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 one ACL parameter for any volume you want to use with Netatalk:
22 aclinherit = passthrough
24 For an explanation of what these parameters mean and how to apply them see, your hosts
25 ZFS documentation (e.g. man zfs).
27 2. Authentication Domain
29 Your server and the clients must be part of a security association where identity data
30 is coming from a common source. ACLs in Darwin are based on UUIDs and so is the ACL
31 specification in AFP 3.2. Therefor your source of identity data has to provide an
32 attribute for every user and group where a UUID is stored as a ASCII string.
35 - you need an Open Directory Server or an LDAP server where you store UUIDs in some
37 - your clients must be configured to use this server
38 - your server should be configured to use this server via nsswitch and PAM
39 - configure Netatalk via afp_ldap.conf so that Netatalk is able to retrieve the UUID
40 for users and groups via LDAP search queries
44 Finally you can add "options:acls" to your volume defintions to add ACL support.
45 In case your volume basedir doesn't grant read permissions via mode (like: 0700 root:adm)
46 but only via ACLs, you MUST add the "nostat" option to the volume defintion.
51 Some implementation details that are buried in the code are worthwhile to be documented.
53 1. Darwin ACEs vs NFSv4 ACEs
54 2. .AppleDouble VFS integration
56 1. Darwin ACEs vs NFSv4 ACEs
58 Basically as far as implementing AFP support is concerned they're equivalent.
59 Subtleties arise at other places:
63 The AFP client frequently checks the (DARWIN_)ACE_DELETE_CHILD right. This is most
64 often not explicitly granted via an ACE. Therefor the client would get an no access
65 error. The client in turn then declares the object in question read only.
66 Thus we have to the check the mode for every directory and add ACE_DELETE_CHILD if
67 the requestor has write permissions.
71 10.5 does not only use unix mode and FPAccess for permission check, but also OS 9
72 access bits from FPGetFileDirParms. Thus we have to adjust the Access Rights bitmap
73 user bits by including any ACL rigths.
75 2. .AppleDouble VFS integration
77 FPSetACL sets ACLs on files and dirs. Our implementation also sets the same ACL on the
78 .AppleDouble file for files and on the .AppleDouble dir itself for dirs.
80 Thereafter ACLs for created files is taken care of by ACLs own inheritance rules.
82 For dirs on the other hand whe have to make sure that any ACL the dir inherits is
83 copied verbatim to its .AppleDouble dir.
86 January 2009, Frank Lahm