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 security policy module provides an interface for the system
     administrator 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 particular 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 off or on.

     security.mac.bsdextended.rule_count
             List the number of defined rules, the maximum rule count is current 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.

     security.mac.bsdextended.rules
             Currently does nothing interesting.

SEE ALSO

     libugidfw(3), syslog(3), mac(4), mac_biba(4), mac_ifoff(4), mac_lomac(4), mac_mls(4),
     mac_none(4), mac_partition(4), mac_portacl(4), mac_seeotheruids(4), mac_test(4), ipfw(8),
     ugidfw(8), mac(9)

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.