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mac_bsdextended(4)

NAME

     mac_bsdextended -- file system firewall policy

SYNOPSIS

     To compile the file system firewall policy into your kernel, place the
     following lines in your kernel configuration file:

	   options MAC
	   options MAC_BSDEXTENDED

     Alternately, to load the file system firewall policy module at boot time,
     place the following line in your kernel configuration file:

	   options MAC

     and in loader.conf(5):

	   mac_bsdextended_load="YES"

DESCRIPTION

     The mac_bsdextended interface provides an interface for the system admin-
     istrator to impose mandatory rules regarding users and some system
     objects.  Rules are uploaded to the module (typically using ugidfw(8), or
     some other tool utilizing libugidfw(3)) where they are stored internally
     and used to determine whether to allow or deny specific accesses (see
     ugidfw(8)).

IMPLEMENTATION NOTES

     While the traditional mac(9) entry points are implemented, policy labels
     are not used; instead, access control decisions are made by iterating
     through the internal list of rules until a rule which denies the particu-
     lar access is found, or the end of the list is reached.  The
     mac_bsdextended policy works similar to ipfw(8) or by using a first match
     semantic.	This means that not all rules are applied, only the first
     matched rule; thus if Rule A allows access and Rule B blocks access, Rule
     B will never be applied.

   Sysctls
     The following sysctls may be used to tweak the behavior of
     mac_bsdextended:

     security.mac.bsdextended.enabled
	     Set to zero or one to toggle the policy on or off.

     security.mac.bsdextended.rule_count
	     List the number of defined rules, the maximum rule count is cur-
	     rent set at 256.

     security.mac.bsdextended.rule_slots
	     List the number of rule slots currently being used.

     security.mac.bsdextended.firstmatch_enabled
	     Toggle between the old all rules match functionality and the new
	     first rule matches functionality.	This is enabled by default.

     security.mac.bsdextended.logging
	     Log all access violations via the AUTHPRIV syslog(3) facility.

HISTORY

     The mac_bsdextended policy module first appeared in FreeBSD 5.0 and was
     developed by the TrustedBSD Project.

     The "match first case" and logging capabilities were later added by Tom
     Rhodes <trhodes@FreeBSD.org>.

AUTHORS

     This software was contributed to the FreeBSD Project by NAI Labs, 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.

FreeBSD 5.4		      September 10, 2004		   FreeBSD 5.4

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