pam_tacplus.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright 1998 Juniper Networks, Inc.
5 * All rights reserved.
6 * Copyright (c) 2001-2003 Networks Associates Technology, Inc.
7 * All rights reserved.
8 *
9 * Portions of this software were developed for the FreeBSD Project by
10 * ThinkSec AS and NAI Labs, the Security Research Division of Network
11 * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
12 * ("CBOSS"), as part of the DARPA CHATS research program.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 *    notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 *    notice, this list of conditions and the following disclaimer in the
21 *    documentation and/or other materials provided with the distribution.
22 * 3. The name of the author may not be used to endorse or promote
23 *    products derived from this software without specific prior written
24 *    permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 */
38
39#include <sys/cdefs.h>
40__FBSDID("$FreeBSD: stable/11/lib/libpam/modules/pam_tacplus/pam_tacplus.c 330897 2018-03-14 03:19:51Z eadler $");
41
42#include <sys/param.h>
43
44#include <pwd.h>
45#include <stdlib.h>
46#include <string.h>
47#include <syslog.h>
48#include <taclib.h>
49#include <unistd.h>
50
51#define PAM_SM_AUTH
52
53#include <security/pam_appl.h>
54#include <security/pam_modules.h>
55#include <security/pam_mod_misc.h>
56
57#define PAM_OPT_CONF		"conf"
58#define PAM_OPT_TEMPLATE_USER	"template_user"
59
60typedef int (*set_func)(struct tac_handle *, const char *);
61
62static int	 do_item(pam_handle_t *, struct tac_handle *, int,
63		    set_func, const char *);
64static char	*get_msg(struct tac_handle *);
65static int	 set_msg(struct tac_handle *, const char *);
66
67static int
68do_item(pam_handle_t *pamh, struct tac_handle *tach, int item,
69    set_func func, const char *funcname)
70{
71	int retval;
72	const void *value;
73
74	retval = pam_get_item(pamh, item, &value);
75	if (retval != PAM_SUCCESS)
76	    return retval;
77	if (value != NULL && (*func)(tach, (const char *)value) == -1) {
78		syslog(LOG_CRIT, "%s: %s", funcname, tac_strerror(tach));
79		tac_close(tach);
80		return PAM_SERVICE_ERR;
81	}
82	return PAM_SUCCESS;
83}
84
85static char *
86get_msg(struct tac_handle *tach)
87{
88	char *msg;
89
90	msg = tac_get_msg(tach);
91	if (msg == NULL) {
92		syslog(LOG_CRIT, "tac_get_msg: %s", tac_strerror(tach));
93		tac_close(tach);
94		return NULL;
95	}
96	return msg;
97}
98
99static int
100set_msg(struct tac_handle *tach, const char *msg)
101{
102	if (tac_set_msg(tach, msg) == -1) {
103		syslog(LOG_CRIT, "tac_set_msg: %s", tac_strerror(tach));
104		tac_close(tach);
105		return -1;
106	}
107	return 0;
108}
109
110PAM_EXTERN int
111pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
112    int argc __unused, const char *argv[] __unused)
113{
114	int retval;
115	struct tac_handle *tach;
116	const char *conf_file, *template_user;
117
118	conf_file = openpam_get_option(pamh, PAM_OPT_CONF);
119	template_user = openpam_get_option(pamh, PAM_OPT_TEMPLATE_USER);
120
121	tach = tac_open();
122	if (tach == NULL) {
123		syslog(LOG_CRIT, "tac_open failed");
124		return (PAM_SERVICE_ERR);
125	}
126	if (tac_config(tach, conf_file) == -1) {
127		syslog(LOG_ALERT, "tac_config: %s", tac_strerror(tach));
128		tac_close(tach);
129		return (PAM_SERVICE_ERR);
130	}
131	if (tac_create_authen(tach, TAC_AUTHEN_LOGIN, TAC_AUTHEN_TYPE_ASCII,
132	    TAC_AUTHEN_SVC_LOGIN) == -1) {
133		syslog(LOG_CRIT, "tac_create_authen: %s", tac_strerror(tach));
134		tac_close(tach);
135		return (PAM_SERVICE_ERR);
136	}
137
138	PAM_LOG("Done tac_open() ... tac_close()");
139
140	retval = do_item(pamh, tach, PAM_USER, tac_set_user, "tac_set_user");
141	if (retval != PAM_SUCCESS)
142		return (retval);
143
144	PAM_LOG("Done user");
145
146	retval = do_item(pamh, tach, PAM_TTY, tac_set_port, "tac_set_port");
147	if (retval != PAM_SUCCESS)
148		return (retval);
149
150	PAM_LOG("Done tty");
151
152	retval = do_item(pamh, tach, PAM_RHOST, tac_set_rem_addr,
153	    "tac_set_rem_addr");
154	if (retval != PAM_SUCCESS)
155		return (retval);
156
157	for (;;) {
158		char *srvr_msg;
159		size_t msg_len;
160		const char *user_msg;
161		char *data_msg;
162		int sflags;
163		int status;
164
165		sflags = tac_send_authen(tach);
166		if (sflags == -1) {
167			syslog(LOG_CRIT, "tac_send_authen: %s",
168			    tac_strerror(tach));
169			tac_close(tach);
170			return (PAM_AUTHINFO_UNAVAIL);
171		}
172		status = TAC_AUTHEN_STATUS(sflags);
173		openpam_set_option(pamh, PAM_OPT_ECHO_PASS,
174		    TAC_AUTHEN_NOECHO(sflags) ? NULL : "");
175		switch (status) {
176
177		case TAC_AUTHEN_STATUS_PASS:
178			tac_close(tach);
179			if (template_user != NULL) {
180				const void *item;
181				const char *user;
182
183				PAM_LOG("Trying template user: %s",
184				    template_user);
185
186				/*
187				 * If the given user name doesn't exist in
188				 * the local password database, change it
189				 * to the value given in the "template_user"
190				 * option.
191				 */
192				retval = pam_get_item(pamh, PAM_USER, &item);
193				if (retval != PAM_SUCCESS)
194					return (retval);
195				user = (const char *)item;
196				if (getpwnam(user) == NULL) {
197					pam_set_item(pamh, PAM_USER,
198					    template_user);
199					PAM_LOG("Using template user");
200				}
201			}
202			return (PAM_SUCCESS);
203
204		case TAC_AUTHEN_STATUS_FAIL:
205			tac_close(tach);
206			PAM_VERBOSE_ERROR("TACACS+ authentication failed");
207			return (PAM_AUTH_ERR);
208
209		case TAC_AUTHEN_STATUS_GETUSER:
210		case TAC_AUTHEN_STATUS_GETPASS:
211			if ((srvr_msg = get_msg(tach)) == NULL)
212				return (PAM_SERVICE_ERR);
213			if (status == TAC_AUTHEN_STATUS_GETUSER)
214				retval = pam_get_user(pamh, &user_msg,
215				    *srvr_msg ? srvr_msg : NULL);
216			else if (status == TAC_AUTHEN_STATUS_GETPASS)
217				retval = pam_get_authtok(pamh,
218				    PAM_AUTHTOK, &user_msg,
219				    *srvr_msg ? srvr_msg : "Password:");
220			free(srvr_msg);
221			if (retval != PAM_SUCCESS) {
222				/* XXX - send a TACACS+ abort packet */
223				tac_close(tach);
224				return (retval);
225			}
226			if (set_msg(tach, user_msg) == -1)
227				return (PAM_SERVICE_ERR);
228			break;
229
230		case TAC_AUTHEN_STATUS_GETDATA:
231			if ((srvr_msg = get_msg(tach)) == NULL)
232				return (PAM_SERVICE_ERR);
233			retval = pam_prompt(pamh,
234			    openpam_get_option(pamh, PAM_OPT_ECHO_PASS) ?
235			    PAM_PROMPT_ECHO_ON : PAM_PROMPT_ECHO_OFF,
236			    &data_msg, "%s", *srvr_msg ? srvr_msg : "Data:");
237			free(srvr_msg);
238			if (retval != PAM_SUCCESS) {
239				/* XXX - send a TACACS+ abort packet */
240				tac_close(tach);
241				return (retval);
242			}
243			retval = set_msg(tach, data_msg);
244			memset(data_msg, 0, strlen(data_msg));
245			free(data_msg);
246			if (retval == -1)
247				return (PAM_SERVICE_ERR);
248			break;
249
250		case TAC_AUTHEN_STATUS_ERROR:
251			srvr_msg = (char *)tac_get_data(tach, &msg_len);
252			if (srvr_msg != NULL && msg_len != 0) {
253				syslog(LOG_CRIT, "tac_send_authen:"
254				    " server detected error: %s", srvr_msg);
255				free(srvr_msg);
256			}
257			else
258				syslog(LOG_CRIT,
259				    "tac_send_authen: server detected error");
260			tac_close(tach);
261			return (PAM_AUTHINFO_UNAVAIL);
262			break;
263
264		case TAC_AUTHEN_STATUS_RESTART:
265		case TAC_AUTHEN_STATUS_FOLLOW:
266		default:
267			syslog(LOG_CRIT,
268			    "tac_send_authen: unexpected status %#x", status);
269			tac_close(tach);
270			return (PAM_AUTHINFO_UNAVAIL);
271		}
272	}
273}
274
275PAM_EXTERN int
276pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
277    int argc __unused, const char *argv[] __unused)
278{
279
280	return (PAM_IGNORE);
281}
282
283PAM_MODULE_ENTRY("pam_tacplus");
284