/src/openssh/ssh-ed25519.c
Line | Count | Source |
1 | | /* $OpenBSD: ssh-ed25519.c,v 1.20 2025/07/24 06:12:08 djm Exp $ */ |
2 | | /* |
3 | | * Copyright (c) 2013 Markus Friedl <markus@openbsd.org> |
4 | | * |
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. |
8 | | * |
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. |
16 | | */ |
17 | | |
18 | | #include "includes.h" |
19 | | |
20 | | #include <sys/types.h> |
21 | | #include <limits.h> |
22 | | |
23 | | #include "crypto_api.h" |
24 | | |
25 | | #include <string.h> |
26 | | #include <stdarg.h> |
27 | | |
28 | | #include "log.h" |
29 | | #include "sshbuf.h" |
30 | | #define SSHKEY_INTERNAL |
31 | | #include "sshkey.h" |
32 | | #include "ssherr.h" |
33 | | #include "ssh.h" |
34 | | |
35 | | static void |
36 | | ssh_ed25519_cleanup(struct sshkey *k) |
37 | 2.26k | { |
38 | 2.26k | freezero(k->ed25519_pk, ED25519_PK_SZ); |
39 | 2.26k | freezero(k->ed25519_sk, ED25519_SK_SZ); |
40 | 2.26k | k->ed25519_pk = NULL; |
41 | 2.26k | k->ed25519_sk = NULL; |
42 | 2.26k | } |
43 | | |
44 | | static int |
45 | | ssh_ed25519_equal(const struct sshkey *a, const struct sshkey *b) |
46 | 0 | { |
47 | 0 | if (a->ed25519_pk == NULL || b->ed25519_pk == NULL) |
48 | 0 | return 0; |
49 | 0 | if (memcmp(a->ed25519_pk, b->ed25519_pk, ED25519_PK_SZ) != 0) |
50 | 0 | return 0; |
51 | 0 | return 1; |
52 | 0 | } |
53 | | |
54 | | static int |
55 | | ssh_ed25519_serialize_public(const struct sshkey *key, struct sshbuf *b, |
56 | | enum sshkey_serialize_rep opts) |
57 | 0 | { |
58 | 0 | int r; |
59 | |
|
60 | 0 | if (key->ed25519_pk == NULL) |
61 | 0 | return SSH_ERR_INVALID_ARGUMENT; |
62 | 0 | if ((r = sshbuf_put_string(b, key->ed25519_pk, ED25519_PK_SZ)) != 0) |
63 | 0 | return r; |
64 | | |
65 | 0 | return 0; |
66 | 0 | } |
67 | | |
68 | | static int |
69 | | ssh_ed25519_serialize_private(const struct sshkey *key, struct sshbuf *b, |
70 | | enum sshkey_serialize_rep opts) |
71 | 0 | { |
72 | 0 | int r; |
73 | |
|
74 | 0 | if ((r = sshbuf_put_string(b, key->ed25519_pk, ED25519_PK_SZ)) != 0 || |
75 | 0 | (r = sshbuf_put_string(b, key->ed25519_sk, ED25519_SK_SZ)) != 0) |
76 | 0 | return r; |
77 | | |
78 | 0 | return 0; |
79 | 0 | } |
80 | | |
81 | | static int |
82 | | ssh_ed25519_generate(struct sshkey *k, int bits) |
83 | 0 | { |
84 | 0 | if ((k->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL || |
85 | 0 | (k->ed25519_sk = malloc(ED25519_SK_SZ)) == NULL) |
86 | 0 | return SSH_ERR_ALLOC_FAIL; |
87 | 0 | crypto_sign_ed25519_keypair(k->ed25519_pk, k->ed25519_sk); |
88 | 0 | return 0; |
89 | 0 | } |
90 | | |
91 | | static int |
92 | | ssh_ed25519_copy_public(const struct sshkey *from, struct sshkey *to) |
93 | 0 | { |
94 | 0 | if (from->ed25519_pk == NULL) |
95 | 0 | return 0; /* XXX SSH_ERR_INTERNAL_ERROR ? */ |
96 | 0 | if ((to->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL) |
97 | 0 | return SSH_ERR_ALLOC_FAIL; |
98 | 0 | memcpy(to->ed25519_pk, from->ed25519_pk, ED25519_PK_SZ); |
99 | 0 | return 0; |
100 | 0 | } |
101 | | |
102 | | static int |
103 | | ssh_ed25519_deserialize_public(const char *ktype, struct sshbuf *b, |
104 | | struct sshkey *key) |
105 | 2.39k | { |
106 | 2.39k | u_char *pk = NULL; |
107 | 2.39k | size_t len = 0; |
108 | 2.39k | int r; |
109 | | |
110 | 2.39k | if ((r = sshbuf_get_string(b, &pk, &len)) != 0) |
111 | 60 | return r; |
112 | 2.33k | if (len != ED25519_PK_SZ) { |
113 | 74 | freezero(pk, len); |
114 | 74 | return SSH_ERR_INVALID_FORMAT; |
115 | 74 | } |
116 | 2.25k | key->ed25519_pk = pk; |
117 | 2.25k | return 0; |
118 | 2.33k | } |
119 | | |
120 | | static int |
121 | | ssh_ed25519_deserialize_private(const char *ktype, struct sshbuf *b, |
122 | | struct sshkey *key) |
123 | 265 | { |
124 | 265 | int r; |
125 | 265 | size_t sklen = 0; |
126 | 265 | u_char *ed25519_sk = NULL; |
127 | | |
128 | 265 | if ((r = ssh_ed25519_deserialize_public(NULL, b, key)) != 0) |
129 | 106 | goto out; |
130 | 159 | if ((r = sshbuf_get_string(b, &ed25519_sk, &sklen)) != 0) |
131 | 7 | goto out; |
132 | 152 | if (sklen != ED25519_SK_SZ) { |
133 | 24 | r = SSH_ERR_INVALID_FORMAT; |
134 | 24 | goto out; |
135 | 24 | } |
136 | 128 | key->ed25519_sk = ed25519_sk; |
137 | 128 | ed25519_sk = NULL; /* transferred */ |
138 | | /* success */ |
139 | 128 | r = 0; |
140 | 265 | out: |
141 | 265 | freezero(ed25519_sk, sklen); |
142 | 265 | return r; |
143 | 128 | } |
144 | | |
145 | | static int |
146 | | ssh_ed25519_sign(struct sshkey *key, |
147 | | u_char **sigp, size_t *lenp, |
148 | | const u_char *data, size_t datalen, |
149 | | const char *alg, const char *sk_provider, const char *sk_pin, u_int compat) |
150 | 0 | { |
151 | 0 | u_char *sig = NULL; |
152 | 0 | size_t slen = 0; |
153 | 0 | unsigned long long smlen; |
154 | 0 | int r, ret; |
155 | |
|
156 | 0 | if (lenp != NULL) |
157 | 0 | *lenp = 0; |
158 | 0 | if (sigp != NULL) |
159 | 0 | *sigp = NULL; |
160 | |
|
161 | 0 | if (key == NULL || |
162 | 0 | sshkey_type_plain(key->type) != KEY_ED25519 || |
163 | 0 | key->ed25519_sk == NULL || |
164 | 0 | datalen >= INT_MAX - crypto_sign_ed25519_BYTES) |
165 | 0 | return SSH_ERR_INVALID_ARGUMENT; |
166 | 0 | smlen = slen = datalen + crypto_sign_ed25519_BYTES; |
167 | 0 | if ((sig = malloc(slen)) == NULL) |
168 | 0 | return SSH_ERR_ALLOC_FAIL; |
169 | | |
170 | 0 | if ((ret = crypto_sign_ed25519(sig, &smlen, data, datalen, |
171 | 0 | key->ed25519_sk)) != 0 || smlen <= datalen) { |
172 | 0 | r = SSH_ERR_INVALID_ARGUMENT; /* XXX better error? */ |
173 | 0 | goto out; |
174 | 0 | } |
175 | 0 | if ((r = ssh_ed25519_encode_store_sig(sig, smlen - datalen, |
176 | 0 | sigp, lenp)) != 0) |
177 | 0 | goto out; |
178 | | |
179 | | /* success */ |
180 | 0 | r = 0; |
181 | 0 | out: |
182 | 0 | freezero(sig, slen); |
183 | 0 | return r; |
184 | 0 | } |
185 | | |
186 | | int |
187 | | ssh_ed25519_encode_store_sig(const u_char *sig, size_t slen, |
188 | | u_char **sigp, size_t *lenp) |
189 | 0 | { |
190 | 0 | struct sshbuf *b = NULL; |
191 | 0 | int r = -1; |
192 | 0 | size_t len; |
193 | |
|
194 | 0 | if (lenp != NULL) |
195 | 0 | *lenp = 0; |
196 | 0 | if (sigp != NULL) |
197 | 0 | *sigp = NULL; |
198 | |
|
199 | 0 | if (slen != crypto_sign_ed25519_BYTES) |
200 | 0 | return SSH_ERR_INVALID_ARGUMENT; |
201 | | |
202 | | /* encode signature */ |
203 | 0 | if ((b = sshbuf_new()) == NULL) { |
204 | 0 | r = SSH_ERR_ALLOC_FAIL; |
205 | 0 | goto out; |
206 | 0 | } |
207 | 0 | if ((r = sshbuf_put_cstring(b, "ssh-ed25519")) != 0 || |
208 | 0 | (r = sshbuf_put_string(b, sig, slen)) != 0) |
209 | 0 | goto out; |
210 | 0 | len = sshbuf_len(b); |
211 | 0 | if (sigp != NULL) { |
212 | 0 | if ((*sigp = malloc(len)) == NULL) { |
213 | 0 | r = SSH_ERR_ALLOC_FAIL; |
214 | 0 | goto out; |
215 | 0 | } |
216 | 0 | memcpy(*sigp, sshbuf_ptr(b), len); |
217 | 0 | } |
218 | 0 | if (lenp != NULL) |
219 | 0 | *lenp = len; |
220 | | /* success */ |
221 | 0 | r = 0; |
222 | 0 | out: |
223 | 0 | sshbuf_free(b); |
224 | 0 | return r; |
225 | 0 | } |
226 | | |
227 | | static int |
228 | | ssh_ed25519_verify(const struct sshkey *key, |
229 | | const u_char *sig, size_t siglen, |
230 | | const u_char *data, size_t dlen, const char *alg, u_int compat, |
231 | | struct sshkey_sig_details **detailsp) |
232 | 179 | { |
233 | 179 | struct sshbuf *b = NULL; |
234 | 179 | char *ktype = NULL; |
235 | 179 | const u_char *sigblob; |
236 | 179 | u_char *sm = NULL, *m = NULL; |
237 | 179 | size_t len; |
238 | 179 | unsigned long long smlen = 0, mlen = 0; |
239 | 179 | int r, ret; |
240 | | |
241 | 179 | if (key == NULL || |
242 | 179 | sshkey_type_plain(key->type) != KEY_ED25519 || |
243 | 179 | key->ed25519_pk == NULL || |
244 | 179 | dlen >= INT_MAX - crypto_sign_ed25519_BYTES || |
245 | 179 | sig == NULL || siglen == 0) |
246 | 0 | return SSH_ERR_INVALID_ARGUMENT; |
247 | | |
248 | 179 | if ((b = sshbuf_from(sig, siglen)) == NULL) |
249 | 0 | return SSH_ERR_ALLOC_FAIL; |
250 | 179 | if ((r = sshbuf_get_cstring(b, &ktype, NULL)) != 0 || |
251 | 156 | (r = sshbuf_get_string_direct(b, &sigblob, &len)) != 0) |
252 | 25 | goto out; |
253 | 154 | if (strcmp("ssh-ed25519", ktype) != 0) { |
254 | 99 | r = SSH_ERR_KEY_TYPE_MISMATCH; |
255 | 99 | goto out; |
256 | 99 | } |
257 | 55 | if (sshbuf_len(b) != 0) { |
258 | 2 | r = SSH_ERR_UNEXPECTED_TRAILING_DATA; |
259 | 2 | goto out; |
260 | 2 | } |
261 | 53 | if (len > crypto_sign_ed25519_BYTES) { |
262 | 1 | r = SSH_ERR_INVALID_FORMAT; |
263 | 1 | goto out; |
264 | 1 | } |
265 | 52 | if (dlen >= SIZE_MAX - len) { |
266 | 0 | r = SSH_ERR_INVALID_ARGUMENT; |
267 | 0 | goto out; |
268 | 0 | } |
269 | 52 | smlen = len + dlen; |
270 | 52 | mlen = smlen; |
271 | 52 | if ((sm = malloc(smlen)) == NULL || (m = malloc(mlen)) == NULL) { |
272 | 0 | r = SSH_ERR_ALLOC_FAIL; |
273 | 0 | goto out; |
274 | 0 | } |
275 | 52 | memcpy(sm, sigblob, len); |
276 | 52 | memcpy(sm+len, data, dlen); |
277 | 52 | if ((ret = crypto_sign_ed25519_open(m, &mlen, sm, smlen, |
278 | 52 | key->ed25519_pk)) != 0) { |
279 | 50 | debug2_f("crypto_sign_ed25519_open failed: %d", ret); |
280 | 50 | } |
281 | 52 | if (ret != 0 || mlen != dlen) { |
282 | 52 | r = SSH_ERR_SIGNATURE_INVALID; |
283 | 52 | goto out; |
284 | 52 | } |
285 | | /* XXX compare 'm' and 'data' ? */ |
286 | | /* success */ |
287 | 0 | r = 0; |
288 | 179 | out: |
289 | 179 | if (sm != NULL) |
290 | 52 | freezero(sm, smlen); |
291 | 179 | if (m != NULL) |
292 | 52 | freezero(m, smlen); /* NB mlen may be invalid if r != 0 */ |
293 | 179 | sshbuf_free(b); |
294 | 179 | free(ktype); |
295 | 179 | return r; |
296 | 0 | } |
297 | | |
298 | | /* NB. not static; used by ED25519-SK */ |
299 | | const struct sshkey_impl_funcs sshkey_ed25519_funcs = { |
300 | | /* .size = */ NULL, |
301 | | /* .alloc = */ NULL, |
302 | | /* .cleanup = */ ssh_ed25519_cleanup, |
303 | | /* .equal = */ ssh_ed25519_equal, |
304 | | /* .ssh_serialize_public = */ ssh_ed25519_serialize_public, |
305 | | /* .ssh_deserialize_public = */ ssh_ed25519_deserialize_public, |
306 | | /* .ssh_serialize_private = */ ssh_ed25519_serialize_private, |
307 | | /* .ssh_deserialize_private = */ ssh_ed25519_deserialize_private, |
308 | | /* .generate = */ ssh_ed25519_generate, |
309 | | /* .copy_public = */ ssh_ed25519_copy_public, |
310 | | /* .sign = */ ssh_ed25519_sign, |
311 | | /* .verify = */ ssh_ed25519_verify, |
312 | | }; |
313 | | |
314 | | const struct sshkey_impl sshkey_ed25519_impl = { |
315 | | /* .name = */ "ssh-ed25519", |
316 | | /* .shortname = */ "ED25519", |
317 | | /* .sigalg = */ NULL, |
318 | | /* .type = */ KEY_ED25519, |
319 | | /* .nid = */ 0, |
320 | | /* .cert = */ 0, |
321 | | /* .sigonly = */ 0, |
322 | | /* .keybits = */ 256, |
323 | | /* .funcs = */ &sshkey_ed25519_funcs, |
324 | | }; |
325 | | |
326 | | const struct sshkey_impl sshkey_ed25519_cert_impl = { |
327 | | /* .name = */ "ssh-ed25519-cert-v01@openssh.com", |
328 | | /* .shortname = */ "ED25519-CERT", |
329 | | /* .sigalg = */ NULL, |
330 | | /* .type = */ KEY_ED25519_CERT, |
331 | | /* .nid = */ 0, |
332 | | /* .cert = */ 1, |
333 | | /* .sigonly = */ 0, |
334 | | /* .keybits = */ 256, |
335 | | /* .funcs = */ &sshkey_ed25519_funcs, |
336 | | }; |