Copyright (c) 2002 Networks Associates Technology, Inc. All rights reserved. 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. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following...
NAMEmac_bsdextended - file system firewall policy
SYNOPSISTo 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:
and in loader.conf5:
DESCRIPTIONThe sysctl Cm net.inet.tcp.syncookies 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 NOTESWhile 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 sysctl Cm net.inet.tcp.syncookies 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.
SysctlsThe following sysctls may be used to tweak the behavior of :
- Set to zero or one to toggle the policy off or on.
- List the number of defined rules, the maximum rule count is current set at 256.
- List the number of rule slots currently being used.
- Toggle between the old all rules match functionality and the new first rule matches functionality. This is enabled by default.
- Log all access violations via the AUTHPRIV syslog(3) facility.
- Currently does nothing interesting.
SEE ALSOlibugidfw(3), syslog(3), mac(4), mac_biba4, mac_ifoff4, mac_lomac4, mac_mls4, mac_none4, mac_partition4, mac_portacl4, mac_seeotheruids4, mac_test4, ipfw(8), ugidfw(8), mac(9)
HISTORYThe sysctl Cm net.inet.tcp.syncookies policy module first appeared in Fx 5.0 and was developed by the TrustedBSD Project.
The "match first case" and logging capabilities were later added by An Tom Rhodes Aq Mt trhodes@FreeBSD.org .