1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
|
/* $OpenBSD: ed25519-openssl.c,v 1.3 2026/06/29 02:08:55 djm Exp $ */
/*
* Copyright (c) 2025 OpenSSH
*
* 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.
*/
/*
* OpenSSL-based implementation of Ed25519 crypto_sign API
* Alternative to the internal SUPERCOP-based implementation in ed25519.c
*/
#include "includes.h"
#ifdef OPENSSL_HAS_ED25519
#include <sys/types.h>
#include <string.h>
#include <stdint.h>
#include <limits.h>
#include <openssl/evp.h>
#include "crypto_api.h"
#include "log.h"
#if crypto_sign_ed25519_SECRETKEYBYTES <= crypto_sign_ed25519_PUBLICKEYBYTES
#error "crypto_sign_ed25519_SECRETKEYBYTES < crypto_sign_ed25519_PUBLICKEYBYTES"
#endif
#define SSH_ED25519_RAW_SECRET_KEY_LEN \
(crypto_sign_ed25519_SECRETKEYBYTES - crypto_sign_ed25519_PUBLICKEYBYTES)
int
crypto_sign_ed25519_keypair(unsigned char *pk, unsigned char *sk)
{
EVP_PKEY_CTX *ctx = NULL;
EVP_PKEY *pkey = NULL;
size_t pklen, sklen;
int ret = -1;
if ((ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_ED25519, NULL)) == NULL) {
debug3_f("EVP_PKEY_CTX_new_id failed");
goto out;
}
if (EVP_PKEY_keygen_init(ctx) <= 0) {
debug3_f("EVP_PKEY_keygen_init failed");
goto out;
}
if (EVP_PKEY_keygen(ctx, &pkey) <= 0) {
debug3_f("EVP_PKEY_keygen failed");
goto out;
}
/* Extract public key */
pklen = crypto_sign_ed25519_PUBLICKEYBYTES;
if (!EVP_PKEY_get_raw_public_key(pkey, pk, &pklen)) {
debug3_f("EVP_PKEY_get_raw_public_key failed");
goto out;
}
if (pklen != crypto_sign_ed25519_PUBLICKEYBYTES) {
debug3_f("public key length mismatch: %zu", pklen);
goto out;
}
sklen = SSH_ED25519_RAW_SECRET_KEY_LEN;
/* Extract private key (32 bytes seed) */
if (!EVP_PKEY_get_raw_private_key(pkey, sk, &sklen)) {
debug3_f("EVP_PKEY_get_raw_private_key failed");
goto out;
}
if (sklen != SSH_ED25519_RAW_SECRET_KEY_LEN) {
debug3_f("private key length mismatch: %zu", sklen);
goto out;
}
/* Append public key to secret key (SUPERCOP format compatibility) */
memcpy(sk + sklen, pk, crypto_sign_ed25519_PUBLICKEYBYTES);
ret = 0;
out:
EVP_PKEY_free(pkey);
EVP_PKEY_CTX_free(ctx);
return ret;
}
int
crypto_sign_ed25519_keypair_from_seed(unsigned char *pk, unsigned char *sk,
const unsigned char *seed)
{
EVP_PKEY *pkey = NULL;
size_t pklen;
int ret = -1;
if ((pkey = EVP_PKEY_new_raw_private_key(EVP_PKEY_ED25519, NULL,
seed, SSH_ED25519_RAW_SECRET_KEY_LEN)) == NULL) {
debug3_f("EVP_PKEY_new_raw_private_key failed");
goto out;
}
/* Extract public key */
pklen = crypto_sign_ed25519_PUBLICKEYBYTES;
if (!EVP_PKEY_get_raw_public_key(pkey, pk, &pklen)) {
debug3_f("EVP_PKEY_get_raw_public_key failed");
goto out;
}
/* Build sk = seed || pk */
memcpy(sk, seed, SSH_ED25519_RAW_SECRET_KEY_LEN);
memcpy(sk + SSH_ED25519_RAW_SECRET_KEY_LEN, pk,
crypto_sign_ed25519_PUBLICKEYBYTES);
ret = 0;
out:
EVP_PKEY_free(pkey);
return ret;
}
int
crypto_sign_ed25519(unsigned char *sm, unsigned long long *smlen,
const unsigned char *m, unsigned long long mlen,
const unsigned char *sk)
{
EVP_PKEY *pkey = NULL;
EVP_MD_CTX *mdctx = NULL;
size_t siglen;
int ret = -1;
/* Create EVP_PKEY from secret key (first 32 bytes are the seed) */
if ((pkey = EVP_PKEY_new_raw_private_key(EVP_PKEY_ED25519, NULL,
sk, SSH_ED25519_RAW_SECRET_KEY_LEN)) == NULL) {
debug3_f("EVP_PKEY_new_raw_private_key failed");
goto out;
}
/* Sign the message */
if ((mdctx = EVP_MD_CTX_new()) == NULL) {
debug3_f("EVP_MD_CTX_new failed");
goto out;
}
if (EVP_DigestSignInit(mdctx, NULL, NULL, NULL, pkey) != 1) {
debug3_f("EVP_DigestSignInit failed");
goto out;
}
siglen = crypto_sign_ed25519_BYTES;
if (EVP_DigestSign(mdctx, sm, &siglen, m, mlen) != 1) {
debug3_f("EVP_DigestSign failed");
goto out;
}
if (siglen != crypto_sign_ed25519_BYTES) {
debug3_f("signature length mismatch: %zu", siglen);
goto out;
}
/* Append message after signature (SUPERCOP format) */
if (mlen > ULLONG_MAX - siglen) {
debug3_f("message length overflow: siglen=%zu mlen=%llu",
siglen, mlen);
goto out;
}
memmove(sm + siglen, m, mlen);
*smlen = siglen + mlen;
ret = 0;
out:
EVP_MD_CTX_free(mdctx);
EVP_PKEY_free(pkey);
return ret;
}
int
crypto_sign_ed25519_open(unsigned char *m, unsigned long long *mlen,
const unsigned char *sm, unsigned long long smlen,
const unsigned char *pk)
{
EVP_PKEY *pkey = NULL;
EVP_MD_CTX *mdctx = NULL;
int ret = -1;
const unsigned char *msg;
size_t msglen;
if (smlen < crypto_sign_ed25519_BYTES) {
debug3_f("signed message bad length: %llu", smlen);
return -1;
}
if (smlen - crypto_sign_ed25519_BYTES > SIZE_MAX) {
debug3_f("signed message too long: %llu", smlen);
return -1;
}
/* Signature is first crypto_sign_ed25519_BYTES, message follows */
msg = sm + crypto_sign_ed25519_BYTES;
msglen = smlen - crypto_sign_ed25519_BYTES;
/* Make sure the message buffer is big enough. */
if (*mlen < msglen) {
debug_f("message bad length: %llu", *mlen);
return -1;
}
/* Create EVP_PKEY from public key */
if ((pkey = EVP_PKEY_new_raw_public_key(EVP_PKEY_ED25519, NULL,
pk, crypto_sign_ed25519_PUBLICKEYBYTES)) == NULL) {
debug3_f("EVP_PKEY_new_raw_public_key failed");
goto out;
}
if ((mdctx = EVP_MD_CTX_new()) == NULL) {
debug3_f("EVP_MD_CTX_new failed");
goto out;
}
if (EVP_DigestVerifyInit(mdctx, NULL, NULL, NULL, pkey) <= 0) {
debug3_f("EVP_DigestVerifyInit failed");
goto out;
}
if (EVP_DigestVerify(mdctx, sm, crypto_sign_ed25519_BYTES,
msg, msglen) != 1) {
debug3_f("EVP_DigestVerify failed");
goto out;
}
/* Copy message out */
*mlen = msglen;
memmove(m, msg, msglen);
ret = 0;
out:
EVP_MD_CTX_free(mdctx);
EVP_PKEY_free(pkey);
return ret;
}
#endif /* OPENSSL_HAS_ED25519 */
|
