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 39 /* 40 * Developed by the TrustedBSD Project. 41 * 42 * Limit access to interfaces until they are specifically administratively 43 * enabled. Prevents protocol stack-driven packet leakage in unsafe 44 * environments. 45 */ 46 47 #include <sys/param.h> 48 #include <sys/kernel.h> 49 #include <sys/module.h> 50 #include <sys/mbuf.h> 51 #include <sys/socket.h> 52 #include <sys/sysctl.h> 53 54 #include <net/if.h> 55 #include <net/if_var.h> 56 #include <net/if_types.h> 57 #include <net/bpfdesc.h> 58 59 #include <security/mac/mac_policy.h> 60 61 static SYSCTL_NODE(_security_mac, OID_AUTO, ifoff, 62 CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 63 "TrustedBSD mac_ifoff policy controls"); 64 65 static int ifoff_enabled = 1; 66 SYSCTL_INT(_security_mac_ifoff, OID_AUTO, enabled, CTLFLAG_RWTUN, 67 &ifoff_enabled, 0, "Enforce ifoff policy"); 68 69 static int ifoff_lo_enabled = 1; 70 SYSCTL_INT(_security_mac_ifoff, OID_AUTO, lo_enabled, CTLFLAG_RWTUN, 71 &ifoff_lo_enabled, 0, "Enable loopback interfaces"); 72 73 static int ifoff_other_enabled = 0; 74 SYSCTL_INT(_security_mac_ifoff, OID_AUTO, other_enabled, CTLFLAG_RWTUN, 75 &ifoff_other_enabled, 0, "Enable other interfaces"); 76 77 static int ifoff_bpfrecv_enabled = 0; 78 SYSCTL_INT(_security_mac_ifoff, OID_AUTO, bpfrecv_enabled, CTLFLAG_RWTUN, 79 &ifoff_bpfrecv_enabled, 0, "Enable BPF reception even when interface " 80 "is disabled"); 81 82 static int 83 ifnet_check_outgoing(struct ifnet *ifp) 84 { 85 86 if (!ifoff_enabled) 87 return (0); 88 89 if (ifoff_lo_enabled && if_gettype(ifp) == IFT_LOOP) 90 return (0); 91 92 if (ifoff_other_enabled && if_gettype(ifp) != IFT_LOOP) 93 return (0); 94 95 return (EPERM); 96 } 97 98 static int 99 ifnet_check_incoming(struct ifnet *ifp, int viabpf) 100 { 101 if (!ifoff_enabled) 102 return (0); 103 104 if (ifoff_lo_enabled && if_gettype(ifp) == IFT_LOOP) 105 return (0); 106 107 if (ifoff_other_enabled && if_gettype(ifp) != IFT_LOOP) 108 return (0); 109 110 if (viabpf && ifoff_bpfrecv_enabled) 111 return (0); 112 113 return (EPERM); 114 } 115 116 /* 117 * Object-specific entry point implementations are sorted alphabetically by 118 * object type and then by operation. 119 */ 120 static int 121 ifoff_bpfdesc_check_receive(struct bpf_d *d, struct label *dlabel, 122 struct ifnet *ifp, struct label *ifplabel) 123 { 124 125 return (ifnet_check_incoming(ifp, 1)); 126 } 127 128 static int 129 ifoff_ifnet_check_transmit(struct ifnet *ifp, struct label *ifplabel, 130 struct mbuf *m, struct label *mlabel) 131 { 132 133 return (ifnet_check_outgoing(ifp)); 134 } 135 136 static int 137 ifoff_inpcb_check_deliver(struct inpcb *inp, struct label *inplabel, 138 struct mbuf *m, struct label *mlabel) 139 { 140 141 M_ASSERTPKTHDR(m); 142 if (m->m_pkthdr.rcvif != NULL) 143 return (ifnet_check_incoming(m->m_pkthdr.rcvif, 0)); 144 145 return (0); 146 } 147 148 static int 149 ifoff_socket_check_deliver(struct socket *so, struct label *solabel, 150 struct mbuf *m, struct label *mlabel) 151 { 152 153 M_ASSERTPKTHDR(m); 154 if (m->m_pkthdr.rcvif != NULL) 155 return (ifnet_check_incoming(m->m_pkthdr.rcvif, 0)); 156 157 return (0); 158 } 159 160 static struct mac_policy_ops ifoff_ops = 161 { 162 .mpo_bpfdesc_check_receive = ifoff_bpfdesc_check_receive, 163 .mpo_ifnet_check_transmit = ifoff_ifnet_check_transmit, 164 .mpo_inpcb_check_deliver = ifoff_inpcb_check_deliver, 165 .mpo_socket_check_deliver = ifoff_socket_check_deliver, 166 }; 167 168 MAC_POLICY_SET(&ifoff_ops, mac_ifoff, "TrustedBSD MAC/ifoff", 169 MPC_LOADTIME_FLAG_UNLOADOK, NULL); 170