2 ACLs - Konfiguration and Infos vor Developpers
3 ==============================================
5 ACL support for AFP is implemented with NFSv4 ACLs. Few filesystems and fewer OSes support
6 these. At the time of implementation its only provided with ZFS on Solaris, Opensolaris and
12 In order to be able to support ACLs, the following things have to be configured:
15 2. Authentication Domain
20 You MUST configure two ACL parameters for any volume you want to use with Netatalk:
22 aclinherit = passthrough
25 For an explanation of what these parameters mean and how to apply them see, your hosts
26 ZFS documentation (e.g. man zfs).
28 2. Authentication Domain
30 Your server and the clients must be part of a security association where identity data
31 is coming from a common source. ACLs in Darwin are based on UUIDs and so is the ACL
32 specification in AFP 3.2. Therefor your source of identity data has to provide an
33 attribute for every user and group where a UUID is stored as a ASCII string.
36 - you need an Open Directory Server or an LDAP server where you store UUIDs in some
38 - your clients must be configured to use this server
39 - your server should be configured to use this server via nsswitch and PAM. This
40 however is not a strict requirement:
41 if you create duplicates of every LDAP/OD user and group with identic attributes
42 (name, uid, gid) in your local data store (/etc/[passwd|group]) things will work
44 * as long as user/group names/ids in the filesystem are equal *
45 * to their counterparts in the LDAP/OD datastore *
47 - configure Netatalk via ldap.conf so that Netatalk is able to retrieve the UUID
48 for users and groups via LDAP search queries
52 Finally you can add "options:acls" to your volume defintions to add ACL support.
53 In case your volume basedir doesn't grant read permissions via mode (like: 0700 root:adm)
54 but only via ACLs, you MUST add the "nostat" option to the volume defintion.
59 Some implementation details that are buried in the code are worthwhile to be documented.
61 1. Darwin ACEs vs NFSv4 ACEs
62 2. .AppleDouble VFS integration
64 1. Darwin ACEs vs NFSv4 ACEs
66 Basically as far as implementing AFP support is concerned they're equivalent.
67 Subtleties arise at other places:
71 The AFP client frequently checks the (DARWIN_)ACE_DELETE_CHILD right. This is most
72 often not explicitly granted via an ACE. Therefor the client would get an no access
73 error. The client in turn then declares the object in question read only.
74 Thus we have to the check the mode for every directory and add ACE_DELETE_CHILD if
75 the requestor has write permissions.
79 10.5 does not only use unix mode and FPAccess for permission check, but also OS 9
80 access bits from FPGetFileDirParms. Thus we have to adjust the Access Rights bitmap
81 user bits by including any ACL rigths.
83 2. .AppleDouble VFS integration
85 FPSetACL sets ACLs on files and dirs. Our implementation also sets the same ACL on the
86 .AppleDouble file for files and on the .AppleDouble dir itself for dirs.
88 Thereafter ACLs for created files is taken care of by ACLs own inheritance rules.
90 For dirs on the other hand whe have to make sure that any ACL the dir inherits is
91 copied verbatim to its .AppleDouble dir.
94 January 2009, Frank Lahm