[openssh.git] / auth-krb5.c

/* $OpenBSD: auth-krb5.c,v 1.18 2006/05/06 08:35:40 dtucker Exp $ */
/*
 *    Kerberos v5 authentication and ticket-passing routines.
 *
 * $FreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp $
 */
/*
 * Copyright (c) 2002 Daniel Kouril.  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"

#include "ssh.h"
#include "ssh1.h"
#include "packet.h"
#include "xmalloc.h"
#include "log.h"
#include "servconf.h"
#include "uidswap.h"
#include "auth.h"

#ifdef KRB5
#include <errno.h>
#include <krb5.h>

extern ServerOptions	 options;

static int
krb5_init(void *context)
{
	Authctxt *authctxt = (Authctxt *)context;
	krb5_error_code problem;

	if (authctxt->krb5_ctx == NULL) {
		problem = krb5_init_context(&authctxt->krb5_ctx);
		if (problem)
			return (problem);
	}
	return (0);
}

int
auth_krb5_password(Authctxt *authctxt, const char *password)
{
#ifndef HEIMDAL
	krb5_creds creds;
	krb5_principal server;
#endif
	krb5_error_code problem;
	krb5_ccache ccache = NULL;
	int len;

	temporarily_use_uid(authctxt->pw);

	problem = krb5_init(authctxt);
	if (problem)
		goto out;

	problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name,
		    &authctxt->krb5_user);
	if (problem)
		goto out;

#ifdef HEIMDAL
	problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache);
	if (problem)
		goto out;

	problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
		authctxt->krb5_user);
	if (problem)
		goto out;

	restore_uid();

	problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
	    ccache, password, 1, NULL);

	temporarily_use_uid(authctxt->pw);

	if (problem)
		goto out;

	problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops,
	    &authctxt->krb5_fwd_ccache);
	if (problem)
		goto out;

	problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache,
	    authctxt->krb5_fwd_ccache);
	krb5_cc_destroy(authctxt->krb5_ctx, ccache);
	ccache = NULL;
	if (problem)
		goto out;

#else
	problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds,
	    authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL);
	if (problem)
		goto out;

	problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
	    KRB5_NT_SRV_HST, &server);
	if (problem)
		goto out;

	restore_uid();
	problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server,
	    NULL, NULL, NULL);
	krb5_free_principal(authctxt->krb5_ctx, server);
	temporarily_use_uid(authctxt->pw);
	if (problem)
		goto out;

	if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user,
			  authctxt->pw->pw_name)) {
		problem = -1;
		goto out;
	}

	problem = ssh_krb5_cc_gen(authctxt->krb5_ctx, &authctxt->krb5_fwd_ccache);
	if (problem)
		goto out;

	problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
				     authctxt->krb5_user);
	if (problem)
		goto out;

	problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
				 &creds);
	if (problem)
		goto out;
#endif

	authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);

	len = strlen(authctxt->krb5_ticket_file) + 6;
	authctxt->krb5_ccname = xmalloc(len);
	snprintf(authctxt->krb5_ccname, len, "FILE:%s",
	    authctxt->krb5_ticket_file);

#ifdef USE_PAM
	if (options.use_pam)
		do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname);
#endif

 out:
	restore_uid();

	if (problem) {
		if (ccache)
			krb5_cc_destroy(authctxt->krb5_ctx, ccache);

		if (authctxt->krb5_ctx != NULL && problem!=-1)
			debug("Kerberos password authentication failed: %s",
			    krb5_get_err_text(authctxt->krb5_ctx, problem));
		else
			debug("Kerberos password authentication failed: %d",
			    problem);

		krb5_cleanup_proc(authctxt);

		if (options.kerberos_or_local_passwd)
			return (-1);
		else
			return (0);
	}
	return (authctxt->valid ? 1 : 0);
}

void
krb5_cleanup_proc(Authctxt *authctxt)
{
	debug("krb5_cleanup_proc called");
	if (authctxt->krb5_fwd_ccache) {
		krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
		authctxt->krb5_fwd_ccache = NULL;
	}
	if (authctxt->krb5_user) {
		krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
		authctxt->krb5_user = NULL;
	}
	if (authctxt->krb5_ctx) {
		krb5_free_context(authctxt->krb5_ctx);
		authctxt->krb5_ctx = NULL;
	}
}

#ifndef HEIMDAL
krb5_error_code
ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) {
	int tmpfd, ret;
	char ccname[40];
	mode_t old_umask;

	ret = snprintf(ccname, sizeof(ccname),
	    "FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid());
	if (ret < 0 || (size_t)ret >= sizeof(ccname))
		return ENOMEM;

	old_umask = umask(0177);
	tmpfd = mkstemp(ccname + strlen("FILE:"));
	umask(old_umask);
	if (tmpfd == -1) {
		logit("mkstemp(): %.100s", strerror(errno));
		return errno;
	}

	if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) {
		logit("fchmod(): %.100s", strerror(errno));
		close(tmpfd);
		return errno;
	}
	close(tmpfd);

	return (krb5_cc_resolve(ctx, ccname, ccache));
}
#endif /* !HEIMDAL */
#endif /* KRB5 */
Commit	Line	Data
9188927d	1	/* $OpenBSD: auth-krb5.c,v 1.18 2006/05/06 08:35:40 dtucker Exp $ */
aa9f6a6e	2	/*
aa9f6a6e	3	* Kerberos v5 authentication and ticket-passing routines.
762715ce	4	*
aa9f6a6e	5	* $FreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp $
aa9f6a6e	6	*/
bb15f28b	7	/*
	8	* Copyright (c) 2002 Daniel Kouril. All rights reserved.
	9	*
	10	* Redistribution and use in source and binary forms, with or without
	11	* modification, are permitted provided that the following conditions
	12	* are met:
	13	* 1. Redistributions of source code must retain the above copyright
	14	* notice, this list of conditions and the following disclaimer.
	15	* 2. Redistributions in binary form must reproduce the above copyright
	16	* notice, this list of conditions and the following disclaimer in the
	17	* documentation and/or other materials provided with the distribution.
	18	*
	19	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	20	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	21	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	22	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	23	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	24	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	25	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	26	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	27	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	28	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	29	*/
aa9f6a6e	30
aa9f6a6e	31	#include "includes.h"
93c3b6de	32
aa9f6a6e	33	#include "ssh.h"
	34	#include "ssh1.h"
	35	#include "packet.h"
	36	#include "xmalloc.h"
	37	#include "log.h"
	38	#include "servconf.h"
	39	#include "uidswap.h"
	40	#include "auth.h"
	41
	42	#ifdef KRB5
4352744e	43	#include <errno.h>
aa9f6a6e	44	#include <krb5.h>
	45
	46	extern ServerOptions options;
	47
	48	static int
	49	krb5_init(void *context)
	50	{
	51	Authctxt authctxt = (Authctxt )context;
	52	krb5_error_code problem;
a0105740	53
aa9f6a6e	54	if (authctxt->krb5_ctx == NULL) {
	55	problem = krb5_init_context(&authctxt->krb5_ctx);
	56	if (problem)
	57	return (problem);
aa9f6a6e	58	}
aa9f6a6e	59	return (0);
	60	}
	61
aa9f6a6e	62	int
	63	auth_krb5_password(Authctxt authctxt, const char password)
	64	{
12928e80	65	#ifndef HEIMDAL
	66	krb5_creds creds;
	67	krb5_principal server;
b6453d99	68	#endif
aa9f6a6e	69	krb5_error_code problem;
78e43412	70	krb5_ccache ccache = NULL;
6490a5d5	71	int len;
a0105740	72
aa9f6a6e	73	temporarily_use_uid(authctxt->pw);
a0105740	74
aa9f6a6e	75	problem = krb5_init(authctxt);
	76	if (problem)
	77	goto out;
a0105740	78
aa9f6a6e	79	problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name,
	80	&authctxt->krb5_user);
	81	if (problem)
	82	goto out;
a0105740	83
12928e80	84	#ifdef HEIMDAL
78e43412	85	problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache);
aa9f6a6e	86	if (problem)
aa9f6a6e	87	goto out;
a0105740	88
78e43412	89	problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
78e43412	90	authctxt->krb5_user);
aa9f6a6e	91	if (problem)
aa9f6a6e	92	goto out;
a0105740	93
a0105740	94	restore_uid();
b6453d99	95
aa9f6a6e	96	problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
78e43412	97	ccache, password, 1, NULL);
b6453d99	98
a0105740	99	temporarily_use_uid(authctxt->pw);
a0105740	100
aa9f6a6e	101	if (problem)
aa9f6a6e	102	goto out;
bd7af13d	103
78e43412	104	problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops,
	105	&authctxt->krb5_fwd_ccache);
	106	if (problem)
	107	goto out;
	108
	109	problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache,
	110	authctxt->krb5_fwd_ccache);
	111	krb5_cc_destroy(authctxt->krb5_ctx, ccache);
	112	ccache = NULL;
	113	if (problem)
	114	goto out;
a0105740	115
12928e80	116	#else
	117	problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds,
	118	authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL);
	119	if (problem)
	120	goto out;
	121
	122	problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
	123	KRB5_NT_SRV_HST, &server);
	124	if (problem)
	125	goto out;
	126
	127	restore_uid();
	128	problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server,
	129	NULL, NULL, NULL);
	130	krb5_free_principal(authctxt->krb5_ctx, server);
	131	temporarily_use_uid(authctxt->pw);
	132	if (problem)
	133	goto out;
b6453d99	134
aff51935	135	if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user,
12928e80	136	authctxt->pw->pw_name)) {
875ec275	137	problem = -1;
12928e80	138	goto out;
aff51935	139	}
12928e80	140
937eb918	141	problem = ssh_krb5_cc_gen(authctxt->krb5_ctx, &authctxt->krb5_fwd_ccache);
12928e80	142	if (problem)
	143	goto out;
	144
	145	problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
	146	authctxt->krb5_user);
	147	if (problem)
	148	goto out;
b6453d99	149
12928e80	150	problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
	151	&creds);
	152	if (problem)
	153	goto out;
b6453d99	154	#endif
12928e80	155
aa9f6a6e	156	authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
a0105740	157
6490a5d5	158	len = strlen(authctxt->krb5_ticket_file) + 6;
	159	authctxt->krb5_ccname = xmalloc(len);
	160	snprintf(authctxt->krb5_ccname, len, "FILE:%s",
	161	authctxt->krb5_ticket_file);
	162
ef084ee2	163	#ifdef USE_PAM
	164	if (options.use_pam)
	165	do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname);
	166	#endif
	167
aa9f6a6e	168	out:
aa9f6a6e	169	restore_uid();
a0105740	170
aa9f6a6e	171	if (problem) {
78e43412	172	if (ccache)
	173	krb5_cc_destroy(authctxt->krb5_ctx, ccache);
	174
12928e80	175	if (authctxt->krb5_ctx != NULL && problem!=-1)
c12337d9	176	debug("Kerberos password authentication failed: %s",
	177	krb5_get_err_text(authctxt->krb5_ctx, problem));
	178	else
	179	debug("Kerberos password authentication failed: %d",
	180	problem);
a0105740	181
aa9f6a6e	182	krb5_cleanup_proc(authctxt);
a0105740	183
aa9f6a6e	184	if (options.kerberos_or_local_passwd)
	185	return (-1);
	186	else
	187	return (0);
	188	}
426cef74	189	return (authctxt->valid ? 1 : 0);
aa9f6a6e	190	}
	191
	192	void
2362db19	193	krb5_cleanup_proc(Authctxt *authctxt)
aa9f6a6e	194	{
aa9f6a6e	195	debug("krb5_cleanup_proc called");
	196	if (authctxt->krb5_fwd_ccache) {
	197	krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
	198	authctxt->krb5_fwd_ccache = NULL;
	199	}
	200	if (authctxt->krb5_user) {
	201	krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
	202	authctxt->krb5_user = NULL;
	203	}
aa9f6a6e	204	if (authctxt->krb5_ctx) {
	205	krb5_free_context(authctxt->krb5_ctx);
	206	authctxt->krb5_ctx = NULL;
	207	}
	208	}
	209
937eb918	210	#ifndef HEIMDAL
	211	krb5_error_code
	212	ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) {
	213	int tmpfd, ret;
	214	char ccname[40];
	215	mode_t old_umask;
	216
	217	ret = snprintf(ccname, sizeof(ccname),
	218	"FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid());
c080bed1	219	if (ret < 0 \|\| (size_t)ret >= sizeof(ccname))
6f602461	220	return ENOMEM;
937eb918	221
	222	old_umask = umask(0177);
	223	tmpfd = mkstemp(ccname + strlen("FILE:"));
	224	umask(old_umask);
	225	if (tmpfd == -1) {
	226	logit("mkstemp(): %.100s", strerror(errno));
	227	return errno;
	228	}
	229
	230	if (fchmod(tmpfd,S_IRUSR \| S_IWUSR) == -1) {
	231	logit("fchmod(): %.100s", strerror(errno));
	232	close(tmpfd);
	233	return errno;
	234	}
	235	close(tmpfd);
	236
	237	return (krb5_cc_resolve(ctx, ccname, ccache));
	238	}
	239	#endif /* !HEIMDAL */
aa9f6a6e	240	#endif /* KRB5 */