NAME

posix1e —

introduction to the POSIX.1e security API

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <sys/types.h>
#include <sys/acl.h>
#include <sys/mac.h>

DESCRIPTION

POSIX.1e describes five security extensions to the POSIX.1 API: Access Control Lists (ACLs), Auditing, Capabilities, Mandatory Access Control, and Information Flow Labels. While IEEE POSIX.1e D17 specification has not been standardized, several of its interfaces are widely used.

FreeBSD implements POSIX.1e interface for access control lists, described in acl(3), and supports ACLs on the ffs(7) file system; ACLs must be administratively enabled using tunefs(8).

FreeBSD implements a POSIX.1e-like mandatory access control interface, described in mac(3), although with a number of extensions and important semantic differences.

FreeBSD does not implement the POSIX.1e audit, privilege (capability), or information flow label APIs. However, FreeBSD does implement the libbsm(3) audit API. It also provides capsicum(4), a lightweight OS capability and sandbox framework implementing a hybrid capability system model.

ENVIRONMENT

POSIX.1e assigns security attributes to all objects, extending the security functionality described in POSIX.1. These additional attributes store fine-grained discretionary access control information and mandatory access control labels; for files, they are stored in extended attributes, described in extattr(3).

POSIX.2c describes a set of userland utilities for manipulating these attributes, including getfacl(1) and setfacl(1) for access control lists, and getfmac(8) and setfmac(8) for mandatory access control labels.

STANDARDS

POSIX.1e is described in IEEE POSIX.1e draft 17.

HISTORY

POSIX.1e support was introduced in FreeBSD 4.0; most features were available as of FreeBSD 5.0.

AUTHORS

Robert N M Watson
Chris D. Faulhaber
Thomas Moestl
Ilmar S Habibulin