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
56 static char nologin_def[] = _PATH_NOLOGIN;
57
58 PAM_EXTERN int
pam_sm_acct_mgmt(pam_handle_t * pamh,int flags,int argc __unused,const char * argv[]__unused)59 pam_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
126 PAM_MODULE_ENTRY("pam_nologin");
127