NAME

ugidfw — firewall-like access controls for file system objects

SYNOPSIS

ugidfw

add subject [ not][ [ !] uid uid | minuid:maxuid][ [ !] gid gid | mingid:maxgid][ [ !] jailid jailid] object [ not][ [ !] uid uid | minuid:maxuid][ [ !] gid gid | mingid:maxgid][ [ !] filesys path][ [ !] suid][ [ !] sgid][ [ !] uid_of_subject][ [ !] gid_of_subject][ [ !] type ardbclsp] mode arswxn

ugidfw

list

ugidfw

set rulenum subject [ not][ [ !] uid uid | minuid:maxuid][ [ !] gid gid | mingid:maxgid][ [ !] jailid jailid] object [ not][ [ !] uid uid | minuid:maxuid][ [ !] gid gid | mingid:maxgid][ [ !] filesys path][ [ !] suid][ [ !] sgid][ [ !] uid_of_subject][ [ !] gid_of_subject][ [ !] type ardbclsp] mode arswxn

ugidfw

remove rulenum

DESCRIPTION

The ugidfw utility provides an ipfw(8)-like interface to manage access to file system objects by UID and GID, supported by the mac_bsdextended(4) mac(9) policy.

The arguments are as follows:

add subject ... object ... mode arswxn

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 ugidfw rules in the system.

set rulenum subject ... object ... mode arswxn

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.

subject [ not][ [ !] uid uid | minuid:maxuid][ [ !] gid gid | mingid:maxgid][ [ !] jailid jailid]

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, separated by a colon. The subject can be required to be in a particular jail with the jailid.

object [ not][ [ !] uid uid | minuid:maxuid][ [ !] gid gid | mingid:maxgid][ [ !] filesys path][ [ !] suid][ [ !] sgid][ [ !] uid_of_subject][ [ !] gid_of_subject][ [ !] type ardbclsp]

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, separated by a colon. The object can be required to be in a particular filesystem by specifying 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.

SEE ALSO

mac_bsdextended(4), mac(9)

HISTORY

The ugidfw utility first appeared in FreeBSD 5.0.

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.