securing-filesystems setfacl-en.xml,NONE,1.1
Thomas R. Jones (trjones)
fedora-docs-commits at redhat.com
Wed Jul 20 04:36:18 UTC 2005
Author: trjones
Update of /cvs/docs/securing-filesystems
In directory cvs-int.fedora.redhat.com:/tmp/cvs-serv27405/securing-filesystems
Added Files:
setfacl-en.xml
Log Message:
Setfacl Version 2.2.21
--- NEW FILE setfacl-en.xml ---
<programlisting>
<![CDATA[
NAME
setfacl - set file access control lists
SYNOPSIS
setfacl [-bkndRLPvh] [{-m|-x} acl_spec] [{-M|-X} acl_file] file ...
setfacl --restore=file
DESCRIPTION
This utility sets Access Control Lists (ACLs) of files and directories. On the
command line, a sequence of commands is followed by a sequence of files (which
in turn can be followed by another sequence of commands, ...).
The options -m, and -x expect an ACL on the command line. Multiple ACL entries
are separated by comma characters (`,'). The options -M, and -X read an ACL from
a file or from standard input. The ACL entry format is described in Section ACL
ENTRIES.
The --set and --set-file options set the ACL of a file or a directory. The
previous ACL is replaced. ACL entries for this operation must include permissions.
The -m (--modify) and -M (--modify-file) options modify the ACL of a file or
directory. ACL entries for this operation must include permissions.
The -x (--remove) and -X (--remove-file) options remove ACL enries. Only ACL
entries without the perms field are accepted as parameters, unless POSIXLY_CORRECT
is defined.
When reading from files using the -M, and -X options, setfacl accepts the output
getfacl produces. There is at most one ACL entry per line. After a Pound sign (`#'),
everything up to the end of the line is treated as a comment.
If setfacl is used on a file system which does not support ACLs, setfacl operates
on the file mode permission bits. If the ACL does not fit completely in the
permission bits, setfacl modifies the file mode permission bits to reflect the ACL
as closely as possible, writes an error message to standard error, and returns with
an exit status greater than 0.
PERMISSIONS
The file owner and processes capable of CAP_FOWNER are granted the right to modify
ACLs of a file. This is analogous to the permissions required for accessing the file
mode. (On current Linux systems, root is the only user with the CAP_FOWNER
capability.)
OPTIONS
-b, --remove-all
Remove all extended ACL entries. The base ACL entries of the owner, group and
others are retained.
-k, --remove-default
Remove the Default ACL. If no Default ACL exists, no warnings are issued.
-n, --no-mask
Do not recalculate the effective rights mask. The default behavior of setfacl
is to recalculate the ACL mask entry, unless a mask entry was explicitly given.
The mask entry is set to the union of all permissions of the owning group, and
all named user and group entries. (These are exactly the entries affected by
the mask entry).
--mask
Do recalculate the effective rights mask, even if an ACL mask entry was
explicitly given. (See the -n option.)
-d, --default
All operations apply to the Default ACL. Regular ACL entries in the input set
are promoted to Default ACL entries. Default ACL entries in the input set are
discarded. (A warning is issued if that happens).
--restore=file
Restore a permission backup created by `getfacl -R' or similar. All permissions
of a complete directory subtree are restored using this mechanism. If the input
contains owner comments or group comments, and setfacl is run by root, the owner
and owning group of all files are restored as well. This option cannot be mixed
with other options except `--test'.
--test
Test mode. Instead of changing the ACLs of any files, the resulting ACLs are
listed.
-R, --recursive
Apply operations to all files and directories recursively. This option cannot be
mixed with `--restore'.
-L, --logical
Logical walk, follow symbolic links. The default behavior is to follow symbolic
link arguments, and to skip symbolic links encountered in subdirectories. This
option cannot be mixed with `--restore'.
-P, --physical
Physical walk, skip all symbolic links. This also skips symbolic link arguments.
This option cannot be mixed with `--restore'.
--version
Print the version of setfacl and exit.
--help
Print help explaining the command line options.
--
End of command line options. All remaining parameters are interpreted as file
names, even if they start with a dash.
-
If the file name parameter is a single dash, setfacl reads a list of files
from standard input.
ACL ENTRIES
The setfacl utility recognizes the following ACL entry formats (blanks
inserted for clarity):
[d[efault]:] [u[ser]:]uid [:perms]
Permissions of a named user. Permissions of the file owner if uid is empty.
[d[efault]:] g[roup]:gid [:perms]
Permissions of a named group. Permissions of the owning group if gid is empty.
[d[efault]:] m[ask][:] [:perms]
Effective rights mask
[d[efault]:] o[ther][:] [:perms]
Permissions of others.
Whitespace between delimiter characters and non-delimiter characters is ignored.
Proper ACL entries including permissions are used in modify and set operations.
(options -m, -M, --set and --set-file). Entries without the perms field are used
for deletion of entries (options -x and -X).
For uid and gid you can specify either a name or a number.
The perms field is a combination of characters that indicate the permissions:
read (r), write (w), execute (x), execute only if the file is a directory or
already has execute permission for some user (X). Alternatively, the perms field
can be an octal digit (0-7).
AUTOMATICALLY CREATED ENTRIES
Initially, files and directories contain only the three base ACL entries for
the owner, the group, and others. There are some rules that need to be satisfied
in order for an ACL to be valid:
* The three base entries cannot be removed. There must be exactly one entry of
each of these base entry types.
* Whenever an ACL contains named user entries or named group objects, it must
also contain an effective rights mask.
* Whenever an ACL contains any Default ACL entries, the three Default ACL base
entries (default owner, default group, and default others) must also exist.
* Whenever a Default ACL contains named user entries or named group objects,
it must also contain a default effective rights mask.
To help the user ensure these rules, setfacl creates entries from existing entries
under the following conditions:
* If an ACL contains named user or named group entries, and no mask entry
exists, a mask entry containing the same permissions as the group entry is
created. Unless the -n option is given, the permissions of the mask entry are
further adjusted to include the union of all permissions affected by the mask
entry. (See the -n option description).
* If a Default ACL entry is created, and the Default ACL contains no owner,
owning group, or others entry, a copy of the ACL owner, owning group, or others
entry is added to the Default ACL.
* If a Default ACL contains named user entries or named group entries, and no
mask entry exists, a mask entry containing the same permissions as the default
Default ACL's group entry is added. Unless the -n option is given, the
permissions of the mask entry are further adjusted to inclu de the union of all
permissions affected by the mask entry. (See the -n option description).
EXAMPLES
Granting an additional user read access
setfacl -m u:lisa:r file
Revoking write access from all groups and all named users (using the effective rights
mask)
setfacl -m m::rx file
Removing a named group entry from a file's ACL
setfacl -x g:staff file
Copying the ACL of one file to another
getfacl file1 | setfacl --set-file=- file2
Copying the access ACL into the Default ACL
getfacl --access dir | setfacl -d -M- dir
CONFORMANCE TO POSIX 1003.1e DRAFT STANDARD 17
If the environment variable POSIXLY_CORRECT is defined, the default behavior of
setfacl changes as follows: All non-standard options are disabled. The ``default:''
prefix is disabled. The -x and -X options also accept permission fields (and
ignore them).
AUTHOR
Andreas Gruenbacher, <a.gruenbacher at computer.org>.
Please send your bug reports, suggested features and comments to the above address.
]]>
</programlisting>
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