[gssapi-openssh.git] / openssh / auth2-gss.c

/* $OpenBSD: auth2-gss.c,v 1.16 2007/10/29 00:52:45 dtucker 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"

#ifdef GSSAPI

#include <sys/types.h>

#include <stdarg.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
};

#endif /* GSSAPI */
Commit	Line	Data
47686178	1	/* $OpenBSD: auth2-gss.c,v 1.16 2007/10/29 00:52:45 dtucker Exp $ */
0fff78ff	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
	29	#ifdef GSSAPI
	30
9108f8d9	31	#include <sys/types.h>
	32
	33	#include <stdarg.h>
	34
	35	#include "xmalloc.h"
	36	#include "key.h"
	37	#include "hostfile.h"
0fff78ff	38	#include "auth.h"
0fff78ff	39	#include "ssh2.h"
0fff78ff	40	#include "log.h"
0fff78ff	41	#include "dispatch.h"
9108f8d9	42	#include "buffer.h"
0fff78ff	43	#include "servconf.h"
0fff78ff	44	#include "packet.h"
0fff78ff	45	#include "ssh-gss.h"
9108f8d9	46	#include "monitor_wrap.h"
0fff78ff	47
	48	extern ServerOptions options;
	49
	50	static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
cdd66111	51	static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt);
0fff78ff	52	static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
	53	static void input_gssapi_errtok(int, u_int32_t, void *);
	54
	55	/*
	56	* We only support those mechanisms that we know about (ie ones that we know
2c06c99b	57	* how to check local user kuserok and the like)
0fff78ff	58	*/
	59	static int
	60	userauth_gssapi(Authctxt *authctxt)
	61	{
c9f39d2c	62	gss_OID_desc goid = {0, NULL};
0fff78ff	63	Gssctxt *ctxt = NULL;
	64	int mechs;
	65	gss_OID_set supported;
	66	int present;
	67	OM_uint32 ms;
	68	u_int len;
665a873d	69	u_char *doid = NULL;
0fff78ff	70
	71	if (!authctxt->valid \|\| authctxt->user == NULL)
	72	return (0);
	73
	74	mechs = packet_get_int();
	75	if (mechs == 0) {
	76	debug("Mechanism negotiation is not supported");
	77	return (0);
	78	}
	79
	80	ssh_gssapi_supported_oids(&supported);
	81	do {
	82	mechs--;
	83
	84	if (doid)
	85	xfree(doid);
	86
cdd66111	87	present = 0;
0fff78ff	88	doid = packet_get_string(&len);
0fff78ff	89
665a873d	90	if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
665a873d	91	doid[1] == len - 2) {
c9f39d2c	92	goid.elements = doid + 2;
	93	goid.length = len - 2;
	94	gss_test_oid_set_member(&ms, &goid, supported,
cdd66111	95	&present);
	96	} else {
	97	logit("Badly formed OID received");
0fff78ff	98	}
0fff78ff	99	} while (mechs > 0 && !present);
	100
	101	gss_release_oid_set(&ms, &supported);
	102
	103	if (!present) {
	104	xfree(doid);
	105	return (0);
	106	}
	107
c9f39d2c	108	if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
9108f8d9	109	if (ctxt != NULL)
9108f8d9	110	ssh_gssapi_delete_ctx(&ctxt);
0fff78ff	111	xfree(doid);
	112	return (0);
	113	}
	114
2c06c99b	115	authctxt->methoddata = (void *)ctxt;
0fff78ff	116
	117	packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
	118
cdd66111	119	/* Return the OID that we received */
0fff78ff	120	packet_put_string(doid, len);
	121
	122	packet_send();
	123	xfree(doid);
	124
	125	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
	126	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
	127	authctxt->postponed = 1;
	128
	129	return (0);
	130	}
	131
	132	static void
	133	input_gssapi_token(int type, u_int32_t plen, void *ctxt)
	134	{
	135	Authctxt *authctxt = ctxt;
	136	Gssctxt *gssctxt;
	137	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	138	gss_buffer_desc recv_tok;
cdd66111	139	OM_uint32 maj_status, min_status, flags;
0fff78ff	140	u_int len;
	141
	142	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	143	fatal("No authentication or GSSAPI context");
	144
	145	gssctxt = authctxt->methoddata;
	146	recv_tok.value = packet_get_string(&len);
	147	recv_tok.length = len; /* u_int vs. size_t */
	148
	149	packet_check_eom();
	150
	151	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
cdd66111	152	&send_tok, &flags));
0fff78ff	153
	154	xfree(recv_tok.value);
	155
	156	if (GSS_ERROR(maj_status)) {
	157	if (send_tok.length != 0) {
	158	packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
	159	packet_put_string(send_tok.value, send_tok.length);
	160	packet_send();
	161	}
	162	authctxt->postponed = 0;
	163	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
cdd66111	164	userauth_finish(authctxt, 0, "gssapi-with-mic");
0fff78ff	165	} else {
	166	if (send_tok.length != 0) {
	167	packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
	168	packet_put_string(send_tok.value, send_tok.length);
	169	packet_send();
	170	}
	171	if (maj_status == GSS_S_COMPLETE) {
	172	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
cdd66111	173	if (flags & GSS_C_INTEG_FLAG)
	174	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
	175	&input_gssapi_mic);
	176	else
	177	dispatch_set(
	178	SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
	179	&input_gssapi_exchange_complete);
0fff78ff	180	}
	181	}
	182
	183	gss_release_buffer(&min_status, &send_tok);
	184	}
	185
	186	static void
	187	input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
	188	{
	189	Authctxt *authctxt = ctxt;
	190	Gssctxt *gssctxt;
	191	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	192	gss_buffer_desc recv_tok;
	193	OM_uint32 maj_status;
	194	u_int len;
	195
	196	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	197	fatal("No authentication or GSSAPI context");
	198
	199	gssctxt = authctxt->methoddata;
	200	recv_tok.value = packet_get_string(&len);
	201	recv_tok.length = len;
	202
	203	packet_check_eom();
	204
	205	/* Push the error token into GSSAPI to see what it says */
	206	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
	207	&send_tok, NULL));
	208
	209	xfree(recv_tok.value);
	210
	211	/* We can't return anything to the client, even if we wanted to */
	212	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	213	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
	214
	215	/* The client will have already moved on to the next auth */
	216
	217	gss_release_buffer(&maj_status, &send_tok);
	218	}
	219
	220	/*
	221	* This is called when the client thinks we've completed authentication.
	222	* It should only be enabled in the dispatch handler by the function above,
	223	* which only enables it once the GSSAPI exchange is complete.
	224	*/
	225
	226	static void
	227	input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
	228	{
	229	Authctxt *authctxt = ctxt;
	230	Gssctxt *gssctxt;
	231	int authenticated;
	232
	233	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	234	fatal("No authentication or GSSAPI context");
	235
	236	gssctxt = authctxt->methoddata;
	237
	238	/*
cdd66111	239	* We don't need to check the status, because we're only enabled in
cdd66111	240	* the dispatcher once the exchange is complete
0fff78ff	241	*/
	242
	243	packet_check_eom();
	244
	245	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	246
	247	authctxt->postponed = 0;
	248	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	249	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
cdd66111	250	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
	251	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
	252	userauth_finish(authctxt, authenticated, "gssapi-with-mic");
	253	}
	254
	255	static void
	256	input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
	257	{
	258	Authctxt *authctxt = ctxt;
	259	Gssctxt *gssctxt;
	260	int authenticated = 0;
	261	Buffer b;
	262	gss_buffer_desc mic, gssbuf;
	263	u_int len;
	264
	265	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	266	fatal("No authentication or GSSAPI context");
	267
	268	gssctxt = authctxt->methoddata;
	269
	270	mic.value = packet_get_string(&len);
	271	mic.length = len;
	272
	273	ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
	274	"gssapi-with-mic");
	275
	276	gssbuf.value = buffer_ptr(&b);
	277	gssbuf.length = buffer_len(&b);
	278
	279	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
	280	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	281	else
	282	logit("GSSAPI MIC check failed");
	283
	284	buffer_free(&b);
	285	xfree(mic.value);
	286
	287	authctxt->postponed = 0;
	288	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	289	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
	290	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
0fff78ff	291	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
cdd66111	292	userauth_finish(authctxt, authenticated, "gssapi-with-mic");
0fff78ff	293	}
	294
	295	Authmethod method_gssapi = {
cdd66111	296	"gssapi-with-mic",
0fff78ff	297	userauth_gssapi,
	298	&options.gss_authentication
	299	};
	300
	301	#endif /* GSSAPI */