/src/hpn-ssh/ssh-ed25519.c

Source
/* $OpenBSD: ssh-ed25519.c,v 1.24 2026/09/16 00:43:00 djm Exp $ */
/*
 * Copyright (c) 2013 Markus Friedl <markus@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "includes.h"

#include <sys/types.h>
#include <limits.h>

#include "crypto_api.h"

#include <string.h>
#include <stdarg.h>

#include "log.h"
#include "sshbuf.h"
#define SSHKEY_INTERNAL
#include "sshkey.h"
#include "ssherr.h"

static void
ssh_ed25519_cleanup(struct sshkey *k)
{
  freezero(k->ed25519_pk, ED25519_PK_SZ);
  freezero(k->ed25519_sk, ED25519_SK_SZ);
  k->ed25519_pk = NULL;
  k->ed25519_sk = NULL;
}

static int
ssh_ed25519_equal(const struct sshkey *a, const struct sshkey *b)
{
  if (a->ed25519_pk == NULL || b->ed25519_pk == NULL)
    return 0;
  if (memcmp(a->ed25519_pk, b->ed25519_pk, ED25519_PK_SZ) != 0)
    return 0;
  return 1;
}

static int
ssh_ed25519_serialize_public(const struct sshkey *key, struct sshbuf *b,
    enum sshkey_serialize_rep opts)
{
  int r;

  if (key->ed25519_pk == NULL)
    return SSH_ERR_INVALID_ARGUMENT;
  if ((r = sshbuf_put_string(b, key->ed25519_pk, ED25519_PK_SZ)) != 0)
    return r;

  return 0;
}

static int
ssh_ed25519_serialize_private(const struct sshkey *key, struct sshbuf *b,
    enum sshkey_serialize_rep opts)
{
  int r;

  if ((r = sshbuf_put_string(b, key->ed25519_pk, ED25519_PK_SZ)) != 0 ||
      (r = sshbuf_put_string(b, key->ed25519_sk, ED25519_SK_SZ)) != 0)
    return r;

  return 0;
}

static int
ssh_ed25519_generate(struct sshkey *k, int bits)
{
  if ((k->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL ||
      (k->ed25519_sk = malloc(ED25519_SK_SZ)) == NULL)
    return SSH_ERR_ALLOC_FAIL;
  if (crypto_sign_ed25519_keypair(k->ed25519_pk, k->ed25519_sk) != 0)
    return SSH_ERR_CRYPTO_ERROR;
  return 0;
}

static int
ssh_ed25519_copy_public(const struct sshkey *from, struct sshkey *to)
{
  if (from->ed25519_pk == NULL)
    return 0; /* XXX SSH_ERR_INTERNAL_ERROR ? */
  if ((to->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL)
    return SSH_ERR_ALLOC_FAIL;
  memcpy(to->ed25519_pk, from->ed25519_pk, ED25519_PK_SZ);
  return 0;
}

static int
ssh_ed25519_deserialize_public(const char *ktype, struct sshbuf *b,
    struct sshkey *key)
{
  u_char *pk = NULL;
  size_t len = 0;
  int r;

  if ((r = sshbuf_get_string(b, &pk, &len)) != 0)
    return r;
  if (len != ED25519_PK_SZ) {
    freezero(pk, len);
    return SSH_ERR_INVALID_FORMAT;
  }
  key->ed25519_pk = pk;
  return 0;
}

static int
ssh_ed25519_deserialize_private(const char *ktype, struct sshbuf *b,
    struct sshkey *key)
{
  int r;
  size_t sklen = 0;
  u_char *ed25519_sk = NULL;

  if ((r = ssh_ed25519_deserialize_public(NULL, b, key)) != 0)
    goto out;
  if ((r = sshbuf_get_string(b, &ed25519_sk, &sklen)) != 0)
    goto out;
  if (sklen != ED25519_SK_SZ) {
    r = SSH_ERR_INVALID_FORMAT;
    goto out;
  }
  key->ed25519_sk = ed25519_sk;
  ed25519_sk = NULL; /* transferred */
  /* success */
  r = 0;
 out:
  freezero(ed25519_sk, sklen);
  return r;
}

static int
ssh_ed25519_sign(struct sshkey *key,
    u_char **sigp, size_t *lenp,
    const u_char *data, size_t datalen,
    const char *alg, const char *sk_provider, const char *sk_pin, u_int compat)
{
  u_char sig[crypto_sign_ed25519_BYTES];
  unsigned long long siglen = 0;
  int r, ret;

  if (lenp != NULL)
    *lenp = 0;
  if (sigp != NULL)
    *sigp = NULL;

  if (key == NULL ||
      sshkey_type_plain(key->type) != KEY_ED25519 ||
      key->ed25519_sk == NULL)
    return SSH_ERR_INVALID_ARGUMENT;

  if ((ret = crypto_sign_ed25519_detached(sig, &siglen, data, datalen,
      key->ed25519_sk)) != 0 || siglen != sizeof(sig)) {
    r = SSH_ERR_INVALID_ARGUMENT; /* XXX better error? */
    goto out;
  }
  if ((r = ssh_ed25519_encode_store_sig(sig, siglen,
      sigp, lenp)) != 0)
    goto out;

  /* success */
  r = 0;
 out:
  explicit_bzero(sig, sizeof(sig));
  return r;
}

int
ssh_ed25519_encode_store_sig(const u_char *sig, size_t slen,
    u_char **sigp, size_t *lenp)
{
  struct sshbuf *b = NULL;
  int r = -1;
  size_t len;

  if (lenp != NULL)
    *lenp = 0;
  if (sigp != NULL)
    *sigp = NULL;

  if (slen != crypto_sign_ed25519_BYTES)
    return SSH_ERR_INVALID_ARGUMENT;

  /* encode signature */
  if ((b = sshbuf_new()) == NULL) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  if ((r = sshbuf_put_cstring(b, "ssh-ed25519")) != 0 ||
      (r = sshbuf_put_string(b, sig, slen)) != 0)
    goto out;
  len = sshbuf_len(b);
  if (sigp != NULL) {
    if ((*sigp = malloc(len)) == NULL) {
      r = SSH_ERR_ALLOC_FAIL;
      goto out;
    }
    memcpy(*sigp, sshbuf_ptr(b), len);
  }
  if (lenp != NULL)
    *lenp = len;
  /* success */
  r = 0;
 out:
  sshbuf_free(b);
  return r;
}

static int
ssh_ed25519_verify(const struct sshkey *key,
    const u_char *sig, size_t siglen,
    const u_char *data, size_t dlen, const char *alg, u_int compat,
    struct sshkey_sig_details **detailsp)
{
  struct sshbuf *b = NULL;
  char *ktype = NULL;
  const u_char *sigblob;
  size_t len;
  int r, ret;

  if (key == NULL ||
      sshkey_type_plain(key->type) != KEY_ED25519 ||
      key->ed25519_pk == NULL ||
      sig == NULL || siglen == 0)
    return SSH_ERR_INVALID_ARGUMENT;

  if ((b = sshbuf_from(sig, siglen)) == NULL)
    return SSH_ERR_ALLOC_FAIL;
  if ((r = sshbuf_get_cstring(b, &ktype, NULL)) != 0 ||
      (r = sshbuf_get_string_direct(b, &sigblob, &len)) != 0)
    goto out;
  if (strcmp("ssh-ed25519", ktype) != 0) {
    r = SSH_ERR_KEY_TYPE_MISMATCH;
    goto out;
  }
  if (sshbuf_len(b) != 0) {
    r = SSH_ERR_UNEXPECTED_TRAILING_DATA;
    goto out;
  }
  if (len != crypto_sign_ed25519_BYTES) {
    r = SSH_ERR_INVALID_FORMAT;
    goto out;
  }
  if ((ret = crypto_sign_ed25519_verify_detached(sigblob, data, dlen,
      key->ed25519_pk)) != 0) {
    debug2_f("crypto_sign_ed25519_verify_detached failed: %d", ret);
  }
  if (ret != 0) {
    r = SSH_ERR_SIGNATURE_INVALID;
    goto out;
  }
  /* success */
  r = 0;
 out:
  sshbuf_free(b);
  free(ktype);
  return r;
}

/* NB. not static; used by ED25519-SK */
const struct sshkey_impl_funcs sshkey_ed25519_funcs = {
  /* .size = */   NULL,
  /* .alloc = */    NULL,
  /* .cleanup = */  ssh_ed25519_cleanup,
  /* .equal = */    ssh_ed25519_equal,
  /* .ssh_serialize_public = */ ssh_ed25519_serialize_public,
  /* .ssh_deserialize_public = */ ssh_ed25519_deserialize_public,
  /* .ssh_serialize_private = */ ssh_ed25519_serialize_private,
  /* .ssh_deserialize_private = */ ssh_ed25519_deserialize_private,
  /* .generate = */ ssh_ed25519_generate,
  /* .copy_public = */  ssh_ed25519_copy_public,
  /* .sign = */   ssh_ed25519_sign,
  /* .verify = */   ssh_ed25519_verify,
};

const struct sshkey_impl sshkey_ed25519_impl = {
  /* .name = */   "ssh-ed25519",
  /* .shortname = */  "ED25519",
  /* .sigalg = */   NULL,
  /* .type = */   KEY_ED25519,
  /* .nid = */    0,
  /* .cert = */   0,
  /* .sigonly = */  0,
  /* .keybits = */  256,
  /* .funcs = */    &sshkey_ed25519_funcs,
};

const struct sshkey_impl sshkey_ed25519_cert_impl = {
  /* .name = */   "ssh-ed25519-cert-v01@openssh.com",
  /* .shortname = */  "ED25519-CERT",
  /* .sigalg = */   NULL,
  /* .type = */   KEY_ED25519_CERT,
  /* .nid = */    0,
  /* .cert = */   1,
  /* .sigonly = */  0,
  /* .keybits = */  256,
  /* .funcs = */    &sshkey_ed25519_funcs,
};

Coverage Report

Created: 2026-10-17 06:48

Line	Count	Source
1		/* $OpenBSD: ssh-ed25519.c,v 1.24 2026/09/16 00:43:00 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
34		static void
35		ssh_ed25519_cleanup(struct sshkey *k)
36	0	{
37	0	freezero(k->ed25519_pk, ED25519_PK_SZ);
38	0	freezero(k->ed25519_sk, ED25519_SK_SZ);
39	0	k->ed25519_pk = NULL;
40	0	k->ed25519_sk = NULL;
41	0	}
42
43		static int
44		ssh_ed25519_equal(const struct sshkey a, const struct sshkey b)
45	0	{
46	0	if (a->ed25519_pk == NULL \|\| b->ed25519_pk == NULL)
47	0	return 0;
48	0	if (memcmp(a->ed25519_pk, b->ed25519_pk, ED25519_PK_SZ) != 0)
49	0	return 0;
50	0	return 1;
51	0	}
52
53		static int
54		ssh_ed25519_serialize_public(const struct sshkey key, struct sshbuf b,
55		enum sshkey_serialize_rep opts)
56	0	{
57	0	int r;
58
59	0	if (key->ed25519_pk == NULL)
60	0	return SSH_ERR_INVALID_ARGUMENT;
61	0	if ((r = sshbuf_put_string(b, key->ed25519_pk, ED25519_PK_SZ)) != 0)
62	0	return r;
63
64	0	return 0;
65	0	}
66
67		static int
68		ssh_ed25519_serialize_private(const struct sshkey key, struct sshbuf b,
69		enum sshkey_serialize_rep opts)
70	0	{
71	0	int r;
72
73	0	if ((r = sshbuf_put_string(b, key->ed25519_pk, ED25519_PK_SZ)) != 0 \|\|
74	0	(r = sshbuf_put_string(b, key->ed25519_sk, ED25519_SK_SZ)) != 0)
75	0	return r;
76
77	0	return 0;
78	0	}
79
80		static int
81		ssh_ed25519_generate(struct sshkey *k, int bits)
82	1	{
83	1	if ((k->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL \|\|
84	1	(k->ed25519_sk = malloc(ED25519_SK_SZ)) == NULL)
85	0	return SSH_ERR_ALLOC_FAIL;
86	1	if (crypto_sign_ed25519_keypair(k->ed25519_pk, k->ed25519_sk) != 0)
87	0	return SSH_ERR_CRYPTO_ERROR;
88	1	return 0;
89	1	}
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	0	{
106	0	u_char *pk = NULL;
107	0	size_t len = 0;
108	0	int r;
109
110	0	if ((r = sshbuf_get_string(b, &pk, &len)) != 0)
111	0	return r;
112	0	if (len != ED25519_PK_SZ) {
113	0	freezero(pk, len);
114	0	return SSH_ERR_INVALID_FORMAT;
115	0	}
116	0	key->ed25519_pk = pk;
117	0	return 0;
118	0	}
119
120		static int
121		ssh_ed25519_deserialize_private(const char ktype, struct sshbuf b,
122		struct sshkey *key)
123	0	{
124	0	int r;
125	0	size_t sklen = 0;
126	0	u_char *ed25519_sk = NULL;
127
128	0	if ((r = ssh_ed25519_deserialize_public(NULL, b, key)) != 0)
129	0	goto out;
130	0	if ((r = sshbuf_get_string(b, &ed25519_sk, &sklen)) != 0)
131	0	goto out;
132	0	if (sklen != ED25519_SK_SZ) {
133	0	r = SSH_ERR_INVALID_FORMAT;
134	0	goto out;
135	0	}
136	0	key->ed25519_sk = ed25519_sk;
137	0	ed25519_sk = NULL; /* transferred */
138		/* success */
139	0	r = 0;
140	0	out:
141	0	freezero(ed25519_sk, sklen);
142	0	return r;
143	0	}
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[crypto_sign_ed25519_BYTES];
152	0	unsigned long long siglen = 0;
153	0	int r, ret;
154
155	0	if (lenp != NULL)
156	0	*lenp = 0;
157	0	if (sigp != NULL)
158	0	*sigp = NULL;
159
160	0	if (key == NULL \|\|
161	0	sshkey_type_plain(key->type) != KEY_ED25519 \|\|
162	0	key->ed25519_sk == NULL)
163	0	return SSH_ERR_INVALID_ARGUMENT;
164
165	0	if ((ret = crypto_sign_ed25519_detached(sig, &siglen, data, datalen,
166	0	key->ed25519_sk)) != 0 \|\| siglen != sizeof(sig)) {
167	0	r = SSH_ERR_INVALID_ARGUMENT; /* XXX better error? */
168	0	goto out;
169	0	}
170	0	if ((r = ssh_ed25519_encode_store_sig(sig, siglen,
171	0	sigp, lenp)) != 0)
172	0	goto out;
173
174		/* success */
175	0	r = 0;
176	0	out:
177	0	explicit_bzero(sig, sizeof(sig));
178	0	return r;
179	0	}
180
181		int
182		ssh_ed25519_encode_store_sig(const u_char *sig, size_t slen,
183		u_char *sigp, size_t lenp)
184	0	{
185	0	struct sshbuf *b = NULL;
186	0	int r = -1;
187	0	size_t len;
188
189	0	if (lenp != NULL)
190	0	*lenp = 0;
191	0	if (sigp != NULL)
192	0	*sigp = NULL;
193
194	0	if (slen != crypto_sign_ed25519_BYTES)
195	0	return SSH_ERR_INVALID_ARGUMENT;
196
197		/* encode signature */
198	0	if ((b = sshbuf_new()) == NULL) {
199	0	r = SSH_ERR_ALLOC_FAIL;
200	0	goto out;
201	0	}
202	0	if ((r = sshbuf_put_cstring(b, "ssh-ed25519")) != 0 \|\|
203	0	(r = sshbuf_put_string(b, sig, slen)) != 0)
204	0	goto out;
205	0	len = sshbuf_len(b);
206	0	if (sigp != NULL) {
207	0	if ((*sigp = malloc(len)) == NULL) {
208	0	r = SSH_ERR_ALLOC_FAIL;
209	0	goto out;
210	0	}
211	0	memcpy(*sigp, sshbuf_ptr(b), len);
212	0	}
213	0	if (lenp != NULL)
214	0	*lenp = len;
215		/* success */
216	0	r = 0;
217	0	out:
218	0	sshbuf_free(b);
219	0	return r;
220	0	}
221
222		static int
223		ssh_ed25519_verify(const struct sshkey *key,
224		const u_char *sig, size_t siglen,
225		const u_char data, size_t dlen, const char alg, u_int compat,
226		struct sshkey_sig_details **detailsp)
227	1.17k	{
228	1.17k	struct sshbuf *b = NULL;
229	1.17k	char *ktype = NULL;
230	1.17k	const u_char *sigblob;
231	1.17k	size_t len;
232	1.17k	int r, ret;
233
234	1.17k	if (key == NULL \|\|
235	1.17k	sshkey_type_plain(key->type) != KEY_ED25519 \|\|
236	1.17k	key->ed25519_pk == NULL \|\|
237	1.17k	sig == NULL \|\| siglen == 0)
238	0	return SSH_ERR_INVALID_ARGUMENT;
239
240	1.17k	if ((b = sshbuf_from(sig, siglen)) == NULL)
241	0	return SSH_ERR_ALLOC_FAIL;
242	1.17k	if ((r = sshbuf_get_cstring(b, &ktype, NULL)) != 0 \|\|
243	1.10k	(r = sshbuf_get_string_direct(b, &sigblob, &len)) != 0)
244	469	goto out;
245	701	if (strcmp("ssh-ed25519", ktype) != 0) {
246	657	r = SSH_ERR_KEY_TYPE_MISMATCH;
247	657	goto out;
248	657	}
249	44	if (sshbuf_len(b) != 0) {
250	21	r = SSH_ERR_UNEXPECTED_TRAILING_DATA;
251	21	goto out;
252	21	}
253	23	if (len != crypto_sign_ed25519_BYTES) {
254	22	r = SSH_ERR_INVALID_FORMAT;
255	22	goto out;
256	22	}
257	1	if ((ret = crypto_sign_ed25519_verify_detached(sigblob, data, dlen,
258	1	key->ed25519_pk)) != 0) {
259	1	debug2_f("crypto_sign_ed25519_verify_detached failed: %d", ret);
260	1	}
261	1	if (ret != 0) {
262	1	r = SSH_ERR_SIGNATURE_INVALID;
263	1	goto out;
264	1	}
265		/* success */
266	0	r = 0;
267	1.17k	out:
268	1.17k	sshbuf_free(b);
269	1.17k	free(ktype);
270	1.17k	return r;
271	0	}
272
273		/* NB. not static; used by ED25519-SK */
274		const struct sshkey_impl_funcs sshkey_ed25519_funcs = {
275		/* .size = */ NULL,
276		/* .alloc = */ NULL,
277		/* .cleanup = */ ssh_ed25519_cleanup,
278		/* .equal = */ ssh_ed25519_equal,
279		/* .ssh_serialize_public = */ ssh_ed25519_serialize_public,
280		/* .ssh_deserialize_public = */ ssh_ed25519_deserialize_public,
281		/* .ssh_serialize_private = */ ssh_ed25519_serialize_private,
282		/* .ssh_deserialize_private = */ ssh_ed25519_deserialize_private,
283		/* .generate = */ ssh_ed25519_generate,
284		/* .copy_public = */ ssh_ed25519_copy_public,
285		/* .sign = */ ssh_ed25519_sign,
286		/* .verify = */ ssh_ed25519_verify,
287		};
288
289		const struct sshkey_impl sshkey_ed25519_impl = {
290		/* .name = */ "ssh-ed25519",
291		/* .shortname = */ "ED25519",
292		/* .sigalg = */ NULL,
293		/* .type = */ KEY_ED25519,
294		/* .nid = */ 0,
295		/* .cert = */ 0,
296		/* .sigonly = */ 0,
297		/* .keybits = */ 256,
298		/* .funcs = */ &sshkey_ed25519_funcs,
299		};
300
301		const struct sshkey_impl sshkey_ed25519_cert_impl = {
302		/* .name = */ "ssh-ed25519-cert-v01@openssh.com",
303		/* .shortname = */ "ED25519-CERT",
304		/* .sigalg = */ NULL,
305		/* .type = */ KEY_ED25519_CERT,
306		/* .nid = */ 0,
307		/* .cert = */ 1,
308		/* .sigonly = */ 0,
309		/* .keybits = */ 256,
310		/* .funcs = */ &sshkey_ed25519_funcs,
311		};