xref: /freebsd/lib/libpam/modules/pam_tacplus/pam_tacplus.c (revision 641a6cfb86023499caafe26a4d821a0b885cf00b)
1 /*-
2  * Copyright 1998 Juniper Networks, Inc.
3  * All rights reserved.
4  * Copyright (c) 2001-2003 Networks Associates Technology, Inc.
5  * All rights reserved.
6  *
7  * Portions of this software were developed for the FreeBSD Project by
8  * ThinkSec AS and NAI Labs, the Security Research Division of Network
9  * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
10  * ("CBOSS"), as part of the DARPA CHATS research program.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. The name of the author may not be used to endorse or promote
21  *    products derived from this software without specific prior written
22  *    permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include <sys/param.h>
41 
42 #include <pwd.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <syslog.h>
46 #include <taclib.h>
47 #include <unistd.h>
48 
49 #define PAM_SM_AUTH
50 
51 #include <security/pam_appl.h>
52 #include <security/pam_modules.h>
53 #include <security/pam_mod_misc.h>
54 
55 #define PAM_OPT_CONF		"conf"
56 #define PAM_OPT_TEMPLATE_USER	"template_user"
57 
58 typedef int (*set_func)(struct tac_handle *, const char *);
59 
60 static int	 do_item(pam_handle_t *, struct tac_handle *, int,
61 		    set_func, const char *);
62 static char	*get_msg(struct tac_handle *);
63 static int	 set_msg(struct tac_handle *, const char *);
64 
65 static int
66 do_item(pam_handle_t *pamh, struct tac_handle *tach, int item,
67     set_func func, const char *funcname)
68 {
69 	int retval;
70 	const void *value;
71 
72 	retval = pam_get_item(pamh, item, &value);
73 	if (retval != PAM_SUCCESS)
74 	    return retval;
75 	if (value != NULL && (*func)(tach, (const char *)value) == -1) {
76 		syslog(LOG_CRIT, "%s: %s", funcname, tac_strerror(tach));
77 		tac_close(tach);
78 		return PAM_SERVICE_ERR;
79 	}
80 	return PAM_SUCCESS;
81 }
82 
83 static char *
84 get_msg(struct tac_handle *tach)
85 {
86 	char *msg;
87 
88 	msg = tac_get_msg(tach);
89 	if (msg == NULL) {
90 		syslog(LOG_CRIT, "tac_get_msg: %s", tac_strerror(tach));
91 		tac_close(tach);
92 		return NULL;
93 	}
94 	return msg;
95 }
96 
97 static int
98 set_msg(struct tac_handle *tach, const char *msg)
99 {
100 	if (tac_set_msg(tach, msg) == -1) {
101 		syslog(LOG_CRIT, "tac_set_msg: %s", tac_strerror(tach));
102 		tac_close(tach);
103 		return -1;
104 	}
105 	return 0;
106 }
107 
108 PAM_EXTERN int
109 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
110     int argc __unused, const char *argv[] __unused)
111 {
112 	int retval;
113 	struct tac_handle *tach;
114 	const char *conf_file, *template_user;
115 
116 	conf_file = openpam_get_option(pamh, PAM_OPT_CONF);
117 	template_user = openpam_get_option(pamh, PAM_OPT_TEMPLATE_USER);
118 
119 	tach = tac_open();
120 	if (tach == NULL) {
121 		syslog(LOG_CRIT, "tac_open failed");
122 		return (PAM_SERVICE_ERR);
123 	}
124 	if (tac_config(tach, conf_file) == -1) {
125 		syslog(LOG_ALERT, "tac_config: %s", tac_strerror(tach));
126 		tac_close(tach);
127 		return (PAM_SERVICE_ERR);
128 	}
129 	if (tac_create_authen(tach, TAC_AUTHEN_LOGIN, TAC_AUTHEN_TYPE_ASCII,
130 	    TAC_AUTHEN_SVC_LOGIN) == -1) {
131 		syslog(LOG_CRIT, "tac_create_authen: %s", tac_strerror(tach));
132 		tac_close(tach);
133 		return (PAM_SERVICE_ERR);
134 	}
135 
136 	PAM_LOG("Done tac_open() ... tac_close()");
137 
138 	retval = do_item(pamh, tach, PAM_USER, tac_set_user, "tac_set_user");
139 	if (retval != PAM_SUCCESS)
140 		return (retval);
141 
142 	PAM_LOG("Done user");
143 
144 	retval = do_item(pamh, tach, PAM_TTY, tac_set_port, "tac_set_port");
145 	if (retval != PAM_SUCCESS)
146 		return (retval);
147 
148 	PAM_LOG("Done tty");
149 
150 	retval = do_item(pamh, tach, PAM_RHOST, tac_set_rem_addr,
151 	    "tac_set_rem_addr");
152 	if (retval != PAM_SUCCESS)
153 		return (retval);
154 
155 	for (;;) {
156 		char *srvr_msg;
157 		size_t msg_len;
158 		const char *user_msg;
159 		char *data_msg;
160 		int sflags;
161 		int status;
162 
163 		sflags = tac_send_authen(tach);
164 		if (sflags == -1) {
165 			syslog(LOG_CRIT, "tac_send_authen: %s",
166 			    tac_strerror(tach));
167 			tac_close(tach);
168 			return (PAM_AUTHINFO_UNAVAIL);
169 		}
170 		status = TAC_AUTHEN_STATUS(sflags);
171 		openpam_set_option(pamh, PAM_OPT_ECHO_PASS,
172 		    TAC_AUTHEN_NOECHO(sflags) ? NULL : "");
173 		switch (status) {
174 
175 		case TAC_AUTHEN_STATUS_PASS:
176 			tac_close(tach);
177 			if (template_user != NULL) {
178 				const void *item;
179 				const char *user;
180 
181 				PAM_LOG("Trying template user: %s",
182 				    template_user);
183 
184 				/*
185 				 * If the given user name doesn't exist in
186 				 * the local password database, change it
187 				 * to the value given in the "template_user"
188 				 * option.
189 				 */
190 				retval = pam_get_item(pamh, PAM_USER, &item);
191 				if (retval != PAM_SUCCESS)
192 					return (retval);
193 				user = (const char *)item;
194 				if (getpwnam(user) == NULL) {
195 					pam_set_item(pamh, PAM_USER,
196 					    template_user);
197 					PAM_LOG("Using template user");
198 				}
199 			}
200 			return (PAM_SUCCESS);
201 
202 		case TAC_AUTHEN_STATUS_FAIL:
203 			tac_close(tach);
204 			PAM_VERBOSE_ERROR("TACACS+ authentication failed");
205 			return (PAM_AUTH_ERR);
206 
207 		case TAC_AUTHEN_STATUS_GETUSER:
208 		case TAC_AUTHEN_STATUS_GETPASS:
209 			if ((srvr_msg = get_msg(tach)) == NULL)
210 				return (PAM_SERVICE_ERR);
211 			if (status == TAC_AUTHEN_STATUS_GETUSER)
212 				retval = pam_get_user(pamh, &user_msg,
213 				    *srvr_msg ? srvr_msg : NULL);
214 			else if (status == TAC_AUTHEN_STATUS_GETPASS)
215 				retval = pam_get_authtok(pamh,
216 				    PAM_AUTHTOK, &user_msg,
217 				    *srvr_msg ? srvr_msg : "Password:");
218 			free(srvr_msg);
219 			if (retval != PAM_SUCCESS) {
220 				/* XXX - send a TACACS+ abort packet */
221 				tac_close(tach);
222 				return (retval);
223 			}
224 			if (set_msg(tach, user_msg) == -1)
225 				return (PAM_SERVICE_ERR);
226 			break;
227 
228 		case TAC_AUTHEN_STATUS_GETDATA:
229 			if ((srvr_msg = get_msg(tach)) == NULL)
230 				return (PAM_SERVICE_ERR);
231 			retval = pam_prompt(pamh,
232 			    openpam_get_option(pamh, PAM_OPT_ECHO_PASS) ?
233 			    PAM_PROMPT_ECHO_ON : PAM_PROMPT_ECHO_OFF,
234 			    &data_msg, "%s", *srvr_msg ? srvr_msg : "Data:");
235 			free(srvr_msg);
236 			if (retval != PAM_SUCCESS) {
237 				/* XXX - send a TACACS+ abort packet */
238 				tac_close(tach);
239 				return (retval);
240 			}
241 			retval = set_msg(tach, data_msg);
242 			memset(data_msg, 0, strlen(data_msg));
243 			free(data_msg);
244 			if (retval == -1)
245 				return (PAM_SERVICE_ERR);
246 			break;
247 
248 		case TAC_AUTHEN_STATUS_ERROR:
249 			srvr_msg = (char *)tac_get_data(tach, &msg_len);
250 			if (srvr_msg != NULL && msg_len != 0) {
251 				syslog(LOG_CRIT, "tac_send_authen:"
252 				    " server detected error: %s", srvr_msg);
253 				free(srvr_msg);
254 			}
255 			else
256 				syslog(LOG_CRIT,
257 				    "tac_send_authen: server detected error");
258 			tac_close(tach);
259 			return (PAM_AUTHINFO_UNAVAIL);
260 			break;
261 
262 		case TAC_AUTHEN_STATUS_RESTART:
263 		case TAC_AUTHEN_STATUS_FOLLOW:
264 		default:
265 			syslog(LOG_CRIT,
266 			    "tac_send_authen: unexpected status %#x", status);
267 			tac_close(tach);
268 			return (PAM_AUTHINFO_UNAVAIL);
269 		}
270 	}
271 }
272 
273 PAM_EXTERN int
274 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
275     int argc __unused, const char *argv[] __unused)
276 {
277 
278 	return (PAM_IGNORE);
279 }
280 
281 PAM_MODULE_ENTRY("pam_tacplus");
282