On 9/15/2020 10:07 AM, Matej Tyc wrote:
On 14. 09. 20 22:46, Daniel Miller wrote:
On 9/14/2020 1:19 PM, Matej Tyc wrote:
...
When learning about how ACL work in e.g.
[...] so I can't use
it to reverse-engineer the correct syntax.
The global ACLs are...global. They apply to all matching mailboxes
system-wide. So to answer your question, yes "* user=foo lrw" means
all mailboxes of all accounts are shared to the user foo. But...
Great, what about the format itself? Is it
<namespace>/<account>/<mailbox>? The documentation brings up, i.e.
/[email protected]/* shares all mailboxes of John from the example.com
domain? Or have I overlooked a documentation page where the syntax is
introduced?
No. You need to read the docs again:
https://doc.dovecot.org/settings/plugin/acl/
Global ACLs live in their own little space - either filesystem based or
file based. You specify who is *granted* global access - and the level
of that global access applies system-wide. So if you grant
"[email protected]" global read/write access to all Inboxes - John will
be able to access every Inbox of every user (however, he might not know
that a given inbox exists - without explicit configuration or explicit
sharing which updates the dictionary).
Next what https://wiki.dovecot.org/SharedMailboxes/Shared and
https://wiki.dovecot.org/Dictionary describe is a possibility to
reference LDAP data to define an ACL dictionary. Do I understand it
correctly that if a LDAP database is the single source of truth, then
I don't have to worry about updating dictionaries as long as LDAP
itself is up-to-date, but I have to keep ACLs and LDAP in sync
manually (or using an application)?
Again, a dictionary is a list of shared mailboxes - not ACL's. You can
use any dictionary source Dovecot can read from - but if the
dictionary also supports writing then any manipulation of ACLs will
automatically update the dictionary.
What the above implies, and I will now state explicitly, is that while
global ACLs provide *access* they do not *publish* that access. A
dictionary must be manually updated to list those mailboxes.
What I understand is that ACLs are purely filesystem-based, i.e. no LDAP
backend, and one has to sync LDAP to respective ACLs "manually".
If I follow what you have said, one could have an equal result with a
database, syncing ACLs "manually" from LDAP, and doveadm will make sure
that the database backend will be up-to-date.
First, I provide the disclaimer that I don't use LDAP. I had it years
ago and I'm quite happy to leave it behind. So I can't give you current
LDAP/Dovecot experience. However, a quick read of the page you reference
shows LDAP is read-only. Which means while you could theoretically use
LDAP for a global ACL source - trying to use it for per-user shares
would require quite a bit of manual effort for every change. I believe
the technical term for such a setup is "masochistic".
I totally understand the desire to have a single database for general
config purposes - however I think you're trying to use a power drill as
a hammer. Leave your authentication database, i.e. LDAP, alone and let
your mail server do its thing. Consider the mail store an entity as a
whole - not just the messages, but the format, the folder structure, and
the ACLs as a "black box" and I think you'll save yourself a lot of
frustration. Dovecot (in my own uninformed opinion) is designed to be
(mostly) autonomous and file-based - any database support is just for
user/passwords and leave it at that.
If you want per-user shares just use the example at the top of the wiki
page. From my own config:
plugin {
acl = vfile
acl_shared_dict = file:/var/mail/%d/shared-mailboxes
}
based on a mail_location of "sdbox:/var/mail/%d/%n/sdbox".
--
Daniel
