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
             associated with file descriptors and files.

     mac_set_proc()
             This function, described in mac_set(3), sets the MAC label
             associated with the current process.

     mac_free()
             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 13.1-RELEASE-p6          July 25, 2015         FreeBSD 13.1-RELEASE-p6