Pigeonhole Sieve: LDAP Lookup for Sieve Scripts
===============================================

The 'ldap' <location type> [Pigeonhole.Sieve.Configuration.txt] is used to
retrieve Sieve scripts from an LDAP database. To retrieve a Sieve script from
the LDAP database, at most two lookups are performed. First, the LDAP entry
containing the Sieve script is searched using the specified LDAP search filter.
If the LDAP entry changed since it was last retrieved (or it was never retieved
before), the attribute containing the actual Sieve script is retrieved in a
second lookup. In the first lookup, a special attribute is read and checked for
changes. Usually, this is the 'modifyTimestamp' attribute, but an alternative
can be configured.

Note that, by default, compiled binaries are not stored at all for Sieve
scripts retrieved from an LDAP database. The ';bindir=<path>' option needs to
be specified in the <location specification>
[Pigeonhole.Sieve.Configuration.txt].

Depending on how Pigeonhole was configured and compiled (refer to INSTALL file
for more information), LDAP support may only be available when a plugin called
'sieve_storage_ldap' is loaded.

Configuration
-------------

If support for the 'ldap' location type is compiled as a plugin, it needs to be
added to the sieve_plugins setting before it can be used, e.g.:

---%<-------------------------------------------------------------------------
sieve_plugins = sieve_storage_ldap
---%<-------------------------------------------------------------------------

The 'ldap' script location syntax is specified as follows:

---%<-------------------------------------------------------------------------
location = ldap:<config-file>[;<option>[=<value>][;...]]
---%<-------------------------------------------------------------------------

The '<config-file>' is a filesystem path that points to a configuration file
containing the actual configuration for this 'ldap' script location.

The following additional location options are recognized:

user=<username> :
  Overrides the user name used for the lookup. Normally, the name of the user
  running the Sieve interpreter is used.

If the name of the Script is left unspecified and not otherwise provided by the
Sieve interpreter, the name defaults to `'default''.

The configuration file is based on the auth userdb/passdb LDAP configuration
[http://wiki2.dovecot.org/AuthDatabase/LDAP]. The following options are
specific to the Sieve ldap location type:

sieve_ldap_filter = (&(objectClass=posixAccount)(uid=%u)) :
  The LDAP search filter that is used to find the entry containing the Sieve
  script.

sieve_ldap_script_attr = mailSieveRuleSource :
  The name of the attribute containing the Sieve script itself.

sieve_ldap_mod_attr = modifyTimestamp :
  The name of the attribute used to detect modifications to the LDAP entry.

Example
-------

The dovecot configuration:

---%<-------------------------------------------------------------------------
plugin {
  sieve = ldap:/etc/dovecot/sieve-ldap.conf;bindir=~/.sieve-bin/
}
---%<-------------------------------------------------------------------------

The contents of sieve-ldap.conf:

---%<-------------------------------------------------------------------------
# This file needs to be accessible by the Sieve interpreter running in
LDA/LMTP.
# This requires acces by the mail user. Don't use privileged LDAP credentials
# here as these may likely leak. Only search and read access is required.

# Space separated list of LDAP hosts to use. host:port is allowed too.
hosts = localhost

# Distinguished Name - the username used to login to the LDAP server.
# Leave it commented out to bind anonymously.
dn = cn=sieve,ou=Programs,dc=example,dc=org

# Password for LDAP server, if dn is specified.
dnpass = secret

# Simple binding.
sasl_bind = no

# No TLS
tls = no

# LDAP library debug level as specified by LDAP_DEBUG_* in ldap_log.h.
# -1 = everything. You may need to recompile OpenLDAP with debugging enabled
# to get enough output.
debug_level = 0

# LDAP protocol version to use. Likely 2 or 3.
ldap_version = 3

# LDAP base
base = dc=mail,dc=example,dc=org

# Dereference: never, searching, finding, always
deref = never

# Search scope: base, onelevel, subtree
scope = subtree

# Filter for user lookup. Some variables can be used:
#   %u      - username
#   %n      - user part in user@domain, same as %u if there's no domain
#   %d      - domain part in user@domain, empty if there's no domain
#   %{name} - name of the Sieve script
sieve_ldap_filter = (&(objectClass=posixAccount)(uid=%u))

# Attribute containing the Sieve script
sieve_ldap_script_attr = mailSieveRuleSource

# Attribute used for modification tracking
sieve_ldap_mod_attr = modifyTimestamp
---%<-------------------------------------------------------------------------

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