lib/libpam/modules/pam_self/pam_self.c

   1 /*      $NetBSD: pam_self.c,v 1.4 2005/04/19 03:15:36 christos Exp $    */
   2
   3 /*-
   4  * Copyright (c) 2001 Mark R V Murray
   5  * All rights reserved.
   6  * Copyright (c) 2001,2002 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
  39 #include <sys/cdefs.h>
  40 #ifdef __FreeBSD__
  41 __FBSDID("$FreeBSD: src/lib/libpam/modules/pam_self/pam_self.c,v 1.9 2002/04/12 22:27:24 des Exp $");
  42 #else
  43 __RCSID("$NetBSD: pam_self.c,v 1.4 2005/04/19 03:15:36 christos Exp $");
  44 #endif
  45
  46 #define _BSD_SOURCE
  47
  48 #include <pwd.h>
  49 #include <unistd.h>
  50
  51 #define PAM_SM_AUTH
  52
  53 #include <security/pam_appl.h>
  54 #include <security/pam_modules.h>
  55 #include <security/pam_mod_misc.h>
  56
  57 #define OPT_ALLOW_ROOT "allow_root"
  58
  59 PAM_EXTERN int
  60 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
  61     int argc __unused, const char *argv[] __unused)
  62 {
  63         struct passwd *pwd, pwres;
  64         const char *luser;
  65         int pam_err;
  66         uid_t uid;
  67         char pwbuf[1024];
  68
  69         pam_err = pam_get_user(pamh, &luser, NULL);
  70         if (pam_err != PAM_SUCCESS)
  71                 return (pam_err);
  72         if (luser == NULL ||
  73             getpwnam_r(luser, &pwres, pwbuf, sizeof(pwbuf), &pwd) != 0 ||
  74             pwd == NULL)
  75                 return (PAM_AUTH_ERR);
  76
  77         uid = getuid();
  78         if (uid == 0 && !openpam_get_option(pamh, OPT_ALLOW_ROOT))
  79                 return (PAM_AUTH_ERR);
  80
  81         if (uid == (uid_t)pwd->pw_uid)
  82                 return (PAM_SUCCESS);
  83
  84         PAM_VERBOSE_ERROR("Refused; source and target users differ");
  85
  86         return (PAM_AUTH_ERR);
  87 }
  88
  89 PAM_EXTERN int
  90 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
  91     int argc __unused, const char *argv[] __unused)
  92 {
  93
  94         return (PAM_SUCCESS);
  95 }
  96
  97 PAM_MODULE_ENTRY("pam_self");