kexdh.c revision 262566 
1/* $OpenBSD: kexdh.c,v 1.24 2014/01/09 23:20:00 djm Exp $ */
2/*
3 * Copyright (c) 2001 Markus Friedl.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "includes.h"
27
28#include <sys/types.h>
29
30#include <signal.h>
31
32#include <openssl/evp.h>
33
34#include "buffer.h"
35#include "ssh2.h"
36#include "key.h"
37#include "cipher.h"
38#include "kex.h"
39#include "digest.h"
40#include "log.h"
41
42void
43kex_dh_hash(
44    char *client_version_string,
45    char *server_version_string,
46    char *ckexinit, int ckexinitlen,
47    char *skexinit, int skexinitlen,
48    u_char *serverhostkeyblob, int sbloblen,
49    BIGNUM *client_dh_pub,
50    BIGNUM *server_dh_pub,
51    BIGNUM *shared_secret,
52    u_char **hash, u_int *hashlen)
53{
54	Buffer b;
55	static u_char digest[SSH_DIGEST_MAX_LENGTH];
56
57	buffer_init(&b);
58	buffer_put_cstring(&b, client_version_string);
59	buffer_put_cstring(&b, server_version_string);
60
61	/* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
62	buffer_put_int(&b, ckexinitlen+1);
63	buffer_put_char(&b, SSH2_MSG_KEXINIT);
64	buffer_append(&b, ckexinit, ckexinitlen);
65	buffer_put_int(&b, skexinitlen+1);
66	buffer_put_char(&b, SSH2_MSG_KEXINIT);
67	buffer_append(&b, skexinit, skexinitlen);
68
69	buffer_put_string(&b, serverhostkeyblob, sbloblen);
70	buffer_put_bignum2(&b, client_dh_pub);
71	buffer_put_bignum2(&b, server_dh_pub);
72	buffer_put_bignum2(&b, shared_secret);
73
74#ifdef DEBUG_KEX
75	buffer_dump(&b);
76#endif
77	if (ssh_digest_buffer(SSH_DIGEST_SHA1, &b, digest, sizeof(digest)) != 0)
78		fatal("%s: ssh_digest_buffer failed", __func__);
79
80	buffer_free(&b);
81
82#ifdef DEBUG_KEX
83	dump_digest("hash", digest, ssh_digest_bytes(SSH_DIGEST_SHA1));
84#endif
85	*hash = digest;
86	*hashlen = ssh_digest_bytes(SSH_DIGEST_SHA1);
87}
88