lib/libpam/modules/pam_group/pam_group.c

   1 /*      $NetBSD: pam_group.c,v 1.11 2009/02/11 18:38:56 christos Exp $  */
   2
   3 /*-
   4  * Copyright (c) 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 #ifdef __FreeBSD__
  39 __FBSDID("$FreeBSD: src/lib/libpam/modules/pam_group/pam_group.c,v 1.4 2003/12/11 13:55:15 des Exp $");
  40 #else
  41 __RCSID("$NetBSD: pam_group.c,v 1.11 2009/02/11 18:38:56 christos Exp $");
  42 #endif
  43
  44 #include <sys/types.h>
  45
  46 #include <grp.h>
  47 #include <pwd.h>
  48 #include <stdarg.h>
  49 #include <stdio.h>
  50 #include <string.h>
  51 #include <stdlib.h>
  52 #include <unistd.h>
  53 #include <login_cap.h>
  54
  55 #define PAM_SM_AUTH
  56
  57 #include <security/pam_appl.h>
  58 #include <security/pam_modules.h>
  59 #include <security/pam_mod_misc.h>
  60 #include <security/openpam.h>
  61
  62 static int authenticate(pam_handle_t *, struct passwd *, int);
  63
  64 #define PASSWORD_PROMPT         "%s's password:"
  65
  66 PAM_EXTERN int
  67 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
  68     int argc __unused, const char *argv[] __unused)
  69 {
  70         const char *group, *user;
  71         const void *ruser;
  72         char *const *list;
  73         struct passwd *pwd, pwres;
  74         struct group *grp, grres;
  75         int pam_err, auth;
  76         char *promptresp = NULL;
  77         char pwbuf[1024];
  78         char grbuf[1024];
  79
  80         /* get target account */
  81         if (pam_get_user(pamh, &user, NULL) != PAM_SUCCESS ||
  82             user == NULL ||
  83             getpwnam_r(user, &pwres, pwbuf, sizeof(pwbuf), &pwd) != 0 ||
  84             pwd == NULL)
  85                 return (PAM_AUTH_ERR);
  86         if (pwd->pw_uid != 0 && openpam_get_option(pamh, "root_only"))
  87                 return (PAM_IGNORE);
  88
  89         /* get applicant */
  90         if (pam_get_item(pamh, PAM_RUSER, &ruser) != PAM_SUCCESS ||
  91             ruser == NULL ||
  92             getpwnam_r(ruser, &pwres, pwbuf, sizeof(pwbuf), &pwd) != 0 ||
  93             pwd == NULL)
  94                 return (PAM_AUTH_ERR);
  95
  96         auth = openpam_get_option(pamh, "authenticate") != NULL;
  97
  98         /* get regulating group */
  99         if ((group = openpam_get_option(pamh, "group")) == NULL)
 100                 group = "wheel";
 101         if (getgrnam_r(group, &grres, grbuf, sizeof(grbuf), &grp) != 0 ||
 102             grp == NULL || grp->gr_mem == NULL)
 103                 goto failed;
 104
 105         /* check if the group is empty */
 106         if (*grp->gr_mem == NULL)
 107                 goto failed;
 108
 109         /* check membership */
 110         if (pwd->pw_gid == grp->gr_gid)
 111                 goto found;
 112         for (list = grp->gr_mem; *list != NULL; ++list)
 113                 if (strcmp(*list, pwd->pw_name) == 0)
 114                         goto found;
 115
 116  not_found:
 117         if (openpam_get_option(pamh, "deny"))
 118                 return (PAM_SUCCESS);
 119         if (!auth) {
 120                 pam_err = pam_prompt(pamh, PAM_ERROR_MSG, &promptresp,
 121                     "%s: You are not listed in the correct secondary group"
 122                     " (%s) to %s %s.", getprogname(), group, getprogname(),
 123                     user);
 124                 if (pam_err == PAM_SUCCESS && promptresp)
 125                         free(promptresp);
 126         }
 127         return (PAM_AUTH_ERR);
 128  found:
 129         if (auth)
 130                 if ((pam_err = authenticate(pamh, pwd, flags)) != PAM_SUCCESS)
 131                         return pam_err;
 132
 133         if (openpam_get_option(pamh, "deny"))
 134                 return (PAM_AUTH_ERR);
 135         return (PAM_SUCCESS);
 136  failed:
 137         if (openpam_get_option(pamh, "fail_safe"))
 138                 goto found;
 139         else
 140                 goto not_found;
 141 }
 142
 143 PAM_EXTERN int
 144 pam_sm_setcred(pam_handle_t * pamh __unused, int flags __unused,
 145     int argc __unused, const char *argv[] __unused)
 146 {
 147
 148         return (PAM_SUCCESS);
 149 }
 150
 151 static int
 152 authenticate(pam_handle_t *pamh, struct passwd *pwd, int flags)
 153 {
 154         int retval;
 155         login_cap_t *lc;
 156         const char *pass;
 157         char password_prompt[80];
 158
 159         (void) snprintf(password_prompt, sizeof(password_prompt),
 160                     PASSWORD_PROMPT, pwd->pw_name);
 161         lc = login_getpwclass(pwd);
 162         retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, password_prompt);
 163         login_close(lc);
 164
 165         if (retval != PAM_SUCCESS)
 166                 return retval;
 167         PAM_LOG("Got password");
 168         if (strcmp(crypt(pass, pwd->pw_passwd), pwd->pw_passwd) == 0)
 169                 return PAM_SUCCESS;
 170
 171         PAM_VERBOSE_ERROR("UNIX authentication refused");
 172         return PAM_AUTH_ERR;
 173 }
 174
 175
 176 PAM_MODULE_ENTRY("pam_group");