/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: 2025-10-04 18:33

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	311	#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	71.7k	{
26	71.7k	if (cbor_isa_bytestring(item) == false \|\|
27	71.7k	cbor_bytestring_is_definite(item) == false \|\|
28	71.7k	cbor_bytestring_length(item) != xy_len) {
29	543	fido_log_debug("%s: cbor type", __func__);
30	543	return (-1);
31	543	}
32
33	71.2k	memcpy(xy, cbor_bytestring_handle(item), xy_len);
34
35	71.2k	return (0);
36	71.7k	}
37
38		static int
39		decode_pubkey_point(const cbor_item_t key, const cbor_item_t val, void *arg)
40	184k	{
41	184k	es256_pk_t *k = arg;
42
43	184k	if (cbor_isa_negint(key) == false \|\|
44	184k	cbor_int_get_width(key) != CBOR_INT_8)
45	86.4k	return (0); /* ignore */
46
47	97.7k	switch (cbor_get_uint8(key)) {
48	36.5k	case 1: /* x coordinate */
49	36.5k	return (decode_coord(val, &k->x, sizeof(k->x)));
50	35.2k	case 2: /* y coordinate */
51	35.2k	return (decode_coord(val, &k->y, sizeof(k->y)));
52	97.7k	}
53
54	25.9k	return (0); /* ignore */
55	97.7k	}
56
57		int
58		es256_pk_decode(const cbor_item_t item, es256_pk_t k)
59	37.5k	{
60	37.5k	if (cbor_isa_map(item) == false \|\|
61	37.5k	cbor_map_is_definite(item) == false \|\|
62	37.5k	cbor_map_iter(item, k, decode_pubkey_point) < 0) {
63	1.21k	fido_log_debug("%s: cbor type", __func__);
64	1.21k	return (-1);
65	1.21k	}
66
67	36.3k	return (0);
68	37.5k	}
69
70		cbor_item_t *
71		es256_pk_encode(const es256_pk_t *pk, int ecdh)
72	16.6k	{
73	16.6k	cbor_item_t *item = NULL;
74	16.6k	struct cbor_pair argv[5];
75	16.6k	int alg;
76	16.6k	int ok = -1;
77
78	16.6k	memset(argv, 0, sizeof(argv));
79
80	16.6k	if ((item = cbor_new_definite_map(5)) == NULL)
81	71	goto fail;
82
83		/* kty */
84	16.5k	if ((argv[0].key = cbor_build_uint8(1)) == NULL \|\|
85	16.5k	(argv[0].value = cbor_build_uint8(2)) == NULL \|\|
86	16.5k	!cbor_map_add(item, argv[0]))
87	339	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	16.2k	if (ecdh)
96	15.5k	alg = COSE_ECDH_ES256;
97	661	else
98	661	alg = COSE_ES256;
99
100		/* alg */
101	16.2k	if ((argv[1].key = cbor_build_uint8(3)) == NULL \|\|
102	16.2k	(argv[1].value = cbor_build_negint8((uint8_t)(-alg - 1))) == NULL \|\|
103	16.2k	!cbor_map_add(item, argv[1]))
104	340	goto fail;
105
106		/* crv */
107	15.9k	if ((argv[2].key = cbor_build_negint8(0)) == NULL \|\|
108	15.9k	(argv[2].value = cbor_build_uint8(1)) == NULL \|\|
109	15.9k	!cbor_map_add(item, argv[2]))
110	225	goto fail;
111
112		/* x */
113	15.6k	if ((argv[3].key = cbor_build_negint8(1)) == NULL \|\|
114	15.6k	(argv[3].value = cbor_build_bytestring(pk->x,
115	15.6k	sizeof(pk->x))) == NULL \|\| !cbor_map_add(item, argv[3]))
116	220	goto fail;
117
118		/* y */
119	15.4k	if ((argv[4].key = cbor_build_negint8(2)) == NULL \|\|
120	15.4k	(argv[4].value = cbor_build_bytestring(pk->y,
121	15.4k	sizeof(pk->y))) == NULL \|\| !cbor_map_add(item, argv[4]))
122	244	goto fail;
123
124	15.2k	ok = 0;
125	16.6k	fail:
126	16.6k	if (ok < 0) {
127	1.43k	if (item != NULL) {
128	1.36k	cbor_decref(&item);
129	1.36k	item = NULL;
130	1.36k	}
131	1.43k	}
132
133	99.9k	for (size_t i = 0; i < 5; i++) {
134	83.2k	if (argv[i].key)
135	79.2k	cbor_decref(&argv[i].key);
136	83.2k	if (argv[i].value)
137	78.8k	cbor_decref(&argv[i].value);
138	83.2k	}
139
140	16.6k	return (item);
141	15.2k	}
142
143		es256_sk_t *
144		es256_sk_new(void)
145	50.0k	{
146	50.0k	return (calloc(1, sizeof(es256_sk_t)));
147	50.0k	}
148
149		void
150		es256_sk_free(es256_sk_t **skp)
151	50.0k	{
152	50.0k	es256_sk_t *sk;
153
154	50.0k	if (skp == NULL \|\| (sk = *skp) == NULL)
155	151	return;
156
157	49.9k	freezero(sk, sizeof(*sk));
158	49.9k	*skp = NULL;
159	49.9k	}
160
161		es256_pk_t *
162		es256_pk_new(void)
163	100k	{
164	100k	return (calloc(1, sizeof(es256_pk_t)));
165	100k	}
166
167		void
168		es256_pk_free(es256_pk_t **pkp)
169	191k	{
170	191k	es256_pk_t *pk;
171
172	191k	if (pkp == NULL \|\| (pk = *pkp) == NULL)
173	91.4k	return;
174
175	99.8k	freezero(pk, sizeof(*pk));
176	99.8k	*pkp = NULL;
177	99.8k	}
178
179		int
180		es256_pk_from_ptr(es256_pk_t pk, const void ptr, size_t len)
181	5.07k	{
182	5.07k	const uint8_t *p = ptr;
183	5.07k	EVP_PKEY *pkey;
184
185	5.07k	if (len < sizeof(*pk))
186	3.08k	return (FIDO_ERR_INVALID_ARGUMENT);
187
188	1.99k	if (len == sizeof(pk) + 1 && p == 0x04)
189	7	memcpy(pk, ++p, sizeof(pk)); / uncompressed format */
190	1.98k	else
191	1.98k	memcpy(pk, ptr, sizeof(pk)); / libfido2 x\|\|y format */
192
193	1.99k	if ((pkey = es256_pk_to_EVP_PKEY(pk)) == NULL) {
194	1.66k	fido_log_debug("%s: es256_pk_to_EVP_PKEY", __func__);
195	1.66k	explicit_bzero(pk, sizeof(*pk));
196	1.66k	return (FIDO_ERR_INVALID_ARGUMENT);
197	1.66k	}
198
199	324	EVP_PKEY_free(pkey);
200
201	324	return (FIDO_OK);
202	1.99k	}
203
204		int
205		es256_pk_set_x(es256_pk_t pk, const unsigned char x)
206	662	{
207	662	memcpy(pk->x, x, sizeof(pk->x));
208
209	662	return (0);
210	662	}
211
212		int
213		es256_pk_set_y(es256_pk_t pk, const unsigned char y)
214	662	{
215	662	memcpy(pk->y, y, sizeof(pk->y));
216
217	662	return (0);
218	662	}
219
220		int
221		es256_sk_create(es256_sk_t *key)
222	49.7k	{
223	49.7k	EVP_PKEY_CTX *pctx = NULL;
224	49.7k	EVP_PKEY_CTX *kctx = NULL;
225	49.7k	EVP_PKEY *p = NULL;
226	49.7k	EVP_PKEY *k = NULL;
227	49.7k	const EC_KEY *ec;
228	49.7k	const BIGNUM *d;
229	49.7k	int n;
230	49.7k	int ok = -1;
231
232	49.7k	if ((pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_EC, NULL)) == NULL \|\|
233	49.7k	EVP_PKEY_paramgen_init(pctx) <= 0 \|\|
234	49.7k	EVP_PKEY_CTX_set_ec_paramgen_curve_nid(pctx, es256_nid) <= 0 \|\|
235	49.7k	EVP_PKEY_paramgen(pctx, &p) <= 0) {
236	707	fido_log_debug("%s: EVP_PKEY_paramgen", __func__);
237	707	goto fail;
238	707	}
239
240	49.0k	if ((kctx = EVP_PKEY_CTX_new(p, NULL)) == NULL \|\|
241	49.0k	EVP_PKEY_keygen_init(kctx) <= 0 \|\| EVP_PKEY_keygen(kctx, &k) <= 0) {
242	897	fido_log_debug("%s: EVP_PKEY_keygen", __func__);
243	897	goto fail;
244	897	}
245
246	48.1k	if ((ec = EVP_PKEY_get0_EC_KEY(k)) == NULL \|\|
247	48.1k	(d = EC_KEY_get0_private_key(ec)) == NULL \|\|
248	48.1k	(n = BN_num_bytes(d)) < 0 \|\| (size_t)n > sizeof(key->d) \|\|
249	48.1k	(n = BN_bn2bin(d, key->d)) < 0 \|\| (size_t)n > sizeof(key->d)) {
250	1.19k	fido_log_debug("%s: EC_KEY_get0_private_key", __func__);
251	1.19k	goto fail;
252	1.19k	}
253
254	46.9k	ok = 0;
255	49.7k	fail:
256	49.7k	if (p != NULL)
257	49.0k	EVP_PKEY_free(p);
258	49.7k	if (k != NULL)
259	48.1k	EVP_PKEY_free(k);
260	49.7k	if (pctx != NULL)
261	49.6k	EVP_PKEY_CTX_free(pctx);
262	49.7k	if (kctx != NULL)
263	48.7k	EVP_PKEY_CTX_free(kctx);
264
265	49.7k	return (ok);
266	46.9k	}
267
268		EVP_PKEY *
269		es256_pk_to_EVP_PKEY(const es256_pk_t *k)
270	30.9k	{
271	30.9k	BN_CTX *bnctx = NULL;
272	30.9k	EC_KEY *ec = NULL;
273	30.9k	EC_POINT *q = NULL;
274	30.9k	EVP_PKEY *pkey = NULL;
275	30.9k	BIGNUM *x = NULL;
276	30.9k	BIGNUM *y = NULL;
277	30.9k	const EC_GROUP *g = NULL;
278	30.9k	int ok = -1;
279
280	30.9k	if ((bnctx = BN_CTX_new()) == NULL)
281	84	goto fail;
282
283	30.8k	BN_CTX_start(bnctx);
284
285	30.8k	if ((x = BN_CTX_get(bnctx)) == NULL \|\|
286	30.8k	(y = BN_CTX_get(bnctx)) == NULL)
287	340	goto fail;
288
289	30.4k	if (BN_bin2bn(k->x, sizeof(k->x), x) == NULL \|\|
290	30.4k	BN_bin2bn(k->y, sizeof(k->y), y) == NULL) {
291	576	fido_log_debug("%s: BN_bin2bn", __func__);
292	576	goto fail;
293	576	}
294
295	29.9k	if ((ec = EC_KEY_new_by_curve_name(es256_nid)) == NULL \|\|
296	29.9k	(g = EC_KEY_get0_group(ec)) == NULL) {
297	262	fido_log_debug("%s: EC_KEY init", __func__);
298	262	goto fail;
299	262	}
300
301	29.6k	if ((q = EC_POINT_new(g)) == NULL \|\|
302	29.6k	EC_POINT_set_affine_coordinates_GFp(g, q, x, y, bnctx) == 0 \|\|
303	29.6k	EC_KEY_set_public_key(ec, q) == 0) {
304	8.82k	fido_log_debug("%s: EC_KEY_set_public_key", __func__);
305	8.82k	goto fail;
306	8.82k	}
307
308	20.8k	if ((pkey = EVP_PKEY_new()) == NULL \|\|
309	20.8k	EVP_PKEY_assign_EC_KEY(pkey, ec) == 0) {
310	215	fido_log_debug("%s: EVP_PKEY_assign_EC_KEY", __func__);
311	215	goto fail;
312	215	}
313
314	20.6k	ec = NULL; /* at this point, ec belongs to evp */
315
316	20.6k	ok = 0;
317	30.9k	fail:
318	30.9k	if (bnctx != NULL) {
319	30.8k	BN_CTX_end(bnctx);
320	30.8k	BN_CTX_free(bnctx);
321	30.8k	}
322
323	30.9k	if (ec != NULL)
324	9.14k	EC_KEY_free(ec);
325	30.9k	if (q != NULL)
326	29.5k	EC_POINT_free(q);
327
328	30.9k	if (ok < 0 && pkey != NULL) {
329	138	EVP_PKEY_free(pkey);
330	138	pkey = NULL;
331	138	}
332
333	30.9k	return (pkey);
334	20.6k	}
335
336		int
337		es256_pk_from_EC_KEY(es256_pk_t pk, const EC_KEY ec)
338	46.0k	{
339	46.0k	BN_CTX *bnctx = NULL;
340	46.0k	BIGNUM *x = NULL;
341	46.0k	BIGNUM *y = NULL;
342	46.0k	const EC_POINT *q = NULL;
343	46.0k	EC_GROUP *g = NULL;
344	46.0k	size_t dx;
345	46.0k	size_t dy;
346	46.0k	int ok = FIDO_ERR_INTERNAL;
347	46.0k	int nx;
348	46.0k	int ny;
349
350	46.0k	if ((q = EC_KEY_get0_public_key(ec)) == NULL \|\|
351	46.0k	(g = EC_GROUP_new_by_curve_name(es256_nid)) == NULL \|\|
352	46.0k	(bnctx = BN_CTX_new()) == NULL)
353	328	goto fail;
354
355	45.7k	BN_CTX_start(bnctx);
356
357	45.7k	if ((x = BN_CTX_get(bnctx)) == NULL \|\|
358	45.7k	(y = BN_CTX_get(bnctx)) == NULL)
359	545	goto fail;
360
361	45.2k	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	45.2k	if (EC_POINT_get_affine_coordinates_GFp(g, q, x, y, bnctx) == 0 \|\|
368	45.2k	(nx = BN_num_bytes(x)) < 0 \|\| (size_t)nx > sizeof(pk->x) \|\|
369	45.2k	(ny = BN_num_bytes(y)) < 0 \|\| (size_t)ny > sizeof(pk->y)) {
370	242	fido_log_debug("%s: EC_POINT_get_affine_coordinates_GFp",
371	242	__func__);
372	242	goto fail;
373	242	}
374
375	44.9k	dx = sizeof(pk->x) - (size_t)nx;
376	44.9k	dy = sizeof(pk->y) - (size_t)ny;
377
378	44.9k	if ((nx = BN_bn2bin(x, pk->x + dx)) < 0 \|\| (size_t)nx > sizeof(pk->x) \|\|
379	44.9k	(ny = BN_bn2bin(y, pk->y + dy)) < 0 \|\| (size_t)ny > sizeof(pk->y)) {
380	596	fido_log_debug("%s: BN_bn2bin", __func__);
381	596	goto fail;
382	596	}
383
384	44.3k	ok = FIDO_OK;
385	46.0k	fail:
386	46.0k	EC_GROUP_free(g);
387
388	46.0k	if (bnctx != NULL) {
389	45.7k	BN_CTX_end(bnctx);
390	45.7k	BN_CTX_free(bnctx);
391	45.7k	}
392
393	46.0k	return (ok);
394	44.3k	}
395
396		int
397		es256_pk_from_EVP_PKEY(es256_pk_t pk, const EVP_PKEY pkey)
398	311	{
399	311	const EC_KEY *ec;
400
401	311	if (EVP_PKEY_base_id(pkey) != EVP_PKEY_EC \|\|
402	311	(ec = get0_EC_KEY(pkey)) == NULL)
403	11	return (FIDO_ERR_INVALID_ARGUMENT);
404
405	300	return (es256_pk_from_EC_KEY(pk, ec));
406	311	}
407
408		EVP_PKEY *
409		es256_sk_to_EVP_PKEY(const es256_sk_t *k)
410	19.7k	{
411	19.7k	BN_CTX *bnctx = NULL;
412	19.7k	EC_KEY *ec = NULL;
413	19.7k	EVP_PKEY *pkey = NULL;
414	19.7k	BIGNUM *d = NULL;
415	19.7k	int ok = -1;
416
417	19.7k	if ((bnctx = BN_CTX_new()) == NULL)
418	84	goto fail;
419
420	19.6k	BN_CTX_start(bnctx);
421
422	19.6k	if ((d = BN_CTX_get(bnctx)) == NULL \|\|
423	19.6k	BN_bin2bn(k->d, sizeof(k->d), d) == NULL) {
424	133	fido_log_debug("%s: BN_bin2bn", __func__);
425	133	goto fail;
426	133	}
427
428	19.5k	if ((ec = EC_KEY_new_by_curve_name(es256_nid)) == NULL \|\|
429	19.5k	EC_KEY_set_private_key(ec, d) == 0) {
430	69	fido_log_debug("%s: EC_KEY_set_private_key", __func__);
431	69	goto fail;
432	69	}
433
434	19.4k	if ((pkey = EVP_PKEY_new()) == NULL \|\|
435	19.4k	EVP_PKEY_assign_EC_KEY(pkey, ec) == 0) {
436	161	fido_log_debug("%s: EVP_PKEY_assign_EC_KEY", __func__);
437	161	goto fail;
438	161	}
439
440	19.2k	ec = NULL; /* at this point, ec belongs to evp */
441
442	19.2k	ok = 0;
443	19.7k	fail:
444	19.7k	if (bnctx != NULL) {
445	19.6k	BN_CTX_end(bnctx);
446	19.6k	BN_CTX_free(bnctx);
447	19.6k	}
448
449	19.7k	if (ec != NULL)
450	161	EC_KEY_free(ec);
451
452	19.7k	if (ok < 0 && pkey != NULL) {
453	87	EVP_PKEY_free(pkey);
454	87	pkey = NULL;
455	87	}
456
457	19.7k	return (pkey);
458	19.2k	}
459
460		int
461		es256_derive_pk(const es256_sk_t sk, es256_pk_t pk)
462	46.9k	{
463	46.9k	BIGNUM *d = NULL;
464	46.9k	EC_KEY *ec = NULL;
465	46.9k	EC_POINT *q = NULL;
466	46.9k	const EC_GROUP *g = NULL;
467	46.9k	int ok = -1;
468
469	46.9k	if ((d = BN_bin2bn(sk->d, (int)sizeof(sk->d), NULL)) == NULL \|\|
470	46.9k	(ec = EC_KEY_new_by_curve_name(es256_nid)) == NULL \|\|
471	46.9k	(g = EC_KEY_get0_group(ec)) == NULL \|\|
472	46.9k	(q = EC_POINT_new(g)) == NULL) {
473	1.20k	fido_log_debug("%s: get", __func__);
474	1.20k	goto fail;
475	1.20k	}
476
477	45.7k	if (EC_POINT_mul(g, q, d, NULL, NULL, NULL) == 0 \|\|
478	45.7k	EC_KEY_set_public_key(ec, q) == 0 \|\|
479	45.7k	es256_pk_from_EC_KEY(pk, ec) != FIDO_OK) {
480	1.59k	fido_log_debug("%s: set", __func__);
481	1.59k	goto fail;
482	1.59k	}
483
484	44.1k	ok = 0;
485	46.9k	fail:
486	46.9k	if (d != NULL)
487	46.7k	BN_clear_free(d);
488	46.9k	if (q != NULL)
489	45.7k	EC_POINT_free(q);
490	46.9k	if (ec != NULL)
491	46.4k	EC_KEY_free(ec);
492
493	46.9k	return (ok);
494	44.1k	}
495
496		int
497		es256_verify_sig(const fido_blob_t dgst, EVP_PKEY pkey,
498		const fido_blob_t *sig)
499	1.38k	{
500	1.38k	EVP_PKEY_CTX *pctx = NULL;
501	1.38k	int ok = -1;
502
503	1.38k	if (EVP_PKEY_base_id(pkey) != EVP_PKEY_EC) {
504	3	fido_log_debug("%s: EVP_PKEY_base_id", __func__);
505	3	goto fail;
506	3	}
507
508	1.38k	if ((pctx = EVP_PKEY_CTX_new(pkey, NULL)) == NULL \|\|
509	1.38k	EVP_PKEY_verify_init(pctx) != 1 \|\|
510	1.38k	EVP_PKEY_verify(pctx, sig->ptr, sig->len, dgst->ptr,
511	1.38k	dgst->len) != 1) {
512	1.38k	fido_log_debug("%s: EVP_PKEY_verify", __func__);
513	1.38k	goto fail;
514	1.38k	}
515
516	0	ok = 0;
517	1.38k	fail:
518	1.38k	EVP_PKEY_CTX_free(pctx);
519
520	1.38k	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	590	{
527	590	EVP_PKEY *pkey;
528	590	int ok = -1;
529
530	590	if ((pkey = es256_pk_to_EVP_PKEY(pk)) == NULL \|\|
531	590	es256_verify_sig(dgst, pkey, sig) < 0) {
532	590	fido_log_debug("%s: es256_verify_sig", __func__);
533	590	goto fail;
534	590	}
535
536	0	ok = 0;
537	590	fail:
538	590	EVP_PKEY_free(pkey);
539
540	590	return (ok);
541	0	}