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/cdefs.h>
42__FBSDID("$FreeBSD$");
43
44#include <sys/param.h>
45#include <sys/socket.h>
46#include <netdb.h>
47#include <pwd.h>
48#include <radlib.h>
49#include <stdlib.h>
50#include <string.h>
51#include <syslog.h>
52#include <unistd.h>
53
54#define PAM_SM_AUTH
55
56#include <security/pam_appl.h>
57#include <security/pam_modules.h>
58#include <security/pam_mod_misc.h>
59
60#define PAM_OPT_CONF		"conf"
61#define PAM_OPT_TEMPLATE_USER	"template_user"
62#define PAM_OPT_NAS_ID		"nas_id"
63#define PAM_OPT_NAS_IPADDR	"nas_ipaddr"
64#define PAM_OPT_NO_REPLYMSG	"no_reply_message"
65
66#define	MAX_CHALLENGE_MSGS	10
67#define	PASSWORD_PROMPT		"RADIUS Password:"
68
69static int	 build_access_request(struct rad_handle *, const char *,
70		    const char *, const char *, const char *, const char *,
71		    const void *, size_t);
72static int	 do_accept(pam_handle_t *, struct rad_handle *);
73static int	 do_challenge(pam_handle_t *, struct rad_handle *,
74		    const char *, const char *, const char *, const char *);
75
76/*
77 * Construct an access request, but don't send it.  Returns 0 on success,
78 * -1 on failure.
79 */
80static int
81build_access_request(struct rad_handle *radh, const char *user,
82    const char *pass, const char *nas_id, const char *nas_ipaddr,
83    const char *rhost, const void *state, size_t state_len)
84{
85	int error;
86	char host[MAXHOSTNAMELEN];
87	struct sockaddr_in *haddr;
88	struct addrinfo hints;
89	struct addrinfo *res;
90
91	if (rad_create_request(radh, RAD_ACCESS_REQUEST) == -1) {
92		syslog(LOG_CRIT, "rad_create_request: %s", rad_strerror(radh));
93		return (-1);
94	}
95	if (nas_id == NULL ||
96	    (nas_ipaddr != NULL && strlen(nas_ipaddr) == 0)) {
97		if (gethostname(host, sizeof host) != -1) {
98			if (nas_id == NULL)
99				nas_id = host;
100			if (nas_ipaddr != NULL && strlen(nas_ipaddr) == 0)
101				nas_ipaddr = host;
102		}
103	}
104	if ((user != NULL &&
105	    rad_put_string(radh, RAD_USER_NAME, user) == -1) ||
106	    (pass != NULL &&
107	    rad_put_string(radh, RAD_USER_PASSWORD, pass) == -1) ||
108	    (nas_id != NULL &&
109	    rad_put_string(radh, RAD_NAS_IDENTIFIER, nas_id) == -1)) {
110		syslog(LOG_CRIT, "rad_put_string: %s", rad_strerror(radh));
111		return (-1);
112	}
113	if (nas_ipaddr != NULL) {
114		memset(&hints, 0, sizeof(hints));
115		hints.ai_family = AF_INET;
116		if (getaddrinfo(nas_ipaddr, NULL, &hints, &res) == 0 &&
117		    res != NULL && res->ai_family == AF_INET) {
118			haddr = (struct sockaddr_in *)res->ai_addr;
119			error = rad_put_addr(radh, RAD_NAS_IP_ADDRESS,
120			    haddr->sin_addr);
121			freeaddrinfo(res);
122			if (error == -1) {
123				syslog(LOG_CRIT, "rad_put_addr: %s",
124				    rad_strerror(radh));
125				return (-1);
126			}
127		}
128	}
129	if (rhost != NULL &&
130	    rad_put_string(radh, RAD_CALLING_STATION_ID, rhost) == -1) {
131		syslog(LOG_CRIT, "rad_put_string: %s", rad_strerror(radh));
132		return (-1);
133	}
134	if (state != NULL &&
135	    rad_put_attr(radh, RAD_STATE, state, state_len) == -1) {
136		syslog(LOG_CRIT, "rad_put_attr: %s", rad_strerror(radh));
137		return (-1);
138	}
139	if (rad_put_int(radh, RAD_SERVICE_TYPE, RAD_AUTHENTICATE_ONLY) == -1) {
140		syslog(LOG_CRIT, "rad_put_int: %s", rad_strerror(radh));
141		return (-1);
142	}
143	return (0);
144}
145
146static int
147do_accept(pam_handle_t *pamh, struct rad_handle *radh)
148{
149	int attrtype;
150	const void *attrval;
151	size_t attrlen;
152	char *s;
153
154	while ((attrtype = rad_get_attr(radh, &attrval, &attrlen)) > 0) {
155		switch (attrtype) {
156		case RAD_USER_NAME:
157			if ((s = rad_cvt_string(attrval, attrlen)) == NULL)
158				goto enomem;
159			pam_set_item(pamh, PAM_USER, s);
160			free(s);
161			break;
162		case RAD_REPLY_MESSAGE:
163			if ((s = rad_cvt_string(attrval, attrlen)) == NULL)
164				goto enomem;
165			if (!openpam_get_option(pamh, PAM_OPT_NO_REPLYMSG))
166				pam_info(pamh, "%s", s);
167			free(s);
168			break;
169		default:
170			PAM_LOG("%s(): ignoring RADIUS attribute %d",
171			    __func__, attrtype);
172		}
173	}
174	if (attrtype == -1) {
175		syslog(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
176		return (-1);
177	}
178	return (0);
179enomem:
180	syslog(LOG_CRIT, "%s(): out of memory", __func__);
181	return (-1);
182}
183
184static int
185do_reject(pam_handle_t *pamh, struct rad_handle *radh)
186{
187	int attrtype;
188	const void *attrval;
189	size_t attrlen;
190	char *s;
191
192	while ((attrtype = rad_get_attr(radh, &attrval, &attrlen)) > 0) {
193		switch (attrtype) {
194		case RAD_REPLY_MESSAGE:
195			if ((s = rad_cvt_string(attrval, attrlen)) == NULL)
196				goto enomem;
197			if (!openpam_get_option(pamh, PAM_OPT_NO_REPLYMSG))
198				pam_error(pamh, "%s", s);
199			free(s);
200			break;
201		default:
202			PAM_LOG("%s(): ignoring RADIUS attribute %d",
203			    __func__, attrtype);
204		}
205	}
206	if (attrtype < 0) {
207		syslog(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
208		return (-1);
209	}
210	return (0);
211enomem:
212	syslog(LOG_CRIT, "%s(): out of memory", __func__);
213	return (-1);
214}
215
216static int
217do_challenge(pam_handle_t *pamh, struct rad_handle *radh, const char *user,
218    const char *nas_id, const char *nas_ipaddr, const char *rhost)
219{
220	int retval;
221	int attrtype;
222	const void *attrval;
223	size_t attrlen;
224	const void *state;
225	size_t statelen;
226	struct pam_message msgs[MAX_CHALLENGE_MSGS];
227	const struct pam_message *msg_ptrs[MAX_CHALLENGE_MSGS];
228	struct pam_response *resp;
229	int num_msgs;
230	const void *item;
231	const struct pam_conv *conv;
232
233	state = NULL;
234	statelen = 0;
235	num_msgs = 0;
236	while ((attrtype = rad_get_attr(radh, &attrval, &attrlen)) > 0) {
237		switch (attrtype) {
238
239		case RAD_STATE:
240			state = attrval;
241			statelen = attrlen;
242			break;
243
244		case RAD_REPLY_MESSAGE:
245			if (num_msgs >= MAX_CHALLENGE_MSGS) {
246				syslog(LOG_CRIT,
247				    "Too many RADIUS challenge messages");
248				return (PAM_SERVICE_ERR);
249			}
250			msgs[num_msgs].msg = rad_cvt_string(attrval, attrlen);
251			if (msgs[num_msgs].msg == NULL) {
252				syslog(LOG_CRIT,
253				    "rad_cvt_string: out of memory");
254				return (PAM_SERVICE_ERR);
255			}
256			msgs[num_msgs].msg_style = PAM_TEXT_INFO;
257			msg_ptrs[num_msgs] = &msgs[num_msgs];
258			num_msgs++;
259			break;
260		}
261	}
262	if (attrtype == -1) {
263		syslog(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
264		return (PAM_SERVICE_ERR);
265	}
266	if (num_msgs == 0) {
267		msgs[num_msgs].msg = strdup("(null RADIUS challenge): ");
268		if (msgs[num_msgs].msg == NULL) {
269			syslog(LOG_CRIT, "Out of memory");
270			return (PAM_SERVICE_ERR);
271		}
272		msgs[num_msgs].msg_style = PAM_TEXT_INFO;
273		msg_ptrs[num_msgs] = &msgs[num_msgs];
274		num_msgs++;
275	}
276	msgs[num_msgs-1].msg_style = PAM_PROMPT_ECHO_ON;
277	if ((retval = pam_get_item(pamh, PAM_CONV, &item)) != PAM_SUCCESS) {
278		syslog(LOG_CRIT, "do_challenge: cannot get PAM_CONV");
279		return (retval);
280	}
281	conv = (const struct pam_conv *)item;
282	if ((retval = conv->conv(num_msgs, msg_ptrs, &resp,
283	    conv->appdata_ptr)) != PAM_SUCCESS)
284		return (retval);
285	if (build_access_request(radh, user, resp[num_msgs-1].resp, nas_id,
286	    nas_ipaddr, rhost, state, statelen) == -1)
287		return (PAM_SERVICE_ERR);
288	memset(resp[num_msgs-1].resp, 0, strlen(resp[num_msgs-1].resp));
289	free(resp[num_msgs-1].resp);
290	free(resp);
291	while (num_msgs > 0)
292		free(msgs[--num_msgs].msg);
293	return (PAM_SUCCESS);
294}
295
296PAM_EXTERN int
297pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
298    int argc __unused, const char *argv[] __unused)
299{
300	struct rad_handle *radh;
301	const char *user, *pass;
302	const void *rhost, *tmpuser;
303	const char *conf_file, *template_user, *nas_id, *nas_ipaddr;
304	int retval;
305	int e;
306
307	conf_file = openpam_get_option(pamh, PAM_OPT_CONF);
308	template_user = openpam_get_option(pamh, PAM_OPT_TEMPLATE_USER);
309	nas_id = openpam_get_option(pamh, PAM_OPT_NAS_ID);
310	nas_ipaddr = openpam_get_option(pamh, PAM_OPT_NAS_IPADDR);
311	pam_get_item(pamh, PAM_RHOST, &rhost);
312
313	retval = pam_get_user(pamh, &user, NULL);
314	if (retval != PAM_SUCCESS)
315		return (retval);
316
317	PAM_LOG("Got user: %s", user);
318
319	retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, PASSWORD_PROMPT);
320	if (retval != PAM_SUCCESS)
321		return (retval);
322
323	PAM_LOG("Got password");
324
325	radh = rad_open();
326	if (radh == NULL) {
327		syslog(LOG_CRIT, "rad_open failed");
328		return (PAM_SERVICE_ERR);
329	}
330
331	PAM_LOG("Radius opened");
332
333	if (rad_config(radh, conf_file) == -1) {
334		syslog(LOG_ALERT, "rad_config: %s", rad_strerror(radh));
335		rad_close(radh);
336		return (PAM_SERVICE_ERR);
337	}
338
339	PAM_LOG("Radius config file read");
340
341	if (build_access_request(radh, user, pass, nas_id, nas_ipaddr, rhost,
342	    NULL, 0) == -1) {
343		rad_close(radh);
344		return (PAM_SERVICE_ERR);
345	}
346
347	PAM_LOG("Radius build access done");
348
349	for (;;) {
350		switch (rad_send_request(radh)) {
351
352		case RAD_ACCESS_ACCEPT:
353			e = do_accept(pamh, radh);
354			rad_close(radh);
355			if (e == -1)
356				return (PAM_SERVICE_ERR);
357			if (template_user != NULL) {
358
359				PAM_LOG("Trying template user: %s",
360				    template_user);
361
362				/*
363				 * If the given user name doesn't exist in
364				 * the local password database, change it
365				 * to the value given in the "template_user"
366				 * option.
367				 */
368				retval = pam_get_item(pamh, PAM_USER, &tmpuser);
369				if (retval != PAM_SUCCESS)
370					return (retval);
371				if (getpwnam(tmpuser) == NULL) {
372					pam_set_item(pamh, PAM_USER,
373					    template_user);
374					PAM_LOG("Using template user");
375				}
376
377			}
378			return (PAM_SUCCESS);
379
380		case RAD_ACCESS_REJECT:
381			retval = do_reject(pamh, radh);
382			rad_close(radh);
383			PAM_VERBOSE_ERROR("Radius rejection");
384			return (PAM_AUTH_ERR);
385
386		case RAD_ACCESS_CHALLENGE:
387			retval = do_challenge(pamh, radh, user, nas_id,
388			    nas_ipaddr, rhost);
389			if (retval != PAM_SUCCESS) {
390				rad_close(radh);
391				return (retval);
392			}
393			break;
394
395		case -1:
396			syslog(LOG_CRIT, "rad_send_request: %s",
397			    rad_strerror(radh));
398			rad_close(radh);
399			PAM_VERBOSE_ERROR("Radius failure");
400			return (PAM_AUTHINFO_UNAVAIL);
401
402		default:
403			syslog(LOG_CRIT,
404			    "rad_send_request: unexpected return value");
405			rad_close(radh);
406			PAM_VERBOSE_ERROR("Radius error");
407			return (PAM_SERVICE_ERR);
408		}
409	}
410}
411
412PAM_EXTERN int
413pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
414    int argc __unused, const char *argv[] __unused)
415{
416
417	return (PAM_SUCCESS);
418}
419
420PAM_MODULE_ENTRY("pam_radius");
421