1 /*- 2 * Copyright (c) 1999-2002, 2007 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/param.h> 45 #include <sys/kernel.h> 46 #include <sys/module.h> 47 #include <sys/socket.h> 48 #include <sys/sysctl.h> 49 50 #include <net/bpfdesc.h> 51 #include <net/if_types.h> 52 53 #include <security/mac/mac_policy.h> 54 55 SYSCTL_DECL(_security_mac); 56 57 SYSCTL_NODE(_security_mac, OID_AUTO, ifoff, CTLFLAG_RW, 0, 58 "TrustedBSD mac_ifoff policy controls"); 59 60 static int mac_ifoff_enabled = 1; 61 SYSCTL_INT(_security_mac_ifoff, OID_AUTO, enabled, CTLFLAG_RW, 62 &mac_ifoff_enabled, 0, "Enforce ifoff policy"); 63 TUNABLE_INT("security.mac.ifoff.enabled", &mac_ifoff_enabled); 64 65 static int mac_ifoff_lo_enabled = 1; 66 SYSCTL_INT(_security_mac_ifoff, OID_AUTO, lo_enabled, CTLFLAG_RW, 67 &mac_ifoff_lo_enabled, 0, "Enable loopback interfaces"); 68 TUNABLE_INT("security.mac.ifoff.lo_enabled", &mac_ifoff_lo_enabled); 69 70 static int mac_ifoff_other_enabled = 0; 71 SYSCTL_INT(_security_mac_ifoff, OID_AUTO, other_enabled, CTLFLAG_RW, 72 &mac_ifoff_other_enabled, 0, "Enable other interfaces"); 73 TUNABLE_INT("security.mac.ifoff.other_enabled", &mac_ifoff_other_enabled); 74 75 static int mac_ifoff_bpfrecv_enabled = 0; 76 SYSCTL_INT(_security_mac_ifoff, OID_AUTO, bpfrecv_enabled, CTLFLAG_RW, 77 &mac_ifoff_bpfrecv_enabled, 0, "Enable BPF reception even when interface " 78 "is disabled"); 79 TUNABLE_INT("security.mac.ifoff.bpfrecv.enabled", &mac_ifoff_bpfrecv_enabled); 80 81 static int 82 check_ifnet_outgoing(struct ifnet *ifp) 83 { 84 85 if (!mac_ifoff_enabled) 86 return (0); 87 88 if (mac_ifoff_lo_enabled && ifp->if_type == IFT_LOOP) 89 return (0); 90 91 if (mac_ifoff_other_enabled && ifp->if_type != IFT_LOOP) 92 return (0); 93 94 return (EPERM); 95 } 96 97 static int 98 check_ifnet_incoming(struct ifnet *ifp, int viabpf) 99 { 100 if (!mac_ifoff_enabled) 101 return (0); 102 103 if (mac_ifoff_lo_enabled && ifp->if_type == IFT_LOOP) 104 return (0); 105 106 if (mac_ifoff_other_enabled && ifp->if_type != IFT_LOOP) 107 return (0); 108 109 if (viabpf && mac_ifoff_bpfrecv_enabled) 110 return (0); 111 112 return (EPERM); 113 } 114 115 static int 116 mac_ifoff_check_bpfdesc_receive(struct bpf_d *d, struct label *dlabel, 117 struct ifnet *ifp, struct label *ifplabel) 118 { 119 120 return (check_ifnet_incoming(ifp, 1)); 121 } 122 123 static int 124 mac_ifoff_check_ifnet_transmit(struct ifnet *ifp, struct label *ifplabel, 125 struct mbuf *m, struct label *mlabel) 126 { 127 128 return (check_ifnet_outgoing(ifp)); 129 } 130 131 static int 132 mac_ifoff_check_inpcb_deliver(struct inpcb *inp, struct label *inplabel, 133 struct mbuf *m, struct label *mlabel) 134 { 135 136 M_ASSERTPKTHDR(m); 137 if (m->m_pkthdr.rcvif != NULL) 138 return (check_ifnet_incoming(m->m_pkthdr.rcvif, 0)); 139 140 return (0); 141 } 142 143 static int 144 mac_ifoff_check_socket_deliver(struct socket *so, struct label *solabel, 145 struct mbuf *m, struct label *mlabel) 146 { 147 148 M_ASSERTPKTHDR(m); 149 if (m->m_pkthdr.rcvif != NULL) 150 return (check_ifnet_incoming(m->m_pkthdr.rcvif, 0)); 151 152 return (0); 153 } 154 155 static struct mac_policy_ops mac_ifoff_ops = 156 { 157 .mpo_check_bpfdesc_receive = mac_ifoff_check_bpfdesc_receive, 158 .mpo_check_ifnet_transmit = mac_ifoff_check_ifnet_transmit, 159 .mpo_check_inpcb_deliver = mac_ifoff_check_inpcb_deliver, 160 .mpo_check_socket_deliver = mac_ifoff_check_socket_deliver, 161 }; 162 163 MAC_POLICY_SET(&mac_ifoff_ops, mac_ifoff, "TrustedBSD MAC/ifoff", 164 MPC_LOADTIME_FLAG_UNLOADOK, NULL); 165