kexgex.c revision 262566 
1/* $OpenBSD: kexgex.c,v 1.28 2014/01/09 23:20:00 djm Exp $ */
2/*
3 * Copyright (c) 2000 Niels Provos.  All rights reserved.
4 * Copyright (c) 2001 Markus Friedl.  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#include <sys/types.h>
30
31#include <openssl/evp.h>
32#include <signal.h>
33
34#include "buffer.h"
35#include "key.h"
36#include "cipher.h"
37#include "kex.h"
38#include "ssh2.h"
39#include "digest.h"
40#include "log.h"
41
42void
43kexgex_hash(
44    int hash_alg,
45    char *client_version_string,
46    char *server_version_string,
47    char *ckexinit, int ckexinitlen,
48    char *skexinit, int skexinitlen,
49    u_char *serverhostkeyblob, int sbloblen,
50    int min, int wantbits, int max, BIGNUM *prime, BIGNUM *gen,
51    BIGNUM *client_dh_pub,
52    BIGNUM *server_dh_pub,
53    BIGNUM *shared_secret,
54    u_char **hash, u_int *hashlen)
55{
56	Buffer b;
57	static u_char digest[SSH_DIGEST_MAX_LENGTH];
58
59	buffer_init(&b);
60	buffer_put_cstring(&b, client_version_string);
61	buffer_put_cstring(&b, server_version_string);
62
63	/* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
64	buffer_put_int(&b, ckexinitlen+1);
65	buffer_put_char(&b, SSH2_MSG_KEXINIT);
66	buffer_append(&b, ckexinit, ckexinitlen);
67	buffer_put_int(&b, skexinitlen+1);
68	buffer_put_char(&b, SSH2_MSG_KEXINIT);
69	buffer_append(&b, skexinit, skexinitlen);
70
71	buffer_put_string(&b, serverhostkeyblob, sbloblen);
72	if (min == -1 || max == -1)
73		buffer_put_int(&b, wantbits);
74	else {
75		buffer_put_int(&b, min);
76		buffer_put_int(&b, wantbits);
77		buffer_put_int(&b, max);
78	}
79	buffer_put_bignum2(&b, prime);
80	buffer_put_bignum2(&b, gen);
81	buffer_put_bignum2(&b, client_dh_pub);
82	buffer_put_bignum2(&b, server_dh_pub);
83	buffer_put_bignum2(&b, shared_secret);
84
85#ifdef DEBUG_KEXDH
86	buffer_dump(&b);
87#endif
88	if (ssh_digest_buffer(hash_alg, &b, digest, sizeof(digest)) != 0)
89		fatal("%s: ssh_digest_buffer failed", __func__);
90
91	buffer_free(&b);
92
93#ifdef DEBUG_KEX
94	dump_digest("hash", digest, ssh_digest_bytes(hash_alg));
95#endif
96	*hash = digest;
97	*hashlen = ssh_digest_bytes(hash_alg);
98}
99