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Ben Lindstrom22b19b42001-04-04 17:39:19 +00001/*
2 * Copyright (c) 2000 Niels Provos. All rights reserved.
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"
Damien Miller8e7fb332003-02-24 12:03:03 +110027RCSID("$OpenBSD: kexgex.c,v 1.23 2003/02/16 17:09:57 markus Exp $");
Ben Lindstrom22b19b42001-04-04 17:39:19 +000028
Damien Miller8e7fb332003-02-24 12:03:03 +110029#include <openssl/evp.h>
Ben Lindstrom22b19b42001-04-04 17:39:19 +000030
Ben Lindstrom22b19b42001-04-04 17:39:19 +000031#include "buffer.h"
32#include "bufaux.h"
Ben Lindstrom22b19b42001-04-04 17:39:19 +000033#include "kex.h"
Ben Lindstrom22b19b42001-04-04 17:39:19 +000034#include "ssh2.h"
Ben Lindstrom22b19b42001-04-04 17:39:19 +000035
Damien Miller8e7fb332003-02-24 12:03:03 +110036u_char *
Ben Lindstrom22b19b42001-04-04 17:39:19 +000037kexgex_hash(
38 char *client_version_string,
39 char *server_version_string,
40 char *ckexinit, int ckexinitlen,
41 char *skexinit, int skexinitlen,
Ben Lindstrom9e0ddd42001-09-18 05:41:19 +000042 u_char *serverhostkeyblob, int sbloblen,
Ben Lindstrom22b19b42001-04-04 17:39:19 +000043 int min, int wantbits, int max, BIGNUM *prime, BIGNUM *gen,
44 BIGNUM *client_dh_pub,
45 BIGNUM *server_dh_pub,
46 BIGNUM *shared_secret)
47{
48 Buffer b;
49 static u_char digest[EVP_MAX_MD_SIZE];
Ben Lindstrom80cb27d2002-03-05 01:33:36 +000050 const EVP_MD *evp_md = EVP_sha1();
Ben Lindstrom22b19b42001-04-04 17:39:19 +000051 EVP_MD_CTX md;
52
53 buffer_init(&b);
Ben Lindstrom664408d2001-06-09 01:42:01 +000054 buffer_put_cstring(&b, client_version_string);
55 buffer_put_cstring(&b, server_version_string);
Ben Lindstrom22b19b42001-04-04 17:39:19 +000056
57 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
58 buffer_put_int(&b, ckexinitlen+1);
59 buffer_put_char(&b, SSH2_MSG_KEXINIT);
60 buffer_append(&b, ckexinit, ckexinitlen);
61 buffer_put_int(&b, skexinitlen+1);
62 buffer_put_char(&b, SSH2_MSG_KEXINIT);
63 buffer_append(&b, skexinit, skexinitlen);
64
65 buffer_put_string(&b, serverhostkeyblob, sbloblen);
Ben Lindstroma3700052001-04-05 23:26:32 +000066 if (min == -1 || max == -1)
Ben Lindstrom22b19b42001-04-04 17:39:19 +000067 buffer_put_int(&b, wantbits);
68 else {
69 buffer_put_int(&b, min);
70 buffer_put_int(&b, wantbits);
71 buffer_put_int(&b, max);
72 }
73 buffer_put_bignum2(&b, prime);
74 buffer_put_bignum2(&b, gen);
75 buffer_put_bignum2(&b, client_dh_pub);
76 buffer_put_bignum2(&b, server_dh_pub);
77 buffer_put_bignum2(&b, shared_secret);
78
79#ifdef DEBUG_KEXDH
80 buffer_dump(&b);
81#endif
82 EVP_DigestInit(&md, evp_md);
83 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
84 EVP_DigestFinal(&md, digest, NULL);
85
86 buffer_free(&b);
87
88#ifdef DEBUG_KEXDH
Damien Miller3672e4b2002-02-05 11:54:07 +110089 dump_digest("hash", digest, EVP_MD_size(evp_md));
Ben Lindstrom22b19b42001-04-04 17:39:19 +000090#endif
91 return digest;
92}