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Damien Miller57c30112006-03-26 14:24:48 +11001/* $OpenBSD: kexgex.c,v 1.26 2006/03/25 13:17:02 djm Exp $ */
Ben Lindstrom22b19b42001-04-04 17:39:19 +00002/*
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"
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 Miller19bb3a52005-11-05 15:19:35 +110036void
Ben Lindstrom22b19b42001-04-04 17:39:19 +000037kexgex_hash(
Damien Miller19bb3a52005-11-05 15:19:35 +110038 const EVP_MD *evp_md,
Ben Lindstrom22b19b42001-04-04 17:39:19 +000039 char *client_version_string,
40 char *server_version_string,
41 char *ckexinit, int ckexinitlen,
42 char *skexinit, int skexinitlen,
Ben Lindstrom9e0ddd42001-09-18 05:41:19 +000043 u_char *serverhostkeyblob, int sbloblen,
Ben Lindstrom22b19b42001-04-04 17:39:19 +000044 int min, int wantbits, int max, BIGNUM *prime, BIGNUM *gen,
45 BIGNUM *client_dh_pub,
46 BIGNUM *server_dh_pub,
Damien Miller19bb3a52005-11-05 15:19:35 +110047 BIGNUM *shared_secret,
48 u_char **hash, u_int *hashlen)
Ben Lindstrom22b19b42001-04-04 17:39:19 +000049{
50 Buffer b;
51 static u_char digest[EVP_MAX_MD_SIZE];
Ben Lindstrom22b19b42001-04-04 17:39:19 +000052 EVP_MD_CTX md;
53
54 buffer_init(&b);
Ben Lindstrom664408d2001-06-09 01:42:01 +000055 buffer_put_cstring(&b, client_version_string);
56 buffer_put_cstring(&b, server_version_string);
Ben Lindstrom22b19b42001-04-04 17:39:19 +000057
58 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
59 buffer_put_int(&b, ckexinitlen+1);
60 buffer_put_char(&b, SSH2_MSG_KEXINIT);
61 buffer_append(&b, ckexinit, ckexinitlen);
62 buffer_put_int(&b, skexinitlen+1);
63 buffer_put_char(&b, SSH2_MSG_KEXINIT);
64 buffer_append(&b, skexinit, skexinitlen);
65
66 buffer_put_string(&b, serverhostkeyblob, sbloblen);
Ben Lindstroma3700052001-04-05 23:26:32 +000067 if (min == -1 || max == -1)
Ben Lindstrom22b19b42001-04-04 17:39:19 +000068 buffer_put_int(&b, wantbits);
69 else {
70 buffer_put_int(&b, min);
71 buffer_put_int(&b, wantbits);
72 buffer_put_int(&b, max);
73 }
74 buffer_put_bignum2(&b, prime);
75 buffer_put_bignum2(&b, gen);
76 buffer_put_bignum2(&b, client_dh_pub);
77 buffer_put_bignum2(&b, server_dh_pub);
78 buffer_put_bignum2(&b, shared_secret);
79
80#ifdef DEBUG_KEXDH
81 buffer_dump(&b);
82#endif
Damien Miller19bb3a52005-11-05 15:19:35 +110083
Ben Lindstrom22b19b42001-04-04 17:39:19 +000084 EVP_DigestInit(&md, evp_md);
85 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
86 EVP_DigestFinal(&md, digest, NULL);
87
88 buffer_free(&b);
Damien Miller19bb3a52005-11-05 15:19:35 +110089 *hash = digest;
90 *hashlen = EVP_MD_size(evp_md);
Ben Lindstrom22b19b42001-04-04 17:39:19 +000091#ifdef DEBUG_KEXDH
Damien Miller19bb3a52005-11-05 15:19:35 +110092 dump_digest("hash", digest, *hashlen);
Ben Lindstrom22b19b42001-04-04 17:39:19 +000093#endif
Ben Lindstrom22b19b42001-04-04 17:39:19 +000094}