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Ben Lindstrom22b19b42001-04-04 17:39:19 +00001/*
2 * Copyright (c) 2001 Markus Friedl. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25#include "includes.h"
Damien Miller8e7fb332003-02-24 12:03:03 +110026RCSID("$OpenBSD: kexdh.c,v 1.19 2003/02/16 17:09:57 markus Exp $");
Ben Lindstrom22b19b42001-04-04 17:39:19 +000027
Damien Miller8e7fb332003-02-24 12:03:03 +110028#include <openssl/evp.h>
Ben Lindstrom22b19b42001-04-04 17:39:19 +000029
Ben Lindstrom22b19b42001-04-04 17:39:19 +000030#include "buffer.h"
31#include "bufaux.h"
Ben Lindstrom22b19b42001-04-04 17:39:19 +000032#include "ssh2.h"
Damien Miller8e7fb332003-02-24 12:03:03 +110033#include "kex.h"
Ben Lindstrom22b19b42001-04-04 17:39:19 +000034
Damien Miller8e7fb332003-02-24 12:03:03 +110035u_char *
Ben Lindstrom22b19b42001-04-04 17:39:19 +000036kex_dh_hash(
37 char *client_version_string,
38 char *server_version_string,
39 char *ckexinit, int ckexinitlen,
40 char *skexinit, int skexinitlen,
Ben Lindstrom9e0ddd42001-09-18 05:41:19 +000041 u_char *serverhostkeyblob, int sbloblen,
Ben Lindstrom22b19b42001-04-04 17:39:19 +000042 BIGNUM *client_dh_pub,
43 BIGNUM *server_dh_pub,
44 BIGNUM *shared_secret)
45{
46 Buffer b;
47 static u_char digest[EVP_MAX_MD_SIZE];
Ben Lindstrom80cb27d2002-03-05 01:33:36 +000048 const EVP_MD *evp_md = EVP_sha1();
Ben Lindstrom22b19b42001-04-04 17:39:19 +000049 EVP_MD_CTX md;
50
51 buffer_init(&b);
Ben Lindstrom664408d2001-06-09 01:42:01 +000052 buffer_put_cstring(&b, client_version_string);
53 buffer_put_cstring(&b, server_version_string);
Ben Lindstrom22b19b42001-04-04 17:39:19 +000054
55 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
56 buffer_put_int(&b, ckexinitlen+1);
57 buffer_put_char(&b, SSH2_MSG_KEXINIT);
58 buffer_append(&b, ckexinit, ckexinitlen);
59 buffer_put_int(&b, skexinitlen+1);
60 buffer_put_char(&b, SSH2_MSG_KEXINIT);
61 buffer_append(&b, skexinit, skexinitlen);
62
63 buffer_put_string(&b, serverhostkeyblob, sbloblen);
64 buffer_put_bignum2(&b, client_dh_pub);
65 buffer_put_bignum2(&b, server_dh_pub);
66 buffer_put_bignum2(&b, shared_secret);
67
68#ifdef DEBUG_KEX
69 buffer_dump(&b);
70#endif
71 EVP_DigestInit(&md, evp_md);
72 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
73 EVP_DigestFinal(&md, digest, NULL);
74
75 buffer_free(&b);
76
77#ifdef DEBUG_KEX
Damien Miller3672e4b2002-02-05 11:54:07 +110078 dump_digest("hash", digest, EVP_MD_size(evp_md));
Ben Lindstrom22b19b42001-04-04 17:39:19 +000079#endif
80 return digest;
81}