freebsd-dev/share/man/man4/mac_ifoff.4

.\" Copyright (c) 2002 Networks Associates Technology, Inc.
.\" All rights reserved.
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.\" This software was developed for the FreeBSD Project by Chris Costello
.\" at Safeport Network Services and Network Associates Laboratories, the
.\" Security Research Division of Network Associates, Inc. under
.\" DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
.\" DARPA CHATS research program.
.\"
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.Dd July 25, 2015
.Dt MAC_IFOFF 4
.Os
.Sh NAME
.Nm mac_ifoff
.Nd "interface silencing policy"
.Sh SYNOPSIS
To compile the interface silencing policy into your kernel,
place the following lines in your kernel
configuration file:
.Bd -ragged -offset indent
.Cd "options MAC"
.Cd "options MAC_IFOFF"
.Ed
.Pp
Alternately, to load the interface silencing policy module at boot time,
place the following line in your kernel configuration file:
.Bd -ragged -offset indent
.Cd "options MAC"
.Ed
.Pp
and in
.Xr loader.conf 5 :
.Bd -literal -offset indent
mac_ifoff_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
interface silencing module allows administrators to enable and disable
incoming and outgoing data flow on system network interfaces
via the
.Xr sysctl 8
interface.
.Pp
To disable network traffic over the loopback
.Pq Xr lo 4
interface, set the
.Xr sysctl 8
OID
.Va security.mac.ifoff.lo_enabled
to 0 (default 1).
.Pp
To enable network traffic over other interfaces,
set the
.Xr sysctl 8
OID
.Va security.mac.ifoff.other_enabled
to 1 (default 0).
.Pp
To allow BPF traffic to be received,
even while other traffic is disabled,
set the
.Xr sysctl 8
OID
.Va security.mac.ifoff.bpfrecv_enabled
to 1 (default 0).
.Ss Label Format
No labels are defined.
.Sh SEE ALSO
.Xr mac 4 ,
.Xr mac_bsdextended 4 ,
.Xr mac_lomac 4 ,
.Xr mac_mls 4 ,
.Xr mac_none 4 ,
.Xr mac_partition 4 ,
.Xr mac_portacl 4 ,
.Xr mac_seeotheruids 4 ,
.Xr mac_test 4 ,
.Xr mac 9
.Sh HISTORY
The
.Nm
policy module first appeared in
.Fx 5.0
and was developed by the
.Tn TrustedBSD
Project.
.Sh AUTHORS
This software was contributed to the
.Fx
Project by Network Associates Labs,
the Security Research Division of Network Associates
Inc.
under DARPA/SPAWAR contract N66001-01-C-8035
.Pq Dq CBOSS ,
as part of the DARPA CHATS research program.
.Sh BUGS
While the MAC Framework design is intended to support the containment of
the root user, not all attack channels are currently protected by entry
point checks.
As such, MAC Framework policies should not be relied on, in isolation,
to protect against a malicious privileged user.