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pam_radius.c revision 1.7
      1 /*	$NetBSD: pam_radius.c,v 1.7 2006/11/03 18:55:40 christos Exp $	*/
      2 
      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 #ifdef __FreeBSD__
     41 __FBSDID("$FreeBSD: src/lib/libpam/modules/pam_radius/pam_radius.c,v 1.22 2004/06/25 12:32:45 kan Exp $");
     42 #else
     43 __RCSID("$NetBSD: pam_radius.c,v 1.7 2006/11/03 18:55:40 christos Exp $");
     44 #endif
     45 
     46 #include <sys/param.h>
     47 #include <sys/types.h>
     48 #include <sys/socket.h>
     49 #include <netdb.h>
     50 #include <pwd.h>
     51 #include <radlib.h>
     52 #include <stdlib.h>
     53 #include <string.h>
     54 #include <syslog.h>
     55 #include <unistd.h>
     56 #include <stdarg.h>
     57 
     58 #define PAM_SM_AUTH
     59 
     60 #include <security/pam_appl.h>
     61 #include <security/pam_modules.h>
     62 #include <security/pam_mod_misc.h>
     63 
     64 #define PAM_OPT_CONF		"conf"
     65 #define PAM_OPT_TEMPLATE_USER	"template_user"
     66 #define PAM_OPT_NAS_ID		"nas_id"
     67 #define PAM_OPT_NAS_IPADDR	"nas_ipaddr"
     68 
     69 #define	MAX_CHALLENGE_MSGS	10
     70 #define	PASSWORD_PROMPT		"RADIUS Password:"
     71 
     72 static int	 build_access_request(struct rad_handle *, const char *,
     73 		    const char *, const char *, const char *, const void *,
     74 		    size_t);
     75 static int	 do_accept(pam_handle_t *, struct rad_handle *);
     76 static int	 do_challenge(pam_handle_t *, struct rad_handle *,
     77 		    const char *);
     78 
     79 static void
     80 logit(int level, const char *fmt, ...)
     81 {
     82 	va_list ap;
     83 	struct syslog_data data = SYSLOG_DATA_INIT;
     84 
     85 	openlog_r("pam_radius", LOG_PID, LOG_AUTHPRIV, &data);
     86 	va_start(ap, fmt);
     87 	vsyslog_r(level, &data, fmt, ap);
     88 	va_end(ap);
     89 	closelog_r(&data);
     90 }
     91 
     92 /*
     93  * Construct an access request, but don't send it.  Returns 0 on success,
     94  * -1 on failure.
     95  */
     96 static int
     97 build_access_request(struct rad_handle *radh, const char *user,
     98     const char *pass, const char *nas_id, const char *nas_ipaddr,
     99     const void *state, size_t state_len)
    100 {
    101 	int error;
    102 	char host[MAXHOSTNAMELEN];
    103 	struct sockaddr_in *haddr;
    104 	struct addrinfo hints;
    105 	struct addrinfo *res;
    106 
    107 	if (rad_create_request(radh, RAD_ACCESS_REQUEST) == -1) {
    108 		logit(LOG_CRIT, "rad_create_request: %s", rad_strerror(radh));
    109 		return (-1);
    110 	}
    111 	if (nas_id == NULL ||
    112 	    (nas_ipaddr != NULL && strlen(nas_ipaddr) == 0)) {
    113 		if (gethostname(host, sizeof host) != -1) {
    114 			if (nas_id == NULL)
    115 				nas_id = host;
    116 			if (nas_ipaddr != NULL && strlen(nas_ipaddr) == 0)
    117 				nas_ipaddr = host;
    118 		}
    119 	}
    120 	if ((user != NULL &&
    121 	    rad_put_string(radh, RAD_USER_NAME, user) == -1) ||
    122 	    (pass != NULL &&
    123 	    rad_put_string(radh, RAD_USER_PASSWORD, pass) == -1) ||
    124 	    (nas_id != NULL &&
    125 	    rad_put_string(radh, RAD_NAS_IDENTIFIER, nas_id) == -1)) {
    126 		logit(LOG_CRIT, "rad_put_string: %s", rad_strerror(radh));
    127 		return (-1);
    128 	}
    129 	if (nas_ipaddr != NULL) {
    130 		memset(&hints, 0, sizeof(hints));
    131 		hints.ai_family = PF_INET;
    132 		if (getaddrinfo(nas_ipaddr, NULL, &hints, &res) == 0 &&
    133 		    res != NULL) {
    134 			haddr = (struct sockaddr_in *)res->ai_addr;
    135 			error = rad_put_addr(radh, RAD_NAS_IP_ADDRESS,
    136 			    haddr->sin_addr);
    137 			freeaddrinfo(res);
    138 			if (error == -1) {
    139 				logit(LOG_CRIT, "rad_put_addr: %s",
    140 				    rad_strerror(radh));
    141 				return (-1);
    142 			}
    143 		}
    144 	}
    145 	if (state != NULL && rad_put_attr(radh, RAD_STATE, state,
    146 	    state_len) == -1) {
    147 		logit(LOG_CRIT, "rad_put_attr: %s", rad_strerror(radh));
    148 		return (-1);
    149 	}
    150 	if (rad_put_int(radh, RAD_SERVICE_TYPE, RAD_AUTHENTICATE_ONLY) == -1) {
    151 		logit(LOG_CRIT, "rad_put_int: %s", rad_strerror(radh));
    152 		return (-1);
    153 	}
    154 	return (0);
    155 }
    156 
    157 static int
    158 do_accept(pam_handle_t *pamh, struct rad_handle *radh)
    159 {
    160 	int attrtype;
    161 	const void *attrval;
    162 	size_t attrlen;
    163 	char *s;
    164 
    165 	while ((attrtype = rad_get_attr(radh, &attrval, &attrlen)) > 0) {
    166 		if (attrtype == RAD_USER_NAME) {
    167 			s = rad_cvt_string(attrval, attrlen);
    168 			if (s == NULL) {
    169 				logit(LOG_CRIT,
    170 				    "rad_cvt_string: out of memory");
    171 				return (-1);
    172 			}
    173 			pam_set_item(pamh, PAM_USER, s);
    174 			free(s);
    175 		}
    176 	}
    177 	if (attrtype == -1) {
    178 		logit(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
    179 		return (-1);
    180 	}
    181 	return (0);
    182 }
    183 
    184 static int
    185 do_challenge(pam_handle_t *pamh, struct rad_handle *radh, const char *user)
    186 {
    187 	int retval;
    188 	int attrtype;
    189 	const void *attrval;
    190 	size_t attrlen;
    191 	const void *state;
    192 	size_t statelen;
    193 	struct pam_message msgs[MAX_CHALLENGE_MSGS];
    194 	const struct pam_message *msg_ptrs[MAX_CHALLENGE_MSGS];
    195 	struct pam_response *resp;
    196 	int num_msgs;
    197 	const void *item;
    198 	const struct pam_conv *conv;
    199 
    200 	state = NULL;
    201 	statelen = 0;
    202 	num_msgs = 0;
    203 	while ((attrtype = rad_get_attr(radh, &attrval, &attrlen)) > 0) {
    204 		switch (attrtype) {
    205 
    206 		case RAD_STATE:
    207 			state = attrval;
    208 			statelen = attrlen;
    209 			break;
    210 
    211 		case RAD_REPLY_MESSAGE:
    212 			if (num_msgs >= MAX_CHALLENGE_MSGS) {
    213 				logit(LOG_CRIT,
    214 				    "Too many RADIUS challenge messages");
    215 				return (PAM_SERVICE_ERR);
    216 			}
    217 			msgs[num_msgs].msg = rad_cvt_string(attrval, attrlen);
    218 			if (msgs[num_msgs].msg == NULL) {
    219 				logit(LOG_CRIT,
    220 				    "rad_cvt_string: out of memory");
    221 				return (PAM_SERVICE_ERR);
    222 			}
    223 			msgs[num_msgs].msg_style = PAM_TEXT_INFO;
    224 			msg_ptrs[num_msgs] = &msgs[num_msgs];
    225 			num_msgs++;
    226 			break;
    227 		}
    228 	}
    229 	if (attrtype == -1) {
    230 		logit(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
    231 		return (PAM_SERVICE_ERR);
    232 	}
    233 	if (num_msgs == 0) {
    234 		msgs[num_msgs].msg = strdup("(null RADIUS challenge): ");
    235 		if (msgs[num_msgs].msg == NULL) {
    236 			logit(LOG_CRIT, "Out of memory");
    237 			return (PAM_SERVICE_ERR);
    238 		}
    239 		msgs[num_msgs].msg_style = PAM_TEXT_INFO;
    240 		msg_ptrs[num_msgs] = &msgs[num_msgs];
    241 		num_msgs++;
    242 	}
    243 	msgs[num_msgs-1].msg_style = PAM_PROMPT_ECHO_ON;
    244 	if ((retval = pam_get_item(pamh, PAM_CONV, &item)) != PAM_SUCCESS) {
    245 		logit(LOG_CRIT, "do_challenge: cannot get PAM_CONV");
    246 		return (retval);
    247 	}
    248 	conv = (const struct pam_conv *)item;
    249 	if ((retval = conv->conv(num_msgs, msg_ptrs, &resp,
    250 	    conv->appdata_ptr)) != PAM_SUCCESS)
    251 		return (retval);
    252 	if (build_access_request(radh, user, resp[num_msgs-1].resp, NULL,
    253 	    NULL, state, statelen) == -1)
    254 		return (PAM_SERVICE_ERR);
    255 	memset(resp[num_msgs-1].resp, 0, strlen(resp[num_msgs-1].resp));
    256 	free(resp[num_msgs-1].resp);
    257 	free(resp);
    258 	while (num_msgs > 0)
    259 		free(msgs[--num_msgs].msg);
    260 	return (PAM_SUCCESS);
    261 }
    262 
    263 PAM_EXTERN int
    264 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
    265     int argc __unused, const char *argv[] __unused)
    266 {
    267 	struct rad_handle *radh;
    268 	const char *user, *pass;
    269 	const void *tmpuser;
    270 	struct passwd *pwd, pwres;
    271 	char pwbuf[1024];
    272 	const char *conf_file, *template_user, *nas_id, *nas_ipaddr;
    273 	int retval;
    274 	int e;
    275 
    276 	conf_file = openpam_get_option(pamh, PAM_OPT_CONF);
    277 	template_user = openpam_get_option(pamh, PAM_OPT_TEMPLATE_USER);
    278 	nas_id = openpam_get_option(pamh, PAM_OPT_NAS_ID);
    279 	nas_ipaddr = openpam_get_option(pamh, PAM_OPT_NAS_IPADDR);
    280 
    281 	retval = pam_get_user(pamh, &user, NULL);
    282 	if (retval != PAM_SUCCESS)
    283 		return (retval);
    284 
    285 	PAM_LOG("Got user: %s", user);
    286 
    287 	retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, PASSWORD_PROMPT);
    288 	if (retval != PAM_SUCCESS)
    289 		return (retval);
    290 
    291 	PAM_LOG("Got password");
    292 
    293 	radh = rad_open();
    294 	if (radh == NULL) {
    295 		logit(LOG_CRIT, "rad_open failed");
    296 		return (PAM_SERVICE_ERR);
    297 	}
    298 
    299 	PAM_LOG("Radius opened");
    300 
    301 	if (rad_config(radh, conf_file) == -1) {
    302 		logit(LOG_ALERT, "rad_config: %s", rad_strerror(radh));
    303 		rad_close(radh);
    304 		return (PAM_SERVICE_ERR);
    305 	}
    306 
    307 	PAM_LOG("Radius config file read");
    308 
    309 	if (build_access_request(radh, user, pass, nas_id, nas_ipaddr, NULL,
    310 	    0) == -1) {
    311 		rad_close(radh);
    312 		return (PAM_SERVICE_ERR);
    313 	}
    314 
    315 	PAM_LOG("Radius build access done");
    316 
    317 	for (;;) {
    318 		switch (rad_send_request(radh)) {
    319 
    320 		case RAD_ACCESS_ACCEPT:
    321 			e = do_accept(pamh, radh);
    322 			rad_close(radh);
    323 			if (e == -1)
    324 				return (PAM_SERVICE_ERR);
    325 			if (template_user != NULL) {
    326 
    327 				PAM_LOG("Trying template user: %s",
    328 				    template_user);
    329 
    330 				/*
    331 				 * If the given user name doesn't exist in
    332 				 * the local password database, change it
    333 				 * to the value given in the "template_user"
    334 				 * option.
    335 				 */
    336 				retval = pam_get_item(pamh, PAM_USER, &tmpuser);
    337 				if (retval != PAM_SUCCESS)
    338 					return (retval);
    339 				if (getpwnam_r(tmpuser, &pwres, pwbuf,
    340 					       sizeof(pwbuf), &pwd) != 0 ||
    341 				    pwd == NULL) {
    342 					pam_set_item(pamh, PAM_USER,
    343 					    template_user);
    344 					PAM_LOG("Using template user");
    345 				}
    346 
    347 			}
    348 			return (PAM_SUCCESS);
    349 
    350 		case RAD_ACCESS_REJECT:
    351 			rad_close(radh);
    352 			PAM_VERBOSE_ERROR("Radius rejection");
    353 			return (PAM_AUTH_ERR);
    354 
    355 		case RAD_ACCESS_CHALLENGE:
    356 			retval = do_challenge(pamh, radh, user);
    357 			if (retval != PAM_SUCCESS) {
    358 				rad_close(radh);
    359 				return (retval);
    360 			}
    361 			break;
    362 
    363 		case -1:
    364 			logit(LOG_CRIT, "rad_send_request: %s",
    365 			    rad_strerror(radh));
    366 			rad_close(radh);
    367 			PAM_VERBOSE_ERROR("Radius failure");
    368 			return (PAM_AUTHINFO_UNAVAIL);
    369 
    370 		default:
    371 			logit(LOG_CRIT,
    372 			    "rad_send_request: unexpected return value");
    373 			rad_close(radh);
    374 			PAM_VERBOSE_ERROR("Radius error");
    375 			return (PAM_SERVICE_ERR);
    376 		}
    377 	}
    378 }
    379 
    380 PAM_EXTERN int
    381 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
    382     int argc __unused, const char *argv[] __unused)
    383 {
    384 
    385 	return (PAM_SUCCESS);
    386 }
    387 
    388 PAM_MODULE_ENTRY("pam_radius");
    389