summaryrefslogtreecommitdiffstats
path: root/ssh-ed25519.c
blob: 7dee82707ffbc6184e4295a90f82984853a52d27 (plain)
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
/* $OpenBSD: ssh-ed25519.c,v 1.8 2020/02/26 13:40:09 jsg 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"
#include "ssh.h"

int
ssh_ed25519_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
    const u_char *data, size_t datalen, u_int compat)
{
	u_char *sig = NULL;
	size_t slen = 0, len;
	unsigned long long smlen;
	int r, ret;
	struct sshbuf *b = NULL;

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

	if (key == NULL ||
	    sshkey_type_plain(key->type) != KEY_ED25519 ||
	    key->ed25519_sk == NULL ||
	    datalen >= INT_MAX - crypto_sign_ed25519_BYTES)
		return SSH_ERR_INVALID_ARGUMENT;
	smlen = slen = datalen + crypto_sign_ed25519_BYTES;
	if ((sig = malloc(slen)) == NULL)
		return SSH_ERR_ALLOC_FAIL;

	if ((ret = crypto_sign_ed25519(sig, &smlen, data, datalen,
	    key->ed25519_sk)) != 0 || smlen <= datalen) {
		r = SSH_ERR_INVALID_ARGUMENT; /* XXX better error? */
		goto out;
	}
	/* 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, smlen - datalen)) != 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);
	if (sig != NULL) 
		freezero(sig, slen);

	return r;
}

int
ssh_ed25519_verify(const struct sshkey *key,
    const u_char *signature, size_t signaturelen,
    const u_char *data, size_t datalen, u_int compat)
{
	struct sshbuf *b = NULL;
	char *ktype = NULL;
	const u_char *sigblob;
	u_char *sm = NULL, *m = NULL;
	size_t len;
	unsigned long long smlen = 0, mlen = 0;
	int r, ret;

	if (key == NULL ||
	    sshkey_type_plain(key->type) != KEY_ED25519 ||
	    key->ed25519_pk == NULL ||
	    datalen >= INT_MAX - crypto_sign_ed25519_BYTES ||
	    signature == NULL || signaturelen == 0)
		return SSH_ERR_INVALID_ARGUMENT;

	if ((b = sshbuf_from(signature, signaturelen)) == 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 (datalen >= SIZE_MAX - len) {
		r = SSH_ERR_INVALID_ARGUMENT;
		goto out;
	}
	smlen = len + datalen;
	mlen = smlen;
	if ((sm = malloc(smlen)) == NULL || (m = malloc(mlen)) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	memcpy(sm, sigblob, len);
	memcpy(sm+len, data, datalen);
	if ((ret = crypto_sign_ed25519_open(m, &mlen, sm, smlen,
	    key->ed25519_pk)) != 0) {
		debug2("%s: crypto_sign_ed25519_open failed: %d",
		    __func__, ret);
	}
	if (ret != 0 || mlen != datalen) {
		r = SSH_ERR_SIGNATURE_INVALID;
		goto out;
	}
	/* XXX compare 'm' and 'data' ? */
	/* success */
	r = 0;
 out:
	if (sm != NULL) 
		freezero(sm, smlen);
	if (m != NULL) 
		freezero(m, smlen); /* NB mlen may be invalid if r != 0 */
	sshbuf_free(b);
	free(ktype);
	return r;
}