1.\"- 2.\" Copyright (c) 2000, 2001, 2002 Robert N. M. Watson 3.\" All rights reserved. 4.\" 5.\" This software was developed by Robert Watson for the TrustedBSD Project. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.Dd September 21, 2023 29.Dt ACL 3 30.Os 31.Sh NAME 32.Nm acl 33.Nd introduction to the POSIX.1e/NFSv4 ACL security API 34.Sh LIBRARY 35.Lb libc 36.Sh SYNOPSIS 37.In sys/types.h 38.In sys/acl.h 39.Sh DESCRIPTION 40.Fx 41permits file systems to export Access Control Lists via the VFS, and 42provides a library for userland access to and manipulation of these ACLs. 43.Fx 44supports POSIX.1e and NFSv4 ACLs, but 45not all file systems provide support for ACLs, and some may require that 46ACL support be explicitly enabled by the administrator. 47The library calls include routines to allocate, duplicate, retrieve, set, 48and 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 ACL semantics alternative to 51POSIX.1e, such as NFSv4. 52Where routines 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; almost 57all of these support routines are implemented in 58.Fx . 59.Pp 60Available functions, sorted by behavior, include: 61.Bl -tag -width indent 62.It Fn acl_add_flag_np 63This function is described in 64.Xr acl_add_flag_np 3 , 65and may be used to add flags to a flagset. 66.It Fn acl_add_perm 67This function is described in 68.Xr acl_add_perm 3 , 69and may be used to add permissions to a permission set. 70.It Fn acl_calc_mask 71This function is described in 72.Xr acl_calc_mask 3 , 73and may be used to calculate and set the permissions associated with 74the 75.Dv ACL_MASK 76entry. 77.It Fn acl_clear_flags_np 78This function is described in 79.Xr acl_clear_flags_np 3 , 80and may be used to clear all flags from a flagset. 81.It Fn acl_clear_perms 82This function is described in 83.Xr acl_clear_perms 3 , 84and may be used to clear all permissions from a permission set. 85.It Fn acl_copy_entry 86This function is described in 87.Xr acl_copy_entry 3 , 88and may be used to copy the contents of an ACL entry. 89.It Xo 90.Fn acl_create_entry , 91.Fn acl_create_entry_np 92.Xc 93These functions are described in 94.Xr acl_create_entry 3 , 95and may be used to create an empty entry in an ACL. 96.It Xo 97.Fn acl_delete_def_file , 98.Fn acl_delete_def_link_np , 99.Fn acl_delete_fd_np , 100.Fn acl_delete_file_np , 101.Fn acl_delete_link_np 102.Xc 103These functions are described in 104.Xr acl_delete 3 , 105and may be used to delete ACLs from file system objects. 106.It Xo 107.Fn acl_delete_entry , 108.Fn acl_delete_entry_np , 109.Xc 110This functions are described in 111.Xr acl_delete_entry 3 , 112and may be used to delete an entry from an ACL. 113.It Fn acl_delete_flag_np 114This function is described in 115.Xr acl_delete_flag_np 3 , 116and may be used to delete flags from a flagset. 117.It Fn acl_delete_perm 118This function is described in 119.Xr acl_delete_perm 3 , 120and may be used to delete permissions from a permset. 121.It Fn acl_dup 122This function is described in 123.Xr acl_dup 3 , 124and may be used to duplicate an ACL structure. 125.It Fn acl_free 126This function is described in 127.Xr acl_free 3 , 128and may be used to free userland working ACL storage. 129.It Fn acl_from_text 130This function is described in 131.Xr acl_from_text 3 , 132and may be used to convert a text-form ACL into working ACL state, if 133the ACL has POSIX.1e or NFSv4 semantics. 134.It Fn acl_get_brand_np 135This function is described in 136.Xr acl_get_brand_np 3 137and may be used to determine whether the ACL has POSIX.1e or NFSv4 semantics. 138.It Fn acl_get_entry 139This function is described in 140.Xr acl_get_entry 3 , 141and may be used to retrieve a designated ACL entry from an ACL. 142.It Xo 143.Fn acl_get_fd , 144.Fn acl_get_fd_np , 145.Fn acl_get_file , 146.Fn acl_get_link_np 147.Xc 148These functions are described in 149.Xr acl_get 3 , 150and may be used to retrieve ACLs from file system objects. 151.It Fn acl_get_entry_type_np 152This function is described in 153.Xr acl_get_entry_type_np 3 , 154and may be used to retrieve an ACL type from an ACL entry. 155.It Fn acl_get_flagset_np 156This function is described in 157.Xr acl_get_flagset_np 3 , 158and may be used to retrieve a flagset from an ACL entry. 159.It Fn acl_get_perm_np 160This function is described in 161.Xr acl_get_perm_np 3 , 162and may be used to check if a permission is set in a permset. 163.It Fn acl_get_permset 164This function is described in 165.Xr acl_get_permset 3 , 166and may be used to retrieve a permset from an ACL entry. 167.It Fn acl_get_qualifier 168This function is described in 169.Xr acl_get_qualifier 3 , 170and may be used to retrieve the qualifier from an ACL entry. 171.It Fn acl_get_tag_type 172This function is described in 173.Xr acl_get_tag_type 3 , 174and may be used to retrieve the tag type from an ACL entry. 175.It Fn acl_init 176This function is described in 177.Xr acl_init 3 , 178and may be used to allocate a fresh (empty) ACL structure. 179.It Fn acl_is_trivial_np 180This function is described in 181.Xr acl_is_trivial_np 3 , 182and may be used to find out whether ACL is trivial. 183.It Xo 184.Fn acl_set_fd , 185.Fn acl_set_fd_np , 186.Fn acl_set_file , 187.Fn acl_set_link_np 188.Xc 189These functions are described in 190.Xr acl_set 3 , 191and may be used to assign an ACL to a file system object. 192.It Fn acl_set_entry_type_np 193This function is described in 194.Xr acl_set_entry_type_np 3 , 195and may be used to set the ACL type of an ACL entry. 196.It Fn acl_set_flagset_np 197This function is described in 198.Xr acl_set_flagset_np 3 , 199and may be used to set the flags of an ACL entry from a flagset. 200.It Fn acl_set_permset 201This function is described in 202.Xr acl_set_permset 3 , 203and may be used to set the permissions of an ACL entry from a permset. 204.It Fn acl_set_qualifier 205This function is described in 206.Xr acl_set_qualifier 3 , 207and may be used to set the qualifier of an ACL. 208.It Fn acl_set_tag_type 209This function is described in 210.Xr acl_set_tag_type 3 , 211and may be used to set the tag type of an ACL. 212.It Fn acl_strip_np 213This function is described in 214.Xr acl_strip_np 3 , 215and may be used to remove extended entries from an ACL. 216.It Xo 217.Fn acl_to_text , 218.Fn acl_to_text_np 219.Xc 220These functions are described in 221.Xr acl_to_text 3 , 222and may be used to generate a text-form of a POSIX.1e or NFSv4 semantics ACL. 223.It Xo 224.Fn acl_valid , 225.Fn acl_valid_fd_np , 226.Fn acl_valid_file_np , 227.Fn acl_valid_link_np 228.Xc 229These functions are described in 230.Xr acl_valid 3 , 231and may be used to validate an ACL as correct POSIX.1e-semantics, or 232as appropriate for a particular file system object regardless of semantics. 233.El 234.Pp 235Documentation of the internal kernel interfaces backing these calls may 236be found in 237.Xr acl 9 . 238The syscalls between the internal interfaces and the public library 239routines may change over time, and as such are not documented. 240They are not intended to be called directly without going through the 241library. 242.Sh SEE ALSO 243.Xr getfacl 1 , 244.Xr setfacl 1 , 245.Xr acl_add_flag_np 3 , 246.Xr acl_add_perm 3 , 247.Xr acl_calc_mask 3 , 248.Xr acl_clear_flags_np 3 , 249.Xr acl_clear_perms 3 , 250.Xr acl_copy_entry 3 , 251.Xr acl_create_entry 3 , 252.Xr acl_delete_entry 3 , 253.Xr acl_delete_flag_np 3 , 254.Xr acl_delete_perm 3 , 255.Xr acl_dup 3 , 256.Xr acl_free 3 , 257.Xr acl_from_text 3 , 258.Xr acl_get 3 , 259.Xr acl_get_brand_np 3 , 260.Xr acl_get_entry_type_np 3 , 261.Xr acl_get_flagset_np 3 , 262.Xr acl_get_perm_np 3 , 263.Xr acl_get_permset 3 , 264.Xr acl_get_qualifier 3 , 265.Xr acl_get_tag_type 3 , 266.Xr acl_init 3 , 267.Xr acl_is_trivial_np 3 , 268.Xr acl_set 3 , 269.Xr acl_set_entry_type_np 3 , 270.Xr acl_set_flagset_np 3 , 271.Xr acl_set_permset 3 , 272.Xr acl_set_qualifier 3 , 273.Xr acl_set_tag_type 3 , 274.Xr acl_strip_np 3 , 275.Xr acl_to_text 3 , 276.Xr acl_valid 3 , 277.Xr posix1e 3 , 278.Xr acl 9 279.Sh STANDARDS 280POSIX.1e assigns security labels to all objects, extending the security 281functionality described in POSIX.1. 282These additional labels provide fine-grained discretionary access control, 283fine-grained capabilities, and labels necessary for mandatory access 284control. 285POSIX.2c describes a set of userland utilities for manipulating these 286labels. 287.Pp 288POSIX.1e is described in IEEE POSIX.1e draft 17. 289.Sh HISTORY 290POSIX.1e support was introduced in 291.Fx 4.0 ; 292.Fx 5.0 293was the first version to include a complete ACL implementation based 294on extended attributes for the UFS and UFS2 file systems. 295NFSv4 ACL support was introduced in 296.Fx 8.0 . 297.Pp 298The 299.Xr getfacl 1 300and 301.Xr setfacl 1 302utilities describe the user tools that permit direct manipulation of complete 303file ACLs. 304.Sh AUTHORS 305.An Robert N M Watson 306