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/param.h>
40
41#include <pwd.h>
42#include <stdlib.h>
43#include <string.h>
44#include <syslog.h>
45#include <taclib.h>
46#include <unistd.h>
47
48#define PAM_SM_AUTH
49
50#include <security/pam_appl.h>
51#include <security/pam_modules.h>
52#include <security/pam_mod_misc.h>
53
54#define PAM_OPT_CONF		"conf"
55#define PAM_OPT_TEMPLATE_USER	"template_user"
56
57typedef int (*set_func)(struct tac_handle *, const char *);
58
59static int	 do_item(pam_handle_t *, struct tac_handle *, int,
60		    set_func, const char *);
61static char	*get_msg(struct tac_handle *);
62static int	 set_msg(struct tac_handle *, const char *);
63
64static int
65do_item(pam_handle_t *pamh, struct tac_handle *tach, int item,
66    set_func func, const char *funcname)
67{
68	int retval;
69	const void *value;
70
71	retval = pam_get_item(pamh, item, &value);
72	if (retval != PAM_SUCCESS)
73	    return retval;
74	if (value != NULL && (*func)(tach, (const char *)value) == -1) {
75		syslog(LOG_CRIT, "%s: %s", funcname, tac_strerror(tach));
76		tac_close(tach);
77		return PAM_SERVICE_ERR;
78	}
79	return PAM_SUCCESS;
80}
81
82static char *
83get_msg(struct tac_handle *tach)
84{
85	char *msg;
86
87	msg = tac_get_msg(tach);
88	if (msg == NULL) {
89		syslog(LOG_CRIT, "tac_get_msg: %s", tac_strerror(tach));
90		tac_close(tach);
91		return NULL;
92	}
93	return msg;
94}
95
96static int
97set_msg(struct tac_handle *tach, const char *msg)
98{
99	if (tac_set_msg(tach, msg) == -1) {
100		syslog(LOG_CRIT, "tac_set_msg: %s", tac_strerror(tach));
101		tac_close(tach);
102		return -1;
103	}
104	return 0;
105}
106
107PAM_EXTERN int
108pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
109    int argc __unused, const char *argv[] __unused)
110{
111	int retval;
112	struct tac_handle *tach;
113	const char *conf_file, *template_user;
114
115	conf_file = openpam_get_option(pamh, PAM_OPT_CONF);
116	template_user = openpam_get_option(pamh, PAM_OPT_TEMPLATE_USER);
117
118	tach = tac_open();
119	if (tach == NULL) {
120		syslog(LOG_CRIT, "tac_open failed");
121		return (PAM_SERVICE_ERR);
122	}
123	if (tac_config(tach, conf_file) == -1) {
124		syslog(LOG_ALERT, "tac_config: %s", tac_strerror(tach));
125		tac_close(tach);
126		return (PAM_SERVICE_ERR);
127	}
128	if (tac_create_authen(tach, TAC_AUTHEN_LOGIN, TAC_AUTHEN_TYPE_ASCII,
129	    TAC_AUTHEN_SVC_LOGIN) == -1) {
130		syslog(LOG_CRIT, "tac_create_authen: %s", tac_strerror(tach));
131		tac_close(tach);
132		return (PAM_SERVICE_ERR);
133	}
134
135	PAM_LOG("Done tac_open() ... tac_close()");
136
137	retval = do_item(pamh, tach, PAM_USER, tac_set_user, "tac_set_user");
138	if (retval != PAM_SUCCESS)
139		return (retval);
140
141	PAM_LOG("Done user");
142
143	retval = do_item(pamh, tach, PAM_TTY, tac_set_port, "tac_set_port");
144	if (retval != PAM_SUCCESS)
145		return (retval);
146
147	PAM_LOG("Done tty");
148
149	retval = do_item(pamh, tach, PAM_RHOST, tac_set_rem_addr,
150	    "tac_set_rem_addr");
151	if (retval != PAM_SUCCESS)
152		return (retval);
153
154	for (;;) {
155		char *srvr_msg;
156		size_t msg_len;
157		const char *user_msg;
158		char *data_msg;
159		int sflags;
160		int status;
161
162		sflags = tac_send_authen(tach);
163		if (sflags == -1) {
164			syslog(LOG_CRIT, "tac_send_authen: %s",
165			    tac_strerror(tach));
166			tac_close(tach);
167			return (PAM_AUTHINFO_UNAVAIL);
168		}
169		status = TAC_AUTHEN_STATUS(sflags);
170		openpam_set_option(pamh, PAM_OPT_ECHO_PASS,
171		    TAC_AUTHEN_NOECHO(sflags) ? NULL : "");
172		switch (status) {
173
174		case TAC_AUTHEN_STATUS_PASS:
175			tac_close(tach);
176			if (template_user != NULL) {
177				const void *item;
178				const char *user;
179
180				PAM_LOG("Trying template user: %s",
181				    template_user);
182
183				/*
184				 * If the given user name doesn't exist in
185				 * the local password database, change it
186				 * to the value given in the "template_user"
187				 * option.
188				 */
189				retval = pam_get_item(pamh, PAM_USER, &item);
190				if (retval != PAM_SUCCESS)
191					return (retval);
192				user = (const char *)item;
193				if (getpwnam(user) == NULL) {
194					pam_set_item(pamh, PAM_USER,
195					    template_user);
196					PAM_LOG("Using template user");
197				}
198			}
199			return (PAM_SUCCESS);
200
201		case TAC_AUTHEN_STATUS_FAIL:
202			tac_close(tach);
203			PAM_VERBOSE_ERROR("TACACS+ authentication failed");
204			return (PAM_AUTH_ERR);
205
206		case TAC_AUTHEN_STATUS_GETUSER:
207		case TAC_AUTHEN_STATUS_GETPASS:
208			if ((srvr_msg = get_msg(tach)) == NULL)
209				return (PAM_SERVICE_ERR);
210			if (status == TAC_AUTHEN_STATUS_GETUSER)
211				retval = pam_get_user(pamh, &user_msg,
212				    *srvr_msg ? srvr_msg : NULL);
213			else if (status == TAC_AUTHEN_STATUS_GETPASS)
214				retval = pam_get_authtok(pamh,
215				    PAM_AUTHTOK, &user_msg,
216				    *srvr_msg ? srvr_msg : "Password:");
217			free(srvr_msg);
218			if (retval != PAM_SUCCESS) {
219				/* XXX - send a TACACS+ abort packet */
220				tac_close(tach);
221				return (retval);
222			}
223			if (set_msg(tach, user_msg) == -1)
224				return (PAM_SERVICE_ERR);
225			break;
226
227		case TAC_AUTHEN_STATUS_GETDATA:
228			if ((srvr_msg = get_msg(tach)) == NULL)
229				return (PAM_SERVICE_ERR);
230			retval = pam_prompt(pamh,
231			    openpam_get_option(pamh, PAM_OPT_ECHO_PASS) ?
232			    PAM_PROMPT_ECHO_ON : PAM_PROMPT_ECHO_OFF,
233			    &data_msg, "%s", *srvr_msg ? srvr_msg : "Data:");
234			free(srvr_msg);
235			if (retval != PAM_SUCCESS) {
236				/* XXX - send a TACACS+ abort packet */
237				tac_close(tach);
238				return (retval);
239			}
240			retval = set_msg(tach, data_msg);
241			memset(data_msg, 0, strlen(data_msg));
242			free(data_msg);
243			if (retval == -1)
244				return (PAM_SERVICE_ERR);
245			break;
246
247		case TAC_AUTHEN_STATUS_ERROR:
248			srvr_msg = (char *)tac_get_data(tach, &msg_len);
249			if (srvr_msg != NULL && msg_len != 0) {
250				syslog(LOG_CRIT, "tac_send_authen:"
251				    " server detected error: %s", srvr_msg);
252				free(srvr_msg);
253			}
254			else
255				syslog(LOG_CRIT,
256				    "tac_send_authen: server detected error");
257			tac_close(tach);
258			return (PAM_AUTHINFO_UNAVAIL);
259			break;
260
261		case TAC_AUTHEN_STATUS_RESTART:
262		case TAC_AUTHEN_STATUS_FOLLOW:
263		default:
264			syslog(LOG_CRIT,
265			    "tac_send_authen: unexpected status %#x", status);
266			tac_close(tach);
267			return (PAM_AUTHINFO_UNAVAIL);
268		}
269	}
270}
271
272PAM_EXTERN int
273pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
274    int argc __unused, const char *argv[] __unused)
275{
276
277	return (PAM_IGNORE);
278}
279
280PAM_MODULE_ENTRY("pam_tacplus");
281