[openssh.git] / auth2-gss.c

/* $OpenBSD: auth2-gss.c,v 1.15 2006/08/03 03:34:41 deraadt Exp $ */

/*
 * Copyright (c) 2001-2003 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"

#include <sys/types.h>

#include "xmalloc.h"
#include "key.h"
#include "hostfile.h"
#include "auth.h"
#include "ssh2.h"
#include "log.h"
#include "dispatch.h"
#include "buffer.h"
#include "servconf.h"
#include "packet.h"
#include "ssh-gss.h"
#include "monitor_wrap.h"

extern ServerOptions options;

static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt);
static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
static void input_gssapi_errtok(int, u_int32_t, void *);

/*
 * We only support those mechanisms that we know about (ie ones that we know
 * how to check local user kuserok and the like)
 */
static int
userauth_gssapi(Authctxt *authctxt)
{
	gss_OID_desc goid = {0, NULL};
	Gssctxt *ctxt = NULL;
	int mechs;
	gss_OID_set supported;
	int present;
	OM_uint32 ms;
	u_int len;
	u_char *doid = NULL;

	if (!authctxt->valid || authctxt->user == NULL)
		return (0);

	mechs = packet_get_int();
	if (mechs == 0) {
		debug("Mechanism negotiation is not supported");
		return (0);
	}

	ssh_gssapi_supported_oids(&supported);
	do {
		mechs--;

		if (doid)
			xfree(doid);

		present = 0;
		doid = packet_get_string(&len);

		if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
		    doid[1] == len - 2) {
			goid.elements = doid + 2;
			goid.length   = len - 2;
			gss_test_oid_set_member(&ms, &goid, supported,
			    &present);
		} else {
			logit("Badly formed OID received");
		}
	} while (mechs > 0 && !present);

	gss_release_oid_set(&ms, &supported);

	if (!present) {
		xfree(doid);
		return (0);
	}

	if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
		if (ctxt != NULL)
			ssh_gssapi_delete_ctx(&ctxt);
		xfree(doid);
		return (0);
	}

	authctxt->methoddata = (void *)ctxt;

	packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);

	/* Return the OID that we received */
	packet_put_string(doid, len);

	packet_send();
	xfree(doid);

	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
	authctxt->postponed = 1;

	return (0);
}

static void
input_gssapi_token(int type, u_int32_t plen, void *ctxt)
{
	Authctxt *authctxt = ctxt;
	Gssctxt *gssctxt;
	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	gss_buffer_desc recv_tok;
	OM_uint32 maj_status, min_status, flags;
	u_int len;

	if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
		fatal("No authentication or GSSAPI context");

	gssctxt = authctxt->methoddata;
	recv_tok.value = packet_get_string(&len);
	recv_tok.length = len; /* u_int vs. size_t */

	packet_check_eom();

	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
	    &send_tok, &flags));

	xfree(recv_tok.value);

	if (GSS_ERROR(maj_status)) {
		if (send_tok.length != 0) {
			packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
			packet_put_string(send_tok.value, send_tok.length);
			packet_send();
		}
		authctxt->postponed = 0;
		dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
		userauth_finish(authctxt, 0, "gssapi-with-mic");
	} else {
		if (send_tok.length != 0) {
			packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
			packet_put_string(send_tok.value, send_tok.length);
			packet_send();
		}
		if (maj_status == GSS_S_COMPLETE) {
			dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
			if (flags & GSS_C_INTEG_FLAG)
				dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
				    &input_gssapi_mic);
			else
				dispatch_set(
				    SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
				    &input_gssapi_exchange_complete);
		}
	}

	gss_release_buffer(&min_status, &send_tok);
}

static void
input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
{
	Authctxt *authctxt = ctxt;
	Gssctxt *gssctxt;
	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	gss_buffer_desc recv_tok;
	OM_uint32 maj_status;
	u_int len;

	if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
		fatal("No authentication or GSSAPI context");

	gssctxt = authctxt->methoddata;
	recv_tok.value = packet_get_string(&len);
	recv_tok.length = len;

	packet_check_eom();

	/* Push the error token into GSSAPI to see what it says */
	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
	    &send_tok, NULL));

	xfree(recv_tok.value);

	/* We can't return anything to the client, even if we wanted to */
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);

	/* The client will have already moved on to the next auth */

	gss_release_buffer(&maj_status, &send_tok);
}

/*
 * This is called when the client thinks we've completed authentication.
 * It should only be enabled in the dispatch handler by the function above,
 * which only enables it once the GSSAPI exchange is complete.
 */

static void
input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
{
	Authctxt *authctxt = ctxt;
	Gssctxt *gssctxt;
	int authenticated;

	if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
		fatal("No authentication or GSSAPI context");

	gssctxt = authctxt->methoddata;

	/*
	 * We don't need to check the status, because we're only enabled in
	 * the dispatcher once the exchange is complete
	 */

	packet_check_eom();

	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));

	authctxt->postponed = 0;
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
	userauth_finish(authctxt, authenticated, "gssapi-with-mic");
}

static void
input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
{
	Authctxt *authctxt = ctxt;
	Gssctxt *gssctxt;
	int authenticated = 0;
	Buffer b;
	gss_buffer_desc mic, gssbuf;
	u_int len;

	if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
		fatal("No authentication or GSSAPI context");

	gssctxt = authctxt->methoddata;

	mic.value = packet_get_string(&len);
	mic.length = len;

	ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
	    "gssapi-with-mic");

	gssbuf.value = buffer_ptr(&b);
	gssbuf.length = buffer_len(&b);

	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
		authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	else
		logit("GSSAPI MIC check failed");

	buffer_free(&b);
	xfree(mic.value);

	authctxt->postponed = 0;
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
	userauth_finish(authctxt, authenticated, "gssapi-with-mic");
}

Authmethod method_gssapi = {
	"gssapi-with-mic",
	userauth_gssapi,
	&options.gss_authentication
};
Commit	Line	Data
31652869	1	/* $OpenBSD: auth2-gss.c,v 1.15 2006/08/03 03:34:41 deraadt Exp $ */
7364bd04	2
	3	/*
	4	* Copyright (c) 2001-2003 Simon Wilkinson. 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
	27	#include "includes.h"
	28
31652869	29	#include <sys/types.h>
7364bd04	30
31652869	31	#include "xmalloc.h"
	32	#include "key.h"
	33	#include "hostfile.h"
7364bd04	34	#include "auth.h"
7364bd04	35	#include "ssh2.h"
7364bd04	36	#include "log.h"
7364bd04	37	#include "dispatch.h"
31652869	38	#include "buffer.h"
7364bd04	39	#include "servconf.h"
7364bd04	40	#include "packet.h"
7364bd04	41	#include "ssh-gss.h"
31652869	42	#include "monitor_wrap.h"
7364bd04	43
	44	extern ServerOptions options;
	45
	46	static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
0789992b	47	static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt);
7364bd04	48	static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
	49	static void input_gssapi_errtok(int, u_int32_t, void *);
	50
	51	/*
	52	* We only support those mechanisms that we know about (ie ones that we know
8442cc66	53	* how to check local user kuserok and the like)
7364bd04	54	*/
	55	static int
	56	userauth_gssapi(Authctxt *authctxt)
	57	{
ca75d7de	58	gss_OID_desc goid = {0, NULL};
7364bd04	59	Gssctxt *ctxt = NULL;
	60	int mechs;
	61	gss_OID_set supported;
	62	int present;
	63	OM_uint32 ms;
	64	u_int len;
2ceb8101	65	u_char *doid = NULL;
7364bd04	66
	67	if (!authctxt->valid \|\| authctxt->user == NULL)
	68	return (0);
	69
	70	mechs = packet_get_int();
	71	if (mechs == 0) {
	72	debug("Mechanism negotiation is not supported");
	73	return (0);
	74	}
	75
	76	ssh_gssapi_supported_oids(&supported);
	77	do {
	78	mechs--;
	79
	80	if (doid)
	81	xfree(doid);
	82
d8d9afd0	83	present = 0;
7364bd04	84	doid = packet_get_string(&len);
7364bd04	85
4e2e5cfd	86	if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
4e2e5cfd	87	doid[1] == len - 2) {
ca75d7de	88	goid.elements = doid + 2;
	89	goid.length = len - 2;
	90	gss_test_oid_set_member(&ms, &goid, supported,
d8d9afd0	91	&present);
7364bd04	92	} else {
d8d9afd0	93	logit("Badly formed OID received");
7364bd04	94	}
7364bd04	95	} while (mechs > 0 && !present);
	96
	97	gss_release_oid_set(&ms, &supported);
	98
	99	if (!present) {
	100	xfree(doid);
	101	return (0);
	102	}
	103
ca75d7de	104	if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
0fa53840	105	if (ctxt != NULL)
0fa53840	106	ssh_gssapi_delete_ctx(&ctxt);
4771605b	107	xfree(doid);
7364bd04	108	return (0);
4771605b	109	}
7364bd04	110
8442cc66	111	authctxt->methoddata = (void *)ctxt;
7364bd04	112
	113	packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
	114
d8d9afd0	115	/* Return the OID that we received */
7364bd04	116	packet_put_string(doid, len);
	117
	118	packet_send();
	119	xfree(doid);
	120
	121	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
	122	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
	123	authctxt->postponed = 1;
	124
	125	return (0);
	126	}
	127
	128	static void
	129	input_gssapi_token(int type, u_int32_t plen, void *ctxt)
	130	{
	131	Authctxt *authctxt = ctxt;
	132	Gssctxt *gssctxt;
	133	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	134	gss_buffer_desc recv_tok;
0789992b	135	OM_uint32 maj_status, min_status, flags;
7364bd04	136	u_int len;
	137
	138	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	139	fatal("No authentication or GSSAPI context");
	140
	141	gssctxt = authctxt->methoddata;
	142	recv_tok.value = packet_get_string(&len);
	143	recv_tok.length = len; /* u_int vs. size_t */
	144
	145	packet_check_eom();
	146
	147	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
0789992b	148	&send_tok, &flags));
7364bd04	149
	150	xfree(recv_tok.value);
	151
	152	if (GSS_ERROR(maj_status)) {
	153	if (send_tok.length != 0) {
	154	packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
	155	packet_put_string(send_tok.value, send_tok.length);
	156	packet_send();
	157	}
	158	authctxt->postponed = 0;
	159	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
0789992b	160	userauth_finish(authctxt, 0, "gssapi-with-mic");
7364bd04	161	} else {
	162	if (send_tok.length != 0) {
	163	packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
	164	packet_put_string(send_tok.value, send_tok.length);
	165	packet_send();
	166	}
	167	if (maj_status == GSS_S_COMPLETE) {
	168	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
0789992b	169	if (flags & GSS_C_INTEG_FLAG)
	170	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
	171	&input_gssapi_mic);
	172	else
	173	dispatch_set(
	174	SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
	175	&input_gssapi_exchange_complete);
7364bd04	176	}
	177	}
	178
	179	gss_release_buffer(&min_status, &send_tok);
	180	}
	181
	182	static void
	183	input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
	184	{
	185	Authctxt *authctxt = ctxt;
	186	Gssctxt *gssctxt;
	187	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	188	gss_buffer_desc recv_tok;
	189	OM_uint32 maj_status;
eb18f58d	190	u_int len;
7364bd04	191
	192	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	193	fatal("No authentication or GSSAPI context");
	194
	195	gssctxt = authctxt->methoddata;
eb18f58d	196	recv_tok.value = packet_get_string(&len);
eb18f58d	197	recv_tok.length = len;
7364bd04	198
	199	packet_check_eom();
	200
	201	/* Push the error token into GSSAPI to see what it says */
	202	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
	203	&send_tok, NULL));
	204
	205	xfree(recv_tok.value);
	206
	207	/* We can't return anything to the client, even if we wanted to */
	208	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	209	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
	210
	211	/* The client will have already moved on to the next auth */
	212
	213	gss_release_buffer(&maj_status, &send_tok);
	214	}
	215
	216	/*
	217	* This is called when the client thinks we've completed authentication.
	218	* It should only be enabled in the dispatch handler by the function above,
	219	* which only enables it once the GSSAPI exchange is complete.
	220	*/
	221
	222	static void
	223	input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
	224	{
	225	Authctxt *authctxt = ctxt;
	226	Gssctxt *gssctxt;
	227	int authenticated;
	228
	229	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	230	fatal("No authentication or GSSAPI context");
	231
	232	gssctxt = authctxt->methoddata;
	233
	234	/*
0789992b	235	* We don't need to check the status, because we're only enabled in
0789992b	236	* the dispatcher once the exchange is complete
7364bd04	237	*/
	238
	239	packet_check_eom();
	240
	241	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	242
	243	authctxt->postponed = 0;
	244	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	245	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
0789992b	246	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
	247	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
	248	userauth_finish(authctxt, authenticated, "gssapi-with-mic");
	249	}
	250
	251	static void
	252	input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
	253	{
	254	Authctxt *authctxt = ctxt;
	255	Gssctxt *gssctxt;
	256	int authenticated = 0;
	257	Buffer b;
	258	gss_buffer_desc mic, gssbuf;
	259	u_int len;
b6453d99	260
0789992b	261	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
0789992b	262	fatal("No authentication or GSSAPI context");
b6453d99	263
0789992b	264	gssctxt = authctxt->methoddata;
b6453d99	265
0789992b	266	mic.value = packet_get_string(&len);
0789992b	267	mic.length = len;
b6453d99	268
0789992b	269	ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
0789992b	270	"gssapi-with-mic");
b6453d99	271
0789992b	272	gssbuf.value = buffer_ptr(&b);
0789992b	273	gssbuf.length = buffer_len(&b);
b6453d99	274
0789992b	275	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
	276	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	277	else
	278	logit("GSSAPI MIC check failed");
	279
	280	buffer_free(&b);
	281	xfree(mic.value);
b6453d99	282
0789992b	283	authctxt->postponed = 0;
	284	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	285	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
	286	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
7364bd04	287	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
0789992b	288	userauth_finish(authctxt, authenticated, "gssapi-with-mic");
7364bd04	289	}
	290
	291	Authmethod method_gssapi = {
0789992b	292	"gssapi-with-mic",
7364bd04	293	userauth_gssapi,
	294	&options.gss_authentication
	295	};