pam_radius.c revision 122571 
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: head/lib/libpam/modules/pam_radius/pam_radius.c 122571 2003-11-12 17:47:23Z sobomax $");
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
65static int	 build_access_request(struct rad_handle *, const char *,
66		    const char *, const char *, const char *, const void *,
67		    size_t);
68static int	 do_accept(pam_handle_t *, struct rad_handle *);
69static 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 */
76static int
77build_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 = PF_INET;
112		if (getaddrinfo(nas_ipaddr, NULL, &hints, &res) == 0 &&
113		    res != NULL) {
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
137static int
138do_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
164static int
165do_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
243PAM_EXTERN int
244pam_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, *tmpuser, *pass;
249	const char *conf_file, *template_user, *nas_id, *nas_ipaddr;
250	int retval;
251	int e;
252
253	conf_file = openpam_get_option(pamh, PAM_OPT_CONF);
254	template_user = openpam_get_option(pamh, PAM_OPT_TEMPLATE_USER);
255	nas_id = openpam_get_option(pamh, PAM_OPT_NAS_ID);
256	nas_ipaddr = openpam_get_option(pamh, PAM_OPT_NAS_IPADDR);
257
258	retval = pam_get_user(pamh, &user, NULL);
259	if (retval != PAM_SUCCESS)
260		return (retval);
261
262	PAM_LOG("Got user: %s", user);
263
264	retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, PASSWORD_PROMPT);
265	if (retval != PAM_SUCCESS)
266		return (retval);
267
268	PAM_LOG("Got password");
269
270	radh = rad_open();
271	if (radh == NULL) {
272		syslog(LOG_CRIT, "rad_open failed");
273		return (PAM_SERVICE_ERR);
274	}
275
276	PAM_LOG("Radius opened");
277
278	if (rad_config(radh, conf_file) == -1) {
279		syslog(LOG_ALERT, "rad_config: %s", rad_strerror(radh));
280		rad_close(radh);
281		return (PAM_SERVICE_ERR);
282	}
283
284	PAM_LOG("Radius config file read");
285
286	if (build_access_request(radh, user, pass, nas_id, nas_ipaddr, NULL,
287	    0) == -1) {
288		rad_close(radh);
289		return (PAM_SERVICE_ERR);
290	}
291
292	PAM_LOG("Radius build access done");
293
294	for (;;) {
295		switch (rad_send_request(radh)) {
296
297		case RAD_ACCESS_ACCEPT:
298			e = do_accept(pamh, radh);
299			rad_close(radh);
300			if (e == -1)
301				return (PAM_SERVICE_ERR);
302			if (template_user != NULL) {
303
304				PAM_LOG("Trying template user: %s",
305				    template_user);
306
307				/*
308				 * If the given user name doesn't exist in
309				 * the local password database, change it
310				 * to the value given in the "template_user"
311				 * option.
312				 */
313				retval = pam_get_item(pamh, PAM_USER,
314				    (const void **)&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
356PAM_EXTERN int
357pam_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
364PAM_MODULE_ENTRY("pam_radius");
365