pam_radius.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright 1998 Juniper Networks, Inc.
5 * All rights reserved.
6 * Copyright (c) 2001-2003 Networks Associates Technology, Inc.
7 * All rights reserved.
8 *
9 * Portions of this software were developed for the FreeBSD Project by
10 * ThinkSec AS and NAI Labs, the Security Research Division of Network
11 * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
12 * ("CBOSS"), as part of the DARPA CHATS research program.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 *    notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 *    notice, this list of conditions and the following disclaimer in the
21 *    documentation and/or other materials provided with the distribution.
22 * 3. The name of the author may not be used to endorse or promote
23 *    products derived from this software without specific prior written
24 *    permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 */
38
39#include <sys/cdefs.h>
40__FBSDID("$FreeBSD: stable/11/lib/libpam/modules/pam_radius/pam_radius.c 330897 2018-03-14 03:19:51Z eadler $");
41
42#include <sys/param.h>
43#include <sys/socket.h>
44#include <netdb.h>
45#include <pwd.h>
46#include <radlib.h>
47#include <stdlib.h>
48#include <string.h>
49#include <syslog.h>
50#include <unistd.h>
51
52#define PAM_SM_AUTH
53
54#include <security/pam_appl.h>
55#include <security/pam_modules.h>
56#include <security/pam_mod_misc.h>
57
58#define PAM_OPT_CONF		"conf"
59#define PAM_OPT_TEMPLATE_USER	"template_user"
60#define PAM_OPT_NAS_ID		"nas_id"
61#define PAM_OPT_NAS_IPADDR	"nas_ipaddr"
62
63#define	MAX_CHALLENGE_MSGS	10
64#define	PASSWORD_PROMPT		"RADIUS Password:"
65
66static int	 build_access_request(struct rad_handle *, const char *,
67		    const char *, const char *, const char *, const char *,
68		    const void *, size_t);
69static int	 do_accept(pam_handle_t *, struct rad_handle *);
70static int	 do_challenge(pam_handle_t *, struct rad_handle *,
71		    const char *, const char *, const char *, const char *);
72
73/*
74 * Construct an access request, but don't send it.  Returns 0 on success,
75 * -1 on failure.
76 */
77static int
78build_access_request(struct rad_handle *radh, const char *user,
79    const char *pass, const char *nas_id, const char *nas_ipaddr,
80    const char *rhost, const void *state, size_t state_len)
81{
82	int error;
83	char host[MAXHOSTNAMELEN];
84	struct sockaddr_in *haddr;
85	struct addrinfo hints;
86	struct addrinfo *res;
87
88	if (rad_create_request(radh, RAD_ACCESS_REQUEST) == -1) {
89		syslog(LOG_CRIT, "rad_create_request: %s", rad_strerror(radh));
90		return (-1);
91	}
92	if (nas_id == NULL ||
93	    (nas_ipaddr != NULL && strlen(nas_ipaddr) == 0)) {
94		if (gethostname(host, sizeof host) != -1) {
95			if (nas_id == NULL)
96				nas_id = host;
97			if (nas_ipaddr != NULL && strlen(nas_ipaddr) == 0)
98				nas_ipaddr = host;
99		}
100	}
101	if ((user != NULL &&
102	    rad_put_string(radh, RAD_USER_NAME, user) == -1) ||
103	    (pass != NULL &&
104	    rad_put_string(radh, RAD_USER_PASSWORD, pass) == -1) ||
105	    (nas_id != NULL &&
106	    rad_put_string(radh, RAD_NAS_IDENTIFIER, nas_id) == -1)) {
107		syslog(LOG_CRIT, "rad_put_string: %s", rad_strerror(radh));
108		return (-1);
109	}
110	if (nas_ipaddr != NULL) {
111		memset(&hints, 0, sizeof(hints));
112		hints.ai_family = AF_INET;
113		if (getaddrinfo(nas_ipaddr, NULL, &hints, &res) == 0 &&
114		    res != NULL && res->ai_family == AF_INET) {
115			haddr = (struct sockaddr_in *)res->ai_addr;
116			error = rad_put_addr(radh, RAD_NAS_IP_ADDRESS,
117			    haddr->sin_addr);
118			freeaddrinfo(res);
119			if (error == -1) {
120				syslog(LOG_CRIT, "rad_put_addr: %s",
121				    rad_strerror(radh));
122				return (-1);
123			}
124		}
125	}
126	if (rhost != NULL &&
127	    rad_put_string(radh, RAD_CALLING_STATION_ID, rhost) == -1) {
128		syslog(LOG_CRIT, "rad_put_string: %s", rad_strerror(radh));
129		return (-1);
130	}
131	if (state != NULL &&
132	    rad_put_attr(radh, RAD_STATE, state, state_len) == -1) {
133		syslog(LOG_CRIT, "rad_put_attr: %s", rad_strerror(radh));
134		return (-1);
135	}
136	if (rad_put_int(radh, RAD_SERVICE_TYPE, RAD_AUTHENTICATE_ONLY) == -1) {
137		syslog(LOG_CRIT, "rad_put_int: %s", rad_strerror(radh));
138		return (-1);
139	}
140	return (0);
141}
142
143static int
144do_accept(pam_handle_t *pamh, struct rad_handle *radh)
145{
146	int attrtype;
147	const void *attrval;
148	size_t attrlen;
149	char *s;
150
151	while ((attrtype = rad_get_attr(radh, &attrval, &attrlen)) > 0) {
152		if (attrtype == RAD_USER_NAME) {
153			s = rad_cvt_string(attrval, attrlen);
154			if (s == NULL) {
155				syslog(LOG_CRIT,
156				    "rad_cvt_string: out of memory");
157				return (-1);
158			}
159			pam_set_item(pamh, PAM_USER, s);
160			free(s);
161		}
162	}
163	if (attrtype == -1) {
164		syslog(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
165		return (-1);
166	}
167	return (0);
168}
169
170static int
171do_challenge(pam_handle_t *pamh, struct rad_handle *radh, const char *user,
172    const char *nas_id, const char *nas_ipaddr, const char *rhost)
173{
174	int retval;
175	int attrtype;
176	const void *attrval;
177	size_t attrlen;
178	const void *state;
179	size_t statelen;
180	struct pam_message msgs[MAX_CHALLENGE_MSGS];
181	const struct pam_message *msg_ptrs[MAX_CHALLENGE_MSGS];
182	struct pam_response *resp;
183	int num_msgs;
184	const void *item;
185	const struct pam_conv *conv;
186
187	state = NULL;
188	statelen = 0;
189	num_msgs = 0;
190	while ((attrtype = rad_get_attr(radh, &attrval, &attrlen)) > 0) {
191		switch (attrtype) {
192
193		case RAD_STATE:
194			state = attrval;
195			statelen = attrlen;
196			break;
197
198		case RAD_REPLY_MESSAGE:
199			if (num_msgs >= MAX_CHALLENGE_MSGS) {
200				syslog(LOG_CRIT,
201				    "Too many RADIUS challenge messages");
202				return (PAM_SERVICE_ERR);
203			}
204			msgs[num_msgs].msg = rad_cvt_string(attrval, attrlen);
205			if (msgs[num_msgs].msg == NULL) {
206				syslog(LOG_CRIT,
207				    "rad_cvt_string: out of memory");
208				return (PAM_SERVICE_ERR);
209			}
210			msgs[num_msgs].msg_style = PAM_TEXT_INFO;
211			msg_ptrs[num_msgs] = &msgs[num_msgs];
212			num_msgs++;
213			break;
214		}
215	}
216	if (attrtype == -1) {
217		syslog(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
218		return (PAM_SERVICE_ERR);
219	}
220	if (num_msgs == 0) {
221		msgs[num_msgs].msg = strdup("(null RADIUS challenge): ");
222		if (msgs[num_msgs].msg == NULL) {
223			syslog(LOG_CRIT, "Out of memory");
224			return (PAM_SERVICE_ERR);
225		}
226		msgs[num_msgs].msg_style = PAM_TEXT_INFO;
227		msg_ptrs[num_msgs] = &msgs[num_msgs];
228		num_msgs++;
229	}
230	msgs[num_msgs-1].msg_style = PAM_PROMPT_ECHO_ON;
231	if ((retval = pam_get_item(pamh, PAM_CONV, &item)) != PAM_SUCCESS) {
232		syslog(LOG_CRIT, "do_challenge: cannot get PAM_CONV");
233		return (retval);
234	}
235	conv = (const struct pam_conv *)item;
236	if ((retval = conv->conv(num_msgs, msg_ptrs, &resp,
237	    conv->appdata_ptr)) != PAM_SUCCESS)
238		return (retval);
239	if (build_access_request(radh, user, resp[num_msgs-1].resp, nas_id,
240	    nas_ipaddr, rhost, state, statelen) == -1)
241		return (PAM_SERVICE_ERR);
242	memset(resp[num_msgs-1].resp, 0, strlen(resp[num_msgs-1].resp));
243	free(resp[num_msgs-1].resp);
244	free(resp);
245	while (num_msgs > 0)
246		free(msgs[--num_msgs].msg);
247	return (PAM_SUCCESS);
248}
249
250PAM_EXTERN int
251pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
252    int argc __unused, const char *argv[] __unused)
253{
254	struct rad_handle *radh;
255	const char *user, *pass;
256	const void *rhost, *tmpuser;
257	const char *conf_file, *template_user, *nas_id, *nas_ipaddr;
258	int retval;
259	int e;
260
261	conf_file = openpam_get_option(pamh, PAM_OPT_CONF);
262	template_user = openpam_get_option(pamh, PAM_OPT_TEMPLATE_USER);
263	nas_id = openpam_get_option(pamh, PAM_OPT_NAS_ID);
264	nas_ipaddr = openpam_get_option(pamh, PAM_OPT_NAS_IPADDR);
265	pam_get_item(pamh, PAM_RHOST, &rhost);
266
267	retval = pam_get_user(pamh, &user, NULL);
268	if (retval != PAM_SUCCESS)
269		return (retval);
270
271	PAM_LOG("Got user: %s", user);
272
273	retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, PASSWORD_PROMPT);
274	if (retval != PAM_SUCCESS)
275		return (retval);
276
277	PAM_LOG("Got password");
278
279	radh = rad_open();
280	if (radh == NULL) {
281		syslog(LOG_CRIT, "rad_open failed");
282		return (PAM_SERVICE_ERR);
283	}
284
285	PAM_LOG("Radius opened");
286
287	if (rad_config(radh, conf_file) == -1) {
288		syslog(LOG_ALERT, "rad_config: %s", rad_strerror(radh));
289		rad_close(radh);
290		return (PAM_SERVICE_ERR);
291	}
292
293	PAM_LOG("Radius config file read");
294
295	if (build_access_request(radh, user, pass, nas_id, nas_ipaddr, rhost,
296	    NULL, 0) == -1) {
297		rad_close(radh);
298		return (PAM_SERVICE_ERR);
299	}
300
301	PAM_LOG("Radius build access done");
302
303	for (;;) {
304		switch (rad_send_request(radh)) {
305
306		case RAD_ACCESS_ACCEPT:
307			e = do_accept(pamh, radh);
308			rad_close(radh);
309			if (e == -1)
310				return (PAM_SERVICE_ERR);
311			if (template_user != NULL) {
312
313				PAM_LOG("Trying template user: %s",
314				    template_user);
315
316				/*
317				 * If the given user name doesn't exist in
318				 * the local password database, change it
319				 * to the value given in the "template_user"
320				 * option.
321				 */
322				retval = pam_get_item(pamh, PAM_USER, &tmpuser);
323				if (retval != PAM_SUCCESS)
324					return (retval);
325				if (getpwnam(tmpuser) == NULL) {
326					pam_set_item(pamh, PAM_USER,
327					    template_user);
328					PAM_LOG("Using template user");
329				}
330
331			}
332			return (PAM_SUCCESS);
333
334		case RAD_ACCESS_REJECT:
335			rad_close(radh);
336			PAM_VERBOSE_ERROR("Radius rejection");
337			return (PAM_AUTH_ERR);
338
339		case RAD_ACCESS_CHALLENGE:
340			retval = do_challenge(pamh, radh, user, nas_id,
341			    nas_ipaddr, rhost);
342			if (retval != PAM_SUCCESS) {
343				rad_close(radh);
344				return (retval);
345			}
346			break;
347
348		case -1:
349			syslog(LOG_CRIT, "rad_send_request: %s",
350			    rad_strerror(radh));
351			rad_close(radh);
352			PAM_VERBOSE_ERROR("Radius failure");
353			return (PAM_AUTHINFO_UNAVAIL);
354
355		default:
356			syslog(LOG_CRIT,
357			    "rad_send_request: unexpected return value");
358			rad_close(radh);
359			PAM_VERBOSE_ERROR("Radius error");
360			return (PAM_SERVICE_ERR);
361		}
362	}
363}
364
365PAM_EXTERN int
366pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
367    int argc __unused, const char *argv[] __unused)
368{
369
370	return (PAM_SUCCESS);
371}
372
373PAM_MODULE_ENTRY("pam_radius");
374