1.\"- 2.\" Copyright (c) 2000 Robert N. M. Watson 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD: src/lib/libposix1e/acl.3,v 1.2.2.5 2001/12/20 16:27:06 ru Exp $ 27.\" $DragonFly: src/lib/libposix1e/acl.3,v 1.3 2004/03/11 12:28:52 hmp Exp $ 28.\" 29.Dd January 28, 2000 30.Dt ACL 3 31.Os 32.Sh NAME 33.Nm acl 34.Nd introduction to the POSIX.1e ACL security API 35.Sh LIBRARY 36.Lb libposix1e 37.Sh SYNOPSIS 38.In sys/types.h 39.In sys/acl.h 40.Sh DESCRIPTION 41As shipped, 42.Dx 43permits file systems to export 44Access Control Lists via the VFS, and provides a library for userland 45access to and manipulation of these ACLs, but support for ACLs is not 46provided by any file systems shipped in the base operating system. 47The library calls shipped with 4.0 include routines to allocate, 48duplicate, retrieve, set, and validate ACLs associated with file objects. 49As well as the POSIX.1e routines, there are a number of non-portable 50extensions defined that allow for alternative ACL semantics than the 51POSIX.1e semantics, such as AFS, NTFS, Coda, and NWFS semantics. Where 52routines are non-standard, they are suffixed with _np to indicate that 53they are not portable. 54.Pp 55POSIX.1e describes a set of ACL manipulation routines to manage the 56contents of ACLs, as well as their relationships with files. This 57manipulation library is not currently implemented in 58.Dx , 59although 60a third party library was under development at the time this document 61was written. There is a general consensus that the POSIX.1e manipulation 62routines are ambiguously defined in the specification, and don't meet the 63needs of most applications. For the time being, applications may 64directly manipulate the ACL structures, defined in acl.h, although the 65recommended usage is to only ever handle text-form ACLs in applications, 66generated and maintained using 67.Fn acl_from_text 68and 69.Fn acl_to_text , 70passed directly to and from the management routines. In this manner, 71an application can remain safely unaware of the contents of ACLs. 72.Pp 73Available functions, sorted by behavior, include: 74.Pp 75.Fn acl_delete_def_file , 76.Fn acl_delete_file_np , 77.Fn acl_delete_fd_np 78.Pp 79These functions are described in 80.Xr acl_delete 3 , 81and may be used to delete ACLs from file system objects. 82.Pp 83.Fn acl_free 84.Pp 85This function is described in 86.Xr acl_free 3 , 87and may be used to free userland working ACL storage. 88.Pp 89.Fn acl_from_text 90.Pp 91This function is described in 92.Xr acl_from_text 3 , 93and may be used to convert a text-form ACL into working ACL state, if 94the ACL has POSIX.1e semantics. 95.Pp 96.Fn acl_get_file , 97.Fn acl_get_fd , 98.Fn acl_get_fd_np 99.Pp 100These functions are described in 101.Xr acl_get 3 , 102and may be used to retrieve ACLs from file system objects. 103.Pp 104.Fn acl_init 105.Pp 106This function is described in 107.Xr acl_init 3 , 108and may be used to allocate a fresh (empty) ACL structure. 109.Pp 110.Fn acl_dup 111.Pp 112This function is described in 113.Xr acl_dup 3 , 114and may be used to duplicate an ACL structure. 115.Pp 116.Fn acl_set_file , 117.Fn acl_set_fd , 118.Fn acl_set_fd_np 119.Pp 120These functions are described in 121.Xr acl_set 3 , 122and may be used to assign an ACL to a file system object. 123.Pp 124.Fn acl_to_text 125.Pp 126This function is described in 127.Xr acl_to_text 3 , 128and may be used to generate a text-form of a POSIX.1e semantics ACL. 129.Pp 130.Fn acl_valid , 131.Fn acl_valid_file_np , 132.Fn acl_valid_fd_np 133.Pp 134Thee functions are described in 135.Xr acl_valid 3 , 136and may be used to validate an ACL as correct POSIX.1e-semantics, or 137as appropriate for a particular file system object regardless of semantics. 138.Pp 139Documentation of the internal kernel interfaces backing these calls may 140be found in 141.Xr acl 9 . 142The syscalls between the internal interfaces and the public library 143routines may change over time, and as such are not documented. They are 144not intended to be called directly without going through the library. 145.Sh IMPLEMENTATION NOTES 146.Dx Ns 's 147support for POSIX.1e interfaces and features is still under 148development at this time. 149.Sh ENVIRONMENT 150POSIX.1e assigns security labels to all objects, extending the security 151functionality described in POSIX.1. These additional labels provide 152fine-grained discretionary access control, fine-grained capabilities, 153and labels necessary for mandatory access control. POSIX.2c describes 154a set of userland utilities for manipulating these labels. These userland 155utilities are not bundled with 156.Dx 157so as to discourage their 158use in the short term. 159.\" .Sh FILES 160.Sh SEE ALSO 161.Xr acl 3 , 162.Xr acl_dup 3 , 163.Xr acl_free 3 , 164.Xr acl_from_text 3 , 165.Xr acl_get 3 , 166.Xr acl_set 3 , 167.Xr acl_to_text 3 , 168.Xr acl_valid 3 , 169.Xr acl 9 170.Sh STANDARDS 171POSIX.1e is described in IEEE POSIX.1e draft 17. Discussion 172of the draft continues on the cross-platform POSIX.1e implementation 173mailing list. To join this list, see the 174.Fx 175POSIX.1e implementation 176page for more information. 177.Sh HISTORY 178POSIX.1e support was introduced in 179.Fx 4.0 , 180and development continues. 181.Sh AUTHORS 182.An Robert N M Watson 183.Sh BUGS 184These features are not yet fully implemented. In particular, the shipped 185version of UFS/FFS does not support storage of additional security labels, 186and so is unable to (easily) provide support for most of these features. 187