1.\" Copyright (c) 2002 Networks Associates Technology, Inc. 2.\" All rights reserved. 3.\" 4.\" This software was developed for the FreeBSD Project by Chris Costello 5.\" at Safeport Network Services and Network Associates Laboratories, the 6.\" Security Research Division of Network Associates, Inc. under 7.\" DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the 8.\" DARPA CHATS research program. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" $FreeBSD$ 32.\" 33.Dd December 10, 2002 34.Dt MAC_IFOFF 4 35.Os 36.Sh NAME 37.Nm mac_ifoff 38.Nd "interface silencing policy" 39.Sh SYNOPSIS 40To compile the interface silencing policy into your kernel, 41place the following lines in your kernel 42configuration file: 43.Bd -ragged -offset indent 44.Cd "options MAC" 45.Cd "options MAC_IFOFF" 46.Ed 47.Pp 48Alternately, to load the interface silencing policy module at boot time, 49place the following line in your kernel configuration file: 50.Bd -ragged -offset indent 51.Cd "options MAC" 52.Ed 53.Pp 54and in 55.Xr loader.conf 5 : 56.Bd -literal -offset indent 57mac_ifoff_load="YES" 58.Ed 59.Sh DESCRIPTION 60The 61.Nm 62interface silencing module allows administrators to enable and disable 63incoming and outgoing data flow on system network interfaces 64via the 65.Xr sysctl 8 66interface. 67.Pp 68To disable network traffic over the loopback 69.Pq Xr lo 4 70interface, set the 71.Xr sysctl 8 72OID 73.Va security.mac.ifoff.lo_enabled 74to 0 (default 1). 75.Pp 76To enable network traffic over other interfaces, 77set the 78.Xr sysctl 8 79OID 80.Va security.mac.ifoff.other_enabled 81to 1 (default 0). 82.Pp 83To allow BPF traffic to be received, 84even while other traffic is disabled, 85set the 86.Xr sysctl 8 87OID 88.Va security.mac.ifoff.bpfrecv_enabled 89to 1 (default 0). 90.Ss Label Format 91No labels are defined. 92.Sh SEE ALSO 93.Xr mac 4 , 94.Xr mac_bsdextended 4 , 95.Xr mac_lomac 4 , 96.Xr mac_mls 4 , 97.Xr mac_none 4 , 98.Xr mac_partition 4 , 99.Xr mac_portacl 4 , 100.Xr mac_seeotheruids 4 , 101.Xr mac_test 4 , 102.Xr mac 9 103.Sh HISTORY 104The 105.Nm 106policy module first appeared in 107.Fx 5.0 108and was developed by the 109.Tn TrustedBSD 110Project. 111.Sh AUTHORS 112This software was contributed to the 113.Fx 114Project by Network Associates Labs, 115the Security Research Division of Network Associates 116Inc. 117under DARPA/SPAWAR contract N66001-01-C-8035 118.Pq Dq CBOSS , 119as part of the DARPA CHATS research program. 120.Sh BUGS 121See 122.Xr mac 9 123concerning appropriateness for production use. 124The 125.Tn TrustedBSD 126MAC Framework is considered experimental in 127.Fx . 128.Pp 129While the MAC Framework design is intended to support the containment of 130the root user, not all attack channels are currently protected by entry 131point checks. 132As such, MAC Framework policies should not be relied on, in isolation, 133to protect against a malicious privileged user. 134