bin/setfacl/setfacl.1

.\"-
.\" Copyright (c) 2001 Chris D. Faulhaber
.\" Copyright (c) 2011 Edward Tomasz Napierała
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.Dd April 29, 2023
.Dt SETFACL 1
.Os
.Sh NAME
.Nm setfacl
.Nd set ACL information
.Sh SYNOPSIS
.Nm
.Op Fl R Op Fl H | L | P
.Op Fl bdhkn
.Op Fl a Ar position entries
.Op Fl m Ar entries
.Op Fl M Ar file
.Op Fl x Ar entries | position
.Op Fl X Ar file
.Op Ar
.Sh DESCRIPTION
The
.Nm
utility sets discretionary access control information on
the specified file(s).
If no files are specified, or the list consists of the only
.Sq Fl ,
the file names are taken from the standard input.
.Pp
The following options are available:
.Bl -tag -width indent
.It Fl a Ar position entries
Modify the ACL on the specified files by inserting new
ACL entries
specified in
.Ar entries ,
starting at position
.Ar position ,
counting from zero.
This option is only applicable to NFSv4 ACLs.
.It Fl b
Remove all ACL entries except for the ones synthesized
from the file mode - the three mandatory entries in case
of POSIX.1e ACL.
If the POSIX.1e ACL contains a
.Dq Li mask
entry, the permissions of the
.Dq Li group
entry in the resulting ACL will be set to the permission
associated with both the
.Dq Li group
and
.Dq Li mask
entries of the current ACL.
.It Fl d
The operations apply to the default ACL entries instead of
access ACL entries.
Currently only directories may have
default ACL's.
This option is not applicable to NFSv4 ACLs.
.It Fl h
If the target of the operation is a symbolic link, perform the operation
on the symbolic link itself, rather than following the link.
.It Fl H
If the
.Fl R
option is specified, symbolic links on the command line are followed
and hence unaffected by the command.
(Symbolic links encountered during tree traversal are not followed.)
.It Fl k
Delete any default ACL entries on the specified files.
It
is not considered an error if the specified files do not have
any default ACL entries.
An error will be reported if any of
the specified files cannot have a default entry (i.e.,
non-directories).
This option is not applicable to NFSv4 ACLs.
.It Fl L
If the
.Fl R
option is specified, all symbolic links are followed.
.It Fl m Ar entries
Modify the ACL on the specified file.
New entries will be added, and existing entries will be modified
according to the
.Ar entries
argument.
For NFSv4 ACLs, it is recommended to use the
.Fl a
and
.Fl x
options instead.
.It Fl M Ar file
Modify the ACL entries on the specified files by adding new
ACL entries and modifying existing ACL entries with the ACL
entries specified in the file
.Ar file .
If
.Ar file
is
.Fl ,
the input is taken from stdin.
.It Fl n
Do not recalculate the permissions associated with the ACL
mask entry.
This option is not applicable to NFSv4 ACLs.
.It Fl P
If the
.Fl R
option is specified, no symbolic links are followed.
This is the default.
.It Fl R
Perform the action recursively on any specified directories.
When modifying or adding NFSv4 ACL entries, inheritance flags
are applied only to directories.
.It Fl x Ar entries | position
If
.Ar entries
is specified, remove the ACL entries specified there
from the access or default ACL of the specified files.
Otherwise, remove entry at index
.Ar position ,
counting from zero.
.It Fl X Ar file
Remove the ACL entries specified in the file
.Ar file
from the access or default ACL of the specified files.
.El
.Pp
The above options are evaluated in the order specified
on the command-line.
.Sh POSIX.1e ACL ENTRIES
A POSIX.1E ACL entry contains three colon-separated fields:
an ACL tag, an ACL qualifier, and discretionary access
permissions:
.Bl -tag -width indent
.It Ar "ACL tag"
The ACL tag specifies the ACL entry type and consists of
one of the following:
.Dq Li user
or
.Ql u
specifying the access
granted to the owner of the file or a specified user;
.Dq Li group
or
.Ql g
specifying the access granted to the file owning group
or a specified group;
.Dq Li other
or
.Ql o
specifying the access
granted to any process that does not match any user or group
ACL entry;
.Dq Li mask
or
.Ql m
specifying the maximum access
granted to any ACL entry except the
.Dq Li user
ACL entry for the file owner and the
.Dq Li other
ACL entry.
.It Ar "ACL qualifier"
The ACL qualifier field describes the user or group associated with
the ACL entry.
It may consist of one of the following: uid or
user name, gid or group name, or empty.
For
.Dq Li user
ACL entries, an empty field specifies access granted to the
file owner.
For
.Dq Li group
ACL entries, an empty field specifies access granted to the
file owning group.
.Dq Li mask
and
.Dq Li other
ACL entries do not use this field.
.It Ar "access permissions"
The access permissions field contains up to one of each of
the following:
.Ql r ,
.Ql w ,
and
.Ql x
to set read, write, and
execute permissions, respectively.
Each of these may be excluded
or replaced with a
.Ql -
character to indicate no access.
.El
.Pp
A
.Dq Li mask
ACL entry is required on a file with any ACL entries other than
the default
.Dq Li user ,
.Dq Li group ,
and
.Dq Li other
ACL entries.
If the
.Fl n
option is not specified and no
.Dq Li mask
ACL entry was specified, the
.Nm
utility
will apply a
.Dq Li mask
ACL entry consisting of the union of the permissions associated
with all
.Dq Li group
ACL entries in the resulting ACL.
.Pp
Traditional POSIX interfaces acting on file system object modes have
modified semantics in the presence of POSIX.1e extended ACLs.
When a mask entry is present on the access ACL of an object, the mask
entry is substituted for the group bits; this occurs in programs such
as
.Xr stat 1
or
.Xr ls 1 .
When the mode is modified on an object that has a mask entry, the
changes applied to the group bits will actually be applied to the
mask entry.
These semantics provide for greater application compatibility:
applications modifying the mode instead of the ACL will see
conservative behavior, limiting the effective rights granted by all
of the additional user and group entries; this occurs in programs
such as
.Xr chmod 1 .
.Pp
ACL entries applied from a file using the
.Fl M
or
.Fl X
options shall be of the following form: one ACL entry per line, as
previously specified; whitespace is ignored; any text after a
.Ql #
is ignored (comments).
.Pp
When POSIX.1e ACL entries are evaluated, the access check algorithm checks
the ACL entries in the following order: file owner,
.Dq Li user
ACL entries, file owning group,
.Dq Li group
ACL entries, and
.Dq Li other
ACL entry.
.Pp
Multiple ACL entries specified on the command line are
separated by commas.
.Pp
It is possible for files and directories to inherit ACL entries from their
parent directory.
This is accomplished through the use of the default ACL.
It should be noted that before you can specify a default ACL, the mandatory
ACL entries for user, group, other and mask must be set.
For more details see the examples below.
Default ACLs can be created by using
.Fl d .
.Sh NFSv4 ACL ENTRIES
An NFSv4 ACL entry contains four or five colon-separated fields: an ACL tag,
an ACL qualifier (only for
.Dq Li user
and
.Dq Li group
tags), discretionary access permissions, ACL inheritance flags, and ACL type:
.Bl -tag -width indent
.It Ar "ACL tag"
The ACL tag specifies the ACL entry type and consists of
one of the following:
.Dq Li user
or
.Ql u
specifying the access
granted to the specified user;
.Dq Li group
or
.Ql g
specifying the access granted to the specified group;
.Dq Li owner@
specifying the access granted to the owner of the file;
.Dq Li group@
specifying the access granted to the file owning group;
.Dq Li everyone@
specifying everyone.
Note that
.Dq Li everyone@
is not the same as traditional Unix
.Dq Li other
- it means,
literally, everyone, including file owner and owning group.
.It Ar "ACL qualifier"
The ACL qualifier field describes the user or group associated with
the ACL entry.
It may consist of one of the following: uid or
user name, or gid or group name.
In entries whose tag type is one of
.Dq Li owner@ ,
.Dq Li group@ ,
or
.Dq Li everyone@ ,
this field is omitted altogether, including the trailing colon.
.It Ar "access permissions"
Access permissions may be specified in either short or long form.
Short and long forms may not be mixed.
Permissions in long form are separated by the
.Ql /
character; in short form, they are concatenated together.
Valid permissions are:
.Bl -tag -width ".Dv modify_set"
.It Short
Long
.It r
read_data
.It w
write_data
.It x
execute
.It p
append_data
.It D
delete_child
.It d
delete
.It a
read_attributes
.It A
write_attributes
.It R
read_xattr
.It W
write_xattr
.It c
read_acl
.It C
write_acl
.It o
write_owner
.It s
synchronize
.El
.Pp
In addition, the following permission sets may be used:
.Bl -tag -width ".Dv modify_set"
.It Set
Permissions
.It full_set
all permissions, as shown above
.It modify_set
all permissions except write_acl and write_owner
.It read_set
read_data, read_attributes, read_xattr and read_acl
.It write_set
write_data, append_data, write_attributes and write_xattr
.El
.It Ar "ACL inheritance flags"
Inheritance flags may be specified in either short or long form.
Short and long forms may not be mixed.
Access flags in long form are separated by the
.Ql /
character; in short form, they are concatenated together.
Valid inheritance flags are:
.Bl -tag -width ".Dv short"
.It Short
Long
.It f
file_inherit
.It d
dir_inherit
.It i
inherit_only
.It n
no_propagate
.It I
inherited
.El
.Pp
Other than the "inherited" flag, inheritance flags may be only set on directories.
.It Ar "ACL type"
The ACL type field is either
.Dq Li allow
or
.Dq Li deny .
.El
.Pp
ACL entries applied from a file using the
.Fl M
or
.Fl X
options shall be of the following form: one ACL entry per line, as
previously specified; whitespace is ignored; any text after a
.Ql #
is ignored (comments).
.Pp
NFSv4 ACL entries are evaluated in their visible order.
.Pp
Multiple ACL entries specified on the command line are
separated by commas.
.Pp
Note that the file owner is always granted the read_acl, write_acl,
read_attributes, and write_attributes permissions, even if the ACL
would deny it.
.Sh EXIT STATUS
.Ex -std
.Sh EXAMPLES
.Dl setfacl -d -m u::rwx,g::rx,o::rx,mask::rwx dir
.Dl setfacl -d -m g:admins:rwx dir
.Pp
The first command sets the mandatory elements of the POSIX.1e default ACL.
The second command specifies that users in group admins can have read, write, and execute
permissions for directory named "dir".
It should be noted that any files or directories created underneath "dir" will
inherit these default ACLs upon creation.
.Pp
.Dl setfacl -m u::rwx,g:mail:rw file
.Pp
Sets read, write, and execute permissions for the
.Pa file
owner's POSIX.1e ACL entry and read and write permissions for group mail on
.Pa file .
.Pp
.Dl setfacl -m owner@:rwxp::allow,g:mail:rwp::allow file
.Pp
Semantically equal to the example above, but for NFSv4 ACL.
.Pp
.Dl setfacl -M file1 file2
.Pp
Sets/updates the ACL entries contained in
.Pa file1
on
.Pa file2 .
.Pp
.Dl setfacl -x g:mail:rw file
.Pp
Remove the group mail POSIX.1e ACL entry containing read/write permissions
from
.Pa file .
.Pp
.Dl setfacl -x0 file
.Pp
Remove the first entry from the NFSv4 ACL from
.Pa file .
.Pp
.Dl setfacl -bn file
.Pp
Remove all
.Dq Li access
ACL entries except for the three required from
.Pa file .
.Pp
.Dl getfacl file1 | setfacl -b -n -M - file2
.Pp
Copy ACL entries from
.Pa file1
to
.Pa file2 .
.Sh SEE ALSO
.Xr getfacl 1 ,
.Xr acl 3 ,
.Xr getextattr 8 ,
.Xr setextattr 8 ,
.Xr acl 9 ,
.Xr extattr 9
.Sh STANDARDS
The
.Nm
utility is expected to be
.Tn IEEE
Std 1003.2c compliant.
.Sh HISTORY
Extended Attribute and Access Control List support was developed
as part of the
.Tn TrustedBSD
Project and introduced in
.Fx 5.0 .
NFSv4 ACL support was introduced in
.Fx 8.1 .
.Sh AUTHORS
.An -nosplit
The
.Nm
utility was written by
.An Chris D. Faulhaber Aq Mt jedgar@fxp.org .
NFSv4 ACL support was implemented by
.An Edward Tomasz Napierala Aq Mt trasz@FreeBSD.org .