[openssh.git] / auth-krb5.c

/* $OpenBSD: auth-krb5.c,v 1.19 2006/08/03 03:34:41 deraadt 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 <sys/types.h>
#include <pwd.h>
#include <stdarg.h>

#include "xmalloc.h"
#include "ssh.h"
#include "ssh1.h"
#include "packet.h"
#include "log.h"
#include "buffer.h"
#include "servconf.h"
#include "uidswap.h"
#include "key.h"
#include "hostfile.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;
	char *client, *platform_client;

	/* get platform-specific kerberos client principal name (if it exists) */
	platform_client = platform_krb5_get_principal_name(authctxt->pw->pw_name);
	client = platform_client ? platform_client : authctxt->pw->pw_name;

	temporarily_use_uid(authctxt->pw);

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

	problem = krb5_parse_name(authctxt->krb5_ctx, client,
		    &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, client)) {
		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 (platform_client != NULL)
		xfree(platform_client);

	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
31652869	1	/* $OpenBSD: auth-krb5.c,v 1.19 2006/08/03 03:34:41 deraadt 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
31652869	33	#include <sys/types.h>
	34	#include <pwd.h>
	35	#include <stdarg.h>
	36
	37	#include "xmalloc.h"
aa9f6a6e	38	#include "ssh.h"
	39	#include "ssh1.h"
	40	#include "packet.h"
aa9f6a6e	41	#include "log.h"
31652869	42	#include "buffer.h"
aa9f6a6e	43	#include "servconf.h"
aa9f6a6e	44	#include "uidswap.h"
31652869	45	#include "key.h"
31652869	46	#include "hostfile.h"
aa9f6a6e	47	#include "auth.h"
	48
	49	#ifdef KRB5
4352744e	50	#include <errno.h>
28cb0a43	51	#include <unistd.h>
28cb0a43	52	#include <string.h>
aa9f6a6e	53	#include <krb5.h>
	54
	55	extern ServerOptions options;
	56
	57	static int
	58	krb5_init(void *context)
	59	{
	60	Authctxt authctxt = (Authctxt )context;
	61	krb5_error_code problem;
a0105740	62
aa9f6a6e	63	if (authctxt->krb5_ctx == NULL) {
	64	problem = krb5_init_context(&authctxt->krb5_ctx);
	65	if (problem)
	66	return (problem);
aa9f6a6e	67	}
aa9f6a6e	68	return (0);
	69	}
	70
aa9f6a6e	71	int
	72	auth_krb5_password(Authctxt authctxt, const char password)
	73	{
12928e80	74	#ifndef HEIMDAL
	75	krb5_creds creds;
	76	krb5_principal server;
b6453d99	77	#endif
aa9f6a6e	78	krb5_error_code problem;
78e43412	79	krb5_ccache ccache = NULL;
6490a5d5	80	int len;
3bef3252	81	char client, platform_client;
	82
	83	/* get platform-specific kerberos client principal name (if it exists) */
	84	platform_client = platform_krb5_get_principal_name(authctxt->pw->pw_name);
	85	client = platform_client ? platform_client : authctxt->pw->pw_name;
a0105740	86
aa9f6a6e	87	temporarily_use_uid(authctxt->pw);
a0105740	88
aa9f6a6e	89	problem = krb5_init(authctxt);
	90	if (problem)
	91	goto out;
a0105740	92
3bef3252	93	problem = krb5_parse_name(authctxt->krb5_ctx, client,
aa9f6a6e	94	&authctxt->krb5_user);
	95	if (problem)
	96	goto out;
a0105740	97
12928e80	98	#ifdef HEIMDAL
78e43412	99	problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache);
aa9f6a6e	100	if (problem)
aa9f6a6e	101	goto out;
a0105740	102
78e43412	103	problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
78e43412	104	authctxt->krb5_user);
aa9f6a6e	105	if (problem)
aa9f6a6e	106	goto out;
a0105740	107
a0105740	108	restore_uid();
b6453d99	109
aa9f6a6e	110	problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
78e43412	111	ccache, password, 1, NULL);
b6453d99	112
a0105740	113	temporarily_use_uid(authctxt->pw);
a0105740	114
aa9f6a6e	115	if (problem)
aa9f6a6e	116	goto out;
bd7af13d	117
78e43412	118	problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops,
	119	&authctxt->krb5_fwd_ccache);
	120	if (problem)
	121	goto out;
	122
	123	problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache,
	124	authctxt->krb5_fwd_ccache);
	125	krb5_cc_destroy(authctxt->krb5_ctx, ccache);
	126	ccache = NULL;
	127	if (problem)
	128	goto out;
a0105740	129
12928e80	130	#else
	131	problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds,
	132	authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL);
	133	if (problem)
	134	goto out;
	135
	136	problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
	137	KRB5_NT_SRV_HST, &server);
	138	if (problem)
	139	goto out;
	140
	141	restore_uid();
	142	problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server,
	143	NULL, NULL, NULL);
	144	krb5_free_principal(authctxt->krb5_ctx, server);
	145	temporarily_use_uid(authctxt->pw);
	146	if (problem)
	147	goto out;
b6453d99	148
3bef3252	149	if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user, client)) {
875ec275	150	problem = -1;
12928e80	151	goto out;
aff51935	152	}
12928e80	153
937eb918	154	problem = ssh_krb5_cc_gen(authctxt->krb5_ctx, &authctxt->krb5_fwd_ccache);
12928e80	155	if (problem)
	156	goto out;
	157
	158	problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
	159	authctxt->krb5_user);
	160	if (problem)
	161	goto out;
b6453d99	162
12928e80	163	problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
	164	&creds);
	165	if (problem)
	166	goto out;
b6453d99	167	#endif
12928e80	168
aa9f6a6e	169	authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
a0105740	170
6490a5d5	171	len = strlen(authctxt->krb5_ticket_file) + 6;
	172	authctxt->krb5_ccname = xmalloc(len);
	173	snprintf(authctxt->krb5_ccname, len, "FILE:%s",
	174	authctxt->krb5_ticket_file);
	175
ef084ee2	176	#ifdef USE_PAM
	177	if (options.use_pam)
	178	do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname);
	179	#endif
	180
aa9f6a6e	181	out:
aa9f6a6e	182	restore_uid();
3bef3252	183
	184	if (platform_client != NULL)
	185	xfree(platform_client);
a0105740	186
aa9f6a6e	187	if (problem) {
78e43412	188	if (ccache)
	189	krb5_cc_destroy(authctxt->krb5_ctx, ccache);
	190
12928e80	191	if (authctxt->krb5_ctx != NULL && problem!=-1)
c12337d9	192	debug("Kerberos password authentication failed: %s",
	193	krb5_get_err_text(authctxt->krb5_ctx, problem));
	194	else
	195	debug("Kerberos password authentication failed: %d",
	196	problem);
a0105740	197
aa9f6a6e	198	krb5_cleanup_proc(authctxt);
a0105740	199
aa9f6a6e	200	if (options.kerberos_or_local_passwd)
	201	return (-1);
	202	else
	203	return (0);
	204	}
426cef74	205	return (authctxt->valid ? 1 : 0);
aa9f6a6e	206	}
	207
	208	void
2362db19	209	krb5_cleanup_proc(Authctxt *authctxt)
aa9f6a6e	210	{
aa9f6a6e	211	debug("krb5_cleanup_proc called");
	212	if (authctxt->krb5_fwd_ccache) {
	213	krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
	214	authctxt->krb5_fwd_ccache = NULL;
	215	}
	216	if (authctxt->krb5_user) {
	217	krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
	218	authctxt->krb5_user = NULL;
	219	}
aa9f6a6e	220	if (authctxt->krb5_ctx) {
	221	krb5_free_context(authctxt->krb5_ctx);
	222	authctxt->krb5_ctx = NULL;
	223	}
	224	}
	225
937eb918	226	#ifndef HEIMDAL
	227	krb5_error_code
	228	ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) {
	229	int tmpfd, ret;
	230	char ccname[40];
	231	mode_t old_umask;
	232
	233	ret = snprintf(ccname, sizeof(ccname),
	234	"FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid());
c080bed1	235	if (ret < 0 \|\| (size_t)ret >= sizeof(ccname))
6f602461	236	return ENOMEM;
937eb918	237
	238	old_umask = umask(0177);
	239	tmpfd = mkstemp(ccname + strlen("FILE:"));
	240	umask(old_umask);
	241	if (tmpfd == -1) {
	242	logit("mkstemp(): %.100s", strerror(errno));
	243	return errno;
	244	}
	245
	246	if (fchmod(tmpfd,S_IRUSR \| S_IWUSR) == -1) {
	247	logit("fchmod(): %.100s", strerror(errno));
	248	close(tmpfd);
	249	return errno;
	250	}
	251	close(tmpfd);
	252
	253	return (krb5_cc_resolve(ctx, ccname, ccache));
	254	}
	255	#endif /* !HEIMDAL */
aa9f6a6e	256	#endif /* KRB5 */