[gssapi-openssh.git] / openssh / gss-serv-krb5.c

/* $OpenBSD: gss-serv-krb5.c,v 1.7 2006/08/03 03:34:42 deraadt 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
#ifdef KRB5

#include <sys/types.h>

#include <stdarg.h>
#include <string.h>

#include "xmalloc.h"
#include "key.h"
#include "hostfile.h"
#include "auth.h"
#include "log.h"
#include "servconf.h"

#include "buffer.h"
#include "ssh-gss.h"

extern ServerOptions options;

#ifdef HEIMDAL
# include <krb5.h>
#else
# ifdef HAVE_GSSAPI_KRB5_H
#  include <gssapi_krb5.h>
# elif HAVE_GSSAPI_GSSAPI_KRB5_H
#  include <gssapi/gssapi_krb5.h>
# endif
#endif

static krb5_context krb_context = NULL;

/* Initialise the krb5 library, for the stuff that GSSAPI won't do */

static int
ssh_gssapi_krb5_init(void)
{
	krb5_error_code problem;

	if (krb_context != NULL)
		return 1;

	problem = krb5_init_context(&krb_context);
	if (problem) {
		logit("Cannot initialize krb5 context");
		return 0;
	}

	return 1;
}

/* Check if this user is OK to login. This only works with krb5 - other
 * GSSAPI mechanisms will need their own.
 * Returns true if the user is OK to log in, otherwise returns 0
 */

static int
ssh_gssapi_krb5_userok(ssh_gssapi_client *client, char *name)
{
	krb5_principal princ;
	int retval;

	if (ssh_gssapi_krb5_init() == 0)
		return 0;

	if ((retval = krb5_parse_name(krb_context, client->exportedname.value,
	    &princ))) {
		logit("krb5_parse_name(): %.100s",
		    krb5_get_err_text(krb_context, retval));
		return 0;
	}
	if (krb5_kuserok(krb_context, princ, name)) {
		retval = 1;
		logit("Authorized to %s, krb5 principal %s (krb5_kuserok)",
		    name, (char *)client->displayname.value);
	} else
		retval = 0;

	krb5_free_principal(krb_context, princ);
	return retval;
}


/* This writes out any forwarded credentials from the structure populated
 * during userauth. Called after we have setuid to the user */

static void
ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
{
	krb5_ccache ccache;
	krb5_error_code problem;
	krb5_principal princ;
	OM_uint32 maj_status, min_status;
	int len;
	const char *new_ccname;

	if (client->creds == NULL) {
		debug("No credentials stored");
		return;
	}

	if (ssh_gssapi_krb5_init() == 0)
		return;

#ifdef HEIMDAL
	if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) {
		logit("krb5_cc_gen_new(): %.100s",
		    krb5_get_err_text(krb_context, problem));
		return;
	}
#else
	if ((problem = ssh_krb5_cc_gen(krb_context, &ccache))) {
		logit("ssh_krb5_cc_gen(): %.100s",
		    krb5_get_err_text(krb_context, problem));
		return;
	}
#endif	/* #ifdef HEIMDAL */

	if ((problem = krb5_parse_name(krb_context,
	    client->exportedname.value, &princ))) {
		logit("krb5_parse_name(): %.100s",
		    krb5_get_err_text(krb_context, problem));
		krb5_cc_destroy(krb_context, ccache);
		return;
	}

	if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) {
		logit("krb5_cc_initialize(): %.100s",
		    krb5_get_err_text(krb_context, problem));
		krb5_free_principal(krb_context, princ);
		krb5_cc_destroy(krb_context, ccache);
		return;
	}

	krb5_free_principal(krb_context, princ);

	if ((maj_status = gss_krb5_copy_ccache(&min_status,
	    client->creds, ccache))) {
		logit("gss_krb5_copy_ccache() failed");
		krb5_cc_destroy(krb_context, ccache);
		return;
	}

	new_ccname = krb5_cc_get_name(krb_context, ccache);

	client->store.envvar = "KRB5CCNAME";
#ifdef USE_CCAPI
	xasprintf(&client->store.envval, "API:%s", new_ccname);
	client->store.filename = NULL;
#else
	xasprintf(&client->store.envval, "FILE:%s", new_ccname);
	client->store.filename = xstrdup(new_ccname);
#endif

#ifdef USE_PAM
	if (options.use_pam)
		do_pam_putenv(client->store.envvar, client->store.envval);
#endif

	krb5_cc_close(krb_context, ccache);

	return;
}

int
ssh_gssapi_krb5_updatecreds(ssh_gssapi_ccache *store, 
    ssh_gssapi_client *client)
{
	krb5_ccache ccache = NULL;
	krb5_principal principal = NULL;
	char *name = NULL;
	krb5_error_code problem;
	OM_uint32 maj_status, min_status;

   	if ((problem = krb5_cc_resolve(krb_context, store->envval, &ccache))) {
                logit("krb5_cc_resolve(): %.100s",
                    krb5_get_err_text(krb_context, problem));
                return 0;
       	}
	
	/* Find out who the principal in this cache is */
	if ((problem = krb5_cc_get_principal(krb_context, ccache, 
	    &principal))) {
		logit("krb5_cc_get_principal(): %.100s",
		    krb5_get_err_text(krb_context, problem));
		krb5_cc_close(krb_context, ccache);
		return 0;
	}

	if ((problem = krb5_unparse_name(krb_context, principal, &name))) {
		logit("krb5_unparse_name(): %.100s",
		    krb5_get_err_text(krb_context, problem));
		krb5_free_principal(krb_context, principal);
		krb5_cc_close(krb_context, ccache);
		return 0;
	}


	if (strcmp(name,client->exportedname.value)!=0) {
		debug("Name in local credentials cache differs. Not storing");
		krb5_free_principal(krb_context, principal);
		krb5_cc_close(krb_context, ccache);
		krb5_free_unparsed_name(krb_context, name);
		return 0;
	}
	krb5_free_unparsed_name(krb_context, name);

	/* Name matches, so lets get on with it! */

	if ((problem = krb5_cc_initialize(krb_context, ccache, principal))) {
		logit("krb5_cc_initialize(): %.100s",
		    krb5_get_err_text(krb_context, problem));
		krb5_free_principal(krb_context, principal);
		krb5_cc_close(krb_context, ccache);
		return 0;
	}

	krb5_free_principal(krb_context, principal);

	if ((maj_status = gss_krb5_copy_ccache(&min_status, client->creds,
	    ccache))) {
		logit("gss_krb5_copy_ccache() failed. Sorry!");
		krb5_cc_close(krb_context, ccache);
		return 0;
	}

	return 1;
}

ssh_gssapi_mech gssapi_kerberos_mech = {
	"toWM5Slw5Ew8Mqkay+al2g==",
	"Kerberos",
	{9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"},
	NULL,
	&ssh_gssapi_krb5_userok,
	NULL,
	&ssh_gssapi_krb5_storecreds,
	&ssh_gssapi_krb5_updatecreds
};

#endif /* KRB5 */

#endif /* GSSAPI */
Commit	Line	Data
9108f8d9	1	/* $OpenBSD: gss-serv-krb5.c,v 1.7 2006/08/03 03:34:42 deraadt Exp $ */
0fff78ff	2
0fff78ff	3	/*
f97edba6	4	* Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
0fff78ff	5	*
	6	* Redistribution and use in source and binary forms, with or without
	7	* modification, are permitted provided that the following conditions
	8	* are met:
	9	* 1. Redistributions of source code must retain the above copyright
	10	* notice, this list of conditions and the following disclaimer.
	11	* 2. Redistributions in binary form must reproduce the above copyright
	12	* notice, this list of conditions and the following disclaimer in the
	13	* documentation and/or other materials provided with the distribution.
	14	*
	15	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
	16	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	17	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	18	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	19	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	20	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	21	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	22	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	23	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	24	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	25	*/
	26
	27	#include "includes.h"
	28
	29	#ifdef GSSAPI
	30	#ifdef KRB5
	31
9108f8d9	32	#include <sys/types.h>
	33
	34	#include <stdarg.h>
	35	#include <string.h>
	36
0fff78ff	37	#include "xmalloc.h"
9108f8d9	38	#include "key.h"
	39	#include "hostfile.h"
	40	#include "auth.h"
0fff78ff	41	#include "log.h"
	42	#include "servconf.h"
	43
9108f8d9	44	#include "buffer.h"
0fff78ff	45	#include "ssh-gss.h"
	46
	47	extern ServerOptions options;
	48
	49	#ifdef HEIMDAL
cdd66111	50	# include <krb5.h>
0fff78ff	51	#else
9108f8d9	52	# ifdef HAVE_GSSAPI_KRB5_H
cdd66111	53	# include <gssapi_krb5.h>
9108f8d9	54	# elif HAVE_GSSAPI_GSSAPI_KRB5_H
cdd66111	55	# include <gssapi/gssapi_krb5.h>
cdd66111	56	# endif
0fff78ff	57	#endif
	58
	59	static krb5_context krb_context = NULL;
	60
	61	/* Initialise the krb5 library, for the stuff that GSSAPI won't do */
	62
cdd66111	63	static int
c9f39d2c	64	ssh_gssapi_krb5_init(void)
0fff78ff	65	{
	66	krb5_error_code problem;
	67
	68	if (krb_context != NULL)
	69	return 1;
	70
	71	problem = krb5_init_context(&krb_context);
	72	if (problem) {
	73	logit("Cannot initialize krb5 context");
	74	return 0;
	75	}
0fff78ff	76
	77	return 1;
	78	}
	79
	80	/* Check if this user is OK to login. This only works with krb5 - other
	81	* GSSAPI mechanisms will need their own.
	82	* Returns true if the user is OK to log in, otherwise returns 0
	83	*/
	84
	85	static int
	86	ssh_gssapi_krb5_userok(ssh_gssapi_client client, char name)
	87	{
	88	krb5_principal princ;
	89	int retval;
	90
	91	if (ssh_gssapi_krb5_init() == 0)
	92	return 0;
	93
	94	if ((retval = krb5_parse_name(krb_context, client->exportedname.value,
	95	&princ))) {
	96	logit("krb5_parse_name(): %.100s",
	97	krb5_get_err_text(krb_context, retval));
	98	return 0;
	99	}
	100	if (krb5_kuserok(krb_context, princ, name)) {
	101	retval = 1;
	102	logit("Authorized to %s, krb5 principal %s (krb5_kuserok)",
	103	name, (char *)client->displayname.value);
	104	} else
	105	retval = 0;
	106
	107	krb5_free_principal(krb_context, princ);
	108	return retval;
	109	}
	110
	111
	112	/* This writes out any forwarded credentials from the structure populated
	113	* during userauth. Called after we have setuid to the user */
	114
	115	static void
	116	ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
	117	{
	118	krb5_ccache ccache;
	119	krb5_error_code problem;
	120	krb5_principal princ;
	121	OM_uint32 maj_status, min_status;
cdd66111	122	int len;
f97edba6	123	const char *new_ccname;
0fff78ff	124
	125	if (client->creds == NULL) {
	126	debug("No credentials stored");
	127	return;
	128	}
	129
	130	if (ssh_gssapi_krb5_init() == 0)
	131	return;
	132
	133	#ifdef HEIMDAL
	134	if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) {
	135	logit("krb5_cc_gen_new(): %.100s",
	136	krb5_get_err_text(krb_context, problem));
	137	return;
	138	}
	139	#else
665a873d	140	if ((problem = ssh_krb5_cc_gen(krb_context, &ccache))) {
	141	logit("ssh_krb5_cc_gen(): %.100s",
	142	krb5_get_err_text(krb_context, problem));
	143	return;
0fff78ff	144	}
	145	#endif /* #ifdef HEIMDAL */
	146
cdd66111	147	if ((problem = krb5_parse_name(krb_context,
0fff78ff	148	client->exportedname.value, &princ))) {
	149	logit("krb5_parse_name(): %.100s",
	150	krb5_get_err_text(krb_context, problem));
	151	krb5_cc_destroy(krb_context, ccache);
	152	return;
	153	}
	154
	155	if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) {
	156	logit("krb5_cc_initialize(): %.100s",
	157	krb5_get_err_text(krb_context, problem));
	158	krb5_free_principal(krb_context, princ);
	159	krb5_cc_destroy(krb_context, ccache);
	160	return;
	161	}
	162
	163	krb5_free_principal(krb_context, princ);
	164
cdd66111	165	if ((maj_status = gss_krb5_copy_ccache(&min_status,
0fff78ff	166	client->creds, ccache))) {
	167	logit("gss_krb5_copy_ccache() failed");
	168	krb5_cc_destroy(krb_context, ccache);
	169	return;
	170	}
	171
f97edba6	172	new_ccname = krb5_cc_get_name(krb_context, ccache);
f97edba6	173
0fff78ff	174	client->store.envvar = "KRB5CCNAME";
f97edba6	175	#ifdef USE_CCAPI
	176	xasprintf(&client->store.envval, "API:%s", new_ccname);
	177	client->store.filename = NULL;
	178	#else
	179	xasprintf(&client->store.envval, "FILE:%s", new_ccname);
	180	client->store.filename = xstrdup(new_ccname);
	181	#endif
0fff78ff	182
	183	#ifdef USE_PAM
	184	if (options.use_pam)
cdd66111	185	do_pam_putenv(client->store.envvar, client->store.envval);
0fff78ff	186	#endif
	187
	188	krb5_cc_close(krb_context, ccache);
	189
	190	return;
	191	}
	192
f97edba6	193	int
	194	ssh_gssapi_krb5_updatecreds(ssh_gssapi_ccache *store,
	195	ssh_gssapi_client *client)
	196	{
	197	krb5_ccache ccache = NULL;
	198	krb5_principal principal = NULL;
	199	char *name = NULL;
	200	krb5_error_code problem;
	201	OM_uint32 maj_status, min_status;
	202
	203	if ((problem = krb5_cc_resolve(krb_context, store->envval, &ccache))) {
	204	logit("krb5_cc_resolve(): %.100s",
	205	krb5_get_err_text(krb_context, problem));
	206	return 0;
	207	}
	208
	209	/* Find out who the principal in this cache is */
	210	if ((problem = krb5_cc_get_principal(krb_context, ccache,
	211	&principal))) {
	212	logit("krb5_cc_get_principal(): %.100s",
	213	krb5_get_err_text(krb_context, problem));
	214	krb5_cc_close(krb_context, ccache);
	215	return 0;
	216	}
	217
	218	if ((problem = krb5_unparse_name(krb_context, principal, &name))) {
	219	logit("krb5_unparse_name(): %.100s",
	220	krb5_get_err_text(krb_context, problem));
	221	krb5_free_principal(krb_context, principal);
	222	krb5_cc_close(krb_context, ccache);
	223	return 0;
	224	}
	225
	226
	227	if (strcmp(name,client->exportedname.value)!=0) {
	228	debug("Name in local credentials cache differs. Not storing");
	229	krb5_free_principal(krb_context, principal);
	230	krb5_cc_close(krb_context, ccache);
	231	krb5_free_unparsed_name(krb_context, name);
	232	return 0;
	233	}
	234	krb5_free_unparsed_name(krb_context, name);
	235
	236	/* Name matches, so lets get on with it! */
	237
	238	if ((problem = krb5_cc_initialize(krb_context, ccache, principal))) {
	239	logit("krb5_cc_initialize(): %.100s",
	240	krb5_get_err_text(krb_context, problem));
	241	krb5_free_principal(krb_context, principal);
	242	krb5_cc_close(krb_context, ccache);
	243	return 0;
	244	}
	245
	246	krb5_free_principal(krb_context, principal);
	247
	248	if ((maj_status = gss_krb5_copy_ccache(&min_status, client->creds,
	249	ccache))) {
	250	logit("gss_krb5_copy_ccache() failed. Sorry!");
	251	krb5_cc_close(krb_context, ccache);
	252	return 0;
	253	}
	254
	255	return 1;
	256	}
257
0fff78ff	258	ssh_gssapi_mech gssapi_kerberos_mech = {
	259	"toWM5Slw5Ew8Mqkay+al2g==",
	260	"Kerberos",
	261	{9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"},
	262	NULL,
	263	&ssh_gssapi_krb5_userok,
	264	NULL,
f97edba6	265	&ssh_gssapi_krb5_storecreds,
f97edba6	266	&ssh_gssapi_krb5_updatecreds
0fff78ff	267	};
	268
	269	#endif /* KRB5 */
	270
	271	#endif /* GSSAPI */