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