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

/*	$OpenBSD: gss-serv-krb5.c,v 1.2 2003/11/21 11:57:03 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
#ifdef KRB5

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

#include "ssh-gss.h"

extern ServerOptions options;

#ifdef HEIMDAL
# include <krb5.h>
#else
# ifdef HAVE_GSSAPI_KRB5
#  include <gssapi_krb5.h>
# elif HAVE_GSSAPI_GSSAPI_KRB5
#  include <gssapi/gssapi_krb5.h>
# endif
#endif

static krb5_context krb_context = NULL;
static int ssh_gssapi_krb5_init();
static int ssh_gssapi_krb5_userok(ssh_gssapi_client *client, char *name);
static int ssh_gssapi_krb5_localname(ssh_gssapi_client *client, char **user);
static void ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client);

ssh_gssapi_mech gssapi_kerberos_mech = {
	"toWM5Slw5Ew8Mqkay+al2g==",
	"Kerberos",
	{9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"},
	NULL,
	&ssh_gssapi_krb5_userok,
	&ssh_gssapi_krb5_localname,
	&ssh_gssapi_krb5_storecreds
};

ssh_gssapi_mech gssapi_kerberos_mech_old = {
	"Se3H81ismmOC3OE+FwYCiQ==",
	"Kerberos",
	{9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"},
	&ssh_gssapi_krb5_init,
	&ssh_gssapi_krb5_userok,
	&ssh_gssapi_krb5_localname,
	&ssh_gssapi_krb5_storecreds
};

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

static int
ssh_gssapi_krb5_init()
{
	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;
	}
#ifdef KRB5_INIT_ETS
	krb5_init_ets(krb_context);
#endif

	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;
}


/* Retrieve the local username associated with a set of Kerberos 
 * credentials. Hopefully we can use this for the 'empty' username
 * logins discussed in the draft  */
static int
ssh_gssapi_krb5_localname(ssh_gssapi_client *client, char **user) {
	krb5_principal princ;
	int retval;
	
	if (ssh_gssapi_krb5_init() == 0)
		return 0;

	if ((retval=krb5_parse_name(krb_context, client->displayname.value, 
				    &princ))) {
		logit("krb5_parse_name(): %.100s", 
			krb5_get_err_text(krb_context,retval));
		return 0;
	}
	
	/* We've got to return a malloc'd string */
	*user = (char *)xmalloc(256);
	if (krb5_aname_to_localname(krb_context, princ, 256, *user)) {
		xfree(*user);
		*user = NULL;
		return(0);
	}
	
	return(1);
}
	
/* 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;
	gss_cred_id_t krb5_cred_handle;
	int len;

	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
	{
		int tmpfd;
		char ccname[40];

		snprintf(ccname, sizeof(ccname),
		    "FILE:/tmp/krb5cc_%d_XXXXXX", geteuid());

		if ((tmpfd = mkstemp(ccname + strlen("FILE:"))) == -1) {
			logit("mkstemp(): %.100s", strerror(errno));
			problem = errno;
			return;
		}
		if (fchmod(tmpfd, S_IRUSR | S_IWUSR) == -1) {
			logit("fchmod(): %.100s", strerror(errno));
			close(tmpfd);
			problem = errno;
			return;
		}
		close(tmpfd);
		if ((problem = krb5_cc_resolve(krb_context, ccname, &ccache))) {
			logit("krb5_cc_resolve(): %.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);

#ifdef MECHGLUE
	krb5_cred_handle =
	    __gss_get_mechanism_cred(client->creds,
				     &(gssapi_kerberos_mech.oid));
#else
	krb5_cred_handle = client->creds;
#endif

	if ((maj_status = gss_krb5_copy_ccache(&min_status, 
	    krb5_cred_handle, ccache))) {
		logit("gss_krb5_copy_ccache() failed");
		krb5_cc_destroy(krb_context, ccache);
		return;
	}

	client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache));
	client->store.envvar = "KRB5CCNAME";
	len = strlen(client->store.filename) + 6;
	client->store.envval = xmalloc(len);
	snprintf(client->store.envval, len, "FILE:%s", client->store.filename);

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

	krb5_cc_close(krb_context, ccache);

	return;
}

#endif /* KRB5 */

#endif /* GSSAPI */
Commit	Line	Data
540d72c3	1	/* $OpenBSD: gss-serv-krb5.c,v 1.2 2003/11/21 11:57:03 djm Exp $ */
7cac2b65	2
f4b9ce42	3	/*
	4	* Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
	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
	32	#include "auth.h"
f4b9ce42	33	#include "xmalloc.h"
	34	#include "log.h"
	35	#include "servconf.h"
	36
	37	#include "ssh-gss.h"
	38
	39	extern ServerOptions options;
	40
	41	#ifdef HEIMDAL
540d72c3	42	# include <krb5.h>
f4b9ce42	43	#else
540d72c3	44	# ifdef HAVE_GSSAPI_KRB5
	45	# include <gssapi_krb5.h>
	46	# elif HAVE_GSSAPI_GSSAPI_KRB5
	47	# include <gssapi/gssapi_krb5.h>
	48	# endif
f4b9ce42	49	#endif
	50
	51	static krb5_context krb_context = NULL;
83059c7b	52	static int ssh_gssapi_krb5_init();
	53	static int ssh_gssapi_krb5_userok(ssh_gssapi_client client, char name);
	54	static int ssh_gssapi_krb5_localname(ssh_gssapi_client client, char *user);
	55	static void ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client);
	56
	57	ssh_gssapi_mech gssapi_kerberos_mech = {
	58	"toWM5Slw5Ew8Mqkay+al2g==",
	59	"Kerberos",
	60	{9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"},
	61	NULL,
	62	&ssh_gssapi_krb5_userok,
	63	&ssh_gssapi_krb5_localname,
	64	&ssh_gssapi_krb5_storecreds
	65	};
	66
	67	ssh_gssapi_mech gssapi_kerberos_mech_old = {
	68	"Se3H81ismmOC3OE+FwYCiQ==",
	69	"Kerberos",
	70	{9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"},
	71	&ssh_gssapi_krb5_init,
	72	&ssh_gssapi_krb5_userok,
	73	&ssh_gssapi_krb5_localname,
	74	&ssh_gssapi_krb5_storecreds
	75	};
f4b9ce42	76
7cac2b65	77	/* Initialise the krb5 library, for the stuff that GSSAPI won't do */
f4b9ce42	78
540d72c3	79	static int
7cac2b65	80	ssh_gssapi_krb5_init()
7cac2b65	81	{
f4b9ce42	82	krb5_error_code problem;
7cac2b65	83
7cac2b65	84	if (krb_context != NULL)
f4b9ce42	85	return 1;
7cac2b65	86
f4b9ce42	87	problem = krb5_init_context(&krb_context);
f4b9ce42	88	if (problem) {
7cac2b65	89	logit("Cannot initialize krb5 context");
f4b9ce42	90	return 0;
f4b9ce42	91	}
12a403af	92	#ifdef KRB5_INIT_ETS
f4b9ce42	93	krb5_init_ets(krb_context);
12a403af	94	#endif
f4b9ce42	95
7cac2b65	96	return 1;
7cac2b65	97	}
f4b9ce42	98
7cac2b65	99	/* Check if this user is OK to login. This only works with krb5 - other
f4b9ce42	100	* GSSAPI mechanisms will need their own.
	101	* Returns true if the user is OK to log in, otherwise returns 0
	102	*/
	103
	104	static int
7cac2b65	105	ssh_gssapi_krb5_userok(ssh_gssapi_client client, char name)
7cac2b65	106	{
f4b9ce42	107	krb5_principal princ;
	108	int retval;
	109
	110	if (ssh_gssapi_krb5_init() == 0)
	111	return 0;
7cac2b65	112
	113	if ((retval = krb5_parse_name(krb_context, client->exportedname.value,
	114	&princ))) {
	115	logit("krb5_parse_name(): %.100s",
	116	krb5_get_err_text(krb_context, retval));
f4b9ce42	117	return 0;
	118	}
	119	if (krb5_kuserok(krb_context, princ, name)) {
	120	retval = 1;
7cac2b65	121	logit("Authorized to %s, krb5 principal %s (krb5_kuserok)",
	122	name, (char *)client->displayname.value);
	123	} else
f4b9ce42	124	retval = 0;
7cac2b65	125
f4b9ce42	126	krb5_free_principal(krb_context, princ);
	127	return retval;
	128	}
	129
7cac2b65	130
f4b9ce42	131	/* Retrieve the local username associated with a set of Kerberos
	132	* credentials. Hopefully we can use this for the 'empty' username
	133	* logins discussed in the draft */
	134	static int
	135	ssh_gssapi_krb5_localname(ssh_gssapi_client client, char *user) {
	136	krb5_principal princ;
	137	int retval;
	138
	139	if (ssh_gssapi_krb5_init() == 0)
	140	return 0;
	141
7cac2b65	142	if ((retval=krb5_parse_name(krb_context, client->displayname.value,
f4b9ce42	143	&princ))) {
7cac2b65	144	logit("krb5_parse_name(): %.100s",
f4b9ce42	145	krb5_get_err_text(krb_context,retval));
	146	return 0;
	147	}
	148
	149	/* We've got to return a malloc'd string */
	150	user = (char )xmalloc(256);
	151	if (krb5_aname_to_localname(krb_context, princ, 256, *user)) {
	152	xfree(*user);
	153	*user = NULL;
	154	return(0);
	155	}
	156
	157	return(1);
	158	}
	159
7cac2b65	160	/* This writes out any forwarded credentials from the structure populated
7cac2b65	161	* during userauth. Called after we have setuid to the user */
f4b9ce42	162
f4b9ce42	163	static void
7cac2b65	164	ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
7cac2b65	165	{
f4b9ce42	166	krb5_ccache ccache;
	167	krb5_error_code problem;
	168	krb5_principal princ;
7cac2b65	169	OM_uint32 maj_status, min_status;
81d08144	170	gss_cred_id_t krb5_cred_handle;
540d72c3	171	int len;
7cac2b65	172
	173	if (client->creds == NULL) {
	174	debug("No credentials stored");
f4b9ce42	175	return;
f4b9ce42	176	}
7cac2b65	177
f4b9ce42	178	if (ssh_gssapi_krb5_init() == 0)
	179	return;
	180
7cac2b65	181	#ifdef HEIMDAL
	182	if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) {
	183	logit("krb5_cc_gen_new(): %.100s",
	184	krb5_get_err_text(krb_context, problem));
f4b9ce42	185	return;
f4b9ce42	186	}
7cac2b65	187	#else
	188	{
	189	int tmpfd;
	190	char ccname[40];
540d72c3	191
540d72c3	192	snprintf(ccname, sizeof(ccname),
7cac2b65	193	"FILE:/tmp/krb5cc_%d_XXXXXX", geteuid());
540d72c3	194
7cac2b65	195	if ((tmpfd = mkstemp(ccname + strlen("FILE:"))) == -1) {
	196	logit("mkstemp(): %.100s", strerror(errno));
	197	problem = errno;
	198	return;
	199	}
	200	if (fchmod(tmpfd, S_IRUSR \| S_IWUSR) == -1) {
	201	logit("fchmod(): %.100s", strerror(errno));
	202	close(tmpfd);
	203	problem = errno;
	204	return;
	205	}
	206	close(tmpfd);
	207	if ((problem = krb5_cc_resolve(krb_context, ccname, &ccache))) {
	208	logit("krb5_cc_resolve(): %.100s",
	209	krb5_get_err_text(krb_context, problem));
	210	return;
	211	}
	212	}
	213	#endif /* #ifdef HEIMDAL */
	214
540d72c3	215	if ((problem = krb5_parse_name(krb_context,
7cac2b65	216	client->exportedname.value, &princ))) {
	217	logit("krb5_parse_name(): %.100s",
	218	krb5_get_err_text(krb_context, problem));
	219	krb5_cc_destroy(krb_context, ccache);
	220	return;
	221	}
	222
f4b9ce42	223	if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) {
7cac2b65	224	logit("krb5_cc_initialize(): %.100s",
	225	krb5_get_err_text(krb_context, problem));
	226	krb5_free_principal(krb_context, princ);
	227	krb5_cc_destroy(krb_context, ccache);
f4b9ce42	228	return;
f4b9ce42	229	}
7cac2b65	230
7cac2b65	231	krb5_free_principal(krb_context, princ);
f4b9ce42	232
81d08144	233	#ifdef MECHGLUE
	234	krb5_cred_handle =
	235	__gss_get_mechanism_cred(client->creds,
	236	&(gssapi_kerberos_mech.oid));
	237	#else
2af4b8d5	238	krb5_cred_handle = client->creds;
81d08144	239	#endif
81d08144	240
f4b9ce42	241	if ((maj_status = gss_krb5_copy_ccache(&min_status,
7cac2b65	242	krb5_cred_handle, ccache))) {
	243	logit("gss_krb5_copy_ccache() failed");
	244	krb5_cc_destroy(krb_context, ccache);
f4b9ce42	245	return;
f4b9ce42	246	}
7cac2b65	247
	248	client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache));
	249	client->store.envvar = "KRB5CCNAME";
540d72c3	250	len = strlen(client->store.filename) + 6;
	251	client->store.envval = xmalloc(len);
	252	snprintf(client->store.envval, len, "FILE:%s", client->store.filename);
f4b9ce42	253
f4b9ce42	254	#ifdef USE_PAM
7cac2b65	255	if (options.use_pam)
540d72c3	256	do_pam_putenv(client->store.envvar, client->store.envval);
f4b9ce42	257	#endif
f4b9ce42	258
7cac2b65	259	krb5_cc_close(krb_context, ccache);
f4b9ce42	260
	261	return;
	262	}
	263
f4b9ce42	264	#endif /* KRB5 */
	265
	266	#endif /* GSSAPI */