file system firewall policy
To compile the file system firewall policy into your kernel, place the following
lines in your kernel configuration file:
Alternately, to load the file system firewall policy module at boot time, place
the following line in your kernel configuration file:
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
or some other tool utilizing
where they are stored internally and used to determine whether to allow or
deny specific accesses (see
While the traditional
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
works similar to
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.
The 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
- 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
- Currently does nothing interesting.
policy module first
appeared in FreeBSD 5.0
and was developed by the
The "match first case" and logging capabilities were later added by
This software was contributed to the FreeBSD
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.