[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;
}

/*
 * 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);
		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=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_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
2ce0bfe4	1	/* $OpenBSD: auth2-gss.c,v 1.10 2005/07/17 07:17:54 djm Exp $ */
7cac2b65	2
b59afbfe	3	/*
23987cb8	4	* Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
b59afbfe	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
7cac2b65	30
b59afbfe	31	#include "auth.h"
b59afbfe	32	#include "ssh2.h"
b59afbfe	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;
b59afbfe	44
23987cb8	45	static void ssh_gssapi_userauth_error(Gssctxt *ctxt);
b59afbfe	46	static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
540d72c3	47	static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt);
b59afbfe	48	static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
e23e524c	49	static void input_gssapi_errtok(int, u_int32_t, void *);
b59afbfe	50
540d72c3	51	static int gssapi_with_mic = 1; /* flag to toggle "gssapi-with-mic" vs.
	52	"gssapi" */
	53
5217e987	54	static int
	55	userauth_external(Authctxt *authctxt)
	56	{
	57	packet_check_eom();
	58
7a8e5702	59	if (authctxt->valid && authctxt->user && authctxt->user[0]) {
294206af	60	return(PRIVSEP(ssh_gssapi_userok(authctxt->user)));
5217e987	61	}
	62	return 0;
	63	}
	64
7cac2b65	65	/*
7cac2b65	66	* We only support those mechanisms that we know about (ie ones that we know
b59afbfe	67	* how to check local user kuserok and the like
	68	*/
	69	static int
	70	userauth_gssapi(Authctxt *authctxt)
	71	{
7e82606e	72	gss_OID_desc goid = {0, NULL};
7cac2b65	73	Gssctxt *ctxt = NULL;
	74	int mechs;
	75	gss_OID_set supported;
	76	int present;
	77	OM_uint32 ms;
	78	u_int len;
2ce0bfe4	79	u_char *doid = NULL;
7cac2b65	80
941f3f29	81	/* authctxt->valid may be 0 if we haven't yet determined
	82	username from gssapi context. */
	83
5217e987	84	if (authctxt->user == NULL)
7cac2b65	85	return (0);
	86
	87	mechs = packet_get_int();
	88	if (mechs == 0) {
	89	debug("Mechanism negotiation is not supported");
	90	return (0);
	91	}
	92
	93	ssh_gssapi_supported_oids(&supported);
	94	do {
	95	mechs--;
	96
	97	if (doid)
	98	xfree(doid);
	99
540d72c3	100	present = 0;
7cac2b65	101	doid = packet_get_string(&len);
7cac2b65	102
2ce0bfe4	103	if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
2ce0bfe4	104	doid[1] == len - 2) {
7e82606e	105	goid.elements = doid + 2;
7e82606e	106	goid.length = len - 2;
6fc2ad02	107	gss_test_oid_set_member(&ms, &goid, supported,
	108	&present);
	109	} else {
	110	logit("Badly formed OID received");
7cac2b65	111	}
7cac2b65	112	} while (mechs > 0 && !present);
	113
	114	gss_release_oid_set(&ms, &supported);
	115
	116	if (!present) {
	117	xfree(doid);
	118	return (0);
	119	}
	120
7e82606e	121	if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
7cac2b65	122	xfree(doid);
7cac2b65	123	return (0);
23987cb8	124	}
b59afbfe	125
7cac2b65	126	authctxt->methoddata=(void *)ctxt;
b59afbfe	127
7cac2b65	128	packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
23987cb8	129
540d72c3	130	/* Return the OID that we received */
7cac2b65	131	packet_put_string(doid, len);
23987cb8	132
7cac2b65	133	packet_send();
7cac2b65	134	xfree(doid);
b59afbfe	135
7cac2b65	136	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
	137	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
	138	authctxt->postponed = 1;
	139
	140	return (0);
b59afbfe	141	}
	142
	143	static void
	144	input_gssapi_token(int type, u_int32_t plen, void *ctxt)
	145	{
7cac2b65	146	Authctxt *authctxt = ctxt;
	147	Gssctxt *gssctxt;
	148	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	149	gss_buffer_desc recv_tok;
147c00cc	150	OM_uint32 maj_status, min_status, flags=0;
7cac2b65	151	u_int len;
	152
	153	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	154	fatal("No authentication or GSSAPI context");
	155
	156	gssctxt = authctxt->methoddata;
	157	recv_tok.value = packet_get_string(&len);
	158	recv_tok.length = len; /* u_int vs. size_t */
	159
	160	packet_check_eom();
	161
	162	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
540d72c3	163	&send_tok, &flags));
7cac2b65	164
	165	xfree(recv_tok.value);
	166
	167	if (GSS_ERROR(maj_status)) {
e23e524c	168	ssh_gssapi_userauth_error(gssctxt);
e23e524c	169	if (send_tok.length != 0) {
e23e524c	170	packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
7cac2b65	171	packet_put_string(send_tok.value, send_tok.length);
	172	packet_send();
	173	}
	174	authctxt->postponed = 0;
7cac2b65	175	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
540d72c3	176	userauth_finish(authctxt, 0,
	177	gssapi_with_mic ? "gssapi-with-mic" :
	178	"gssapi");
7cac2b65	179	} else {
7cac2b65	180	if (send_tok.length != 0) {
7cac2b65	181	packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
	182	packet_put_string(send_tok.value, send_tok.length);
	183	packet_send();
	184	}
	185	if (maj_status == GSS_S_COMPLETE) {
7cac2b65	186	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
540d72c3	187	if (flags & GSS_C_INTEG_FLAG && gssapi_with_mic)
	188	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
	189	&input_gssapi_mic);
	190	else
	191	dispatch_set(
	192	SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
	193	&input_gssapi_exchange_complete);
7cac2b65	194	}
	195	}
	196
	197	gss_release_buffer(&min_status, &send_tok);
e23e524c	198	}
23987cb8	199
e23e524c	200	static void
	201	input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
	202	{
7cac2b65	203	Authctxt *authctxt = ctxt;
	204	Gssctxt *gssctxt;
	205	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	206	gss_buffer_desc recv_tok;
	207	OM_uint32 maj_status;
	208	u_int len;
	209
	210	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	211	fatal("No authentication or GSSAPI context");
	212
	213	gssctxt = authctxt->methoddata;
	214	recv_tok.value = packet_get_string(&len);
	215	recv_tok.length = len;
	216
	217	packet_check_eom();
	218
	219	/* Push the error token into GSSAPI to see what it says */
	220	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
	221	&send_tok, NULL));
	222
	223	xfree(recv_tok.value);
e23e524c	224
e23e524c	225	/* We can't return anything to the client, even if we wanted to */
e23e524c	226	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
7cac2b65	227	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
e23e524c	228
e23e524c	229	/* The client will have already moved on to the next auth */
7cac2b65	230
7cac2b65	231	gss_release_buffer(&maj_status, &send_tok);
b59afbfe	232	}
b59afbfe	233
540d72c3	234	static void
	235	gssapi_set_implicit_username(Authctxt *authctxt)
	236	{
4f1e213f	237	if ((authctxt->user == NULL) \|\| (authctxt->user[0] == '\0')) {
540d72c3	238	char *lname = NULL;
	239	PRIVSEP(ssh_gssapi_localname(&lname));
	240	if (lname && lname[0] != '\0') {
4f1e213f	241	if (authctxt->user) xfree(authctxt->user);
540d72c3	242	authctxt->user = lname;
	243	debug("set username to %s from gssapi context", lname);
	244	authctxt->pw = PRIVSEP(getpwnamallow(authctxt->user));
5217e987	245	if (authctxt->pw) {
	246	authctxt->valid = 1;
	247	}
540d72c3	248	} else {
	249	debug("failed to set username from gssapi context");
	250	}
	251	}
	252	if (authctxt->pw) {
	253	#ifdef USE_PAM
147c00cc	254	if (options.use_pam)
5217e987	255	PRIVSEP(start_pam(authctxt));
540d72c3	256	#endif
	257	}
	258	}
	259
7cac2b65	260	/*
7cac2b65	261	* This is called when the client thinks we've completed authentication.
b59afbfe	262	* It should only be enabled in the dispatch handler by the function above,
	263	* which only enables it once the GSSAPI exchange is complete.
	264	*/
7cac2b65	265
b59afbfe	266	static void
	267	input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
	268	{
7cac2b65	269	Authctxt *authctxt = ctxt;
	270	Gssctxt *gssctxt;
	271	int authenticated;
	272
b59afbfe	273	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
7cac2b65	274	fatal("No authentication or GSSAPI context");
7cac2b65	275
540d72c3	276	gssapi_set_implicit_username(authctxt);
d13dfff4	277
7cac2b65	278	gssctxt = authctxt->methoddata;
7cac2b65	279
7cac2b65	280	/*
540d72c3	281	* We don't need to check the status, because we're only enabled in
540d72c3	282	* the dispatcher once the exchange is complete
b59afbfe	283	*/
b59afbfe	284
7cac2b65	285	packet_check_eom();
7cac2b65	286
941f3f29	287	/* user should be set if valid but we double-check here */
941f3f29	288	if (authctxt->valid && authctxt->user && authctxt->user[0]) {
540d72c3	289	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	290	} else {
	291	authenticated = 0;
	292	}
b59afbfe	293
7cac2b65	294	authctxt->postponed = 0;
	295	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	296	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
540d72c3	297	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
7cac2b65	298	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
540d72c3	299	userauth_finish(authctxt, authenticated,
	300	gssapi_with_mic ? "gssapi-with-mic" : "gssapi");
	301	}
	302
	303	static int
	304	userauth_gssapi_with_mic(Authctxt *authctxt)
	305	{
	306	gssapi_with_mic = 1;
	307	return userauth_gssapi(authctxt);
	308	}
	309
	310	static int
	311	userauth_gssapi_without_mic(Authctxt *authctxt)
	312	{
	313	gssapi_with_mic = 0;
	314	return userauth_gssapi(authctxt);
	315	}
	316
	317	static void
	318	input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
	319	{
	320	Authctxt *authctxt = ctxt;
	321	Gssctxt *gssctxt;
	322	int authenticated = 0;
	323	Buffer b;
	324	gss_buffer_desc mic, gssbuf;
	325	u_int len;
	326
	327	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	328	fatal("No authentication or GSSAPI context");
	329
	330	gssapi_set_implicit_username(authctxt);
	331
	332	gssctxt = authctxt->methoddata;
	333
	334	mic.value = packet_get_string(&len);
	335	mic.length = len;
	336
	337	ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
	338	"gssapi-with-mic");
	339
	340	gssbuf.value = buffer_ptr(&b);
	341	gssbuf.length = buffer_len(&b);
	342
	343	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
941f3f29	344	if (authctxt->valid && authctxt->user && authctxt->user[0]) {
540d72c3	345	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	346	} else {
	347	authenticated = 0;
	348	}
	349	else
	350	logit("GSSAPI MIC check failed");
	351
	352	buffer_free(&b);
	353	xfree(mic.value);
	354
	355	authctxt->postponed = 0;
	356	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	357	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
	358	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
	359	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
	360	userauth_finish(authctxt, authenticated, "gssapi-with-mic");
b59afbfe	361	}
b59afbfe	362
23987cb8	363	static void ssh_gssapi_userauth_error(Gssctxt *ctxt) {
	364	char *errstr;
	365	OM_uint32 maj,min;
	366
	367	errstr=PRIVSEP(ssh_gssapi_last_error(ctxt,&maj,&min));
	368	if (errstr) {
	369	packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERROR);
	370	packet_put_int(maj);
	371	packet_put_int(min);
	372	packet_put_cstring(errstr);
	373	packet_put_cstring("");
	374	packet_send();
	375	packet_write_wait();
	376	xfree(errstr);
	377	}
	378	}
	379
b59afbfe	380	Authmethod method_external = {
	381	"external-keyx",
	382	userauth_external,
	383	&options.gss_authentication
	384	};
	385
	386	Authmethod method_gssapi = {
540d72c3	387	"gssapi-with-mic",
	388	userauth_gssapi_with_mic,
	389	&options.gss_authentication
	390	};
	391
	392	Authmethod method_gssapi_compat = {
7cac2b65	393	"gssapi",
540d72c3	394	userauth_gssapi_without_mic,
7cac2b65	395	&options.gss_authentication
b59afbfe	396	};
	397
	398	#endif /* GSSAPI */