mac_ifoff.c revision 166531 
1/*-
2 * Copyright (c) 1999-2002 Robert N. M. Watson
3 * Copyright (c) 2001-2002 Networks Associates Technology, Inc.
4 * All rights reserved.
5 *
6 * This software was developed by Robert Watson for the TrustedBSD Project.
7 *
8 * This software was developed for the FreeBSD Project in part by Network
9 * Associates Laboratories, the Security Research Division of Network
10 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
11 * as part of the DARPA CHATS research program.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 *    notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 *    notice, this list of conditions and the following disclaimer in the
20 *    documentation and/or other materials provided with the distribution.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * $FreeBSD: head/sys/security/mac_ifoff/mac_ifoff.c 166531 2007-02-06 10:59:23Z rwatson $
35 */
36
37/*
38 * Developed by the TrustedBSD Project.
39 * Limit access to interfaces until they are specifically administratively
40 * enabled.  Prevents protocol stack-driven packet leakage in unsafe
41 * environments.
42 */
43
44#include <sys/types.h>
45#include <sys/param.h>
46#include <sys/conf.h>
47#include <sys/kernel.h>
48#include <sys/mount.h>
49#include <sys/proc.h>
50#include <sys/systm.h>
51#include <sys/sysproto.h>
52#include <sys/sysent.h>
53#include <sys/vnode.h>
54#include <sys/file.h>
55#include <sys/socket.h>
56#include <sys/socketvar.h>
57#include <sys/sysctl.h>
58
59#include <net/bpfdesc.h>
60#include <net/if.h>
61#include <net/if_types.h>
62#include <net/if_var.h>
63
64#include <vm/vm.h>
65
66#include <security/mac/mac_policy.h>
67
68SYSCTL_DECL(_security_mac);
69
70SYSCTL_NODE(_security_mac, OID_AUTO, ifoff, CTLFLAG_RW, 0,
71    "TrustedBSD mac_ifoff policy controls");
72
73static int	mac_ifoff_enabled = 1;
74SYSCTL_INT(_security_mac_ifoff, OID_AUTO, enabled, CTLFLAG_RW,
75    &mac_ifoff_enabled, 0, "Enforce ifoff policy");
76TUNABLE_INT("security.mac.ifoff.enabled", &mac_ifoff_enabled);
77
78static int	mac_ifoff_lo_enabled = 1;
79SYSCTL_INT(_security_mac_ifoff, OID_AUTO, lo_enabled, CTLFLAG_RW,
80    &mac_ifoff_lo_enabled, 0, "Enable loopback interfaces");
81TUNABLE_INT("security.mac.ifoff.lo_enabled", &mac_ifoff_lo_enabled);
82
83static int	mac_ifoff_other_enabled = 0;
84SYSCTL_INT(_security_mac_ifoff, OID_AUTO, other_enabled, CTLFLAG_RW,
85    &mac_ifoff_other_enabled, 0, "Enable other interfaces");
86TUNABLE_INT("security.mac.ifoff.other_enabled", &mac_ifoff_other_enabled);
87
88static int	mac_ifoff_bpfrecv_enabled = 0;
89SYSCTL_INT(_security_mac_ifoff, OID_AUTO, bpfrecv_enabled, CTLFLAG_RW,
90    &mac_ifoff_bpfrecv_enabled, 0, "Enable BPF reception even when interface "
91    "is disabled");
92TUNABLE_INT("security.mac.ifoff.bpfrecv.enabled", &mac_ifoff_bpfrecv_enabled);
93
94static int
95check_ifnet_outgoing(struct ifnet *ifnet)
96{
97
98	if (!mac_ifoff_enabled)
99		return (0);
100
101	if (mac_ifoff_lo_enabled && ifnet->if_type == IFT_LOOP)
102		return (0);
103
104	if (mac_ifoff_other_enabled && ifnet->if_type != IFT_LOOP)
105		return (0);
106
107	return (EPERM);
108}
109
110static int
111check_ifnet_incoming(struct ifnet *ifnet, int viabpf)
112{
113	if (!mac_ifoff_enabled)
114		return (0);
115
116	if (mac_ifoff_lo_enabled && ifnet->if_type == IFT_LOOP)
117		return (0);
118
119	if (mac_ifoff_other_enabled && ifnet->if_type != IFT_LOOP)
120		return (0);
121
122	if (viabpf && mac_ifoff_bpfrecv_enabled)
123		return (0);
124
125	return (EPERM);
126}
127
128static int
129mac_ifoff_check_bpfdesc_receive(struct bpf_d *bpf_d, struct label *bpflabel,
130    struct ifnet *ifnet, struct label *ifnetlabel)
131{
132
133	return (check_ifnet_incoming(ifnet, 1));
134}
135
136static int
137mac_ifoff_check_ifnet_transmit(struct ifnet *ifnet, struct label *ifnetlabel,
138    struct mbuf *m, struct label *mbuflabel)
139{
140
141	return (check_ifnet_outgoing(ifnet));
142}
143
144static int
145mac_ifoff_check_inpcb_deliver(struct inpcb *inp, struct label *inplabel,
146    struct mbuf *m, struct label *mlabel)
147{
148
149	M_ASSERTPKTHDR(m);
150	if (m->m_pkthdr.rcvif != NULL)
151		return (check_ifnet_incoming(m->m_pkthdr.rcvif, 0));
152
153	return (0);
154}
155
156static int
157mac_ifoff_check_socket_deliver(struct socket *so, struct label *socketlabel,
158    struct mbuf *m, struct label *mbuflabel)
159{
160
161	M_ASSERTPKTHDR(m);
162	if (m->m_pkthdr.rcvif != NULL)
163		return (check_ifnet_incoming(m->m_pkthdr.rcvif, 0));
164
165	return (0);
166}
167
168static struct mac_policy_ops mac_ifoff_ops =
169{
170	.mpo_check_bpfdesc_receive = mac_ifoff_check_bpfdesc_receive,
171	.mpo_check_ifnet_transmit = mac_ifoff_check_ifnet_transmit,
172	.mpo_check_inpcb_deliver = mac_ifoff_check_inpcb_deliver,
173	.mpo_check_socket_deliver = mac_ifoff_check_socket_deliver,
174};
175
176MAC_POLICY_SET(&mac_ifoff_ops, mac_ifoff, "TrustedBSD MAC/ifoff",
177    MPC_LOADTIME_FLAG_UNLOADOK, NULL);
178