[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 "includes.h"

#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
d617aef3	1	/*
	2	* Copyright (c) 2001-2006 Simon Wilkinson. 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"
	26
	27	#ifdef GSSAPI
	28
	29	#include "includes.h"
	30
	31	#include <openssl/crypto.h>
	32	#include <openssl/bn.h>
	33
	34	#include <string.h>
	35
	36	#include "xmalloc.h"
	37	#include "buffer.h"
	38	#include "ssh2.h"
	39	#include "key.h"
	40	#include "cipher.h"
	41	#include "kex.h"
	42	#include "log.h"
	43	#include "packet.h"
	44	#include "dh.h"
	45
	46	#include "ssh-gss.h"
	47
	48	void
	49	kexgss_client(Kex *kex) {
	50	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	51	gss_buffer_desc recv_tok, gssbuf, msg_tok, *token_ptr;
	52	Gssctxt *ctxt;
	53	OM_uint32 maj_status, min_status, ret_flags;
	54	u_int klen, kout, slen = 0, hashlen, strlen;
	55	DH *dh;
	56	BIGNUM *dh_server_pub = NULL;
	57	BIGNUM *shared_secret = NULL;
	58	BIGNUM *p = NULL;
	59	BIGNUM *g = NULL;
	60	u_char kbuf, hash;
	61	u_char *serverhostkey = NULL;
	62	char *msg;
	63	char *lang;
	64	int type = 0;
65	int first = 1;
66	int nbits = 0, min = DH_GRP_MIN, max = DH_GRP_MAX;
67
68	/* Initialise our GSSAPI world */
69	ssh_gssapi_build_ctx(&ctxt);
70	if (ssh_gssapi_id_kex(ctxt, kex->name, kex->kex_type)
71	== GSS_C_NO_OID)
72	fatal("Couldn't identify host exchange");
73
74	if (ssh_gssapi_import_name(ctxt, kex->gss_host))
75	fatal("Couldn't import hostname");
76
77	switch (kex->kex_type) {
78	case KEX_GSS_GRP1_SHA1:
79	dh = dh_new_group1();
80	break;
81	case KEX_GSS_GRP14_SHA1:
82	dh = dh_new_group14();
83	break;
84	case KEX_GSS_GEX_SHA1:
85	debug("Doing group exchange\n");
86	nbits = dh_estimate(kex->we_need * 8);
87	packet_start(SSH2_MSG_KEXGSS_GROUPREQ);
88	packet_put_int(min);
89	packet_put_int(nbits);
90	packet_put_int(max);
91
92	packet_send();
93
94	packet_read_expect(SSH2_MSG_KEXGSS_GROUP);
95
96	if ((p = BN_new()) == NULL)
97	fatal("BN_new() failed");
98	packet_get_bignum2(p);
99	if ((g = BN_new()) == NULL)
100	fatal("BN_new() failed");
101	packet_get_bignum2(g);
102	packet_check_eom();
103
104	if (BN_num_bits(p) < min \|\| BN_num_bits(p) > max)
105	fatal("GSSGRP_GEX group out of range: %d !< %d !< %d",
106	min, BN_num_bits(p), max);
107
108	dh = dh_new_group(g, p);
109	break;
110	default:
111	fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
112	}
113
114	/* Step 1 - e is dh->pub_key */
115	dh_gen_key(dh, kex->we_need * 8);
116
117	/* This is f, we initialise it now to make life easier */
118	dh_server_pub = BN_new();
119	if (dh_server_pub == NULL)
120	fatal("dh_server_pub == NULL");
121
122	token_ptr = GSS_C_NO_BUFFER;
123
124	do {
125	debug("Calling gss_init_sec_context");
126
127	maj_status = ssh_gssapi_init_ctx(ctxt,
128	kex->gss_deleg_creds, token_ptr, &send_tok,
129	&ret_flags);
130
131	if (GSS_ERROR(maj_status)) {
132	if (send_tok.length != 0) {
133	packet_start(SSH2_MSG_KEXGSS_CONTINUE);
134	packet_put_string(send_tok.value,
135	send_tok.length);
136	}
137	fatal("gss_init_context failed");
138	}
139
140	/* If we've got an old receive buffer get rid of it */
141	if (token_ptr != GSS_C_NO_BUFFER)
142	xfree(recv_tok.value);
143
144	if (maj_status == GSS_S_COMPLETE) {
145	/* If mutual state flag is not true, kex fails */
146	if (!(ret_flags & GSS_C_MUTUAL_FLAG))
147	fatal("Mutual authentication failed");
148
149	/* If integ avail flag is not true kex fails */
150	if (!(ret_flags & GSS_C_INTEG_FLAG))
151	fatal("Integrity check failed");
152	}
153
154	/*
155	* If we have data to send, then the last message that we
156	* received cannot have been a 'complete'.
157	*/
158	if (send_tok.length != 0) {
159	if (first) {
160	packet_start(SSH2_MSG_KEXGSS_INIT);
161	packet_put_string(send_tok.value,
162	send_tok.length);
163	packet_put_bignum2(dh->pub_key);
164	first = 0;
165	} else {
166	packet_start(SSH2_MSG_KEXGSS_CONTINUE);
167	packet_put_string(send_tok.value,
168	send_tok.length);
169	}
170	packet_send();
171	gss_release_buffer(&min_status, &send_tok);
172
173	/* If we've sent them data, they should reply */
174	do {
175	type = packet_read();
176	if (type == SSH2_MSG_KEXGSS_HOSTKEY) {
177	debug("Received KEXGSS_HOSTKEY");
178	if (serverhostkey)
179	fatal("Server host key received more than once");
180	serverhostkey =
181	packet_get_string(&slen);
182	}
183	} while (type == SSH2_MSG_KEXGSS_HOSTKEY);
184
185	switch (type) {
186	case SSH2_MSG_KEXGSS_CONTINUE:
187	debug("Received GSSAPI_CONTINUE");
188	if (maj_status == GSS_S_COMPLETE)
189	fatal("GSSAPI Continue received from server when complete");
190	recv_tok.value = packet_get_string(&strlen);
191	recv_tok.length = strlen;
192	break;
193	case SSH2_MSG_KEXGSS_COMPLETE:
194	debug("Received GSSAPI_COMPLETE");
195	packet_get_bignum2(dh_server_pub);
196	msg_tok.value = packet_get_string(&strlen);
197	msg_tok.length = strlen;
198
199	/* Is there a token included? */
200	if (packet_get_char()) {
201	recv_tok.value=
202	packet_get_string(&strlen);
203	recv_tok.length = strlen;
204	/* If we're already complete - protocol error */
205	if (maj_status == GSS_S_COMPLETE)
206	packet_disconnect("Protocol error: received token when complete");
207	} else {
208	/* No token included */
209	if (maj_status != GSS_S_COMPLETE)
210	packet_disconnect("Protocol error: did not receive final token");
211	}
212	break;
213	case SSH2_MSG_KEXGSS_ERROR:
214	debug("Received Error");
215	maj_status = packet_get_int();
216	min_status = packet_get_int();
217	msg = packet_get_string(NULL);
218	lang = packet_get_string(NULL);
219	fatal("GSSAPI Error: \n%.400s",msg);
220	default:
221	packet_disconnect("Protocol error: didn't expect packet type %d",
222	type);
223	}
224	token_ptr = &recv_tok;
225	} else {
226	/* No data, and not complete */
227	if (maj_status != GSS_S_COMPLETE)
228	fatal("Not complete, and no token output");
229	}
230	} while (maj_status & GSS_S_CONTINUE_NEEDED);
231
232	/*
233	* We _must_ have received a COMPLETE message in reply from the
234	* server, which will have set dh_server_pub and msg_tok
235	*/
236
237	if (type != SSH2_MSG_KEXGSS_COMPLETE)
238	fatal("Didn't receive a SSH2_MSG_KEXGSS_COMPLETE when I expected it");
239
240	/* Check f in range [1, p-1] */
241	if (!dh_pub_is_valid(dh, dh_server_pub))
242	packet_disconnect("bad server public DH value");
243
244	/* compute K=f^x mod p */
245	klen = DH_size(dh);
246	kbuf = xmalloc(klen);
247	kout = DH_compute_key(kbuf, dh_server_pub, dh);
248
249	shared_secret = BN_new();
250	BN_bin2bn(kbuf,kout, shared_secret);
251	memset(kbuf, 0, klen);
252	xfree(kbuf);
253
254	switch (kex->kex_type) {
255	case KEX_GSS_GRP1_SHA1:
256	case KEX_GSS_GRP14_SHA1:
257	kex_dh_hash( kex->client_version_string,
258	kex->server_version_string,
259	buffer_ptr(&kex->my), buffer_len(&kex->my),
260	buffer_ptr(&kex->peer), buffer_len(&kex->peer),
261	serverhostkey, slen, /* server host key */
262	dh->pub_key, /* e */
263	dh_server_pub, /* f */
264	shared_secret, /* K */
265	&hash, &hashlen
266	);
267	break;
268	case KEX_GSS_GEX_SHA1:
269	kexgex_hash(
270	kex->evp_md,
271	kex->client_version_string,
272	kex->server_version_string,
273	buffer_ptr(&kex->my), buffer_len(&kex->my),
274	buffer_ptr(&kex->peer), buffer_len(&kex->peer),
275	serverhostkey, slen,
276	min, nbits, max,
277	dh->p, dh->g,
278	dh->pub_key,
279	dh_server_pub,
280	shared_secret,
281	&hash, &hashlen
282	);
283	break;
284	default:
285	fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
286	}
287
288	gssbuf.value = hash;
289	gssbuf.length = hashlen;
290
291	/* Verify that the hash matches the MIC we just got. */
292	if (GSS_ERROR(ssh_gssapi_checkmic(ctxt, &gssbuf, &msg_tok)))
293	packet_disconnect("Hash's MIC didn't verify");
294
295	xfree(msg_tok.value);
296
297	DH_free(dh);
298	if (serverhostkey)
299	xfree(serverhostkey);
300	BN_clear_free(dh_server_pub);
301
302	/* save session id */
303	if (kex->session_id == NULL) {
304	kex->session_id_len = hashlen;
305	kex->session_id = xmalloc(kex->session_id_len);
306	memcpy(kex->session_id, hash, kex->session_id_len);
307	}
308
309	if (gss_kex_context == NULL)
310	gss_kex_context = ctxt;
311	else
312	ssh_gssapi_delete_ctx(&ctxt);
313
314	kex_derive_keys(kex, hash, hashlen, shared_secret);
315	BN_clear_free(shared_secret);
316	kex_finish(kex);
317	}
318
319	#endif /* GSSAPI */