Coverage Report

Created: 2025-07-02 06:55

/src/openssh/ssh-ed25519.c
Line
Count
Source (jump to first uncovered line)
1
/* $OpenBSD: ssh-ed25519.c,v 1.19 2022/10/28 00:44:44 djm Exp $ */
2
/*
3
 * Copyright (c) 2013 Markus Friedl <markus@openbsd.org>
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 *
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 * Permission to use, copy, modify, and distribute this software for any
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 * purpose with or without fee is hereby granted, provided that the above
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 * copyright notice and this permission notice appear in all copies.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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 */
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18
#include "includes.h"
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20
#include <sys/types.h>
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#include <limits.h>
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23
#include "crypto_api.h"
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25
#include <string.h>
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#include <stdarg.h>
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28
#include "log.h"
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#include "sshbuf.h"
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#define SSHKEY_INTERNAL
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#include "sshkey.h"
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#include "ssherr.h"
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#include "ssh.h"
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35
static void
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ssh_ed25519_cleanup(struct sshkey *k)
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1.05k
{
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1.05k
  freezero(k->ed25519_pk, ED25519_PK_SZ);
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1.05k
  freezero(k->ed25519_sk, ED25519_SK_SZ);
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1.05k
  k->ed25519_pk = NULL;
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1.05k
  k->ed25519_sk = NULL;
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1.05k
}
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44
static int
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ssh_ed25519_equal(const struct sshkey *a, const struct sshkey *b)
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0
{
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0
  if (a->ed25519_pk == NULL || b->ed25519_pk == NULL)
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0
    return 0;
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0
  if (memcmp(a->ed25519_pk, b->ed25519_pk, ED25519_PK_SZ) != 0)
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0
    return 0;
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0
  return 1;
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0
}
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54
static int
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ssh_ed25519_serialize_public(const struct sshkey *key, struct sshbuf *b,
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    enum sshkey_serialize_rep opts)
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0
{
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0
  int r;
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60
0
  if (key->ed25519_pk == NULL)
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0
    return SSH_ERR_INVALID_ARGUMENT;
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0
  if ((r = sshbuf_put_string(b, key->ed25519_pk, ED25519_PK_SZ)) != 0)
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0
    return r;
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65
0
  return 0;
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0
}
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static int
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ssh_ed25519_serialize_private(const struct sshkey *key, struct sshbuf *b,
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    enum sshkey_serialize_rep opts)
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0
{
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0
  int r;
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74
0
  if ((r = sshbuf_put_string(b, key->ed25519_pk, ED25519_PK_SZ)) != 0 ||
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0
      (r = sshbuf_put_string(b, key->ed25519_sk, ED25519_SK_SZ)) != 0)
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0
    return r;
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78
0
  return 0;
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0
}
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81
static int
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ssh_ed25519_generate(struct sshkey *k, int bits)
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0
{
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0
  if ((k->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL ||
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0
      (k->ed25519_sk = malloc(ED25519_SK_SZ)) == NULL)
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0
    return SSH_ERR_ALLOC_FAIL;
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0
  crypto_sign_ed25519_keypair(k->ed25519_pk, k->ed25519_sk);
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0
  return 0;
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0
}
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91
static int
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ssh_ed25519_copy_public(const struct sshkey *from, struct sshkey *to)
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0
{
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0
  if (from->ed25519_pk == NULL)
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0
    return 0; /* XXX SSH_ERR_INTERNAL_ERROR ? */
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0
  if ((to->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL)
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0
    return SSH_ERR_ALLOC_FAIL;
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0
  memcpy(to->ed25519_pk, from->ed25519_pk, ED25519_PK_SZ);
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0
  return 0;
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0
}
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102
static int
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ssh_ed25519_deserialize_public(const char *ktype, struct sshbuf *b,
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    struct sshkey *key)
105
1.05k
{
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1.05k
  u_char *pk = NULL;
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1.05k
  size_t len = 0;
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1.05k
  int r;
109
110
1.05k
  if ((r = sshbuf_get_string(b, &pk, &len)) != 0)
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4
    return r;
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1.04k
  if (len != ED25519_PK_SZ) {
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22
    freezero(pk, len);
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22
    return SSH_ERR_INVALID_FORMAT;
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22
  }
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1.02k
  key->ed25519_pk = pk;
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1.02k
  return 0;
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1.04k
}
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120
static int
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ssh_ed25519_deserialize_private(const char *ktype, struct sshbuf *b,
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    struct sshkey *key)
123
0
{
124
0
  int r;
125
0
  size_t sklen = 0;
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0
  u_char *ed25519_sk = NULL;
127
128
0
  if ((r = ssh_ed25519_deserialize_public(NULL, b, key)) != 0)
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0
    goto out;
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0
  if ((r = sshbuf_get_string(b, &ed25519_sk, &sklen)) != 0)
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0
    goto out;
132
0
  if (sklen != ED25519_SK_SZ) {
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0
    r = SSH_ERR_INVALID_FORMAT;
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0
    goto out;
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0
  }
136
0
  key->ed25519_sk = ed25519_sk;
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0
  ed25519_sk = NULL; /* transferred */
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  /* success */
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0
  r = 0;
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0
 out:
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0
  freezero(ed25519_sk, sklen);
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0
  return r;
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0
}
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static int
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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, len;
153
0
  unsigned long long smlen;
154
0
  int r, ret;
155
0
  struct sshbuf *b = NULL;
156
157
0
  if (lenp != NULL)
158
0
    *lenp = 0;
159
0
  if (sigp != NULL)
160
0
    *sigp = NULL;
161
162
0
  if (key == NULL ||
163
0
      sshkey_type_plain(key->type) != KEY_ED25519 ||
164
0
      key->ed25519_sk == NULL ||
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0
      datalen >= INT_MAX - crypto_sign_ed25519_BYTES)
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0
    return SSH_ERR_INVALID_ARGUMENT;
167
0
  smlen = slen = datalen + crypto_sign_ed25519_BYTES;
168
0
  if ((sig = malloc(slen)) == NULL)
169
0
    return SSH_ERR_ALLOC_FAIL;
170
171
0
  if ((ret = crypto_sign_ed25519(sig, &smlen, data, datalen,
172
0
      key->ed25519_sk)) != 0 || smlen <= datalen) {
173
0
    r = SSH_ERR_INVALID_ARGUMENT; /* XXX better error? */
174
0
    goto out;
175
0
  }
176
  /* encode signature */
177
0
  if ((b = sshbuf_new()) == NULL) {
178
0
    r = SSH_ERR_ALLOC_FAIL;
179
0
    goto out;
180
0
  }
181
0
  if ((r = sshbuf_put_cstring(b, "ssh-ed25519")) != 0 ||
182
0
      (r = sshbuf_put_string(b, sig, smlen - datalen)) != 0)
183
0
    goto out;
184
0
  len = sshbuf_len(b);
185
0
  if (sigp != NULL) {
186
0
    if ((*sigp = malloc(len)) == NULL) {
187
0
      r = SSH_ERR_ALLOC_FAIL;
188
0
      goto out;
189
0
    }
190
0
    memcpy(*sigp, sshbuf_ptr(b), len);
191
0
  }
192
0
  if (lenp != NULL)
193
0
    *lenp = len;
194
  /* success */
195
0
  r = 0;
196
0
 out:
197
0
  sshbuf_free(b);
198
0
  if (sig != NULL)
199
0
    freezero(sig, slen);
200
201
0
  return r;
202
0
}
203
204
static int
205
ssh_ed25519_verify(const struct sshkey *key,
206
    const u_char *sig, size_t siglen,
207
    const u_char *data, size_t dlen, const char *alg, u_int compat,
208
    struct sshkey_sig_details **detailsp)
209
198
{
210
198
  struct sshbuf *b = NULL;
211
198
  char *ktype = NULL;
212
198
  const u_char *sigblob;
213
198
  u_char *sm = NULL, *m = NULL;
214
198
  size_t len;
215
198
  unsigned long long smlen = 0, mlen = 0;
216
198
  int r, ret;
217
218
198
  if (key == NULL ||
219
198
      sshkey_type_plain(key->type) != KEY_ED25519 ||
220
198
      key->ed25519_pk == NULL ||
221
198
      dlen >= INT_MAX - crypto_sign_ed25519_BYTES ||
222
198
      sig == NULL || siglen == 0)
223
0
    return SSH_ERR_INVALID_ARGUMENT;
224
225
198
  if ((b = sshbuf_from(sig, siglen)) == NULL)
226
0
    return SSH_ERR_ALLOC_FAIL;
227
198
  if ((r = sshbuf_get_cstring(b, &ktype, NULL)) != 0 ||
228
198
      (r = sshbuf_get_string_direct(b, &sigblob, &len)) != 0)
229
25
    goto out;
230
173
  if (strcmp("ssh-ed25519", ktype) != 0) {
231
99
    r = SSH_ERR_KEY_TYPE_MISMATCH;
232
99
    goto out;
233
99
  }
234
74
  if (sshbuf_len(b) != 0) {
235
16
    r = SSH_ERR_UNEXPECTED_TRAILING_DATA;
236
16
    goto out;
237
16
  }
238
58
  if (len > crypto_sign_ed25519_BYTES) {
239
1
    r = SSH_ERR_INVALID_FORMAT;
240
1
    goto out;
241
1
  }
242
57
  if (dlen >= SIZE_MAX - len) {
243
0
    r = SSH_ERR_INVALID_ARGUMENT;
244
0
    goto out;
245
0
  }
246
57
  smlen = len + dlen;
247
57
  mlen = smlen;
248
57
  if ((sm = malloc(smlen)) == NULL || (m = malloc(mlen)) == NULL) {
249
0
    r = SSH_ERR_ALLOC_FAIL;
250
0
    goto out;
251
0
  }
252
57
  memcpy(sm, sigblob, len);
253
57
  memcpy(sm+len, data, dlen);
254
57
  if ((ret = crypto_sign_ed25519_open(m, &mlen, sm, smlen,
255
57
      key->ed25519_pk)) != 0) {
256
57
    debug2_f("crypto_sign_ed25519_open failed: %d", ret);
257
57
  }
258
57
  if (ret != 0 || mlen != dlen) {
259
57
    r = SSH_ERR_SIGNATURE_INVALID;
260
57
    goto out;
261
57
  }
262
  /* XXX compare 'm' and 'data' ? */
263
  /* success */
264
0
  r = 0;
265
198
 out:
266
198
  if (sm != NULL)
267
57
    freezero(sm, smlen);
268
198
  if (m != NULL)
269
57
    freezero(m, smlen); /* NB mlen may be invalid if r != 0 */
270
198
  sshbuf_free(b);
271
198
  free(ktype);
272
198
  return r;
273
0
}
274
275
/* NB. not static; used by ED25519-SK */
276
const struct sshkey_impl_funcs sshkey_ed25519_funcs = {
277
  /* .size = */   NULL,
278
  /* .alloc = */    NULL,
279
  /* .cleanup = */  ssh_ed25519_cleanup,
280
  /* .equal = */    ssh_ed25519_equal,
281
  /* .ssh_serialize_public = */ ssh_ed25519_serialize_public,
282
  /* .ssh_deserialize_public = */ ssh_ed25519_deserialize_public,
283
  /* .ssh_serialize_private = */ ssh_ed25519_serialize_private,
284
  /* .ssh_deserialize_private = */ ssh_ed25519_deserialize_private,
285
  /* .generate = */ ssh_ed25519_generate,
286
  /* .copy_public = */  ssh_ed25519_copy_public,
287
  /* .sign = */   ssh_ed25519_sign,
288
  /* .verify = */   ssh_ed25519_verify,
289
};
290
291
const struct sshkey_impl sshkey_ed25519_impl = {
292
  /* .name = */   "ssh-ed25519",
293
  /* .shortname = */  "ED25519",
294
  /* .sigalg = */   NULL,
295
  /* .type = */   KEY_ED25519,
296
  /* .nid = */    0,
297
  /* .cert = */   0,
298
  /* .sigonly = */  0,
299
  /* .keybits = */  256,
300
  /* .funcs = */    &sshkey_ed25519_funcs,
301
};
302
303
const struct sshkey_impl sshkey_ed25519_cert_impl = {
304
  /* .name = */   "ssh-ed25519-cert-v01@openssh.com",
305
  /* .shortname = */  "ED25519-CERT",
306
  /* .sigalg = */   NULL,
307
  /* .type = */   KEY_ED25519_CERT,
308
  /* .nid = */    0,
309
  /* .cert = */   1,
310
  /* .sigonly = */  0,
311
  /* .keybits = */  256,
312
  /* .funcs = */    &sshkey_ed25519_funcs,
313
};