY", __func__);
                explicit_bzero(pk, sizeof(*pk));
                return (FIDO_ERR_INVALID_ARGUMENT);
        }

        EVP_PKEY_free(pkey);

        return (FIDO_OK);
}

int
es256_pk_set_x(es256_pk_t *pk, const unsigned char *x)
{
        memcpy(pk->x, x, sizeof(pk->x));

        return (0);
}

int
es256_pk_set_y(es256_pk_t *pk, const unsigned char *y)
{
        memcpy(pk->y, y, sizeof(pk->y));

        return (0);
}

int
es256_sk_create(es256_sk_t *key)
{
        EVP_PKEY_CTX    *pctx = NULL;
        EVP_PKEY_CTX    *kctx = NULL;
        EVP_PKEY        *p = NULL;
        EVP_PKEY        *k = NULL;
        const EC_KEY    *ec;
        const BIGNUM    *d;
        int              n;
        int              ok = -1;

        if ((pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_EC, NULL)) == NULL ||
            EVP_PKEY_paramgen_init(pctx) <= 0 ||
            EVP_PKEY_CTX_set_ec_paramgen_curve_nid(pctx, es256_nid) <= 0 ||
            EVP_PKEY_paramgen(pctx, &p) <= 0) {
                fido_log_debug("%s: EVP_PKEY_paramgen", __func__);
                goto fail;
        }

        if ((kctx = EVP_PKEY_CTX_new(p, NULL)) == NULL ||
            EVP_PKEY_keygen_init(kctx) <= 0 || EVP_PKEY_keygen(kctx, &k) <= 0) {
                fido_log_debug("%s: EVP_PKEY_keygen", __func__);
                goto fail;
        }

        if ((ec = EVP_PKEY_get0_EC_KEY(k)) == NULL ||
            (d = EC_KEY_get0_private_key(ec)) == NULL ||
            (n = BN_num_bytes(d)) < 0 || (size_t)n > sizeof(key->d) ||
            (n = BN_bn2bin(d, key->d)) < 0 || (size_t)n > sizeof(key->d)) {
                fido_log_debug("%s: EC_KEY_get0_private_key", __func__);
                goto fail;
        }

        ok = 0;
fail:
        if (p != NULL)
                EVP_PKEY_free(p);
        if (k != NULL)
                EVP_PKEY_free(k);
        if (pctx != NULL)
                EVP_PKEY_CTX_free(pctx);
        if (kctx != NULL)
                EVP_PKEY_CTX_free(kctx);

        return (ok);
}

EVP_PKEY *
es256_pk_to_EVP_PKEY(const es256_pk_t *k)
{
        BN_CTX          *bnctx = NULL;
        EC_KEY          *ec = NULL;
        EC_POINT        *q = NULL;
        EVP_PKEY        *pkey = NULL;
        BIGNUM          *x = NULL;
        BIGNUM          *y = NULL;
        const EC_GROUP  *g = NULL;
        int              ok = -1;

        if ((bnctx = BN_CTX_new()) == NULL)
                goto fail;

        BN_CTX_start(bnctx);

        if ((x = BN_CTX_get(bnctx)) == NULL ||
            (y = BN_CTX_get(bnctx)) == NULL)
                goto fail;

        if (BN_bin2bn(k->x, sizeof(k->x), x) == NULL ||
            BN_bin2bn(k->y, sizeof(k->y), y) == NULL) {
                fido_log_debug("%s: BN_bin2bn", __func__);
                goto fail;
        }

        if ((ec = EC_KEY_new_by_curve_name(es256_nid)) == NULL ||
            (g = EC_KEY_get0_group(ec)) == NULL) {
                fido_log_debug("%s: EC_KEY init", __func__);
                goto fail;
        }

        if ((q = EC_POINT_new(g)) == NULL ||
            EC_POINT_set_affine_coordinates_GFp(g, q, x, y, bnctx) == 0 ||
            EC_KEY_set_public_key(ec, q) == 0) {
                fido_log_debug("%s: EC_KEY_set_public_key", __func__);
                goto fail;
        }

        if ((pkey = EVP_PKEY_new()) == NULL ||
            EVP_PKEY_assign_EC_KEY(pkey, ec) == 0) {
                fido_log_debug("%s: EVP_PKEY_assign_EC_KEY", __func__);
                goto fail;
        }

        ec = NULL; /* at this point, ec belongs to evp */

        ok = 0;
fail:
        if (bnctx != NULL) {
                BN_CTX_end(bnctx);
                BN_CTX_free(bnctx);
        }

        if (ec != NULL)
                EC_KEY_free(ec);
        if (q != NULL)
                EC_POINT_free(q);

        if (ok < 0 && pkey != NULL) {
                EVP_PKEY_free(pkey);
                pkey = NULL;
        }

        return (pkey);
}

int
es256_pk_from_EC_KEY(es256_pk_t *pk, const EC_KEY *ec)
{
        BN_CTX          *bnctx = NULL;
        BIGNUM          *x = NULL;
        BIGNUM          *y = NULL;
        const EC_POINT  *q = NULL;
        EC_GROUP        *g = NULL;
        size_t           dx;
        size_t           dy;
        int              ok = FIDO_ERR_INTERNAL;
        int              nx;
        int              ny;

        if ((q = EC_KEY_get0_public_key(ec)) == NULL ||
            (g = EC_GROUP_new_by_curve_name(es256_nid)) == NULL ||
            (bnctx = BN_CTX_new()) == NULL)
                goto fail;

        BN_CTX_start(bnctx);

        if ((x = BN_CTX_get(bnctx)) == NULL ||
            (y = BN_CTX_get(bnctx)) == NULL)
                goto fail;

        if (EC_POINT_is_on_curve(g, q, bnctx) != 1) {
                fido_log_debug("%s: EC_POINT_is_on_curve", __func__);
                ok = FIDO_ERR_INVALID_ARGUMENT;
                goto fail;
        }

        if (EC_POINT_get_affine_coordinates_GFp(g, q, x, y, bnctx) == 0 ||
            (nx = BN_num_bytes(x)) < 0 || (size_t)nx > sizeof(pk->x) ||
            (ny = BN_num_bytes(y)) < 0 || (size_t)ny > sizeof(pk->y)) {
                fido_log_debug("%s: EC_POINT_get_affine_coordinates_GFp",
                    __func__);
                goto fail;
        }

        dx = sizeof(pk->x) - (size_t)nx;
        dy = sizeof(pk->y) - (size_t)ny;

        if ((nx = BN_bn2bin(x, pk->x + dx)) < 0 || (size_t)nx > sizeof(pk->x) ||
            (ny = BN_bn2bin(y, pk->y + dy)) < 0 || (size_t)ny > sizeof(pk->y)) {
                fido_log_debug("%s: BN_bn2bin", __func__);
                goto fail;
        }

        ok = FIDO_OK;
fail:
        EC_GROUP_free(g);

        if (bnctx != NULL) {
                BN_CTX_end(bnctx);
                BN_CTX_free(bnctx);
        }

        return (ok);
}

int
es256_pk_from_EVP_PKEY(es256_pk_t *pk, const EVP_PKEY *pkey)
{
        const EC_KEY *ec;

        if (EVP_PKEY_base_id(pkey) != EVP_PKEY_EC ||
            (ec = get0_EC_KEY(pkey)) == NULL)
                return (FIDO_ERR_INVALID_ARGUMENT);

        return (es256_pk_from_EC_KEY(pk, ec));
}

EVP_PKEY *
es256_sk_to_EVP_PKEY(const es256_sk_t *k)
{
        BN_CTX          *bnctx = NULL;
        EC_KEY          *ec = NULL;
        EVP_PKEY        *pkey = NULL;
        BIGNUM          *d = NULL;
        int              ok = -1;

        if ((bnctx = BN_CTX_new()) == NULL)
                goto fail;

        BN_CTX_start(bnctx);

        if ((d = BN_CTX_get(bnctx)) == NULL ||
            BN_bin2bn(k->d, sizeof(k->d), d) == NULL) {
                fido_log_debug("%s: BN_bin2bn", __func__);
                goto fail;
        }

        if ((ec = EC_KEY_new_by_curve_name(es256_nid)) == NULL ||
            EC_KEY_set_private_key(ec, d) == 0) {
                fido_log_debug("%s: EC_KEY_set_private_key", __func__);
                goto fail;
        }

        if ((pkey = EVP_PKEY_new()) == NULL ||
            EVP_PKEY_assign_EC_KEY(pkey, ec) == 0) {
                fido_log_debug("%s: EVP_PKEY_assign_EC_KEY", __func__);
                goto fail;
        }

        ec = NULL; /* at this point, ec belongs to evp */

        ok = 0;
fail:
        if (bnctx != NULL) {
                BN_CTX_end(bnctx);
                BN_CTX_free(bnctx);
        }

        if (ec != NULL)
                EC_KEY_free(ec);

        if (ok < 0 && pkey != NULL) {
                EVP_PKEY_free(pkey);
                pkey = NULL;
        }

        return (pkey);
}

int
es256_derive_pk(const es256_sk_t *sk, es256_pk_t *pk)
{
        BIGNUM          *d = NULL;
        EC_KEY          *ec = NULL;
        EC_POINT        *q = NULL;
        const EC_GROUP  *g = NULL;
        int              ok = -1;

        if ((d = BN_bin2bn(sk->d, (int)sizeof(sk->d), NULL)) == NULL ||
            (ec = EC_KEY_new_by_curve_name(es256_nid)) == NULL ||
            (g = EC_KEY_get0_group(ec)) == NULL ||
            (q = EC_POINT_new(g)) == NULL) {
                fido_log_debug("%s: get", __func__);
                goto fail;
        }

        if (EC_POINT_mul(g, q, d, NULL, NULL, NULL) == 0 ||
            EC_KEY_set_public_key(ec, q) == 0 ||
            es256_pk_from_EC_KEY(pk, ec) != FIDO_OK) {
                fido_log_debug("%s: set", __func__);
                goto fail;
        }

        ok = 0;
fail:
        if (d != NULL)
                BN_clear_free(d);
        if (q != NULL)
                EC_POINT_free(q);
        if (ec != NULL)
                EC_KEY_free(ec);

        return (ok);
}

int
es256_verify_sig(const fido_blob_t *dgst, EVP_PKEY *pkey,
    const fido_blob_t *sig)
{
        EVP_PKEY_CTX    *pctx = NULL;
        int              ok = -1;

        if (EVP_PKEY_base_id(pkey) != EVP_PKEY_EC) {
                fido_log_debug("%s: EVP_PKEY_base_id", __func__);
                goto fail;
        }

        if ((pctx = EVP_PKEY_CTX_new(pkey, NULL)) == NULL ||
            EVP_PKEY_verify_init(pctx) != 1 ||
            EVP_PKEY_verify(pctx, sig->ptr, sig->len, dgst->ptr,
            dgst->len) != 1) {
                fido_log_debug("%s: EVP_PKEY_verify", __func__);
                goto fail;
        }

        ok = 0;
fail:
        EVP_PKEY_CTX_free(pctx);

        return (ok);
}

int
es256_pk_verify_sig(const fido_blob_t *dgst, const es256_pk_t *pk,
    const fido_blob_t *sig)
{
        EVP_PKEY        *pkey;
        int              ok = -1;

        if ((pkey = es256_pk_to_EVP_PKEY(pk)) == NULL ||
            es256_verify_sig(dgst, pkey, sig) < 0) {
                fido_log_debug("%s: es256_verify_sig", __func__);
                goto fail;
        }

        ok = 0;
fail:
        EVP_PKEY_free(pkey);

        return (ok);
}

Coverage Report

Created: 2026-04-08 06:32

Line	Count	Source
1		/*
2		* Copyright (c) 2018-2022 Yubico AB. All rights reserved.
3		* Use of this source code is governed by a BSD-style
4		* license that can be found in the LICENSE file.
5		* SPDX-License-Identifier: BSD-2-Clause
6		*/
7
8		#include <openssl/bn.h>
9		#include <openssl/ecdsa.h>
10		#include <openssl/obj_mac.h>
11
12		#include "fido.h"
13		#include "fido/es256.h"
14
15		#if OPENSSL_VERSION_NUMBER >= 0x30000000
16	321	#define get0_EC_KEY(x) EVP_PKEY_get0_EC_KEY((x))
17		#else
18		#define get0_EC_KEY(x) EVP_PKEY_get0((x))
19		#endif
20
21		static const int es256_nid = NID_X9_62_prime256v1;
22
23		static int
24		decode_coord(const cbor_item_t item, void xy, size_t xy_len)
25	98.2k	{
26	98.2k	if (cbor_isa_bytestring(item) == false \|\|
27	98.2k	cbor_bytestring_is_definite(item) == false \|\|
28	98.2k	cbor_bytestring_length(item) != xy_len) {
29	767	fido_log_debug("%s: cbor type", __func__);
30	767	return (-1);
31	767	}
32
33	97.4k	memcpy(xy, cbor_bytestring_handle(item), xy_len);
34
35	97.4k	return (0);
36	98.2k	}
37
38		static int
39		decode_pubkey_point(const cbor_item_t key, const cbor_item_t val, void *arg)
40	253k	{
41	253k	es256_pk_t *k = arg;
42
43	253k	if (cbor_isa_negint(key) == false \|\|
44	253k	cbor_int_get_width(key) != CBOR_INT_8)
45	117k	return (0); /* ignore */
46
47	135k	switch (cbor_get_uint8(key)) {
48	50.1k	case 1: /* x coordinate */
49	50.1k	return (decode_coord(val, &k->x, sizeof(k->x)));
50	48.0k	case 2: /* y coordinate */
51	48.0k	return (decode_coord(val, &k->y, sizeof(k->y)));
52	135k	}
53
54	37.5k	return (0); /* ignore */
55	135k	}
56
57		int
58		es256_pk_decode(const cbor_item_t item, es256_pk_t k)
59	53.3k	{
60	53.3k	if (cbor_isa_map(item) == false \|\|
61	53.3k	cbor_map_is_definite(item) == false \|\|
62	53.3k	cbor_map_iter(item, k, decode_pubkey_point) < 0) {
63	3.24k	fido_log_debug("%s: cbor type", __func__);
64	3.24k	return (-1);
65	3.24k	}
66
67	50.1k	return (0);
68	53.3k	}
69
70		cbor_item_t *
71		es256_pk_encode(const es256_pk_t *pk, int ecdh)
72	23.4k	{
73	23.4k	cbor_item_t *item = NULL;
74	23.4k	struct cbor_pair argv[5];
75	23.4k	int alg;
76	23.4k	int ok = -1;
77
78	23.4k	memset(argv, 0, sizeof(argv));
79
80	23.4k	if ((item = cbor_new_definite_map(5)) == NULL)
81	119	goto fail;
82
83		/* kty */
84	23.3k	if ((argv[0].key = cbor_build_uint8(1)) == NULL \|\|
85	23.3k	(argv[0].value = cbor_build_uint8(2)) == NULL \|\|
86	23.3k	!cbor_map_add(item, argv[0]))
87	402	goto fail;
88
89		/*
90		* "The COSEAlgorithmIdentifier used is -25 (ECDH-ES +
91		* HKDF-256) although this is NOT the algorithm actually
92		* used. Setting this to a different value may result in
93		* compatibility issues."
94		*/
95	22.9k	if (ecdh)
96	22.3k	alg = COSE_ECDH_ES256;
97	559	else
98	559	alg = COSE_ES256;
99
100		/* alg */
101	22.9k	if ((argv[1].key = cbor_build_uint8(3)) == NULL \|\|
102	22.9k	(argv[1].value = cbor_build_negint8((uint8_t)(-alg - 1))) == NULL \|\|
103	22.9k	!cbor_map_add(item, argv[1]))
104	282	goto fail;
105
106		/* crv */
107	22.6k	if ((argv[2].key = cbor_build_negint8(0)) == NULL \|\|
108	22.6k	(argv[2].value = cbor_build_uint8(1)) == NULL \|\|
109	22.6k	!cbor_map_add(item, argv[2]))
110	291	goto fail;
111
112		/* x */
113	22.3k	if ((argv[3].key = cbor_build_negint8(1)) == NULL \|\|
114	22.3k	(argv[3].value = cbor_build_bytestring(pk->x,
115	22.2k	sizeof(pk->x))) == NULL \|\| !cbor_map_add(item, argv[3]))
116	331	goto fail;
117
118		/* y */
119	22.0k	if ((argv[4].key = cbor_build_negint8(2)) == NULL \|\|
120	22.0k	(argv[4].value = cbor_build_bytestring(pk->y,
121	21.8k	sizeof(pk->y))) == NULL \|\| !cbor_map_add(item, argv[4]))
122	279	goto fail;
123
124	21.7k	ok = 0;
125	23.4k	fail:
126	23.4k	if (ok < 0) {
127	1.70k	if (item != NULL) {
128	1.58k	cbor_decref(&item);
129	1.58k	item = NULL;
130	1.58k	}
131	1.70k	}
132
133	140k	for (size_t i = 0; i < 5; i++) {
134	117k	if (argv[i].key)
135	112k	cbor_decref(&argv[i].key);
136	117k	if (argv[i].value)
137	112k	cbor_decref(&argv[i].value);
138	117k	}
139
140	23.4k	return (item);
141	21.7k	}
142
143		es256_sk_t *
144		es256_sk_new(void)
145	117k	{
146	117k	return (calloc(1, sizeof(es256_sk_t)));
147	117k	}
148
149		void
150		es256_sk_free(es256_sk_t **skp)
151	117k	{
152	117k	es256_sk_t *sk;
153
154	117k	if (skp == NULL \|\| (sk = *skp) == NULL)
155	296	return;
156
157	117k	freezero(sk, sizeof(*sk));
158	117k	*skp = NULL;
159	117k	}
160
161		es256_pk_t *
162		es256_pk_new(void)
163	234k	{
164	234k	return (calloc(1, sizeof(es256_pk_t)));
165	234k	}
166
167		void
168		es256_pk_free(es256_pk_t **pkp)
169	423k	{
170	423k	es256_pk_t *pk;
171
172	423k	if (pkp == NULL \|\| (pk = *pkp) == NULL)
173	189k	return;
174
175	234k	freezero(pk, sizeof(*pk));
176	234k	*pkp = NULL;
177	234k	}
178
179		int
180		es256_pk_from_ptr(es256_pk_t pk, const void ptr, size_t len)
181	6.48k	{
182	6.48k	const uint8_t *p = ptr;
183	6.48k	EVP_PKEY *pkey;
184
185	6.48k	if (len < sizeof(*pk))
186	3.82k	return (FIDO_ERR_INVALID_ARGUMENT);
187
188	2.65k	if (len == sizeof(pk) + 1 && p == 0x04)
189	255	memcpy(pk, ++p, sizeof(pk)); / uncompressed format */
190	2.39k	else
191	2.39k	memcpy(pk, ptr, sizeof(pk)); / libfido2 x\|\|y format */
192
193	2.65k	if ((pkey = es256_pk_to_EVP_PKEY(pk)) == NULL) {
194	2.31k	fido_log_debug("%s: es256_pk_to_EVP_PKEY", __func__);
195	2.31k	explicit_bzero(pk, sizeof(*pk));
196	2.31k	return (FIDO_ERR_INVALID_ARGUMENT);
197	2.31k	}
198
199	335	EVP_PKEY_free(pkey);
200
201	335	return (FIDO_OK);
202	2.65k	}
203
204		int
205		es256_pk_set_x(es256_pk_t pk, const unsigned char x)
206	559	{
207	559	memcpy(pk->x, x, sizeof(pk->x));
208
209	559	return (0);
210	559	}
211
212		int
213		es256_pk_set_y(es256_pk_t pk, const unsigned char y)
214	559	{
215	559	memcpy(pk->y, y, sizeof(pk->y));
216
217	559	return (0);
218	559	}
219
220		int
221		es256_sk_create(es256_sk_t *key)
222	117k	{
223	117k	EVP_PKEY_CTX *pctx = NULL;
224	117k	EVP_PKEY_CTX *kctx = NULL;
225	117k	EVP_PKEY *p = NULL;
226	117k	EVP_PKEY *k = NULL;
227	117k	const EC_KEY *ec;
228	117k	const BIGNUM *d;
229	117k	int n;
230	117k	int ok = -1;
231
232	117k	if ((pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_EC, NULL)) == NULL \|\|
233	117k	EVP_PKEY_paramgen_init(pctx) <= 0 \|\|
234	117k	EVP_PKEY_CTX_set_ec_paramgen_curve_nid(pctx, es256_nid) <= 0 \|\|
235	117k	EVP_PKEY_paramgen(pctx, &p) <= 0) {
236	1.04k	fido_log_debug("%s: EVP_PKEY_paramgen", __func__);
237	1.04k	goto fail;
238	1.04k	}
239
240	116k	if ((kctx = EVP_PKEY_CTX_new(p, NULL)) == NULL \|\|
241	116k	EVP_PKEY_keygen_init(kctx) <= 0 \|\| EVP_PKEY_keygen(kctx, &k) <= 0) {
242	1.03k	fido_log_debug("%s: EVP_PKEY_keygen", __func__);
243	1.03k	goto fail;
244	1.03k	}
245
246	115k	if ((ec = EVP_PKEY_get0_EC_KEY(k)) == NULL \|\|
247	115k	(d = EC_KEY_get0_private_key(ec)) == NULL \|\|
248	115k	(n = BN_num_bytes(d)) < 0 \|\| (size_t)n > sizeof(key->d) \|\|
249	115k	(n = BN_bn2bin(d, key->d)) < 0 \|\| (size_t)n > sizeof(key->d)) {
250	1.17k	fido_log_debug("%s: EC_KEY_get0_private_key", __func__);
251	1.17k	goto fail;
252	1.17k	}
253
254	113k	ok = 0;
255	117k	fail:
256	117k	if (p != NULL)
257	116k	EVP_PKEY_free(p);
258	117k	if (k != NULL)
259	115k	EVP_PKEY_free(k);
260	117k	if (pctx != NULL)
261	116k	EVP_PKEY_CTX_free(pctx);
262	117k	if (kctx != NULL)
263	115k	EVP_PKEY_CTX_free(kctx);
264
265	117k	return (ok);
266	113k	}
267
268		EVP_PKEY *
269		es256_pk_to_EVP_PKEY(const es256_pk_t *k)
270	45.5k	{
271	45.5k	BN_CTX *bnctx = NULL;
272	45.5k	EC_KEY *ec = NULL;
273	45.5k	EC_POINT *q = NULL;
274	45.5k	EVP_PKEY *pkey = NULL;
275	45.5k	BIGNUM *x = NULL;
276	45.5k	BIGNUM *y = NULL;
277	45.5k	const EC_GROUP *g = NULL;
278	45.5k	int ok = -1;
279
280	45.5k	if ((bnctx = BN_CTX_new()) == NULL)
281	171	goto fail;
282
283	45.3k	BN_CTX_start(bnctx);
284
285	45.3k	if ((x = BN_CTX_get(bnctx)) == NULL \|\|
286	45.3k	(y = BN_CTX_get(bnctx)) == NULL)
287	362	goto fail;
288
289	44.9k	if (BN_bin2bn(k->x, sizeof(k->x), x) == NULL \|\|
290	44.9k	BN_bin2bn(k->y, sizeof(k->y), y) == NULL) {
291	597	fido_log_debug("%s: BN_bin2bn", __func__);
292	597	goto fail;
293	597	}
294
295	44.3k	if ((ec = EC_KEY_new_by_curve_name(es256_nid)) == NULL \|\|
296	44.3k	(g = EC_KEY_get0_group(ec)) == NULL) {
297	211	fido_log_debug("%s: EC_KEY init", __func__);
298	211	goto fail;
299	211	}
300
301	44.1k	if ((q = EC_POINT_new(g)) == NULL \|\|
302	44.1k	EC_POINT_set_affine_coordinates_GFp(g, q, x, y, bnctx) == 0 \|\|
303	44.1k	EC_KEY_set_public_key(ec, q) == 0) {
304	12.0k	fido_log_debug("%s: EC_KEY_set_public_key", __func__);
305	12.0k	goto fail;
306	12.0k	}
307
308	32.1k	if ((pkey = EVP_PKEY_new()) == NULL \|\|
309	32.1k	EVP_PKEY_assign_EC_KEY(pkey, ec) == 0) {
310	235	fido_log_debug("%s: EVP_PKEY_assign_EC_KEY", __func__);
311	235	goto fail;
312	235	}
313
314	31.8k	ec = NULL; /* at this point, ec belongs to evp */
315
316	31.8k	ok = 0;
317	45.5k	fail:
318	45.5k	if (bnctx != NULL) {
319	45.3k	BN_CTX_end(bnctx);
320	45.3k	BN_CTX_free(bnctx);
321	45.3k	}
322
323	45.5k	if (ec != NULL)
324	12.3k	EC_KEY_free(ec);
325	45.5k	if (q != NULL)
326	44.0k	EC_POINT_free(q);
327
328	45.5k	if (ok < 0 && pkey != NULL) {
329	131	EVP_PKEY_free(pkey);
330	131	pkey = NULL;
331	131	}
332
333	45.5k	return (pkey);
334	31.8k	}
335
336		int
337		es256_pk_from_EC_KEY(es256_pk_t pk, const EC_KEY ec)
338	112k	{
339	112k	BN_CTX *bnctx = NULL;
340	112k	BIGNUM *x = NULL;
341	112k	BIGNUM *y = NULL;
342	112k	const EC_POINT *q = NULL;
343	112k	EC_GROUP *g = NULL;
344	112k	size_t dx;
345	112k	size_t dy;
346	112k	int ok = FIDO_ERR_INTERNAL;
347	112k	int nx;
348	112k	int ny;
349
350	112k	if ((q = EC_KEY_get0_public_key(ec)) == NULL \|\|
351	112k	(g = EC_GROUP_new_by_curve_name(es256_nid)) == NULL \|\|
352	112k	(bnctx = BN_CTX_new()) == NULL)
353	383	goto fail;
354
355	112k	BN_CTX_start(bnctx);
356
357	112k	if ((x = BN_CTX_get(bnctx)) == NULL \|\|
358	112k	(y = BN_CTX_get(bnctx)) == NULL)
359	914	goto fail;
360
361	111k	if (EC_POINT_is_on_curve(g, q, bnctx) != 1) {
362	0	fido_log_debug("%s: EC_POINT_is_on_curve", __func__);
363	0	ok = FIDO_ERR_INVALID_ARGUMENT;
364	0	goto fail;
365	0	}
366
367	111k	if (EC_POINT_get_affine_coordinates_GFp(g, q, x, y, bnctx) == 0 \|\|
368	111k	(nx = BN_num_bytes(x)) < 0 \|\| (size_t)nx > sizeof(pk->x) \|\|
369	111k	(ny = BN_num_bytes(y)) < 0 \|\| (size_t)ny > sizeof(pk->y)) {
370	350	fido_log_debug("%s: EC_POINT_get_affine_coordinates_GFp",
371	350	__func__);
372	350	goto fail;
373	350	}
374
375	110k	dx = sizeof(pk->x) - (size_t)nx;
376	110k	dy = sizeof(pk->y) - (size_t)ny;
377
378	110k	if ((nx = BN_bn2bin(x, pk->x + dx)) < 0 \|\| (size_t)nx > sizeof(pk->x) \|\|
379	110k	(ny = BN_bn2bin(y, pk->y + dy)) < 0 \|\| (size_t)ny > sizeof(pk->y)) {
380	618	fido_log_debug("%s: BN_bn2bin", __func__);
381	618	goto fail;
382	618	}
383
384	110k	ok = FIDO_OK;
385	112k	fail:
386	112k	EC_GROUP_free(g);
387
388	112k	if (bnctx != NULL) {
389	112k	BN_CTX_end(bnctx);
390	112k	BN_CTX_free(bnctx);
391	112k	}
392
393	112k	return (ok);
394	110k	}
395
396		int
397		es256_pk_from_EVP_PKEY(es256_pk_t pk, const EVP_PKEY pkey)
398	321	{
399	321	const EC_KEY *ec;
400
401	321	if (EVP_PKEY_base_id(pkey) != EVP_PKEY_EC \|\|
402	321	(ec = get0_EC_KEY(pkey)) == NULL)
403	9	return (FIDO_ERR_INVALID_ARGUMENT);
404
405	312	return (es256_pk_from_EC_KEY(pk, ec));
406	321	}
407
408		EVP_PKEY *
409		es256_sk_to_EVP_PKEY(const es256_sk_t *k)
410	31.0k	{
411	31.0k	BN_CTX *bnctx = NULL;
412	31.0k	EC_KEY *ec = NULL;
413	31.0k	EVP_PKEY *pkey = NULL;
414	31.0k	BIGNUM *d = NULL;
415	31.0k	int ok = -1;
416
417	31.0k	if ((bnctx = BN_CTX_new()) == NULL)
418	67	goto fail;
419
420	30.9k	BN_CTX_start(bnctx);
421
422	30.9k	if ((d = BN_CTX_get(bnctx)) == NULL \|\|
423	30.9k	BN_bin2bn(k->d, sizeof(k->d), d) == NULL) {
424	154	fido_log_debug("%s: BN_bin2bn", __func__);
425	154	goto fail;
426	154	}
427
428	30.7k	if ((ec = EC_KEY_new_by_curve_name(es256_nid)) == NULL \|\|
429	30.7k	EC_KEY_set_private_key(ec, d) == 0) {
430	67	fido_log_debug("%s: EC_KEY_set_private_key", __func__);
431	67	goto fail;
432	67	}
433
434	30.7k	if ((pkey = EVP_PKEY_new()) == NULL \|\|
435	30.7k	EVP_PKEY_assign_EC_KEY(pkey, ec) == 0) {
436	232	fido_log_debug("%s: EVP_PKEY_assign_EC_KEY", __func__);
437	232	goto fail;
438	232	}
439
440	30.4k	ec = NULL; /* at this point, ec belongs to evp */
441
442	30.4k	ok = 0;
443	31.0k	fail:
444	31.0k	if (bnctx != NULL) {
445	30.9k	BN_CTX_end(bnctx);
446	30.9k	BN_CTX_free(bnctx);
447	30.9k	}
448
449	31.0k	if (ec != NULL)
450	232	EC_KEY_free(ec);
451
452	31.0k	if (ok < 0 && pkey != NULL) {
453	173	EVP_PKEY_free(pkey);
454	173	pkey = NULL;
455	173	}
456
457	31.0k	return (pkey);
458	30.4k	}
459
460		int
461		es256_derive_pk(const es256_sk_t sk, es256_pk_t pk)
462	113k	{
463	113k	BIGNUM *d = NULL;
464	113k	EC_KEY *ec = NULL;
465	113k	EC_POINT *q = NULL;
466	113k	const EC_GROUP *g = NULL;
467	113k	int ok = -1;
468
469	113k	if ((d = BN_bin2bn(sk->d, (int)sizeof(sk->d), NULL)) == NULL \|\|
470	113k	(ec = EC_KEY_new_by_curve_name(es256_nid)) == NULL \|\|
471	113k	(g = EC_KEY_get0_group(ec)) == NULL \|\|
472	113k	(q = EC_POINT_new(g)) == NULL) {
473	1.73k	fido_log_debug("%s: get", __func__);
474	1.73k	goto fail;
475	1.73k	}
476
477	112k	if (EC_POINT_mul(g, q, d, NULL, NULL, NULL) == 0 \|\|
478	112k	EC_KEY_set_public_key(ec, q) == 0 \|\|
479	112k	es256_pk_from_EC_KEY(pk, ec) != FIDO_OK) {
480	2.20k	fido_log_debug("%s: set", __func__);
481	2.20k	goto fail;
482	2.20k	}
483
484	109k	ok = 0;
485	113k	fail:
486	113k	if (d != NULL)
487	113k	BN_clear_free(d);
488	113k	if (q != NULL)
489	112k	EC_POINT_free(q);
490	113k	if (ec != NULL)
491	112k	EC_KEY_free(ec);
492
493	113k	return (ok);
494	109k	}
495
496		int
497		es256_verify_sig(const fido_blob_t dgst, EVP_PKEY pkey,
498		const fido_blob_t *sig)
499	3.94k	{
500	3.94k	EVP_PKEY_CTX *pctx = NULL;
501	3.94k	int ok = -1;
502
503	3.94k	if (EVP_PKEY_base_id(pkey) != EVP_PKEY_EC) {
504	8	fido_log_debug("%s: EVP_PKEY_base_id", __func__);
505	8	goto fail;
506	8	}
507
508	3.94k	if ((pctx = EVP_PKEY_CTX_new(pkey, NULL)) == NULL \|\|
509	3.94k	EVP_PKEY_verify_init(pctx) != 1 \|\|
510	3.94k	EVP_PKEY_verify(pctx, sig->ptr, sig->len, dgst->ptr,
511	3.94k	dgst->len) != 1) {
512	3.94k	fido_log_debug("%s: EVP_PKEY_verify", __func__);
513	3.94k	goto fail;
514	3.94k	}
515
516	0	ok = 0;
517	3.94k	fail:
518	3.94k	EVP_PKEY_CTX_free(pctx);
519
520	3.94k	return (ok);
521	0	}
522
523		int
524		es256_pk_verify_sig(const fido_blob_t dgst, const es256_pk_t pk,
525		const fido_blob_t *sig)
526	310	{
527	310	EVP_PKEY *pkey;
528	310	int ok = -1;
529
530	310	if ((pkey = es256_pk_to_EVP_PKEY(pk)) == NULL \|\|
531	310	es256_verify_sig(dgst, pkey, sig) < 0) {
532	310	fido_log_debug("%s: es256_verify_sig", __func__);
533	310	goto fail;
534	310	}
535
536	0	ok = 0;
537	310	fail:
538	310	EVP_PKEY_free(pkey);
539
540	310	return (ok);
541	0	}