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 * $FreeBSD$
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/mbuf.h>
53#include <sys/socket.h>
54#include <sys/sysctl.h>
55
56#include <net/if.h>
57#include <net/if_var.h>
58#include <net/if_types.h>
59#include <net/bpfdesc.h>
60
61#include <security/mac/mac_policy.h>
62
63SYSCTL_DECL(_security_mac);
64
65static SYSCTL_NODE(_security_mac, OID_AUTO, ifoff, CTLFLAG_RW, 0,
66    "TrustedBSD mac_ifoff policy controls");
67
68static int	ifoff_enabled = 1;
69SYSCTL_INT(_security_mac_ifoff, OID_AUTO, enabled, CTLFLAG_RWTUN,
70    &ifoff_enabled, 0, "Enforce ifoff policy");
71
72static int	ifoff_lo_enabled = 1;
73SYSCTL_INT(_security_mac_ifoff, OID_AUTO, lo_enabled, CTLFLAG_RWTUN,
74    &ifoff_lo_enabled, 0, "Enable loopback interfaces");
75
76static int	ifoff_other_enabled = 0;
77SYSCTL_INT(_security_mac_ifoff, OID_AUTO, other_enabled, CTLFLAG_RWTUN,
78    &ifoff_other_enabled, 0, "Enable other interfaces");
79
80static int	ifoff_bpfrecv_enabled = 0;
81SYSCTL_INT(_security_mac_ifoff, OID_AUTO, bpfrecv_enabled, CTLFLAG_RWTUN,
82    &ifoff_bpfrecv_enabled, 0, "Enable BPF reception even when interface "
83    "is disabled");
84
85static int
86ifnet_check_outgoing(struct ifnet *ifp)
87{
88
89	if (!ifoff_enabled)
90		return (0);
91
92	if (ifoff_lo_enabled && ifp->if_type == IFT_LOOP)
93		return (0);
94
95	if (ifoff_other_enabled && ifp->if_type != IFT_LOOP)
96		return (0);
97
98	return (EPERM);
99}
100
101static int
102ifnet_check_incoming(struct ifnet *ifp, int viabpf)
103{
104	if (!ifoff_enabled)
105		return (0);
106
107	if (ifoff_lo_enabled && ifp->if_type == IFT_LOOP)
108		return (0);
109
110	if (ifoff_other_enabled && ifp->if_type != IFT_LOOP)
111		return (0);
112
113	if (viabpf && ifoff_bpfrecv_enabled)
114		return (0);
115
116	return (EPERM);
117}
118
119/*
120 * Object-specific entry point implementations are sorted alphabetically by
121 * object type and then by operation.
122 */
123static int
124ifoff_bpfdesc_check_receive(struct bpf_d *d, struct label *dlabel,
125    struct ifnet *ifp, struct label *ifplabel)
126{
127
128	return (ifnet_check_incoming(ifp, 1));
129}
130
131static int
132ifoff_ifnet_check_transmit(struct ifnet *ifp, struct label *ifplabel,
133    struct mbuf *m, struct label *mlabel)
134{
135
136	return (ifnet_check_outgoing(ifp));
137}
138
139static int
140ifoff_inpcb_check_deliver(struct inpcb *inp, struct label *inplabel,
141    struct mbuf *m, struct label *mlabel)
142{
143
144	M_ASSERTPKTHDR(m);
145	if (m->m_pkthdr.rcvif != NULL)
146		return (ifnet_check_incoming(m->m_pkthdr.rcvif, 0));
147
148	return (0);
149}
150
151static int
152ifoff_socket_check_deliver(struct socket *so, struct label *solabel,
153    struct mbuf *m, struct label *mlabel)
154{
155
156	M_ASSERTPKTHDR(m);
157	if (m->m_pkthdr.rcvif != NULL)
158		return (ifnet_check_incoming(m->m_pkthdr.rcvif, 0));
159
160	return (0);
161}
162
163static struct mac_policy_ops ifoff_ops =
164{
165	.mpo_bpfdesc_check_receive = ifoff_bpfdesc_check_receive,
166	.mpo_ifnet_check_transmit = ifoff_ifnet_check_transmit,
167	.mpo_inpcb_check_deliver = ifoff_inpcb_check_deliver,
168	.mpo_socket_check_deliver = ifoff_socket_check_deliver,
169};
170
171MAC_POLICY_SET(&ifoff_ops, mac_ifoff, "TrustedBSD MAC/ifoff",
172    MPC_LOADTIME_FLAG_UNLOADOK, NULL);
173