[openssh.git] / kexdh.c

/* $OpenBSD: kexdh.c,v 1.22 2006/03/25 13:17:02 djm Exp $ */
/*
 * Copyright (c) 2001 Markus Friedl.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "includes.h"

#include <openssl/evp.h>

#include "buffer.h"
#include "bufaux.h"
#include "ssh2.h"
#include "kex.h"

void
kex_dh_hash(
    char *client_version_string,
    char *server_version_string,
    char *ckexinit, int ckexinitlen,
    char *skexinit, int skexinitlen,
    u_char *serverhostkeyblob, int sbloblen,
    BIGNUM *client_dh_pub,
    BIGNUM *server_dh_pub,
    BIGNUM *shared_secret,
    u_char **hash, u_int *hashlen)
{
	Buffer b;
	static u_char digest[EVP_MAX_MD_SIZE];
	const EVP_MD *evp_md = EVP_sha1();
	EVP_MD_CTX md;

	buffer_init(&b);
	buffer_put_cstring(&b, client_version_string);
	buffer_put_cstring(&b, server_version_string);

	/* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
	buffer_put_int(&b, ckexinitlen+1);
	buffer_put_char(&b, SSH2_MSG_KEXINIT);
	buffer_append(&b, ckexinit, ckexinitlen);
	buffer_put_int(&b, skexinitlen+1);
	buffer_put_char(&b, SSH2_MSG_KEXINIT);
	buffer_append(&b, skexinit, skexinitlen);

	buffer_put_string(&b, serverhostkeyblob, sbloblen);
	buffer_put_bignum2(&b, client_dh_pub);
	buffer_put_bignum2(&b, server_dh_pub);
	buffer_put_bignum2(&b, shared_secret);

#ifdef DEBUG_KEX
	buffer_dump(&b);
#endif
	EVP_DigestInit(&md, evp_md);
	EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
	EVP_DigestFinal(&md, digest, NULL);

	buffer_free(&b);

#ifdef DEBUG_KEX
	dump_digest("hash", digest, EVP_MD_size(evp_md));
#endif
	*hash = digest;
	*hashlen = EVP_MD_size(evp_md);
}
Commit	Line	Data
c1cb7bae	1	/* $OpenBSD: kexdh.c,v 1.22 2006/03/25 13:17:02 djm Exp $ */
0bc35151	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"
0bc35151	27
98a58eda	28	#include <openssl/evp.h>
0bc35151	29
0bc35151	30	#include "buffer.h"
0bc35151	31	#include "bufaux.h"
0bc35151	32	#include "ssh2.h"
98a58eda	33	#include "kex.h"
0bc35151	34
47e5dc72	35	void
0bc35151	36	kex_dh_hash(
	37	char *client_version_string,
	38	char *server_version_string,
	39	char *ckexinit, int ckexinitlen,
	40	char *skexinit, int skexinitlen,
cf54363d	41	u_char *serverhostkeyblob, int sbloblen,
0bc35151	42	BIGNUM *client_dh_pub,
0bc35151	43	BIGNUM *server_dh_pub,
47e5dc72	44	BIGNUM *shared_secret,
47e5dc72	45	u_char *hash, u_int hashlen)
0bc35151	46	{
	47	Buffer b;
	48	static u_char digest[EVP_MAX_MD_SIZE];
714954dc	49	const EVP_MD *evp_md = EVP_sha1();
0bc35151	50	EVP_MD_CTX md;
	51
	52	buffer_init(&b);
449c5ba5	53	buffer_put_cstring(&b, client_version_string);
449c5ba5	54	buffer_put_cstring(&b, server_version_string);
0bc35151	55
	56	/* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
	57	buffer_put_int(&b, ckexinitlen+1);
	58	buffer_put_char(&b, SSH2_MSG_KEXINIT);
	59	buffer_append(&b, ckexinit, ckexinitlen);
	60	buffer_put_int(&b, skexinitlen+1);
	61	buffer_put_char(&b, SSH2_MSG_KEXINIT);
	62	buffer_append(&b, skexinit, skexinitlen);
	63
	64	buffer_put_string(&b, serverhostkeyblob, sbloblen);
	65	buffer_put_bignum2(&b, client_dh_pub);
	66	buffer_put_bignum2(&b, server_dh_pub);
	67	buffer_put_bignum2(&b, shared_secret);
	68
	69	#ifdef DEBUG_KEX
	70	buffer_dump(&b);
	71	#endif
	72	EVP_DigestInit(&md, evp_md);
	73	EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
	74	EVP_DigestFinal(&md, digest, NULL);
	75
	76	buffer_free(&b);
	77
	78	#ifdef DEBUG_KEX
a209a158	79	dump_digest("hash", digest, EVP_MD_size(evp_md));
0bc35151	80	#endif
47e5dc72	81	*hash = digest;
47e5dc72	82	*hashlen = EVP_MD_size(evp_md);
0bc35151	83	}