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djm@openbsd.org0a843d92018-12-27 03:25:24 +00001/* $OpenBSD: kexecdh.c,v 1.7 2018/12/27 03:25:25 djm Exp $ */
Damien Millereb8b60e2010-08-31 22:41:14 +10002/*
3 * Copyright (c) 2001 Markus Friedl. All rights reserved.
4 * Copyright (c) 2010 Damien Miller. 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
Damien Millerc79ff072010-08-31 22:50:48 +100027#include "includes.h"
28
Damien Miller72ef7c12015-01-15 02:21:31 +110029#if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC)
Damien Miller6af914a2010-09-10 11:39:26 +100030
Damien Millereb8b60e2010-08-31 22:41:14 +100031#include <sys/types.h>
32
33#include <signal.h>
34#include <string.h>
35
36#include <openssl/bn.h>
37#include <openssl/evp.h>
38#include <openssl/ec.h>
39#include <openssl/ecdh.h>
40
Damien Millereb8b60e2010-08-31 22:41:14 +100041#include "ssh2.h"
markus@openbsd.org57d10cb2015-01-19 20:16:15 +000042#include "sshkey.h"
Damien Millereb8b60e2010-08-31 22:41:14 +100043#include "cipher.h"
44#include "kex.h"
markus@openbsd.org57d10cb2015-01-19 20:16:15 +000045#include "sshbuf.h"
Damien Millerb3051d02014-01-10 10:58:53 +110046#include "digest.h"
markus@openbsd.org57d10cb2015-01-19 20:16:15 +000047#include "ssherr.h"
Damien Millereb8b60e2010-08-31 22:41:14 +100048
markus@openbsd.org57d10cb2015-01-19 20:16:15 +000049int
Damien Millereb8b60e2010-08-31 22:41:14 +100050kex_ecdh_hash(
Damien Millerb3051d02014-01-10 10:58:53 +110051 int hash_alg,
Damien Millereb8b60e2010-08-31 22:41:14 +100052 const EC_GROUP *ec_group,
djm@openbsd.org0a843d92018-12-27 03:25:24 +000053 const struct sshbuf *client_version,
54 const struct sshbuf *server_version,
markus@openbsd.org57d10cb2015-01-19 20:16:15 +000055 const u_char *ckexinit, size_t ckexinitlen,
56 const u_char *skexinit, size_t skexinitlen,
57 const u_char *serverhostkeyblob, size_t sbloblen,
Damien Millereb8b60e2010-08-31 22:41:14 +100058 const EC_POINT *client_dh_pub,
59 const EC_POINT *server_dh_pub,
60 const BIGNUM *shared_secret,
markus@openbsd.org57d10cb2015-01-19 20:16:15 +000061 u_char *hash, size_t *hashlen)
Damien Millereb8b60e2010-08-31 22:41:14 +100062{
markus@openbsd.org57d10cb2015-01-19 20:16:15 +000063 struct sshbuf *b;
64 int r;
Damien Millereb8b60e2010-08-31 22:41:14 +100065
markus@openbsd.org57d10cb2015-01-19 20:16:15 +000066 if (*hashlen < ssh_digest_bytes(hash_alg))
67 return SSH_ERR_INVALID_ARGUMENT;
68 if ((b = sshbuf_new()) == NULL)
69 return SSH_ERR_ALLOC_FAIL;
djm@openbsd.org0a843d92018-12-27 03:25:24 +000070 if ((r = sshbuf_put_stringb(b, client_version)) < 0 ||
71 (r = sshbuf_put_stringb(b, server_version)) < 0 ||
markus@openbsd.org57d10cb2015-01-19 20:16:15 +000072 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
73 (r = sshbuf_put_u32(b, ckexinitlen+1)) != 0 ||
74 (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
75 (r = sshbuf_put(b, ckexinit, ckexinitlen)) != 0 ||
76 (r = sshbuf_put_u32(b, skexinitlen+1)) != 0 ||
77 (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
78 (r = sshbuf_put(b, skexinit, skexinitlen)) != 0 ||
79 (r = sshbuf_put_string(b, serverhostkeyblob, sbloblen)) != 0 ||
80 (r = sshbuf_put_ec(b, client_dh_pub, ec_group)) != 0 ||
81 (r = sshbuf_put_ec(b, server_dh_pub, ec_group)) != 0 ||
82 (r = sshbuf_put_bignum2(b, shared_secret)) != 0) {
83 sshbuf_free(b);
84 return r;
85 }
Damien Millereb8b60e2010-08-31 22:41:14 +100086#ifdef DEBUG_KEX
markus@openbsd.org57d10cb2015-01-19 20:16:15 +000087 sshbuf_dump(b, stderr);
Damien Millereb8b60e2010-08-31 22:41:14 +100088#endif
markus@openbsd.org57d10cb2015-01-19 20:16:15 +000089 if (ssh_digest_buffer(hash_alg, b, hash, *hashlen) != 0) {
90 sshbuf_free(b);
91 return SSH_ERR_LIBCRYPTO_ERROR;
92 }
93 sshbuf_free(b);
Damien Millerb3051d02014-01-10 10:58:53 +110094 *hashlen = ssh_digest_bytes(hash_alg);
markus@openbsd.org57d10cb2015-01-19 20:16:15 +000095#ifdef DEBUG_KEX
96 dump_digest("hash", hash, *hashlen);
97#endif
98 return 0;
Damien Millereb8b60e2010-08-31 22:41:14 +100099}
Damien Miller72ef7c12015-01-15 02:21:31 +1100100#endif /* defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) */