[openssh.git] / 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;

/* 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;
	}
	krb5_init_ets(krb_context);

	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;

	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);

	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;
	}

	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;
}

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
};

#endif /* KRB5 */

#endif /* GSSAPI */
Commit	Line	Data
aff51935	1	/* $OpenBSD: gss-serv-krb5.c,v 1.2 2003/11/21 11:57:03 djm Exp $ */
7364bd04	2
	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"
	33	#include "xmalloc.h"
	34	#include "log.h"
	35	#include "servconf.h"
	36
	37	#include "ssh-gss.h"
	38
	39	extern ServerOptions options;
	40
749560dd	41	#ifdef HEIMDAL
071970fb	42	# include <krb5.h>
749560dd	43	#else
071970fb	44	# ifdef HAVE_GSSAPI_KRB5
	45	# include <gssapi_krb5.h>
	46	# elif HAVE_GSSAPI_GSSAPI_KRB5
	47	# include <gssapi/gssapi_krb5.h>
	48	# endif
749560dd	49	#endif
7364bd04	50
	51	static krb5_context krb_context = NULL;
	52
	53	/* Initialise the krb5 library, for the stuff that GSSAPI won't do */
	54
aff51935	55	static int
7364bd04	56	ssh_gssapi_krb5_init()
	57	{
	58	krb5_error_code problem;
	59
	60	if (krb_context != NULL)
	61	return 1;
	62
	63	problem = krb5_init_context(&krb_context);
	64	if (problem) {
	65	logit("Cannot initialize krb5 context");
	66	return 0;
	67	}
	68	krb5_init_ets(krb_context);
	69
	70	return 1;
	71	}
	72
	73	/* Check if this user is OK to login. This only works with krb5 - other
	74	* GSSAPI mechanisms will need their own.
	75	* Returns true if the user is OK to log in, otherwise returns 0
	76	*/
	77
	78	static int
	79	ssh_gssapi_krb5_userok(ssh_gssapi_client client, char name)
	80	{
	81	krb5_principal princ;
	82	int retval;
	83
	84	if (ssh_gssapi_krb5_init() == 0)
	85	return 0;
	86
	87	if ((retval = krb5_parse_name(krb_context, client->exportedname.value,
	88	&princ))) {
	89	logit("krb5_parse_name(): %.100s",
	90	krb5_get_err_text(krb_context, retval));
	91	return 0;
	92	}
	93	if (krb5_kuserok(krb_context, princ, name)) {
	94	retval = 1;
	95	logit("Authorized to %s, krb5 principal %s (krb5_kuserok)",
	96	name, (char *)client->displayname.value);
	97	} else
	98	retval = 0;
	99
	100	krb5_free_principal(krb_context, princ);
	101	return retval;
	102	}
	103
	104
	105	/* This writes out any forwarded credentials from the structure populated
	106	* during userauth. Called after we have setuid to the user */
	107
	108	static void
	109	ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
	110	{
	111	krb5_ccache ccache;
	112	krb5_error_code problem;
	113	krb5_principal princ;
	114	OM_uint32 maj_status, min_status;
5d464804	115	int len;
7364bd04	116
	117	if (client->creds == NULL) {
	118	debug("No credentials stored");
	119	return;
	120	}
	121
	122	if (ssh_gssapi_krb5_init() == 0)
	123	return;
	124
749560dd	125	#ifdef HEIMDAL
7364bd04	126	if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) {
	127	logit("krb5_cc_gen_new(): %.100s",
	128	krb5_get_err_text(krb_context, problem));
	129	return;
	130	}
749560dd	131	#else
	132	{
	133	int tmpfd;
	134	char ccname[40];
aff51935	135
aff51935	136	snprintf(ccname, sizeof(ccname),
749560dd	137	"FILE:/tmp/krb5cc_%d_XXXXXX", geteuid());
aff51935	138
749560dd	139	if ((tmpfd = mkstemp(ccname + strlen("FILE:"))) == -1) {
	140	logit("mkstemp(): %.100s", strerror(errno));
	141	problem = errno;
	142	return;
	143	}
	144	if (fchmod(tmpfd, S_IRUSR \| S_IWUSR) == -1) {
	145	logit("fchmod(): %.100s", strerror(errno));
	146	close(tmpfd);
	147	problem = errno;
	148	return;
	149	}
	150	close(tmpfd);
	151	if ((problem = krb5_cc_resolve(krb_context, ccname, &ccache))) {
	152	logit("krb5_cc_resolve(): %.100s",
	153	krb5_get_err_text(krb_context, problem));
	154	return;
	155	}
	156	}
	157	#endif /* #ifdef HEIMDAL */
7364bd04	158
aff51935	159	if ((problem = krb5_parse_name(krb_context,
7364bd04	160	client->exportedname.value, &princ))) {
	161	logit("krb5_parse_name(): %.100s",
	162	krb5_get_err_text(krb_context, problem));
	163	krb5_cc_destroy(krb_context, ccache);
	164	return;
	165	}
	166
	167	if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) {
	168	logit("krb5_cc_initialize(): %.100s",
	169	krb5_get_err_text(krb_context, problem));
	170	krb5_free_principal(krb_context, princ);
	171	krb5_cc_destroy(krb_context, ccache);
	172	return;
	173	}
	174
	175	krb5_free_principal(krb_context, princ);
	176
aff51935	177	if ((maj_status = gss_krb5_copy_ccache(&min_status,
7364bd04	178	client->creds, ccache))) {
	179	logit("gss_krb5_copy_ccache() failed");
	180	krb5_cc_destroy(krb_context, ccache);
	181	return;
	182	}
	183
	184	client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache));
	185	client->store.envvar = "KRB5CCNAME";
5d464804	186	len = strlen(client->store.filename) + 6;
	187	client->store.envval = xmalloc(len);
	188	snprintf(client->store.envval, len, "FILE:%s", client->store.filename);
7364bd04	189
749560dd	190	#ifdef USE_PAM
749560dd	191	if (options.use_pam)
5d464804	192	do_pam_putenv(client->store.envvar, client->store.envval);
749560dd	193	#endif
749560dd	194
7364bd04	195	krb5_cc_close(krb_context, ccache);
	196
	197	return;
	198	}
	199
	200	ssh_gssapi_mech gssapi_kerberos_mech = {
	201	"toWM5Slw5Ew8Mqkay+al2g==",
	202	"Kerberos",
	203	{9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"},
	204	NULL,
	205	&ssh_gssapi_krb5_userok,
	206	NULL,
	207	&ssh_gssapi_krb5_storecreds
	208	};
	209
	210	#endif /* KRB5 */
	211
	212	#endif /* GSSAPI */