xref: /freebsd/lib/libpam/modules/pam_tacplus/pam_tacplus.c (revision b52b9d56d4e96089873a75f9e29062eec19fabba)
1 /*-
2  * Copyright 1998 Juniper Networks, Inc.
3  * All rights reserved.
4  * Copyright (c) 2001,2002 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 enum {
56 	PAM_OPT_CONF = PAM_OPT_STD_MAX,
57 	PAM_OPT_TEMPLATE_USER
58 };
59 
60 static struct opttab other_options[] = {
61 	{ "conf",		PAM_OPT_CONF },
62 	{ "template_user",	PAM_OPT_TEMPLATE_USER },
63 	{ NULL, 0 }
64 };
65 
66 typedef int (*set_func)(struct tac_handle *, const char *);
67 
68 static int	 do_item(pam_handle_t *, struct tac_handle *, int,
69 		    set_func, const char *);
70 static char	*get_msg(struct tac_handle *);
71 static int	 set_msg(struct tac_handle *, const char *);
72 
73 static int
74 do_item(pam_handle_t *pamh, struct tac_handle *tach, int item,
75     set_func func, const char *funcname)
76 {
77 	int retval;
78 	const void *value;
79 
80 	retval = pam_get_item(pamh, item, &value);
81 	if (retval != PAM_SUCCESS)
82 	    return retval;
83 	if (value != NULL && (*func)(tach, (const char *)value) == -1) {
84 		syslog(LOG_CRIT, "%s: %s", funcname, tac_strerror(tach));
85 		tac_close(tach);
86 		return PAM_SERVICE_ERR;
87 	}
88 	return PAM_SUCCESS;
89 }
90 
91 static char *
92 get_msg(struct tac_handle *tach)
93 {
94 	char *msg;
95 
96 	msg = tac_get_msg(tach);
97 	if (msg == NULL) {
98 		syslog(LOG_CRIT, "tac_get_msg: %s", tac_strerror(tach));
99 		tac_close(tach);
100 		return NULL;
101 	}
102 	return msg;
103 }
104 
105 static int
106 set_msg(struct tac_handle *tach, const char *msg)
107 {
108 	if (tac_set_msg(tach, msg) == -1) {
109 		syslog(LOG_CRIT, "tac_set_msg: %s", tac_strerror(tach));
110 		tac_close(tach);
111 		return -1;
112 	}
113 	return 0;
114 }
115 
116 PAM_EXTERN int
117 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
118     int argc, const char *argv[])
119 {
120 	struct options options;
121 	int retval;
122 	struct tac_handle *tach;
123 	char *conf_file;
124 	char *template_user;
125 
126 	pam_std_option(&options, other_options, argc, argv);
127 
128 	PAM_LOG("Options processed");
129 
130 	conf_file = NULL;
131 	pam_test_option(&options, PAM_OPT_CONF, &conf_file);
132 	template_user = NULL;
133 	pam_test_option(&options, PAM_OPT_TEMPLATE_USER, &template_user);
134 
135 	tach = tac_open();
136 	if (tach == NULL) {
137 		syslog(LOG_CRIT, "tac_open failed");
138 		return (PAM_SERVICE_ERR);
139 	}
140 	if (tac_config(tach, conf_file) == -1) {
141 		syslog(LOG_ALERT, "tac_config: %s", tac_strerror(tach));
142 		tac_close(tach);
143 		return (PAM_SERVICE_ERR);
144 	}
145 	if (tac_create_authen(tach, TAC_AUTHEN_LOGIN, TAC_AUTHEN_TYPE_ASCII,
146 	    TAC_AUTHEN_SVC_LOGIN) == -1) {
147 		syslog(LOG_CRIT, "tac_create_authen: %s", tac_strerror(tach));
148 		tac_close(tach);
149 		return (PAM_SERVICE_ERR);
150 	}
151 
152 	PAM_LOG("Done tac_open() ... tac_close()");
153 
154 	retval = do_item(pamh, tach, PAM_USER, tac_set_user, "tac_set_user");
155 	if (retval != PAM_SUCCESS)
156 		return (retval);
157 
158 	PAM_LOG("Done user");
159 
160 	retval = do_item(pamh, tach, PAM_TTY, tac_set_port, "tac_set_port");
161 	if (retval != PAM_SUCCESS)
162 		return (retval);
163 
164 	PAM_LOG("Done tty");
165 
166 	retval = do_item(pamh, tach, PAM_RHOST, tac_set_rem_addr,
167 	    "tac_set_rem_addr");
168 	if (retval != PAM_SUCCESS)
169 		return (retval);
170 
171 	for (;;) {
172 		char *srvr_msg;
173 		size_t msg_len;
174 		const char *user_msg;
175 		char *data_msg;
176 		int sflags;
177 		int status;
178 
179 		sflags = tac_send_authen(tach);
180 		if (sflags == -1) {
181 			syslog(LOG_CRIT, "tac_send_authen: %s",
182 			    tac_strerror(tach));
183 			tac_close(tach);
184 			return (PAM_AUTHINFO_UNAVAIL);
185 		}
186 		status = TAC_AUTHEN_STATUS(sflags);
187 		if (!TAC_AUTHEN_NOECHO(sflags))
188 			pam_set_option(&options, PAM_OPT_ECHO_PASS);
189 		switch (status) {
190 
191 		case TAC_AUTHEN_STATUS_PASS:
192 			tac_close(tach);
193 			if (template_user != NULL) {
194 				const void *item;
195 				const char *user;
196 
197 				PAM_LOG("Trying template user: %s",
198 				    template_user);
199 
200 				/*
201 				 * If the given user name doesn't exist in
202 				 * the local password database, change it
203 				 * to the value given in the "template_user"
204 				 * option.
205 				 */
206 				retval = pam_get_item(pamh, PAM_USER, &item);
207 				if (retval != PAM_SUCCESS)
208 					return (retval);
209 				user = (const char *)item;
210 				if (getpwnam(user) == NULL) {
211 					pam_set_item(pamh, PAM_USER,
212 					    template_user);
213 					PAM_LOG("Using template user");
214 				}
215 			}
216 			return (PAM_SUCCESS);
217 
218 		case TAC_AUTHEN_STATUS_FAIL:
219 			tac_close(tach);
220 			PAM_VERBOSE_ERROR("TACACS+ authentication failed");
221 			return (PAM_AUTH_ERR);
222 
223 		case TAC_AUTHEN_STATUS_GETUSER:
224 		case TAC_AUTHEN_STATUS_GETPASS:
225 			if ((srvr_msg = get_msg(tach)) == NULL)
226 				return (PAM_SERVICE_ERR);
227 			if (status == TAC_AUTHEN_STATUS_GETUSER)
228 				retval = pam_get_user(pamh, &user_msg,
229 				    *srvr_msg ? srvr_msg : NULL);
230 			else if (status == TAC_AUTHEN_STATUS_GETPASS)
231 				retval = pam_get_authtok(pamh,
232 				    PAM_AUTHTOK, &user_msg,
233 				    *srvr_msg ? srvr_msg : "Password:");
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 			if (set_msg(tach, user_msg) == -1)
241 				return (PAM_SERVICE_ERR);
242 			break;
243 
244 		case TAC_AUTHEN_STATUS_GETDATA:
245 			if ((srvr_msg = get_msg(tach)) == NULL)
246 				return (PAM_SERVICE_ERR);
247 			retval = pam_prompt(pamh,
248 			    pam_test_option(&options, PAM_OPT_ECHO_PASS, NULL)
249 				? PAM_PROMPT_ECHO_ON : PAM_PROMPT_ECHO_OFF,
250 			    &data_msg, "%s", *srvr_msg ? srvr_msg : "Data:");
251 			free(srvr_msg);
252 			if (retval != PAM_SUCCESS) {
253 				/* XXX - send a TACACS+ abort packet */
254 				tac_close(tach);
255 				return (retval);
256 			}
257 			retval = set_msg(tach, data_msg);
258 			memset(data_msg, 0, strlen(data_msg));
259 			free(data_msg);
260 			if (retval == -1)
261 				return (PAM_SERVICE_ERR);
262 			break;
263 
264 		case TAC_AUTHEN_STATUS_ERROR:
265 			srvr_msg = (char *)tac_get_data(tach, &msg_len);
266 			if (srvr_msg != NULL && msg_len != 0) {
267 				syslog(LOG_CRIT, "tac_send_authen:"
268 				    " server detected error: %s", srvr_msg);
269 				free(srvr_msg);
270 			}
271 			else
272 				syslog(LOG_CRIT,
273 				    "tac_send_authen: server detected error");
274 			tac_close(tach);
275 			return (PAM_AUTHINFO_UNAVAIL);
276 			break;
277 
278 		case TAC_AUTHEN_STATUS_RESTART:
279 		case TAC_AUTHEN_STATUS_FOLLOW:
280 		default:
281 			syslog(LOG_CRIT,
282 			    "tac_send_authen: unexpected status %#x", status);
283 			tac_close(tach);
284 			return (PAM_AUTHINFO_UNAVAIL);
285 		}
286 	}
287 }
288 
289 PAM_EXTERN int
290 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
291     int argc __unused, const char *argv[] __unused)
292 {
293 
294 	return (PAM_IGNORE);
295 }
296 
297 PAM_MODULE_ENTRY("pam_tacplus");
298