1 /*
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"
27 RCSID("$OpenBSD: kexgex.c,v 1.22 2002/03/24 17:27:03 stevesk Exp $");
28
29 #pragma ident "%Z%%M% %I% %E% SMI"
30
31 #include <openssl/bn.h>
32
33 #include "xmalloc.h"
34 #include "buffer.h"
35 #include "bufaux.h"
36 #include "key.h"
37 #include "kex.h"
38 #include "log.h"
39 #include "packet.h"
40 #include "dh.h"
41 #include "ssh2.h"
42 #include "compat.h"
43
44 u_char *
kexgex_hash(char * client_version_string,char * server_version_string,char * ckexinit,int ckexinitlen,char * skexinit,int skexinitlen,u_char * serverhostkeyblob,int sbloblen,int min,int wantbits,int max,BIGNUM * prime,BIGNUM * gen,BIGNUM * client_dh_pub,BIGNUM * server_dh_pub,BIGNUM * shared_secret)45 kexgex_hash(
46 char *client_version_string,
47 char *server_version_string,
48 char *ckexinit, int ckexinitlen,
49 char *skexinit, int skexinitlen,
50 u_char *serverhostkeyblob, int sbloblen,
51 int min, int wantbits, int max, BIGNUM *prime, BIGNUM *gen,
52 BIGNUM *client_dh_pub,
53 BIGNUM *server_dh_pub,
54 BIGNUM *shared_secret)
55 {
56 Buffer b;
57 static u_char digest[EVP_MAX_MD_SIZE];
58 const EVP_MD *evp_md = EVP_sha1();
59 EVP_MD_CTX md;
60
61 buffer_init(&b);
62 buffer_put_cstring(&b, client_version_string);
63 buffer_put_cstring(&b, server_version_string);
64
65 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
66 buffer_put_int(&b, ckexinitlen+1);
67 buffer_put_char(&b, SSH2_MSG_KEXINIT);
68 buffer_append(&b, ckexinit, ckexinitlen);
69 buffer_put_int(&b, skexinitlen+1);
70 buffer_put_char(&b, SSH2_MSG_KEXINIT);
71 buffer_append(&b, skexinit, skexinitlen);
72
73 buffer_put_string(&b, serverhostkeyblob, sbloblen);
74 if (min == -1 || max == -1)
75 buffer_put_int(&b, wantbits);
76 else {
77 buffer_put_int(&b, min);
78 buffer_put_int(&b, wantbits);
79 buffer_put_int(&b, max);
80 }
81 buffer_put_bignum2(&b, prime);
82 buffer_put_bignum2(&b, gen);
83 buffer_put_bignum2(&b, client_dh_pub);
84 buffer_put_bignum2(&b, server_dh_pub);
85 buffer_put_bignum2(&b, shared_secret);
86
87 #ifdef DEBUG_KEXDH
88 buffer_dump(&b);
89 #endif
90 EVP_DigestInit(&md, evp_md);
91 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
92 EVP_DigestFinal(&md, digest, NULL);
93
94 buffer_free(&b);
95
96 #ifdef DEBUG_KEXDH
97 dump_digest("hash", digest, EVP_MD_size(evp_md));
98 #endif
99 return digest;
100 }
101