[openssh.git] / kexdh.c

/*
 * 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"
RCSID("$OpenBSD: kexdh.c,v 1.18 2002/03/18 17:50:31 provos Exp $");

#include <openssl/crypto.h>
#include <openssl/bn.h>

#include "xmalloc.h"
#include "buffer.h"
#include "bufaux.h"
#include "key.h"
#include "kex.h"
#include "log.h"
#include "packet.h"
#include "dh.h"
#include "ssh2.h"
#include "monitor_wrap.h"

static u_char *
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)
{
	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
	return digest;
}

/* client */

static void
kexdh_client(Kex *kex)
{
	BIGNUM *dh_server_pub = NULL, *shared_secret = NULL;
	DH *dh;
	Key *server_host_key;
	u_char *server_host_key_blob = NULL, *signature = NULL;
	u_char *kbuf, *hash;
	u_int klen, kout, slen, sbloblen;

	/* generate and send 'e', client DH public key */
	dh = dh_new_group1();
	dh_gen_key(dh, kex->we_need * 8);
	packet_start(SSH2_MSG_KEXDH_INIT);
	packet_put_bignum2(dh->pub_key);
	packet_send();

	debug("sending SSH2_MSG_KEXDH_INIT");
#ifdef DEBUG_KEXDH
	DHparams_print_fp(stderr, dh);
	fprintf(stderr, "pub= ");
	BN_print_fp(stderr, dh->pub_key);
	fprintf(stderr, "\n");
#endif

	debug("expecting SSH2_MSG_KEXDH_REPLY");
	packet_read_expect(SSH2_MSG_KEXDH_REPLY);

	/* key, cert */
	server_host_key_blob = packet_get_string(&sbloblen);
	server_host_key = key_from_blob(server_host_key_blob, sbloblen);
	if (server_host_key == NULL)
		fatal("cannot decode server_host_key_blob");
	if (server_host_key->type != kex->hostkey_type)
		fatal("type mismatch for decoded server_host_key_blob");
	if (kex->verify_host_key == NULL)
		fatal("cannot verify server_host_key");
	if (kex->verify_host_key(server_host_key) == -1)
		fatal("server_host_key verification failed");

	/* DH paramter f, server public DH key */
	if ((dh_server_pub = BN_new()) == NULL)
		fatal("dh_server_pub == NULL");
	packet_get_bignum2(dh_server_pub);

#ifdef DEBUG_KEXDH
	fprintf(stderr, "dh_server_pub= ");
	BN_print_fp(stderr, dh_server_pub);
	fprintf(stderr, "\n");
	debug("bits %d", BN_num_bits(dh_server_pub));
#endif

	/* signed H */
	signature = packet_get_string(&slen);
	packet_check_eom();

	if (!dh_pub_is_valid(dh, dh_server_pub))
		packet_disconnect("bad server public DH value");

	klen = DH_size(dh);
	kbuf = xmalloc(klen);
	kout = DH_compute_key(kbuf, dh_server_pub, dh);
#ifdef DEBUG_KEXDH
	dump_digest("shared secret", kbuf, kout);
#endif
	if ((shared_secret = BN_new()) == NULL)
		fatal("kexdh_client: BN_new failed");
	BN_bin2bn(kbuf, kout, shared_secret);
	memset(kbuf, 0, klen);
	xfree(kbuf);

	/* calc and verify H */
	hash = kex_dh_hash(
	    kex->client_version_string,
	    kex->server_version_string,
	    buffer_ptr(&kex->my), buffer_len(&kex->my),
	    buffer_ptr(&kex->peer), buffer_len(&kex->peer),
	    server_host_key_blob, sbloblen,
	    dh->pub_key,
	    dh_server_pub,
	    shared_secret
	);
	xfree(server_host_key_blob);
	BN_clear_free(dh_server_pub);
	DH_free(dh);

	if (key_verify(server_host_key, signature, slen, hash, 20) != 1)
		fatal("key_verify failed for server_host_key");
	key_free(server_host_key);
	xfree(signature);

	/* save session id */
	if (kex->session_id == NULL) {
		kex->session_id_len = 20;
		kex->session_id = xmalloc(kex->session_id_len);
		memcpy(kex->session_id, hash, kex->session_id_len);
	}

	kex_derive_keys(kex, hash, shared_secret);
	BN_clear_free(shared_secret);
	kex_finish(kex);
}

/* server */

static void
kexdh_server(Kex *kex)
{
	BIGNUM *shared_secret = NULL, *dh_client_pub = NULL;
	DH *dh;
	Key *server_host_key;
	u_char *kbuf, *hash, *signature = NULL, *server_host_key_blob = NULL;
	u_int sbloblen, klen, kout;
	u_int slen;

	/* generate server DH public key */
	dh = dh_new_group1();
	dh_gen_key(dh, kex->we_need * 8);

	debug("expecting SSH2_MSG_KEXDH_INIT");
	packet_read_expect(SSH2_MSG_KEXDH_INIT);

	if (kex->load_host_key == NULL)
		fatal("Cannot load hostkey");
	server_host_key = kex->load_host_key(kex->hostkey_type);
	if (server_host_key == NULL)
		fatal("Unsupported hostkey type %d", kex->hostkey_type);

	/* key, cert */
	if ((dh_client_pub = BN_new()) == NULL)
		fatal("dh_client_pub == NULL");
	packet_get_bignum2(dh_client_pub);
	packet_check_eom();

#ifdef DEBUG_KEXDH
	fprintf(stderr, "dh_client_pub= ");
	BN_print_fp(stderr, dh_client_pub);
	fprintf(stderr, "\n");
	debug("bits %d", BN_num_bits(dh_client_pub));
#endif

#ifdef DEBUG_KEXDH
	DHparams_print_fp(stderr, dh);
	fprintf(stderr, "pub= ");
	BN_print_fp(stderr, dh->pub_key);
	fprintf(stderr, "\n");
#endif
	if (!dh_pub_is_valid(dh, dh_client_pub))
		packet_disconnect("bad client public DH value");

	klen = DH_size(dh);
	kbuf = xmalloc(klen);
	kout = DH_compute_key(kbuf, dh_client_pub, dh);
#ifdef DEBUG_KEXDH
	dump_digest("shared secret", kbuf, kout);
#endif
	if ((shared_secret = BN_new()) == NULL)
		fatal("kexdh_server: BN_new failed");
	BN_bin2bn(kbuf, kout, shared_secret);
	memset(kbuf, 0, klen);
	xfree(kbuf);

	key_to_blob(server_host_key, &server_host_key_blob, &sbloblen);

	/* calc H */
	hash = kex_dh_hash(
	    kex->client_version_string,
	    kex->server_version_string,
	    buffer_ptr(&kex->peer), buffer_len(&kex->peer),
	    buffer_ptr(&kex->my), buffer_len(&kex->my),
	    server_host_key_blob, sbloblen,
	    dh_client_pub,
	    dh->pub_key,
	    shared_secret
	);
	BN_clear_free(dh_client_pub);

	/* save session id := H */
	/* XXX hashlen depends on KEX */
	if (kex->session_id == NULL) {
		kex->session_id_len = 20;
		kex->session_id = xmalloc(kex->session_id_len);
		memcpy(kex->session_id, hash, kex->session_id_len);
	}

	/* sign H */
	/* XXX hashlen depends on KEX */
	PRIVSEP(key_sign(server_host_key, &signature, &slen, hash, 20));

	/* destroy_sensitive_data(); */

	/* send server hostkey, DH pubkey 'f' and singed H */
	packet_start(SSH2_MSG_KEXDH_REPLY);
	packet_put_string(server_host_key_blob, sbloblen);
	packet_put_bignum2(dh->pub_key);	/* f */
	packet_put_string(signature, slen);
	packet_send();

	xfree(signature);
	xfree(server_host_key_blob);
	/* have keys, free DH */
	DH_free(dh);

	kex_derive_keys(kex, hash, shared_secret);
	BN_clear_free(shared_secret);
	kex_finish(kex);
}

void
kexdh(Kex *kex)
{
	if (kex->server)
		kexdh_server(kex);
	else
		kexdh_client(kex);
}
Commit	Line	Data
0bc35151	1	/*
	2	* Copyright (c) 2001 Markus Friedl. All rights reserved.
	3	*
	4	* Redistribution and use in source and binary forms, with or without
	5	* modification, are permitted provided that the following conditions
	6	* are met:
	7	* 1. Redistributions of source code must retain the above copyright
	8	* notice, this list of conditions and the following disclaimer.
	9	* 2. Redistributions in binary form must reproduce the above copyright
	10	* notice, this list of conditions and the following disclaimer in the
	11	* documentation and/or other materials provided with the distribution.
	12	*
	13	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	14	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	15	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	16	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	17	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	18	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	19	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	20	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	21	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	22	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	23	*/
	24
	25	#include "includes.h"
1853d1ef	26	RCSID("$OpenBSD: kexdh.c,v 1.18 2002/03/18 17:50:31 provos Exp $");
0bc35151	27
	28	#include <openssl/crypto.h>
	29	#include <openssl/bn.h>
	30
	31	#include "xmalloc.h"
	32	#include "buffer.h"
	33	#include "bufaux.h"
	34	#include "key.h"
	35	#include "kex.h"
	36	#include "log.h"
	37	#include "packet.h"
	38	#include "dh.h"
	39	#include "ssh2.h"
1853d1ef	40	#include "monitor_wrap.h"
0bc35151	41
396c147e	42	static u_char *
0bc35151	43	kex_dh_hash(
	44	char *client_version_string,
	45	char *server_version_string,
	46	char *ckexinit, int ckexinitlen,
	47	char *skexinit, int skexinitlen,
cf54363d	48	u_char *serverhostkeyblob, int sbloblen,
0bc35151	49	BIGNUM *client_dh_pub,
	50	BIGNUM *server_dh_pub,
	51	BIGNUM *shared_secret)
	52	{
	53	Buffer b;
	54	static u_char digest[EVP_MAX_MD_SIZE];
714954dc	55	const EVP_MD *evp_md = EVP_sha1();
0bc35151	56	EVP_MD_CTX md;
	57
	58	buffer_init(&b);
449c5ba5	59	buffer_put_cstring(&b, client_version_string);
449c5ba5	60	buffer_put_cstring(&b, server_version_string);
0bc35151	61
	62	/* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
	63	buffer_put_int(&b, ckexinitlen+1);
	64	buffer_put_char(&b, SSH2_MSG_KEXINIT);
	65	buffer_append(&b, ckexinit, ckexinitlen);
	66	buffer_put_int(&b, skexinitlen+1);
	67	buffer_put_char(&b, SSH2_MSG_KEXINIT);
	68	buffer_append(&b, skexinit, skexinitlen);
	69
	70	buffer_put_string(&b, serverhostkeyblob, sbloblen);
	71	buffer_put_bignum2(&b, client_dh_pub);
	72	buffer_put_bignum2(&b, server_dh_pub);
	73	buffer_put_bignum2(&b, shared_secret);
	74
	75	#ifdef DEBUG_KEX
	76	buffer_dump(&b);
	77	#endif
	78	EVP_DigestInit(&md, evp_md);
	79	EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
	80	EVP_DigestFinal(&md, digest, NULL);
	81
	82	buffer_free(&b);
	83
	84	#ifdef DEBUG_KEX
a209a158	85	dump_digest("hash", digest, EVP_MD_size(evp_md));
0bc35151	86	#endif
	87	return digest;
	88	}
	89
	90	/* client */
	91
396c147e	92	static void
0bc35151	93	kexdh_client(Kex *kex)
	94	{
	95	BIGNUM dh_server_pub = NULL, shared_secret = NULL;
	96	DH *dh;
	97	Key *server_host_key;
cf54363d	98	u_char server_host_key_blob = NULL, signature = NULL;
0bc35151	99	u_char kbuf, hash;
0bc35151	100	u_int klen, kout, slen, sbloblen;
0bc35151	101
	102	/* generate and send 'e', client DH public key */
	103	dh = dh_new_group1();
	104	dh_gen_key(dh, kex->we_need * 8);
	105	packet_start(SSH2_MSG_KEXDH_INIT);
	106	packet_put_bignum2(dh->pub_key);
	107	packet_send();
	108
	109	debug("sending SSH2_MSG_KEXDH_INIT");
	110	#ifdef DEBUG_KEXDH
	111	DHparams_print_fp(stderr, dh);
	112	fprintf(stderr, "pub= ");
	113	BN_print_fp(stderr, dh->pub_key);
	114	fprintf(stderr, "\n");
	115	#endif
	116
	117	debug("expecting SSH2_MSG_KEXDH_REPLY");
54a5250f	118	packet_read_expect(SSH2_MSG_KEXDH_REPLY);
0bc35151	119
	120	/* key, cert */
	121	server_host_key_blob = packet_get_string(&sbloblen);
	122	server_host_key = key_from_blob(server_host_key_blob, sbloblen);
	123	if (server_host_key == NULL)
	124	fatal("cannot decode server_host_key_blob");
215ced77	125	if (server_host_key->type != kex->hostkey_type)
215ced77	126	fatal("type mismatch for decoded server_host_key_blob");
f49bc4f7	127	if (kex->verify_host_key == NULL)
	128	fatal("cannot verify server_host_key");
	129	if (kex->verify_host_key(server_host_key) == -1)
	130	fatal("server_host_key verification failed");
0bc35151	131
0bc35151	132	/* DH paramter f, server public DH key */
b775c6f2	133	if ((dh_server_pub = BN_new()) == NULL)
0bc35151	134	fatal("dh_server_pub == NULL");
20b279e6	135	packet_get_bignum2(dh_server_pub);
0bc35151	136
	137	#ifdef DEBUG_KEXDH
	138	fprintf(stderr, "dh_server_pub= ");
	139	BN_print_fp(stderr, dh_server_pub);
	140	fprintf(stderr, "\n");
	141	debug("bits %d", BN_num_bits(dh_server_pub));
	142	#endif
	143
	144	/* signed H */
	145	signature = packet_get_string(&slen);
95500969	146	packet_check_eom();
0bc35151	147
	148	if (!dh_pub_is_valid(dh, dh_server_pub))
	149	packet_disconnect("bad server public DH value");
	150
	151	klen = DH_size(dh);
	152	kbuf = xmalloc(klen);
	153	kout = DH_compute_key(kbuf, dh_server_pub, dh);
	154	#ifdef DEBUG_KEXDH
	155	dump_digest("shared secret", kbuf, kout);
	156	#endif
b775c6f2	157	if ((shared_secret = BN_new()) == NULL)
b775c6f2	158	fatal("kexdh_client: BN_new failed");
0bc35151	159	BN_bin2bn(kbuf, kout, shared_secret);
	160	memset(kbuf, 0, klen);
	161	xfree(kbuf);
	162
	163	/* calc and verify H */
	164	hash = kex_dh_hash(
	165	kex->client_version_string,
	166	kex->server_version_string,
	167	buffer_ptr(&kex->my), buffer_len(&kex->my),
	168	buffer_ptr(&kex->peer), buffer_len(&kex->peer),
	169	server_host_key_blob, sbloblen,
	170	dh->pub_key,
	171	dh_server_pub,
	172	shared_secret
	173	);
	174	xfree(server_host_key_blob);
108d362e	175	BN_clear_free(dh_server_pub);
d8ee838b	176	DH_free(dh);
0bc35151	177
cf54363d	178	if (key_verify(server_host_key, signature, slen, hash, 20) != 1)
0bc35151	179	fatal("key_verify failed for server_host_key");
	180	key_free(server_host_key);
	181	xfree(signature);
	182
	183	/* save session id */
	184	if (kex->session_id == NULL) {
	185	kex->session_id_len = 20;
	186	kex->session_id = xmalloc(kex->session_id_len);
	187	memcpy(kex->session_id, hash, kex->session_id_len);
	188	}
	189
	190	kex_derive_keys(kex, hash, shared_secret);
	191	BN_clear_free(shared_secret);
d8ee838b	192	kex_finish(kex);
0bc35151	193	}
	194
	195	/* server */
	196
396c147e	197	static void
0bc35151	198	kexdh_server(Kex *kex)
	199	{
	200	BIGNUM shared_secret = NULL, dh_client_pub = NULL;
	201	DH *dh;
	202	Key *server_host_key;
	203	u_char kbuf, hash, signature = NULL, server_host_key_blob = NULL;
	204	u_int sbloblen, klen, kout;
c66f9d0e	205	u_int slen;
0bc35151	206
	207	/* generate server DH public key */
	208	dh = dh_new_group1();
	209	dh_gen_key(dh, kex->we_need * 8);
	210
	211	debug("expecting SSH2_MSG_KEXDH_INIT");
54a5250f	212	packet_read_expect(SSH2_MSG_KEXDH_INIT);
0bc35151	213
	214	if (kex->load_host_key == NULL)
	215	fatal("Cannot load hostkey");
	216	server_host_key = kex->load_host_key(kex->hostkey_type);
	217	if (server_host_key == NULL)
	218	fatal("Unsupported hostkey type %d", kex->hostkey_type);
	219
	220	/* key, cert */
b775c6f2	221	if ((dh_client_pub = BN_new()) == NULL)
0bc35151	222	fatal("dh_client_pub == NULL");
20b279e6	223	packet_get_bignum2(dh_client_pub);
b967d870	224	packet_check_eom();
0bc35151	225
	226	#ifdef DEBUG_KEXDH
	227	fprintf(stderr, "dh_client_pub= ");
	228	BN_print_fp(stderr, dh_client_pub);
	229	fprintf(stderr, "\n");
	230	debug("bits %d", BN_num_bits(dh_client_pub));
	231	#endif
	232
	233	#ifdef DEBUG_KEXDH
	234	DHparams_print_fp(stderr, dh);
	235	fprintf(stderr, "pub= ");
	236	BN_print_fp(stderr, dh->pub_key);
	237	fprintf(stderr, "\n");
	238	#endif
	239	if (!dh_pub_is_valid(dh, dh_client_pub))
	240	packet_disconnect("bad client public DH value");
	241
	242	klen = DH_size(dh);
	243	kbuf = xmalloc(klen);
	244	kout = DH_compute_key(kbuf, dh_client_pub, dh);
	245	#ifdef DEBUG_KEXDH
	246	dump_digest("shared secret", kbuf, kout);
	247	#endif
b775c6f2	248	if ((shared_secret = BN_new()) == NULL)
b775c6f2	249	fatal("kexdh_server: BN_new failed");
0bc35151	250	BN_bin2bn(kbuf, kout, shared_secret);
	251	memset(kbuf, 0, klen);
	252	xfree(kbuf);
	253
	254	key_to_blob(server_host_key, &server_host_key_blob, &sbloblen);
	255
	256	/* calc H */
	257	hash = kex_dh_hash(
	258	kex->client_version_string,
	259	kex->server_version_string,
	260	buffer_ptr(&kex->peer), buffer_len(&kex->peer),
	261	buffer_ptr(&kex->my), buffer_len(&kex->my),
cf54363d	262	server_host_key_blob, sbloblen,
0bc35151	263	dh_client_pub,
	264	dh->pub_key,
	265	shared_secret
	266	);
108d362e	267	BN_clear_free(dh_client_pub);
0bc35151	268
	269	/* save session id := H */
	270	/* XXX hashlen depends on KEX */
	271	if (kex->session_id == NULL) {
	272	kex->session_id_len = 20;
	273	kex->session_id = xmalloc(kex->session_id_len);
	274	memcpy(kex->session_id, hash, kex->session_id_len);
	275	}
	276
	277	/* sign H */
	278	/* XXX hashlen depends on KEX */
1853d1ef	279	PRIVSEP(key_sign(server_host_key, &signature, &slen, hash, 20));
0bc35151	280
	281	/* destroy_sensitive_data(); */
	282
	283	/* send server hostkey, DH pubkey 'f' and singed H */
	284	packet_start(SSH2_MSG_KEXDH_REPLY);
cf54363d	285	packet_put_string(server_host_key_blob, sbloblen);
0bc35151	286	packet_put_bignum2(dh->pub_key); /* f */
cf54363d	287	packet_put_string(signature, slen);
0bc35151	288	packet_send();
d8ee838b	289
0bc35151	290	xfree(signature);
0bc35151	291	xfree(server_host_key_blob);
d8ee838b	292	/* have keys, free DH */
d8ee838b	293	DH_free(dh);
0bc35151	294
	295	kex_derive_keys(kex, hash, shared_secret);
	296	BN_clear_free(shared_secret);
d8ee838b	297	kex_finish(kex);
0bc35151	298	}
	299
	300	void
	301	kexdh(Kex *kex)
	302	{
	303	if (kex->server)
	304	kexdh_server(kex);
	305	else
	306	kexdh_client(kex);
	307	}