kexecdh.c revision 262566 
1/* $OpenBSD: kexecdh.c,v 1.5 2014/01/09 23:20:00 djm Exp $ */
2/*
3 * Copyright (c) 2001 Markus Friedl.  All rights reserved.
4 * Copyright (c) 2010 Damien Miller.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include "includes.h"
28
29#ifdef OPENSSL_HAS_ECC
30
31#include <sys/types.h>
32
33#include <signal.h>
34#include <string.h>
35
36#include <openssl/bn.h>
37#include <openssl/evp.h>
38#include <openssl/ec.h>
39#include <openssl/ecdh.h>
40
41#include "buffer.h"
42#include "ssh2.h"
43#include "key.h"
44#include "cipher.h"
45#include "kex.h"
46#include "log.h"
47#include "digest.h"
48
49void
50kex_ecdh_hash(
51    int hash_alg,
52    const EC_GROUP *ec_group,
53    char *client_version_string,
54    char *server_version_string,
55    char *ckexinit, int ckexinitlen,
56    char *skexinit, int skexinitlen,
57    u_char *serverhostkeyblob, int sbloblen,
58    const EC_POINT *client_dh_pub,
59    const EC_POINT *server_dh_pub,
60    const BIGNUM *shared_secret,
61    u_char **hash, u_int *hashlen)
62{
63	Buffer b;
64	static u_char digest[SSH_DIGEST_MAX_LENGTH];
65
66	buffer_init(&b);
67	buffer_put_cstring(&b, client_version_string);
68	buffer_put_cstring(&b, server_version_string);
69
70	/* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
71	buffer_put_int(&b, ckexinitlen+1);
72	buffer_put_char(&b, SSH2_MSG_KEXINIT);
73	buffer_append(&b, ckexinit, ckexinitlen);
74	buffer_put_int(&b, skexinitlen+1);
75	buffer_put_char(&b, SSH2_MSG_KEXINIT);
76	buffer_append(&b, skexinit, skexinitlen);
77
78	buffer_put_string(&b, serverhostkeyblob, sbloblen);
79	buffer_put_ecpoint(&b, ec_group, client_dh_pub);
80	buffer_put_ecpoint(&b, ec_group, server_dh_pub);
81	buffer_put_bignum2(&b, shared_secret);
82
83#ifdef DEBUG_KEX
84	buffer_dump(&b);
85#endif
86	if (ssh_digest_buffer(hash_alg, &b, digest, sizeof(digest)) != 0)
87		fatal("%s: ssh_digest_buffer failed", __func__);
88
89	buffer_free(&b);
90
91#ifdef DEBUG_KEX
92	dump_digest("hash", digest, ssh_digest_bytes(hash_alg));
93#endif
94	*hash = digest;
95	*hashlen = ssh_digest_bytes(hash_alg);
96}
97#endif /* OPENSSL_HAS_ECC */
98