.TH SLAPO-NSSOV 5 "RELEASEDATE" "OpenLDAP LDVERSION" .\" Copyright 1998-2009 The OpenLDAP Foundation, All Rights Reserved. .\" Copying restrictions apply. See the COPYRIGHT file. .\" $OpenLDAP$ .SH NAME slapo-nssov \- NSS lookup requests through a local Unix Domain socket .SH SYNOPSIS ETCDIR/slapd.conf .SH DESCRIPTION The .B nssov overlay to .BR slapd (8) allows NSS lookup requests through a local Unix Domain socket. It uses the same IPC protocol as Arthur de Jong's nss-ldapd, and a complete copy of the nss-ldapd source is included here. It also handles PAM requests. .LP The main objective here was to eliminate the libldap dependencies/clashes that the current pam_ldap/nss_ldap solutions all suffer from. A secondary objective was to allow for the possibility of more sophisticated caching than nscd provides. (E.g., run slapd back-ldap + pcache on each node.) Of course, you can also completey eliminate cache staleness considerations by running a regular database with syncrepl. .LP And of course, another major objective was to allow all security policy to be administered centrally via LDAP, instead of having fragile rules scattered across multiple flat files. As such, there is no client-side configuration at all for the pam/nss stub libraries. (They talk to the server via a Unix domain socket whose path is hardcoded to /var/run/nslcd/). As a side benefit, this can finally eliminate the perpetual confusion over /etc/ldap.conf vs /etc/openldap/ldap.conf. .LP User authentication is performed by internal simple Binds. User authorization leverages the slapd ACL engine, which offers much more power and flexibility than the simple group/hostname checks in the old pam_ldap code. .LP To use this code, you will need the client-side stub library from nss-ldapd (which resides in nss-ldapd/nss). You will not need the nslcd daemon; this overlay replaces that part. You should already be familiar with the [RFC2307] and [RFC2307bis] schema to use this overlay. See the .B nss-ldapd/README for more information on the schema and which features are supported. .LP To use the overlay add: .LP .RS .nf include nis.schema moduleload nssov.so ... database hdb ... overlay nssov .fi .RE .LP to your slapd configuration file. (The nis.schema file contains the original [RFC2307] schema. Some modifications will be needed to use [RFC2307bis].) .LP The overlay may be configured with .B Service Search Descriptors (SSDs) for each NSS service that will be used. SSDs are configured using .LP .RS .nf nssov-ssd .fi .RE .LP where the may be one of .LP .RS .nf alias ether group host netgroup network passwd protocol rpc service shadow .fi .RE .LP and the must be of the form .LP .RS .nf ldap:///[][??[][?]] .fi .RE .LP The .B will default to the first suffix of the current database. The .B defaults to "subtree". The default .B depends on which service is being used. .LP If the local database is actually a proxy to a foreign LDAP server, some mapping of schema may be needed. Some simple attribute substitutions may be performed using .LP .RS .nf nssov-map .fi .RE .LP See the .B nss-ldapd/README for the original attribute names used in this code. .LP The overlay also supports dynamic configuration in cn=config. The layout of the config entry is .LP .RS .nf dn: olcOverlay={0}nssov,ocDatabase={1}hdb,cn=config objectClass: olcOverlayConfig objectClass: olcNssOvConfig olcOverlay: {0}nssov olcNssSvc: passwd ldap:///ou=users,dc=example,dc=com??one olcNssMap: passwd uid accountName .fi .RE .LP which enables the passwd service, and uses the accountName attribute to fetch what is usually retrieved from the uid attribute. .LP PAM authentication, account management, session management, and password management are supported. .LP Authentication is performed using Simple Binds. Since all operations occur inside the slapd overlay, "fake" connections are used and they are inherently secure. Two methods of mapping the PAM username to an LDAP DN are provided: the mapping can be accomplished using slapd's authz-regexp facility. In this case, a DN of the form .B cn=+uid=,cn=,cn=pam,cn=auth is fed into the regexp matcher. If a match is produced, the resulting DN is used. Otherwise, the NSS passwd map is invoked (which means it must already be configured). .LP If no DN is found, the overlay returns PAM_USER_UNKNOWN. If the DN is found, and Password Policy is supported, then the Bind will use the Password Policy control and return expiration information to PAM. .LP Account management also uses two methods. These methods depend on the ldapns.schema included with the nssov source. .LP The first is identical to the method used in PADL's pam_ldap module: host and authorizedService attributes may be looked up in the user's entry, and checked to determine access. Also a check may be performed to see if the user is a member of a particular group. This method is pretty inflexible and doesn't scale well to large networks of users, hosts, and services. .LP The second uses slapd's ACL engine to check if the user has "compare" privilege on an ipHost object whose name matches the current hostname, and whose authorizedService attribute matches the current service name. This method is preferred, since it allows authorization to be centralized in the ipHost entries instead of scattered across the entire user population. The ipHost entries must have an authorizedService attribute (e.g. by way of the authorizedServiceObject auxiliary class) to use this method. .LP Session management: the overlay may optionally add a "logged in" attribute to a user's entry for successful logins, and delete the corresponding value upon logout. The attribute value is of the form .B () Password management: the overlay will perform a PasswordModify exop in the server for the given user. .SH FILES .TP ETCDIR/slapd.conf default slapd configuration file .SH SEE ALSO .BR slapd.conf (5), .BR slapd\-config (5), .BR slapd\-ldap (5), .BR slapd (8). .SH AUTHOR Originally implemented by Howard Chu; man page Gavin Henry, Suretec Systems Ltd.