lib/pam_module/pam_radius/pam_radius.c

   1 /*-
   2  * Copyright 1998 Juniper Networks, Inc.
   3  * All rights reserved.
   4  * Copyright (c) 2001-2003 Networks Associates Technology, Inc.
   5  * All rights reserved.
   6  *
   7  * Portions of this software were developed for the FreeBSD Project by
   8  * ThinkSec AS and NAI Labs, the Security Research Division of Network
   9  * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
  10  * ("CBOSS"), as part of the DARPA CHATS research program.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. The name of the author may not be used to endorse or promote
  21  *    products derived from this software without specific prior written
  22  *    permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * $FreeBSD: src/lib/libpam/modules/pam_radius/pam_radius.c,v 1.23 2005/06/13 21:18:52 des Exp $
  37  * $DragonFly: src/lib/pam_module/pam_radius/pam_radius.c,v 1.1 2005/07/12 23:13:26 joerg Exp $
  38  */
  39
  40 #include <sys/param.h>
  41 #include <sys/socket.h>
  42 #include <netdb.h>
  43 #include <pwd.h>
  44 #include <radlib.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include <syslog.h>
  48 #include <unistd.h>
  49
  50 #define PAM_SM_AUTH
  51
  52 #include <security/pam_appl.h>
  53 #include <security/pam_modules.h>
  54 #include <security/pam_mod_misc.h>
  55
  56 #define PAM_OPT_CONF            "conf"
  57 #define PAM_OPT_TEMPLATE_USER   "template_user"
  58 #define PAM_OPT_NAS_ID          "nas_id"
  59 #define PAM_OPT_NAS_IPADDR      "nas_ipaddr"
  60
  61 #define MAX_CHALLENGE_MSGS      10
  62 #define PASSWORD_PROMPT         "RADIUS Password:"
  63
  64 static int       build_access_request(struct rad_handle *, const char *,
  65                     const char *, const char *, const char *, const void *,
  66                     size_t);
  67 static int       do_accept(pam_handle_t *, struct rad_handle *);
  68 static int       do_challenge(pam_handle_t *, struct rad_handle *,
  69                     const char *);
  70
  71 /*
  72  * Construct an access request, but don't send it.  Returns 0 on success,
  73  * -1 on failure.
  74  */
  75 static int
  76 build_access_request(struct rad_handle *radh, const char *user,
  77     const char *pass, const char *nas_id, const char *nas_ipaddr,
  78     const void *state, size_t state_len)
  79 {
  80         int error;
  81         char host[MAXHOSTNAMELEN];
  82         struct sockaddr_in *haddr;
  83         struct addrinfo hints;
  84         struct addrinfo *res;
  85
  86         if (rad_create_request(radh, RAD_ACCESS_REQUEST) == -1) {
  87                 syslog(LOG_CRIT, "rad_create_request: %s", rad_strerror(radh));
  88                 return (-1);
  89         }
  90         if (nas_id == NULL ||
  91             (nas_ipaddr != NULL && strlen(nas_ipaddr) == 0)) {
  92                 if (gethostname(host, sizeof host) != -1) {
  93                         if (nas_id == NULL)
  94                                 nas_id = host;
  95                         if (nas_ipaddr != NULL && strlen(nas_ipaddr) == 0)
  96                                 nas_ipaddr = host;
  97                 }
  98         }
  99         if ((user != NULL &&
 100             rad_put_string(radh, RAD_USER_NAME, user) == -1) ||
 101             (pass != NULL &&
 102             rad_put_string(radh, RAD_USER_PASSWORD, pass) == -1) ||
 103             (nas_id != NULL &&
 104             rad_put_string(radh, RAD_NAS_IDENTIFIER, nas_id) == -1)) {
 105                 syslog(LOG_CRIT, "rad_put_string: %s", rad_strerror(radh));
 106                 return (-1);
 107         }
 108         if (nas_ipaddr != NULL) {
 109                 memset(&hints, 0, sizeof(hints));
 110                 hints.ai_family = AF_INET;
 111                 if (getaddrinfo(nas_ipaddr, NULL, &hints, &res) == 0 &&
 112                     res != NULL && res->ai_family == AF_INET) {
 113                         haddr = (struct sockaddr_in *)res->ai_addr;
 114                         error = rad_put_addr(radh, RAD_NAS_IP_ADDRESS,
 115                             haddr->sin_addr);
 116                         freeaddrinfo(res);
 117                         if (error == -1) {
 118                                 syslog(LOG_CRIT, "rad_put_addr: %s",
 119                                     rad_strerror(radh));
 120                                 return (-1);
 121                         }
 122                 }
 123         }
 124         if (state != NULL && rad_put_attr(radh, RAD_STATE, state,
 125             state_len) == -1) {
 126                 syslog(LOG_CRIT, "rad_put_attr: %s", rad_strerror(radh));
 127                 return (-1);
 128         }
 129         if (rad_put_int(radh, RAD_SERVICE_TYPE, RAD_AUTHENTICATE_ONLY) == -1) {
 130                 syslog(LOG_CRIT, "rad_put_int: %s", rad_strerror(radh));
 131                 return (-1);
 132         }
 133         return (0);
 134 }
 135
 136 static int
 137 do_accept(pam_handle_t *pamh, struct rad_handle *radh)
 138 {
 139         int attrtype;
 140         const void *attrval;
 141         size_t attrlen;
 142         char *s;
 143
 144         while ((attrtype = rad_get_attr(radh, &attrval, &attrlen)) > 0) {
 145                 if (attrtype == RAD_USER_NAME) {
 146                         s = rad_cvt_string(attrval, attrlen);
 147                         if (s == NULL) {
 148                                 syslog(LOG_CRIT,
 149                                     "rad_cvt_string: out of memory");
 150                                 return (-1);
 151                         }
 152                         pam_set_item(pamh, PAM_USER, s);
 153                         free(s);
 154                 }
 155         }
 156         if (attrtype == -1) {
 157                 syslog(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
 158                 return (-1);
 159         }
 160         return (0);
 161 }
 162
 163 static int
 164 do_challenge(pam_handle_t *pamh, struct rad_handle *radh, const char *user)
 165 {
 166         int retval;
 167         int attrtype;
 168         const void *attrval;
 169         size_t attrlen;
 170         const void *state;
 171         size_t statelen;
 172         struct pam_message msgs[MAX_CHALLENGE_MSGS];
 173         const struct pam_message *msg_ptrs[MAX_CHALLENGE_MSGS];
 174         struct pam_response *resp;
 175         int num_msgs;
 176         const void *item;
 177         const struct pam_conv *conv;
 178
 179         state = NULL;
 180         statelen = 0;
 181         num_msgs = 0;
 182         while ((attrtype = rad_get_attr(radh, &attrval, &attrlen)) > 0) {
 183                 switch (attrtype) {
 184
 185                 case RAD_STATE:
 186                         state = attrval;
 187                         statelen = attrlen;
 188                         break;
 189
 190                 case RAD_REPLY_MESSAGE:
 191                         if (num_msgs >= MAX_CHALLENGE_MSGS) {
 192                                 syslog(LOG_CRIT,
 193                                     "Too many RADIUS challenge messages");
 194                                 return (PAM_SERVICE_ERR);
 195                         }
 196                         msgs[num_msgs].msg = rad_cvt_string(attrval, attrlen);
 197                         if (msgs[num_msgs].msg == NULL) {
 198                                 syslog(LOG_CRIT,
 199                                     "rad_cvt_string: out of memory");
 200                                 return (PAM_SERVICE_ERR);
 201                         }
 202                         msgs[num_msgs].msg_style = PAM_TEXT_INFO;
 203                         msg_ptrs[num_msgs] = &msgs[num_msgs];
 204                         num_msgs++;
 205                         break;
 206                 }
 207         }
 208         if (attrtype == -1) {
 209                 syslog(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
 210                 return (PAM_SERVICE_ERR);
 211         }
 212         if (num_msgs == 0) {
 213                 msgs[num_msgs].msg = strdup("(null RADIUS challenge): ");
 214                 if (msgs[num_msgs].msg == NULL) {
 215                         syslog(LOG_CRIT, "Out of memory");
 216                         return (PAM_SERVICE_ERR);
 217                 }
 218                 msgs[num_msgs].msg_style = PAM_TEXT_INFO;
 219                 msg_ptrs[num_msgs] = &msgs[num_msgs];
 220                 num_msgs++;
 221         }
 222         msgs[num_msgs-1].msg_style = PAM_PROMPT_ECHO_ON;
 223         if ((retval = pam_get_item(pamh, PAM_CONV, &item)) != PAM_SUCCESS) {
 224                 syslog(LOG_CRIT, "do_challenge: cannot get PAM_CONV");
 225                 return (retval);
 226         }
 227         conv = (const struct pam_conv *)item;
 228         if ((retval = conv->conv(num_msgs, msg_ptrs, &resp,
 229             conv->appdata_ptr)) != PAM_SUCCESS)
 230                 return (retval);
 231         if (build_access_request(radh, user, resp[num_msgs-1].resp, NULL,
 232             NULL, state, statelen) == -1)
 233                 return (PAM_SERVICE_ERR);
 234         memset(resp[num_msgs-1].resp, 0, strlen(resp[num_msgs-1].resp));
 235         free(resp[num_msgs-1].resp);
 236         free(resp);
 237         while (num_msgs > 0)
 238                 free(msgs[--num_msgs].msg);
 239         return (PAM_SUCCESS);
 240 }
 241
 242 PAM_EXTERN int
 243 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
 244     int argc __unused, const char *argv[] __unused)
 245 {
 246         struct rad_handle *radh;
 247         const char *user, *pass;
 248         const void *tmpuser;
 249         const char *conf_file, *template_user, *nas_id, *nas_ipaddr;
 250         int retval;
 251         int e;
 252
 253         conf_file = openpam_get_option(pamh, PAM_OPT_CONF);
 254         template_user = openpam_get_option(pamh, PAM_OPT_TEMPLATE_USER);
 255         nas_id = openpam_get_option(pamh, PAM_OPT_NAS_ID);
 256         nas_ipaddr = openpam_get_option(pamh, PAM_OPT_NAS_IPADDR);
 257
 258         retval = pam_get_user(pamh, &user, NULL);
 259         if (retval != PAM_SUCCESS)
 260                 return (retval);
 261
 262         PAM_LOG("Got user: %s", user);
 263
 264         retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, PASSWORD_PROMPT);
 265         if (retval != PAM_SUCCESS)
 266                 return (retval);
 267
 268         PAM_LOG("Got password");
 269
 270         radh = rad_open();
 271         if (radh == NULL) {
 272                 syslog(LOG_CRIT, "rad_open failed");
 273                 return (PAM_SERVICE_ERR);
 274         }
 275
 276         PAM_LOG("Radius opened");
 277
 278         if (rad_config(radh, conf_file) == -1) {
 279                 syslog(LOG_ALERT, "rad_config: %s", rad_strerror(radh));
 280                 rad_close(radh);
 281                 return (PAM_SERVICE_ERR);
 282         }
 283
 284         PAM_LOG("Radius config file read");
 285
 286         if (build_access_request(radh, user, pass, nas_id, nas_ipaddr, NULL,
 287             0) == -1) {
 288                 rad_close(radh);
 289                 return (PAM_SERVICE_ERR);
 290         }
 291
 292         PAM_LOG("Radius build access done");
 293
 294         for (;;) {
 295                 switch (rad_send_request(radh)) {
 296
 297                 case RAD_ACCESS_ACCEPT:
 298                         e = do_accept(pamh, radh);
 299                         rad_close(radh);
 300                         if (e == -1)
 301                                 return (PAM_SERVICE_ERR);
 302                         if (template_user != NULL) {
 303
 304                                 PAM_LOG("Trying template user: %s",
 305                                     template_user);
 306
 307                                 /*
 308                                  * If the given user name doesn't exist in
 309                                  * the local password database, change it
 310                                  * to the value given in the "template_user"
 311                                  * option.
 312                                  */
 313                                 retval = pam_get_item(pamh, PAM_USER, &tmpuser);
 314                                 if (retval != PAM_SUCCESS)
 315                                         return (retval);
 316                                 if (getpwnam(tmpuser) == NULL) {
 317                                         pam_set_item(pamh, PAM_USER,
 318                                             template_user);
 319                                         PAM_LOG("Using template user");
 320                                 }
 321
 322                         }
 323                         return (PAM_SUCCESS);
 324
 325                 case RAD_ACCESS_REJECT:
 326                         rad_close(radh);
 327                         PAM_VERBOSE_ERROR("Radius rejection");
 328                         return (PAM_AUTH_ERR);
 329
 330                 case RAD_ACCESS_CHALLENGE:
 331                         retval = do_challenge(pamh, radh, user);
 332                         if (retval != PAM_SUCCESS) {
 333                                 rad_close(radh);
 334                                 return (retval);
 335                         }
 336                         break;
 337
 338                 case -1:
 339                         syslog(LOG_CRIT, "rad_send_request: %s",
 340                             rad_strerror(radh));
 341                         rad_close(radh);
 342                         PAM_VERBOSE_ERROR("Radius failure");
 343                         return (PAM_AUTHINFO_UNAVAIL);
 344
 345                 default:
 346                         syslog(LOG_CRIT,
 347                             "rad_send_request: unexpected return value");
 348                         rad_close(radh);
 349                         PAM_VERBOSE_ERROR("Radius error");
 350                         return (PAM_SERVICE_ERR);
 351                 }
 352         }
 353 }
 354
 355 PAM_EXTERN int
 356 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
 357     int argc __unused, const char *argv[] __unused)
 358 {
 359
 360         return (PAM_SUCCESS);
 361 }
 362
 363 PAM_MODULE_ENTRY("pam_radius");