1 /* $OpenBSD: ssh-ed25519-sk.c,v 1.15 2022/10/28 00:44:44 djm Exp $ */
3 * Copyright (c) 2019 Markus Friedl. All rights reserved.
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 /* #define DEBUG_SK 1 */
22 #define SSHKEY_INTERNAL
23 #include <sys/types.h>
26 #include "crypto_api.h"
38 /* Reuse some ED25519 internals */
39 extern struct sshkey_impl_funcs sshkey_ed25519_funcs;
42 ssh_ed25519_sk_cleanup(struct sshkey *k)
45 sshkey_ed25519_funcs.cleanup(k);
49 ssh_ed25519_sk_equal(const struct sshkey *a, const struct sshkey *b)
51 if (!sshkey_sk_fields_equal(a, b))
53 if (!sshkey_ed25519_funcs.equal(a, b))
59 ssh_ed25519_sk_serialize_public(const struct sshkey *key, struct sshbuf *b,
60 enum sshkey_serialize_rep opts)
64 if ((r = sshkey_ed25519_funcs.serialize_public(key, b, opts)) != 0)
66 if ((r = sshkey_serialize_sk(key, b)) != 0)
73 ssh_ed25519_sk_serialize_private(const struct sshkey *key, struct sshbuf *b,
74 enum sshkey_serialize_rep opts)
78 if ((r = sshkey_ed25519_funcs.serialize_public(key, b, opts)) != 0)
80 if ((r = sshkey_serialize_private_sk(key, b)) != 0)
87 ssh_ed25519_sk_copy_public(const struct sshkey *from, struct sshkey *to)
91 if ((r = sshkey_ed25519_funcs.copy_public(from, to)) != 0)
93 if ((r = sshkey_copy_public_sk(from, to)) != 0)
99 ssh_ed25519_sk_deserialize_public(const char *ktype, struct sshbuf *b,
104 if ((r = sshkey_ed25519_funcs.deserialize_public(ktype, b, key)) != 0)
106 if ((r = sshkey_deserialize_sk(b, key)) != 0)
112 ssh_ed25519_sk_deserialize_private(const char *ktype, struct sshbuf *b,
117 if ((r = sshkey_ed25519_funcs.deserialize_public(ktype, b, key)) != 0)
119 if ((r = sshkey_private_deserialize_sk(b, key)) != 0)
125 ssh_ed25519_sk_verify(const struct sshkey *key,
126 const u_char *sig, size_t siglen,
127 const u_char *data, size_t dlen, const char *alg, u_int compat,
128 struct sshkey_sig_details **detailsp)
130 struct sshbuf *b = NULL;
131 struct sshbuf *encoded = NULL;
133 const u_char *sigblob;
141 unsigned long long smlen = 0, mlen = 0;
142 int r = SSH_ERR_INTERNAL_ERROR;
144 struct sshkey_sig_details *details = NULL;
146 if (detailsp != NULL)
150 sshkey_type_plain(key->type) != KEY_ED25519_SK ||
151 key->ed25519_pk == NULL ||
152 sig == NULL || siglen == 0)
153 return SSH_ERR_INVALID_ARGUMENT;
155 if ((b = sshbuf_from(sig, siglen)) == NULL)
156 return SSH_ERR_ALLOC_FAIL;
157 if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
158 sshbuf_get_string_direct(b, &sigblob, &len) != 0 ||
159 sshbuf_get_u8(b, &sig_flags) != 0 ||
160 sshbuf_get_u32(b, &sig_counter) != 0) {
161 r = SSH_ERR_INVALID_FORMAT;
165 fprintf(stderr, "%s: data:\n", __func__);
166 /* sshbuf_dump_data(data, datalen, stderr); */
167 fprintf(stderr, "%s: sigblob:\n", __func__);
168 sshbuf_dump_data(sigblob, len, stderr);
169 fprintf(stderr, "%s: sig_flags = 0x%02x, sig_counter = %u\n",
170 __func__, sig_flags, sig_counter);
172 if (strcmp(sshkey_ssh_name_plain(key), ktype) != 0) {
173 r = SSH_ERR_KEY_TYPE_MISMATCH;
176 if (sshbuf_len(b) != 0) {
177 r = SSH_ERR_UNEXPECTED_TRAILING_DATA;
180 if (len > crypto_sign_ed25519_BYTES) {
181 r = SSH_ERR_INVALID_FORMAT;
184 if (ssh_digest_memory(SSH_DIGEST_SHA256, key->sk_application,
185 strlen(key->sk_application), apphash, sizeof(apphash)) != 0 ||
186 ssh_digest_memory(SSH_DIGEST_SHA256, data, dlen,
187 msghash, sizeof(msghash)) != 0) {
188 r = SSH_ERR_INVALID_ARGUMENT;
192 fprintf(stderr, "%s: hashed application:\n", __func__);
193 sshbuf_dump_data(apphash, sizeof(apphash), stderr);
194 fprintf(stderr, "%s: hashed message:\n", __func__);
195 sshbuf_dump_data(msghash, sizeof(msghash), stderr);
197 if ((details = calloc(1, sizeof(*details))) == NULL) {
198 r = SSH_ERR_ALLOC_FAIL;
201 details->sk_counter = sig_counter;
202 details->sk_flags = sig_flags;
203 if ((encoded = sshbuf_new()) == NULL) {
204 r = SSH_ERR_ALLOC_FAIL;
207 if (sshbuf_put(encoded, sigblob, len) != 0 ||
208 sshbuf_put(encoded, apphash, sizeof(apphash)) != 0 ||
209 sshbuf_put_u8(encoded, sig_flags) != 0 ||
210 sshbuf_put_u32(encoded, sig_counter) != 0 ||
211 sshbuf_put(encoded, msghash, sizeof(msghash)) != 0) {
212 r = SSH_ERR_ALLOC_FAIL;
216 fprintf(stderr, "%s: signed buf:\n", __func__);
217 sshbuf_dump(encoded, stderr);
219 sm = sshbuf_ptr(encoded);
220 smlen = sshbuf_len(encoded);
222 if ((m = malloc(smlen)) == NULL) {
223 r = SSH_ERR_ALLOC_FAIL;
226 if ((ret = crypto_sign_ed25519_open(m, &mlen, sm, smlen,
227 key->ed25519_pk)) != 0) {
228 debug2_f("crypto_sign_ed25519_open failed: %d", ret);
230 if (ret != 0 || mlen != smlen - len) {
231 r = SSH_ERR_SIGNATURE_INVALID;
234 /* XXX compare 'm' and 'sm + len' ? */
237 if (detailsp != NULL) {
243 freezero(m, smlen); /* NB mlen may be invalid if r != 0 */
244 sshkey_sig_details_free(details);
246 sshbuf_free(encoded);
251 static const struct sshkey_impl_funcs sshkey_ed25519_sk_funcs = {
254 /* .cleanup = */ ssh_ed25519_sk_cleanup,
255 /* .equal = */ ssh_ed25519_sk_equal,
256 /* .ssh_serialize_public = */ ssh_ed25519_sk_serialize_public,
257 /* .ssh_deserialize_public = */ ssh_ed25519_sk_deserialize_public,
258 /* .ssh_serialize_private = */ ssh_ed25519_sk_serialize_private,
259 /* .ssh_deserialize_private = */ ssh_ed25519_sk_deserialize_private,
260 /* .generate = */ NULL,
261 /* .copy_public = */ ssh_ed25519_sk_copy_public,
263 /* .verify = */ ssh_ed25519_sk_verify,
266 const struct sshkey_impl sshkey_ed25519_sk_impl = {
267 /* .name = */ "sk-ssh-ed25519@openssh.com",
268 /* .shortname = */ "ED25519-SK",
269 /* .sigalg = */ NULL,
270 /* .type = */ KEY_ED25519_SK,
274 /* .keybits = */ 256,
275 /* .funcs = */ &sshkey_ed25519_sk_funcs,
278 const struct sshkey_impl sshkey_ed25519_sk_cert_impl = {
279 /* .name = */ "sk-ssh-ed25519-cert-v01@openssh.com",
280 /* .shortname = */ "ED25519-SK-CERT",
281 /* .sigalg = */ NULL,
282 /* .type = */ KEY_ED25519_SK_CERT,
286 /* .keybits = */ 256,
287 /* .funcs = */ &sshkey_ed25519_sk_funcs,