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 * Copyright (c) 2015-2018 The University of Oslo
9 * All rights reserved.
10 *
11 * Portions of this software were developed for the FreeBSD Project by
12 * ThinkSec AS and NAI Labs, the Security Research Division of Network
13 * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
14 * ("CBOSS"), as part of the DARPA CHATS research program.
15 *
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
18 * are met:
19 * 1. Redistributions of source code must retain the above copyright
20 *    notice, this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright
22 *    notice, this list of conditions and the following disclaimer in the
23 *    documentation and/or other materials provided with the distribution.
24 * 3. The name of the author may not be used to endorse or promote
25 *    products derived from this software without specific prior written
26 *    permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * SUCH DAMAGE.
39 */
40
41#include <sys/param.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#define PAM_OPT_NO_REPLYMSG	"no_reply_message"
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		switch (attrtype) {
153		case RAD_USER_NAME:
154			if ((s = rad_cvt_string(attrval, attrlen)) == NULL)
155				goto enomem;
156			pam_set_item(pamh, PAM_USER, s);
157			free(s);
158			break;
159		case RAD_REPLY_MESSAGE:
160			if ((s = rad_cvt_string(attrval, attrlen)) == NULL)
161				goto enomem;
162			if (!openpam_get_option(pamh, PAM_OPT_NO_REPLYMSG))
163				pam_info(pamh, "%s", s);
164			free(s);
165			break;
166		default:
167			PAM_LOG("%s(): ignoring RADIUS attribute %d",
168			    __func__, attrtype);
169		}
170	}
171	if (attrtype == -1) {
172		syslog(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
173		return (-1);
174	}
175	return (0);
176enomem:
177	syslog(LOG_CRIT, "%s(): out of memory", __func__);
178	return (-1);
179}
180
181static int
182do_reject(pam_handle_t *pamh, struct rad_handle *radh)
183{
184	int attrtype;
185	const void *attrval;
186	size_t attrlen;
187	char *s;
188
189	while ((attrtype = rad_get_attr(radh, &attrval, &attrlen)) > 0) {
190		switch (attrtype) {
191		case RAD_REPLY_MESSAGE:
192			if ((s = rad_cvt_string(attrval, attrlen)) == NULL)
193				goto enomem;
194			if (!openpam_get_option(pamh, PAM_OPT_NO_REPLYMSG))
195				pam_error(pamh, "%s", s);
196			free(s);
197			break;
198		default:
199			PAM_LOG("%s(): ignoring RADIUS attribute %d",
200			    __func__, attrtype);
201		}
202	}
203	if (attrtype < 0) {
204		syslog(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
205		return (-1);
206	}
207	return (0);
208enomem:
209	syslog(LOG_CRIT, "%s(): out of memory", __func__);
210	return (-1);
211}
212
213static int
214do_challenge(pam_handle_t *pamh, struct rad_handle *radh, const char *user,
215    const char *nas_id, const char *nas_ipaddr, const char *rhost)
216{
217	int retval;
218	int attrtype;
219	const void *attrval;
220	size_t attrlen;
221	const void *state;
222	size_t statelen;
223	struct pam_message msgs[MAX_CHALLENGE_MSGS];
224	const struct pam_message *msg_ptrs[MAX_CHALLENGE_MSGS];
225	struct pam_response *resp;
226	int num_msgs;
227	const void *item;
228	const struct pam_conv *conv;
229
230	state = NULL;
231	statelen = 0;
232	num_msgs = 0;
233	while ((attrtype = rad_get_attr(radh, &attrval, &attrlen)) > 0) {
234		switch (attrtype) {
235
236		case RAD_STATE:
237			state = attrval;
238			statelen = attrlen;
239			break;
240
241		case RAD_REPLY_MESSAGE:
242			if (num_msgs >= MAX_CHALLENGE_MSGS) {
243				syslog(LOG_CRIT,
244				    "Too many RADIUS challenge messages");
245				return (PAM_SERVICE_ERR);
246			}
247			msgs[num_msgs].msg = rad_cvt_string(attrval, attrlen);
248			if (msgs[num_msgs].msg == NULL) {
249				syslog(LOG_CRIT,
250				    "rad_cvt_string: out of memory");
251				return (PAM_SERVICE_ERR);
252			}
253			msgs[num_msgs].msg_style = PAM_TEXT_INFO;
254			msg_ptrs[num_msgs] = &msgs[num_msgs];
255			num_msgs++;
256			break;
257		}
258	}
259	if (attrtype == -1) {
260		syslog(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
261		return (PAM_SERVICE_ERR);
262	}
263	if (num_msgs == 0) {
264		msgs[num_msgs].msg = strdup("(null RADIUS challenge): ");
265		if (msgs[num_msgs].msg == NULL) {
266			syslog(LOG_CRIT, "Out of memory");
267			return (PAM_SERVICE_ERR);
268		}
269		msgs[num_msgs].msg_style = PAM_TEXT_INFO;
270		msg_ptrs[num_msgs] = &msgs[num_msgs];
271		num_msgs++;
272	}
273	msgs[num_msgs-1].msg_style = PAM_PROMPT_ECHO_ON;
274	if ((retval = pam_get_item(pamh, PAM_CONV, &item)) != PAM_SUCCESS) {
275		syslog(LOG_CRIT, "do_challenge: cannot get PAM_CONV");
276		return (retval);
277	}
278	conv = (const struct pam_conv *)item;
279	if ((retval = conv->conv(num_msgs, msg_ptrs, &resp,
280	    conv->appdata_ptr)) != PAM_SUCCESS)
281		return (retval);
282	if (build_access_request(radh, user, resp[num_msgs-1].resp, nas_id,
283	    nas_ipaddr, rhost, state, statelen) == -1)
284		return (PAM_SERVICE_ERR);
285	memset(resp[num_msgs-1].resp, 0, strlen(resp[num_msgs-1].resp));
286	free(resp[num_msgs-1].resp);
287	free(resp);
288	while (num_msgs > 0)
289		free(msgs[--num_msgs].msg);
290	return (PAM_SUCCESS);
291}
292
293PAM_EXTERN int
294pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
295    int argc __unused, const char *argv[] __unused)
296{
297	struct rad_handle *radh;
298	const char *user, *pass;
299	const void *rhost, *tmpuser;
300	const char *conf_file, *template_user, *nas_id, *nas_ipaddr;
301	int retval;
302	int e;
303
304	conf_file = openpam_get_option(pamh, PAM_OPT_CONF);
305	template_user = openpam_get_option(pamh, PAM_OPT_TEMPLATE_USER);
306	nas_id = openpam_get_option(pamh, PAM_OPT_NAS_ID);
307	nas_ipaddr = openpam_get_option(pamh, PAM_OPT_NAS_IPADDR);
308	pam_get_item(pamh, PAM_RHOST, &rhost);
309
310	retval = pam_get_user(pamh, &user, NULL);
311	if (retval != PAM_SUCCESS)
312		return (retval);
313
314	PAM_LOG("Got user: %s", user);
315
316	retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, PASSWORD_PROMPT);
317	if (retval != PAM_SUCCESS)
318		return (retval);
319
320	PAM_LOG("Got password");
321
322	radh = rad_open();
323	if (radh == NULL) {
324		syslog(LOG_CRIT, "rad_open failed");
325		return (PAM_SERVICE_ERR);
326	}
327
328	PAM_LOG("Radius opened");
329
330	if (rad_config(radh, conf_file) == -1) {
331		syslog(LOG_ALERT, "rad_config: %s", rad_strerror(radh));
332		rad_close(radh);
333		return (PAM_SERVICE_ERR);
334	}
335
336	PAM_LOG("Radius config file read");
337
338	if (build_access_request(radh, user, pass, nas_id, nas_ipaddr, rhost,
339	    NULL, 0) == -1) {
340		rad_close(radh);
341		return (PAM_SERVICE_ERR);
342	}
343
344	PAM_LOG("Radius build access done");
345
346	for (;;) {
347		switch (rad_send_request(radh)) {
348
349		case RAD_ACCESS_ACCEPT:
350			e = do_accept(pamh, radh);
351			rad_close(radh);
352			if (e == -1)
353				return (PAM_SERVICE_ERR);
354			if (template_user != NULL) {
355
356				PAM_LOG("Trying template user: %s",
357				    template_user);
358
359				/*
360				 * If the given user name doesn't exist in
361				 * the local password database, change it
362				 * to the value given in the "template_user"
363				 * option.
364				 */
365				retval = pam_get_item(pamh, PAM_USER, &tmpuser);
366				if (retval != PAM_SUCCESS)
367					return (retval);
368				if (getpwnam(tmpuser) == NULL) {
369					pam_set_item(pamh, PAM_USER,
370					    template_user);
371					PAM_LOG("Using template user");
372				}
373
374			}
375			return (PAM_SUCCESS);
376
377		case RAD_ACCESS_REJECT:
378			retval = do_reject(pamh, radh);
379			rad_close(radh);
380			PAM_VERBOSE_ERROR("Radius rejection");
381			return (PAM_AUTH_ERR);
382
383		case RAD_ACCESS_CHALLENGE:
384			retval = do_challenge(pamh, radh, user, nas_id,
385			    nas_ipaddr, rhost);
386			if (retval != PAM_SUCCESS) {
387				rad_close(radh);
388				return (retval);
389			}
390			break;
391
392		case -1:
393			syslog(LOG_CRIT, "rad_send_request: %s",
394			    rad_strerror(radh));
395			rad_close(radh);
396			PAM_VERBOSE_ERROR("Radius failure");
397			return (PAM_AUTHINFO_UNAVAIL);
398
399		default:
400			syslog(LOG_CRIT,
401			    "rad_send_request: unexpected return value");
402			rad_close(radh);
403			PAM_VERBOSE_ERROR("Radius error");
404			return (PAM_SERVICE_ERR);
405		}
406	}
407}
408
409PAM_EXTERN int
410pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
411    int argc __unused, const char *argv[] __unused)
412{
413
414	return (PAM_SUCCESS);
415}
416
417PAM_MODULE_ENTRY("pam_radius");
418