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

/*	$OpenBSD: auth2-gss.c,v 1.10 2005/07/17 07:17:54 djm 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 ssh_gssapi_userauth_error(Gssctxt *ctxt);
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 *);

static int gssapi_with_mic = 1;	/* flag to toggle "gssapi-with-mic" vs.
				   "gssapi" */

static int
userauth_external(Authctxt *authctxt)
{
        packet_check_eom();

	if (authctxt->valid && authctxt->user && authctxt->user[0]) {
		return(PRIVSEP(ssh_gssapi_userok(authctxt->user)));
	}
	return 0;
}

/* 
 * The 'gssapi_keyex' userauth mechanism.
 */
static int
userauth_gsskeyex(Authctxt *authctxt)
{
	int authenticated = 0;
	Buffer b, b2;
	gss_buffer_desc mic, gssbuf, gssbuf2;
	u_int len;

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

	packet_check_eom();

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

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

	/* client may have used empty username to determine target
	   name from GSSAPI context */
	ssh_gssapi_buildmic(&b2, "", authctxt->service, "gssapi-keyex");

	gssbuf2.value = buffer_ptr(&b2);
	gssbuf2.length = buffer_len(&b2);

	/* gss_kex_context is NULL with privsep, so we can't check it here */
	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context, 
						   &gssbuf, &mic))) ||
	    !GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context, 
						   &gssbuf2, &mic)))) {
	    if (authctxt->valid && authctxt->user && authctxt->user[0]) {
		authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	    }
	}
	
	buffer_free(&b);
	buffer_free(&b2);
	xfree(mic.value);

	return (authenticated);
}

/*
 * 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;

	/* authctxt->valid may be 0 if we haven't yet determined
	   username from gssapi context. */

	if (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);
		authctxt->server_caused_failure = 1;
		return (0);
	}

	if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
		xfree(doid);
		authctxt->server_caused_failure = 1;
		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=0;
	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)) {
        	ssh_gssapi_userauth_error(gssctxt);
		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 ? "gssapi-with-mic" :
				                  "gssapi");
	} 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 && gssapi_with_mic)
				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);
}

static void
gssapi_set_implicit_username(Authctxt *authctxt)
{
    if ((authctxt->user == NULL) || (authctxt->user[0] == '\0')) {
	char *lname = NULL;
	PRIVSEP(ssh_gssapi_localname(&lname));
	if (lname && lname[0] != '\0') {
	    if (authctxt->user) xfree(authctxt->user);
	    authctxt->user = lname;
	    debug("set username to %s from gssapi context", lname);
	    authctxt->pw = PRIVSEP(getpwnamallow(authctxt->user));
	    if (authctxt->pw) {
		authctxt->valid = 1;
	    }
	} else {
	    debug("failed to set username from gssapi context");
	}
    }
    if (authctxt->pw) {
#ifdef USE_PAM
	if (options.use_pam)
		PRIVSEP(start_pam(authctxt));
#endif
    }
}

/*
 * 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");

	gssapi_set_implicit_username(authctxt);

	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();

	/* user should be set if valid but we double-check here */
	if (authctxt->valid && authctxt->user && authctxt->user[0]) {
	    authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	} else {
	    authenticated = 0;
	}

	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 ? "gssapi-with-mic" : "gssapi");
}

static int
userauth_gssapi_with_mic(Authctxt *authctxt)
{
    gssapi_with_mic = 1;
    return userauth_gssapi(authctxt);
}

static int
userauth_gssapi_without_mic(Authctxt *authctxt)
{
    gssapi_with_mic = 0;
    return userauth_gssapi(authctxt);
}

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");

	gssapi_set_implicit_username(authctxt);

	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))))
	    if (authctxt->valid && authctxt->user && authctxt->user[0]) {
		authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	    } else {
		authenticated = 0;
	    }
	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");
}

static void ssh_gssapi_userauth_error(Gssctxt *ctxt) {
	char *errstr;
	OM_uint32 maj,min;
	
	errstr=PRIVSEP(ssh_gssapi_last_error(ctxt,&maj,&min));
	if (errstr) {
		packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERROR);
		packet_put_int(maj);
		packet_put_int(min);
		packet_put_cstring(errstr);
		packet_put_cstring("");
		packet_send();
		packet_write_wait();
		xfree(errstr);
	}
}

Authmethod method_external = {
	"external-keyx",
	userauth_external,
	&options.gss_authentication
};
	
Authmethod method_gsskeyex = {
	"gssapi-keyex",
	userauth_gsskeyex,
	&options.gss_authentication
};

Authmethod method_gssapi = {
	"gssapi-with-mic",
	userauth_gssapi_with_mic,
	&options.gss_authentication
};

Authmethod method_gssapi_compat = {
	"gssapi",
	userauth_gssapi_without_mic,
	&options.gss_authentication
};

#endif /* GSSAPI */
Commit	Line	Data
34fee935	1	/* $OpenBSD: auth2-gss.c,v 1.10 2005/07/17 07:17:54 djm Exp $ */
70791e56	2
ff2d7a98	3	/*
88928908	4	* Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
ff2d7a98	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
70791e56	30
ff2d7a98	31	#include "auth.h"
ff2d7a98	32	#include "ssh2.h"
ff2d7a98	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;
ff2d7a98	44
88928908	45	static void ssh_gssapi_userauth_error(Gssctxt *ctxt);
ff2d7a98	46	static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
416fd2a8	47	static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt);
ff2d7a98	48	static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
88928908	49	static void input_gssapi_errtok(int, u_int32_t, void *);
ff2d7a98	50
416fd2a8	51	static int gssapi_with_mic = 1; /* flag to toggle "gssapi-with-mic" vs.
	52	"gssapi" */
	53
57877bbc	54	static int
	55	userauth_external(Authctxt *authctxt)
	56	{
	57	packet_check_eom();
	58
1b56ff3d	59	if (authctxt->valid && authctxt->user && authctxt->user[0]) {
1b56ff3d	60	return(PRIVSEP(ssh_gssapi_userok(authctxt->user)));
57877bbc	61	}
	62	return 0;
	63	}
	64
34fee935	65	/*
	66	* The 'gssapi_keyex' userauth mechanism.
	67	*/
	68	static int
	69	userauth_gsskeyex(Authctxt *authctxt)
	70	{
	71	int authenticated = 0;
	72	Buffer b, b2;
	73	gss_buffer_desc mic, gssbuf, gssbuf2;
	74	u_int len;
	75
	76	mic.value = packet_get_string(&len);
	77	mic.length = len;
	78
	79	packet_check_eom();
	80
	81	ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
	82	"gssapi-keyex");
	83
	84	gssbuf.value = buffer_ptr(&b);
	85	gssbuf.length = buffer_len(&b);
	86
	87	/* client may have used empty username to determine target
	88	name from GSSAPI context */
	89	ssh_gssapi_buildmic(&b2, "", authctxt->service, "gssapi-keyex");
	90
	91	gssbuf2.value = buffer_ptr(&b2);
	92	gssbuf2.length = buffer_len(&b2);
	93
	94	/* gss_kex_context is NULL with privsep, so we can't check it here */
	95	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context,
	96	&gssbuf, &mic))) \|\|
	97	!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context,
	98	&gssbuf2, &mic)))) {
	99	if (authctxt->valid && authctxt->user && authctxt->user[0]) {
	100	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	101	}
	102	}
	103
	104	buffer_free(&b);
	105	buffer_free(&b2);
	106	xfree(mic.value);
	107
	108	return (authenticated);
	109	}
	110
70791e56	111	/*
70791e56	112	* We only support those mechanisms that we know about (ie ones that we know
ff2d7a98	113	* how to check local user kuserok and the like
	114	*/
	115	static int
	116	userauth_gssapi(Authctxt *authctxt)
	117	{
1b56ff3d	118	gss_OID_desc goid = {0, NULL};
70791e56	119	Gssctxt *ctxt = NULL;
	120	int mechs;
	121	gss_OID_set supported;
	122	int present;
	123	OM_uint32 ms;
	124	u_int len;
34fee935	125	u_char *doid = NULL;
70791e56	126
1b56ff3d	127	/* authctxt->valid may be 0 if we haven't yet determined
	128	username from gssapi context. */
	129
57877bbc	130	if (authctxt->user == NULL)
70791e56	131	return (0);
	132
	133	mechs = packet_get_int();
	134	if (mechs == 0) {
	135	debug("Mechanism negotiation is not supported");
	136	return (0);
88928908	137	}
ff2d7a98	138
70791e56	139	ssh_gssapi_supported_oids(&supported);
	140	do {
	141	mechs--;
ff2d7a98	142
70791e56	143	if (doid)
70791e56	144	xfree(doid);
88928908	145
416fd2a8	146	present = 0;
70791e56	147	doid = packet_get_string(&len);
88928908	148
34fee935	149	if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
34fee935	150	doid[1] == len - 2) {
1b56ff3d	151	goid.elements = doid + 2;
1b56ff3d	152	goid.length = len - 2;
34fee935	153	gss_test_oid_set_member(&ms, &goid, supported,
	154	&present);
	155	} else {
	156	logit("Badly formed OID received");
70791e56	157	}
70791e56	158	} while (mechs > 0 && !present);
	159
	160	gss_release_oid_set(&ms, &supported);
	161
	162	if (!present) {
	163	xfree(doid);
34fee935	164	authctxt->server_caused_failure = 1;
70791e56	165	return (0);
	166	}
	167
1b56ff3d	168	if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
70791e56	169	xfree(doid);
34fee935	170	authctxt->server_caused_failure = 1;
70791e56	171	return (0);
	172	}
	173
	174	authctxt->methoddata=(void *)ctxt;
	175
	176	packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
	177
416fd2a8	178	/* Return the OID that we received */
70791e56	179	packet_put_string(doid, len);
88928908	180
70791e56	181	packet_send();
	182	xfree(doid);
	183
	184	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
	185	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
	186	authctxt->postponed = 1;
	187
	188	return (0);
ff2d7a98	189	}
	190
	191	static void
	192	input_gssapi_token(int type, u_int32_t plen, void *ctxt)
	193	{
70791e56	194	Authctxt *authctxt = ctxt;
	195	Gssctxt *gssctxt;
	196	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	197	gss_buffer_desc recv_tok;
2a304a95	198	OM_uint32 maj_status, min_status, flags=0;
70791e56	199	u_int len;
	200
	201	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	202	fatal("No authentication or GSSAPI context");
	203
	204	gssctxt = authctxt->methoddata;
	205	recv_tok.value = packet_get_string(&len);
	206	recv_tok.length = len; /* u_int vs. size_t */
	207
	208	packet_check_eom();
	209
	210	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
416fd2a8	211	&send_tok, &flags));
70791e56	212
	213	xfree(recv_tok.value);
	214
	215	if (GSS_ERROR(maj_status)) {
88928908	216	ssh_gssapi_userauth_error(gssctxt);
88928908	217	if (send_tok.length != 0) {
88928908	218	packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
70791e56	219	packet_put_string(send_tok.value, send_tok.length);
	220	packet_send();
	221	}
	222	authctxt->postponed = 0;
	223	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
416fd2a8	224	userauth_finish(authctxt, 0,
	225	gssapi_with_mic ? "gssapi-with-mic" :
	226	"gssapi");
70791e56	227	} else {
	228	if (send_tok.length != 0) {
	229	packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
	230	packet_put_string(send_tok.value, send_tok.length);
	231	packet_send();
	232	}
	233	if (maj_status == GSS_S_COMPLETE) {
	234	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
416fd2a8	235	if (flags & GSS_C_INTEG_FLAG && gssapi_with_mic)
	236	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
	237	&input_gssapi_mic);
	238	else
	239	dispatch_set(
	240	SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
	241	&input_gssapi_exchange_complete);
70791e56	242	}
	243	}
	244
	245	gss_release_buffer(&min_status, &send_tok);
88928908	246	}
	247
	248	static void
	249	input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
	250	{
70791e56	251	Authctxt *authctxt = ctxt;
	252	Gssctxt *gssctxt;
	253	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	254	gss_buffer_desc recv_tok;
	255	OM_uint32 maj_status;
	256	u_int len;
	257
	258	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	259	fatal("No authentication or GSSAPI context");
	260
	261	gssctxt = authctxt->methoddata;
	262	recv_tok.value = packet_get_string(&len);
	263	recv_tok.length = len;
	264
	265	packet_check_eom();
	266
	267	/* Push the error token into GSSAPI to see what it says */
	268	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
	269	&send_tok, NULL));
	270
	271	xfree(recv_tok.value);
88928908	272
88928908	273	/* We can't return anything to the client, even if we wanted to */
88928908	274	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
70791e56	275	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
88928908	276
88928908	277	/* The client will have already moved on to the next auth */
70791e56	278
70791e56	279	gss_release_buffer(&maj_status, &send_tok);
ff2d7a98	280	}
ff2d7a98	281
416fd2a8	282	static void
	283	gssapi_set_implicit_username(Authctxt *authctxt)
	284	{
1b56ff3d	285	if ((authctxt->user == NULL) \|\| (authctxt->user[0] == '\0')) {
416fd2a8	286	char *lname = NULL;
	287	PRIVSEP(ssh_gssapi_localname(&lname));
	288	if (lname && lname[0] != '\0') {
1b56ff3d	289	if (authctxt->user) xfree(authctxt->user);
416fd2a8	290	authctxt->user = lname;
	291	debug("set username to %s from gssapi context", lname);
	292	authctxt->pw = PRIVSEP(getpwnamallow(authctxt->user));
57877bbc	293	if (authctxt->pw) {
	294	authctxt->valid = 1;
	295	}
416fd2a8	296	} else {
	297	debug("failed to set username from gssapi context");
	298	}
	299	}
	300	if (authctxt->pw) {
	301	#ifdef USE_PAM
2a304a95	302	if (options.use_pam)
57877bbc	303	PRIVSEP(start_pam(authctxt));
416fd2a8	304	#endif
	305	}
	306	}
	307
70791e56	308	/*
70791e56	309	* This is called when the client thinks we've completed authentication.
ff2d7a98	310	* It should only be enabled in the dispatch handler by the function above,
	311	* which only enables it once the GSSAPI exchange is complete.
	312	*/
70791e56	313
ff2d7a98	314	static void
	315	input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
	316	{
70791e56	317	Authctxt *authctxt = ctxt;
	318	Gssctxt *gssctxt;
	319	int authenticated;
	320
ff2d7a98	321	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
70791e56	322	fatal("No authentication or GSSAPI context");
70791e56	323
416fd2a8	324	gssapi_set_implicit_username(authctxt);
c2397a66	325
70791e56	326	gssctxt = authctxt->methoddata;
ff2d7a98	327
70791e56	328	/*
416fd2a8	329	* We don't need to check the status, because we're only enabled in
416fd2a8	330	* the dispatcher once the exchange is complete
ff2d7a98	331	*/
ff2d7a98	332
70791e56	333	packet_check_eom();
70791e56	334
1b56ff3d	335	/* user should be set if valid but we double-check here */
1b56ff3d	336	if (authctxt->valid && authctxt->user && authctxt->user[0]) {
416fd2a8	337	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	338	} else {
	339	authenticated = 0;
	340	}
ff2d7a98	341
70791e56	342	authctxt->postponed = 0;
	343	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	344	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
416fd2a8	345	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
70791e56	346	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
416fd2a8	347	userauth_finish(authctxt, authenticated,
	348	gssapi_with_mic ? "gssapi-with-mic" : "gssapi");
	349	}
	350
	351	static int
	352	userauth_gssapi_with_mic(Authctxt *authctxt)
	353	{
	354	gssapi_with_mic = 1;
	355	return userauth_gssapi(authctxt);
	356	}
	357
	358	static int
	359	userauth_gssapi_without_mic(Authctxt *authctxt)
	360	{
	361	gssapi_with_mic = 0;
	362	return userauth_gssapi(authctxt);
	363	}
	364
	365	static void
	366	input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
	367	{
	368	Authctxt *authctxt = ctxt;
	369	Gssctxt *gssctxt;
	370	int authenticated = 0;
	371	Buffer b;
	372	gss_buffer_desc mic, gssbuf;
	373	u_int len;
	374
	375	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	376	fatal("No authentication or GSSAPI context");
	377
	378	gssapi_set_implicit_username(authctxt);
	379
	380	gssctxt = authctxt->methoddata;
	381
	382	mic.value = packet_get_string(&len);
	383	mic.length = len;
	384
	385	ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
	386	"gssapi-with-mic");
	387
	388	gssbuf.value = buffer_ptr(&b);
	389	gssbuf.length = buffer_len(&b);
	390
	391	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
1b56ff3d	392	if (authctxt->valid && authctxt->user && authctxt->user[0]) {
416fd2a8	393	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	394	} else {
	395	authenticated = 0;
	396	}
	397	else
	398	logit("GSSAPI MIC check failed");
	399
	400	buffer_free(&b);
	401	xfree(mic.value);
	402
	403	authctxt->postponed = 0;
	404	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	405	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
	406	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
	407	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
	408	userauth_finish(authctxt, authenticated, "gssapi-with-mic");
ff2d7a98	409	}
ff2d7a98	410
88928908	411	static void ssh_gssapi_userauth_error(Gssctxt *ctxt) {
	412	char *errstr;
	413	OM_uint32 maj,min;
	414
	415	errstr=PRIVSEP(ssh_gssapi_last_error(ctxt,&maj,&min));
	416	if (errstr) {
88928908	417	packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERROR);
	418	packet_put_int(maj);
	419	packet_put_int(min);
	420	packet_put_cstring(errstr);
	421	packet_put_cstring("");
	422	packet_send();
	423	packet_write_wait();
	424	xfree(errstr);
88928908	425	}
	426	}
	427
ff2d7a98	428	Authmethod method_external = {
	429	"external-keyx",
	430	userauth_external,
	431	&options.gss_authentication
	432	};
	433
34fee935	434	Authmethod method_gsskeyex = {
	435	"gssapi-keyex",
	436	userauth_gsskeyex,
	437	&options.gss_authentication
	438	};
	439
ff2d7a98	440	Authmethod method_gssapi = {
416fd2a8	441	"gssapi-with-mic",
	442	userauth_gssapi_with_mic,
	443	&options.gss_authentication
	444	};
	445
	446	Authmethod method_gssapi_compat = {
70791e56	447	"gssapi",
416fd2a8	448	userauth_gssapi_without_mic,
70791e56	449	&options.gss_authentication
ff2d7a98	450	};
	451
	452	#endif /* GSSAPI */