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: releng/5.4/sys/security/mac_ifoff/mac_ifoff.c 126097 2004-02-22 00:33:12Z 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/mac.h>
49 #include <sys/mount.h>
50 #include <sys/proc.h>
51 #include <sys/systm.h>
52 #include <sys/sysproto.h>
53 #include <sys/sysent.h>
54 #include <sys/vnode.h>
55 #include <sys/file.h>
56 #include <sys/socket.h>
57 #include <sys/socketvar.h>
58 #include <sys/sysctl.h>
59
60 #include <net/bpfdesc.h>
61 #include <net/if.h>
62 #include <net/if_types.h>
63 #include <net/if_var.h>
64
65 #include <vm/vm.h>
66
67 #include <sys/mac_policy.h>
68
69 SYSCTL_DECL(_security_mac);
70
71 SYSCTL_NODE(_security_mac, OID_AUTO, ifoff, CTLFLAG_RW, 0,
72 "TrustedBSD mac_ifoff policy controls");
73
74 static int mac_ifoff_enabled = 1;
75 SYSCTL_INT(_security_mac_ifoff, OID_AUTO, enabled, CTLFLAG_RW,
76 &mac_ifoff_enabled, 0, "Enforce ifoff policy");
77 TUNABLE_INT("security.mac.ifoff.enabled", &mac_ifoff_enabled);
78
79 static int mac_ifoff_lo_enabled = 1;
80 SYSCTL_INT(_security_mac_ifoff, OID_AUTO, lo_enabled, CTLFLAG_RW,
81 &mac_ifoff_lo_enabled, 0, "Enable loopback interfaces");
82 TUNABLE_INT("security.mac.ifoff.lo_enabled", &mac_ifoff_lo_enabled);
83
84 static int mac_ifoff_other_enabled = 0;
85 SYSCTL_INT(_security_mac_ifoff, OID_AUTO, other_enabled, CTLFLAG_RW,
86 &mac_ifoff_other_enabled, 0, "Enable other interfaces");
87 TUNABLE_INT("security.mac.ifoff.other_enabled", &mac_ifoff_other_enabled);
88
89 static int mac_ifoff_bpfrecv_enabled = 0;
90 SYSCTL_INT(_security_mac_ifoff, OID_AUTO, bpfrecv_enabled, CTLFLAG_RW,
91 &mac_ifoff_bpfrecv_enabled, 0, "Enable BPF reception even when interface "
92 "is disabled");
93 TUNABLE_INT("security.mac.ifoff.bpfrecv.enabled", &mac_ifoff_bpfrecv_enabled);
94
95 static int
96 check_ifnet_outgoing(struct ifnet *ifnet)
97 {
98
99 if (!mac_ifoff_enabled)
100 return (0);
101
102 if (mac_ifoff_lo_enabled && ifnet->if_type == IFT_LOOP)
103 return (0);
104
105 if (mac_ifoff_other_enabled && ifnet->if_type != IFT_LOOP)
106 return (0);
107
108 return (EPERM);
109 }
110
111 static int
112 check_ifnet_incoming(struct ifnet *ifnet, int viabpf)
113 {
114 if (!mac_ifoff_enabled)
115 return (0);
116
117 if (mac_ifoff_lo_enabled && ifnet->if_type == IFT_LOOP)
118 return (0);
119
120 if (mac_ifoff_other_enabled && ifnet->if_type != IFT_LOOP)
121 return (0);
122
123 if (viabpf && mac_ifoff_bpfrecv_enabled)
124 return (0);
125
126 return (EPERM);
127 }
128
129 static int
130 mac_ifoff_check_bpfdesc_receive(struct bpf_d *bpf_d, struct label *bpflabel,
131 struct ifnet *ifnet, struct label *ifnetlabel)
132 {
133
134 return (check_ifnet_incoming(ifnet, 1));
135 }
136
137 static int
138 mac_ifoff_check_ifnet_transmit(struct ifnet *ifnet, struct label *ifnetlabel,
139 struct mbuf *m, struct label *mbuflabel)
140 {
141
142 return (check_ifnet_outgoing(ifnet));
143 }
144
145 static int
146 mac_ifoff_check_inpcb_deliver(struct inpcb *inp, struct label *inplabel,
147 struct mbuf *m, struct label *mlabel)
148 {
149
150 M_ASSERTPKTHDR(m);
151 if (m->m_pkthdr.rcvif != NULL)
152 return (check_ifnet_incoming(m->m_pkthdr.rcvif, 0));
153
154 return (0);
155 }
156
157 static int
158 mac_ifoff_check_socket_deliver(struct socket *so, struct label *socketlabel,
159 struct mbuf *m, struct label *mbuflabel)
160 {
161
162 M_ASSERTPKTHDR(m);
163 if (m->m_pkthdr.rcvif != NULL)
164 return (check_ifnet_incoming(m->m_pkthdr.rcvif, 0));
165
166 return (0);
167 }
168
169 static struct mac_policy_ops mac_ifoff_ops =
170 {
171 .mpo_check_bpfdesc_receive = mac_ifoff_check_bpfdesc_receive,
172 .mpo_check_ifnet_transmit = mac_ifoff_check_ifnet_transmit,
173 .mpo_check_inpcb_deliver = mac_ifoff_check_inpcb_deliver,
174 .mpo_check_socket_deliver = mac_ifoff_check_socket_deliver,
175 };
176
177 MAC_POLICY_SET(&mac_ifoff_ops, mac_ifoff, "TrustedBSD MAC/ifoff",
178 MPC_LOADTIME_FLAG_UNLOADOK, NULL);
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