[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 <unistd.h>
#include <string.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>
28cb0a43	44	#include <unistd.h>
28cb0a43	45	#include <string.h>
aa9f6a6e	46	#include <krb5.h>
	47
	48	extern ServerOptions options;
	49
	50	static int
	51	krb5_init(void *context)
	52	{
	53	Authctxt authctxt = (Authctxt )context;
	54	krb5_error_code problem;
a0105740	55
aa9f6a6e	56	if (authctxt->krb5_ctx == NULL) {
	57	problem = krb5_init_context(&authctxt->krb5_ctx);
	58	if (problem)
	59	return (problem);
aa9f6a6e	60	}
aa9f6a6e	61	return (0);
	62	}
	63
aa9f6a6e	64	int
	65	auth_krb5_password(Authctxt authctxt, const char password)
	66	{
12928e80	67	#ifndef HEIMDAL
	68	krb5_creds creds;
	69	krb5_principal server;
b6453d99	70	#endif
aa9f6a6e	71	krb5_error_code problem;
78e43412	72	krb5_ccache ccache = NULL;
6490a5d5	73	int len;
a0105740	74
aa9f6a6e	75	temporarily_use_uid(authctxt->pw);
a0105740	76
aa9f6a6e	77	problem = krb5_init(authctxt);
	78	if (problem)
	79	goto out;
a0105740	80
aa9f6a6e	81	problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name,
	82	&authctxt->krb5_user);
	83	if (problem)
	84	goto out;
a0105740	85
12928e80	86	#ifdef HEIMDAL
78e43412	87	problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache);
aa9f6a6e	88	if (problem)
aa9f6a6e	89	goto out;
a0105740	90
78e43412	91	problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
78e43412	92	authctxt->krb5_user);
aa9f6a6e	93	if (problem)
aa9f6a6e	94	goto out;
a0105740	95
a0105740	96	restore_uid();
b6453d99	97
aa9f6a6e	98	problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
78e43412	99	ccache, password, 1, NULL);
b6453d99	100
a0105740	101	temporarily_use_uid(authctxt->pw);
a0105740	102
aa9f6a6e	103	if (problem)
aa9f6a6e	104	goto out;
bd7af13d	105
78e43412	106	problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops,
	107	&authctxt->krb5_fwd_ccache);
	108	if (problem)
	109	goto out;
	110
	111	problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache,
	112	authctxt->krb5_fwd_ccache);
	113	krb5_cc_destroy(authctxt->krb5_ctx, ccache);
	114	ccache = NULL;
	115	if (problem)
	116	goto out;
a0105740	117
12928e80	118	#else
	119	problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds,
	120	authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL);
	121	if (problem)
	122	goto out;
	123
	124	problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
	125	KRB5_NT_SRV_HST, &server);
	126	if (problem)
	127	goto out;
	128
	129	restore_uid();
	130	problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server,
	131	NULL, NULL, NULL);
	132	krb5_free_principal(authctxt->krb5_ctx, server);
	133	temporarily_use_uid(authctxt->pw);
	134	if (problem)
	135	goto out;
b6453d99	136
aff51935	137	if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user,
12928e80	138	authctxt->pw->pw_name)) {
875ec275	139	problem = -1;
12928e80	140	goto out;
aff51935	141	}
12928e80	142
937eb918	143	problem = ssh_krb5_cc_gen(authctxt->krb5_ctx, &authctxt->krb5_fwd_ccache);
12928e80	144	if (problem)
	145	goto out;
	146
	147	problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
	148	authctxt->krb5_user);
	149	if (problem)
	150	goto out;
b6453d99	151
12928e80	152	problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
	153	&creds);
	154	if (problem)
	155	goto out;
b6453d99	156	#endif
12928e80	157
aa9f6a6e	158	authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
a0105740	159
6490a5d5	160	len = strlen(authctxt->krb5_ticket_file) + 6;
	161	authctxt->krb5_ccname = xmalloc(len);
	162	snprintf(authctxt->krb5_ccname, len, "FILE:%s",
	163	authctxt->krb5_ticket_file);
	164
ef084ee2	165	#ifdef USE_PAM
	166	if (options.use_pam)
	167	do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname);
	168	#endif
	169
aa9f6a6e	170	out:
aa9f6a6e	171	restore_uid();
a0105740	172
aa9f6a6e	173	if (problem) {
78e43412	174	if (ccache)
	175	krb5_cc_destroy(authctxt->krb5_ctx, ccache);
	176
12928e80	177	if (authctxt->krb5_ctx != NULL && problem!=-1)
c12337d9	178	debug("Kerberos password authentication failed: %s",
	179	krb5_get_err_text(authctxt->krb5_ctx, problem));
	180	else
	181	debug("Kerberos password authentication failed: %d",
	182	problem);
a0105740	183
aa9f6a6e	184	krb5_cleanup_proc(authctxt);
a0105740	185
aa9f6a6e	186	if (options.kerberos_or_local_passwd)
	187	return (-1);
	188	else
	189	return (0);
	190	}
426cef74	191	return (authctxt->valid ? 1 : 0);
aa9f6a6e	192	}
	193
	194	void
2362db19	195	krb5_cleanup_proc(Authctxt *authctxt)
aa9f6a6e	196	{
aa9f6a6e	197	debug("krb5_cleanup_proc called");
	198	if (authctxt->krb5_fwd_ccache) {
	199	krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
	200	authctxt->krb5_fwd_ccache = NULL;
	201	}
	202	if (authctxt->krb5_user) {
	203	krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
	204	authctxt->krb5_user = NULL;
	205	}
aa9f6a6e	206	if (authctxt->krb5_ctx) {
	207	krb5_free_context(authctxt->krb5_ctx);
	208	authctxt->krb5_ctx = NULL;
	209	}
	210	}
	211
937eb918	212	#ifndef HEIMDAL
	213	krb5_error_code
	214	ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) {
	215	int tmpfd, ret;
	216	char ccname[40];
	217	mode_t old_umask;
	218
	219	ret = snprintf(ccname, sizeof(ccname),
	220	"FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid());
c080bed1	221	if (ret < 0 \|\| (size_t)ret >= sizeof(ccname))
6f602461	222	return ENOMEM;
937eb918	223
	224	old_umask = umask(0177);
	225	tmpfd = mkstemp(ccname + strlen("FILE:"));
	226	umask(old_umask);
	227	if (tmpfd == -1) {
	228	logit("mkstemp(): %.100s", strerror(errno));
	229	return errno;
	230	}
	231
	232	if (fchmod(tmpfd,S_IRUSR \| S_IWUSR) == -1) {
	233	logit("fchmod(): %.100s", strerror(errno));
	234	close(tmpfd);
	235	return errno;
	236	}
	237	close(tmpfd);
	238
	239	return (krb5_cc_resolve(ctx, ccname, ccache));
	240	}
	241	#endif /* !HEIMDAL */
aa9f6a6e	242	#endif /* KRB5 */