/libfido2/src/rs256.c

Source (jump to first uncovered line)
/*
 * 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/rsa.h>
#include <openssl/obj_mac.h>

#include "fido.h"
#include "fido/rs256.h"

#if OPENSSL_VERSION_NUMBER >= 0x30000000
#define get0_RSA(x)     EVP_PKEY_get0_RSA((x))
#else
#define get0_RSA(x)     EVP_PKEY_get0((x))
#endif

#if defined(LIBRESSL_VERSION_NUMBER) && LIBRESSL_VERSION_NUMBER < 0x3050200fL
static EVP_MD *
rs256_get_EVP_MD(void)
{
        const EVP_MD *from;
        EVP_MD *to = NULL;

        if ((from = EVP_sha256()) != NULL && (to = malloc(sizeof(*to))) != NULL)
                memcpy(to, from, sizeof(*to));

        return (to);
}

static void
rs256_free_EVP_MD(EVP_MD *md)
{
        freezero(md, sizeof(*md));
}
#elif OPENSSL_VERSION_NUMBER >= 0x30000000
static EVP_MD *
rs256_get_EVP_MD(void)
{
        return (EVP_MD_fetch(NULL, "SHA2-256", NULL));
}

static void
rs256_free_EVP_MD(EVP_MD *md)
{
        EVP_MD_free(md);
}
#else
static EVP_MD *
rs256_get_EVP_MD(void)
{
        const EVP_MD *md;

        if ((md = EVP_sha256()) == NULL)
                return (NULL);

        return (EVP_MD_meth_dup(md));
}

static void
rs256_free_EVP_MD(EVP_MD *md)
{
        EVP_MD_meth_free(md);
}
#endif /* LIBRESSL_VERSION_NUMBER */

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

        memcpy(ptr, cbor_bytestring_handle(item), len);

        return (0);
}

static int
decode_rsa_pubkey(const cbor_item_t *key, const cbor_item_t *val, void *arg)
{
        rs256_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 0: /* modulus */
                return (decode_bignum(val, &k->n, sizeof(k->n)));
        case 1: /* public exponent */
                return (decode_bignum(val, &k->e, sizeof(k->e)));
        }

        return (0); /* ignore */
}

int
rs256_pk_decode(const cbor_item_t *item, rs256_pk_t *k)
{
        if (cbor_isa_map(item) == false ||
            cbor_map_is_definite(item) == false ||
            cbor_map_iter(item, k, decode_rsa_pubkey) < 0) {
                fido_log_debug("%s: cbor type", __func__);
                return (-1);
        }

        return (0);
}

rs256_pk_t *
rs256_pk_new(void)
{
        return (calloc(1, sizeof(rs256_pk_t)));
}

void
rs256_pk_free(rs256_pk_t **pkp)
{
        rs256_pk_t *pk;

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

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

int
rs256_pk_from_ptr(rs256_pk_t *pk, const void *ptr, size_t len)
{
        EVP_PKEY *pkey;

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

        memcpy(pk, ptr, sizeof(*pk));

        if ((pkey = rs256_pk_to_EVP_PKEY(pk)) == NULL) {
                fido_log_debug("%s: rs256_pk_to_EVP_PKEY", __func__);
                return (FIDO_ERR_INVALID_ARGUMENT);
        }

        EVP_PKEY_free(pkey);

        return (FIDO_OK);
}

EVP_PKEY *
rs256_pk_to_EVP_PKEY(const rs256_pk_t *k)
{
        RSA             *rsa = NULL;
        EVP_PKEY        *pkey = NULL;
        BIGNUM          *n = NULL;
        BIGNUM          *e = NULL;
        int              ok = -1;

        if ((n = BN_new()) == NULL || (e = BN_new()) == NULL)
                goto fail;

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

        if ((rsa = RSA_new()) == NULL || RSA_set0_key(rsa, n, e, NULL) == 0) {
                fido_log_debug("%s: RSA_set0_key", __func__);
                goto fail;
        }

        /* at this point, n and e belong to rsa */
        n = NULL;
        e = NULL;

        if (RSA_bits(rsa) != 2048) {
                fido_log_debug("%s: invalid key length", __func__);
                goto fail;
        }

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

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

        ok = 0;
fail:
        if (n != NULL)
                BN_free(n);
        if (e != NULL)
                BN_free(e);
        if (rsa != NULL)
                RSA_free(rsa);
        if (ok < 0 && pkey != NULL) {
                EVP_PKEY_free(pkey);
                pkey = NULL;
        }

        return (pkey);
}

int
rs256_pk_from_RSA(rs256_pk_t *pk, const RSA *rsa)
{
        const BIGNUM    *n = NULL;
        const BIGNUM    *e = NULL;
        const BIGNUM    *d = NULL;
        int              k;

        if (RSA_bits(rsa) != 2048) {
                fido_log_debug("%s: invalid key length", __func__);
                return (FIDO_ERR_INVALID_ARGUMENT);
        }

        RSA_get0_key(rsa, &n, &e, &d);

        if (n == NULL || e == NULL) {
                fido_log_debug("%s: RSA_get0_key", __func__);
                return (FIDO_ERR_INTERNAL);
        }

        if ((k = BN_num_bytes(n)) < 0 || (size_t)k > sizeof(pk->n) ||
            (k = BN_num_bytes(e)) < 0 || (size_t)k > sizeof(pk->e)) {
                fido_log_debug("%s: invalid key", __func__);
                return (FIDO_ERR_INTERNAL);
        }

        if ((k = BN_bn2bin(n, pk->n)) < 0 || (size_t)k > sizeof(pk->n) ||
            (k = BN_bn2bin(e, pk->e)) < 0 || (size_t)k > sizeof(pk->e)) {
                fido_log_debug("%s: BN_bn2bin", __func__);
                return (FIDO_ERR_INTERNAL);
        }

        return (FIDO_OK);
}

int
rs256_pk_from_EVP_PKEY(rs256_pk_t *pk, const EVP_PKEY *pkey)
{
        const RSA *rsa;

        if (EVP_PKEY_base_id(pkey) != EVP_PKEY_RSA ||
            (rsa = get0_RSA(pkey)) == NULL)
                return (FIDO_ERR_INVALID_ARGUMENT);

        return (rs256_pk_from_RSA(pk, rsa));
}

int
rs256_verify_sig(const fido_blob_t *dgst, EVP_PKEY *pkey,
    const fido_blob_t *sig)
{
        EVP_PKEY_CTX    *pctx = NULL;
        EVP_MD          *md = NULL;
        int              ok = -1;

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

        if ((md = rs256_get_EVP_MD()) == NULL) {
                fido_log_debug("%s: rs256_get_EVP_MD", __func__);
                goto fail;
        }

        if ((pctx = EVP_PKEY_CTX_new(pkey, NULL)) == NULL ||
            EVP_PKEY_verify_init(pctx) != 1 ||
            EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PADDING) != 1 ||
            EVP_PKEY_CTX_set_signature_md(pctx, md) != 1) {
                fido_log_debug("%s: EVP_PKEY_CTX", __func__);
                goto fail;
        }

        if (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);
        rs256_free_EVP_MD(md);

        return (ok);
}

int
rs256_pk_verify_sig(const fido_blob_t *dgst, const rs256_pk_t *pk,
    const fido_blob_t *sig)
{
        EVP_PKEY        *pkey;
        int              ok = -1;

        if ((pkey = rs256_pk_to_EVP_PKEY(pk)) == NULL ||
            rs256_verify_sig(dgst, pkey, sig) < 0) {
                fido_log_debug("%s: rs256_verify_sig", __func__);
                goto fail;
        }

        ok = 0;
fail:
        EVP_PKEY_free(pkey);

        return (ok);
}

Coverage Report

Created: 2024-02-05 19:20

Line	Count	Source (jump to first uncovered line)
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/rsa.h>
10		#include <openssl/obj_mac.h>
11
12		#include "fido.h"
13		#include "fido/rs256.h"
14
15		#if OPENSSL_VERSION_NUMBER >= 0x30000000
16	106	#define get0_RSA(x) EVP_PKEY_get0_RSA((x))
17		#else
18		#define get0_RSA(x) EVP_PKEY_get0((x))
19		#endif
20
21		#if defined(LIBRESSL_VERSION_NUMBER) && LIBRESSL_VERSION_NUMBER < 0x3050200fL
22		static EVP_MD *
23		rs256_get_EVP_MD(void)
24		{
25		const EVP_MD *from;
26		EVP_MD *to = NULL;
27
28		if ((from = EVP_sha256()) != NULL && (to = malloc(sizeof(*to))) != NULL)
29		memcpy(to, from, sizeof(*to));
30
31		return (to);
32		}
33
34		static void
35		rs256_free_EVP_MD(EVP_MD *md)
36		{
37		freezero(md, sizeof(*md));
38		}
39		#elif OPENSSL_VERSION_NUMBER >= 0x30000000
40		static EVP_MD *
41		rs256_get_EVP_MD(void)
42	67	{
43	67	return (EVP_MD_fetch(NULL, "SHA2-256", NULL));
44	67	}
45
46		static void
47		rs256_free_EVP_MD(EVP_MD *md)
48	69	{
49	69	EVP_MD_free(md);
50	69	}
51		#else
52		static EVP_MD *
53		rs256_get_EVP_MD(void)
54		{
55		const EVP_MD *md;
56
57		if ((md = EVP_sha256()) == NULL)
58		return (NULL);
59
60		return (EVP_MD_meth_dup(md));
61		}
62
63		static void
64		rs256_free_EVP_MD(EVP_MD *md)
65		{
66		EVP_MD_meth_free(md);
67		}
68		#endif /* LIBRESSL_VERSION_NUMBER */
69
70		static int
71		decode_bignum(const cbor_item_t item, void ptr, size_t len)
72	284	{
73	284	if (cbor_isa_bytestring(item) == false \|\|
74	284	cbor_bytestring_is_definite(item) == false \|\|
75	284	cbor_bytestring_length(item) != len) {
76	31	fido_log_debug("%s: cbor type", __func__);
77	31	return (-1);
78	31	}
79
80	253	memcpy(ptr, cbor_bytestring_handle(item), len);
81
82	253	return (0);
83	284	}
84
85		static int
86		decode_rsa_pubkey(const cbor_item_t key, const cbor_item_t val, void *arg)
87	2.04k	{
88	2.04k	rs256_pk_t *k = arg;
89
90	2.04k	if (cbor_isa_negint(key) == false \|\|
91	2.04k	cbor_int_get_width(key) != CBOR_INT_8)
92	1.46k	return (0); /* ignore */
93
94	571	switch (cbor_get_uint8(key)) {
95	139	case 0: /* modulus */
96	139	return (decode_bignum(val, &k->n, sizeof(k->n)));
97	145	case 1: /* public exponent */
98	145	return (decode_bignum(val, &k->e, sizeof(k->e)));
99	571	}
100
101	287	return (0); /* ignore */
102	571	}
103
104		int
105		rs256_pk_decode(const cbor_item_t item, rs256_pk_t k)
106	536	{
107	536	if (cbor_isa_map(item) == false \|\|
108	536	cbor_map_is_definite(item) == false \|\|
109	536	cbor_map_iter(item, k, decode_rsa_pubkey) < 0) {
110	40	fido_log_debug("%s: cbor type", __func__);
111	40	return (-1);
112	40	}
113
114	496	return (0);
115	536	}
116
117		rs256_pk_t *
118		rs256_pk_new(void)
119	1.04k	{
120	1.04k	return (calloc(1, sizeof(rs256_pk_t)));
121	1.04k	}
122
123		void
124		rs256_pk_free(rs256_pk_t **pkp)
125	4.69k	{
126	4.69k	rs256_pk_t *pk;
127
128	4.69k	if (pkp == NULL \|\| (pk = *pkp) == NULL)
129	3.64k	return;
130
131	1.04k	freezero(pk, sizeof(*pk));
132	1.04k	*pkp = NULL;
133	1.04k	}
134
135		int
136		rs256_pk_from_ptr(rs256_pk_t pk, const void ptr, size_t len)
137	941	{
138	941	EVP_PKEY *pkey;
139
140	941	if (len < sizeof(*pk))
141	728	return (FIDO_ERR_INVALID_ARGUMENT);
142
143	213	memcpy(pk, ptr, sizeof(*pk));
144
145	213	if ((pkey = rs256_pk_to_EVP_PKEY(pk)) == NULL) {
146	96	fido_log_debug("%s: rs256_pk_to_EVP_PKEY", __func__);
147	96	return (FIDO_ERR_INVALID_ARGUMENT);
148	96	}
149
150	117	EVP_PKEY_free(pkey);
151
152	117	return (FIDO_OK);
153	213	}
154
155		EVP_PKEY *
156		rs256_pk_to_EVP_PKEY(const rs256_pk_t *k)
157	1.28k	{
158	1.28k	RSA *rsa = NULL;
159	1.28k	EVP_PKEY *pkey = NULL;
160	1.28k	BIGNUM *n = NULL;
161	1.28k	BIGNUM *e = NULL;
162	1.28k	int ok = -1;
163
164	1.28k	if ((n = BN_new()) == NULL \|\| (e = BN_new()) == NULL)
165	19	goto fail;
166
167	1.26k	if (BN_bin2bn(k->n, sizeof(k->n), n) == NULL \|\|
168	1.26k	BN_bin2bn(k->e, sizeof(k->e), e) == NULL) {
169	49	fido_log_debug("%s: BN_bin2bn", __func__);
170	49	goto fail;
171	49	}
172
173	1.21k	if ((rsa = RSA_new()) == NULL \|\| RSA_set0_key(rsa, n, e, NULL) == 0) {
174	22	fido_log_debug("%s: RSA_set0_key", __func__);
175	22	goto fail;
176	22	}
177
178		/* at this point, n and e belong to rsa */
179	1.19k	n = NULL;
180	1.19k	e = NULL;
181
182	1.19k	if (RSA_bits(rsa) != 2048) {
183	889	fido_log_debug("%s: invalid key length", __func__);
184	889	goto fail;
185	889	}
186
187	301	if ((pkey = EVP_PKEY_new()) == NULL \|\|
188	301	EVP_PKEY_assign_RSA(pkey, rsa) == 0) {
189	10	fido_log_debug("%s: EVP_PKEY_assign_RSA", __func__);
190	10	goto fail;
191	10	}
192
193	291	rsa = NULL; /* at this point, rsa belongs to evp */
194
195	291	ok = 0;
196	1.28k	fail:
197	1.28k	if (n != NULL)
198	80	BN_free(n);
199	1.28k	if (e != NULL)
200	71	BN_free(e);
201	1.28k	if (rsa != NULL)
202	914	RSA_free(rsa);
203	1.28k	if (ok < 0 && pkey != NULL) {
204	6	EVP_PKEY_free(pkey);
205	6	pkey = NULL;
206	6	}
207
208	1.28k	return (pkey);
209	291	}
210
211		int
212		rs256_pk_from_RSA(rs256_pk_t pk, const RSA rsa)
213	104	{
214	104	const BIGNUM *n = NULL;
215	104	const BIGNUM *e = NULL;
216	104	const BIGNUM *d = NULL;
217	104	int k;
218
219	104	if (RSA_bits(rsa) != 2048) {
220	0	fido_log_debug("%s: invalid key length", __func__);
221	0	return (FIDO_ERR_INVALID_ARGUMENT);
222	0	}
223
224	104	RSA_get0_key(rsa, &n, &e, &d);
225
226	104	if (n == NULL \|\| e == NULL) {
227	0	fido_log_debug("%s: RSA_get0_key", __func__);
228	0	return (FIDO_ERR_INTERNAL);
229	0	}
230
231	104	if ((k = BN_num_bytes(n)) < 0 \|\| (size_t)k > sizeof(pk->n) \|\|
232	104	(k = BN_num_bytes(e)) < 0 \|\| (size_t)k > sizeof(pk->e)) {
233	0	fido_log_debug("%s: invalid key", __func__);
234	0	return (FIDO_ERR_INTERNAL);
235	0	}
236
237	104	if ((k = BN_bn2bin(n, pk->n)) < 0 \|\| (size_t)k > sizeof(pk->n) \|\|
238	104	(k = BN_bn2bin(e, pk->e)) < 0 \|\| (size_t)k > sizeof(pk->e)) {
239	4	fido_log_debug("%s: BN_bn2bin", __func__);
240	4	return (FIDO_ERR_INTERNAL);
241	4	}
242
243	100	return (FIDO_OK);
244	104	}
245
246		int
247		rs256_pk_from_EVP_PKEY(rs256_pk_t pk, const EVP_PKEY pkey)
248	106	{
249	106	const RSA *rsa;
250
251	106	if (EVP_PKEY_base_id(pkey) != EVP_PKEY_RSA \|\|
252	106	(rsa = get0_RSA(pkey)) == NULL)
253	2	return (FIDO_ERR_INVALID_ARGUMENT);
254
255	104	return (rs256_pk_from_RSA(pk, rsa));
256	106	}
257
258		int
259		rs256_verify_sig(const fido_blob_t dgst, EVP_PKEY pkey,
260		const fido_blob_t *sig)
261	69	{
262	69	EVP_PKEY_CTX *pctx = NULL;
263	69	EVP_MD *md = NULL;
264	69	int ok = -1;
265
266	69	if (EVP_PKEY_base_id(pkey) != EVP_PKEY_RSA) {
267	2	fido_log_debug("%s: EVP_PKEY_base_id", __func__);
268	2	goto fail;
269	2	}
270
271	67	if ((md = rs256_get_EVP_MD()) == NULL) {
272	0	fido_log_debug("%s: rs256_get_EVP_MD", __func__);
273	0	goto fail;
274	0	}
275
276	67	if ((pctx = EVP_PKEY_CTX_new(pkey, NULL)) == NULL \|\|
277	67	EVP_PKEY_verify_init(pctx) != 1 \|\|
278	67	EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PADDING) != 1 \|\|
279	67	EVP_PKEY_CTX_set_signature_md(pctx, md) != 1) {
280	4	fido_log_debug("%s: EVP_PKEY_CTX", __func__);
281	4	goto fail;
282	4	}
283
284	63	if (EVP_PKEY_verify(pctx, sig->ptr, sig->len, dgst->ptr,
285	63	dgst->len) != 1) {
286	63	fido_log_debug("%s: EVP_PKEY_verify", __func__);
287	63	goto fail;
288	63	}
289
290	0	ok = 0;
291	69	fail:
292	69	EVP_PKEY_CTX_free(pctx);
293	69	rs256_free_EVP_MD(md);
294
295	69	return (ok);
296	0	}
297
298		int
299		rs256_pk_verify_sig(const fido_blob_t dgst, const rs256_pk_t pk,
300		const fido_blob_t *sig)
301	126	{
302	126	EVP_PKEY *pkey;
303	126	int ok = -1;
304
305	126	if ((pkey = rs256_pk_to_EVP_PKEY(pk)) == NULL \|\|
306	126	rs256_verify_sig(dgst, pkey, sig) < 0) {
307	126	fido_log_debug("%s: rs256_verify_sig", __func__);
308	126	goto fail;
309	126	}
310
311	0	ok = 0;
312	126	fail:
313	126	EVP_PKEY_free(pkey);
314
315	126	return (ok);
316	0	}