lib/libpam/modules/pam_radius/pam_radius.c

   1 /*      $NetBSD: pam_radius.c,v 1.6 2006/11/03 18:04:20 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 1.6 2006/11/03 18:04:20 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");