1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 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 * $FreeBSD: head/lib/libpam/modules/pam_self/pam_self.c 326219 2017-11-26 02:00:33Z pfg $ 39 */ 40 41 #define _BSD_SOURCE 42 43 #include <pwd.h> 44 #include <unistd.h> 45 #include <syslog.h> 46 47 #define PAM_SM_AUTH 48 49 #include <security/pam_appl.h> 50 #include <security/pam_modules.h> 51 #include <security/pam_mod_misc.h> 52 53 #define OPT_ALLOW_ROOT "allow_root" 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 struct passwd *pwd; 60 const char *luser; 61 int pam_err; 62 uid_t uid; 63 64 pam_err = pam_get_user(pamh, &luser, NULL); 65 if (pam_err != PAM_SUCCESS) 66 return (pam_err); 67 if (luser == NULL || (pwd = getpwnam(luser)) == NULL) 68 return (PAM_AUTH_ERR); 69 70 uid = getuid(); 71 if (uid == 0 && !openpam_get_option(pamh, OPT_ALLOW_ROOT)) 72 return (PAM_AUTH_ERR); 73 74 if (uid == (uid_t)pwd->pw_uid) 75 return (PAM_SUCCESS); 76 77 PAM_VERBOSE_ERROR("Refused; source and target users differ"); 78 79 return (PAM_AUTH_ERR); 80 } 81 82 PAM_EXTERN int 83 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused, 84 int argc __unused, const char *argv[] __unused) 85 { 86 87 return (PAM_SUCCESS); 88 } 89 90 PAM_MODULE_ENTRY("pam_self"); 91