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 * $FreeBSD$ 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); 179