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
39 #include <sys/cdefs.h>
40 #define _BSD_SOURCE
41
42 #include <pwd.h>
43 #include <unistd.h>
44 #include <syslog.h>
45
46 #define PAM_SM_AUTH
47
48 #include <security/pam_appl.h>
49 #include <security/pam_modules.h>
50 #include <security/pam_mod_misc.h>
51
52 #define OPT_ALLOW_ROOT "allow_root"
53
54 PAM_EXTERN int
pam_sm_authenticate(pam_handle_t * pamh,int flags __unused,int argc __unused,const char * argv[]__unused)55 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
56 int argc __unused, const char *argv[] __unused)
57 {
58 struct passwd *pwd;
59 const char *luser;
60 int pam_err;
61 uid_t uid;
62
63 pam_err = pam_get_user(pamh, &luser, NULL);
64 if (pam_err != PAM_SUCCESS)
65 return (pam_err);
66 if (luser == NULL || (pwd = getpwnam(luser)) == NULL)
67 return (PAM_AUTH_ERR);
68
69 uid = getuid();
70 if (uid == 0 && !openpam_get_option(pamh, OPT_ALLOW_ROOT))
71 return (PAM_AUTH_ERR);
72
73 if (uid == (uid_t)pwd->pw_uid)
74 return (PAM_SUCCESS);
75
76 PAM_VERBOSE_ERROR("Refused; source and target users differ");
77
78 return (PAM_AUTH_ERR);
79 }
80
81 PAM_EXTERN int
pam_sm_setcred(pam_handle_t * pamh __unused,int flags __unused,int argc __unused,const char * argv[]__unused)82 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
83 int argc __unused, const char *argv[] __unused)
84 {
85
86 return (PAM_SUCCESS);
87 }
88
89 PAM_MODULE_ENTRY("pam_self");
90