xref: /freebsd/sys/security/mac_ntpd/mac_ntpd.c (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2018 Ian Lepore <ian@FreeBSD.org>
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  *
27  * $FreeBSD$
28  */
29 
30 #include <sys/param.h>
31 #include <sys/kernel.h>
32 #include <sys/module.h>
33 #include <sys/priv.h>
34 #include <sys/sysctl.h>
35 #include <sys/ucred.h>
36 
37 #include <security/mac/mac_policy.h>
38 
39 SYSCTL_DECL(_security_mac);
40 
41 static SYSCTL_NODE(_security_mac, OID_AUTO, ntpd,
42     CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
43     "mac_ntpd policy controls");
44 
45 static int ntpd_enabled = 1;
46 SYSCTL_INT(_security_mac_ntpd, OID_AUTO, enabled, CTLFLAG_RWTUN,
47     &ntpd_enabled, 0, "Enable mac_ntpd policy");
48 
49 static int ntpd_uid = 123;
50 SYSCTL_INT(_security_mac_ntpd, OID_AUTO, uid, CTLFLAG_RWTUN,
51     &ntpd_uid, 0, "User id for ntpd user");
52 
53 static int
54 ntpd_priv_grant(struct ucred *cred, int priv)
55 {
56 
57 	if (ntpd_enabled && cred->cr_uid == ntpd_uid) {
58 		switch (priv) {
59 		case PRIV_ADJTIME:
60 		case PRIV_CLOCK_SETTIME:
61 		case PRIV_NTP_ADJTIME:
62 		case PRIV_NETINET_RESERVEDPORT:
63 		case PRIV_NETINET_REUSEPORT:
64 			return (0);
65 		default:
66 			break;
67 		}
68 	}
69 	return (EPERM);
70 }
71 
72 static struct mac_policy_ops ntpd_ops =
73 {
74 	.mpo_priv_grant = ntpd_priv_grant,
75 };
76 
77 MAC_POLICY_SET(&ntpd_ops, mac_ntpd, "MAC/ntpd",
78     MPC_LOADTIME_FLAG_UNLOADOK, NULL);
79