.\"-
.\" Copyright (c) 2000 Robert N. M. Watson
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"       $FreeBSD$
.\"
.\" TrustedBSD Project - support for POSIX.1e process capabilities
.\"
.Dd April 1, 2000
.Dt CAP 3
.Os FreeBSD 5.0
.Sh NAME
.Nm cap
.Nd introduction to the POSIX.1e Capability security API
.Sh SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <sys/cap.h>
.Sh DESCRIPTION
The POSIX.1e Capability interface allows processes to manipulate their
capability set, subject to capability manipulation restrictions imposed
by the kernel.  Using the capability API, a process may request a copy
of its capability state, modify the copy of the state, and resubmit the
state for use, if permitted.
.Pp
A variety of functions are provided for manipulating and managing
process capability state and working store state:
.Pp
.Fn cap_init
.Pp
This function is described in
.Xr cap_init 3 ,
and may be used to allocate a fresh capability structure with no capability
flags set.
.Pp
.Fn cap_clear
.Pp
This function is described in
.Xr cap_clear 3 ,
and clears all capability flags in a capability structure.
.Pp
.Fn cap_dup
.Pp
This function is described in
.Xr cap_dup 3 ,
and may be used to duplicate a capability structure.
.Pp
.Fn cap_free
.Pp
This function is described in
.Xr cap_free 3 ,
and may be used to free a capability structure.
.Pp
.Fn cap_get_flag ,
.Fn cap_get_proc
.Pp
These functions, described in
.Xr cap_get_flag 3 ,
and
.Xr cap_get_proc 3 ,
allow retrieval of capability flags from a file, and capability state from
the current process.
.Pp
.Fn cap_set_flag ,
.Fn cap_set_proc
.Pp
These functions, described in
.Xr cap_set_flag 3 ,
and
.Xr cap_set_proc 3 ,
allow setting of the capability flags for a file, and capability state for
the current process.

Documentation of the internal kernel interfaces backing these calls may
be found in
.Xr cap 9 .
The syscalls between the internal interfaces and the public library
routines may change over time, and as such are not documented.  They are
not intended to be called directly without going through the library.
.Sh IMPLEMENTATION NOTES
FreeBSD's support for POSIX.1e interfaces and features is still under
development at this time.
.Sh 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 capabilities,
and labels necessary for mandatory access control.  POSIX.2c describes
a set of userland utilities for manipulating these labels.  These userland
utilities are not bundled with
.Fx 5.0
so as to discourage their
use in the short term.
.\" .Sh FILES
.Sh SEE ALSO
.Xr cap_clear 3 ,
.Xr cap_dup 3 ,
.Xr cap_free 3 ,
.Xr cap_get_flag 3 ,
.Xr cap_get_proc 3 ,
.Xr cap_init 3 ,
.Xr cap_set_flag 3 ,
.Xr cap_set_proc 3 ,
.Xr cap 9
.Sh 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
.Fx 
POSIX.1e implementation
page for more information.
.Sh HISTORY
Support for POSIX.1e Capabilities was developed as part of the TrustedBSD
Project.
POSIX.1e support was introduced in
.Fx 4.0 ,
and development continues.
.Sh AUTHORS
.An Robert N M Watson
.Sh BUGS
These features are not yet included in the base FreeBSD distribution.