1 /* $OpenBSD: ssh-ecdsa.c,v 1.26 2023/03/08 04:43:12 guenther Exp $ */
3 * Copyright (c) 2000 Markus Friedl. All rights reserved.
4 * Copyright (c) 2010 Damien Miller. All rights reserved.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 #if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC)
31 #include <sys/types.h>
33 #include <openssl/bn.h>
34 #include <openssl/ec.h>
35 #include <openssl/ecdsa.h>
36 #include <openssl/evp.h>
43 #define SSHKEY_INTERNAL
46 #include "openbsd-compat/openssl-compat.h"
49 ssh_ecdsa_size(const struct sshkey *key)
51 switch (key->ecdsa_nid) {
52 case NID_X9_62_prime256v1:
56 #ifdef OPENSSL_HAS_NISTP521
66 ssh_ecdsa_cleanup(struct sshkey *k)
68 EC_KEY_free(k->ecdsa);
73 ssh_ecdsa_equal(const struct sshkey *a, const struct sshkey *b)
75 const EC_GROUP *grp_a, *grp_b;
76 const EC_POINT *pub_a, *pub_b;
78 if (a->ecdsa == NULL || b->ecdsa == NULL)
80 if ((grp_a = EC_KEY_get0_group(a->ecdsa)) == NULL ||
81 (grp_b = EC_KEY_get0_group(b->ecdsa)) == NULL)
83 if ((pub_a = EC_KEY_get0_public_key(a->ecdsa)) == NULL ||
84 (pub_b = EC_KEY_get0_public_key(b->ecdsa)) == NULL)
86 if (EC_GROUP_cmp(grp_a, grp_b, NULL) != 0)
88 if (EC_POINT_cmp(grp_a, pub_a, pub_b, NULL) != 0)
95 ssh_ecdsa_serialize_public(const struct sshkey *key, struct sshbuf *b,
96 enum sshkey_serialize_rep opts)
100 if (key->ecdsa == NULL)
101 return SSH_ERR_INVALID_ARGUMENT;
102 if ((r = sshbuf_put_cstring(b,
103 sshkey_curve_nid_to_name(key->ecdsa_nid))) != 0 ||
104 (r = sshbuf_put_eckey(b, key->ecdsa)) != 0)
111 ssh_ecdsa_serialize_private(const struct sshkey *key, struct sshbuf *b,
112 enum sshkey_serialize_rep opts)
116 if (!sshkey_is_cert(key)) {
117 if ((r = ssh_ecdsa_serialize_public(key, b, opts)) != 0)
120 if ((r = sshbuf_put_bignum2(b,
121 EC_KEY_get0_private_key(key->ecdsa))) != 0)
127 ssh_ecdsa_generate(struct sshkey *k, int bits)
131 if ((k->ecdsa_nid = sshkey_ecdsa_bits_to_nid(bits)) == -1)
132 return SSH_ERR_KEY_LENGTH;
133 if ((private = EC_KEY_new_by_curve_name(k->ecdsa_nid)) == NULL)
134 return SSH_ERR_ALLOC_FAIL;
135 if (EC_KEY_generate_key(private) != 1) {
136 EC_KEY_free(private);
137 return SSH_ERR_LIBCRYPTO_ERROR;
139 EC_KEY_set_asn1_flag(private, OPENSSL_EC_NAMED_CURVE);
145 ssh_ecdsa_copy_public(const struct sshkey *from, struct sshkey *to)
147 to->ecdsa_nid = from->ecdsa_nid;
148 if ((to->ecdsa = EC_KEY_new_by_curve_name(from->ecdsa_nid)) == NULL)
149 return SSH_ERR_ALLOC_FAIL;
150 if (EC_KEY_set_public_key(to->ecdsa,
151 EC_KEY_get0_public_key(from->ecdsa)) != 1)
152 return SSH_ERR_LIBCRYPTO_ERROR; /* caller will free k->ecdsa */
157 ssh_ecdsa_deserialize_public(const char *ktype, struct sshbuf *b,
163 if ((key->ecdsa_nid = sshkey_ecdsa_nid_from_name(ktype)) == -1)
164 return SSH_ERR_INVALID_ARGUMENT;
165 if ((r = sshbuf_get_cstring(b, &curve, NULL)) != 0)
167 if (key->ecdsa_nid != sshkey_curve_name_to_nid(curve)) {
168 r = SSH_ERR_EC_CURVE_MISMATCH;
171 EC_KEY_free(key->ecdsa);
173 if ((key->ecdsa = EC_KEY_new_by_curve_name(key->ecdsa_nid)) == NULL) {
174 r = SSH_ERR_LIBCRYPTO_ERROR;
177 if ((r = sshbuf_get_eckey(b, key->ecdsa)) != 0)
179 if (sshkey_ec_validate_public(EC_KEY_get0_group(key->ecdsa),
180 EC_KEY_get0_public_key(key->ecdsa)) != 0) {
181 r = SSH_ERR_KEY_INVALID_EC_VALUE;
187 sshkey_dump_ec_point(EC_KEY_get0_group(key->ecdsa),
188 EC_KEY_get0_public_key(key->ecdsa));
193 EC_KEY_free(key->ecdsa);
200 ssh_ecdsa_deserialize_private(const char *ktype, struct sshbuf *b,
204 BIGNUM *exponent = NULL;
206 if (!sshkey_is_cert(key)) {
207 if ((r = ssh_ecdsa_deserialize_public(ktype, b, key)) != 0)
210 if ((r = sshbuf_get_bignum2(b, &exponent)) != 0)
212 if (EC_KEY_set_private_key(key->ecdsa, exponent) != 1) {
213 r = SSH_ERR_LIBCRYPTO_ERROR;
216 if ((r = sshkey_ec_validate_private(key->ecdsa)) != 0)
221 BN_clear_free(exponent);
226 ssh_ecdsa_sign(struct sshkey *key,
227 u_char **sigp, size_t *lenp,
228 const u_char *data, size_t dlen,
229 const char *alg, const char *sk_provider, const char *sk_pin, u_int compat)
231 ECDSA_SIG *esig = NULL;
232 const BIGNUM *sig_r, *sig_s;
234 u_char digest[SSH_DIGEST_MAX_LENGTH];
236 struct sshbuf *b = NULL, *bb = NULL;
237 int ret = SSH_ERR_INTERNAL_ERROR;
244 if (key == NULL || key->ecdsa == NULL ||
245 sshkey_type_plain(key->type) != KEY_ECDSA)
246 return SSH_ERR_INVALID_ARGUMENT;
248 if ((hash_alg = sshkey_ec_nid_to_hash_alg(key->ecdsa_nid)) == -1 ||
249 (hlen = ssh_digest_bytes(hash_alg)) == 0)
250 return SSH_ERR_INTERNAL_ERROR;
251 if ((ret = ssh_digest_memory(hash_alg, data, dlen,
252 digest, sizeof(digest))) != 0)
255 if ((esig = ECDSA_do_sign(digest, hlen, key->ecdsa)) == NULL) {
256 ret = SSH_ERR_LIBCRYPTO_ERROR;
260 if ((bb = sshbuf_new()) == NULL || (b = sshbuf_new()) == NULL) {
261 ret = SSH_ERR_ALLOC_FAIL;
264 ECDSA_SIG_get0(esig, &sig_r, &sig_s);
265 if ((ret = sshbuf_put_bignum2(bb, sig_r)) != 0 ||
266 (ret = sshbuf_put_bignum2(bb, sig_s)) != 0)
268 if ((ret = sshbuf_put_cstring(b, sshkey_ssh_name_plain(key))) != 0 ||
269 (ret = sshbuf_put_stringb(b, bb)) != 0)
273 if ((*sigp = malloc(len)) == NULL) {
274 ret = SSH_ERR_ALLOC_FAIL;
277 memcpy(*sigp, sshbuf_ptr(b), len);
283 explicit_bzero(digest, sizeof(digest));
286 ECDSA_SIG_free(esig);
291 ssh_ecdsa_verify(const struct sshkey *key,
292 const u_char *sig, size_t siglen,
293 const u_char *data, size_t dlen, const char *alg, u_int compat,
294 struct sshkey_sig_details **detailsp)
296 ECDSA_SIG *esig = NULL;
297 BIGNUM *sig_r = NULL, *sig_s = NULL;
299 u_char digest[SSH_DIGEST_MAX_LENGTH];
301 int ret = SSH_ERR_INTERNAL_ERROR;
302 struct sshbuf *b = NULL, *sigbuf = NULL;
305 if (key == NULL || key->ecdsa == NULL ||
306 sshkey_type_plain(key->type) != KEY_ECDSA ||
307 sig == NULL || siglen == 0)
308 return SSH_ERR_INVALID_ARGUMENT;
310 if ((hash_alg = sshkey_ec_nid_to_hash_alg(key->ecdsa_nid)) == -1 ||
311 (hlen = ssh_digest_bytes(hash_alg)) == 0)
312 return SSH_ERR_INTERNAL_ERROR;
314 /* fetch signature */
315 if ((b = sshbuf_from(sig, siglen)) == NULL)
316 return SSH_ERR_ALLOC_FAIL;
317 if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
318 sshbuf_froms(b, &sigbuf) != 0) {
319 ret = SSH_ERR_INVALID_FORMAT;
322 if (strcmp(sshkey_ssh_name_plain(key), ktype) != 0) {
323 ret = SSH_ERR_KEY_TYPE_MISMATCH;
326 if (sshbuf_len(b) != 0) {
327 ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
331 /* parse signature */
332 if (sshbuf_get_bignum2(sigbuf, &sig_r) != 0 ||
333 sshbuf_get_bignum2(sigbuf, &sig_s) != 0) {
334 ret = SSH_ERR_INVALID_FORMAT;
337 if ((esig = ECDSA_SIG_new()) == NULL) {
338 ret = SSH_ERR_ALLOC_FAIL;
341 if (!ECDSA_SIG_set0(esig, sig_r, sig_s)) {
342 ret = SSH_ERR_LIBCRYPTO_ERROR;
345 sig_r = sig_s = NULL; /* transferred */
347 if (sshbuf_len(sigbuf) != 0) {
348 ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
351 if ((ret = ssh_digest_memory(hash_alg, data, dlen,
352 digest, sizeof(digest))) != 0)
355 switch (ECDSA_do_verify(digest, hlen, esig, key->ecdsa)) {
360 ret = SSH_ERR_SIGNATURE_INVALID;
363 ret = SSH_ERR_LIBCRYPTO_ERROR;
368 explicit_bzero(digest, sizeof(digest));
371 ECDSA_SIG_free(esig);
372 BN_clear_free(sig_r);
373 BN_clear_free(sig_s);
378 /* NB. not static; used by ECDSA-SK */
379 const struct sshkey_impl_funcs sshkey_ecdsa_funcs = {
380 /* .size = */ ssh_ecdsa_size,
382 /* .cleanup = */ ssh_ecdsa_cleanup,
383 /* .equal = */ ssh_ecdsa_equal,
384 /* .ssh_serialize_public = */ ssh_ecdsa_serialize_public,
385 /* .ssh_deserialize_public = */ ssh_ecdsa_deserialize_public,
386 /* .ssh_serialize_private = */ ssh_ecdsa_serialize_private,
387 /* .ssh_deserialize_private = */ ssh_ecdsa_deserialize_private,
388 /* .generate = */ ssh_ecdsa_generate,
389 /* .copy_public = */ ssh_ecdsa_copy_public,
390 /* .sign = */ ssh_ecdsa_sign,
391 /* .verify = */ ssh_ecdsa_verify,
394 const struct sshkey_impl sshkey_ecdsa_nistp256_impl = {
395 /* .name = */ "ecdsa-sha2-nistp256",
396 /* .shortname = */ "ECDSA",
397 /* .sigalg = */ NULL,
398 /* .type = */ KEY_ECDSA,
399 /* .nid = */ NID_X9_62_prime256v1,
403 /* .funcs = */ &sshkey_ecdsa_funcs,
406 const struct sshkey_impl sshkey_ecdsa_nistp256_cert_impl = {
407 /* .name = */ "ecdsa-sha2-nistp256-cert-v01@openssh.com",
408 /* .shortname = */ "ECDSA-CERT",
409 /* .sigalg = */ NULL,
410 /* .type = */ KEY_ECDSA_CERT,
411 /* .nid = */ NID_X9_62_prime256v1,
415 /* .funcs = */ &sshkey_ecdsa_funcs,
418 const struct sshkey_impl sshkey_ecdsa_nistp384_impl = {
419 /* .name = */ "ecdsa-sha2-nistp384",
420 /* .shortname = */ "ECDSA",
421 /* .sigalg = */ NULL,
422 /* .type = */ KEY_ECDSA,
423 /* .nid = */ NID_secp384r1,
427 /* .funcs = */ &sshkey_ecdsa_funcs,
430 const struct sshkey_impl sshkey_ecdsa_nistp384_cert_impl = {
431 /* .name = */ "ecdsa-sha2-nistp384-cert-v01@openssh.com",
432 /* .shortname = */ "ECDSA-CERT",
433 /* .sigalg = */ NULL,
434 /* .type = */ KEY_ECDSA_CERT,
435 /* .nid = */ NID_secp384r1,
439 /* .funcs = */ &sshkey_ecdsa_funcs,
442 #ifdef OPENSSL_HAS_NISTP521
443 const struct sshkey_impl sshkey_ecdsa_nistp521_impl = {
444 /* .name = */ "ecdsa-sha2-nistp521",
445 /* .shortname = */ "ECDSA",
446 /* .sigalg = */ NULL,
447 /* .type = */ KEY_ECDSA,
448 /* .nid = */ NID_secp521r1,
452 /* .funcs = */ &sshkey_ecdsa_funcs,
455 const struct sshkey_impl sshkey_ecdsa_nistp521_cert_impl = {
456 /* .name = */ "ecdsa-sha2-nistp521-cert-v01@openssh.com",
457 /* .shortname = */ "ECDSA-CERT",
458 /* .sigalg = */ NULL,
459 /* .type = */ KEY_ECDSA_CERT,
460 /* .nid = */ NID_secp521r1,
464 /* .funcs = */ &sshkey_ecdsa_funcs,
468 #endif /* WITH_OPENSSL && OPENSSL_HAS_ECC */