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
|
/* crypto/ecdh/ech_ossl.c */
/* ====================================================================
* Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
*
* The Elliptic Curve Public-Key Crypto Library (ECC Code) included
* herein is developed by SUN MICROSYSTEMS, INC., and is contributed
* to the OpenSSL project.
*
* The ECC Code is licensed pursuant to the OpenSSL open source
* license provided below.
*
* The ECDH software is originally written by Douglas Stebila of
* Sun Microsystems Laboratories.
*
*/
/* ====================================================================
* Copyright (c) 1998-2003 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
*
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* openssl-core@OpenSSL.org.
*
* 5. Products derived from this software may not be called "OpenSSL"
* nor may "OpenSSL" appear in their names without prior written
* permission of the OpenSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*
* This product includes cryptographic software written by Eric Young
* (eay@cryptsoft.com). This product includes software written by Tim
* Hudson (tjh@cryptsoft.com).
*
*/
#include <string.h>
#include <limits.h>
#include "cryptlib.h"
#include "ech_locl.h"
#include <openssl/err.h>
#include <openssl/sha.h>
#include <openssl/obj_mac.h>
#include <openssl/bn.h>
static int ecdh_compute_key(void *out, size_t len, const EC_POINT *pub_key,
EC_KEY *ecdh,
void *(*KDF) (const void *in, size_t inlen,
void *out, size_t *outlen));
static ECDH_METHOD openssl_ecdh_meth = {
"OpenSSL ECDH method",
ecdh_compute_key,
#if 0
NULL, /* init */
NULL, /* finish */
#endif
0, /* flags */
NULL /* app_data */
};
const ECDH_METHOD *ECDH_OpenSSL(void)
{
return &openssl_ecdh_meth;
}
/*-
* This implementation is based on the following primitives in the IEEE 1363 standard:
* - ECKAS-DH1
* - ECSVDP-DH
* Finally an optional KDF is applied.
*/
static int ecdh_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
EC_KEY *ecdh,
void *(*KDF) (const void *in, size_t inlen,
void *out, size_t *outlen))
{
BN_CTX *ctx;
EC_POINT *tmp = NULL;
BIGNUM *x = NULL, *y = NULL;
const BIGNUM *priv_key;
const EC_GROUP *group;
int ret = -1;
size_t buflen, len;
unsigned char *buf = NULL;
if (outlen > INT_MAX) {
ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ERR_R_MALLOC_FAILURE); /* sort of,
* anyway */
return -1;
}
if ((ctx = BN_CTX_new()) == NULL)
goto err;
BN_CTX_start(ctx);
x = BN_CTX_get(ctx);
y = BN_CTX_get(ctx);
priv_key = EC_KEY_get0_private_key(ecdh);
if (priv_key == NULL) {
ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ECDH_R_NO_PRIVATE_VALUE);
goto err;
}
group = EC_KEY_get0_group(ecdh);
if ((tmp = EC_POINT_new(group)) == NULL) {
ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!EC_POINT_mul(group, tmp, NULL, pub_key, priv_key, ctx)) {
ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ECDH_R_POINT_ARITHMETIC_FAILURE);
goto err;
}
if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) ==
NID_X9_62_prime_field) {
if (!EC_POINT_get_affine_coordinates_GFp(group, tmp, x, y, ctx)) {
ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ECDH_R_POINT_ARITHMETIC_FAILURE);
goto err;
}
}
#ifndef OPENSSL_NO_EC2M
else {
if (!EC_POINT_get_affine_coordinates_GF2m(group, tmp, x, y, ctx)) {
ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ECDH_R_POINT_ARITHMETIC_FAILURE);
goto err;
}
}
#endif
buflen = (EC_GROUP_get_degree(group) + 7) / 8;
len = BN_num_bytes(x);
if (len > buflen) {
ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ERR_R_INTERNAL_ERROR);
goto err;
}
if ((buf = OPENSSL_malloc(buflen)) == NULL) {
ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ERR_R_MALLOC_FAILURE);
goto err;
}
memset(buf, 0, buflen - len);
if (len != (size_t)BN_bn2bin(x, buf + buflen - len)) {
ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ERR_R_BN_LIB);
goto err;
}
if (KDF != 0) {
if (KDF(buf, buflen, out, &outlen) == NULL) {
ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ECDH_R_KDF_FAILED);
goto err;
}
ret = outlen;
} else {
/* no KDF, just copy as much as we can */
if (outlen > buflen)
outlen = buflen;
memcpy(out, buf, outlen);
ret = outlen;
}
err:
if (tmp)
EC_POINT_free(tmp);
if (ctx)
BN_CTX_end(ctx);
if (ctx)
BN_CTX_free(ctx);
if (buf)
OPENSSL_free(buf);
return (ret);
}
|
