Adding upstream version 2.4.57+dfsg.upstream/2.4.57+dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 316 insertions, 0 deletions

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+.TH SLAPO-NSSOV 5 "RELEASEDATE" "OpenLDAP LDVERSION"
+.\" Copyright 1998-2021 The OpenLDAP Foundation, All Rights Reserved.
+.\" Copying restrictions apply.  See the COPYRIGHT file.
+.\" $OpenLDAP$
+.SH NAME
+slapo-nssov \- NSS and PAM requests through a local Unix Domain socket
+.SH SYNOPSIS
+ETCDIR/slapd.conf
+.SH DESCRIPTION
+The
+.B nssov 
+overlay to
+.BR slapd (8)
+services NSS and PAM requests through a local Unix Domain socket. 
+It uses the same IPC protocol as Arthur de Jong's nss-pam-ldapd.
+An extract of the nss-ldapd source is included along with the
+nssov source code to allow the overlay to communicate with the
+nss-pam-ldapd client stubs.
+.LP
+Using a separate IPC protocol for NSS and PAM requests eliminates the
+libldap dependencies/clashes that the current pam_ldap/nss_ldap solutions
+all suffer from. Both the original nss-ldapd and this nssov solution
+are free from these library issues.
+.LP
+Unlike nss-pam-ldapd, since this overlay executes inside slapd it allows for
+the possibility of sophisticated caching, without any of the weaknesses of
+nscd and other related caching solutions. E.g., a remote LDAP database can
+be accessed using back-ldap with proxy caching (see
+.BR slapd-ldap (5)
+and
+.BR slapo-pcache (5)
+) to leverage back-ldap's
+connection pooling as well as pcache's persistent caching, to provide
+high performance and a measure of support for disconnected operation.
+Alternatively, cache considerations can be completely eliminated by running
+a regular database with syncrepl to maintain synchronization with a remote
+LDAP database.
+.LP
+Another major benefit of nssov is that it allows 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 NSS/PAM stub libraries. (The stubs talk to the server via a Unix
+domain socket whose path is hardcoded to NSLCDPATH). As a side benefit,
+this can finally eliminate the perpetual confusion between OpenLDAP's
+ldap.conf file in ETCDIR/ldap.conf and the similarly named files typically
+used by pam_ldap and nss_ldap.
+.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-pam-ldapd.  You can get it from:
+http://arthurdejong.org/nss-pam-ldapd
+You will not need the nslcd daemon; this overlay replaces that part.
+To disable building of the nslcd daemon in nss-pam-ldapd, add the
+--disable-nslcd option to the nss-pam-ldapd configure script. You
+should already be familiar with the RFC2307 and RFC2307bis schema
+to use this overlay.  See the nss-pam-ldapd README for more information
+on the schema and which features are supported.
+.LP
+You will also need to include the nis.schema in your slapd configuration
+for RFC2307 support. If you wish to use RFC2307bis you will need a slightly
+different schema. You will also need the ldapns.schema for PAM authorization
+management.
+.LP
+You must select
+.B ldap
+in the appropriate services in
+.I /etc/nsswitch.conf
+in order for these NSS features to take effect. Likewise, you must
+enable
+.B pam_ldap
+for the authenticate, account, session, and password services in
+.I /etc/pam.conf
+or
+.I /etc/pam.d
+for these PAM features to take effect.
+
+.TP
+.B overlay nssov
+This directive adds the nssov overlay to the current backend.
+.TP
+.B nssov-ssd <service> <url>
+This directive configures a Service Search Descriptor (SSD) for each NSS
+service that will be used.  The <service> may be one of
+.RS
+.nf
+    aliases
+    ethers
+    group
+    hosts
+    netgroup
+    networks
+    passwd
+    protocols
+    rpc
+    services
+    shadow
+.fi
+.RE
+and the <url> must be of the form
+.RS
+.TP
+.B ldap:///[<basedn>][??[<scope>][?<filter>]]
+.RE
+The 
+.B <basedn> 
+will default to the first suffix of the current database.
+The 
+.B <scope> 
+defaults to "subtree". The default 
+.B <filter> 
+depends on which service is being used.
+.TP
+.B nssov-map <service> <orig> <new>
+If the local database is actually a proxy to a foreign LDAP server, some
+mapping of schema may be needed. This directive allows some simple attribute
+substitutions to be performed. See the 
+.B nss-ldapd/README 
+for the original attribute names used in this code.
+.TP
+.B nssov-pam <option> [...]
+This directive determines a number of PAM behaviors. Multiple options may
+be used at once, and available levels are:
+.RS
+.RS
+.PD 0
+.TP
+.B userhost
+check host attribute in user entry for authorization
+.TP
+.B userservice
+check authorizedService attribute in user entry for authorization
+.TP
+.B usergroup
+check that user is a member of specific group for authorization
+.TP
+.B hostservice
+check authorizedService attribute in host entry for authorization
+.TP
+.B authz2dn
+use authz-regexp mapping to map uid to LDAP DN
+.TP
+.B uid2dn
+use NSS passwd SSD to map uid to LDAP DN
+.PD
+.RE
+
+Setting the
+.BR userhost ,
+.BR userservice ,
+and
+.B usergroup
+options duplicates the original pam_ldap authorization behavior.
+
+The recommended approach is to use
+.B hostservice
+instead. In this case, ipHost entries must be created for all hosts
+being managed, and they must also have the authorizedServiceObject
+class to allow authorizedService attributes to be used. Also the
+NSS host SSD must be configured so that ipHost entries can be found.
+Authorization is checked by performing an LDAP Compare operation
+looking for the PAM service name in the authorizedService attribute.
+.B slapd
+ACLs should be set to grant or deny
+.B Compare
+privilege to the appropriate users or groups as desired.
+
+If the
+.B authz2dn
+option is set then authz-regexp mappings will be used to map the
+PAM username to an LDAP DN. The authentication DN will be of the
+form
+.RS
+.B cn=<service>+uid=<user>,cn=<hostname>,cn=pam,cn=auth
+.RE
+
+If no mapping is found for this authentication DN, then this
+mapping will be ignored.
+
+If the
+.B uid2dn
+option is set then the NSS passwd SSD will be used to map the
+PAM username to an LDAP DN. The passwd SSD must have already been
+configured for this mapping to succeed.
+
+If neither the authz2dn nor the uid2dn mapping succeeds, the module
+will return a PAM_USER_UNKNOWN failure code. If both options are set,
+the authz mapping is attempted first; if it succeeds the uid2dn mapping
+will be skipped.
+
+By default only the
+.B uid2dn
+option is set.
+.RE
+.TP
+.B nssov-pam-defhost <hostname>
+Specify a default hostname to check if an ipHost entry for the current
+hostname cannot be found. This setting is only relevant if the 
+.B hostservice
+option has been set.
+.TP
+.B nssov-pam-group-dn <DN>
+Specify the DN of an LDAP group to check for authorization. The LDAP user
+must be a member of this group for the login to be allowed. There is no
+default value. This setting is only relevant if the
+.B usergroup
+option has been set.
+.TP
+.B nssov-pam-group-ad <attribute>
+Specify the attribute to use for group membership checks.
+There is no default value.  This setting is only relevant if the
+.B usergroup
+option has been set.
+.TP
+.B nssov-pam-min-uid <integer>
+Specify a minimum uid that is allowed to login. Users with a uidNumber
+lower than this value will be denied access. The default is zero, which
+disables this setting.
+.TP
+.B nssov-pam-max-uid <integer>
+Specify a maximum uid that is allowed to login. Users with a uidNumber
+higher than this value will be denied access. The default is zero, which
+disables this setting.
+.TP
+.B nssov-pam-template-ad <attribute>
+Specify an attribute to check in a user's entry for a template login name.
+The template login feature is used by FreeBSD's PAM framework. It can be
+viewed as a form of proxying, where a user can authenticate with one
+username/password pair, but is assigned the identity and credentials of
+the template user. This setting is disabled by default.
+.TP
+.B nssov-pam-template <name>
+Specify a default username to be used if no template attribute is found
+in the user's entry. The
+.B nssov-pam-template-ad
+directive must be configured for this setting to have any effect.
+.TP
+.B nssov-pam-session <service>
+Specify a PAM service name whose sessions will be recorded. For the
+configured services, logins will be recorded in the
+.TP
+.B nssov-pam-password-prohibit-message <message>
+Diable password change service and return the specified message to
+users.
+.TP
+.B nssov-pam-pwdmgr-dn <dn>
+Specify the dn of the password manager.
+.TP
+.B nssov-pam-pwdmgr-pwd <pwd>
+Specify the pwd of the password manager.
+.TP
+.B loginStatus
+operational attribute of the user's entry. The attribute's values are
+of the form
+.RS
+.RS
+.B <generalizedTime> <host> <service> <tty> (<ruser@rhost>)
+.RE
+.RE
+Upon logout the corresponding value will be deleted. This feature allows
+a single LDAP Search to be used to check which users are logged in across
+all the hosts of a network. The rootdn of the database is used to perform
+the updates of the loginStatus attribute, so a rootdn must already be
+configured for this feature to work. By default no services are configured.
+.LP
+The PAM functions support LDAP Password Policy as well. If the password
+policy overlay is in use (see
+.BR slapo-ppolicy (5)),
+policy
+information (e.g. password expiration, password quality, etc.)
+may be returned to the PAM client as a result of authentication,
+account management, and password modification requests.
+
+The overlay also supports dynamic configuration in cn=config. An example
+of the config entry is
+.LP 
+.RS
+.nf
+    dn: olcOverlay={0}nssov,ocDatabase={1}hdb,cn=config
+    objectClass: olcOverlayConfig
+    objectClass: olcNssOvConfig
+    olcOverlay: {0}nssov
+    olcNssSsd: passwd ldap:///ou=users,dc=example,dc=com??one
+    olcNssMap: passwd uid accountName
+    olcNssPam: hostservice uid2dn
+    olcNssPamDefHost: defaulthost
+    olcNssPamMinUid: 500
+    olcNssPamMaxUid: 32000
+    olcNssPamSession: login
+    olcNssPamSession: sshd
+.fi
+.RE
+.LP
+which enables the passwd service, and uses the accountName attribute to
+fetch what is usually retrieved from the uid attribute. It also enables
+some PAM authorization controls, and specifies that the PAM
+.B login
+and
+.B sshd
+services should have their logins recorded.
+.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 slapo\-pcache (5),
+.BR slapo\-ppolicy (5),
+.BR slapd (8).
+.SH AUTHOR
+Howard Chu, inspired by nss-ldapd by Arthur de Jong and pam_ldap by Luke Howard
+Enhancements by Ted C. Cheng, Symas Corp.