lib/pam_module/pam_guest/pam_guest.c

   1 /*-
   2  * Copyright (c) 2003 Networks Associates Technology, Inc.
   3  * All rights reserved.
   4  *
   5  * Portions of this software were developed for the FreeBSD Project by
   6  * ThinkSec AS and NAI Labs, the Security Research Division of Network
   7  * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
   8  * ("CBOSS"), as part of the DARPA CHATS research program.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. The name of the author may not be used to endorse or promote
  19  *    products derived from this software without specific prior written
  20  *    permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * $FreeBSD: src/lib/libpam/modules/pam_guest/pam_guest.c,v 1.1 2003/05/31 16:52:58 des Exp $
  35  */
  36
  37 #include <string.h>
  38
  39 #define PAM_SM_AUTH
  40
  41 #include <security/pam_appl.h>
  42 #include <security/pam_modules.h>
  43 #include <security/openpam.h>
  44
  45 #define DEFAULT_GUESTS  "guest"
  46
  47 static int
  48 lookup(const char *str, const char *list)
  49 {
  50         const char *next;
  51         size_t len;
  52
  53         len = strlen(str);
  54         while (*list != '\0') {
  55                 while (*list == ',')
  56                         ++list;
  57                 if ((next = strchr(list, ',')) == NULL)
  58                         next = strchr(list, '\0');
  59                 if (next - list == (ptrdiff_t)len &&
  60                     strncmp(list, str, len) == 0)
  61                         return (1);
  62                 list = next;
  63         }
  64         return (0);
  65 }
  66
  67 PAM_EXTERN int
  68 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
  69                     int argc __unused, const char *argv[] __unused)
  70 {
  71         const char *authtok, *guests, *user;
  72         int err, is_guest;
  73
  74         /* get target account */
  75         if (pam_get_user(pamh, &user, NULL) != PAM_SUCCESS || user == NULL)
  76                 return (PAM_AUTH_ERR);
  77
  78         /* get list of guest logins */
  79         if ((guests = openpam_get_option(pamh, "guests")) == NULL)
  80                 guests = DEFAULT_GUESTS;
  81
  82         /* check if the target account is on the list */
  83         is_guest = lookup(user, guests);
  84
  85         /* check password */
  86         if (!openpam_get_option(pamh, "nopass")) {
  87                 err = pam_get_authtok(pamh, PAM_AUTHTOK, &authtok, NULL);
  88                 if (err != PAM_SUCCESS)
  89                         return (err);
  90                 if (openpam_get_option(pamh, "pass_is_user") &&
  91                     strcmp(user, authtok) != 0)
  92                         return (PAM_AUTH_ERR);
  93                 if (openpam_get_option(pamh, "pass_as_ruser"))
  94                         pam_set_item(pamh, PAM_RUSER, authtok);
  95         }
  96
  97         /* done */
  98         if (is_guest) {
  99                 pam_setenv(pamh, "GUEST", user, 1);
 100                 return (PAM_SUCCESS);
 101         }
 102         return (PAM_AUTH_ERR);
 103 }
 104
 105 PAM_EXTERN int
 106 pam_sm_setcred(pam_handle_t * pamh __unused, int flags __unused,
 107                int argc __unused, const char *argv[] __unused)
 108 {
 109
 110         return (PAM_SUCCESS);
 111 }
 112
 113 PAM_MODULE_ENTRY("pam_guest");