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

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

/*
 * Copyright (c) 2001-2007 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 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 *);

/* 
 * 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,
                                                      authctxt->pw,
                                                      1 /* gssapi-keyex */));
	    }
	}
	
	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)))) {
		if (ctxt != NULL)
			ssh_gssapi_delete_ctx(&ctxt);
		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");
	} 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);
}

static void
gssapi_set_username(Authctxt *authctxt)
{
    char *lname = NULL;

    if ((authctxt->user == NULL) || (authctxt->user[0] == '\0')) {
        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;
#ifdef USE_PAM
                if (options.use_pam)
                    PRIVSEP(start_pam(authctxt));
#endif
            }
        } else {
            debug("failed to set username from gssapi context");
            packet_send_debug("failed to set username from gssapi context");
        }
    }
}

/*
 * 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_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,
                                       authctxt->pw, 0 /* !gssapi-keyex */));
	} 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");
}

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);

    gssapi_set_username(authctxt);

	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, authctxt->pw,
                                              0 /* !gssapi-keyex */));
	    } 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_gsskeyex = {
	"gssapi-keyex",
	userauth_gsskeyex,
	&options.gss_authentication
};

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

#endif /* GSSAPI */
Commit	Line	Data
e74dc197	1	/* $OpenBSD: auth2-gss.c,v 1.16 2007/10/29 00:52:45 dtucker Exp $ */
7cac2b65	2
b59afbfe	3	/*
f97edba6	4	* Copyright (c) 2001-2007 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
30460aeb	31	#include <sys/types.h>
	32
	33	#include <stdarg.h>
	34
	35	#include "xmalloc.h"
	36	#include "key.h"
	37	#include "hostfile.h"
b59afbfe	38	#include "auth.h"
b59afbfe	39	#include "ssh2.h"
b59afbfe	40	#include "log.h"
b59afbfe	41	#include "dispatch.h"
30460aeb	42	#include "buffer.h"
b59afbfe	43	#include "servconf.h"
b59afbfe	44	#include "packet.h"
b59afbfe	45	#include "ssh-gss.h"
30460aeb	46	#include "monitor_wrap.h"
b59afbfe	47
b59afbfe	48	extern ServerOptions options;
b59afbfe	49
23987cb8	50	static void ssh_gssapi_userauth_error(Gssctxt *ctxt);
b59afbfe	51	static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
540d72c3	52	static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt);
b59afbfe	53	static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
e23e524c	54	static void input_gssapi_errtok(int, u_int32_t, void *);
b59afbfe	55
fe4ad273	56	/*
	57	* The 'gssapi_keyex' userauth mechanism.
	58	*/
	59	static int
	60	userauth_gsskeyex(Authctxt *authctxt)
	61	{
	62	int authenticated = 0;
	63	Buffer b, b2;
	64	gss_buffer_desc mic, gssbuf, gssbuf2;
	65	u_int len;
	66
	67	mic.value = packet_get_string(&len);
	68	mic.length = len;
	69
	70	packet_check_eom();
	71
	72	ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
	73	"gssapi-keyex");
	74
	75	gssbuf.value = buffer_ptr(&b);
	76	gssbuf.length = buffer_len(&b);
	77
	78	/* client may have used empty username to determine target
	79	name from GSSAPI context */
	80	ssh_gssapi_buildmic(&b2, "", authctxt->service, "gssapi-keyex");
	81
	82	gssbuf2.value = buffer_ptr(&b2);
	83	gssbuf2.length = buffer_len(&b2);
	84
	85	/* gss_kex_context is NULL with privsep, so we can't check it here */
	86	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context,
	87	&gssbuf, &mic))) \|\|
	88	!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context,
	89	&gssbuf2, &mic)))) {
	90	if (authctxt->valid && authctxt->user && authctxt->user[0]) {
c7931c9a	91	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
09dcbb73	92	authctxt->pw,
09dcbb73	93	1 /* gssapi-keyex */));
fe4ad273	94	}
	95	}
	96
	97	buffer_free(&b);
	98	buffer_free(&b2);
	99	xfree(mic.value);
	100
	101	return (authenticated);
	102	}
	103
7cac2b65	104	/*
7cac2b65	105	* We only support those mechanisms that we know about (ie ones that we know
08822d99	106	* how to check local user kuserok and the like)
b59afbfe	107	*/
	108	static int
	109	userauth_gssapi(Authctxt *authctxt)
	110	{
7e82606e	111	gss_OID_desc goid = {0, NULL};
7cac2b65	112	Gssctxt *ctxt = NULL;
	113	int mechs;
	114	gss_OID_set supported;
	115	int present;
	116	OM_uint32 ms;
	117	u_int len;
2ce0bfe4	118	u_char *doid = NULL;
7cac2b65	119
941f3f29	120	/* authctxt->valid may be 0 if we haven't yet determined
	121	username from gssapi context. */
	122
5217e987	123	if (authctxt->user == NULL)
7cac2b65	124	return (0);
	125
	126	mechs = packet_get_int();
	127	if (mechs == 0) {
	128	debug("Mechanism negotiation is not supported");
	129	return (0);
	130	}
	131
	132	ssh_gssapi_supported_oids(&supported);
	133	do {
	134	mechs--;
	135
	136	if (doid)
	137	xfree(doid);
	138
540d72c3	139	present = 0;
7cac2b65	140	doid = packet_get_string(&len);
7cac2b65	141
2ce0bfe4	142	if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
2ce0bfe4	143	doid[1] == len - 2) {
7e82606e	144	goid.elements = doid + 2;
7e82606e	145	goid.length = len - 2;
6fc2ad02	146	gss_test_oid_set_member(&ms, &goid, supported,
	147	&present);
	148	} else {
	149	logit("Badly formed OID received");
7cac2b65	150	}
7cac2b65	151	} while (mechs > 0 && !present);
	152
	153	gss_release_oid_set(&ms, &supported);
	154
	155	if (!present) {
	156	xfree(doid);
fe4ad273	157	authctxt->server_caused_failure = 1;
7cac2b65	158	return (0);
	159	}
	160
7e82606e	161	if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
30460aeb	162	if (ctxt != NULL)
30460aeb	163	ssh_gssapi_delete_ctx(&ctxt);
7cac2b65	164	xfree(doid);
fe4ad273	165	authctxt->server_caused_failure = 1;
7cac2b65	166	return (0);
23987cb8	167	}
b59afbfe	168
08822d99	169	authctxt->methoddata = (void *)ctxt;
b59afbfe	170
7cac2b65	171	packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
23987cb8	172
540d72c3	173	/* Return the OID that we received */
7cac2b65	174	packet_put_string(doid, len);
23987cb8	175
7cac2b65	176	packet_send();
7cac2b65	177	xfree(doid);
b59afbfe	178
7cac2b65	179	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
	180	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
	181	authctxt->postponed = 1;
	182
	183	return (0);
b59afbfe	184	}
	185
	186	static void
	187	input_gssapi_token(int type, u_int32_t plen, void *ctxt)
	188	{
7cac2b65	189	Authctxt *authctxt = ctxt;
	190	Gssctxt *gssctxt;
	191	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	192	gss_buffer_desc recv_tok;
147c00cc	193	OM_uint32 maj_status, min_status, flags=0;
7cac2b65	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; /* u_int vs. size_t */
	202
	203	packet_check_eom();
	204
	205	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
540d72c3	206	&send_tok, &flags));
7cac2b65	207
	208	xfree(recv_tok.value);
	209
	210	if (GSS_ERROR(maj_status)) {
e23e524c	211	ssh_gssapi_userauth_error(gssctxt);
e23e524c	212	if (send_tok.length != 0) {
e23e524c	213	packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
7cac2b65	214	packet_put_string(send_tok.value, send_tok.length);
	215	packet_send();
	216	}
	217	authctxt->postponed = 0;
7cac2b65	218	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
22ce3a3b	219	userauth_finish(authctxt, 0, "gssapi-with-mic");
7cac2b65	220	} else {
7cac2b65	221	if (send_tok.length != 0) {
7cac2b65	222	packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
	223	packet_put_string(send_tok.value, send_tok.length);
	224	packet_send();
	225	}
	226	if (maj_status == GSS_S_COMPLETE) {
7cac2b65	227	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
22ce3a3b	228	if (flags & GSS_C_INTEG_FLAG)
540d72c3	229	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
	230	&input_gssapi_mic);
	231	else
	232	dispatch_set(
	233	SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
	234	&input_gssapi_exchange_complete);
7cac2b65	235	}
	236	}
	237
	238	gss_release_buffer(&min_status, &send_tok);
e23e524c	239	}
23987cb8	240
e23e524c	241	static void
	242	input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
	243	{
7cac2b65	244	Authctxt *authctxt = ctxt;
	245	Gssctxt *gssctxt;
	246	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	247	gss_buffer_desc recv_tok;
	248	OM_uint32 maj_status;
	249	u_int len;
	250
	251	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	252	fatal("No authentication or GSSAPI context");
	253
	254	gssctxt = authctxt->methoddata;
	255	recv_tok.value = packet_get_string(&len);
	256	recv_tok.length = len;
	257
	258	packet_check_eom();
	259
	260	/* Push the error token into GSSAPI to see what it says */
	261	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
	262	&send_tok, NULL));
	263
	264	xfree(recv_tok.value);
e23e524c	265
e23e524c	266	/* We can't return anything to the client, even if we wanted to */
e23e524c	267	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
7cac2b65	268	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
e23e524c	269
e23e524c	270	/* The client will have already moved on to the next auth */
7cac2b65	271
7cac2b65	272	gss_release_buffer(&maj_status, &send_tok);
b59afbfe	273	}
b59afbfe	274
540d72c3	275	static void
86a22a0a	276	gssapi_set_username(Authctxt *authctxt)
540d72c3	277	{
86a22a0a	278	char *lname = NULL;
86a22a0a	279
4f1e213f	280	if ((authctxt->user == NULL) \|\| (authctxt->user[0] == '\0')) {
86a22a0a	281	PRIVSEP(ssh_gssapi_localname(&lname));
	282	if (lname && lname[0] != '\0') {
	283	if (authctxt->user) xfree(authctxt->user);
	284	authctxt->user = lname;
	285	debug("set username to %s from gssapi context", lname);
	286	authctxt->pw = PRIVSEP(getpwnamallow(authctxt->user));
	287	if (authctxt->pw) {
	288	authctxt->valid = 1;
540d72c3	289	#ifdef USE_PAM
86a22a0a	290	if (options.use_pam)
86a22a0a	291	PRIVSEP(start_pam(authctxt));
540d72c3	292	#endif
86a22a0a	293	}
	294	} else {
	295	debug("failed to set username from gssapi context");
	296	packet_send_debug("failed to set username from gssapi context");
	297	}
540d72c3	298	}
	299	}
	300
7cac2b65	301	/*
7cac2b65	302	* This is called when the client thinks we've completed authentication.
b59afbfe	303	* It should only be enabled in the dispatch handler by the function above,
	304	* which only enables it once the GSSAPI exchange is complete.
	305	*/
7cac2b65	306
b59afbfe	307	static void
	308	input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
	309	{
7cac2b65	310	Authctxt *authctxt = ctxt;
	311	Gssctxt *gssctxt;
	312	int authenticated;
	313
b59afbfe	314	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
7cac2b65	315	fatal("No authentication or GSSAPI context");
7cac2b65	316
3ea093c4	317	gssapi_set_username(authctxt);
d13dfff4	318
7cac2b65	319	gssctxt = authctxt->methoddata;
7cac2b65	320
7cac2b65	321	/*
540d72c3	322	* We don't need to check the status, because we're only enabled in
540d72c3	323	* the dispatcher once the exchange is complete
b59afbfe	324	*/
b59afbfe	325
7cac2b65	326	packet_check_eom();
7cac2b65	327
941f3f29	328	/* user should be set if valid but we double-check here */
941f3f29	329	if (authctxt->valid && authctxt->user && authctxt->user[0]) {
c7931c9a	330	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
09dcbb73	331	authctxt->pw, 0 /* !gssapi-keyex */));
540d72c3	332	} else {
	333	authenticated = 0;
	334	}
b59afbfe	335
7cac2b65	336	authctxt->postponed = 0;
	337	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	338	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
540d72c3	339	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
7cac2b65	340	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
22ce3a3b	341	userauth_finish(authctxt, authenticated, "gssapi-with-mic");
540d72c3	342	}
	343
	344	static void
	345	input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
	346	{
	347	Authctxt *authctxt = ctxt;
	348	Gssctxt *gssctxt;
	349	int authenticated = 0;
	350	Buffer b;
	351	gss_buffer_desc mic, gssbuf;
	352	u_int len;
	353
	354	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	355	fatal("No authentication or GSSAPI context");
	356
540d72c3	357	gssctxt = authctxt->methoddata;
	358
	359	mic.value = packet_get_string(&len);
	360	mic.length = len;
	361
	362	ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
	363	"gssapi-with-mic");
	364
	365	gssbuf.value = buffer_ptr(&b);
	366	gssbuf.length = buffer_len(&b);
	367
86a22a0a	368	gssapi_set_username(authctxt);
86a22a0a	369
540d72c3	370	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
941f3f29	371	if (authctxt->valid && authctxt->user && authctxt->user[0]) {
c7931c9a	372	authenticated =
09dcbb73	373	PRIVSEP(ssh_gssapi_userok(authctxt->user, authctxt->pw,
09dcbb73	374	0 /* !gssapi-keyex */));
540d72c3	375	} else {
c7931c9a	376	authenticated = 0;
540d72c3	377	}
	378	else
	379	logit("GSSAPI MIC check failed");
	380
	381	buffer_free(&b);
	382	xfree(mic.value);
	383
	384	authctxt->postponed = 0;
	385	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	386	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
	387	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
	388	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
	389	userauth_finish(authctxt, authenticated, "gssapi-with-mic");
b59afbfe	390	}
b59afbfe	391
23987cb8	392	static void ssh_gssapi_userauth_error(Gssctxt *ctxt) {
	393	char *errstr;
	394	OM_uint32 maj,min;
	395
	396	errstr=PRIVSEP(ssh_gssapi_last_error(ctxt,&maj,&min));
	397	if (errstr) {
	398	packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERROR);
	399	packet_put_int(maj);
	400	packet_put_int(min);
	401	packet_put_cstring(errstr);
	402	packet_put_cstring("");
	403	packet_send();
	404	packet_write_wait();
	405	xfree(errstr);
	406	}
	407	}
	408
fe4ad273	409	Authmethod method_gsskeyex = {
	410	"gssapi-keyex",
	411	userauth_gsskeyex,
	412	&options.gss_authentication
	413	};
	414
b59afbfe	415	Authmethod method_gssapi = {
540d72c3	416	"gssapi-with-mic",
22ce3a3b	417	userauth_gssapi,
7cac2b65	418	&options.gss_authentication
b59afbfe	419	};
	420
	421	#endif /* GSSAPI */