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

/*	$OpenBSD: auth2-gss.c,v 1.8 2004/06/21 17:36:31 avsm 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 "auth.h"
#include "ssh2.h"
#include "xmalloc.h"
#include "log.h"
#include "dispatch.h"
#include "servconf.h"
#include "compat.h"
#include "packet.h"
#include "monitor_wrap.h"

#include "ssh-gss.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;
	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)))) {
		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
c9f39d2c	1	/* $OpenBSD: auth2-gss.c,v 1.8 2004/06/21 17:36:31 avsm 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
	31	#include "auth.h"
	32	#include "ssh2.h"
	33	#include "xmalloc.h"
	34	#include "log.h"
	35	#include "dispatch.h"
	36	#include "servconf.h"
	37	#include "compat.h"
	38	#include "packet.h"
	39	#include "monitor_wrap.h"
	40
	41	#include "ssh-gss.h"
	42
	43	extern ServerOptions options;
	44
	45	static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
cdd66111	46	static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt);
0fff78ff	47	static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
	48	static void input_gssapi_errtok(int, u_int32_t, void *);
	49
	50	/*
	51	* We only support those mechanisms that we know about (ie ones that we know
	52	* how to check local user kuserok and the like
	53	*/
	54	static int
	55	userauth_gssapi(Authctxt *authctxt)
	56	{
c9f39d2c	57	gss_OID_desc goid = {0, NULL};
0fff78ff	58	Gssctxt *ctxt = NULL;
	59	int mechs;
	60	gss_OID_set supported;
	61	int present;
	62	OM_uint32 ms;
	63	u_int len;
	64	char *doid = NULL;
	65
	66	if (!authctxt->valid \|\| authctxt->user == NULL)
	67	return (0);
	68
	69	mechs = packet_get_int();
	70	if (mechs == 0) {
	71	debug("Mechanism negotiation is not supported");
	72	return (0);
	73	}
	74
	75	ssh_gssapi_supported_oids(&supported);
	76	do {
	77	mechs--;
	78
	79	if (doid)
	80	xfree(doid);
	81
cdd66111	82	present = 0;
0fff78ff	83	doid = packet_get_string(&len);
0fff78ff	84
cdd66111	85	if (len > 2 &&
	86	doid[0] == SSH_GSS_OIDTYPE &&
	87	doid[1] == len - 2) {
c9f39d2c	88	goid.elements = doid + 2;
	89	goid.length = len - 2;
	90	gss_test_oid_set_member(&ms, &goid, supported,
cdd66111	91	&present);
	92	} else {
	93	logit("Badly formed OID received");
0fff78ff	94	}
0fff78ff	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
c9f39d2c	104	if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
0fff78ff	105	xfree(doid);
	106	return (0);
	107	}
	108
	109	authctxt->methoddata=(void *)ctxt;
	110
	111	packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
	112
cdd66111	113	/* Return the OID that we received */
0fff78ff	114	packet_put_string(doid, len);
	115
	116	packet_send();
	117	xfree(doid);
	118
	119	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
	120	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
	121	authctxt->postponed = 1;
	122
	123	return (0);
	124	}
	125
	126	static void
	127	input_gssapi_token(int type, u_int32_t plen, void *ctxt)
	128	{
	129	Authctxt *authctxt = ctxt;
	130	Gssctxt *gssctxt;
	131	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	132	gss_buffer_desc recv_tok;
cdd66111	133	OM_uint32 maj_status, min_status, flags;
0fff78ff	134	u_int len;
	135
	136	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	137	fatal("No authentication or GSSAPI context");
	138
	139	gssctxt = authctxt->methoddata;
	140	recv_tok.value = packet_get_string(&len);
	141	recv_tok.length = len; /* u_int vs. size_t */
	142
	143	packet_check_eom();
	144
	145	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
cdd66111	146	&send_tok, &flags));
0fff78ff	147
	148	xfree(recv_tok.value);
	149
	150	if (GSS_ERROR(maj_status)) {
	151	if (send_tok.length != 0) {
	152	packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
	153	packet_put_string(send_tok.value, send_tok.length);
	154	packet_send();
	155	}
	156	authctxt->postponed = 0;
	157	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
cdd66111	158	userauth_finish(authctxt, 0, "gssapi-with-mic");
0fff78ff	159	} else {
	160	if (send_tok.length != 0) {
	161	packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
	162	packet_put_string(send_tok.value, send_tok.length);
	163	packet_send();
	164	}
	165	if (maj_status == GSS_S_COMPLETE) {
	166	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
cdd66111	167	if (flags & GSS_C_INTEG_FLAG)
	168	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
	169	&input_gssapi_mic);
	170	else
	171	dispatch_set(
	172	SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
	173	&input_gssapi_exchange_complete);
0fff78ff	174	}
	175	}
	176
	177	gss_release_buffer(&min_status, &send_tok);
	178	}
	179
	180	static void
	181	input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
	182	{
	183	Authctxt *authctxt = ctxt;
	184	Gssctxt *gssctxt;
	185	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	186	gss_buffer_desc recv_tok;
	187	OM_uint32 maj_status;
	188	u_int len;
	189
	190	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	191	fatal("No authentication or GSSAPI context");
	192
	193	gssctxt = authctxt->methoddata;
	194	recv_tok.value = packet_get_string(&len);
	195	recv_tok.length = len;
	196
	197	packet_check_eom();
	198
	199	/* Push the error token into GSSAPI to see what it says */
	200	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
	201	&send_tok, NULL));
	202
	203	xfree(recv_tok.value);
	204
	205	/* We can't return anything to the client, even if we wanted to */
	206	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	207	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
	208
	209	/* The client will have already moved on to the next auth */
	210
	211	gss_release_buffer(&maj_status, &send_tok);
	212	}
	213
	214	/*
	215	* This is called when the client thinks we've completed authentication.
	216	* It should only be enabled in the dispatch handler by the function above,
	217	* which only enables it once the GSSAPI exchange is complete.
	218	*/
	219
	220	static void
	221	input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
	222	{
	223	Authctxt *authctxt = ctxt;
	224	Gssctxt *gssctxt;
	225	int authenticated;
	226
	227	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	228	fatal("No authentication or GSSAPI context");
	229
	230	gssctxt = authctxt->methoddata;
	231
	232	/*
cdd66111	233	* We don't need to check the status, because we're only enabled in
cdd66111	234	* the dispatcher once the exchange is complete
0fff78ff	235	*/
	236
	237	packet_check_eom();
	238
	239	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	240
	241	authctxt->postponed = 0;
	242	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	243	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
cdd66111	244	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
	245	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
	246	userauth_finish(authctxt, authenticated, "gssapi-with-mic");
	247	}
	248
	249	static void
	250	input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
	251	{
	252	Authctxt *authctxt = ctxt;
	253	Gssctxt *gssctxt;
	254	int authenticated = 0;
	255	Buffer b;
	256	gss_buffer_desc mic, gssbuf;
	257	u_int len;
	258
	259	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	260	fatal("No authentication or GSSAPI context");
	261
	262	gssctxt = authctxt->methoddata;
	263
	264	mic.value = packet_get_string(&len);
	265	mic.length = len;
	266
	267	ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
	268	"gssapi-with-mic");
	269
	270	gssbuf.value = buffer_ptr(&b);
	271	gssbuf.length = buffer_len(&b);
	272
	273	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
	274	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	275	else
	276	logit("GSSAPI MIC check failed");
	277
	278	buffer_free(&b);
	279	xfree(mic.value);
	280
	281	authctxt->postponed = 0;
	282	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	283	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
	284	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
0fff78ff	285	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
cdd66111	286	userauth_finish(authctxt, authenticated, "gssapi-with-mic");
0fff78ff	287	}
	288
	289	Authmethod method_gssapi = {
cdd66111	290	"gssapi-with-mic",
0fff78ff	291	userauth_gssapi,
	292	&options.gss_authentication
	293	};
	294
	295	#endif /* GSSAPI */