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

/* $OpenBSD: gss-serv-krb5.c,v 1.6 2006/07/02 18:36:47 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>
#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;

	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;
	}

	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
6955279c	1	/* $OpenBSD: gss-serv-krb5.c,v 1.6 2006/07/02 18:36:47 stevesk 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
a8d3dd47	44	# ifdef HAVE_GSSAPI_KRB5_H
071970fb	45	# include <gssapi_krb5.h>
a8d3dd47	46	# elif HAVE_GSSAPI_GSSAPI_KRB5_H
071970fb	47	# include <gssapi/gssapi_krb5.h>
071970fb	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
d2e302d7	56	ssh_gssapi_krb5_init(void)
7364bd04	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	}
7364bd04	68
	69	return 1;
	70	}
	71
	72	/* Check if this user is OK to login. This only works with krb5 - other
	73	* GSSAPI mechanisms will need their own.
	74	* Returns true if the user is OK to log in, otherwise returns 0
	75	*/
	76
	77	static int
	78	ssh_gssapi_krb5_userok(ssh_gssapi_client client, char name)
	79	{
	80	krb5_principal princ;
	81	int retval;
	82
	83	if (ssh_gssapi_krb5_init() == 0)
	84	return 0;
	85
	86	if ((retval = krb5_parse_name(krb_context, client->exportedname.value,
	87	&princ))) {
	88	logit("krb5_parse_name(): %.100s",
	89	krb5_get_err_text(krb_context, retval));
	90	return 0;
	91	}
	92	if (krb5_kuserok(krb_context, princ, name)) {
	93	retval = 1;
	94	logit("Authorized to %s, krb5 principal %s (krb5_kuserok)",
	95	name, (char *)client->displayname.value);
	96	} else
	97	retval = 0;
	98
	99	krb5_free_principal(krb_context, princ);
	100	return retval;
	101	}
	102
	103
	104	/* This writes out any forwarded credentials from the structure populated
	105	* during userauth. Called after we have setuid to the user */
	106
	107	static void
	108	ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
	109	{
	110	krb5_ccache ccache;
	111	krb5_error_code problem;
	112	krb5_principal princ;
	113	OM_uint32 maj_status, min_status;
5d464804	114	int len;
7364bd04	115
	116	if (client->creds == NULL) {
	117	debug("No credentials stored");
	118	return;
	119	}
	120
	121	if (ssh_gssapi_krb5_init() == 0)
	122	return;
	123
749560dd	124	#ifdef HEIMDAL
7364bd04	125	if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) {
	126	logit("krb5_cc_gen_new(): %.100s",
	127	krb5_get_err_text(krb_context, problem));
	128	return;
	129	}
749560dd	130	#else
937eb918	131	if ((problem = ssh_krb5_cc_gen(krb_context, &ccache))) {
	132	logit("ssh_krb5_cc_gen(): %.100s",
	133	krb5_get_err_text(krb_context, problem));
	134	return;
749560dd	135	}
749560dd	136	#endif /* #ifdef HEIMDAL */
7364bd04	137
aff51935	138	if ((problem = krb5_parse_name(krb_context,
7364bd04	139	client->exportedname.value, &princ))) {
	140	logit("krb5_parse_name(): %.100s",
	141	krb5_get_err_text(krb_context, problem));
	142	krb5_cc_destroy(krb_context, ccache);
	143	return;
	144	}
	145
	146	if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) {
	147	logit("krb5_cc_initialize(): %.100s",
	148	krb5_get_err_text(krb_context, problem));
	149	krb5_free_principal(krb_context, princ);
	150	krb5_cc_destroy(krb_context, ccache);
	151	return;
	152	}
	153
	154	krb5_free_principal(krb_context, princ);
	155
aff51935	156	if ((maj_status = gss_krb5_copy_ccache(&min_status,
7364bd04	157	client->creds, ccache))) {
	158	logit("gss_krb5_copy_ccache() failed");
	159	krb5_cc_destroy(krb_context, ccache);
	160	return;
	161	}
	162
	163	client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache));
	164	client->store.envvar = "KRB5CCNAME";
5d464804	165	len = strlen(client->store.filename) + 6;
	166	client->store.envval = xmalloc(len);
	167	snprintf(client->store.envval, len, "FILE:%s", client->store.filename);
7364bd04	168
749560dd	169	#ifdef USE_PAM
749560dd	170	if (options.use_pam)
5d464804	171	do_pam_putenv(client->store.envvar, client->store.envval);
749560dd	172	#endif
749560dd	173
7364bd04	174	krb5_cc_close(krb_context, ccache);
	175
	176	return;
	177	}
	178
	179	ssh_gssapi_mech gssapi_kerberos_mech = {
	180	"toWM5Slw5Ew8Mqkay+al2g==",
	181	"Kerberos",
	182	{9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"},
	183	NULL,
	184	&ssh_gssapi_krb5_userok,
	185	NULL,
	186	&ssh_gssapi_krb5_storecreds
	187	};
	188
	189	#endif /* KRB5 */
	190
	191	#endif /* GSSAPI */