lib/libpam/modules/pam_tacplus/pam_tacplus.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   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 __FBSDID("$FreeBSD$");
  41
  42 #include <sys/param.h>
  43
  44 #include <pwd.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include <syslog.h>
  48 #include <taclib.h>
  49 #include <unistd.h>
  50
  51 #define PAM_SM_AUTH
  52
  53 #include <security/pam_appl.h>
  54 #include <security/pam_modules.h>
  55 #include <security/pam_mod_misc.h>
  56
  57 #define PAM_OPT_CONF            "conf"
  58 #define PAM_OPT_TEMPLATE_USER   "template_user"
  59
  60 typedef int (*set_func)(struct tac_handle *, const char *);
  61
  62 static int       do_item(pam_handle_t *, struct tac_handle *, int,
  63                     set_func, const char *);
  64 static char     *get_msg(struct tac_handle *);
  65 static int       set_msg(struct tac_handle *, const char *);
  66
  67 static int
  68 do_item(pam_handle_t *pamh, struct tac_handle *tach, int item,
  69     set_func func, const char *funcname)
  70 {
  71         int retval;
  72         const void *value;
  73
  74         retval = pam_get_item(pamh, item, &value);
  75         if (retval != PAM_SUCCESS)
  76             return retval;
  77         if (value != NULL && (*func)(tach, (const char *)value) == -1) {
  78                 syslog(LOG_CRIT, "%s: %s", funcname, tac_strerror(tach));
  79                 tac_close(tach);
  80                 return PAM_SERVICE_ERR;
  81         }
  82         return PAM_SUCCESS;
  83 }
  84
  85 static char *
  86 get_msg(struct tac_handle *tach)
  87 {
  88         char *msg;
  89
  90         msg = tac_get_msg(tach);
  91         if (msg == NULL) {
  92                 syslog(LOG_CRIT, "tac_get_msg: %s", tac_strerror(tach));
  93                 tac_close(tach);
  94                 return NULL;
  95         }
  96         return msg;
  97 }
  98
  99 static int
 100 set_msg(struct tac_handle *tach, const char *msg)
 101 {
 102         if (tac_set_msg(tach, msg) == -1) {
 103                 syslog(LOG_CRIT, "tac_set_msg: %s", tac_strerror(tach));
 104                 tac_close(tach);
 105                 return -1;
 106         }
 107         return 0;
 108 }
 109
 110 PAM_EXTERN int
 111 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
 112     int argc __unused, const char *argv[] __unused)
 113 {
 114         int retval;
 115         struct tac_handle *tach;
 116         const char *conf_file, *template_user;
 117
 118         conf_file = openpam_get_option(pamh, PAM_OPT_CONF);
 119         template_user = openpam_get_option(pamh, PAM_OPT_TEMPLATE_USER);
 120
 121         tach = tac_open();
 122         if (tach == NULL) {
 123                 syslog(LOG_CRIT, "tac_open failed");
 124                 return (PAM_SERVICE_ERR);
 125         }
 126         if (tac_config(tach, conf_file) == -1) {
 127                 syslog(LOG_ALERT, "tac_config: %s", tac_strerror(tach));
 128                 tac_close(tach);
 129                 return (PAM_SERVICE_ERR);
 130         }
 131         if (tac_create_authen(tach, TAC_AUTHEN_LOGIN, TAC_AUTHEN_TYPE_ASCII,
 132             TAC_AUTHEN_SVC_LOGIN) == -1) {
 133                 syslog(LOG_CRIT, "tac_create_authen: %s", tac_strerror(tach));
 134                 tac_close(tach);
 135                 return (PAM_SERVICE_ERR);
 136         }
 137
 138         PAM_LOG("Done tac_open() ... tac_close()");
 139
 140         retval = do_item(pamh, tach, PAM_USER, tac_set_user, "tac_set_user");
 141         if (retval != PAM_SUCCESS)
 142                 return (retval);
 143
 144         PAM_LOG("Done user");
 145
 146         retval = do_item(pamh, tach, PAM_TTY, tac_set_port, "tac_set_port");
 147         if (retval != PAM_SUCCESS)
 148                 return (retval);
 149
 150         PAM_LOG("Done tty");
 151
 152         retval = do_item(pamh, tach, PAM_RHOST, tac_set_rem_addr,
 153             "tac_set_rem_addr");
 154         if (retval != PAM_SUCCESS)
 155                 return (retval);
 156
 157         for (;;) {
 158                 char *srvr_msg;
 159                 size_t msg_len;
 160                 const char *user_msg;
 161                 char *data_msg;
 162                 int sflags;
 163                 int status;
 164
 165                 sflags = tac_send_authen(tach);
 166                 if (sflags == -1) {
 167                         syslog(LOG_CRIT, "tac_send_authen: %s",
 168                             tac_strerror(tach));
 169                         tac_close(tach);
 170                         return (PAM_AUTHINFO_UNAVAIL);
 171                 }
 172                 status = TAC_AUTHEN_STATUS(sflags);
 173                 openpam_set_option(pamh, PAM_OPT_ECHO_PASS,
 174                     TAC_AUTHEN_NOECHO(sflags) ? NULL : "");
 175                 switch (status) {
 176
 177                 case TAC_AUTHEN_STATUS_PASS:
 178                         tac_close(tach);
 179                         if (template_user != NULL) {
 180                                 const void *item;
 181                                 const char *user;
 182
 183                                 PAM_LOG("Trying template user: %s",
 184                                     template_user);
 185
 186                                 /*
 187                                  * If the given user name doesn't exist in
 188                                  * the local password database, change it
 189                                  * to the value given in the "template_user"
 190                                  * option.
 191                                  */
 192                                 retval = pam_get_item(pamh, PAM_USER, &item);
 193                                 if (retval != PAM_SUCCESS)
 194                                         return (retval);
 195                                 user = (const char *)item;
 196                                 if (getpwnam(user) == NULL) {
 197                                         pam_set_item(pamh, PAM_USER,
 198                                             template_user);
 199                                         PAM_LOG("Using template user");
 200                                 }
 201                         }
 202                         return (PAM_SUCCESS);
 203
 204                 case TAC_AUTHEN_STATUS_FAIL:
 205                         tac_close(tach);
 206                         PAM_VERBOSE_ERROR("TACACS+ authentication failed");
 207                         return (PAM_AUTH_ERR);
 208
 209                 case TAC_AUTHEN_STATUS_GETUSER:
 210                 case TAC_AUTHEN_STATUS_GETPASS:
 211                         if ((srvr_msg = get_msg(tach)) == NULL)
 212                                 return (PAM_SERVICE_ERR);
 213                         if (status == TAC_AUTHEN_STATUS_GETUSER)
 214                                 retval = pam_get_user(pamh, &user_msg,
 215                                     *srvr_msg ? srvr_msg : NULL);
 216                         else if (status == TAC_AUTHEN_STATUS_GETPASS)
 217                                 retval = pam_get_authtok(pamh,
 218                                     PAM_AUTHTOK, &user_msg,
 219                                     *srvr_msg ? srvr_msg : "Password:");
 220                         free(srvr_msg);
 221                         if (retval != PAM_SUCCESS) {
 222                                 /* XXX - send a TACACS+ abort packet */
 223                                 tac_close(tach);
 224                                 return (retval);
 225                         }
 226                         if (set_msg(tach, user_msg) == -1)
 227                                 return (PAM_SERVICE_ERR);
 228                         break;
 229
 230                 case TAC_AUTHEN_STATUS_GETDATA:
 231                         if ((srvr_msg = get_msg(tach)) == NULL)
 232                                 return (PAM_SERVICE_ERR);
 233                         retval = pam_prompt(pamh,
 234                             openpam_get_option(pamh, PAM_OPT_ECHO_PASS) ?
 235                             PAM_PROMPT_ECHO_ON : PAM_PROMPT_ECHO_OFF,
 236                             &data_msg, "%s", *srvr_msg ? srvr_msg : "Data:");
 237                         free(srvr_msg);
 238                         if (retval != PAM_SUCCESS) {
 239                                 /* XXX - send a TACACS+ abort packet */
 240                                 tac_close(tach);
 241                                 return (retval);
 242                         }
 243                         retval = set_msg(tach, data_msg);
 244                         memset(data_msg, 0, strlen(data_msg));
 245                         free(data_msg);
 246                         if (retval == -1)
 247                                 return (PAM_SERVICE_ERR);
 248                         break;
 249
 250                 case TAC_AUTHEN_STATUS_ERROR:
 251                         srvr_msg = (char *)tac_get_data(tach, &msg_len);
 252                         if (srvr_msg != NULL && msg_len != 0) {
 253                                 syslog(LOG_CRIT, "tac_send_authen:"
 254                                     " server detected error: %s", srvr_msg);
 255                                 free(srvr_msg);
 256                         }
 257                         else
 258                                 syslog(LOG_CRIT,
 259                                     "tac_send_authen: server detected error");
 260                         tac_close(tach);
 261                         return (PAM_AUTHINFO_UNAVAIL);
 262                         break;
 263
 264                 case TAC_AUTHEN_STATUS_RESTART:
 265                 case TAC_AUTHEN_STATUS_FOLLOW:
 266                 default:
 267                         syslog(LOG_CRIT,
 268                             "tac_send_authen: unexpected status %#x", status);
 269                         tac_close(tach);
 270                         return (PAM_AUTHINFO_UNAVAIL);
 271                 }
 272         }
 273 }
 274
 275 PAM_EXTERN int
 276 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
 277     int argc __unused, const char *argv[] __unused)
 278 {
 279
 280         return (PAM_IGNORE);
 281 }
 282
 283 PAM_MODULE_ENTRY("pam_tacplus");