Setting ACL Inheritance on ZFS Files in Verbose Format
You can specify whether and how ACLs are inherited on files and directories. By default, ACLs are not propagated. If you set a non-trivial ACL on a directory, the ACL is not inherited by any subsequent directory. You must specify the inheritance of an ACL on a file or directory.
In addition, two ACL properties can be set globally on file systems: aclinherit and aclmode. By default, aclinherit is set to restricted and aclmode is set to groupmask.
For more information, see ACL Inheritance.
Example 8–5 Granting Default ACL Inheritance
By default, ACLs are not propagated through a directory structure.
In the following example, a non-trivial ACE of read_data/write_data/execute is applied for user gozer on the test.dir directory:
# chmod A+user:gozer:read_data/write_data/execute:allow test.dir
# ls -dv test.dir
drwxr-xr-x+ 2 root root 2 May 20 15:41 test.dir
0:user:gozer:list_directory/read_data/add_file/write_data/execute:allow
1:owner@::deny
2:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
3:group@:add_file/write_data/add_subdirectory/append_data:deny
4:group@:list_directory/read_data/execute:allow
5:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
6:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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If a test.dir subdirectory is created, the ACE for user gozer is not propagated. User gozer would only have access to the subdirectory if the permissions on the subdirectory granted him access as the file owner, group member, or everyone@. For example:
# mkdir test.dir/sub.dir
# ls -dv test.dir/sub.dir
drwxr-xr-x 2 root root 2 May 20 15:42 test.dir/sub.dir
0:owner@::deny
1:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
2:group@:add_file/write_data/add_subdirectory/append_data:deny
3:group@:list_directory/read_data/execute:allow
4:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
5:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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Example 8–6 Granting ACL Inheritance on Files and Directories
The following examples identify the file and directory ACEs that are applied when the file_inherit flag is set.
In this example, read_data/write_data permissions are added for files in the test2.dir directory for user gozer so that he has read access on any newly created files:
# chmod A+user:gozer:read_data/write_data:file_inherit:allow test2.dir
# ls -dv test2.dir
drwxr-xr-x+ 2 root root 2 May 20 15:50 test2.dir
0:user:gozer:read_data/write_data:file_inherit:allow
1:owner@::deny
2:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
3:group@:add_file/write_data/add_subdirectory/append_data:deny
4:group@:list_directory/read_data/execute:allow
5:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
6:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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In this example, user gozer's permissions are applied on the newly created test2.dir/file.2 file. The ACL inheritance granted, read_data:file_inherit:allow, means that user gozer can read the contents of any newly created file.
# touch test2.dir/file.2
# ls -v test2.dir/file.2
-rw-r--r--+ 1 root root 0 May 20 15:51 test2.dir/file.2
0:user:gozer:write_data:deny
1:user:gozer:read_data/write_data:allow
2:owner@:execute:deny
3:owner@:read_data/write_data/append_data/write_xattr/write_attributes
/write_acl/write_owner:allow
4:group@:write_data/append_data/execute:deny
5:group@:read_data:allow
6:everyone@:write_data/append_data/write_xattr/execute/write_attributes
/write_acl/write_owner:deny
7:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize
:allow
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Because the aclmode property for this file is set to the default value, groupmask, user gozer does not have write_data permission on file.2 because the file's group permission does not allow it.
When using the inherit_only permission, which is applied when the file_inherit or dir_inherit flag is set, is used to propagate the ACL through the directory structure. As such, user gozer is only granted or denied permission from everyone@ permissions unless he is the file owner or a member of the file's group owner. For example:
# mkdir test2.dir/subdir.2
# ls -dv test2.dir/subdir.2
drwxr-xr-x+ 2 root root 2 May 20 15:52 test2.dir/subdir.2
0:user:gozer:list_directory/read_data/add_file/write_data:file_inherit
/inherit_only:allow
1:owner@::deny
2:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
3:group@:add_file/write_data/add_subdirectory/append_data:deny
4:group@:list_directory/read_data/execute:allow
5:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
6:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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The following examples identify the file and directory ACLs that are applied when both the file_inherit and dir_inherit flags are set.
In this example, user gozer is granted read, write, and execute permissions that are inherited for newly created files and directories:
# chmod A+user:gozer:read_data/write_data/execute:file_inherit/dir_inherit:allow
test3.dir
# ls -dv test3.dir
drwxr-xr-x+ 2 root root 2 May 20 15:53 test3.dir
0:user:gozer:list_directory/read_data/add_file/write_data/execute
:file_inherit/dir_inherit:allow
1:owner@::deny
2:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
3:group@:add_file/write_data/add_subdirectory/append_data:deny
4:group@:list_directory/read_data/execute:allow
5:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
6:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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# touch test3.dir/file.3
# ls -v test3.dir/file.3
-rw-r--r--+ 1 root root 0 May 20 15:58 test3.dir/file.3
0:user:gozer:write_data/execute:deny
1:user:gozer:read_data/write_data/execute:allow
2:owner@:execute:deny
3:owner@:read_data/write_data/append_data/write_xattr/write_attributes
/write_acl/write_owner:allow
4:group@:write_data/append_data/execute:deny
5:group@:read_data:allow
6:everyone@:write_data/append_data/write_xattr/execute/write_attributes
/write_acl/write_owner:deny
7:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize
:allow
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# mkdir test3.dir/subdir.1
# ls -dv test3.dir/subdir.1
drwxr-xr-x+ 2 root root 2 May 20 15:59 test3.dir/subdir.1
0:user:gozer:list_directory/read_data/add_file/write_data/execute
:file_inherit/dir_inherit/inherit_only:allow
1:user:gozer:add_file/write_data:deny
2:user:gozer:list_directory/read_data/add_file/write_data/execute:allow
3:owner@::deny
4:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
5:group@:add_file/write_data/add_subdirectory/append_data:deny
6:group@:list_directory/read_data/execute:allow
7:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
8:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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In these examples, because the permissions of the parent directory for group@ and everyone@ deny write and execute permissions, user gozer is denied write and execute permissions. The default aclinherit property is restricted, which means that write_data and execute permissions are not inherited.
In this example, user gozer is granted read, write, and execute permissions that are inherited for newly created files. However, they are not propagated to subsequent contents of the directory.
# chmod A+user:gozer:read_data/write_data/execute:file_inherit/no_propagate:allow
test4.dir
# ls -dv test4.dir
drwxr-xr-x+ 2 root root 2 May 20 16:02 test4.dir
0:user:gozer:list_directory/read_data/add_file/write_data/execute
:file_inherit/no_propagate:allow
1:owner@::deny
2:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
3:group@:add_file/write_data/add_subdirectory/append_data:deny
4:group@:list_directory/read_data/execute:allow
5:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
6:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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As the following example shows, when a new subdirectory is created, user gozer's read_data/write_data/execute permissions for files are not propagated to the new sub4.dir directory:
mkdir test4.dir/sub4.dir
# ls -dv test4.dir/sub4.dir
drwxr-xr-x 2 root root 2 May 20 16:03 test4.dir/sub4.dir
0:owner@::deny
1:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
2:group@:add_file/write_data/add_subdirectory/append_data:deny
3:group@:list_directory/read_data/execute:allow
4:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
5:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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As the following example shows, user gozer's read_data/write_data/execute permissions for files are propagated to the newly created file:
# touch test4.dir/file.4
# ls -v test4.dir/file.4
-rw-r--r--+ 1 root root 0 May 20 16:04 test4.dir/file.4
0:user:gozer:write_data/execute:deny
1:user:gozer:read_data/write_data/execute:allow
2:owner@:execute:deny
3:owner@:read_data/write_data/append_data/write_xattr/write_attributes
/write_acl/write_owner:allow
4:group@:write_data/append_data/execute:deny
5:group@:read_data:allow
6:everyone@:write_data/append_data/write_xattr/execute/write_attributes
/write_acl/write_owner:deny
7:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize
:allow
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Example 8–7 ACL Inheritance With aclmode Property Set to passthrough
As the following example shows, when the aclmode property on the tank/cindys file system is set to passthrough, user gozer inherits the ACL applied on the test4.dir directory for the newly created file.4:
# zfs set aclmode=passthrough tank/cindys
# touch test4.dir/file.4
# ls -v test4.dir/file.4
-rw-r--r--+ 1 root root 0 May 20 16:08 test4.dir/file.4
0:user:gozer:write_data/execute:deny
1:user:gozer:read_data/write_data/execute:allow
2:owner@:execute:deny
3:owner@:read_data/write_data/append_data/write_xattr/write_attributes
/write_acl/write_owner:allow
4:group@:write_data/append_data/execute:deny
5:group@:read_data:allow
6:everyone@:write_data/append_data/write_xattr/execute/write_attributes
/write_acl/write_owner:deny
7:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize
:allow
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This output shows that the read_data/write_data/execute:allow:file_inherit/dir_inherit ACL that was set on the parent directory, test4.dir, is passed through to user gozer.
Example 8–8 ACL Inheritance With aclmode Property Set to discard
If the aclmode property on a file system is set to discard, then ACLs can potentially be discarded when the permissions on a directory change. For example:
# zfs set aclmode=discard tank/cindys
# chmod A+user:gozer:read_data/write_data/execute:dir_inherit:allow test5.dir
# ls -dv test5.dir
drwxr-xr-x+ 2 root root 2 May 20 16:09 test5.dir
0:user:gozer:list_directory/read_data/add_file/write_data/execute
:dir_inherit:allow
1:owner@::deny
2:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
3:group@:add_file/write_data/add_subdirectory/append_data:deny
4:group@:list_directory/read_data/execute:allow
5:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
6:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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If, at a later time, you decide to tighten the permissions on a directory, the non-trivial ACL is discarded. For example:
# chmod 744 test5.dir
# ls -dv test5.dir
drwxr--r-- 2 root root 2 May 20 16:09 test5.dir
0:owner@::deny
1:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
2:group@:add_file/write_data/add_subdirectory/append_data/execute:deny
3:group@:list_directory/read_data:allow
4:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/execute/write_attributes/write_acl/write_owner:deny
5:everyone@:list_directory/read_data/read_xattr/read_attributes/read_acl
/synchronize:allow
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Example 8–9 ACL Inheritance With the aclinherit Property Set to noallow
In the following example, two non-trivial ACLs with file inheritance are set. One ACL allows read_data permission, and one ACL denies read_data permission. This example also shows how you can specify two ACEs in the same chmod command.
# zfs set aclinherit=noallow tank/cindys
# chmod A+user:gozer:read_data:file_inherit:deny,user:lp:read_data:file_inherit:allow
test6.dir
# ls -dv test6.dir
drwxr-xr-x+ 2 root root 2 May 20 16:11 test6.dir
0:user:gozer:read_data:file_inherit:deny
1:user:lp:read_data:file_inherit:allow
2:owner@::deny
3:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
4:group@:add_file/write_data/add_subdirectory/append_data:deny
5:group@:list_directory/read_data/execute:allow
6:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
7:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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As the following example shows, when a new file is created, the ACL that allows read_data permission is discarded.
# touch test6.dir/file.6
# ls -v test6.dir/file.6
-rw-r--r-- 1 root root 0 May 20 16:13 test6.dir/file.6
0:owner@:execute:deny
1:owner@:read_data/write_data/append_data/write_xattr/write_attributes
/write_acl/write_owner:allow
2:group@:write_data/append_data/execute:deny
3:group@:read_data:allow
4:everyone@:write_data/append_data/write_xattr/execute/write_attributes
/write_acl/write_owner:deny
5:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize
:allow
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