xref: /freebsd/lib/libpam/modules/pam_securetty/pam_securetty.c (revision 22cf89c938886d14f5796fc49f9f020c23ea8eaf)
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 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 #include <sys/types.h>
41 #include <sys/stat.h>
42 #include <pwd.h>
43 #include <ttyent.h>
44 #include <string.h>
45 
46 #define PAM_SM_ACCOUNT
47 
48 #include <security/pam_appl.h>
49 #include <security/pam_modules.h>
50 #include <security/pam_mod_misc.h>
51 
52 #define TTY_PREFIX	"/dev/"
53 
54 PAM_EXTERN int
55 pam_sm_acct_mgmt(pam_handle_t *pamh __unused, int flags __unused,
56     int argc __unused, const char *argv[] __unused)
57 {
58 	struct passwd *pwd;
59 	struct ttyent *ty;
60 	const char *user;
61 	const void *tty;
62 	int pam_err;
63 
64 	pam_err = pam_get_user(pamh, &user, NULL);
65 	if (pam_err != PAM_SUCCESS)
66 		return (pam_err);
67 	if (user == NULL || (pwd = getpwnam(user)) == NULL)
68 		return (PAM_SERVICE_ERR);
69 
70 	PAM_LOG("Got user: %s", user);
71 
72 	/* If the user is not root, secure ttys do not apply */
73 	if (pwd->pw_uid != 0)
74 		return (PAM_SUCCESS);
75 
76 	pam_err = pam_get_item(pamh, PAM_TTY, &tty);
77 	if (pam_err != PAM_SUCCESS)
78 		return (pam_err);
79 
80 	PAM_LOG("Got TTY: %s", (const char *)tty);
81 
82 	/* Ignore any "/dev/" on the PAM_TTY item */
83 	if (tty != NULL && strncmp(TTY_PREFIX, tty, sizeof(TTY_PREFIX)) == 0) {
84 		PAM_LOG("WARNING: PAM_TTY starts with " TTY_PREFIX);
85 		tty = (const char *)tty + sizeof(TTY_PREFIX) - 1;
86 	}
87 
88 	if (tty != NULL && (ty = getttynam(tty)) != NULL &&
89 	    (ty->ty_status & TTY_SECURE) != 0)
90 		return (PAM_SUCCESS);
91 
92 	PAM_VERBOSE_ERROR("Not on secure TTY");
93 	return (PAM_AUTH_ERR);
94 }
95 
96 PAM_MODULE_ENTRY("pam_securetty");
97