how to configure and run the stand-alone {{TERM:LDAP}} daemon,
{{slapd}}(8) and the stand-alone LDAP update replication daemon,
{{slurpd}}(8). It is intended for newcomers and experienced
-administrators alike. This section provides a basic introduction to
-directory services and, in particular, the directory services provided
-by {{slapd}}(8).
+administrators alike. This section provides a basic introduction
+to directory services and, in particular, the directory services
+provided by {{slapd}}(8).
H2: What is a directory service?
-A directory is specialized database optimized for reading, browsing and
-searching. Directories tend to contain descriptive, attribute-based
-information and support sophisticated filtering capabilities. Directories
-generally do not support complicated transaction or roll-back schemes
-found in database management systems designed for handling high-volume
-complex updates. Directory updates are typically simple all-or-nothing
-changes, if they are allowed at all. Directories are tuned to give
-quick-response to high-volume lookup or search operations. They may have
-the ability to replicate information widely in order to increase
-availability and reliability, while reducing response time. When
-directory information is replicated, temporary inconsistencies between
-the replicas may be okay, as long as they get in sync eventually.
-
-There are many different ways to provide a directory service. Different
-methods allow different kinds of information to be stored in the directory,
-place different requirements on how that information can be referenced,
-queried and updated, how it is protected from unauthorized access, etc.
-Some directory services are {{local}}, providing service to a restricted
-context (e.g., the finger service on a single machine). Other services are
-global, providing service to a much broader context (e.g., the entire Internet).
-Global services are usually {{distributed}}, meaning that the data they
-contain is spread across many machines, all of which cooperate to provide
-the directory service. Typically a global service defines a uniform
-{{namespace}} which gives the same view of the data no matter where
-you are in relation to the data itself. The Internet {{TERM[expand]DNS}}
-is an example of a globally distributed directory service.
+A directory is specialized database optimized for reading, browsing
+and searching. Directories tend to contain descriptive, attribute-based
+information and support sophisticated filtering capabilities.
+Directories generally do not support complicated transaction or
+roll-back schemes found in database management systems designed
+for handling high-volume complex updates. Directory updates are
+typically simple all-or-nothing changes, if they are allowed at
+all. Directories are tuned to give quick-response to high-volume
+lookup or search operations. They may have the ability to replicate
+information widely in order to increase availability and reliability,
+while reducing response time. When directory information is
+replicated, temporary inconsistencies between the replicas may be
+okay, as long as they get in sync eventually.
+
+There are many different ways to provide a directory service.
+Different methods allow different kinds of information to be stored
+in the directory, place different requirements on how that information
+can be referenced, queried and updated, how it is protected from
+unauthorized access, etc. Some directory services are {{local}},
+providing service to a restricted context (e.g., the finger service
+on a single machine). Other services are global, providing service
+to a much broader context (e.g., the entire Internet). Global
+services are usually {{distributed}}, meaning that the data they
+contain is spread across many machines, all of which cooperate to
+provide the directory service. Typically a global service defines
+a uniform {{namespace}} which gives the same view of the data no
+matter where you are in relation to the data itself. The Internet
+{{TERM[expand]DNS}} is an example of a globally distributed directory
+service.
H2: What is LDAP?
-{{slapd}}'s model for directory service is based on a global directory
-model called {{TERM:LDAP}}. LDAP stands for {{TERM[expand]LDAP}}.
-LDAP is a directory access protocol that runs over
-{{TERM:TCP}}/{{TERM:IP}}. The nitty-gritty details of LDAP are defined in
+{{TERM:LDAP}} stands for {{TERM[expand]LDAP}}. As the name suggests,
+it is a lightweight protocol for accessing directory services,
+specifically {{TERM:X.500}}-based directory services. LDAP runs
+over {{TERM:TCP}}/{{TERM:IP}} or other connection oriented transfer
+services. The nitty-gritty details of LDAP are defined in
{{REF:RFC2251}} "The Lightweight Directory Access Protocol (v3)."
This section gives an overview of LDAP from a user's perspective.
-{{What kind of information can be stored in the directory?}}
-The LDAP information model is based on {{entries}}. An entry is a
-collection of attributes that has a globally-unique
-{{TERM[expand]DN}} (DN).
-The DN is used to refer to the entry unambiguously. Each of the
-entry's attributes has a {{type}} and one or more {{values}}.
-The types are typically mnemonic strings, like "{{EX:cn}}" for common
-name, or "{{EX:mail}}" for email address. The syntax of values depend
-on the attribute type is. For example, {{EX:cn}} attribute might
-be the value {{EX:Babs Jensen}}. A {{EX:mail}} attribute might
-contain the value "{{EX:babs@example.com}}". A {{EX:jpegPhoto}}
-attribute would contain a photograph in the JPEG (binary) format.
-
-{{How is the information arranged?}}
-In LDAP, directory entries are arranged in a hierarchical tree-like
-structure. Traditionally, this structure reflected the geographic
-and/or organizational boundaries. Entries representing countries
-appeared at the top of the tree. Below them are entries representing
-states and national organizations. Below them might be entries
-representing organizational units, people, printers, documents,
-or just about anything else you can think of. Figure 1.1 shows an
-example LDAP directory tree using traditional naming.
+{{What kind of information can be stored in the directory?}} The
+LDAP information model is based on {{entries}}. An entry is a
+collection of attributes that has a globally-unique {{TERM[expand]DN}}
+(DN). The DN is used to refer to the entry unambiguously. Each of
+the entry's attributes has a {{type}} and one or more {{values}}.
+The types are typically mnemonic strings, like "{{EX:cn}}" for
+common name, or "{{EX:mail}}" for email address. The syntax of
+values depend on the attribute type is. For example, {{EX:cn}}
+attribute might be the value {{EX:Babs Jensen}}. A {{EX:mail}}
+attribute might contain the value "{{EX:babs@example.com}}". A
+{{EX:jpegPhoto}} attribute would contain a photograph in the JPEG
+(binary) format.
+
+{{How is the information arranged?}} In LDAP, directory entries
+are arranged in a hierarchical tree-like structure. Traditionally,
+this structure reflected the geographic and/or organizational
+boundaries. Entries representing countries appeared at the top of
+the tree. Below them are entries representing states and national
+organizations. Below them might be entries representing organizational
+units, people, printers, documents, or just about anything else
+you can think of. Figure 1.1 shows an example LDAP directory tree
+using traditional naming.
!import "intro_tree.gif"; align="center"; \
title="LDAP directory tree (traditional naming)"
FT[align="Center"] Figure 1.1: LDAP directory tree (traditional naming)
-The tree may also be arranged based upon Internet domain names. This
-naming approach is becoming increasing popular as it allows for
-directory services to be locating using the {{TERM[expand]DNS}}.
+The tree may also be arranged based upon Internet domain names.
+This naming approach is becoming increasing popular as it allows
+for directory services to be locating using the {{TERM[expand]DNS}}.
Figure 1.2 shows an example LDAP directory tree using domain-based
naming.
FT[align="Center"] Figure 1.2: LDAP directory tree (Internet naming)
In addition, LDAP allows you to control which attributes are required
-and allowed in an entry through the use of a special attribute called
-{{EX:objectClass}}. The values of the {{EX:objectClass}} attribute
-determine the {{schema}} rules the entry must obey.
-
-{{How is the information referenced?}}
-An entry is referenced by its distinguished name, which is constructed
-by taking the name of the entry itself (called the {{TERM[expand]RDN}}
-or RDN) and concatenating the names of its ancestor entries. For
-example, the entry for Barbara Jensen in the Internet naming example
-above has an RDN of {{EX:uid=babs}} and a DN of
-{{EX:uid=babs,ou=People,dc=example,dc=com}}". The full DN format is
-described in {{REF:RFC2253}}, "Lightweight Directory Access Protocol (v3):
-UTF-8 String Representation of Distinguished Names."
-
-{{How is the information accessed?}}
-LDAP defines operations for interrogating and updating the directory.
-Operations are provided for adding and deleting
-an entry from the directory, changing an existing entry, and changing the
-name of an entry. Most of the time, though, LDAP is used to search for
-information in the directory. The LDAP search operation allows some portion
-of the directory to be searched for entries that match some criteria specified
-by a search filter. Information can be requested from each entry that matches
-the criteria.
-
-For example, you might want to search the entire directory subtree at
-and below {{EX:dc=example,dc=com}} for people with the name {{EX:Barbara
-Jensen}}, retrieving the email address of each entry found. LDAP lets
-you do this easily. Or you might want to search the entries directly
-below the {{EX:st=California,c=US}} entry for organizations with the
-string {{EX:Acme}} in their name, and that have a fax number. LDAP lets
-you do this too. The next section describes in more detail what you can
-do with LDAP and how it might be useful to you.
-
-{{How is the information protected from unauthorized access?}}
-Some directory services provide no protection, allowing anyone to see
+and allowed in an entry through the use of a special attribute
+called {{EX:objectClass}}. The values of the {{EX:objectClass}}
+attribute determine the {{schema}} rules the entry must obey.
+
+{{How is the information referenced?}} An entry is referenced by
+its distinguished name, which is constructed by taking the name of
+the entry itself (called the {{TERM[expand]RDN}} or RDN) and
+concatenating the names of its ancestor entries. For example, the
+entry for Barbara Jensen in the Internet naming example above has
+an RDN of {{EX:uid=babs}} and a DN of
+{{EX:uid=babs,ou=People,dc=example,dc=com}}". The full DN format
+is described in {{REF:RFC2253}}, "Lightweight Directory Access
+Protocol (v3): UTF-8 String Representation of Distinguished Names."
+
+{{How is the information accessed?}} LDAP defines operations for
+interrogating and updating the directory. Operations are provided
+for adding and deleting an entry from the directory, changing an
+existing entry, and changing the name of an entry. Most of the
+time, though, LDAP is used to search for information in the directory.
+The LDAP search operation allows some portion of the directory to
+be searched for entries that match some criteria specified by a
+search filter. Information can be requested from each entry that
+matches the criteria.
+
+For example, you might want to search the entire directory subtree
+at and below {{EX:dc=example,dc=com}} for people with the name
+{{EX:Barbara Jensen}}, retrieving the email address of each entry
+found. LDAP lets you do this easily. Or you might want to search
+the entries directly below the {{EX:st=California,c=US}} entry for
+organizations with the string {{EX:Acme}} in their name, and that
+have a fax number. LDAP lets you do this too. The next section
+describes in more detail what you can do with LDAP and how it might
+be useful to you.
+
+{{How is the information protected from unauthorized access?}} Some
+directory services provide no protection, allowing anyone to see
the information. LDAP provides a mechanisms for a client to
authenticate, or prove its identity to a directory server, paving
-the way for rich access control to protect the information the server
-contains. LDAP also supports privacy and integrity security
+the way for rich access control to protect the information the
+server contains. LDAP also supports privacy and integrity security
services.
H2: How does LDAP work?
-LDAP directory service is based on a {{client-server}} model. One or more
-LDAP servers contain the data making up the LDAP directory tree. An LDAP
-client connects to an LDAP server and asks it a question. The server
-responds with the answer and/or with a pointer to where the client can
-get additional information (typically, another LDAP server). No matter
-which LDAP server a client connects to, it sees the same view of the
-directory; a name presented to one LDAP server references the same
-entry it would at another LDAP server. This is an important feature of
-a global directory service, like LDAP.
+LDAP directory service is based on a {{client-server}} model. One
+or more LDAP servers contain the data making up the directory
+information tree (DIT). The client connects to servers and
+asks it a question. The server responds with an answer and/or
+with a pointer to where the client can get additional information
+(typically, another LDAP server). No matter which LDAP server a
+client connects to, it sees the same view of the directory; a name
+presented to one LDAP server references the same entry it would at
+another LDAP server. This is an important feature of a global
+directory service, like LDAP.
+
+
+H2: What about X.500?
+
+Technically, {{TERM:LDAP}} is a directory access protocol to an
+{{TERM:X.500}} directory service, the {{TERM:OSI}} directory service.
+Initially, LDAP clients accessed gateways to directory service.
+This gateway ran LDAP (between the client and gateway) and X.500's
+{{TERM[expand]DAP}} ({{TERM:DAP}}) (between the gateway and the
+X.500 server. DAP is a heavyweight protocol that operates over a
+full OSI protocol stack and requires a significant amount of
+computing resources. LDAP is designed to operate over
+{{TERM:TCP}}/{{TERM:IP}} and provides most of the functionality of
+DAP at a much lower cost.
+
+While LDAP is still used to access X.500 directory service via
+gateways, LDAP is now more commonly directly implemented in X.500
+servers.
+
+The stand-alone LDAP daemon, or {{slapd}}(8), can be viewed as a
+{{lightweight}} X.500 directory server. That is, it does not
+implement the X.500's DAP. As a {{lightweight directory}} server,
+{{slapd}}(8) implements only a subset of the X.500 models.
+
+If you are already running a X.500 DAP service and you want to
+continue to do so, you can probably stop reading this guide. This
+guide is all about running LDAP via {{slapd}}(8), without running
+X.500 DAP. If you are not running X.500 DAP, want to stop running
+X.500 DAP, or have no immediate plans to run X.500 DAP, read on.
+
+It is possible to replicate data from an LDAP directory server to
+a X.500 DAP {{TERM:DSA}}. This requires an LDAP/DAP gateway.
+OpenLDAP does not provide such a gateway, but our replication daemon
+can be used to replicate to such a gateway. See the {{SECT:Replication
+with slurpd}} chapter of this document for information regarding
+replication.
+
+
+H2: What the difference between LDAPv2 and LDAPv3?
+
+There are two versions of LDAP in use today on the Internet.
+LDAPv3 was developed in late 1990's to replace LDAPv2. LDAPv3
+adds the following features to LDAP:
+
+ - Strong Authentication via {{TERM:SASL}}
+ - Integrity and Confidential Protections via {{TERM:TLS}} (SSL)
+ - Internationalization through the use of Unicode
+ - Referrals and Continuations
+ - Extensibility (controls and extended operations)
+ - Schema Discovery
+
+Supporting both LDAPv2 and LDAPv3 simultaneously can be problematic
+and generally should be avoided. As LDAPv3 is more consistenly
+implemented and supports all the features of LDAPv2, use of LDAPv3
+is highly recommended.
H2: What is slapd and what can it do?
-{{slapd}} is an LDAP directory server that runs on many different
-platforms. You can use it to provide a directory service of your very own.
-Your directory can contain pretty much anything you want to put in it. You
-can connect it to the global LDAP directory service, or run a service all by
-yourself. Some of slapd's more interesting features and capabilities include:
-
-{{B:LDAPv2}} and {{B:LDAPv3}}: {{slapd}} supports both version 2 and 3
-of the {{TERM[expand]LDAP}}. {{slapd}} provides support
-for the latest features while maintaining interoperability with
-existing clients. {{slapd}} supports both IPv4 and IPv6.
-
-{{B:{{TERM[expand]SASL}}}}: {{slapd}} supports
-strong authentication services through the use of SASL. {{slapd}}'s
-SASL implementation utilizes {{PRD:Cyrus}} {{PRD:SASL}} software
-which supports a number of mechanisms including
-DIGEST-MD5, EXTERNAL, and GSSAPI.
-
-{{B:{{TERM[expand]TLS}}}}: {{slapd}} provides privacy and
-integrity protections through the use of TLS (or SSL). {{slapd}}'s
-TLS implementation utilizes {{PRD:OpenSSL}} software.
-
-{{B:Access control}}: {{slapd}} provides a rich and powerful access
-control facility, allowing you to control access to the information
-in your database(s). You can control access to entries based on
+{{slapd}}(8) is an LDAP directory server that runs on many different
+platforms. You can use it to provide a directory service of your
+very own. Your directory can contain pretty much anything you want
+to put in it. You can connect it to the global LDAP directory
+service, or run a service all by yourself. Some of slapd's more
+interesting features and capabilities include:
+
+{{B:LDAPv3}}: {{slapd}} implements version 3 of {{TERM[expand]LDAP}}.
+{{slapd}} supports LDAP over both IPv4 and IPv6.
+
+{{B:{{TERM[expand]SASL}}}}: {{slapd}} supports strong authentication
+services through the use of SASL. {{slapd}}'s SASL implementation
+utilizes {{PRD:Cyrus}} {{PRD:SASL}} software which supports a number
+of mechanisms including DIGEST-MD5, EXTERNAL, and GSSAPI.
+
+{{B:{{TERM[expand]TLS}}}}: {{slapd}} provides privacy and integrity
+protections through the use of TLS (or SSL). {{slapd}}'s TLS
+implementation utilizes {{PRD:OpenSSL}} software.
+
+{{B:Topology control}}: {{slapd}} allows one to restrict access to
+the server based upon network topology. This feature utilizes
+{{TCP wrappers}}.
+
+{{B:Access control}}: {{slapd}} provides a rich and powerful access
+control facility, allowing you to control access to the information
+in your database(s). You can control access to entries based on
LDAP authorization information, {{TERM:IP}} address, domain name
-and other criteria.
-{{slapd}} supports both {{static}} and {{dynamic}} access control
-information.
+and other criteria. {{slapd}} supports both {{static}} and
+{{dynamic}} access control information.
{{B:Internationalization}}: {{slapd}} supports Unicode and language
tags.
-{{B:Choice of databases}}: {{slapd}} comes with a variety of different
-backend databases you can choose from. They include
+{{B:Choice of databases}}: {{slapd}} comes with a variety of
+different backend databases you can choose from. They include
{{TERM:LDBM}}, a high-performance disk-based embedded database;
-SHELL, a database interface to arbitrary shell scripts; and
-PASSWD, a simple password file database. LDBM utilizes either
-{{PRD:BerkeleyDB}} or {{PRD:GDBM}}.
+SHELL, a database interface to arbitrary shell scripts; and PASSWD,
+a simple password file database. LDBM utilizes either {{PRD:BerkeleyDB}}
+or {{PRD:GDBM}}.
-{{B:Multiple database instances}}: {{slapd}} can be configured to serve
-multiple databases at the same time. This means that a single {{slapd}}
-server can respond to requests for many logically different portions
-of the LDAP tree, using the same or different backend databases.
+{{B:Multiple database instances}}: {{slapd}} can be configured to
+serve multiple databases at the same time. This means that a single
+{{slapd}} server can respond to requests for many logically different
+portions of the LDAP tree, using the same or different backend
+databases.
{{B:Generic modules API}}: If you require even more customization,
-{{slapd}} lets you write your own modules easily. {{slapd}}
-consists of two distinct parts: a front end that handles protocol
-communication with LDAP clients; and modules which handle specific
-tasks such as database operations. Because these two pieces communicate
-via a well-defined {{TERM:C}} {{TERM:API}}, you can write your own
-customized modules
-which extend {{slapd}} in numerous ways. Also, a number of
-{{programmable database}} modules are provided. These allow you
-to expose external data sources to {{slapd}} using popular programming
-languages ({{PRD:Perl}}, {{Shell}}, {{PRD:SQL}}, and {{PRD:TCL}}).
-
-{{B:Threads}}: {{slapd}} is threaded for high performance. A
-single multi-threaded {{slapd}} process handles all incoming
-requests, reducing the amount of system overhead required.
-
-{{B:Replication}}: {{slapd}} can be configured to maintain replica
+{{slapd}} lets you write your own modules easily. {{slapd}} consists
+of two distinct parts: a front end that handles protocol communication
+with LDAP clients; and modules which handle specific tasks such as
+database operations. Because these two pieces communicate via a
+well-defined {{TERM:C}} {{TERM:API}}, you can write your own
+customized modules which extend {{slapd}} in numerous ways. Also,
+a number of {{programmable database}} modules are provided. These
+allow you to expose external data sources to {{slapd}} using popular
+programming languages ({{PRD:Perl}}, {{Shell}}, {{PRD:SQL}}, and
+{{PRD:TCL}}).
+
+{{B:Threads}}: {{slapd}} is threaded for high performance. A single
+multi-threaded {{slapd}} process handles all incoming requests,
+reducing the amount of system overhead required.
+
+{{B:Replication}}: {{slapd}} can be configured to maintain replica
copies of its database. This {{single-master/multiple-slave}}
replication scheme is vital in high-volume environments where a
single {{slapd}} just doesn't provide the necessary availability
or reliability. {{slapd}} also includes experimental support for
{{multi-master}} replication.
-{{B:Configuration}}: {{slapd}} is highly configurable through a
-single configuration file which allows you to change just about
-everything you'd ever want to change. Configuration options have
+{{B:Configuration}}: {{slapd}} is highly configurable through a
+single configuration file which allows you to change just about
+everything you'd ever want to change. Configuration options have
reasonable defaults, making your job much easier.
-{{slapd}} also has its limitations, of course. The main LDBM
+{{slapd}} also has its limitations, of course. The main LDBM
database backend does not handle range queries or negation queries
-very well. These features and more will be coming in a future release.
-
-
-H2: What about X.500?
-
-Technically, LDAP is a directory access protocol to an {{TERM:X.500}}
-directory service, the {{TERM:OSI}} directory service. Initial
-LDAP servers were gateways between LDAP and the X.500 {{TERM[expand]DAP}}
-({{TERM:DAP}}). DAP is a heavyweight protocol that operates over a full
-OSI protocol stack and requires a significant amount of computing
-resources. LDAP is designed to operate over {{TERM:TCP}}/{{TERM:IP}}
-and provides most of the functionality of DAP at a much lower cost.
-
-This use of LDAP makes it easy to access the X.500 directory, but still
-requires a full X.500 service to make data available to the many LDAP
-clients being developed. As with full X.500 DAP clients, a full X.500
-DAP server is no small piece of software to operate.
-
-The stand-alone LDAP daemon, or {{slapd}}(8), is meant to remove much
-of the burden from the server side just as LDAP itself removed much of
-the burden from clients. If you are already running a X.500 DAP service
-and you want to continue to do so, you can probably stop reading this
-guide, which is all about running LDAP via {{slapd}}, without running
-X.500 DAP. If you are not running X.500 DAP, want to stop running
-X.500 DAP, or have no immediate plans to run X.500 DAP, read on.
-
-It is possible to replicate data from an LDAP directory
-server to a X.500 DAP {{TERM:DSA}}. This requires an LDAP/DAP
-gateway. OpenLDAP does not provide such a gateway, but our
-replication daemon can be used to replicate to such a gateway.
-See the {{SECT:Replication with slurpd}} chapter of this document
-for information regarding replication.
+very well. These features and more will be coming in a future
+release.
H2: What is slurpd and what can it do?
-{{slurpd}}(8) is a daemon that helps {{slapd}} provide
-replicated service. It is responsible for distributing changes made
-to the master {{slapd}} database out to the various {{slapd}}
-replicas. It frees {{slapd}} from having to worry that some
-replicas might be down or unreachable when a change comes through;
-{{slurpd}} handles retrying failed requests automatically.
-{{slapd}} and {{slurpd}} communicate through a simple text
-file that is used to log changes.
+{{slurpd}}(8) is a daemon that helps {{slapd}} provide replicated
+service. It is responsible for distributing changes made to the
+master {{slapd}} database out to the various {{slapd}} replicas.
+It frees {{slapd}} from having to worry that some replicas might
+be down or unreachable when a change comes through; {{slurpd}}
+handles retrying failed requests automatically. {{slapd}} and
+{{slurpd}} communicate through a simple text file that is used to
+log changes.
See the {{SECT:Replication with slurpd}} chapter for information
about how to configure and run {{slurpd}}(8).
H1: Using SASL
-This chapter details how to make use of SASL to provide authentication.
-OpenLDAP clients and servers are capable of providing authentication
-via the {{TERM[expand]SASL}} ({{TERM:SASL}}) system, which is
-explained in {{REF:RFC2222}}. There are several industry standard
-authentication mechanisms that can be used with SASL, including
-Kerberos V4, GSSAPI, and some of the Digest mechanisms. The standard
-client tools provided with OpenLDAP, such as {{ldapsearch}}(1) and
-{{ldapmodify}}(1), will by default attempt to authenticate the user
-to the {{slapd}}(8) server using SASL. Basic authentication service
-can be set up by the LDAP administrator with a few steps, allowing
-users to be authenticated to the slapd server as their LDAP entry.
-With a few extra steps, some users and services can be allowed to
-exploit SASL's authorization feature, allowing them to authenticate
-themselves and then switch their identity to that of another user
-or service.
+OpenLDAP clients and servers are capable of authenticating via the
+{{TERM[expand]SASL}} ({{TERM:SASL}}) framework, which is detailed
+in {{REF:RFC2222}}. This chapter describes how to make use of
+SASL in OpenLDAP.
+
+There are several industry standard authentication mechanisms that
+can be used with SASL, including Kerberos V4, GSSAPI, and some of
+the Digest mechanisms. The standard client tools provided with
+OpenLDAP, such as {{ldapsearch}}(1) and {{ldapmodify}}(1), will by
+default attempt to authenticate the user to the {{slapd}}(8) server
+using SASL. Basic authentication service can be set up by the LDAP
+administrator with a few steps, allowing users to be authenticated
+to the slapd server as their LDAP entry. With a few extra steps,
+some users and services can be allowed to exploit SASL's authorization
+feature, allowing them to authenticate themselves and then switch
+their identity to that of another user or service.
This chapter assumes you have read {{Cyrus SASL for System
Administrators}}, provided with the {{PRD:Cyrus}} {{PRD:SASL}}
is an application entity.
-H2: Security Considerations
+H2: SASL Security Considerations
SASL offers many different authentication mechanisms. This section
briefly outlines security considerations.
authorization DN ready to undergo approval.
If the authorization identity was provided in the second form, with
-a "dn:" prefix, the string after the prefix is already in authorization
-DN form, ready to undergo approval.
+a {EX:"dn:"}} prefix, the string after the prefix is already in
+authorization DN form, ready to undergo approval.
H3: Authorization rules
must be coming from in order to switch to that authorization DN.
The choice of which form to use is up to the administrator. Source
rules are checked first in the person's authentication DN entry,
-and if none of the saslAuthzTo rules specify the authorization is
-permitted, the saslAuthzFrom rules in the authorization DN entry
-are then checked. If neither case specifies that the request be
-honored, the request is denied with an "inappropriate access"
-message. Since the default behaviour is to deny authorization
+and if none of the {{EX:saslAuthzTo}} rules specify the authorization
+is permitted, the {{EX:saslAuthzFrom}} rules in the authorization
+DN entry are then checked. If neither case specifies that the
+request be honored, the request is denied with an "inappropriate
+access" message. Since the default behaviour is to deny authorization
requests, rules only specify that a request be allowed; there are
no negative rules telling what authorizations to deny.
output of the replacement pattern of a {{EX:saslRegexp}} directive:
either a DN or an LDAP URL. For example, if a saslAuthzTo value is
a DN, that DN is one the authenticated user can authorize to. On
-the other hand, if the saslAuthzTo value is an LDAP URL, the URL
-is used as an internal search of the LDAP database, and the
-authenticated user can become ANY DN returned by the search. If an
-LDAP entry looked like:
+the other hand, if the {{EX:saslAuthzTo}} value is an LDAP URL,
+the URL is used as an internal search of the LDAP database, and
+the authenticated user can become ANY DN returned by the search.
+If an LDAP entry looked like:
> dn: cn=WebUpdate,dc=example,dc=com
> saslAuthzTo: ldap://host/dc=example,dc=com??sub?objectclass=Person
H4: Notes on Authorization rules
-An LDAP URL in a saslAuthzTo or saslAuthzFrom attribute will return
-a list of DN's, and that list must be linearly scanned. Searches
-which return a long list can cause the authorization process to
-take an uncomfortably long time. Also, searches should be performed
-on attributes that have been indexed by slapd.
+An LDAP URL in a {{EX:saslAuthzTo}} or {{EX:saslAuthzFrom}} attribute
+will return a set of DNs. Each DN returned will be checked.
+Searches which return a large set can cause the authorization
+process to take an uncomfortably long time. Also, searches should
+be performed on attributes that have been indexed by slapd.
-To help produce more sweeping rules for saslAuthzFrom and saslAuthzTo,
-the values of these attributes are allowed to be DN's with regular
-expression characters in them. This means a source rule like
+To help produce more sweeping rules for {{EX:saslAuthzFrom}} and
+{{EX:saslAuthzTo}}, the values of these attributes are allowed to
+be DNs with regular expression characters in them. This means a
+source rule like
> saslAuthzTo: uid=.*,dc=example,dc=com
projects / openldap / commitdiff