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  * $FreeBSD: head/lib/libpam/modules/pam_tacplus/pam_tacplus.c 326219 2017-11-26 02:00:33Z pfg $
  39  */
  40
  41 #include <sys/param.h>
  42
  43 #include <pwd.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46 #include <syslog.h>
  47 #include <taclib.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
  59 typedef int (*set_func)(struct tac_handle *, const char *);
  60
  61 static int       do_item(pam_handle_t *, struct tac_handle *, int,
  62                     set_func, const char *);
  63 static char     *get_msg(struct tac_handle *);
  64 static int       set_msg(struct tac_handle *, const char *);
  65
  66 static int
  67 do_item(pam_handle_t *pamh, struct tac_handle *tach, int item,
  68     set_func func, const char *funcname)
  69 {
  70         int retval;
  71         const void *value;
  72
  73         retval = pam_get_item(pamh, item, &value);
  74         if (retval != PAM_SUCCESS)
  75             return retval;
  76         if (value != NULL && (*func)(tach, (const char *)value) == -1) {
  77                 syslog(LOG_CRIT, "%s: %s", funcname, tac_strerror(tach));
  78                 tac_close(tach);
  79                 return PAM_SERVICE_ERR;
  80         }
  81         return PAM_SUCCESS;
  82 }
  83
  84 static char *
  85 get_msg(struct tac_handle *tach)
  86 {
  87         char *msg;
  88
  89         msg = tac_get_msg(tach);
  90         if (msg == NULL) {
  91                 syslog(LOG_CRIT, "tac_get_msg: %s", tac_strerror(tach));
  92                 tac_close(tach);
  93                 return NULL;
  94         }
  95         return msg;
  96 }
  97
  98 static int
  99 set_msg(struct tac_handle *tach, const char *msg)
 100 {
 101         if (tac_set_msg(tach, msg) == -1) {
 102                 syslog(LOG_CRIT, "tac_set_msg: %s", tac_strerror(tach));
 103                 tac_close(tach);
 104                 return -1;
 105         }
 106         return 0;
 107 }
 108
 109 PAM_EXTERN int
 110 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
 111     int argc __unused, const char *argv[] __unused)
 112 {
 113         int retval;
 114         struct tac_handle *tach;
 115         const char *conf_file, *template_user;
 116
 117         conf_file = openpam_get_option(pamh, PAM_OPT_CONF);
 118         template_user = openpam_get_option(pamh, PAM_OPT_TEMPLATE_USER);
 119
 120         tach = tac_open();
 121         if (tach == NULL) {
 122                 syslog(LOG_CRIT, "tac_open failed");
 123                 return (PAM_SERVICE_ERR);
 124         }
 125         if (tac_config(tach, conf_file) == -1) {
 126                 syslog(LOG_ALERT, "tac_config: %s", tac_strerror(tach));
 127                 tac_close(tach);
 128                 return (PAM_SERVICE_ERR);
 129         }
 130         if (tac_create_authen(tach, TAC_AUTHEN_LOGIN, TAC_AUTHEN_TYPE_ASCII,
 131             TAC_AUTHEN_SVC_LOGIN) == -1) {
 132                 syslog(LOG_CRIT, "tac_create_authen: %s", tac_strerror(tach));
 133                 tac_close(tach);
 134                 return (PAM_SERVICE_ERR);
 135         }
 136
 137         PAM_LOG("Done tac_open() ... tac_close()");
 138
 139         retval = do_item(pamh, tach, PAM_USER, tac_set_user, "tac_set_user");
 140         if (retval != PAM_SUCCESS)
 141                 return (retval);
 142
 143         PAM_LOG("Done user");
 144
 145         retval = do_item(pamh, tach, PAM_TTY, tac_set_port, "tac_set_port");
 146         if (retval != PAM_SUCCESS)
 147                 return (retval);
 148
 149         PAM_LOG("Done tty");
 150
 151         retval = do_item(pamh, tach, PAM_RHOST, tac_set_rem_addr,
 152             "tac_set_rem_addr");
 153         if (retval != PAM_SUCCESS)
 154                 return (retval);
 155
 156         for (;;) {
 157                 char *srvr_msg;
 158                 size_t msg_len;
 159                 const char *user_msg;
 160                 char *data_msg;
 161                 int sflags;
 162                 int status;
 163
 164                 sflags = tac_send_authen(tach);
 165                 if (sflags == -1) {
 166                         syslog(LOG_CRIT, "tac_send_authen: %s",
 167                             tac_strerror(tach));
 168                         tac_close(tach);
 169                         return (PAM_AUTHINFO_UNAVAIL);
 170                 }
 171                 status = TAC_AUTHEN_STATUS(sflags);
 172                 openpam_set_option(pamh, PAM_OPT_ECHO_PASS,
 173                     TAC_AUTHEN_NOECHO(sflags) ? NULL : "");
 174                 switch (status) {
 175
 176                 case TAC_AUTHEN_STATUS_PASS:
 177                         tac_close(tach);
 178                         if (template_user != NULL) {
 179                                 const void *item;
 180                                 const char *user;
 181
 182                                 PAM_LOG("Trying template user: %s",
 183                                     template_user);
 184
 185                                 /*
 186                                  * If the given user name doesn't exist in
 187                                  * the local password database, change it
 188                                  * to the value given in the "template_user"
 189                                  * option.
 190                                  */
 191                                 retval = pam_get_item(pamh, PAM_USER, &item);
 192                                 if (retval != PAM_SUCCESS)
 193                                         return (retval);
 194                                 user = (const char *)item;
 195                                 if (getpwnam(user) == NULL) {
 196                                         pam_set_item(pamh, PAM_USER,
 197                                             template_user);
 198                                         PAM_LOG("Using template user");
 199                                 }
 200                         }
 201                         return (PAM_SUCCESS);
 202
 203                 case TAC_AUTHEN_STATUS_FAIL:
 204                         tac_close(tach);
 205                         PAM_VERBOSE_ERROR("TACACS+ authentication failed");
 206                         return (PAM_AUTH_ERR);
 207
 208                 case TAC_AUTHEN_STATUS_GETUSER:
 209                 case TAC_AUTHEN_STATUS_GETPASS:
 210                         if ((srvr_msg = get_msg(tach)) == NULL)
 211                                 return (PAM_SERVICE_ERR);
 212                         if (status == TAC_AUTHEN_STATUS_GETUSER)
 213                                 retval = pam_get_user(pamh, &user_msg,
 214                                     *srvr_msg ? srvr_msg : NULL);
 215                         else if (status == TAC_AUTHEN_STATUS_GETPASS)
 216                                 retval = pam_get_authtok(pamh,
 217                                     PAM_AUTHTOK, &user_msg,
 218                                     *srvr_msg ? srvr_msg : "Password:");
 219                         free(srvr_msg);
 220                         if (retval != PAM_SUCCESS) {
 221                                 /* XXX - send a TACACS+ abort packet */
 222                                 tac_close(tach);
 223                                 return (retval);
 224                         }
 225                         if (set_msg(tach, user_msg) == -1)
 226                                 return (PAM_SERVICE_ERR);
 227                         break;
 228
 229                 case TAC_AUTHEN_STATUS_GETDATA:
 230                         if ((srvr_msg = get_msg(tach)) == NULL)
 231                                 return (PAM_SERVICE_ERR);
 232                         retval = pam_prompt(pamh,
 233                             openpam_get_option(pamh, PAM_OPT_ECHO_PASS) ?
 234                             PAM_PROMPT_ECHO_ON : PAM_PROMPT_ECHO_OFF,
 235                             &data_msg, "%s", *srvr_msg ? srvr_msg : "Data:");
 236                         free(srvr_msg);
 237                         if (retval != PAM_SUCCESS) {
 238                                 /* XXX - send a TACACS+ abort packet */
 239                                 tac_close(tach);
 240                                 return (retval);
 241                         }
 242                         retval = set_msg(tach, data_msg);
 243                         memset(data_msg, 0, strlen(data_msg));
 244                         free(data_msg);
 245                         if (retval == -1)
 246                                 return (PAM_SERVICE_ERR);
 247                         break;
 248
 249                 case TAC_AUTHEN_STATUS_ERROR:
 250                         srvr_msg = (char *)tac_get_data(tach, &msg_len);
 251                         if (srvr_msg != NULL && msg_len != 0) {
 252                                 syslog(LOG_CRIT, "tac_send_authen:"
 253                                     " server detected error: %s", srvr_msg);
 254                                 free(srvr_msg);
 255                         }
 256                         else
 257                                 syslog(LOG_CRIT,
 258                                     "tac_send_authen: server detected error");
 259                         tac_close(tach);
 260                         return (PAM_AUTHINFO_UNAVAIL);
 261                         break;
 262
 263                 case TAC_AUTHEN_STATUS_RESTART:
 264                 case TAC_AUTHEN_STATUS_FOLLOW:
 265                 default:
 266                         syslog(LOG_CRIT,
 267                             "tac_send_authen: unexpected status %#x", status);
 268                         tac_close(tach);
 269                         return (PAM_AUTHINFO_UNAVAIL);
 270                 }
 271         }
 272 }
 273
 274 PAM_EXTERN int
 275 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
 276     int argc __unused, const char *argv[] __unused)
 277 {
 278
 279         return (PAM_IGNORE);
 280 }
 281
 282 PAM_MODULE_ENTRY("pam_tacplus");