1 /* $OpenBSD: kexgex.c,v 1.32 2019/01/23 00:30:41 djm Exp $ */
2 /*
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"
28
29 #ifdef WITH_OPENSSL
30
31 #include <sys/types.h>
32
33 #include <openssl/evp.h>
34 #include <signal.h>
35
36 #include "openbsd-compat/openssl-compat.h"
37
38 #include "sshkey.h"
39 #include "cipher.h"
40 #include "kex.h"
41 #include "ssh2.h"
42 #include "ssherr.h"
43 #include "sshbuf.h"
44 #include "digest.h"
45
46 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)47 kexgex_hash(
48 int hash_alg,
49 const struct sshbuf *client_version,
50 const struct sshbuf *server_version,
51 const struct sshbuf *client_kexinit,
52 const struct sshbuf *server_kexinit,
53 const struct sshbuf *server_host_key_blob,
54 int min, int wantbits, int max,
55 const BIGNUM *prime,
56 const BIGNUM *gen,
57 const BIGNUM *client_dh_pub,
58 const BIGNUM *server_dh_pub,
59 const u_char *shared_secret, size_t secretlen,
60 u_char *hash, size_t *hashlen)
61 {
62 struct sshbuf *b;
63 int r;
64
65 if (*hashlen < ssh_digest_bytes(SSH_DIGEST_SHA1))
66 return SSH_ERR_INVALID_ARGUMENT;
67 if ((b = sshbuf_new()) == NULL)
68 return SSH_ERR_ALLOC_FAIL;
69 if ((r = sshbuf_put_stringb(b, client_version)) < 0 ||
70 (r = sshbuf_put_stringb(b, server_version)) < 0 ||
71 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
72 (r = sshbuf_put_u32(b, sshbuf_len(client_kexinit) + 1)) != 0 ||
73 (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
74 (r = sshbuf_putb(b, client_kexinit)) != 0 ||
75 (r = sshbuf_put_u32(b, sshbuf_len(server_kexinit) + 1)) != 0 ||
76 (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
77 (r = sshbuf_putb(b, server_kexinit)) != 0 ||
78 (r = sshbuf_put_stringb(b, server_host_key_blob)) != 0 ||
79 (min != -1 && (r = sshbuf_put_u32(b, min)) != 0) ||
80 (r = sshbuf_put_u32(b, wantbits)) != 0 ||
81 (max != -1 && (r = sshbuf_put_u32(b, max)) != 0) ||
82 (r = sshbuf_put_bignum2(b, prime)) != 0 ||
83 (r = sshbuf_put_bignum2(b, gen)) != 0 ||
84 (r = sshbuf_put_bignum2(b, client_dh_pub)) != 0 ||
85 (r = sshbuf_put_bignum2(b, server_dh_pub)) != 0 ||
86 (r = sshbuf_put(b, shared_secret, secretlen)) != 0) {
87 sshbuf_free(b);
88 return r;
89 }
90 #ifdef DEBUG_KEXDH
91 sshbuf_dump(b, stderr);
92 #endif
93 if (ssh_digest_buffer(hash_alg, b, hash, *hashlen) != 0) {
94 sshbuf_free(b);
95 return SSH_ERR_LIBCRYPTO_ERROR;
96 }
97 sshbuf_free(b);
98 *hashlen = ssh_digest_bytes(hash_alg);
99 #ifdef DEBUG_KEXDH
100 dump_digest("hash", hash, *hashlen);
101 #endif
102 return 0;
103 }
104 #endif /* WITH_OPENSSL */
105