1 /* $OpenBSD: kexdh.c,v 1.26 2016/05/02 10:26:04 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 #ifdef WITH_OPENSSL
29
30 #include <sys/types.h>
31
32 #include <signal.h>
33
34 #include <openssl/evp.h>
35
36 #include "ssh2.h"
37 #include "sshkey.h"
38 #include "cipher.h"
39 #include "kex.h"
40 #include "ssherr.h"
41 #include "sshbuf.h"
42 #include "digest.h"
43
44 int
kex_dh_hash(int hash_alg,const char * client_version_string,const char * server_version_string,const u_char * ckexinit,size_t ckexinitlen,const u_char * skexinit,size_t skexinitlen,const u_char * serverhostkeyblob,size_t sbloblen,const BIGNUM * client_dh_pub,const BIGNUM * server_dh_pub,const BIGNUM * shared_secret,u_char * hash,size_t * hashlen)45 kex_dh_hash(
46 int hash_alg,
47 const char *client_version_string,
48 const char *server_version_string,
49 const u_char *ckexinit, size_t ckexinitlen,
50 const u_char *skexinit, size_t skexinitlen,
51 const u_char *serverhostkeyblob, size_t sbloblen,
52 const BIGNUM *client_dh_pub,
53 const BIGNUM *server_dh_pub,
54 const BIGNUM *shared_secret,
55 u_char *hash, size_t *hashlen)
56 {
57 struct sshbuf *b;
58 int r;
59
60 if (*hashlen < ssh_digest_bytes(hash_alg))
61 return SSH_ERR_INVALID_ARGUMENT;
62 if ((b = sshbuf_new()) == NULL)
63 return SSH_ERR_ALLOC_FAIL;
64 if ((r = sshbuf_put_cstring(b, client_version_string)) != 0 ||
65 (r = sshbuf_put_cstring(b, server_version_string)) != 0 ||
66 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
67 (r = sshbuf_put_u32(b, ckexinitlen+1)) != 0 ||
68 (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
69 (r = sshbuf_put(b, ckexinit, ckexinitlen)) != 0 ||
70 (r = sshbuf_put_u32(b, skexinitlen+1)) != 0 ||
71 (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
72 (r = sshbuf_put(b, skexinit, skexinitlen)) != 0 ||
73 (r = sshbuf_put_string(b, serverhostkeyblob, sbloblen)) != 0 ||
74 (r = sshbuf_put_bignum2(b, client_dh_pub)) != 0 ||
75 (r = sshbuf_put_bignum2(b, server_dh_pub)) != 0 ||
76 (r = sshbuf_put_bignum2(b, shared_secret)) != 0) {
77 sshbuf_free(b);
78 return r;
79 }
80 #ifdef DEBUG_KEX
81 sshbuf_dump(b, stderr);
82 #endif
83 if (ssh_digest_buffer(hash_alg, b, hash, *hashlen) != 0) {
84 sshbuf_free(b);
85 return SSH_ERR_LIBCRYPTO_ERROR;
86 }
87 sshbuf_free(b);
88 *hashlen = ssh_digest_bytes(hash_alg);
89 #ifdef DEBUG_KEX
90 dump_digest("hash", hash, *hashlen);
91 #endif
92 return 0;
93 }
94 #endif /* WITH_OPENSSL */
95