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.\" $FreeBSD$ 27.\" 28.Dd January 28, 2000 29.Dt ACL 3 30.Os FreeBSD 4.0 31.Sh NAME 32.Nm acl 33.Nd introduction to the POSIX.1e ACL security API 34.Sh SYNOPSIS 35.Fd #include <sys/types.h> 36.Fd #include <sys/acl.h> 37.Sh DESCRIPTION 38As shipped, 39.Fx 4.0 40permits file systems to export 41Access Control Lists via the VFS, and provides a library for userland 42access to and manipulation of these ACLs, but support for ACLs is not 43provided by any file systems shipped in the base operating system. 44The library calls shipped with 4.0 include routines to allocate, 45duplicate, retrieve, set, and validate ACLs associated with file objects. 46As well as the POSIX.1e routines, there are a number of non-portable 47extensions defined that allow for alternative ACL semantics than the 48POSIX.1e semantics, such as AFS, NTFS, Coda, and NWFS semantics. Where 49routines are non-standard, they are suffixed with _np to indicate that 50they are not portable. 51 52POSIX.1e describes a set of ACL manipulation routines to manage the 53contents of ACLs, as well as their relationships with files. This 54manipulation library is not currently implemented in FreeBSD, although 55a third party library was under development at the time this document 56was written. There is a general consensus that the POSIX.1e manipulation 57routines are ambiguously defined in the specification, and don't meet the 58needs of most applications. For the time being, applications may 59directly manipulate the ACL structures, defined in acl.h, although the 60recommended usage is to only ever handle text-form ACLs in applications, 61generated and maintained using 62.Fn acl_from_text 63and 64.Fn acl_to_text , 65passed directly to and from the management routines. In this manner, 66an application can remain safely unaware of the contents of ACLs. 67 68Available functions, sorted by behavior, include: 69 70.Fn acl_delete_def_file , 71.Fn acl_delete_file_np , 72.Fn acl_delete_fd_np 73 74These functions are described in 75.Xr acl_delete 3 , 76and may be used to delete ACLs from file system objects. 77 78.Fn acl_free 79 80This function is described in 81.Xr acl_free 3 , 82and may be used to free userland working ACL storage. 83 84.Fn acl_from_text 85 86This function is described in 87.Xr acl_from_text 3 , 88and may be used to convert a text-form ACL into working ACL state, if 89the ACL has POSIX.1e semantics. 90 91.Fn acl_get_file , 92.Fn acl_get_fd , 93.Fn acl_get_fd_np 94 95These functions are described in 96.Xr acl_get 3 , 97and may be used to retrieve ACLs from file system objects. 98 99.Fn acl_init 100 101This function is described in 102.Xr acl_init 3 , 103and may be used to allocate a fresh (empty) ACL structure. 104 105.Fn acl_dup 106 107This function is described in 108.Xr acl_dup 3 , 109and may be used to duplicate an ACL structure. 110 111.Fn acl_set_file , 112.Fn acl_set_fd , 113.Fn acl_set_fd_np 114 115These functions are described in 116.Xr acl_set 3 , 117and may be used to assign an ACL to a file system object. 118 119.Fn acl_to_text 120 121This function is described in 122.Xr acl_to_text 3 , 123and may be used to generate a text-form of a POSIX.1e semantics ACL. 124 125.Fn acl_valid , 126.Fn acl_valid_file_np , 127.Fn acl_valid_fd_np 128 129Thee functions are described in 130.Xr acl_valid 3 , 131and may be used to validate an ACL as correct POSIX.1e-semantics, or 132as appropriate for a particular file system object regardless of semantics. 133 134Documentation of the internal kernel interfaces backing these calls may 135be found in 136.Xr acl 9 . 137The syscalls between the internal interfaces and the public library 138routines may change over time, and as such are not documented. They are 139not intended to be called directly without going through the library. 140.Sh IMPLEMENTATION NOTES 141FreeBSD's support for POSIX.1e interfaces and features is still under 142development at this time. 143.Sh ENVIRONMENT 144POSIX.1e assigns security labels to all objects, extending the security 145functionality described in POSIX.1. These additional labels provide 146fine-grained discretionary access control, fine-grained capabilities, 147and labels necessary for mandatory access control. POSIX.2c describes 148a set of userland utilities for manipulating these labels. These userland 149utilities are not bundled with 150.Fx 4.0 151so as to discourage their 152use in the short term. 153.\" .Sh FILES 154.Sh SEE ALSO 155.Xr acl 3 , 156.Xr acl_dup 3 , 157.Xr acl_free 3 , 158.Xr acl_from_text 3 , 159.Xr acl_get 3 , 160.Xr acl_set 3 , 161.Xr acl_to_text 3 , 162.Xr acl_valid 3 , 163.Xr acl 9 164.Sh STANDARDS 165POSIX.1e is described in IEEE POSIX.1e draft 17. Discussion 166of the draft continues on the cross-platform POSIX.1e implementation 167mailing list. To join this list, see the 168.Fx 169POSIX.1e implementation 170page for more information. 171.Sh HISTORY 172POSIX.1e support was introduced in 173.Fx 4.0 , 174and development continues. 175.Sh AUTHORS 176.An Robert N M Watson 177.Sh BUGS 178These features are not yet fully implemented. In particular, the shipped 179version of UFS/FFS does not support storage of additional security labels, 180and so is unable to (easily) provide support for most of these features. 181