lib/pam_module/pam_group/pam_group.c

   1 /*-
   2  * Copyright (c) 2003 Networks Associates Technology, Inc.
   3  * Copyright (c) 2004-2011 Dag-Erling Smørgrav
   4  * All rights reserved.
   5  *
   6  * Portions of this software were developed for the FreeBSD Project by
   7  * ThinkSec AS and NAI Labs, the Security Research Division of Network
   8  * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
   9  * ("CBOSS"), as part of the DARPA CHATS research program.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. The name of the author may not be used to endorse or promote
  20  *    products derived from this software without specific prior written
  21  *    permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  *
  35  * $FreeBSD: src/lib/libpam/modules/pam_group/pam_group.c,v 1.6 2011/03/12 11:26:37 des Exp $
  36  */
  37
  38 #include <sys/types.h>
  39
  40 #include <grp.h>
  41 #include <pwd.h>
  42 #include <stdarg.h>
  43 #include <stdio.h>
  44 #include <string.h>
  45 #include <syslog.h>
  46 #include <unistd.h>
  47
  48 #define PAM_SM_AUTH
  49
  50 #include <security/pam_appl.h>
  51 #include <security/pam_modules.h>
  52 #include <security/openpam.h>
  53
  54
  55 PAM_EXTERN int
  56 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
  57                     int argc __unused, const char *argv[] __unused)
  58 {
  59         int local, remote;
  60         const char *group, *user;
  61         const void *ruser;
  62         char *const *list;
  63         struct passwd *pwd;
  64         struct group *grp;
  65
  66         /* get target account */
  67         if (pam_get_user(pamh, &user, NULL) != PAM_SUCCESS ||
  68             user == NULL || (pwd = getpwnam(user)) == NULL)
  69                 return (PAM_AUTH_ERR);
  70         if (pwd->pw_uid != 0 && openpam_get_option(pamh, "root_only"))
  71                 return (PAM_IGNORE);
  72
  73         /* check local / remote */
  74         local = openpam_get_option(pamh, "luser") ? 1 : 0;
  75         remote = openpam_get_option(pamh, "ruser") ? 1 : 0;
  76         if (local && remote) {
  77                 openpam_log(PAM_LOG_ERROR, "(pam_group) "
  78                     "the luser and ruser options are mutually exclusive");
  79                 return (PAM_SERVICE_ERR);
  80         } else if (local) {
  81                 /* we already have the correct struct passwd */
  82         } else {
  83                 if (!remote)
  84                         openpam_log(PAM_LOG_NOTICE, "(pam_group) "
  85                             "neither luser nor ruser specified, assuming ruser");
  86                 /* default / historical behavior */
  87                 if (pam_get_item(pamh, PAM_RUSER, &ruser) != PAM_SUCCESS ||
  88                     ruser == NULL || (pwd = getpwnam(ruser)) == NULL)
  89                         return (PAM_AUTH_ERR);
  90         }
  91
  92         /* get regulating group */
  93         if ((group = openpam_get_option(pamh, "group")) == NULL)
  94                 group = "wheel";
  95         if ((grp = getgrnam(group)) == NULL || grp->gr_mem == NULL)
  96                 goto failed;
  97
  98         /* check if the group is empty */
  99         if (*grp->gr_mem == NULL)
 100                 goto failed;
 101
 102         /* check membership */
 103         if (pwd->pw_gid == grp->gr_gid)
 104                 goto found;
 105         for (list = grp->gr_mem; *list != NULL; ++list)
 106                 if (strcmp(*list, pwd->pw_name) == 0)
 107                         goto found;
 108
 109  not_found:
 110         if (openpam_get_option(pamh, "deny"))
 111                 return (PAM_SUCCESS);
 112         return (PAM_AUTH_ERR);
 113  found:
 114         if (openpam_get_option(pamh, "deny"))
 115                 return (PAM_AUTH_ERR);
 116         return (PAM_SUCCESS);
 117  failed:
 118         if (openpam_get_option(pamh, "fail_safe"))
 119                 goto found;
 120         else
 121                 goto not_found;
 122 }
 123
 124 PAM_EXTERN int
 125 pam_sm_setcred(pam_handle_t * pamh __unused, int flags __unused,
 126                int argc __unused, const char *argv[] __unused)
 127 {
 128
 129         return (PAM_SUCCESS);
 130 }
 131
 132 PAM_MODULE_ENTRY("pam_group");