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