vfs_zfsacl — ZFS ACL samba module
vfs objects = zfsacl
This VFS module is part of the samba(7) suite.
The zfsacl VFS module is the home
for all ACL extensions that Samba requires for proper integration
with ZFS.
Currently the zfsacl vfs module provides extensions in following areas :
NFSv4 ACL Interfaces with configurable options for ZFS
NOTE:This module follows the posix-acl behaviour
and hence allows permission stealing via chown. Samba might allow at a later
point in time, to restrict the chown via this module as such restrictions
are the responsibility of the underlying filesystem than of Samba.
This module makes use of the smb.conf parameter acl map full control = acl map full control When set to yes (the default), this parameter will add in the FILE_DELETE_CHILD bit on a returned ACE entry for a file (not a directory) that already contains all file permissions except for FILE_DELETE and FILE_DELETE_CHILD. This can prevent Windows applications that request GENERIC_ALL access from getting ACCESS_DENIED errors when running against a filesystem with NFSv4 compatible ACLs.
This module is stackable.
Since Samba 4.0 all options are per share options.
Controls substitution of special IDs (OWNER@ and GROUP@) on ZFS. The use of mode simple is recommended. In this mode only non inheriting ACL entries for the file owner and group are mapped to special IDs.
The following MODEs are understood by the module:
simple(default) - use OWNER@ and GROUP@ special IDs for non inheriting ACEs only.
special(deprecated) - use OWNER@ and GROUP@ special IDs in ACEs for all file owner and group ACEs.
This parameter configures how Samba handles duplicate ACEs encountered in ZFS ACLs. ZFS allows/creates duplicate ACE for different bits for same ID.
Following is the behaviour of Samba for different values :
dontcare (default) - copy the ACEs as they come
reject - stop operation and exit with error on ACL set op
ignore - don't include the second matching ACE
merge - bitwise OR the 2 ace.flag fields and 2 ace.mask fields of the 2 duplicate ACEs into 1 ACE
This parameter allows enabling or disabling the chown supported by the underlying filesystem. This parameter should be enabled with care as it might leave your system insecure.
Some filesystems allow chown as a) giving b) stealing. It is the latter that is considered a risk.
Following is the behaviour of Samba for different values :
yes - Enable chown if as supported by the under filesystem
no (default) - Disable chown
A ZFS mount can be exported via Samba as follows :
[samba_zfs_share]
vfs objects = zfsacl
path = /test/zfs_mount
nfs4: mode = special
nfs4: acedup = merge