pam_radius.c revision 277873 
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: stable/10/lib/libpam/modules/pam_radius/pam_radius.c 277873 2015-01-29 09:03:57Z des $");
39
40#include <sys/param.h>
41#include <sys/socket.h>
42#include <netdb.h>
43#include <pwd.h>
44#include <radlib.h>
45#include <stdlib.h>
46#include <string.h>
47#include <syslog.h>
48#include <unistd.h>
49
50#define PAM_SM_AUTH
51
52#include <security/pam_appl.h>
53#include <security/pam_modules.h>
54#include <security/pam_mod_misc.h>
55
56#define PAM_OPT_CONF		"conf"
57#define PAM_OPT_TEMPLATE_USER	"template_user"
58#define PAM_OPT_NAS_ID		"nas_id"
59#define PAM_OPT_NAS_IPADDR	"nas_ipaddr"
60
61#define	MAX_CHALLENGE_MSGS	10
62#define	PASSWORD_PROMPT		"RADIUS Password:"
63
64static int	 build_access_request(struct rad_handle *, const char *,
65		    const char *, const char *, const char *, const char *,
66		    const void *, size_t);
67static int	 do_accept(pam_handle_t *, struct rad_handle *);
68static int	 do_challenge(pam_handle_t *, struct rad_handle *,
69		    const char *, const char *, const char *, const char *);
70
71/*
72 * Construct an access request, but don't send it.  Returns 0 on success,
73 * -1 on failure.
74 */
75static int
76build_access_request(struct rad_handle *radh, const char *user,
77    const char *pass, const char *nas_id, const char *nas_ipaddr,
78    const char *rhost, const void *state, size_t state_len)
79{
80	int error;
81	char host[MAXHOSTNAMELEN];
82	struct sockaddr_in *haddr;
83	struct addrinfo hints;
84	struct addrinfo *res;
85
86	if (rad_create_request(radh, RAD_ACCESS_REQUEST) == -1) {
87		syslog(LOG_CRIT, "rad_create_request: %s", rad_strerror(radh));
88		return (-1);
89	}
90	if (nas_id == NULL ||
91	    (nas_ipaddr != NULL && strlen(nas_ipaddr) == 0)) {
92		if (gethostname(host, sizeof host) != -1) {
93			if (nas_id == NULL)
94				nas_id = host;
95			if (nas_ipaddr != NULL && strlen(nas_ipaddr) == 0)
96				nas_ipaddr = host;
97		}
98	}
99	if ((user != NULL &&
100	    rad_put_string(radh, RAD_USER_NAME, user) == -1) ||
101	    (pass != NULL &&
102	    rad_put_string(radh, RAD_USER_PASSWORD, pass) == -1) ||
103	    (nas_id != NULL &&
104	    rad_put_string(radh, RAD_NAS_IDENTIFIER, nas_id) == -1)) {
105		syslog(LOG_CRIT, "rad_put_string: %s", rad_strerror(radh));
106		return (-1);
107	}
108	if (nas_ipaddr != NULL) {
109		memset(&hints, 0, sizeof(hints));
110		hints.ai_family = AF_INET;
111		if (getaddrinfo(nas_ipaddr, NULL, &hints, &res) == 0 &&
112		    res != NULL && res->ai_family == AF_INET) {
113			haddr = (struct sockaddr_in *)res->ai_addr;
114			error = rad_put_addr(radh, RAD_NAS_IP_ADDRESS,
115			    haddr->sin_addr);
116			freeaddrinfo(res);
117			if (error == -1) {
118				syslog(LOG_CRIT, "rad_put_addr: %s",
119				    rad_strerror(radh));
120				return (-1);
121			}
122		}
123	}
124	if (rhost != NULL &&
125	    rad_put_string(radh, RAD_CALLING_STATION_ID, rhost) == -1) {
126		syslog(LOG_CRIT, "rad_put_string: %s", rad_strerror(radh));
127		return (-1);
128	}
129	if (state != NULL &&
130	    rad_put_attr(radh, RAD_STATE, state, state_len) == -1) {
131		syslog(LOG_CRIT, "rad_put_attr: %s", rad_strerror(radh));
132		return (-1);
133	}
134	if (rad_put_int(radh, RAD_SERVICE_TYPE, RAD_AUTHENTICATE_ONLY) == -1) {
135		syslog(LOG_CRIT, "rad_put_int: %s", rad_strerror(radh));
136		return (-1);
137	}
138	return (0);
139}
140
141static int
142do_accept(pam_handle_t *pamh, struct rad_handle *radh)
143{
144	int attrtype;
145	const void *attrval;
146	size_t attrlen;
147	char *s;
148
149	while ((attrtype = rad_get_attr(radh, &attrval, &attrlen)) > 0) {
150		if (attrtype == RAD_USER_NAME) {
151			s = rad_cvt_string(attrval, attrlen);
152			if (s == NULL) {
153				syslog(LOG_CRIT,
154				    "rad_cvt_string: out of memory");
155				return (-1);
156			}
157			pam_set_item(pamh, PAM_USER, s);
158			free(s);
159		}
160	}
161	if (attrtype == -1) {
162		syslog(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
163		return (-1);
164	}
165	return (0);
166}
167
168static int
169do_challenge(pam_handle_t *pamh, struct rad_handle *radh, const char *user,
170    const char *nas_id, const char *nas_ipaddr, const char *rhost)
171{
172	int retval;
173	int attrtype;
174	const void *attrval;
175	size_t attrlen;
176	const void *state;
177	size_t statelen;
178	struct pam_message msgs[MAX_CHALLENGE_MSGS];
179	const struct pam_message *msg_ptrs[MAX_CHALLENGE_MSGS];
180	struct pam_response *resp;
181	int num_msgs;
182	const void *item;
183	const struct pam_conv *conv;
184
185	state = NULL;
186	statelen = 0;
187	num_msgs = 0;
188	while ((attrtype = rad_get_attr(radh, &attrval, &attrlen)) > 0) {
189		switch (attrtype) {
190
191		case RAD_STATE:
192			state = attrval;
193			statelen = attrlen;
194			break;
195
196		case RAD_REPLY_MESSAGE:
197			if (num_msgs >= MAX_CHALLENGE_MSGS) {
198				syslog(LOG_CRIT,
199				    "Too many RADIUS challenge messages");
200				return (PAM_SERVICE_ERR);
201			}
202			msgs[num_msgs].msg = rad_cvt_string(attrval, attrlen);
203			if (msgs[num_msgs].msg == NULL) {
204				syslog(LOG_CRIT,
205				    "rad_cvt_string: out of memory");
206				return (PAM_SERVICE_ERR);
207			}
208			msgs[num_msgs].msg_style = PAM_TEXT_INFO;
209			msg_ptrs[num_msgs] = &msgs[num_msgs];
210			num_msgs++;
211			break;
212		}
213	}
214	if (attrtype == -1) {
215		syslog(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
216		return (PAM_SERVICE_ERR);
217	}
218	if (num_msgs == 0) {
219		msgs[num_msgs].msg = strdup("(null RADIUS challenge): ");
220		if (msgs[num_msgs].msg == NULL) {
221			syslog(LOG_CRIT, "Out of memory");
222			return (PAM_SERVICE_ERR);
223		}
224		msgs[num_msgs].msg_style = PAM_TEXT_INFO;
225		msg_ptrs[num_msgs] = &msgs[num_msgs];
226		num_msgs++;
227	}
228	msgs[num_msgs-1].msg_style = PAM_PROMPT_ECHO_ON;
229	if ((retval = pam_get_item(pamh, PAM_CONV, &item)) != PAM_SUCCESS) {
230		syslog(LOG_CRIT, "do_challenge: cannot get PAM_CONV");
231		return (retval);
232	}
233	conv = (const struct pam_conv *)item;
234	if ((retval = conv->conv(num_msgs, msg_ptrs, &resp,
235	    conv->appdata_ptr)) != PAM_SUCCESS)
236		return (retval);
237	if (build_access_request(radh, user, resp[num_msgs-1].resp, nas_id,
238	    nas_ipaddr, rhost, state, statelen) == -1)
239		return (PAM_SERVICE_ERR);
240	memset(resp[num_msgs-1].resp, 0, strlen(resp[num_msgs-1].resp));
241	free(resp[num_msgs-1].resp);
242	free(resp);
243	while (num_msgs > 0)
244		free(msgs[--num_msgs].msg);
245	return (PAM_SUCCESS);
246}
247
248PAM_EXTERN int
249pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
250    int argc __unused, const char *argv[] __unused)
251{
252	struct rad_handle *radh;
253	const char *user, *pass;
254	const void *rhost, *tmpuser;
255	const char *conf_file, *template_user, *nas_id, *nas_ipaddr;
256	int retval;
257	int e;
258
259	conf_file = openpam_get_option(pamh, PAM_OPT_CONF);
260	template_user = openpam_get_option(pamh, PAM_OPT_TEMPLATE_USER);
261	nas_id = openpam_get_option(pamh, PAM_OPT_NAS_ID);
262	nas_ipaddr = openpam_get_option(pamh, PAM_OPT_NAS_IPADDR);
263	pam_get_item(pamh, PAM_RHOST, &rhost);
264
265	retval = pam_get_user(pamh, &user, NULL);
266	if (retval != PAM_SUCCESS)
267		return (retval);
268
269	PAM_LOG("Got user: %s", user);
270
271	retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, PASSWORD_PROMPT);
272	if (retval != PAM_SUCCESS)
273		return (retval);
274
275	PAM_LOG("Got password");
276
277	radh = rad_open();
278	if (radh == NULL) {
279		syslog(LOG_CRIT, "rad_open failed");
280		return (PAM_SERVICE_ERR);
281	}
282
283	PAM_LOG("Radius opened");
284
285	if (rad_config(radh, conf_file) == -1) {
286		syslog(LOG_ALERT, "rad_config: %s", rad_strerror(radh));
287		rad_close(radh);
288		return (PAM_SERVICE_ERR);
289	}
290
291	PAM_LOG("Radius config file read");
292
293	if (build_access_request(radh, user, pass, nas_id, nas_ipaddr, rhost,
294	    NULL, 0) == -1) {
295		rad_close(radh);
296		return (PAM_SERVICE_ERR);
297	}
298
299	PAM_LOG("Radius build access done");
300
301	for (;;) {
302		switch (rad_send_request(radh)) {
303
304		case RAD_ACCESS_ACCEPT:
305			e = do_accept(pamh, radh);
306			rad_close(radh);
307			if (e == -1)
308				return (PAM_SERVICE_ERR);
309			if (template_user != NULL) {
310
311				PAM_LOG("Trying template user: %s",
312				    template_user);
313
314				/*
315				 * If the given user name doesn't exist in
316				 * the local password database, change it
317				 * to the value given in the "template_user"
318				 * option.
319				 */
320				retval = pam_get_item(pamh, PAM_USER, &tmpuser);
321				if (retval != PAM_SUCCESS)
322					return (retval);
323				if (getpwnam(tmpuser) == NULL) {
324					pam_set_item(pamh, PAM_USER,
325					    template_user);
326					PAM_LOG("Using template user");
327				}
328
329			}
330			return (PAM_SUCCESS);
331
332		case RAD_ACCESS_REJECT:
333			rad_close(radh);
334			PAM_VERBOSE_ERROR("Radius rejection");
335			return (PAM_AUTH_ERR);
336
337		case RAD_ACCESS_CHALLENGE:
338			retval = do_challenge(pamh, radh, user, nas_id,
339			    nas_ipaddr, rhost);
340			if (retval != PAM_SUCCESS) {
341				rad_close(radh);
342				return (retval);
343			}
344			break;
345
346		case -1:
347			syslog(LOG_CRIT, "rad_send_request: %s",
348			    rad_strerror(radh));
349			rad_close(radh);
350			PAM_VERBOSE_ERROR("Radius failure");
351			return (PAM_AUTHINFO_UNAVAIL);
352
353		default:
354			syslog(LOG_CRIT,
355			    "rad_send_request: unexpected return value");
356			rad_close(radh);
357			PAM_VERBOSE_ERROR("Radius error");
358			return (PAM_SERVICE_ERR);
359		}
360	}
361}
362
363PAM_EXTERN int
364pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
365    int argc __unused, const char *argv[] __unused)
366{
367
368	return (PAM_SUCCESS);
369}
370
371PAM_MODULE_ENTRY("pam_radius");
372