summaryrefslogtreecommitdiff
path: root/sshbuf-getput-crypto.c
blob: e2e093c002f9e3ead996a29019346c17ca8b46f2 (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
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
/*	$OpenBSD: sshbuf-getput-crypto.c,v 1.4 2015/01/14 15:02:39 djm Exp $	*/
/*
 * Copyright (c) 2011 Damien Miller
 *
 * 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.
 */

#define SSHBUF_INTERNAL
#include "includes.h"

#include <sys/types.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include <openssl/bn.h>
#ifdef OPENSSL_HAS_ECC
# include <openssl/ec.h>
#endif /* OPENSSL_HAS_ECC */

#include "ssherr.h"
#include "sshbuf.h"

int
sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM *v)
{
	const u_char *d;
	size_t len;
	int r;

	if ((r = sshbuf_get_bignum2_bytes_direct(buf, &d, &len)) != 0)
		return r;
	if (v != NULL && BN_bin2bn(d, len, v) == NULL)
		return SSH_ERR_ALLOC_FAIL;
	return 0;
}

int
sshbuf_get_bignum1(struct sshbuf *buf, BIGNUM *v)
{
	const u_char *d = sshbuf_ptr(buf);
	u_int16_t len_bits;
	size_t len_bytes;

	/* Length in bits */
	if (sshbuf_len(buf) < 2)
		return SSH_ERR_MESSAGE_INCOMPLETE;
	len_bits = PEEK_U16(d);
	len_bytes = (len_bits + 7) >> 3;
	if (len_bytes > SSHBUF_MAX_BIGNUM)
		return SSH_ERR_BIGNUM_TOO_LARGE;
	if (sshbuf_len(buf) < 2 + len_bytes)
		return SSH_ERR_MESSAGE_INCOMPLETE;
	if (v != NULL && BN_bin2bn(d + 2, len_bytes, v) == NULL)
		return SSH_ERR_ALLOC_FAIL;
	if (sshbuf_consume(buf, 2 + len_bytes) != 0) {
		SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
		SSHBUF_ABORT();
		return SSH_ERR_INTERNAL_ERROR;
	}
	return 0;
}

#ifdef OPENSSL_HAS_ECC
static int
get_ec(const u_char *d, size_t len, EC_POINT *v, const EC_GROUP *g)
{
	/* Refuse overlong bignums */
	if (len == 0 || len > SSHBUF_MAX_ECPOINT)
		return SSH_ERR_ECPOINT_TOO_LARGE;
	/* Only handle uncompressed points */
	if (*d != POINT_CONVERSION_UNCOMPRESSED)
		return SSH_ERR_INVALID_FORMAT;
	if (v != NULL && EC_POINT_oct2point(g, v, d, len, NULL) != 1)
		return SSH_ERR_INVALID_FORMAT; /* XXX assumption */
	return 0;
}

int
sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g)
{
	const u_char *d;
	size_t len;
	int r;

	if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0)
		return r;
	if ((r = get_ec(d, len, v, g)) != 0)
		return r;
	/* Skip string */
	if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {
		/* Shouldn't happen */
		SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
		SSHBUF_ABORT();
		return SSH_ERR_INTERNAL_ERROR;
	}
	return 0;
}

int
sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v)
{
	EC_POINT *pt = EC_POINT_new(EC_KEY_get0_group(v));
	int r;
	const u_char *d;
	size_t len;

	if (pt == NULL) {
		SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
		return SSH_ERR_ALLOC_FAIL;
	}
	if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0) {
		EC_POINT_free(pt);
		return r;
	}
	if ((r = get_ec(d, len, pt, EC_KEY_get0_group(v))) != 0) {
		EC_POINT_free(pt);
		return r;
	}
	if (EC_KEY_set_public_key(v, pt) != 1) {
		EC_POINT_free(pt);
		return SSH_ERR_ALLOC_FAIL; /* XXX assumption */
	}
	EC_POINT_free(pt);
	/* Skip string */
	if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {
		/* Shouldn't happen */
		SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
		SSHBUF_ABORT();
		return SSH_ERR_INTERNAL_ERROR;
	}
	return 0;	
}
#endif /* OPENSSL_HAS_ECC */

int
sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v)
{
	u_char d[SSHBUF_MAX_BIGNUM + 1];
	int len = BN_num_bytes(v), prepend = 0, r;

	if (len < 0 || len > SSHBUF_MAX_BIGNUM)
		return SSH_ERR_INVALID_ARGUMENT;
	*d = '\0';
	if (BN_bn2bin(v, d + 1) != len)
		return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
	/* If MSB is set, prepend a \0 */
	if (len > 0 && (d[1] & 0x80) != 0)
		prepend = 1;
	if ((r = sshbuf_put_string(buf, d + 1 - prepend, len + prepend)) < 0) {
		bzero(d, sizeof(d));
		return r;
	}
	bzero(d, sizeof(d));
	return 0;
}

int
sshbuf_put_bignum1(struct sshbuf *buf, const BIGNUM *v)
{
	int r, len_bits = BN_num_bits(v);
	size_t len_bytes = (len_bits + 7) / 8;
	u_char d[SSHBUF_MAX_BIGNUM], *dp;

	if (len_bits < 0 || len_bytes > SSHBUF_MAX_BIGNUM)
		return SSH_ERR_INVALID_ARGUMENT;
	if (BN_bn2bin(v, d) != (int)len_bytes)
		return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
	if ((r = sshbuf_reserve(buf, len_bytes + 2, &dp)) < 0) {
		bzero(d, sizeof(d));
		return r;
	}
	POKE_U16(dp, len_bits);
	if (len_bytes != 0)
		memcpy(dp + 2, d, len_bytes);
	bzero(d, sizeof(d));
	return 0;
}

#ifdef OPENSSL_HAS_ECC
int
sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g)
{
	u_char d[SSHBUF_MAX_ECPOINT];
	BN_CTX *bn_ctx;
	size_t len;
	int ret;

	if ((bn_ctx = BN_CTX_new()) == NULL)
		return SSH_ERR_ALLOC_FAIL;
	if ((len = EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED,
	    NULL, 0, bn_ctx)) > SSHBUF_MAX_ECPOINT) {
		BN_CTX_free(bn_ctx);
		return SSH_ERR_INVALID_ARGUMENT;
	}
	if (EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED,
	    d, len, bn_ctx) != len) {
		BN_CTX_free(bn_ctx);
		return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
	}
	BN_CTX_free(bn_ctx);
	ret = sshbuf_put_string(buf, d, len);
	bzero(d, len);
	return ret;
}

int
sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v)
{
	return sshbuf_put_ec(buf, EC_KEY_get0_public_key(v),
	    EC_KEY_get0_group(v));
}
#endif /* OPENSSL_HAS_ECC */