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MAC(3) FreeBSD Library Functions Manual MAC(3)
NAME
mac - introduction to the MAC security API
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <sys/mac.h>
In the kernel configuration file:
options MAC
DESCRIPTION
Mandatory Access Control labels describe confidentiality, integrity, and
other security attributes of operating system objects, overriding
discretionary access control. Not all system objects support MAC
labeling, and MAC policies must be explicitly enabled by the
administrator. This API, based on POSIX.1e, includes routines to
retrieve, manipulate, set, and convert to and from text the MAC labels on
files and processes.
MAC labels consist of a set of (name, value) tuples, representing
security attributes from MAC policies. For example, this label contains
security labels defined by two policies, mac_biba(4) and mac_mls(4):
biba/low,mls/low
Further syntax and semantics of MAC labels may be found in maclabel(7).
Applications operate on labels stored in mac_t, but can convert between
this internal format and a text format for the purposes of presentation
to uses or external storage. When querying a label on an object, a mac_t
must first be prepared using the interfaces described in mac_prepare(3),
allowing the application to declare which policies it wishes to
interrogate. The application writer can also rely on default label names
declared in mac.conf(5).
When finished with a mac_t, the application must call mac_free(3) to
release its storage.
The following functions are defined:
mac_is_present()
This function, described in mac_is_present(3), allows
applications to test whether MAC is configured, as well as
whether specific policies are configured.
mac_get_fd(), mac_get_file(), mac_get_link(), mac_get_peer()
These functions, described in mac_get(3), retrieve the MAC labels
associated with file descriptors, files, and socket peers.
mac_get_pid(), mac_get_proc()
These functions, described in mac_get(3), retrieve the MAC labels
associated with processes.
mac_set_fd(), mac_set_file(), mac_set_link()
These functions, described in mac_set(3), set the MAC labels
This function, described in mac_free(3), frees working MAC label
storage.
mac_from_text()
This function, described in mac_text(3), converts a text-form MAC
label into working MAC label storage, mac_t.
mac_prepare(), mac_prepare_file_label(), mac_prepare_ifnet_label(),
mac_prepare_process_label(), mac_prepare_type()
These functions, described in mac_prepare(3), allocate working
storage for MAC label operations. mac_prepare(3) prepares a
label based on caller-specified label names; the other calls rely
on the default configuration specified in mac.conf(5).
mac_to_text()
This function is described in mac_text(3), and may be used to
convert a mac_t into a text-form MAC label.
FILES
/etc/mac.conf MAC library configuration file, documented in mac.conf(5).
Provides default behavior for applications aware of MAC
labels on system objects, but without policy-specific
knowledge.
SEE ALSO
mac_free(3), mac_get(3), mac_is_present(3), mac_prepare(3), mac_set(3),
mac_text(3), posix1e(3), mac(4), mac.conf(5), mac(9)
STANDARDS
These APIs are loosely based on the APIs described in POSIX.1e, as
described in IEEE POSIX.1e draft 17. However, the resemblance of these
APIs to the POSIX APIs is loose, as the POSIX APIs were unable to express
some notions required for flexible and extensible access control.
HISTORY
Support for Mandatory Access Control was introduced in FreeBSD 5.0 as
part of the TrustedBSD Project.
FreeBSD 14.0-RELEASE-p11 July 25, 2015 FreeBSD 14.0-RELEASE-p11