1 /* $NetBSD: kexgex.c,v 1.7 2019/04/20 17:16:40 christos Exp $ */
2 /* $OpenBSD: kexgex.c,v 1.32 2019/01/23 00:30:41 djm Exp $ */
3 /*
4 * Copyright (c) 2000 Niels Provos. All rights reserved.
5 * Copyright (c) 2001 Markus Friedl. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include "includes.h"
29 __RCSID("$NetBSD: kexgex.c,v 1.7 2019/04/20 17:16:40 christos Exp $");
30 #include <sys/types.h>
31
32 #include <openssl/evp.h>
33 #include <signal.h>
34
35 #include "sshkey.h"
36 #include "cipher.h"
37 #include "kex.h"
38 #include "ssh2.h"
39 #include "ssherr.h"
40 #include "sshbuf.h"
41 #include "digest.h"
42
43 int
kexgex_hash(int hash_alg,const struct sshbuf * client_version,const struct sshbuf * server_version,const struct sshbuf * client_kexinit,const struct sshbuf * server_kexinit,const struct sshbuf * server_host_key_blob,int min,int wantbits,int max,const BIGNUM * prime,const BIGNUM * gen,const BIGNUM * client_dh_pub,const BIGNUM * server_dh_pub,const u_char * shared_secret,size_t secretlen,u_char * hash,size_t * hashlen)44 kexgex_hash(
45 int hash_alg,
46 const struct sshbuf *client_version,
47 const struct sshbuf *server_version,
48 const struct sshbuf *client_kexinit,
49 const struct sshbuf *server_kexinit,
50 const struct sshbuf *server_host_key_blob,
51 int min, int wantbits, int max,
52 const BIGNUM *prime,
53 const BIGNUM *gen,
54 const BIGNUM *client_dh_pub,
55 const BIGNUM *server_dh_pub,
56 const u_char *shared_secret, size_t secretlen,
57 u_char *hash, size_t *hashlen)
58 {
59 struct sshbuf *b;
60 int r;
61
62 if (*hashlen < ssh_digest_bytes(SSH_DIGEST_SHA1))
63 return SSH_ERR_INVALID_ARGUMENT;
64 if ((b = sshbuf_new()) == NULL)
65 return SSH_ERR_ALLOC_FAIL;
66 if ((r = sshbuf_put_stringb(b, client_version)) < 0 ||
67 (r = sshbuf_put_stringb(b, server_version)) < 0 ||
68 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
69 (r = sshbuf_put_u32(b, sshbuf_len(client_kexinit) + 1)) != 0 ||
70 (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
71 (r = sshbuf_putb(b, client_kexinit)) != 0 ||
72 (r = sshbuf_put_u32(b, sshbuf_len(server_kexinit) + 1)) != 0 ||
73 (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
74 (r = sshbuf_putb(b, server_kexinit)) != 0 ||
75 (r = sshbuf_put_stringb(b, server_host_key_blob)) != 0 ||
76 (min != -1 && (r = sshbuf_put_u32(b, min)) != 0) ||
77 (r = sshbuf_put_u32(b, wantbits)) != 0 ||
78 (max != -1 && (r = sshbuf_put_u32(b, max)) != 0) ||
79 (r = sshbuf_put_bignum2(b, prime)) != 0 ||
80 (r = sshbuf_put_bignum2(b, gen)) != 0 ||
81 (r = sshbuf_put_bignum2(b, client_dh_pub)) != 0 ||
82 (r = sshbuf_put_bignum2(b, server_dh_pub)) != 0 ||
83 (r = sshbuf_put(b, shared_secret, secretlen)) != 0) {
84 sshbuf_free(b);
85 return r;
86 }
87 #ifdef DEBUG_KEXDH
88 sshbuf_dump(b, stderr);
89 #endif
90 if (ssh_digest_buffer(hash_alg, b, hash, *hashlen) != 0) {
91 sshbuf_free(b);
92 return SSH_ERR_LIBCRYPTO_ERROR;
93 }
94 sshbuf_free(b);
95 *hashlen = ssh_digest_bytes(hash_alg);
96 #ifdef DEBUG_KEXDH
97 dump_digest("hash", hash, *hashlen);
98 #endif
99 return 0;
100 }
101