[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 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");
	    packet_send_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
08822d99	1	/* $OpenBSD: auth2-gss.c,v 1.12 2005/10/13 22:24:31 stevesk 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"
b59afbfe	37	#include "packet.h"
	38	#include "monitor_wrap.h"
	39
	40	#include "ssh-gss.h"
	41
	42	extern ServerOptions options;
b59afbfe	43
23987cb8	44	static void ssh_gssapi_userauth_error(Gssctxt *ctxt);
b59afbfe	45	static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
540d72c3	46	static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt);
b59afbfe	47	static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
e23e524c	48	static void input_gssapi_errtok(int, u_int32_t, void *);
b59afbfe	49
540d72c3	50	static int gssapi_with_mic = 1; /* flag to toggle "gssapi-with-mic" vs.
	51	"gssapi" */
	52
5217e987	53	static int
	54	userauth_external(Authctxt *authctxt)
	55	{
	56	packet_check_eom();
	57
7a8e5702	58	if (authctxt->valid && authctxt->user && authctxt->user[0]) {
294206af	59	return(PRIVSEP(ssh_gssapi_userok(authctxt->user)));
5217e987	60	}
	61	return 0;
	62	}
	63
fe4ad273	64	/*
	65	* The 'gssapi_keyex' userauth mechanism.
	66	*/
	67	static int
	68	userauth_gsskeyex(Authctxt *authctxt)
	69	{
	70	int authenticated = 0;
	71	Buffer b, b2;
	72	gss_buffer_desc mic, gssbuf, gssbuf2;
	73	u_int len;
	74
	75	mic.value = packet_get_string(&len);
	76	mic.length = len;
	77
	78	packet_check_eom();
	79
	80	ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
	81	"gssapi-keyex");
	82
	83	gssbuf.value = buffer_ptr(&b);
	84	gssbuf.length = buffer_len(&b);
	85
	86	/* client may have used empty username to determine target
	87	name from GSSAPI context */
	88	ssh_gssapi_buildmic(&b2, "", authctxt->service, "gssapi-keyex");
	89
	90	gssbuf2.value = buffer_ptr(&b2);
	91	gssbuf2.length = buffer_len(&b2);
	92
	93	/* gss_kex_context is NULL with privsep, so we can't check it here */
	94	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context,
	95	&gssbuf, &mic))) \|\|
	96	!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context,
	97	&gssbuf2, &mic)))) {
	98	if (authctxt->valid && authctxt->user && authctxt->user[0]) {
	99	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	100	}
	101	}
	102
	103	buffer_free(&b);
	104	buffer_free(&b2);
	105	xfree(mic.value);
	106
	107	return (authenticated);
	108	}
	109
7cac2b65	110	/*
7cac2b65	111	* We only support those mechanisms that we know about (ie ones that we know
08822d99	112	* how to check local user kuserok and the like)
b59afbfe	113	*/
	114	static int
	115	userauth_gssapi(Authctxt *authctxt)
	116	{
7e82606e	117	gss_OID_desc goid = {0, NULL};
7cac2b65	118	Gssctxt *ctxt = NULL;
	119	int mechs;
	120	gss_OID_set supported;
	121	int present;
	122	OM_uint32 ms;
	123	u_int len;
2ce0bfe4	124	u_char *doid = NULL;
7cac2b65	125
941f3f29	126	/* authctxt->valid may be 0 if we haven't yet determined
	127	username from gssapi context. */
	128
5217e987	129	if (authctxt->user == NULL)
7cac2b65	130	return (0);
	131
	132	mechs = packet_get_int();
	133	if (mechs == 0) {
	134	debug("Mechanism negotiation is not supported");
	135	return (0);
	136	}
	137
	138	ssh_gssapi_supported_oids(&supported);
	139	do {
	140	mechs--;
	141
	142	if (doid)
	143	xfree(doid);
	144
540d72c3	145	present = 0;
7cac2b65	146	doid = packet_get_string(&len);
7cac2b65	147
2ce0bfe4	148	if (len > 2 && doid[0] == SSH_GSS_OIDTYPE &&
2ce0bfe4	149	doid[1] == len - 2) {
7e82606e	150	goid.elements = doid + 2;
7e82606e	151	goid.length = len - 2;
6fc2ad02	152	gss_test_oid_set_member(&ms, &goid, supported,
	153	&present);
	154	} else {
	155	logit("Badly formed OID received");
7cac2b65	156	}
7cac2b65	157	} while (mechs > 0 && !present);
	158
	159	gss_release_oid_set(&ms, &supported);
	160
	161	if (!present) {
	162	xfree(doid);
fe4ad273	163	authctxt->server_caused_failure = 1;
7cac2b65	164	return (0);
	165	}
	166
7e82606e	167	if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
7cac2b65	168	xfree(doid);
fe4ad273	169	authctxt->server_caused_failure = 1;
7cac2b65	170	return (0);
23987cb8	171	}
b59afbfe	172
08822d99	173	authctxt->methoddata = (void *)ctxt;
b59afbfe	174
7cac2b65	175	packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
23987cb8	176
540d72c3	177	/* Return the OID that we received */
7cac2b65	178	packet_put_string(doid, len);
23987cb8	179
7cac2b65	180	packet_send();
7cac2b65	181	xfree(doid);
b59afbfe	182
7cac2b65	183	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
	184	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
	185	authctxt->postponed = 1;
	186
	187	return (0);
b59afbfe	188	}
	189
	190	static void
	191	input_gssapi_token(int type, u_int32_t plen, void *ctxt)
	192	{
7cac2b65	193	Authctxt *authctxt = ctxt;
	194	Gssctxt *gssctxt;
	195	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	196	gss_buffer_desc recv_tok;
147c00cc	197	OM_uint32 maj_status, min_status, flags=0;
7cac2b65	198	u_int len;
	199
	200	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	201	fatal("No authentication or GSSAPI context");
	202
	203	gssctxt = authctxt->methoddata;
	204	recv_tok.value = packet_get_string(&len);
	205	recv_tok.length = len; /* u_int vs. size_t */
	206
	207	packet_check_eom();
	208
	209	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
540d72c3	210	&send_tok, &flags));
7cac2b65	211
	212	xfree(recv_tok.value);
	213
	214	if (GSS_ERROR(maj_status)) {
e23e524c	215	ssh_gssapi_userauth_error(gssctxt);
e23e524c	216	if (send_tok.length != 0) {
e23e524c	217	packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
7cac2b65	218	packet_put_string(send_tok.value, send_tok.length);
	219	packet_send();
	220	}
	221	authctxt->postponed = 0;
7cac2b65	222	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
540d72c3	223	userauth_finish(authctxt, 0,
	224	gssapi_with_mic ? "gssapi-with-mic" :
	225	"gssapi");
7cac2b65	226	} else {
7cac2b65	227	if (send_tok.length != 0) {
7cac2b65	228	packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
	229	packet_put_string(send_tok.value, send_tok.length);
	230	packet_send();
	231	}
	232	if (maj_status == GSS_S_COMPLETE) {
7cac2b65	233	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
540d72c3	234	if (flags & GSS_C_INTEG_FLAG && gssapi_with_mic)
	235	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
	236	&input_gssapi_mic);
	237	else
	238	dispatch_set(
	239	SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
	240	&input_gssapi_exchange_complete);
7cac2b65	241	}
	242	}
	243
	244	gss_release_buffer(&min_status, &send_tok);
e23e524c	245	}
23987cb8	246
e23e524c	247	static void
	248	input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
	249	{
7cac2b65	250	Authctxt *authctxt = ctxt;
	251	Gssctxt *gssctxt;
	252	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	253	gss_buffer_desc recv_tok;
	254	OM_uint32 maj_status;
	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	recv_tok.value = packet_get_string(&len);
	262	recv_tok.length = len;
	263
	264	packet_check_eom();
	265
	266	/* Push the error token into GSSAPI to see what it says */
	267	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
	268	&send_tok, NULL));
	269
	270	xfree(recv_tok.value);
e23e524c	271
e23e524c	272	/* We can't return anything to the client, even if we wanted to */
e23e524c	273	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
7cac2b65	274	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
e23e524c	275
e23e524c	276	/* The client will have already moved on to the next auth */
7cac2b65	277
7cac2b65	278	gss_release_buffer(&maj_status, &send_tok);
b59afbfe	279	}
b59afbfe	280
540d72c3	281	static void
	282	gssapi_set_implicit_username(Authctxt *authctxt)
	283	{
4f1e213f	284	if ((authctxt->user == NULL) \|\| (authctxt->user[0] == '\0')) {
540d72c3	285	char *lname = NULL;
	286	PRIVSEP(ssh_gssapi_localname(&lname));
	287	if (lname && lname[0] != '\0') {
4f1e213f	288	if (authctxt->user) xfree(authctxt->user);
540d72c3	289	authctxt->user = lname;
	290	debug("set username to %s from gssapi context", lname);
	291	authctxt->pw = PRIVSEP(getpwnamallow(authctxt->user));
5217e987	292	if (authctxt->pw) {
	293	authctxt->valid = 1;
	294	}
540d72c3	295	} else {
540d72c3	296	debug("failed to set username from gssapi context");
d9e17760	297	packet_send_debug("failed to set username from gssapi context");
540d72c3	298	}
	299	}
	300	if (authctxt->pw) {
	301	#ifdef USE_PAM
147c00cc	302	if (options.use_pam)
5217e987	303	PRIVSEP(start_pam(authctxt));
540d72c3	304	#endif
	305	}
	306	}
	307
7cac2b65	308	/*
7cac2b65	309	* This is called when the client thinks we've completed authentication.
b59afbfe	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	*/
7cac2b65	313
b59afbfe	314	static void
	315	input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
	316	{
7cac2b65	317	Authctxt *authctxt = ctxt;
	318	Gssctxt *gssctxt;
	319	int authenticated;
	320
b59afbfe	321	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
7cac2b65	322	fatal("No authentication or GSSAPI context");
7cac2b65	323
540d72c3	324	gssapi_set_implicit_username(authctxt);
d13dfff4	325
7cac2b65	326	gssctxt = authctxt->methoddata;
7cac2b65	327
7cac2b65	328	/*
540d72c3	329	* We don't need to check the status, because we're only enabled in
540d72c3	330	* the dispatcher once the exchange is complete
b59afbfe	331	*/
b59afbfe	332
7cac2b65	333	packet_check_eom();
7cac2b65	334
941f3f29	335	/* user should be set if valid but we double-check here */
941f3f29	336	if (authctxt->valid && authctxt->user && authctxt->user[0]) {
540d72c3	337	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	338	} else {
	339	authenticated = 0;
	340	}
b59afbfe	341
7cac2b65	342	authctxt->postponed = 0;
	343	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	344	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
540d72c3	345	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
7cac2b65	346	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
540d72c3	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))))
941f3f29	392	if (authctxt->valid && authctxt->user && authctxt->user[0]) {
540d72c3	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");
b59afbfe	409	}
b59afbfe	410
23987cb8	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) {
	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);
	425	}
	426	}
	427
b59afbfe	428	Authmethod method_external = {
	429	"external-keyx",
	430	userauth_external,
	431	&options.gss_authentication
	432	};
	433
fe4ad273	434	Authmethod method_gsskeyex = {
	435	"gssapi-keyex",
	436	userauth_gsskeyex,
	437	&options.gss_authentication
	438	};
	439
b59afbfe	440	Authmethod method_gssapi = {
540d72c3	441	"gssapi-with-mic",
	442	userauth_gssapi_with_mic,
	443	&options.gss_authentication
	444	};
	445
	446	Authmethod method_gssapi_compat = {
7cac2b65	447	"gssapi",
540d72c3	448	userauth_gssapi_without_mic,
7cac2b65	449	&options.gss_authentication
b59afbfe	450	};
	451
	452	#endif /* GSSAPI */