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