ProFTPD module mod_ldap

## ProFTPD module `mod_ldap`

This module is contained in the `mod_ldap.c` file for ProFTPD 1.2.x/1.3.x, and is not compiled by default. Installation instructions are discussed here.

The most current version of `mod_ldap` is distributed with the ProFTPD source code.

## Author

Please contact John Morrissey <jwm at horde.net> with any questions, concerns, or suggestions regarding this module.

## Directives

- LDAPAliasDereference
- LDAPAttr
- LDAPAuthBinds
- LDAPDNInfo
- LDAPDefaultAuthScheme
- LDAPDefaultGID
- LDAPDefaultUID
- LDAPDoAuth
- LDAPDoGIDLookups
- LDAPDoQuotaLookups
- LDAPDoUIDLookups
- LDAPForceDefaultGID
- LDAPForceDefaultUID
- LDAPForceGeneratedHomedir
- LDAPGenerateHomedir
- LDAPGenerateHomedirPrefix
- LDAPGenerateHomedirPrefixNoUsername
- LDAPNegativeCache
- LDAPProtocolVersion
- LDAPQueryTimeout
- LDAPSearchScope
- LDAPServer
- LDAPUseSSL
- LDAPUseTLS

## LDAPAliasDereference

Syntax: LDAPAliasDereference never|always|search|find
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

The `LDAPAliasDereference` directive configures how aliases are handled. The possible values have the following behaviors:

- never

  Never dereference aliases

- always

  Always dereference aliases

- search

  Dereference aliases only when searching

- find

  Dereference aliases only when locating the base object for the search

The default is "never", e.g.:

      <IfModule mod_ldap.c>
        LDAPAliasDeference never
      </IfModule>

## LDAPAttr

Syntax: LDAPAttr old-attr-name new-attr-name
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

The `LDAPAttr` directive is used to map, or to associate, a standard attribute name to a non-standard attribute name. If, for example, your LDAP directory schema used different names for some of the attributes used by `mod_ldap`, you would use this directive to tell `mod_ldap` what new attribute names to use.

The following LDAP attributes can be renamed in this manner:

- `uid`
- `uidNumber`
- `gidNumber`
- `homeDirectory`
- `userPassword`
- `loginShell`
- `cn`
- `memberUid`
- `ftpQuota`

## LDAPAuthBinds

Syntax: LDAPAuthBinds on|off
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

By default, the DN specified by the `LDAPDNInfo` will be used to bind to the LDAP server to obtain user information, including the `userPassword` attribute. If `LDAPAuthBinds` is set to on, the DN specified by `LDAPDNInfo` will be used to fetch all user information except the `userPassword` attribute. Then, the `mod_ldap` module will bind to the LDAP server as the user who is logging in via FTP with the user-supplied password. If this bind succeeds, the user is considered authenticated and is allowed to log in. This method of LDAP authentication has the added benefit of supporting any password encryption scheme that your LDAP server supports.

In versions of `mod_ldap` up to 2.7.6, the default for `LDAPAuthBinds` was off. After `mod_ldap` 2.8, the default value for `LDAPAuthBinds` is on.

## LDAPDNInfo

Syntax: LDAPDNInfo dn password
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

The `LDAPDNInfo` directive configures the DN and the password that `mod_ldap` will use when binding to the LDAP directory. If this configuration directive is missing, then anonymous binds are used.

The default is:

      <IfModule mod_ldap.c>
        # Use anonymous binds
        LDAPDNInfo "" ""
      </IfModule>

See also: `LDAPServer`

## LDAPDefaultAuthScheme

Syntax: LDAPDefaultAuthScheme crypt|clear
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

The `LDAPDefaultAuthScheme` directive specifies the authentication scheme used for passwords which have no "{hashname}" prefix in the LDAP directory. For example, if you are:

      userPassword mypass

in your directory, you would want to set `LDAPDefaultAuthScheme` to clear.

The default value is crypt.

## LDAPDefaultGID

Syntax: LDAPDefaultGID gid
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

The `LDAPDefaultGID` directive sets the default GID to be used for users when no `gidNumber` attribute is found for that user.

This directive is useful primarily in virtual user environments common in large-scale ISPs and hosting organizations. If a user does not have an LDAP `gidNumber` attribute, the `LDAPDefaultGID` is used. This allows one to have a large number of users in an LDAP directory without `gidNumber` attributes; setting this configuration directive will automatically assign those users a single GID.

See also: `LDAPDefaultUID`

## LDAPDefaultUID

Syntax: LDAPDefaultUID uid
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

The `LDAPDefaultUID` directive sets the default UID to be used for users when no `uidNumber` attribute is found for that user.

This directive is useful primarily in virtual user environments common in large-scale ISPs and hosting organizations. If a user does not have an LDAP `uidNumber` attribute, the `LDAPDefaultGID` is used. This allows one to have a large number of users in an LDAP directory without `uidNumber` attributes; setting this configuration directive will automatically assign those users a single UID.

See also: `LDAPDefaultGID`

## LDAPDoAuth

Syntax: LDAPDoAuth off|on base-dn search-filter-template
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

The `LDAPDoAuth` configuration directive activates LDAP authentication. The second parameter to this directive is the LDAP base DN to use for authentication. The third parameter is a template to be used for the search filter; `%v` will be replaced with the username that is being authenticated.

By default, the search filter template used is:

      (&(uid=%v)(objectclass=posixAccount))

The uid for the the search filter is taken from the `LDAPAttr` directive. Search filter templates are only supported in versions of `mod_ldap` 2.7 and later.

See also: `LDAPAttr`

## LDAPDoGIDLookups

Syntax: LDAPDoGIDLookups off|on base-dn cn-filter-template gid-number-filter-template member-uid-filter-template
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

The `LDAPDoGIDLookups` directive activates LDAP GID-to-name lookups for directory listings. The second parameter to this directive is the LDAP base DN to use for GID-to-name lookups. The third through fifth parameters are templates to be used for the search filter; `%v` will be replaced with the GID that is being looked up.

By default, the CN filter template look like this:

      (&(LDAPAttr_cn=%v)(objectclass=posixGroup))

The `gidNumber` filter template is:

      (&(LDAPAttr_gidNumber=%v)(objectclass=posixGroup))

and the `memberUid` filter template used is: (&(LDAPAttr_memberUid=%v)(objectclass=posixGroup)) Note that filter templates are only supported in `mod_ldap` version 2.8.3 and later.

The attribute names used in the default search filters are taken from the `LDAPAttr` directive.

## LDAPDoQuotaLookups

Syntax: LDAPDoQuotaLookups off|on base-dn quota-filter-template default-quota
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

The `LDAPDoQuotaLookups` directive enables LDAP quota lookups. The second parameter of this directive is the LDAP base DN to use for quota limit search. The third parameter is a template to be used for the search filter; `%v` will be replaced with the username that is being authenticated.

By default, the search filter template is:

      (&(LDAPAttr_uid=%v)(objectclass=posixAccount))

The uid for the the search filter is taken from the `LDAPAttr` directive. Note that search filter templates are only supported in `mod_ldap` version 2.7 and later.

If specified, the default-quota parameter indicates the quota limits to use if a user does not have an `ftpQuota` attribute. This parameter is formatted the same way as the `ftpQuota` LDAP attribute.

## LDAPDoUIDLookups

Syntax: LDAPDoUIDLookups off|on base-dn uid-filter-template
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

The `LDAPDoUIDLookups` directive activates LDAP UID-to-name lookups for directory listings. The second parameter to this directive is the LDAP base DN to use for UID-to-name lookups. The third parameter is a template to be used for the search filter; `%v` will be replaced with the UID that is being looked up.

By default, the search filter template looks like this:

      (&(LDAPAttr_uidNumber=%v)(objectclass=posixGroup))

The uidNumber attribute name used in the search filter comes from the `LDAPAttr` directive. Note that filter templates are only supported in `mod_ldap` version 2.7 and later.

## LDAPForceDefaultGID

Syntax: LDAPForceDefaultGID on|off
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

Even when a `LDAPDefaultGID` is configured, the `mod_ldap` module will allow individual users to have `gidNumber` attributes that will override this default GID. With `LDAPForceDefaultGID` directive configured to be on, all LDAP-authenticated users are given the default GID; GIDs may not be overridden by `gidNumber` attributes.

## LDAPForceDefaultUID

Syntax: LDAPForceDefaultUID on|off
Default: None
Context: server config
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

Even when a `LDAPDefaultUID` is configured, the `mod_ldap` module will allow individual users to have `uidNumber` attributes that will override this default UID. With `LDAPForceDefaultUID` directive configured to be on, all LDAP-authenticated users are given the default UID; UIDs may not be overridden by `uidNumber` attributes.

## LDAPForceGeneratedHomedir

Syntax: LDAPForceGeneratedHomedir off|on directory-mode
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

See also: `LDAPGenerateHomedir`, `LDAPGenerateHomedirPrefix`, `LDAPGenerateHomedirPrefixNoUsername`

## LDAPGenerateHomedir

Syntax: LDAPGenerateHomedir on|off
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

## LDAPGenerateHomedirPrefix

Syntax: LDAPGenerateHomedirPrefix prefix
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

## LDAPGenerateHomedirPrefixNoUsername

Syntax: LDAPGenerateHomedirPrefixNoUsername on|off
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

## LDAPNegativeCache

Syntax: LDAPNegativeCache on|off
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

The `LDAPNegativeCache` directive specifies whether or not to cache negative responses from the LDAP server when using LDAP for UID/GID lookups. This option is useful if you also use/are in transition from another authentication system; if there are many users in your old authentication system that aren't in the LDAP database, there can be a significant delay when a directory listing is performed as the UIDs not in the LDAP database are repeatedly looked up in an attempt to present usernames instead of UIDs in directory listings. With `LDAPNegativeCache` set to on, negative ("not found") responses from the LDAP server will be cached and speed will improve on directory listings that contain many users not present in the LDAP database.

## LDAPProtocolVersion

Syntax: LDAPProtocolVersion 2|3
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

The `LDAPProtocolVersion` directive configures the version of the LDAP protocol that `mod_ldap` will use when talking to the LDAP servers. The default protocol version used is 3.

## LDAPQueryTimeout

Syntax: LDAPQueryTimeout secs
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

The `LDAPQueryTimeout` directive configures the timeout value, in seconds, that will be used for LDAP directory queries. The default timeout value is determined by your LDAP API.

## LDAPSearchScope

Syntax: LDAPSearchScope onelevel|subtree
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

The `LDAPSearchScope` directive is used to set the scope used for LDAP searches. The default setting, subtree, searches for all entries in the tree from the current level down. Setting this directive to onelevel searches only one level deep in the LDAP tree.

## LDAPServer

Syntax: LDAPServer "host1:port1 host2:port2"
Default: None
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

The `LDAPServer` directive allows you to to specify the hostname(s) and port(s) of the LDAP server(s) to use for LDAP authentication. If no `LDAPServer` configuration directive is present, the default LDAP servers specified by your LDAP library will be used.

To specify multiple LDAP servers, enclose the entire list of servers in quotation marks. For example:

      LDAPServer "host1:port1 host2:port2"

## LDAPUseSSL

Syntax: LDAPUseSSL on|off
Default: off
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.3.1rc1 and later

## LDAPUseTLS

Syntax: LDAPUseTLS on|off
Default: off
Context: server config, `<VirtualHost>`, `<Global>`
Module: mod_ldap
Compatibility: 1.2.7rc1 and later

The `LDAPUseTLS` directive configures whether `mod_ldap` will use SSL/TLS to protect the connections made to the configured LDAP servers.

By default, the `mod_ldap` module connects to the LDAP server via non-encrypted connections. Enabling this option causes `mod_ldap` to use an encrypted (TLS/SSL) connection to the LDAP server. If a secure connection to the LDAP server fails, `mod_ldap` will not authenticate users; `mod_ldap` will not fall back to an unsecure connection.

## Usage

## Installation

Follow the normal steps for using third-party modules in proftpd:

      ./configure --with-modules=mod_ldap
      make
      make install

You may need to specify the location of the OpenLDAP header and library files in your `configure command, e.g.:

     ./configure --with-modules=mod_ldap \
        --with-includes=/usr/local/openldap/include \
        --with-libraries=/usr/local/openldap/lib

## Usage

One `mod_ldap` user submitted the following configuration for allowing `mod_ldap` to communicate to a Windows Active Directory server. Note that this configuration has not been tested; if it works for you (or not), please let us know:

      <IfModule mod_ldap.c>
        LDAPServer dc.example.org:3268
        LDAPUseTLS on
        LDAPAuthBinds on
        LDAPDNInfo "cn=SRV_ACC_SVN_AUTH,ou=special accounts,ou=Sales,dc=example,dc=org" ******************

        LDAPDoAuth on ou=Users,ou=Sales,dc=example,dc=org "(&(sAMAccountName=%u)(objectclass=user)(memberOf=cn=Linux Admins,ou=Groups,ou=Sales,dc=example,DC=org))"
        LDAPSearchScope subtree

        # Assign default IDs
        LDAPDefaultUID 106
        LDAPDefaultGID 65534

        # Create the home directory
        LDAPGenerateHomedir on
        LDAPGenerateHomedirPrefix /home

        # Use different attribute names where necessary
        LDAPAttr uid sAMAccountName
        LDAPAttr gidNumber primaryGroupID

      </IfModule>

Author: $Author: castaglia $
Last Updated: $Date: 2008/08/15 22:16:54 $

© Copyright 2008 TJ Saunders
All Rights Reserved

`