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

/*	$OpenBSD: auth2-gss.c,v 1.12 2005/10/13 22:24:31 stevesk 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 "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;
	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)))) {
		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
2c06c99b	1	/* $OpenBSD: auth2-gss.c,v 1.12 2005/10/13 22:24:31 stevesk 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"
0fff78ff	37	#include "packet.h"
	38	#include "monitor_wrap.h"
	39
	40	#include "ssh-gss.h"
	41
	42	extern ServerOptions options;
	43
	44	static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
cdd66111	45	static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt);
0fff78ff	46	static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
	47	static void input_gssapi_errtok(int, u_int32_t, void *);
	48
	49	/*
	50	* We only support those mechanisms that we know about (ie ones that we know
2c06c99b	51	* how to check local user kuserok and the like)
0fff78ff	52	*/
	53	static int
	54	userauth_gssapi(Authctxt *authctxt)
	55	{
c9f39d2c	56	gss_OID_desc goid = {0, NULL};
0fff78ff	57	Gssctxt *ctxt = NULL;
	58	int mechs;
	59	gss_OID_set supported;
	60	int present;
	61	OM_uint32 ms;
	62	u_int len;
665a873d	63	u_char *doid = NULL;
0fff78ff	64
	65	if (!authctxt->valid \|\| authctxt->user == NULL)
	66	return (0);
	67
	68	mechs = packet_get_int();
	69	if (mechs == 0) {
	70	debug("Mechanism negotiation is not supported");
	71	return (0);
	72	}
	73
	74	ssh_gssapi_supported_oids(&supported);
	75	do {
	76	mechs--;
	77
	78	if (doid)
	79	xfree(doid);
	80
cdd66111	81	present = 0;
0fff78ff	82	doid = packet_get_string(&len);
0fff78ff	83
665a873d	84	if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
665a873d	85	doid[1] == len - 2) {
c9f39d2c	86	goid.elements = doid + 2;
	87	goid.length = len - 2;
	88	gss_test_oid_set_member(&ms, &goid, supported,
cdd66111	89	&present);
	90	} else {
	91	logit("Badly formed OID received");
0fff78ff	92	}
0fff78ff	93	} while (mechs > 0 && !present);
	94
	95	gss_release_oid_set(&ms, &supported);
	96
	97	if (!present) {
	98	xfree(doid);
	99	return (0);
	100	}
	101
c9f39d2c	102	if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
0fff78ff	103	xfree(doid);
	104	return (0);
	105	}
	106
2c06c99b	107	authctxt->methoddata = (void *)ctxt;
0fff78ff	108
	109	packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
	110
cdd66111	111	/* Return the OID that we received */
0fff78ff	112	packet_put_string(doid, len);
	113
	114	packet_send();
	115	xfree(doid);
	116
	117	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
	118	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
	119	authctxt->postponed = 1;
	120
	121	return (0);
	122	}
	123
	124	static void
	125	input_gssapi_token(int type, u_int32_t plen, void *ctxt)
	126	{
	127	Authctxt *authctxt = ctxt;
	128	Gssctxt *gssctxt;
	129	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	130	gss_buffer_desc recv_tok;
cdd66111	131	OM_uint32 maj_status, min_status, flags;
0fff78ff	132	u_int len;
	133
	134	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	135	fatal("No authentication or GSSAPI context");
	136
	137	gssctxt = authctxt->methoddata;
	138	recv_tok.value = packet_get_string(&len);
	139	recv_tok.length = len; /* u_int vs. size_t */
	140
	141	packet_check_eom();
	142
	143	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
cdd66111	144	&send_tok, &flags));
0fff78ff	145
	146	xfree(recv_tok.value);
	147
	148	if (GSS_ERROR(maj_status)) {
	149	if (send_tok.length != 0) {
	150	packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
	151	packet_put_string(send_tok.value, send_tok.length);
	152	packet_send();
	153	}
	154	authctxt->postponed = 0;
	155	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
cdd66111	156	userauth_finish(authctxt, 0, "gssapi-with-mic");
0fff78ff	157	} else {
	158	if (send_tok.length != 0) {
	159	packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
	160	packet_put_string(send_tok.value, send_tok.length);
	161	packet_send();
	162	}
	163	if (maj_status == GSS_S_COMPLETE) {
	164	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
cdd66111	165	if (flags & GSS_C_INTEG_FLAG)
	166	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
	167	&input_gssapi_mic);
	168	else
	169	dispatch_set(
	170	SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
	171	&input_gssapi_exchange_complete);
0fff78ff	172	}
	173	}
	174
	175	gss_release_buffer(&min_status, &send_tok);
	176	}
	177
	178	static void
	179	input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
	180	{
	181	Authctxt *authctxt = ctxt;
	182	Gssctxt *gssctxt;
	183	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	184	gss_buffer_desc recv_tok;
	185	OM_uint32 maj_status;
	186	u_int len;
	187
	188	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	189	fatal("No authentication or GSSAPI context");
	190
	191	gssctxt = authctxt->methoddata;
	192	recv_tok.value = packet_get_string(&len);
	193	recv_tok.length = len;
	194
	195	packet_check_eom();
	196
	197	/* Push the error token into GSSAPI to see what it says */
	198	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
	199	&send_tok, NULL));
	200
	201	xfree(recv_tok.value);
	202
	203	/* We can't return anything to the client, even if we wanted to */
	204	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	205	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
	206
	207	/* The client will have already moved on to the next auth */
	208
	209	gss_release_buffer(&maj_status, &send_tok);
	210	}
	211
	212	/*
	213	* This is called when the client thinks we've completed authentication.
	214	* It should only be enabled in the dispatch handler by the function above,
	215	* which only enables it once the GSSAPI exchange is complete.
	216	*/
	217
	218	static void
	219	input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
	220	{
	221	Authctxt *authctxt = ctxt;
	222	Gssctxt *gssctxt;
	223	int authenticated;
	224
	225	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	226	fatal("No authentication or GSSAPI context");
	227
	228	gssctxt = authctxt->methoddata;
	229
	230	/*
cdd66111	231	* We don't need to check the status, because we're only enabled in
cdd66111	232	* the dispatcher once the exchange is complete
0fff78ff	233	*/
	234
	235	packet_check_eom();
	236
	237	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	238
	239	authctxt->postponed = 0;
	240	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	241	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
cdd66111	242	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
	243	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
	244	userauth_finish(authctxt, authenticated, "gssapi-with-mic");
	245	}
	246
	247	static void
	248	input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
	249	{
	250	Authctxt *authctxt = ctxt;
	251	Gssctxt *gssctxt;
	252	int authenticated = 0;
	253	Buffer b;
	254	gss_buffer_desc mic, gssbuf;
	255	u_int len;
	256
	257	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	258	fatal("No authentication or GSSAPI context");
	259
	260	gssctxt = authctxt->methoddata;
	261
	262	mic.value = packet_get_string(&len);
	263	mic.length = len;
	264
	265	ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
	266	"gssapi-with-mic");
	267
	268	gssbuf.value = buffer_ptr(&b);
	269	gssbuf.length = buffer_len(&b);
	270
	271	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
	272	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	273	else
	274	logit("GSSAPI MIC check failed");
	275
	276	buffer_free(&b);
	277	xfree(mic.value);
	278
	279	authctxt->postponed = 0;
	280	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	281	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
	282	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
0fff78ff	283	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
cdd66111	284	userauth_finish(authctxt, authenticated, "gssapi-with-mic");
0fff78ff	285	}
	286
	287	Authmethod method_gssapi = {
cdd66111	288	"gssapi-with-mic",
0fff78ff	289	userauth_gssapi,
	290	&options.gss_authentication
	291	};
	292
	293	#endif /* GSSAPI */