.\"- .\" Copyright (c) 2000, 2001 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. .\" .\" $FreeBSD$ .\" .Dd January 28, 2000 .Dt ACL 3 .Os FreeBSD .Sh NAME .Nm acl .Nd introduction to the POSIX.1e ACL security API .Sh LIBRARY .Lb libposix1e .Sh SYNOPSIS .Fd #include .Fd #include .Sh DESCRIPTION .Fx permits file systems to export Access Control Lists via the VFS, and provides a library for userland access to and manipulation of these ACLs. Not all file systems provide support for ACLs, and some may require that ACL support be explicitely enabled by the administrator. The library calls include routines to allocate, duplicate, retrieve, set, and validate ACLs associated with file objects. As well as the POSIX.1e routines, there are a number of non-portable extensions defined that allow for alternative ACL semantics than the POSIX.1e semantics, such as AFS, NTFS, Coda, and NWFS semantics. Where routines are non-standard, they are suffixed with _np to indicate that they are not portable. .Pp POSIX.1e describes a set of ACL manipulation routines to manage the contents of ACLs, as well as their relationships with files; almost all of these support routines are implemented in .Fx . .Pp Available functions, sorted by behavior, include: .Bl -tag -width indent .It Fn acl_add_perm This function is described in .Xr acl_add_perm 3 , and may be used to add permissions to a permission set. .It Fn acl_calc_mask This function is described in .Xr acl_calc_mask 3 , and may be used to calculate and set the permissions associated with the .Dv ACL_MASK entry. .It Fn acl_clear_perms This function is described in .Xr acl_clear_perms 3 , and may be used to clear all permissions from a permission set. .It Fn acl_copy_entry This function is described in .Xr acl_copy_entry 3 , and may be used to copy the contents of an ACL entry. .It Fn acl_create_entry This function is described in .Xr acl_create_entry 3 , and may be used to create an empty entry in an ACL. .It Xo .Fn acl_delete_def_file , .Fn acl_delete_file_np , .Fn acl_delete_fd_np .Xc These functions are described in .Xr acl_delete 3 , and may be used to delete ACLs from file system objects. .It Fn acl_delete_entry This function is described in .Xr acl_delete_entry 3 , and may be used to delete an entry from an ACL. .It Fn acl_delete_perm This function is described in .Xr acl_delete_perm 3 , and may be used to delete permissions from a permset. .It Fn acl_dup This function is described in .Xr acl_dup 3 , and may be used to duplicate an ACL structure. .It Fn acl_free This function is described in .Xr acl_free 3 , and may be used to free userland working ACL storage. .It Fn acl_from_text This function is described in .Xr acl_from_text 3 , and may be used to convert a text-form ACL into working ACL state, if the ACL has POSIX.1e semantics. .It Xo .Fn acl_get_file , .Fn acl_get_fd , .Fn acl_get_fd_np .Xc These functions are described in .Xr acl_get 3 , and may be used to retrieve ACLs from file system objects. .It Fn acl_get_permset This function is described in .Xr acl_get_permset 3 , and may be used to retrieve a permset from an ACL entry. .It Fn acl_get_qualifier This function is described in .Xr acl_get_qualifier 3 , and may be used to retrieve the qualifier from an ACL entry. .It Fn acl_get_tag_type This function is described in .Xr acl_get_tag_type 3 , and may be used to retrieve the tag type from an ACL entry. .It Fn acl_init This function is described in .Xr acl_init 3 , and may be used to allocate a fresh (empty) ACL structure. .It Xo .Fn acl_set_file , .Fn acl_set_fd , .Fn acl_set_fd_np .Xc These functions are described in .Xr acl_set 3 , and may be used to assign an ACL to a file system object. .It Fn acl_set_permset This function is described in .Xr acl_set_permset 3 , and may be used to set the permissions of an ACL entry from a permset. .It Fn acl_set_qualifier This function is described in .Xr acl_set_qualifier 3 , and may be used to set the qualifier of an ACL. .It Fn acl_set_tag_type This function is described in .Xr acl_set_tag_type 3 , and may be used to set the tag type of an ACL. .It Fn acl_to_text This function is described in .Xr acl_to_text 3 , and may be used to generate a text-form of a POSIX.1e semantics ACL. .It Xo .Fn acl_valid , .Fn acl_valid_file_np , .Fn acl_valid_fd_np .Xc These functions are described in .Xr acl_valid 3 , and may be used to validate an ACL as correct POSIX.1e-semantics, or as appropriate for a particular file system object regardless of semantics. .El .Pp Documentation of the internal kernel interfaces backing these calls may be found in .Xr acl 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 .Fx Ns 's support for POSIX.1e interfaces and features is still under development at this time. .Sh SEE ALSO .Xr acl_add_perm 3 , .Xr acl_calc_mask 3 , .Xr acl_clear_perms 3 , .Xr acl_copy_entry 3 , .Xr acl_create_entry 3 , .Xr acl_delete_entry 3 , .Xr acl_delete_perm 3 , .Xr acl_dup 3 , .Xr acl_free 3 , .Xr acl_from_text 3 , .Xr acl_get 3 , .Xr acl_get_permset 3 , .Xr acl_get_qualifier 3 , .Xr acl_get_tag_type 3 , .Xr acl_init 3 , .Xr acl_set 3 , .Xr acl_set_permset 3 , .Xr acl_set_qualifier 3 , .Xr acl_set_tag_type 3 , .Xr acl_to_text 3 , .Xr acl_valid 3 , .Xr acl 9 , .Xr posix1e 3 .Sh STANDARDS 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. .Pp 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 POSIX.1e support was introduced in .Fx 4.0 ; .Fx 5.0 was the first version to include a complete ACL implementation based on extended attributes. .Sh AUTHORS .An Robert N M Watson