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