The
utility provides an
ipfw(8)Ns-like
interface to manage access to file system objects by UID and GID,
supported by the
mac_bsdextended4
mac(9)
policy.
The arguments are as follows:
addsubject...object...modearswxn
Add a new rule, automatically selecting the rule number.
See the description of
set
for syntax information.
list
Produces a list of all the current
rules in the system.
set rulenumsubject...object...modearswxn
Add a new rule or modify an existing rule.
The arguments are as follows:
rulenum
Rule number.
Entries with a lower rule number
are applied first;
placing the most frequently-matched rules at the beginning of the list
(i.e., lower-numbered)
will yield a slight performance increase.
Subjects performing an operation must match all the conditions given.
A leading
not
means that the subject should not match the remainder of the specification.
A condition may be prefixed by
!
to indicate that particular condition must not match the subject.
The subject can be required to have a particular
uid
and/or
gid
A range of uids/gids can be specified,
seperated by a colon.
The subject can be required to be in a particular jail with the
jailid
The rule will apply only to objects matching all the specified conditions.
A leading
not
means that the object should not match all the remaining conditions.
A condition may be prefixed by
!
to indicate that particular condition must not match the object.
Objects can be required to be owned by the user and/or group specified by
uid
and/or
gid
A range of uids/gids can be specified, seperated by a colon.
The object can be required to be in a particular filesystem by
specifing the filesystem using
filesys
Note,
if the filesystem is unmounted and remounted,
then the rule may need to be reapplied to ensure the correct filesystem
id is used.
The object can be required to have the
suid
or
sgid
bits set.
The owner of the object can be required to match the
uid_of_subject
or the
gid_of_subject
attempting the operation.
The type of the object can be restricted to a subset of
the following types.
a
any file type
r
a regular file
d
a directory
b
a block special device
c
a character special device
l
a symbolic link
s
a unix domain socket
p
a named pipe (FIFO)
mode arswxn
Similar to
chmod(1),
each character represents an access mode.
If the rule applies,
the specified access permissions are enforced
for the object.
When a character is specified in the rule,
the rule will allow for the operation.
Conversely, not including it will cause the operation
to be denied.
The definitions of each character are as follows:
a
administrative operations
r
read access
s
access to file attributes
w
write access
x
execute access
n
none
remove rulenum
Disable and remove the rule with the specified rule number.
This software was contributed to the
Fx 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.
