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

/*	$OpenBSD: gss-serv-krb5.c,v 1.4 2005/10/13 19:08:08 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
#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>
#elif !defined(MECHGLUE)
# 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;
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
};

/* 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;
}


/* 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
	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);

#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
08822d99	1	/* $OpenBSD: gss-serv-krb5.c,v 1.4 2005/10/13 19:08:08 stevesk 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>
48a25c13	43	#elif !defined(MECHGLUE)
fe4ad273	44	# ifdef HAVE_GSSAPI_KRB5_H
540d72c3	45	# include <gssapi_krb5.h>
fe4ad273	46	# elif HAVE_GSSAPI_GSSAPI_KRB5_H
540d72c3	47	# include <gssapi/gssapi_krb5.h>
540d72c3	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
7cac2b65	67	/* Initialise the krb5 library, for the stuff that GSSAPI won't do */
f4b9ce42	68
540d72c3	69	static int
7e82606e	70	ssh_gssapi_krb5_init(void)
7cac2b65	71	{
f4b9ce42	72	krb5_error_code problem;
7cac2b65	73
7cac2b65	74	if (krb_context != NULL)
f4b9ce42	75	return 1;
7cac2b65	76
f4b9ce42	77	problem = krb5_init_context(&krb_context);
f4b9ce42	78	if (problem) {
7cac2b65	79	logit("Cannot initialize krb5 context");
f4b9ce42	80	return 0;
f4b9ce42	81	}
f4b9ce42	82
7cac2b65	83	return 1;
7cac2b65	84	}
f4b9ce42	85
7cac2b65	86	/* Check if this user is OK to login. This only works with krb5 - other
f4b9ce42	87	* GSSAPI mechanisms will need their own.
	88	* Returns true if the user is OK to log in, otherwise returns 0
	89	*/
	90
	91	static int
7cac2b65	92	ssh_gssapi_krb5_userok(ssh_gssapi_client client, char name)
7cac2b65	93	{
f4b9ce42	94	krb5_principal princ;
	95	int retval;
	96
	97	if (ssh_gssapi_krb5_init() == 0)
	98	return 0;
7cac2b65	99
	100	if ((retval = krb5_parse_name(krb_context, client->exportedname.value,
	101	&princ))) {
	102	logit("krb5_parse_name(): %.100s",
	103	krb5_get_err_text(krb_context, retval));
f4b9ce42	104	return 0;
	105	}
	106	if (krb5_kuserok(krb_context, princ, name)) {
	107	retval = 1;
7cac2b65	108	logit("Authorized to %s, krb5 principal %s (krb5_kuserok)",
	109	name, (char *)client->displayname.value);
	110	} else
f4b9ce42	111	retval = 0;
7cac2b65	112
f4b9ce42	113	krb5_free_principal(krb_context, princ);
	114	return retval;
	115	}
	116
7cac2b65	117
f4b9ce42	118	/* Retrieve the local username associated with a set of Kerberos
	119	* credentials. Hopefully we can use this for the 'empty' username
	120	* logins discussed in the draft */
	121	static int
	122	ssh_gssapi_krb5_localname(ssh_gssapi_client client, char *user) {
	123	krb5_principal princ;
	124	int retval;
	125
	126	if (ssh_gssapi_krb5_init() == 0)
	127	return 0;
	128
7cac2b65	129	if ((retval=krb5_parse_name(krb_context, client->displayname.value,
f4b9ce42	130	&princ))) {
7cac2b65	131	logit("krb5_parse_name(): %.100s",
f4b9ce42	132	krb5_get_err_text(krb_context,retval));
	133	return 0;
	134	}
	135
	136	/* We've got to return a malloc'd string */
	137	user = (char )xmalloc(256);
	138	if (krb5_aname_to_localname(krb_context, princ, 256, *user)) {
	139	xfree(*user);
	140	*user = NULL;
	141	return(0);
	142	}
	143
	144	return(1);
	145	}
	146
7cac2b65	147	/* This writes out any forwarded credentials from the structure populated
7cac2b65	148	* during userauth. Called after we have setuid to the user */
f4b9ce42	149
f4b9ce42	150	static void
7cac2b65	151	ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
7cac2b65	152	{
f4b9ce42	153	krb5_ccache ccache;
	154	krb5_error_code problem;
	155	krb5_principal princ;
7cac2b65	156	OM_uint32 maj_status, min_status;
81d08144	157	gss_cred_id_t krb5_cred_handle;
540d72c3	158	int len;
7cac2b65	159
	160	if (client->creds == NULL) {
	161	debug("No credentials stored");
f4b9ce42	162	return;
f4b9ce42	163	}
7cac2b65	164
f4b9ce42	165	if (ssh_gssapi_krb5_init() == 0)
	166	return;
	167
7cac2b65	168	#ifdef HEIMDAL
	169	if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) {
	170	logit("krb5_cc_gen_new(): %.100s",
	171	krb5_get_err_text(krb_context, problem));
f4b9ce42	172	return;
f4b9ce42	173	}
7cac2b65	174	#else
2ce0bfe4	175	if ((problem = ssh_krb5_cc_gen(krb_context, &ccache))) {
	176	logit("ssh_krb5_cc_gen(): %.100s",
	177	krb5_get_err_text(krb_context, problem));
	178	return;
7cac2b65	179	}
	180	#endif /* #ifdef HEIMDAL */
	181
540d72c3	182	if ((problem = krb5_parse_name(krb_context,
7cac2b65	183	client->exportedname.value, &princ))) {
	184	logit("krb5_parse_name(): %.100s",
	185	krb5_get_err_text(krb_context, problem));
	186	krb5_cc_destroy(krb_context, ccache);
	187	return;
	188	}
	189
f4b9ce42	190	if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) {
7cac2b65	191	logit("krb5_cc_initialize(): %.100s",
	192	krb5_get_err_text(krb_context, problem));
	193	krb5_free_principal(krb_context, princ);
	194	krb5_cc_destroy(krb_context, ccache);
f4b9ce42	195	return;
f4b9ce42	196	}
7cac2b65	197
7cac2b65	198	krb5_free_principal(krb_context, princ);
f4b9ce42	199
81d08144	200	#ifdef MECHGLUE
	201	krb5_cred_handle =
	202	__gss_get_mechanism_cred(client->creds,
	203	&(gssapi_kerberos_mech.oid));
	204	#else
2af4b8d5	205	krb5_cred_handle = client->creds;
81d08144	206	#endif
81d08144	207
f4b9ce42	208	if ((maj_status = gss_krb5_copy_ccache(&min_status,
7cac2b65	209	krb5_cred_handle, ccache))) {
	210	logit("gss_krb5_copy_ccache() failed");
	211	krb5_cc_destroy(krb_context, ccache);
f4b9ce42	212	return;
f4b9ce42	213	}
7cac2b65	214
	215	client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache));
	216	client->store.envvar = "KRB5CCNAME";
540d72c3	217	len = strlen(client->store.filename) + 6;
	218	client->store.envval = xmalloc(len);
	219	snprintf(client->store.envval, len, "FILE:%s", client->store.filename);
f4b9ce42	220
f4b9ce42	221	#ifdef USE_PAM
7cac2b65	222	if (options.use_pam)
540d72c3	223	do_pam_putenv(client->store.envvar, client->store.envval);
f4b9ce42	224	#endif
f4b9ce42	225
7cac2b65	226	krb5_cc_close(krb_context, ccache);
f4b9ce42	227
	228	return;
	229	}
	230
f4b9ce42	231	#endif /* KRB5 */
	232
	233	#endif /* GSSAPI */