Userdb LDAP
===========

Usually your LDAP database also contains the <userdb information>
[UserDatabase.txt]. If your home directory can be specified with a template and
you're using only a single <UID and GID> [UserIds.txt], you should use <static
userdb> [UserDatabase.Static.txt] instead to avoid an unnecessary LDAP lookup.
You can also use <prefetch userdb> [UserDatabase.Prefetch.txt] to avoid the
userdb LDAP lookup.

Userdb lookups are always done using the default DN ('dn' setting) bind. It's
not possible to do the lookup using the user's DN (remember that e.g. <LDA.txt>
needs to do userdb lookups without knowing the user's password).

The userdb lookups are configured in very much the same way as <LDAP password
lookups> [AuthDatabase.LDAP.PasswordLookups.txt]. Instead of 'pass_attrs' and
'pass_filter', the userdb uses 'user_attrs' and 'user_filter'. Typically
'pass_filter' and 'user_filter' are equivalent.

If you're using a single UID and GID for all the users, you can specify them
globally with 'mail_uid' and 'mail_gid' settings instead of returning them from
LDAP.

Example:

---%<-------------------------------------------------------------------------
user_attrs = \
  =home=%{ldap:homeDirectory}, \
  =uid=%{ldap:uidNumber}, \
  =gid=%{ldap:gidNumber}
user_filter = (&(objectClass=posixAccount)(uid=%u))

# For using doveadm -A:
iterate_attrs = =user=%{ldap:uid}
iterate_filter = (objectClass=posixAccount)
---%<-------------------------------------------------------------------------

Attribute templates (v2.1+)
---------------------------

You can mix static text with the value returned from LDAP by using %{ldap:*}
variables, which expand to the named LDAP attribute's value. Some examples:

Create a "quota_rule" field with value "*:bytes=<n>" where <n> comes from
"quotaBytes" LDAP attribute:

---%<-------------------------------------------------------------------------
user_attrs = \
  =quota_rule=*:bytes=%{ldap:quotaBytes}
---%<-------------------------------------------------------------------------

Create a "mail" field with value "maildir:/var/mail/<dir>/Maildir" where <dir>
comes from "sAMAccountName" LDAP attribute:

---%<-------------------------------------------------------------------------
user_attrs = \
  =mail=maildir:/var/spool/vmail/%{ldap:sAMAccountName}/Maildir
---%<-------------------------------------------------------------------------

You can add static fields that aren't looked up from LDAP. For example create a
"mail" field with value "maildir:/var/vmail/%d/%n/Maildir":

---%<-------------------------------------------------------------------------
user_attrs = \
  =quota_rule=*:bytes=%{ldap:quotaBytes}, \
  =mail=maildir:/var/vmail/%d/%n/Maildir
---%<-------------------------------------------------------------------------

If you don't want a field to exist at all when its LDAP attribute doesn't
exist, you can give the attribute name before the first "=" character. For
example this doesn't return "home" or "mail" fields if "mailboxPath" doesn't
exist:

---%<-------------------------------------------------------------------------
user_attrs = \
  =quota_rule=*:bytes=%{ldap:quotaBytes}, \
  mailboxPath=home=/home/%{ldap:mailboxPath}, \
  mailboxPath=mail=maildir:~/Maildir
---%<-------------------------------------------------------------------------

It's also possible to give default values to nonexistent attributes in v2.1.11+
by using e.g.'%{ldap:userDomain:example.com} ' where if userDomain attribute
doesn't exist, example.com is used instead.

Subqueries and pointers (v2.2)
------------------------------

LDAP values can now have DN pointers to other entries that are queried.

*Note*: These aren't actually very useful anymore. See the next section for how
to do multiple queries more easily using multiple userdbs.

Example:

---%<-------------------------------------------------------------------------
user_attrs = \
  =user=%{ldap:uid}, \
  @mail=%{ldap:mailDN}, \
  =uid=%{ldap:uidNumber@mail}, \
  =gid=%{ldap:gidNumber@mail}, \
  =home=%{ldap:rootPath@mail}/%d/%n
---%<-------------------------------------------------------------------------

This will do a regular lookup first. Then does another lookup with DN taken
from mailDN's value. The *@mail attributes are assigned from the second
lookup's results.

---%<-------------------------------------------------------------------------
user_attrs = \
  =user=%{ldap:uid}, \
  =home=%{ldap_ptr:activePath}, \
  !primaryPath, !secondaryPath
---%<-------------------------------------------------------------------------

The activePath's value can be either "primaryPath" or "secondaryPath". The
home's value will be the contents of that field. The !field tells Dovecot to
fetch the field's value but not to do anything with it otherwise.

Multiple queries via userdbs (v2.2+)
------------------------------------

Example: Give the user a class attribute, which defines the default quota:

dovecot.conf:

---%<-------------------------------------------------------------------------
userdb {
  driver = ldap
  args = /etc/dovecot/dovecot-users-ldap.conf.ext
  result_success = continue-ok
}
userdb {
  driver = ldap
  args = /etc/dovecot/dovecot-class-ldap.conf.ext
  skip = notfound
}
---%<-------------------------------------------------------------------------

/etc/dovecot/dovecot-users-ldap.conf.ext:

---%<-------------------------------------------------------------------------
# If user has overridden quota, quota_rule is set below. Otherwise it's still
unset.
user_attrs = \
  =class=%{ldap:userClass}
  quotaBytes=quota_rule=*:bytes=%{ldap:quotaBytes}
---%<-------------------------------------------------------------------------

/etc/dovecot/dovecot-class-ldap.conf.ext:

---%<-------------------------------------------------------------------------
# Do the lookup using the user's class:
user_filter = (&(objectClass=userClass)(class=%{userdb:class}))
# With :protected suffix the quota_rule isn't overridden if it's already set.
user_attrs = \
  classQuotaBytes=quota_rule:protected=*:bytes=%{ldap:classQuotaBytes}
---%<-------------------------------------------------------------------------

Variables and domains
---------------------

User names and domains may be distinguished using the <Variables.txt> %n and
%d.  They split the /previous username/ at the "@" character.  The /previous
username/ is:

 * For LMTP, it will be user@hostname, where hostname depends on e.g. the
   Postfix configuration.
 * For IMAP, it will be whatever the password database has designated as the
   username.  If the (LDAP) password database has "user_attrs = =user=%n", then
   the domain part of the login name will be stripped by the password database.
    The UserDB will not see any domain part, i.e. %n and %u are the same thing
   for the UserDB.

The UserDB may set a new username, too, using "user_attrs = =user=...".  This
will be used for

 * Logging
 * %u and %d variables in other parts of the configuration (e.g. quota file
   names)

(This file was created from the wiki on 2019-06-19 12:42)