posix1e(3)

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/capability.h>
#include <sys/mac.h>

DESCRIPTION

The IEEE POSIX.1e specification never left draft form, but

the interfaces
it describes are now widely used despite inherent limita

tions. Currently, only a few of the interfaces and features are imple

mented in
FreeBSD, although efforts are underway to complete the inte

gration at
this time.

POSIX.1e describes five security extensions to the base

POSIX.1 API:
Access Control Lists (ACLs), Auditing, Capabilities, Manda

tory Access
Control, and Information Flow Labels. FreeBSD supports

POSIX.1e ACL
interfaces, as well as POSIX.1e-like MAC interfaces. The

TrustedBSD Project has produced but not integrated an implementation of

POSIX.1e Capabilities.

POSIX.1e defines both syntax and semantics for these fea

tures, but fairly
substantial changes are required to implement these features

in the operating system.

As shipped, FreeBSD 4.0 provides API and VFS support for

ACLs, but not an
implementation on any native file system. FreeBSD 5.0 in

cludes support
for ACLs as part of UFS1 and UFS2, as well as necessary VFS

support for
additional file systems to export ACLs as appropriate.

Available API
calls relating to ACLs are described in detail in acl(3).

As shipped, FreeBSD 5.0 includes support for Mandatory Ac

cess Control as
well as POSIX.1e-like APIs for label management. More in

formation on API
calls relating to MAC is available in mac(3).

Additional patches supporting POSIX.1e features are provided

by the
TrustedBSD project:

http://www.TrustedBSD.org/

IMPLEMENTATION NOTES

FreeBSD's support for POSIX.1e interfaces and features is

still under
development at this time, and many of these features are

considered new
or experimental.

ENVIRONMENT

POSIX.1e assigns security labels to all objects, extending

the security
functionality described in POSIX.1. These additional labels

provide
fine-grained discretionary access control, fine-grained ca

pabilities, and
labels necessary for mandatory access control. POSIX.2c de

scribes a set
of userland utilities for manipulating these labels.

Many of these services are supported by extended attributes,

documented
in extattr(2) and extattr(9). While these APIs are not doc

umented in
POSIX.1e, they are similar in structure.

SEE ALSO

extattr(2), acl(3), mac(3), acl(9), extattr(9), mac(9)

STANDARDS

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

of the draft
continues on the cross-platform POSIX.1e implementation

mailing list. To
join this list, see the FreeBSD POSIX.1e implementation page

for more
information.

HISTORY

POSIX.1e support was introduced in FreeBSD 4.0; most of the

features are
available as of FreeBSD 5.0. Development continues.

AUTHORS

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

BUGS

Many of these features are considered new or experimental in

FreeBSD 5.0
and should be deployed with appropriate caution.

BSD January 17, 2000

BSD