[gssapi-openssh.git] / openssh / kexgssc.c

/*
 * Copyright (c) 2001-2006 Simon Wilkinson. 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"

#ifdef GSSAPI

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

#include <string.h>

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

#include "ssh-gss.h"

void
kexgss_client(Kex *kex) {
	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	gss_buffer_desc recv_tok, gssbuf, msg_tok, *token_ptr;
	Gssctxt *ctxt;
	OM_uint32 maj_status, min_status, ret_flags;
	u_int klen, kout, slen = 0, hashlen, strlen;
	DH *dh; 
	BIGNUM *dh_server_pub = NULL;
	BIGNUM *shared_secret = NULL;
	BIGNUM *p = NULL;
	BIGNUM *g = NULL;	
	u_char *kbuf, *hash;
	u_char *serverhostkey = NULL;
	char *msg;
	char *lang;
	int type = 0;
	int first = 1;
	int nbits = 0, min = DH_GRP_MIN, max = DH_GRP_MAX;

	/* Initialise our GSSAPI world */	
	ssh_gssapi_build_ctx(&ctxt);
	if (ssh_gssapi_id_kex(ctxt, kex->name, kex->kex_type) 
	    == GSS_C_NO_OID)
		fatal("Couldn't identify host exchange");

	if (ssh_gssapi_import_name(ctxt, kex->gss_host))
		fatal("Couldn't import hostname");
	
	switch (kex->kex_type) {
	case KEX_GSS_GRP1_SHA1:
		dh = dh_new_group1();
		break;
	case KEX_GSS_GRP14_SHA1:
		dh = dh_new_group14();
		break;
	case KEX_GSS_GEX_SHA1:
		debug("Doing group exchange\n");
		nbits = dh_estimate(kex->we_need * 8);
		packet_start(SSH2_MSG_KEXGSS_GROUPREQ);
		packet_put_int(min);
		packet_put_int(nbits);
		packet_put_int(max);

		packet_send();

		packet_read_expect(SSH2_MSG_KEXGSS_GROUP);

		if ((p = BN_new()) == NULL)
			fatal("BN_new() failed");
		packet_get_bignum2(p);
		if ((g = BN_new()) == NULL)
			fatal("BN_new() failed");
		packet_get_bignum2(g);
		packet_check_eom();

		if (BN_num_bits(p) < min || BN_num_bits(p) > max)
			fatal("GSSGRP_GEX group out of range: %d !< %d !< %d",
			    min, BN_num_bits(p), max);

		dh = dh_new_group(g, p);
		break;
	default:
		fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
	}
	
	/* Step 1 - e is dh->pub_key */
	dh_gen_key(dh, kex->we_need * 8);

	/* This is f, we initialise it now to make life easier */
	dh_server_pub = BN_new();
	if (dh_server_pub == NULL)
		fatal("dh_server_pub == NULL");

	token_ptr = GSS_C_NO_BUFFER;
			 
	do {
		debug("Calling gss_init_sec_context");
		
		maj_status = ssh_gssapi_init_ctx(ctxt,
		    kex->gss_deleg_creds, token_ptr, &send_tok,
		    &ret_flags);

		if (GSS_ERROR(maj_status)) {
			if (send_tok.length != 0) {
				packet_start(SSH2_MSG_KEXGSS_CONTINUE);
				packet_put_string(send_tok.value,
				    send_tok.length);
			}
			fatal("gss_init_context failed");
		}

		/* If we've got an old receive buffer get rid of it */
		if (token_ptr != GSS_C_NO_BUFFER)
			xfree(recv_tok.value);

		if (maj_status == GSS_S_COMPLETE) {
			/* If mutual state flag is not true, kex fails */
			if (!(ret_flags & GSS_C_MUTUAL_FLAG))
				fatal("Mutual authentication failed");

			/* If integ avail flag is not true kex fails */
			if (!(ret_flags & GSS_C_INTEG_FLAG))
				fatal("Integrity check failed");
		}

		/* 
		 * If we have data to send, then the last message that we
		 * received cannot have been a 'complete'. 
		 */
		if (send_tok.length != 0) {
			if (first) {
				packet_start(SSH2_MSG_KEXGSS_INIT);
				packet_put_string(send_tok.value,
				    send_tok.length);
				packet_put_bignum2(dh->pub_key);
				first = 0;
			} else {
				packet_start(SSH2_MSG_KEXGSS_CONTINUE);
				packet_put_string(send_tok.value,
				    send_tok.length);
			}
			packet_send();
			gss_release_buffer(&min_status, &send_tok);

			/* If we've sent them data, they should reply */
			do {	
				type = packet_read();
				if (type == SSH2_MSG_KEXGSS_HOSTKEY) {
					debug("Received KEXGSS_HOSTKEY");
					if (serverhostkey)
						fatal("Server host key received more than once");
					serverhostkey = 
					    packet_get_string(&slen);
				}
			} while (type == SSH2_MSG_KEXGSS_HOSTKEY);

			switch (type) {
			case SSH2_MSG_KEXGSS_CONTINUE:
				debug("Received GSSAPI_CONTINUE");
				if (maj_status == GSS_S_COMPLETE) 
					fatal("GSSAPI Continue received from server when complete");
				recv_tok.value = packet_get_string(&strlen);
				recv_tok.length = strlen; 
				break;
			case SSH2_MSG_KEXGSS_COMPLETE:
				debug("Received GSSAPI_COMPLETE");
				packet_get_bignum2(dh_server_pub);
				msg_tok.value =  packet_get_string(&strlen);
				msg_tok.length = strlen; 

				/* Is there a token included? */
				if (packet_get_char()) {
					recv_tok.value=
					    packet_get_string(&strlen);
					recv_tok.length = strlen;
					/* If we're already complete - protocol error */
					if (maj_status == GSS_S_COMPLETE)
						packet_disconnect("Protocol error: received token when complete");
					} else {
						/* No token included */
						if (maj_status != GSS_S_COMPLETE)
							packet_disconnect("Protocol error: did not receive final token");
				}
				break;
			case SSH2_MSG_KEXGSS_ERROR:
				debug("Received Error");
				maj_status = packet_get_int();
				min_status = packet_get_int();
				msg = packet_get_string(NULL);
				lang = packet_get_string(NULL);
				fatal("GSSAPI Error: \n%.400s",msg);
			default:
				packet_disconnect("Protocol error: didn't expect packet type %d",
		    		type);
			}
			token_ptr = &recv_tok;
		} else {
			/* No data, and not complete */
			if (maj_status != GSS_S_COMPLETE)
				fatal("Not complete, and no token output");
		}
	} while (maj_status & GSS_S_CONTINUE_NEEDED);

	/* 
	 * We _must_ have received a COMPLETE message in reply from the 
	 * server, which will have set dh_server_pub and msg_tok 
	 */

	if (type != SSH2_MSG_KEXGSS_COMPLETE)
		fatal("Didn't receive a SSH2_MSG_KEXGSS_COMPLETE when I expected it");

	/* Check f in range [1, p-1] */
	if (!dh_pub_is_valid(dh, dh_server_pub))
		packet_disconnect("bad server public DH value");

	/* compute K=f^x mod p */
	klen = DH_size(dh);
	kbuf = xmalloc(klen);
	kout = DH_compute_key(kbuf, dh_server_pub, dh);

	shared_secret = BN_new();
	BN_bin2bn(kbuf,kout, shared_secret);
	memset(kbuf, 0, klen);
	xfree(kbuf);

	switch (kex->kex_type) {
	case KEX_GSS_GRP1_SHA1:
	case KEX_GSS_GRP14_SHA1:
		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),
		    serverhostkey, slen, /* server host key */
		    dh->pub_key,	/* e */
		    dh_server_pub,	/* f */
		    shared_secret,	/* K */
		    &hash, &hashlen
		);
		break;
	case KEX_GSS_GEX_SHA1:
		kexgex_hash(
		    kex->evp_md,
		    kex->client_version_string,
		    kex->server_version_string,
		    buffer_ptr(&kex->my), buffer_len(&kex->my),
		    buffer_ptr(&kex->peer), buffer_len(&kex->peer),
		    serverhostkey, slen,
 		    min, nbits, max,
		    dh->p, dh->g,
		    dh->pub_key,
		    dh_server_pub,
		    shared_secret,
		    &hash, &hashlen
		);
		break;
	default:
		fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
	}

	gssbuf.value = hash;
	gssbuf.length = hashlen;

	/* Verify that the hash matches the MIC we just got. */
	if (GSS_ERROR(ssh_gssapi_checkmic(ctxt, &gssbuf, &msg_tok)))
		packet_disconnect("Hash's MIC didn't verify");

	xfree(msg_tok.value);

	DH_free(dh);
	if (serverhostkey)
		xfree(serverhostkey);
	BN_clear_free(dh_server_pub);

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

	if (gss_kex_context == NULL)
		gss_kex_context = ctxt;
	else
		ssh_gssapi_delete_ctx(&ctxt);

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

#endif /* GSSAPI */
Commit	Line	Data
1c14df9e	1	/*
2e437378	2	* Copyright (c) 2001-2006 Simon Wilkinson. All rights reserved.
1c14df9e	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"
	26
	27	#ifdef GSSAPI
	28
	29	#include <openssl/crypto.h>
	30	#include <openssl/bn.h>
	31
2e437378	32	#include <string.h>
2e437378	33
1c14df9e	34	#include "xmalloc.h"
1c14df9e	35	#include "buffer.h"
2e437378	36	#include "ssh2.h"
	37	#include "key.h"
	38	#include "cipher.h"
1c14df9e	39	#include "kex.h"
	40	#include "log.h"
	41	#include "packet.h"
	42	#include "dh.h"
2e437378	43
1c14df9e	44	#include "ssh-gss.h"
1c14df9e	45
1c14df9e	46	void
34fee935	47	kexgss_client(Kex *kex) {
34fee935	48	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
2e437378	49	gss_buffer_desc recv_tok, gssbuf, msg_tok, *token_ptr;
1c14df9e	50	Gssctxt *ctxt;
1c14df9e	51	OM_uint32 maj_status, min_status, ret_flags;
e00da40d	52	u_int klen, kout, slen = 0, hashlen, strlen;
1c14df9e	53	DH *dh;
34fee935	54	BIGNUM *dh_server_pub = NULL;
	55	BIGNUM *shared_secret = NULL;
	56	BIGNUM *p = NULL;
	57	BIGNUM *g = NULL;
e00da40d	58	u_char kbuf, hash;
e00da40d	59	u_char *serverhostkey = NULL;
88928908	60	char *msg;
88928908	61	char *lang;
1c14df9e	62	int type = 0;
1c14df9e	63	int first = 1;
e00da40d	64	int nbits = 0, min = DH_GRP_MIN, max = DH_GRP_MAX;
34fee935	65
34fee935	66	/* Initialise our GSSAPI world */
1c14df9e	67	ssh_gssapi_build_ctx(&ctxt);
2e437378	68	if (ssh_gssapi_id_kex(ctxt, kex->name, kex->kex_type)
2e437378	69	== GSS_C_NO_OID)
1c14df9e	70	fatal("Couldn't identify host exchange");
8bb69cbe	71
34fee935	72	if (ssh_gssapi_import_name(ctxt, kex->gss_host))
	73	fatal("Couldn't import hostname");
	74
2e437378	75	switch (kex->kex_type) {
	76	case KEX_GSS_GRP1_SHA1:
	77	dh = dh_new_group1();
	78	break;
	79	case KEX_GSS_GRP14_SHA1:
	80	dh = dh_new_group14();
	81	break;
	82	case KEX_GSS_GEX_SHA1:
34fee935	83	debug("Doing group exchange\n");
34fee935	84	nbits = dh_estimate(kex->we_need * 8);
34fee935	85	packet_start(SSH2_MSG_KEXGSS_GROUPREQ);
	86	packet_put_int(min);
	87	packet_put_int(nbits);
	88	packet_put_int(max);
	89
	90	packet_send();
	91
	92	packet_read_expect(SSH2_MSG_KEXGSS_GROUP);
	93
	94	if ((p = BN_new()) == NULL)
	95	fatal("BN_new() failed");
	96	packet_get_bignum2(p);
	97	if ((g = BN_new()) == NULL)
	98	fatal("BN_new() failed");
	99	packet_get_bignum2(g);
	100	packet_check_eom();
	101
	102	if (BN_num_bits(p) < min \|\| BN_num_bits(p) > max)
	103	fatal("GSSGRP_GEX group out of range: %d !< %d !< %d",
	104	min, BN_num_bits(p), max);
	105
	106	dh = dh_new_group(g, p);
2e437378	107	break;
	108	default:
	109	fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
1c14df9e	110	}
1c14df9e	111
1c14df9e	112	/* Step 1 - e is dh->pub_key */
1c14df9e	113	dh_gen_key(dh, kex->we_need * 8);
	114
	115	/* This is f, we initialise it now to make life easier */
34fee935	116	dh_server_pub = BN_new();
	117	if (dh_server_pub == NULL)
	118	fatal("dh_server_pub == NULL");
	119
1c14df9e	120	token_ptr = GSS_C_NO_BUFFER;
	121
	122	do {
	123	debug("Calling gss_init_sec_context");
	124
34fee935	125	maj_status = ssh_gssapi_init_ctx(ctxt,
	126	kex->gss_deleg_creds, token_ptr, &send_tok,
	127	&ret_flags);
1c14df9e	128
1c14df9e	129	if (GSS_ERROR(maj_status)) {
34fee935	130	if (send_tok.length != 0) {
88928908	131	packet_start(SSH2_MSG_KEXGSS_CONTINUE);
88928908	132	packet_put_string(send_tok.value,
34fee935	133	send_tok.length);
34fee935	134	}
1c14df9e	135	fatal("gss_init_context failed");
88928908	136	}
1c14df9e	137
	138	/* If we've got an old receive buffer get rid of it */
	139	if (token_ptr != GSS_C_NO_BUFFER)
34fee935	140	xfree(recv_tok.value);
34fee935	141
1c14df9e	142	if (maj_status == GSS_S_COMPLETE) {
1c14df9e	143	/* If mutual state flag is not true, kex fails */
34fee935	144	if (!(ret_flags & GSS_C_MUTUAL_FLAG))
1c14df9e	145	fatal("Mutual authentication failed");
34fee935	146
1c14df9e	147	/* If integ avail flag is not true kex fails */
34fee935	148	if (!(ret_flags & GSS_C_INTEG_FLAG))
1c14df9e	149	fatal("Integrity check failed");
1c14df9e	150	}
34fee935	151
	152	/*
	153	* If we have data to send, then the last message that we
	154	* received cannot have been a 'complete'.
	155	*/
	156	if (send_tok.length != 0) {
1c14df9e	157	if (first) {
	158	packet_start(SSH2_MSG_KEXGSS_INIT);
	159	packet_put_string(send_tok.value,
34fee935	160	send_tok.length);
1c14df9e	161	packet_put_bignum2(dh->pub_key);
34fee935	162	first = 0;
1c14df9e	163	} else {
	164	packet_start(SSH2_MSG_KEXGSS_CONTINUE);
	165	packet_put_string(send_tok.value,
34fee935	166	send_tok.length);
1c14df9e	167	}
1c14df9e	168	packet_send();
34fee935	169	gss_release_buffer(&min_status, &send_tok);
	170
	171	/* If we've sent them data, they should reply */
	172	do {
	173	type = packet_read();
	174	if (type == SSH2_MSG_KEXGSS_HOSTKEY) {
	175	debug("Received KEXGSS_HOSTKEY");
	176	if (serverhostkey)
	177	fatal("Server host key received more than once");
	178	serverhostkey =
	179	packet_get_string(&slen);
	180	}
	181	} while (type == SSH2_MSG_KEXGSS_HOSTKEY);
1c14df9e	182
1c14df9e	183	switch (type) {
1c14df9e	184	case SSH2_MSG_KEXGSS_CONTINUE:
	185	debug("Received GSSAPI_CONTINUE");
	186	if (maj_status == GSS_S_COMPLETE)
	187	fatal("GSSAPI Continue received from server when complete");
34fee935	188	recv_tok.value = packet_get_string(&strlen);
34fee935	189	recv_tok.length = strlen;
1c14df9e	190	break;
	191	case SSH2_MSG_KEXGSS_COMPLETE:
	192	debug("Received GSSAPI_COMPLETE");
34fee935	193	packet_get_bignum2(dh_server_pub);
	194	msg_tok.value = packet_get_string(&strlen);
	195	msg_tok.length = strlen;
1c14df9e	196
	197	/* Is there a token included? */
	198	if (packet_get_char()) {
	199	recv_tok.value=
88928908	200	packet_get_string(&strlen);
34fee935	201	recv_tok.length = strlen;
1c14df9e	202	/* If we're already complete - protocol error */
	203	if (maj_status == GSS_S_COMPLETE)
	204	packet_disconnect("Protocol error: received token when complete");
34fee935	205	} else {
	206	/* No token included */
	207	if (maj_status != GSS_S_COMPLETE)
	208	packet_disconnect("Protocol error: did not receive final token");
1c14df9e	209	}
1c14df9e	210	break;
88928908	211	case SSH2_MSG_KEXGSS_ERROR:
88928908	212	debug("Received Error");
34fee935	213	maj_status = packet_get_int();
	214	min_status = packet_get_int();
	215	msg = packet_get_string(NULL);
	216	lang = packet_get_string(NULL);
2e437378	217	fatal("GSSAPI Error: \n%.400s",msg);
1c14df9e	218	default:
	219	packet_disconnect("Protocol error: didn't expect packet type %d",
	220	type);
	221	}
34fee935	222	token_ptr = &recv_tok;
88928908	223	} else {
88928908	224	/* No data, and not complete */
34fee935	225	if (maj_status != GSS_S_COMPLETE)
88928908	226	fatal("Not complete, and no token output");
1c14df9e	227	}
34fee935	228	} while (maj_status & GSS_S_CONTINUE_NEEDED);
	229
	230	/*
	231	* We _must_ have received a COMPLETE message in reply from the
	232	* server, which will have set dh_server_pub and msg_tok
	233	*/
	234
	235	if (type != SSH2_MSG_KEXGSS_COMPLETE)
	236	fatal("Didn't receive a SSH2_MSG_KEXGSS_COMPLETE when I expected it");
	237
1c14df9e	238	/* Check f in range [1, p-1] */
34fee935	239	if (!dh_pub_is_valid(dh, dh_server_pub))
34fee935	240	packet_disconnect("bad server public DH value");
1c14df9e	241
34fee935	242	/* compute K=f^x mod p */
	243	klen = DH_size(dh);
	244	kbuf = xmalloc(klen);
	245	kout = DH_compute_key(kbuf, dh_server_pub, dh);
	246
	247	shared_secret = BN_new();
	248	BN_bin2bn(kbuf,kout, shared_secret);
	249	memset(kbuf, 0, klen);
	250	xfree(kbuf);
	251
2e437378	252	switch (kex->kex_type) {
	253	case KEX_GSS_GRP1_SHA1:
	254	case KEX_GSS_GRP14_SHA1:
	255	kex_dh_hash( kex->client_version_string,
	256	kex->server_version_string,
	257	buffer_ptr(&kex->my), buffer_len(&kex->my),
	258	buffer_ptr(&kex->peer), buffer_len(&kex->peer),
	259	serverhostkey, slen, /* server host key */
	260	dh->pub_key, /* e */
	261	dh_server_pub, /* f */
	262	shared_secret, /* K */
	263	&hash, &hashlen
	264	);
	265	break;
	266	case KEX_GSS_GEX_SHA1:
e00da40d	267	kexgex_hash(
	268	kex->evp_md,
	269	kex->client_version_string,
34fee935	270	kex->server_version_string,
	271	buffer_ptr(&kex->my), buffer_len(&kex->my),
	272	buffer_ptr(&kex->peer), buffer_len(&kex->peer),
	273	serverhostkey, slen,
	274	min, nbits, max,
	275	dh->p, dh->g,
	276	dh->pub_key,
	277	dh_server_pub,
e00da40d	278	shared_secret,
e00da40d	279	&hash, &hashlen
34fee935	280	);
2e437378	281	break;
	282	default:
	283	fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
	284	}
34fee935	285
34fee935	286	gssbuf.value = hash;
e00da40d	287	gssbuf.length = hashlen;
34fee935	288
2e437378	289	/* Verify that the hash matches the MIC we just got. */
34fee935	290	if (GSS_ERROR(ssh_gssapi_checkmic(ctxt, &gssbuf, &msg_tok)))
	291	packet_disconnect("Hash's MIC didn't verify");
	292
	293	xfree(msg_tok.value);
	294
	295	DH_free(dh);
	296	if (serverhostkey)
	297	xfree(serverhostkey);
	298	BN_clear_free(dh_server_pub);
	299
	300	/* save session id */
	301	if (kex->session_id == NULL) {
e00da40d	302	kex->session_id_len = hashlen;
34fee935	303	kex->session_id = xmalloc(kex->session_id_len);
	304	memcpy(kex->session_id, hash, kex->session_id_len);
	305	}
	306
	307	if (gss_kex_context == NULL)
	308	gss_kex_context = ctxt;
	309	else
	310	ssh_gssapi_delete_ctx(&ctxt);
	311
e00da40d	312	kex_derive_keys(kex, hash, hashlen, shared_secret);
1c14df9e	313	BN_clear_free(shared_secret);
34fee935	314	kex_finish(kex);
1c14df9e	315	}
	316
	317	#endif /* GSSAPI */