1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright 2001 Mark R V Murray 5 * All rights reserved. 6 * Copyright (c) 2001 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_nologin/pam_nologin.c 326219 2017-11-26 02:00:33Z pfg $ 39 */ 40 41 #include <sys/types.h> 42 #include <sys/stat.h> 43 #include <fcntl.h> 44 #include <login_cap.h> 45 #include <pwd.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <unistd.h> 49 50 #define PAM_SM_ACCOUNT 51 52 #include <security/pam_appl.h> 53 #include <security/pam_modules.h> 54 #include <security/pam_mod_misc.h> 55 56 #define _PATH_NOLOGIN "/var/run/nologin" 57 58 static char nologin_def[] = _PATH_NOLOGIN; 59 60 PAM_EXTERN int 61 pam_sm_acct_mgmt(pam_handle_t *pamh, int flags, 62 int argc __unused, const char *argv[] __unused) 63 { 64 login_cap_t *lc; 65 struct passwd *pwd; 66 struct stat st; 67 int retval, fd; 68 ssize_t ss; 69 const char *user, *nologin; 70 char *mtmp; 71 72 retval = pam_get_user(pamh, &user, NULL); 73 if (retval != PAM_SUCCESS) 74 return (retval); 75 76 PAM_LOG("Got user: %s", user); 77 78 pwd = getpwnam(user); 79 if (pwd == NULL) 80 return (PAM_USER_UNKNOWN); 81 82 /* 83 * login_getpwclass(3) will select the "root" class by default 84 * if pwd->pw_uid is 0. That class should have "ignorenologin" 85 * capability so that super-user can bypass nologin. 86 */ 87 lc = login_getpwclass(pwd); 88 if (lc == NULL) { 89 PAM_LOG("Unable to get login class for user %s", user); 90 return (PAM_SERVICE_ERR); 91 } 92 93 if (login_getcapbool(lc, "ignorenologin", 0)) { 94 login_close(lc); 95 return (PAM_SUCCESS); 96 } 97 98 nologin = login_getcapstr(lc, "nologin", nologin_def, nologin_def); 99 100 fd = open(nologin, O_RDONLY, 0); 101 if (fd < 0) { 102 login_close(lc); 103 return (PAM_SUCCESS); 104 } 105 106 PAM_LOG("Opened %s file", nologin); 107 108 if (fstat(fd, &st) == 0) { 109 mtmp = malloc(st.st_size + 1); 110 if (mtmp != NULL) { 111 ss = read(fd, mtmp, st.st_size); 112 if (ss > 0) { 113 mtmp[ss] = '\0'; 114 pam_error(pamh, "%s", mtmp); 115 } 116 free(mtmp); 117 } 118 } 119 120 PAM_VERBOSE_ERROR("Administrator refusing you: %s", nologin); 121 122 close(fd); 123 login_close(lc); 124 125 return (PAM_AUTH_ERR); 126 } 127 128 PAM_MODULE_ENTRY("pam_nologin"); 129