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 1.24 2007/01/20 08:52:04 pjd 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 *, const char *, 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     const char *nas_id, const char *nas_ipaddr)
 166 {
 167         int retval;
 168         int attrtype;
 169         const void *attrval;
 170         size_t attrlen;
 171         const void *state;
 172         size_t statelen;
 173         struct pam_message msgs[MAX_CHALLENGE_MSGS];
 174         const struct pam_message *msg_ptrs[MAX_CHALLENGE_MSGS];
 175         struct pam_response *resp;
 176         int num_msgs;
 177         const void *item;
 178         const struct pam_conv *conv;
 179
 180         state = NULL;
 181         statelen = 0;
 182         num_msgs = 0;
 183         while ((attrtype = rad_get_attr(radh, &attrval, &attrlen)) > 0) {
 184                 switch (attrtype) {
 185
 186                 case RAD_STATE:
 187                         state = attrval;
 188                         statelen = attrlen;
 189                         break;
 190
 191                 case RAD_REPLY_MESSAGE:
 192                         if (num_msgs >= MAX_CHALLENGE_MSGS) {
 193                                 syslog(LOG_CRIT,
 194                                     "Too many RADIUS challenge messages");
 195                                 return (PAM_SERVICE_ERR);
 196                         }
 197                         msgs[num_msgs].msg = rad_cvt_string(attrval, attrlen);
 198                         if (msgs[num_msgs].msg == NULL) {
 199                                 syslog(LOG_CRIT,
 200                                     "rad_cvt_string: out of memory");
 201                                 return (PAM_SERVICE_ERR);
 202                         }
 203                         msgs[num_msgs].msg_style = PAM_TEXT_INFO;
 204                         msg_ptrs[num_msgs] = &msgs[num_msgs];
 205                         num_msgs++;
 206                         break;
 207                 }
 208         }
 209         if (attrtype == -1) {
 210                 syslog(LOG_CRIT, "rad_get_attr: %s", rad_strerror(radh));
 211                 return (PAM_SERVICE_ERR);
 212         }
 213         if (num_msgs == 0) {
 214                 msgs[num_msgs].msg = strdup("(null RADIUS challenge): ");
 215                 if (msgs[num_msgs].msg == NULL) {
 216                         syslog(LOG_CRIT, "Out of memory");
 217                         return (PAM_SERVICE_ERR);
 218                 }
 219                 msgs[num_msgs].msg_style = PAM_TEXT_INFO;
 220                 msg_ptrs[num_msgs] = &msgs[num_msgs];
 221                 num_msgs++;
 222         }
 223         msgs[num_msgs-1].msg_style = PAM_PROMPT_ECHO_ON;
 224         if ((retval = pam_get_item(pamh, PAM_CONV, &item)) != PAM_SUCCESS) {
 225                 syslog(LOG_CRIT, "do_challenge: cannot get PAM_CONV");
 226                 return (retval);
 227         }
 228         conv = (const struct pam_conv *)item;
 229         if ((retval = conv->conv(num_msgs, msg_ptrs, &resp,
 230             conv->appdata_ptr)) != PAM_SUCCESS)
 231                 return (retval);
 232         if (build_access_request(radh, user, resp[num_msgs-1].resp, nas_id,
 233             nas_ipaddr, state, statelen) == -1)
 234                 return (PAM_SERVICE_ERR);
 235         memset(resp[num_msgs-1].resp, 0, strlen(resp[num_msgs-1].resp));
 236         free(resp[num_msgs-1].resp);
 237         free(resp);
 238         while (num_msgs > 0)
 239                 free(msgs[--num_msgs].msg);
 240         return (PAM_SUCCESS);
 241 }
 242
 243 PAM_EXTERN int
 244 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
 245     int argc __unused, const char *argv[] __unused)
 246 {
 247         struct rad_handle *radh;
 248         const char *user, *pass;
 249         const void *tmpuser;
 250         const char *conf_file, *template_user, *nas_id, *nas_ipaddr;
 251         int retval;
 252         int e;
 253
 254         conf_file = openpam_get_option(pamh, PAM_OPT_CONF);
 255         template_user = openpam_get_option(pamh, PAM_OPT_TEMPLATE_USER);
 256         nas_id = openpam_get_option(pamh, PAM_OPT_NAS_ID);
 257         nas_ipaddr = openpam_get_option(pamh, PAM_OPT_NAS_IPADDR);
 258
 259         retval = pam_get_user(pamh, &user, NULL);
 260         if (retval != PAM_SUCCESS)
 261                 return (retval);
 262
 263         PAM_LOG("Got user: %s", user);
 264
 265         retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, PASSWORD_PROMPT);
 266         if (retval != PAM_SUCCESS)
 267                 return (retval);
 268
 269         PAM_LOG("Got password");
 270
 271         radh = rad_open();
 272         if (radh == NULL) {
 273                 syslog(LOG_CRIT, "rad_open failed");
 274                 return (PAM_SERVICE_ERR);
 275         }
 276
 277         PAM_LOG("Radius opened");
 278
 279         if (rad_config(radh, conf_file) == -1) {
 280                 syslog(LOG_ALERT, "rad_config: %s", rad_strerror(radh));
 281                 rad_close(radh);
 282                 return (PAM_SERVICE_ERR);
 283         }
 284
 285         PAM_LOG("Radius config file read");
 286
 287         if (build_access_request(radh, user, pass, nas_id, nas_ipaddr, NULL,
 288             0) == -1) {
 289                 rad_close(radh);
 290                 return (PAM_SERVICE_ERR);
 291         }
 292
 293         PAM_LOG("Radius build access done");
 294
 295         for (;;) {
 296                 switch (rad_send_request(radh)) {
 297
 298                 case RAD_ACCESS_ACCEPT:
 299                         e = do_accept(pamh, radh);
 300                         rad_close(radh);
 301                         if (e == -1)
 302                                 return (PAM_SERVICE_ERR);
 303                         if (template_user != NULL) {
 304
 305                                 PAM_LOG("Trying template user: %s",
 306                                     template_user);
 307
 308                                 /*
 309                                  * If the given user name doesn't exist in
 310                                  * the local password database, change it
 311                                  * to the value given in the "template_user"
 312                                  * option.
 313                                  */
 314                                 retval = pam_get_item(pamh, PAM_USER, &tmpuser);
 315                                 if (retval != PAM_SUCCESS)
 316                                         return (retval);
 317                                 if (getpwnam(tmpuser) == NULL) {
 318                                         pam_set_item(pamh, PAM_USER,
 319                                             template_user);
 320                                         PAM_LOG("Using template user");
 321                                 }
 322
 323                         }
 324                         return (PAM_SUCCESS);
 325
 326                 case RAD_ACCESS_REJECT:
 327                         rad_close(radh);
 328                         PAM_VERBOSE_ERROR("Radius rejection");
 329                         return (PAM_AUTH_ERR);
 330
 331                 case RAD_ACCESS_CHALLENGE:
 332                         retval = do_challenge(pamh, radh, user, nas_id,
 333                             nas_ipaddr);
 334                         if (retval != PAM_SUCCESS) {
 335                                 rad_close(radh);
 336                                 return (retval);
 337                         }
 338                         break;
 339
 340                 case -1:
 341                         syslog(LOG_CRIT, "rad_send_request: %s",
 342                             rad_strerror(radh));
 343                         rad_close(radh);
 344                         PAM_VERBOSE_ERROR("Radius failure");
 345                         return (PAM_AUTHINFO_UNAVAIL);
 346
 347                 default:
 348                         syslog(LOG_CRIT,
 349                             "rad_send_request: unexpected return value");
 350                         rad_close(radh);
 351                         PAM_VERBOSE_ERROR("Radius error");
 352                         return (PAM_SERVICE_ERR);
 353                 }
 354         }
 355 }
 356
 357 PAM_EXTERN int
 358 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
 359     int argc __unused, const char *argv[] __unused)
 360 {
 361
 362         return (PAM_SUCCESS);
 363 }
 364
 365 PAM_MODULE_ENTRY("pam_radius");