lib/libpam/modules/pam_tacplus/pam_tacplus.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
  37 #include <sys/cdefs.h>
  38 __FBSDID("$FreeBSD$");
  39
  40 #include <sys/param.h>
  41
  42 #include <pwd.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45 #include <syslog.h>
  46 #include <taclib.h>
  47 #include <unistd.h>
  48
  49 #define PAM_SM_AUTH
  50
  51 #include <security/pam_appl.h>
  52 #include <security/pam_modules.h>
  53 #include <security/pam_mod_misc.h>
  54
  55 #define PAM_OPT_CONF            "conf"
  56 #define PAM_OPT_TEMPLATE_USER   "template_user"
  57
  58 typedef int (*set_func)(struct tac_handle *, const char *);
  59
  60 static int       do_item(pam_handle_t *, struct tac_handle *, int,
  61                     set_func, const char *);
  62 static char     *get_msg(struct tac_handle *);
  63 static int       set_msg(struct tac_handle *, const char *);
  64
  65 static int
  66 do_item(pam_handle_t *pamh, struct tac_handle *tach, int item,
  67     set_func func, const char *funcname)
  68 {
  69         int retval;
  70         const void *value;
  71
  72         retval = pam_get_item(pamh, item, &value);
  73         if (retval != PAM_SUCCESS)
  74             return retval;
  75         if (value != NULL && (*func)(tach, (const char *)value) == -1) {
  76                 syslog(LOG_CRIT, "%s: %s", funcname, tac_strerror(tach));
  77                 tac_close(tach);
  78                 return PAM_SERVICE_ERR;
  79         }
  80         return PAM_SUCCESS;
  81 }
  82
  83 static char *
  84 get_msg(struct tac_handle *tach)
  85 {
  86         char *msg;
  87
  88         msg = tac_get_msg(tach);
  89         if (msg == NULL) {
  90                 syslog(LOG_CRIT, "tac_get_msg: %s", tac_strerror(tach));
  91                 tac_close(tach);
  92                 return NULL;
  93         }
  94         return msg;
  95 }
  96
  97 static int
  98 set_msg(struct tac_handle *tach, const char *msg)
  99 {
 100         if (tac_set_msg(tach, msg) == -1) {
 101                 syslog(LOG_CRIT, "tac_set_msg: %s", tac_strerror(tach));
 102                 tac_close(tach);
 103                 return -1;
 104         }
 105         return 0;
 106 }
 107
 108 PAM_EXTERN int
 109 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
 110     int argc __unused, const char *argv[] __unused)
 111 {
 112         int retval;
 113         struct tac_handle *tach;
 114         const char *conf_file, *template_user;
 115
 116         conf_file = openpam_get_option(pamh, PAM_OPT_CONF);
 117         template_user = openpam_get_option(pamh, PAM_OPT_TEMPLATE_USER);
 118
 119         tach = tac_open();
 120         if (tach == NULL) {
 121                 syslog(LOG_CRIT, "tac_open failed");
 122                 return (PAM_SERVICE_ERR);
 123         }
 124         if (tac_config(tach, conf_file) == -1) {
 125                 syslog(LOG_ALERT, "tac_config: %s", tac_strerror(tach));
 126                 tac_close(tach);
 127                 return (PAM_SERVICE_ERR);
 128         }
 129         if (tac_create_authen(tach, TAC_AUTHEN_LOGIN, TAC_AUTHEN_TYPE_ASCII,
 130             TAC_AUTHEN_SVC_LOGIN) == -1) {
 131                 syslog(LOG_CRIT, "tac_create_authen: %s", tac_strerror(tach));
 132                 tac_close(tach);
 133                 return (PAM_SERVICE_ERR);
 134         }
 135
 136         PAM_LOG("Done tac_open() ... tac_close()");
 137
 138         retval = do_item(pamh, tach, PAM_USER, tac_set_user, "tac_set_user");
 139         if (retval != PAM_SUCCESS)
 140                 return (retval);
 141
 142         PAM_LOG("Done user");
 143
 144         retval = do_item(pamh, tach, PAM_TTY, tac_set_port, "tac_set_port");
 145         if (retval != PAM_SUCCESS)
 146                 return (retval);
 147
 148         PAM_LOG("Done tty");
 149
 150         retval = do_item(pamh, tach, PAM_RHOST, tac_set_rem_addr,
 151             "tac_set_rem_addr");
 152         if (retval != PAM_SUCCESS)
 153                 return (retval);
 154
 155         for (;;) {
 156                 char *srvr_msg;
 157                 size_t msg_len;
 158                 const char *user_msg;
 159                 char *data_msg;
 160                 int sflags;
 161                 int status;
 162
 163                 sflags = tac_send_authen(tach);
 164                 if (sflags == -1) {
 165                         syslog(LOG_CRIT, "tac_send_authen: %s",
 166                             tac_strerror(tach));
 167                         tac_close(tach);
 168                         return (PAM_AUTHINFO_UNAVAIL);
 169                 }
 170                 status = TAC_AUTHEN_STATUS(sflags);
 171                 openpam_set_option(pamh, PAM_OPT_ECHO_PASS,
 172                     TAC_AUTHEN_NOECHO(sflags) ? NULL : "");
 173                 switch (status) {
 174
 175                 case TAC_AUTHEN_STATUS_PASS:
 176                         tac_close(tach);
 177                         if (template_user != NULL) {
 178                                 const void *item;
 179                                 const char *user;
 180
 181                                 PAM_LOG("Trying template user: %s",
 182                                     template_user);
 183
 184                                 /*
 185                                  * If the given user name doesn't exist in
 186                                  * the local password database, change it
 187                                  * to the value given in the "template_user"
 188                                  * option.
 189                                  */
 190                                 retval = pam_get_item(pamh, PAM_USER, &item);
 191                                 if (retval != PAM_SUCCESS)
 192                                         return (retval);
 193                                 user = (const char *)item;
 194                                 if (getpwnam(user) == NULL) {
 195                                         pam_set_item(pamh, PAM_USER,
 196                                             template_user);
 197                                         PAM_LOG("Using template user");
 198                                 }
 199                         }
 200                         return (PAM_SUCCESS);
 201
 202                 case TAC_AUTHEN_STATUS_FAIL:
 203                         tac_close(tach);
 204                         PAM_VERBOSE_ERROR("TACACS+ authentication failed");
 205                         return (PAM_AUTH_ERR);
 206
 207                 case TAC_AUTHEN_STATUS_GETUSER:
 208                 case TAC_AUTHEN_STATUS_GETPASS:
 209                         if ((srvr_msg = get_msg(tach)) == NULL)
 210                                 return (PAM_SERVICE_ERR);
 211                         if (status == TAC_AUTHEN_STATUS_GETUSER)
 212                                 retval = pam_get_user(pamh, &user_msg,
 213                                     *srvr_msg ? srvr_msg : NULL);
 214                         else if (status == TAC_AUTHEN_STATUS_GETPASS)
 215                                 retval = pam_get_authtok(pamh,
 216                                     PAM_AUTHTOK, &user_msg,
 217                                     *srvr_msg ? srvr_msg : "Password:");
 218                         free(srvr_msg);
 219                         if (retval != PAM_SUCCESS) {
 220                                 /* XXX - send a TACACS+ abort packet */
 221                                 tac_close(tach);
 222                                 return (retval);
 223                         }
 224                         if (set_msg(tach, user_msg) == -1)
 225                                 return (PAM_SERVICE_ERR);
 226                         break;
 227
 228                 case TAC_AUTHEN_STATUS_GETDATA:
 229                         if ((srvr_msg = get_msg(tach)) == NULL)
 230                                 return (PAM_SERVICE_ERR);
 231                         retval = pam_prompt(pamh,
 232                             openpam_get_option(pamh, PAM_OPT_ECHO_PASS) ?
 233                             PAM_PROMPT_ECHO_ON : PAM_PROMPT_ECHO_OFF,
 234                             &data_msg, "%s", *srvr_msg ? srvr_msg : "Data:");
 235                         free(srvr_msg);
 236                         if (retval != PAM_SUCCESS) {
 237                                 /* XXX - send a TACACS+ abort packet */
 238                                 tac_close(tach);
 239                                 return (retval);
 240                         }
 241                         retval = set_msg(tach, data_msg);
 242                         memset(data_msg, 0, strlen(data_msg));
 243                         free(data_msg);
 244                         if (retval == -1)
 245                                 return (PAM_SERVICE_ERR);
 246                         break;
 247
 248                 case TAC_AUTHEN_STATUS_ERROR:
 249                         srvr_msg = (char *)tac_get_data(tach, &msg_len);
 250                         if (srvr_msg != NULL && msg_len != 0) {
 251                                 syslog(LOG_CRIT, "tac_send_authen:"
 252                                     " server detected error: %s", srvr_msg);
 253                                 free(srvr_msg);
 254                         }
 255                         else
 256                                 syslog(LOG_CRIT,
 257                                     "tac_send_authen: server detected error");
 258                         tac_close(tach);
 259                         return (PAM_AUTHINFO_UNAVAIL);
 260                         break;
 261
 262                 case TAC_AUTHEN_STATUS_RESTART:
 263                 case TAC_AUTHEN_STATUS_FOLLOW:
 264                 default:
 265                         syslog(LOG_CRIT,
 266                             "tac_send_authen: unexpected status %#x", status);
 267                         tac_close(tach);
 268                         return (PAM_AUTHINFO_UNAVAIL);
 269                 }
 270         }
 271 }
 272
 273 PAM_EXTERN int
 274 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
 275     int argc __unused, const char *argv[] __unused)
 276 {
 277
 278         return (PAM_IGNORE);
 279 }
 280
 281 PAM_MODULE_ENTRY("pam_tacplus");