1/*-
2 * Copyright (c) 1999-2002, 2007 Robert N. M. Watson
3 * Copyright (c) 2001-2002 Networks Associates Technology, Inc.
4 * Copyright (c) 2006 SPARTA, Inc.
5 * All rights reserved.
6 *
7 * This software was developed by Robert Watson for the TrustedBSD Project.
8 *
9 * This software was developed for the FreeBSD Project in part by Network
10 * Associates Laboratories, the Security Research Division of Network
11 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
12 * as part of the DARPA CHATS research program.
13 *
14 * This software was enhanced by SPARTA ISSO under SPAWAR contract
15 * N66001-04-C-6019 ("SEFOS").
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
19 * are met:
20 * 1. Redistributions of source code must retain the above copyright
21 *    notice, this list of conditions and the following disclaimer.
22 * 2. Redistributions in binary form must reproduce the above copyright
23 *    notice, this list of conditions and the following disclaimer in the
24 *    documentation and/or other materials provided with the distribution.
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 * $FreeBSD: releng/10.3/sys/security/mac_ifoff/mac_ifoff.c 227309 2011-11-07 15:43:11Z ed $
39 */
40
41/*
42 * Developed by the TrustedBSD Project.
43 *
44 * Limit access to interfaces until they are specifically administratively
45 * enabled.  Prevents protocol stack-driven packet leakage in unsafe
46 * environments.
47 */
48
49#include <sys/param.h>
50#include <sys/kernel.h>
51#include <sys/module.h>
52#include <sys/socket.h>
53#include <sys/sysctl.h>
54
55#include <net/bpfdesc.h>
56#include <net/if_types.h>
57
58#include <security/mac/mac_policy.h>
59
60SYSCTL_DECL(_security_mac);
61
62static SYSCTL_NODE(_security_mac, OID_AUTO, ifoff, CTLFLAG_RW, 0,
63    "TrustedBSD mac_ifoff policy controls");
64
65static int	ifoff_enabled = 1;
66SYSCTL_INT(_security_mac_ifoff, OID_AUTO, enabled, CTLFLAG_RW,
67    &ifoff_enabled, 0, "Enforce ifoff policy");
68TUNABLE_INT("security.mac.ifoff.enabled", &ifoff_enabled);
69
70static int	ifoff_lo_enabled = 1;
71SYSCTL_INT(_security_mac_ifoff, OID_AUTO, lo_enabled, CTLFLAG_RW,
72    &ifoff_lo_enabled, 0, "Enable loopback interfaces");
73TUNABLE_INT("security.mac.ifoff.lo_enabled", &ifoff_lo_enabled);
74
75static int	ifoff_other_enabled = 0;
76SYSCTL_INT(_security_mac_ifoff, OID_AUTO, other_enabled, CTLFLAG_RW,
77    &ifoff_other_enabled, 0, "Enable other interfaces");
78TUNABLE_INT("security.mac.ifoff.other_enabled", &ifoff_other_enabled);
79
80static int	ifoff_bpfrecv_enabled = 0;
81SYSCTL_INT(_security_mac_ifoff, OID_AUTO, bpfrecv_enabled, CTLFLAG_RW,
82    &ifoff_bpfrecv_enabled, 0, "Enable BPF reception even when interface "
83    "is disabled");
84TUNABLE_INT("security.mac.ifoff.bpfrecv.enabled", &ifoff_bpfrecv_enabled);
85
86static int
87ifnet_check_outgoing(struct ifnet *ifp)
88{
89
90	if (!ifoff_enabled)
91		return (0);
92
93	if (ifoff_lo_enabled && ifp->if_type == IFT_LOOP)
94		return (0);
95
96	if (ifoff_other_enabled && ifp->if_type != IFT_LOOP)
97		return (0);
98
99	return (EPERM);
100}
101
102static int
103ifnet_check_incoming(struct ifnet *ifp, int viabpf)
104{
105	if (!ifoff_enabled)
106		return (0);
107
108	if (ifoff_lo_enabled && ifp->if_type == IFT_LOOP)
109		return (0);
110
111	if (ifoff_other_enabled && ifp->if_type != IFT_LOOP)
112		return (0);
113
114	if (viabpf && ifoff_bpfrecv_enabled)
115		return (0);
116
117	return (EPERM);
118}
119
120/*
121 * Object-specific entry point implementations are sorted alphabetically by
122 * object type and then by operation.
123 */
124static int
125ifoff_bpfdesc_check_receive(struct bpf_d *d, struct label *dlabel,
126    struct ifnet *ifp, struct label *ifplabel)
127{
128
129	return (ifnet_check_incoming(ifp, 1));
130}
131
132static int
133ifoff_ifnet_check_transmit(struct ifnet *ifp, struct label *ifplabel,
134    struct mbuf *m, struct label *mlabel)
135{
136
137	return (ifnet_check_outgoing(ifp));
138}
139
140static int
141ifoff_inpcb_check_deliver(struct inpcb *inp, struct label *inplabel,
142    struct mbuf *m, struct label *mlabel)
143{
144
145	M_ASSERTPKTHDR(m);
146	if (m->m_pkthdr.rcvif != NULL)
147		return (ifnet_check_incoming(m->m_pkthdr.rcvif, 0));
148
149	return (0);
150}
151
152static int
153ifoff_socket_check_deliver(struct socket *so, struct label *solabel,
154    struct mbuf *m, struct label *mlabel)
155{
156
157	M_ASSERTPKTHDR(m);
158	if (m->m_pkthdr.rcvif != NULL)
159		return (ifnet_check_incoming(m->m_pkthdr.rcvif, 0));
160
161	return (0);
162}
163
164static struct mac_policy_ops ifoff_ops =
165{
166	.mpo_bpfdesc_check_receive = ifoff_bpfdesc_check_receive,
167	.mpo_ifnet_check_transmit = ifoff_ifnet_check_transmit,
168	.mpo_inpcb_check_deliver = ifoff_inpcb_check_deliver,
169	.mpo_socket_check_deliver = ifoff_socket_check_deliver,
170};
171
172MAC_POLICY_SET(&ifoff_ops, mac_ifoff, "TrustedBSD MAC/ifoff",
173    MPC_LOADTIME_FLAG_UNLOADOK, NULL);
174