lib/pam_module/pam_securetty/pam_securetty.c

   1 /*-
   2  * Copyright (c) 2001 Mark R V Murray
   3  * All rights reserved.
   4  * Copyright (c) 2001 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  * $FreeBSD: src/lib/libpam/modules/pam_securetty/pam_securetty.c,v 1.13 2004/02/10 10:13:21 des Exp $
  37  */
  38
  39 #include <sys/types.h>
  40 #include <sys/stat.h>
  41 #include <pwd.h>
  42 #include <ttyent.h>
  43 #include <string.h>
  44
  45 #define PAM_SM_ACCOUNT
  46
  47 #include <security/pam_appl.h>
  48 #include <security/pam_modules.h>
  49 #include <security/pam_mod_misc.h>
  50
  51 #define TTY_PREFIX      "/dev/"
  52
  53 PAM_EXTERN int
  54 pam_sm_acct_mgmt(pam_handle_t *pamh __unused, int flags __unused,
  55                  int argc __unused, const char *argv[] __unused)
  56 {
  57         struct passwd *pwd;
  58         struct ttyent *ty;
  59         const char *user;
  60         const void *tty;
  61         int pam_err;
  62
  63         pam_err = pam_get_user(pamh, &user, NULL);
  64         if (pam_err != PAM_SUCCESS)
  65                 return (pam_err);
  66         if (user == NULL || (pwd = getpwnam(user)) == NULL)
  67                 return (PAM_SERVICE_ERR);
  68
  69         PAM_LOG("Got user: %s", user);
  70
  71         /* If the user is not root, secure ttys do not apply */
  72         if (pwd->pw_uid != 0)
  73                 return (PAM_SUCCESS);
  74
  75         pam_err = pam_get_item(pamh, PAM_TTY, &tty);
  76         if (pam_err != PAM_SUCCESS)
  77                 return (pam_err);
  78
  79         PAM_LOG("Got TTY: %s", (const char *)tty);
  80
  81         /* Ignore any "/dev/" on the PAM_TTY item */
  82         if (tty != NULL && strncmp(TTY_PREFIX, tty, sizeof(TTY_PREFIX)) == 0) {
  83                 PAM_LOG("WARNING: PAM_TTY starts with " TTY_PREFIX);
  84                 tty = (const char *)tty + sizeof(TTY_PREFIX) - 1;
  85         }
  86
  87         if (tty != NULL && (ty = getttynam(tty)) != NULL &&
  88             (ty->ty_status & TTY_SECURE) != 0)
  89                 return (PAM_SUCCESS);
  90
  91         PAM_VERBOSE_ERROR("Not on secure TTY");
  92         return (PAM_AUTH_ERR);
  93 }
  94
  95 PAM_MODULE_ENTRY("pam_securetty");