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 #include <sys/types.h>
42 #include <sys/socket.h>
43 #include <netdb.h>
44 #include <pwd.h>
45 #include <radlib.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <syslog.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 #define PAM_OPT_NAS_ID		"nas_id"
60 #define PAM_OPT_NAS_IPADDR	"nas_ipaddr"
61 
62 #define	MAX_CHALLENGE_MSGS	10
63 #define	PASSWORD_PROMPT		"RADIUS Password:"
64 
65 static int	 build_access_request(struct rad_handle *, const char *,
66 		    const char *, const char *, const char *, const void *,
67 		    size_t);
68 static int	 do_accept(pam_handle_t *, struct rad_handle *);
69 static int	 do_challenge(pam_handle_t *, struct rad_handle *,
70 		    const char *);
71 
72 /*
73  * Construct an access request, but don't send it.  Returns 0 on success,
74  * -1 on failure.
75  */
76 static int
77 build_access_request(struct rad_handle *radh, const char *user,
78     const char *pass, const char *nas_id, const char *nas_ipaddr,
79     const void *state, size_t state_len)
80 {
81 	int error;
82 	char host[MAXHOSTNAMELEN];
83 	struct sockaddr_in *haddr;
84 	struct addrinfo hints;
85 	struct addrinfo *res;
86 
87 	if (rad_create_request(radh, RAD_ACCESS_REQUEST) == -1) {
88 		syslog(LOG_CRIT, "rad_create_request: %s", rad_strerror(radh));
89 		return (-1);
90 	}
91 	if (nas_id == NULL ||
92 	    (nas_ipaddr != NULL && strlen(nas_ipaddr) == 0)) {
93 		if (gethostname(host, sizeof host) != -1) {
94 			if (nas_id == NULL)
95 				nas_id = host;
96 			if (nas_ipaddr != NULL && strlen(nas_ipaddr) == 0)
97 				nas_ipaddr = host;
98 		}
99 	}
100 	if ((user != NULL &&
101 	    rad_put_string(radh, RAD_USER_NAME, user) == -1) ||
102 	    (pass != NULL &&
103 	    rad_put_string(radh, RAD_USER_PASSWORD, pass) == -1) ||
104 	    (nas_id != NULL &&
105 	    rad_put_string(radh, RAD_NAS_IDENTIFIER, nas_id) == -1)) {
106 		syslog(LOG_CRIT, "rad_put_string: %s", rad_strerror(radh));
107 		return (-1);
108 	}
109 	if (nas_ipaddr != NULL) {
110 		memset(&hints, 0, sizeof(hints));
111 		hints.ai_family = AF_INET;
112 		if (getaddrinfo(nas_ipaddr, NULL, &hints, &res) == 0 &&
113 		    res != NULL && res->ai_family == AF_INET) {
114 			haddr = (struct sockaddr_in *)res->ai_addr;
115 			error = rad_put_addr(radh, RAD_NAS_IP_ADDRESS,
116 			    haddr->sin_addr);
117 			freeaddrinfo(res);
118 			if (error == -1) {
119 				syslog(LOG_CRIT, "rad_put_addr: %s",
120 				    rad_strerror(radh));
121 				return (-1);
122 			}
123 		}
124 	}
125 	if (state != NULL && rad_put_attr(radh, RAD_STATE, state,
126 	    state_len) == -1) {
127 		syslog(LOG_CRIT, "rad_put_attr: %s", rad_strerror(radh));
128 		return (-1);
129 	}
130 	if (rad_put_int(radh, RAD_SERVICE_TYPE, RAD_AUTHENTICATE_ONLY) == -1) {
131 		syslog(LOG_CRIT, "rad_put_int: %s", rad_strerror(radh));
132 		return (-1);
133 	}
134 	return (0);
135 }
136 
137 static int
138 do_accept(pam_handle_t *pamh, struct rad_handle *radh)
139 {
140 	int attrtype;
141 	const void *attrval;
142 	size_t attrlen;
143 	char *s;
144 
145 	while ((attrtype = rad_get_attr(radh, &attrval, &attrlen)) > 0) {
146 		if (attrtype == RAD_USER_NAME) {
147 			s = rad_cvt_string(attrval, attrlen);
148 			if (s == NULL) {
149 				syslog(LOG_CRIT,
150 				    "rad_cvt_string: out of memory");
151 				return (-1);
152 			}
153 			pam_set_item(pamh, PAM_USER, s);
154 			free(s);
155 		}
156 	}
157 	if (attrtype == -1) {
158 		syslog(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
159 		return (-1);
160 	}
161 	return (0);
162 }
163 
164 static int
165 do_challenge(pam_handle_t *pamh, struct rad_handle *radh, const char *user)
166 {
167 	int retval;
168 	int attrtype;
169 	const void *attrval;
170 	size_t attrlen;
171 	const void *state;
172 	size_t statelen;
173 	struct pam_message msgs[MAX_CHALLENGE_MSGS];
174 	const struct pam_message *msg_ptrs[MAX_CHALLENGE_MSGS];
175 	struct pam_response *resp;
176 	int num_msgs;
177 	const void *item;
178 	const struct pam_conv *conv;
179 
180 	state = NULL;
181 	statelen = 0;
182 	num_msgs = 0;
183 	while ((attrtype = rad_get_attr(radh, &attrval, &attrlen)) > 0) {
184 		switch (attrtype) {
185 
186 		case RAD_STATE:
187 			state = attrval;
188 			statelen = attrlen;
189 			break;
190 
191 		case RAD_REPLY_MESSAGE:
192 			if (num_msgs >= MAX_CHALLENGE_MSGS) {
193 				syslog(LOG_CRIT,
194 				    "Too many RADIUS challenge messages");
195 				return (PAM_SERVICE_ERR);
196 			}
197 			msgs[num_msgs].msg = rad_cvt_string(attrval, attrlen);
198 			if (msgs[num_msgs].msg == NULL) {
199 				syslog(LOG_CRIT,
200 				    "rad_cvt_string: out of memory");
201 				return (PAM_SERVICE_ERR);
202 			}
203 			msgs[num_msgs].msg_style = PAM_TEXT_INFO;
204 			msg_ptrs[num_msgs] = &msgs[num_msgs];
205 			num_msgs++;
206 			break;
207 		}
208 	}
209 	if (attrtype == -1) {
210 		syslog(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
211 		return (PAM_SERVICE_ERR);
212 	}
213 	if (num_msgs == 0) {
214 		msgs[num_msgs].msg = strdup("(null RADIUS challenge): ");
215 		if (msgs[num_msgs].msg == NULL) {
216 			syslog(LOG_CRIT, "Out of memory");
217 			return (PAM_SERVICE_ERR);
218 		}
219 		msgs[num_msgs].msg_style = PAM_TEXT_INFO;
220 		msg_ptrs[num_msgs] = &msgs[num_msgs];
221 		num_msgs++;
222 	}
223 	msgs[num_msgs-1].msg_style = PAM_PROMPT_ECHO_ON;
224 	if ((retval = pam_get_item(pamh, PAM_CONV, &item)) != PAM_SUCCESS) {
225 		syslog(LOG_CRIT, "do_challenge: cannot get PAM_CONV");
226 		return (retval);
227 	}
228 	conv = (const struct pam_conv *)item;
229 	if ((retval = conv->conv(num_msgs, msg_ptrs, &resp,
230 	    conv->appdata_ptr)) != PAM_SUCCESS)
231 		return (retval);
232 	if (build_access_request(radh, user, resp[num_msgs-1].resp, NULL,
233 	    NULL, state, statelen) == -1)
234 		return (PAM_SERVICE_ERR);
235 	memset(resp[num_msgs-1].resp, 0, strlen(resp[num_msgs-1].resp));
236 	free(resp[num_msgs-1].resp);
237 	free(resp);
238 	while (num_msgs > 0)
239 		free(msgs[--num_msgs].msg);
240 	return (PAM_SUCCESS);
241 }
242 
243 PAM_EXTERN int
244 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
245     int argc __unused, const char *argv[] __unused)
246 {
247 	struct rad_handle *radh;
248 	const char *user, *pass;
249 	const void *tmpuser;
250 	const char *conf_file, *template_user, *nas_id, *nas_ipaddr;
251 	int retval;
252 	int e;
253 
254 	conf_file = openpam_get_option(pamh, PAM_OPT_CONF);
255 	template_user = openpam_get_option(pamh, PAM_OPT_TEMPLATE_USER);
256 	nas_id = openpam_get_option(pamh, PAM_OPT_NAS_ID);
257 	nas_ipaddr = openpam_get_option(pamh, PAM_OPT_NAS_IPADDR);
258 
259 	retval = pam_get_user(pamh, &user, NULL);
260 	if (retval != PAM_SUCCESS)
261 		return (retval);
262 
263 	PAM_LOG("Got user: %s", user);
264 
265 	retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, PASSWORD_PROMPT);
266 	if (retval != PAM_SUCCESS)
267 		return (retval);
268 
269 	PAM_LOG("Got password");
270 
271 	radh = rad_open();
272 	if (radh == NULL) {
273 		syslog(LOG_CRIT, "rad_open failed");
274 		return (PAM_SERVICE_ERR);
275 	}
276 
277 	PAM_LOG("Radius opened");
278 
279 	if (rad_config(radh, conf_file) == -1) {
280 		syslog(LOG_ALERT, "rad_config: %s", rad_strerror(radh));
281 		rad_close(radh);
282 		return (PAM_SERVICE_ERR);
283 	}
284 
285 	PAM_LOG("Radius config file read");
286 
287 	if (build_access_request(radh, user, pass, nas_id, nas_ipaddr, NULL,
288 	    0) == -1) {
289 		rad_close(radh);
290 		return (PAM_SERVICE_ERR);
291 	}
292 
293 	PAM_LOG("Radius build access done");
294 
295 	for (;;) {
296 		switch (rad_send_request(radh)) {
297 
298 		case RAD_ACCESS_ACCEPT:
299 			e = do_accept(pamh, radh);
300 			rad_close(radh);
301 			if (e == -1)
302 				return (PAM_SERVICE_ERR);
303 			if (template_user != NULL) {
304 
305 				PAM_LOG("Trying template user: %s",
306 				    template_user);
307 
308 				/*
309 				 * If the given user name doesn't exist in
310 				 * the local password database, change it
311 				 * to the value given in the "template_user"
312 				 * option.
313 				 */
314 				retval = pam_get_item(pamh, PAM_USER, &tmpuser);
315 				if (retval != PAM_SUCCESS)
316 					return (retval);
317 				if (getpwnam(tmpuser) == NULL) {
318 					pam_set_item(pamh, PAM_USER,
319 					    template_user);
320 					PAM_LOG("Using template user");
321 				}
322 
323 			}
324 			return (PAM_SUCCESS);
325 
326 		case RAD_ACCESS_REJECT:
327 			rad_close(radh);
328 			PAM_VERBOSE_ERROR("Radius rejection");
329 			return (PAM_AUTH_ERR);
330 
331 		case RAD_ACCESS_CHALLENGE:
332 			retval = do_challenge(pamh, radh, user);
333 			if (retval != PAM_SUCCESS) {
334 				rad_close(radh);
335 				return (retval);
336 			}
337 			break;
338 
339 		case -1:
340 			syslog(LOG_CRIT, "rad_send_request: %s",
341 			    rad_strerror(radh));
342 			rad_close(radh);
343 			PAM_VERBOSE_ERROR("Radius failure");
344 			return (PAM_AUTHINFO_UNAVAIL);
345 
346 		default:
347 			syslog(LOG_CRIT,
348 			    "rad_send_request: unexpected return value");
349 			rad_close(radh);
350 			PAM_VERBOSE_ERROR("Radius error");
351 			return (PAM_SERVICE_ERR);
352 		}
353 	}
354 }
355 
356 PAM_EXTERN int
357 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
358     int argc __unused, const char *argv[] __unused)
359 {
360 
361 	return (PAM_SUCCESS);
362 }
363 
364 PAM_MODULE_ENTRY("pam_radius");
365