draft-ietf-ldapbis-authmeth-17.txt   draft-ietf-ldapbis-authmeth-18.txt 
INTERNET-DRAFT Editor: R. Harrison INTERNET-DRAFT Editor: R. Harrison
draft-ietf-ldapbis-authmeth-17.txt Novell, Inc. draft-ietf-ldapbis-authmeth-18.txt Novell, Inc.
Obsoletes: 2829, 2830 October, 2005 Obsoletes: 2251, 2829, 2830 November, 2005
Intended Category: Standards Track Intended Category: Standards Track
LDAP: Authentication Methods LDAP: Authentication Methods
and and
Security Mechanisms Security Mechanisms
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
skipping to change at page 2, line 21 skipping to change at page 2, line 21
authentication method including the EXTERNAL mechanism. authentication method including the EXTERNAL mechanism.
This document discusses various authentication and authorization This document discusses various authentication and authorization
states through which a session to an LDAP server may pass and the states through which a session to an LDAP server may pass and the
actions that trigger these state changes. actions that trigger these state changes.
Table of Contents Table of Contents
1. Introduction.....................................................3 1. Introduction.....................................................3
1.1. Relationship to Other Documents................................5 1.1. Relationship to Other Documents................................5
1.2.Conventions.....................................................5 1.2. Conventions....................................................6
2. Implementation Requirements......................................6 2. Implementation Requirements......................................6
3. StartTLS Operation...............................................7 3. StartTLS Operation...............................................7
3.1. TLS Establishment Procedures...................................7 3.1. TLS Establishment Procedures...................................7
3.1.1. StartTLS Request Sequencing..................................7 3.1.1. StartTLS Request Sequencing..................................7
3.1.2. Client Certificate...........................................8 3.1.2. Client Certificate...........................................8
3.1.3. Server Identity Check........................................8 3.1.3. Server Identity Check........................................8
3.1.3.1. Comparison of DNS Names....................................9 3.1.3.1. Comparison of DNS Names....................................9
3.1.3.2. Comparison of IP Addresses................................10 3.1.3.2. Comparison of IP Addresses................................10
3.1.3.3. Comparison of other subjectName types.....................10 3.1.3.3. Comparison of other subjectName types.....................10
3.1.4. Discovery of Resultant Security Level.......................10 3.1.4. Discovery of Resultant Security Level.......................10
3.1.5. Refresh of Server Capabilities Information..................10 3.1.5. Refresh of Server Capabilities Information..................11
3.2. Effect of TLS on Authorization State..........................11 3.2. Effect of TLS on Authorization State..........................11
3.3. TLS Ciphersuites..............................................11 3.3. TLS Ciphersuites..............................................11
4. Authorization State.............................................11 4. Authorization State.............................................12
5. Bind Operation..................................................12 5. Bind Operation..................................................13
5.1. Simple Authentication Method..................................13 5.1. Simple Authentication Method..................................13
5.1.1. Anonymous Authentication Mechanism of Simple Bind...........13 5.1.1. Anonymous Authentication Mechanism of Simple Bind...........13
5.1.2. Unauthenticated Authentication Mechanism of Simple Bind.....13 5.1.2. Unauthenticated Authentication Mechanism of Simple Bind.....13
5.1.3. Name/Password Authentication Mechanism of Simple Bind ......13 5.1.3. Name/Password Authentication Mechanism of Simple Bind.......14
5.2. SASL Authentication Method....................................14 5.2. SASL Authentication Method....................................15
5.2.1. SASL Protocol Profile.......................................14 5.2.1. SASL Protocol Profile.......................................15
5.2.1.1. SASL Service Name for LDAP................................14 5.2.1.1. SASL Service Name for LDAP................................15
5.2.1.2. SASL Authentication Initiation and Protocol Exchange......14 5.2.1.2. SASL Authentication Initiation and Protocol Exchange......15
5.2.1.3. Octet Where Negotiated Security Layers Take Effect........16 5.2.1.3. Optional Fields...........................................16
5.2.1.4. Determination of Supported SASL Mechanisms................16 5.2.1.4. Octet Where Negotiated Security Layers Take Effect........17
5.2.1.5. Rules for Using SASL Layers...............................16 5.2.1.5. Determination of Supported SASL Mechanisms................17
5.2.1.6. Support for Multiple Authentications......................16 5.2.1.6. Rules for Using SASL Layers...............................17
5.2.1.7 SASL Authorization Identities..............................16 5.2.1.7. Support for Multiple Authentications......................18
5.2.2. SASL Semantics Within LDAP..................................17 5.2.1.8. SASL Authorization Identities.............................18
5.2.3. SASL EXTERNAL Authentication Mechanism......................18 5.2.2. SASL Semantics Within LDAP..................................19
5.2.3.1. Implicit Assertion........................................18 5.2.3. SASL EXTERNAL Authentication Mechanism......................19
5.2.3.2. Explicit Assertion........................................18 5.2.3.1. Implicit Assertion........................................19
6. Security Considerations.........................................19 5.2.3.2. Explicit Assertion........................................20
6.1. General LDAP Security Considerations..........................19 6. Security Considerations.........................................20
6.2. StartTLS Security Considerations..............................19 6.1. General LDAP Security Considerations..........................20
6.3. Bind Operation Security Considerations........................20 6.2. StartTLS Security Considerations..............................20
6.3.1. Unauthenticated Mechanism Security Considerations...........20 6.3. Bind Operation Security Considerations........................21
6.3.2. Name/Password Mechanism Security Considerations.............20 6.3.1. Unauthenticated Mechanism Security Considerations...........21
6.3.3. Password-related Security Considerations....................20 6.3.2. Name/Password Mechanism Security Considerations.............21
6.3.4. Hashed Password Security Considerations.....................21 6.3.3. Password-related Security Considerations....................22
6.4. Related Security Considerations...............................21 6.3.4. Hashed Password Security Considerations.....................23
7. IANA Considerations.............................................22 6.4. Related Security Considerations...............................23
8. Acknowledgments.................................................22 7. IANA Considerations.............................................23
9. Normative References............................................22 8. Acknowledgments.................................................23
10. Informative References.........................................23 9. Normative References............................................23
Author's Address...................................................24 10. Informative References.........................................25
Appendix A. Authentication and Authorization Concepts..............24 Author's Address...................................................25
A.1. Access Control Policy.........................................24 Appendix A. Authentication and Authorization Concepts..............25
A.2. Access Control Factors........................................24 A.1. Access Control Policy.........................................26
A.3. Authentication, Credentials, Identity.........................25 A.2. Access Control Factors........................................26
A.4. Authorization Identity........................................25 A.3. Authentication, Credentials, Identity.........................26
Appendix B. Summary of Changes.....................................25 A.4. Authorization Identity........................................26
B.1. Changes made to RFC 2829......................................26 Appendix B. Summary of Changes.....................................27
B.1.1. Section 4 (Required security mechanisms)....................26 B.1. Changes Made to RFC 2251......................................27
B.1.2. Section 5.1 (Anonymous authentication procedure)............26 B.1.1. Section 4.2.1 (Sequencing of the Bind Request)..............27
B.1.3. Section 6 (Password-based authentication)...................26 B.1.2. Section 4.2.2 (Authentication and Other Security Services)..28
B.1.4. Section 6.1 (Digest authentication).........................26 B.2. Changes Made to RFC 2829......................................28
B.1.5. Section 6.2 ("simple" authentication choice with TLS).......26 B.2.1. Section 4 (Required security mechanisms)....................28
B.1.6. Section 6.3 (Other authentication choices with TLS).........27 B.2.2. Section 5.1 (Anonymous authentication procedure)............28
B.1.7. Section 7.1 (Certificate-based authentication with TLS).....27 B.2.3. Section 6 (Password-based authentication)...................28
B.1.8. Section 8 (Other mechanisms)................................27 B.2.4. Section 6.1 (Digest authentication).........................28
B.1.8. Section 9 (Authorization identity)..........................27 B.2.5. Section 6.2 ("simple" authentication choice with TLS).......29
B.1.10. Section 10 (TLS Ciphersuites)..............................27 B.2.6. Section 6.3 (Other authentication choices with TLS).........29
B.2. Changes made to RFC 2830: ....................................27 B.2.7. Section 7.1 (Certificate-based authentication with TLS).....29
B.2.1. Section 3.6 (Server Identity Check).........................28 B.2.8. Section 8 (Other mechanisms)................................29
B.2.2. Section 3.7 (Refresh of Server Capabilities Information)....28 B.2.9. Section 9 (Authorization identity)..........................29
B.2.3. Section 5.2 (Effects of TLS on Authorization Identity)......28 B.2.10. Section 10 (TLS Ciphersuites)..............................29
B.2.4. Section 5.1.1 (TLS Closure Effects).........................28 B.3. Changes Made to RFC 2830: ....................................30
Appendix C. Changes for draft-ldapbis-authmeth-17..................28 B.3.1. Section 3.6 (Server Identity Check).........................30
Intellectual Property Rights.......................................29 B.3.2. Section 3.7 (Refresh of Server Capabilities Information)....30
Full Copyright Statement...........................................29 B.3.3. Section 5.2 (Effects of TLS on Authorization Identity)......30
B.3.4. Section 5.1.1 (TLS Closure Effects).........................30
Appendix C. Changes for draft-ldapbis-authmeth-18..................30
Intellectual Property Rights.......................................31
Full Copyright Statement...........................................32
1. Introduction 1. Introduction
The Lightweight Directory Access Protocol (LDAP) [Roadmap] is a The Lightweight Directory Access Protocol (LDAP) [Roadmap] is a
powerful protocol for accessing directories. It offers means of powerful protocol for accessing directories. It offers means of
searching, retrieving and manipulating directory content, and ways searching, retrieving and manipulating directory content and ways to
to access a rich set of security functions. access a rich set of security functions.
It is vital that these security functions be interoperable among all It is vital that these security functions be interoperable among all
LDAP clients and servers on the Internet; therefore there has to be LDAP clients and servers on the Internet; therefore there has to be
a minimum subset of security functions that is common to all a minimum subset of security functions that is common to all
implementations that claim LDAP conformance. implementations that claim LDAP conformance.
Basic threats to an LDAP directory service include (but are not Basic threats to an LDAP directory service include (but are not
limited to): limited to):
(1) Unauthorized access to directory data via data-retrieval (1) Unauthorized access to directory data via data-retrieval
skipping to change at page 5, line 22 skipping to change at page 5, line 25
mechanisms. mechanisms.
LDAP may also be protected by means outside the LDAP protocol, e.g. LDAP may also be protected by means outside the LDAP protocol, e.g.
with IP-level security [RFC2401]. with IP-level security [RFC2401].
Experience has shown that simply allowing implementations to pick Experience has shown that simply allowing implementations to pick
and choose the security mechanisms that will be implemented is not a and choose the security mechanisms that will be implemented is not a
strategy that leads to interoperability. In the absence of strategy that leads to interoperability. In the absence of
mandates, clients will continue to be written that do not support mandates, clients will continue to be written that do not support
any security function supported by the server, or worse, they will any security function supported by the server, or worse, they will
support only clear text passwords that provide inadequate security only support mechanisms that provide inadequate security for most
for most circumstances. circumstances.
It is desirable to allow clients to authenticate using a variety of It is desirable to allow clients to authenticate using a variety of
mechanisms including mechanisms where identities are represented as mechanisms including mechanisms where identities are represented as
distinguished names [X.501][Models] in string form [LDAPDN] or as distinguished names [X.501][Models] in string form [LDAPDN] or as
used in different systems (e.g. user name in string form). Because used in different systems (e.g. simple user names [RFC4013]).
some authentication mechanisms transmit credentials in plain text Because some authentication mechanisms transmit credentials in plain
form, and/or do not provide data security services and/or are text form, and/or do not provide data security services and/or are
subject to passive attacks, it is necessary to ensure secure subject to passive attacks, it is necessary to ensure secure
interoperability by identifying a mandatory-to-implement mechanism interoperability by identifying a mandatory-to-implement mechanism
for establishing transport-layer security services. for establishing transport-layer security services.
The set of security mechanisms provided in LDAP and described in The set of security mechanisms provided in LDAP and described in
this document is intended to meet the security needs for a wide this document is intended to meet the security needs for a wide
range of deployment scenarios and still provide a high degree of range of deployment scenarios and still provide a high degree of
interoperability among various LDAP implementations and deployments. interoperability among various LDAP implementations and deployments.
1.1. Relationship to Other Documents 1.1. Relationship to Other Documents
This document is an integral part of the LDAP Technical This document is an integral part of the LDAP Technical
Specification [Roadmap]. Specification [Roadmap].
This document obsoletes RFC 2829. This document, together with [Roadmap], [Protocol], and [Models],
obsoletes RFC 2251 in its entirety. Sections 4.2.1 (portions), and
4.2.2 of RFC 2251 are obsoleted by this document. Appendix B.1
summarizes the substantive changes made to RFC 2251 by this document.
This document obsoletes RFC 2829 in its entirety. Appendix B.2
summarizes the substantive changes made to RFC 2829 by this document.
Sections 2 and 4 of RFC 2830 are obsoleted by [Protocol]. The Sections 2 and 4 of RFC 2830 are obsoleted by [Protocol]. The
remainder of RFC 2830 is obsoleted by this document. remainder of RFC 2830 is obsoleted by this document. Appendix B.3
summarizes the substantive changes made to RFC 2830 by this document.
1.2.Conventions 1.2.Conventions
The key words "MUST", "MUST NOT", "SHALL", "SHOULD", "SHOULD NOT", The key words "MUST", "MUST NOT", "SHALL", "SHOULD", "SHOULD NOT",
"MAY", and "OPTIONAL" in this document are to be interpreted as "MAY", and "OPTIONAL" in this document are to be interpreted as
described in RFC 2119 [RFC2119]. described in RFC 2119 [RFC2119].
The term "user" represents any human or application entity which is The term "user" represents any human or application entity which is
accessing the directory using a directory client. A directory accessing the directory using a directory client. A directory
client (or client) is also known as a directory user agent (DUA). client (or client) is also known as a directory user agent (DUA).
skipping to change at page 6, line 45 skipping to change at page 7, line 10
2. Implementation Requirements 2. Implementation Requirements
LDAP server implementations MUST support the anonymous LDAP server implementations MUST support the anonymous
authentication mechanism of the simple Bind method (section 5.1.1). authentication mechanism of the simple Bind method (section 5.1.1).
LDAP implementations that support any authentication mechanism other LDAP implementations that support any authentication mechanism other
than the anonymous authentication mechanism of the simple Bind than the anonymous authentication mechanism of the simple Bind
method MUST support the name/password authentication mechanism of method MUST support the name/password authentication mechanism of
the simple Bind method (section 5.1.3) and MUST be capable of the simple Bind method (section 5.1.3) and MUST be capable of
protecting this name/password authentication using TLS as protecting this name/password authentication using TLS as
established by the StartTLS operation (section 3). Implementations established by the StartTLS operation (section 3).
SHOULD disallow the use of name/password authentication by default
when suitable data security are not in place.
Implementations SHOULD disallow the use of the name/password Implementations SHOULD disallow the use of the name/password
authentication mechanism by default when suitable data security authentication mechanism by default when suitable data security
services are not in place, and MAY provide other suitable data services are not in place, and MAY provide other suitable data
security services for use with this authentication mechanism. security services for use with this authentication mechanism.
Implementations MAY support additional authentication mechanisms. Implementations MAY support additional authentication mechanisms.
Some of these mechanisms are discussed below. Some of these mechanisms are discussed below.
LDAP server implementations SHOULD support client assertion of LDAP server implementations SHOULD support client assertion of
authorization identity via the SASL EXTERNAL mechanism (sections authorization identity via the SASL EXTERNAL mechanism (section
3.2.2 and 5.2.1). 5.2.3).
LDAP server implementations that support no authentication mechanism LDAP server implementations that support no authentication mechanism
other than the anonymous mechanism of the simple bind method SHOULD other than the anonymous mechanism of the simple bind method SHOULD
support use of TLS as established by the the StartTLS operation support use of TLS as established by the the StartTLS operation
(section 3). (Other servers MUST support TLS per the second (section 3). (Other servers MUST support TLS per the second
paragraph of this section.) paragraph of this section.)
Implementations supporting TLS MUST support the Implementations supporting TLS MUST support the
TLS_DHE_DSS_WITH_3DES_EBE_CBC_SHA ciphersuite. TLS_DHE_DSS_WITH_3DES_EBE_CBC_SHA ciphersuite.
skipping to change at page 8, line 10 skipping to change at page 8, line 22
As described in [Protocol] Section 4.14.1, a (detected) violation of As described in [Protocol] Section 4.14.1, a (detected) violation of
any of these requirements results in a return of the operationsError any of these requirements results in a return of the operationsError
resultCode. resultCode.
Client implementers should ensure that they strictly follow these Client implementers should ensure that they strictly follow these
operation sequencing requirements to prevent interoperability operation sequencing requirements to prevent interoperability
issues. Operational experience has shown that violating these issues. Operational experience has shown that violating these
requirements causes interoperability issues because there are race requirements causes interoperability issues because there are race
conditions that prevent servers from detecting some violations of conditions that prevent servers from detecting some violations of
these requirements due to server hardware speed, network latencies, these requirements due to factors such as server hardware speed and
etc.. network latencies.
There is no general requirement that the client have or have not There is no general requirement that the client have or have not
already performed a Bind operation (section 4) before sending a already performed a Bind operation (section 5) before sending a
StartTLS operation request, however where a client intends to StartTLS operation request, however where a client intends to
perform both a Bind operation and a StartTLS operation, it SHOULD perform both a Bind operation and a StartTLS operation, it SHOULD
first perform the StartTLS operation so that the Bind request and first perform the StartTLS operation so that the Bind request and
response messages are protected by the data security services response messages are protected by the data security services
established by the StartTLS operation. established by the StartTLS operation.
3.1.2. Client Certificate 3.1.2. Client Certificate
If an LDAP server requests or demands that a client provide a user If an LDAP server requests or demands that a client provide a user
certificate during TLS negotiation and the client does not present a certificate during TLS negotiation and the client does not present a
suitable user certificate (e.g. one that can be validated), the suitable user certificate (e.g. one that can be validated), the
server may use a local security policy to determine whether to server may use a local security policy to determine whether to
successfully complete TLS negotiation. successfully complete TLS negotiation.
If a client that has provided a suitable certificate subsequently If a client that has provided a suitable certificate subsequently
performs a Bind operation using the SASL EXTERNAL authentication performs a Bind operation using the SASL EXTERNAL authentication
mechanism (section 5.2.1), information in the certificate may be mechanism (section 5.2.3), information in the certificate may be
used by the server to identify and authenticate the client. used by the server to identify and authenticate the client.
3.1.3. Server Identity Check 3.1.3. Server Identity Check
In order to prevent man-in-the-middle attacks the client MUST verify In order to prevent man-in-the-middle attacks the client MUST verify
the server's identity (as presented in the server's Certificate the server's identity (as presented in the server's Certificate
message). In this section, the client's understanding of the message). In this section, the client's understanding of the
server's identity (typically the identity used to establish the server's identity (typically the identity used to establish the
transport connection) is called the "reference identity". transport connection) is called the "reference identity".
The client determines the type (e.g. DNS name or IP address) of the The client determines the type (e.g. DNS name or IP address) of the
reference identity and performs a comparison between the reference reference identity and performs a comparison between the reference
identity and each subjectAltName value of the corresponding type identity and each subjectAltName value of the corresponding type
until a match is produced. Once a match is produced, the server's until a match is produced. Once a match is produced, the server's
identity has been verified and the server identity check is identity has been verified and the server identity check is
complete. Different subjectAltName types are matched in different complete. Different subjectAltName types are matched in different
ways. Sections 3.1.3.1-3.1.3.3 explain how to compare various types ways. Sections 3.1.3.1 - 3.1.3.3 explain how to compare values of
of subjectAltName. various subjectAltName types.
The client may map the reference identity to a different type prior The client may map the reference identity to a different type prior
to performing a comparison. Mappings may be performed for all to performing a comparison. Mappings may be performed for all
available subjectAltName types to which the reference identity can available subjectAltName types to which the reference identity can
be mapped, however the reference identity should only be mapped to be mapped, however the reference identity should only be mapped to
types for which the mapping is either inherently secure (e.g. types for which the mapping is either inherently secure (e.g.
extracting the DNS name from a URI to compare with a subjectAltName extracting the DNS name from a URI to compare with a subjectAltName
of type dNSName) or for which the mapping is performed in a secure of type dNSName) or for which the mapping is performed in a secure
manner that is not subject to attack (e.g. using DNSSec, or using manner (e.g. using DNSSec, or using user- (or admin-) configured
user- (or admin-) configured host-to-address/address-to-host lookup host-to-address/address-to-host lookup tables).
tables).
The server's identity may also be verified by comparing the The server's identity may also be verified by comparing the
reference identity to the Common Name value in the leaf RDN of the reference identity to the Common Name (CN) [Schema] value in the
subjectName field of the server's certificate. This comparison is leaf RDN of the subjectName field of the server's certificate. This
performed using the rules for comparison of DNS names in section comparison is performed using the rules for comparison of DNS names
3.1.3.1 below, with the exception that no wildcard matching is in section 3.1.3.1 below, with the exception that no wildcard
allowed. Although the use of the Common Name value is existing matching is allowed. Although the use of the Common Name value is
practice, it is deprecated and Certification Authorities are existing practice, it is deprecated and Certification Authorities
encouraged to provide subjectAltName values instead. Note that the are encouraged to provide subjectAltName values instead. Note that
TLS implementation may display DNs in certificates according to the TLS implementation may represent DNs in certificates according
X.509 conventions. For example, some X.500 implementations order to X.500 or other conventions. For example, some X.500
the RDNs in a DN using a left-to-right (most significant to least implementations order the RDNs in a DN using a left-to-right (most
significant) convention instead of LDAP's right-to-left convention. significant to least significant) convention instead of LDAP's
right-to-left convention.
If the server identity check fails, user-oriented clients SHOULD If the server identity check fails, user-oriented clients SHOULD
either notify the user (clients may give the user the opportunity to either notify the user (clients may give the user the opportunity to
continue with the LDAP session in this case) or close the transport continue with the LDAP session in this case) or close the transport
connection and indicate that the server's identity is suspect. connection and indicate that the server's identity is suspect.
Automated clients SHOULD close the transport connection and then Automated clients SHOULD close the transport connection and then
return and/or log an error indicating that the server's identity is return or log an error indicating that the server's identity is
suspect. suspect or both.
Beyond the server identity check described in this section, clients Beyond the server identity check described in this section, clients
SHOULD be prepared to do further checking to ensure that the server should be prepared to do further checking to ensure that the server
is authorized to provide the service it is requested to provide. is authorized to provide the service it is requested to provide.
The client may need to make use of local policy information in The client may need to make use of local policy information in
making this determination. making this determination.
3.1.3.1. Comparison of DNS Names 3.1.3.1. Comparison of DNS Names
If the reference identity is an internationalized domain name, If the reference identity is an internationalized domain name,
conforming implementations MUST convert it to the ASCII Compatible conforming implementations MUST convert it to the ASCII Compatible
Encoding (ACE) format as specified in section 4 of RFC 3490 Encoding (ACE) format as specified in section 4 of RFC 3490
[RFC3490] before comparison with subjectAltName values of type [RFC3490] before comparison with subjectAltName values of type
dNSName. Specifically, conforming implementations MUST perform the dNSName. Specifically, conforming implementations MUST perform the
conversion operation specified in section 4 of RFC 3490 as follows: conversion operation specified in section 4 of RFC 3490 as follows:
* in step 1, the domain name SHALL be considered a "stored * in step 1, the domain name SHALL be considered a "stored
string"; string";
* in step 3, set the flag called "UseSTD3ASCIIRules"; * in step 3, set the flag called "UseSTD3ASCIIRules";
skipping to change at page 10, line 14 skipping to change at page 10, line 28
After performing the "to-ASCII" conversion, the DNS labels and names After performing the "to-ASCII" conversion, the DNS labels and names
MUST be compared for equality according to the rules specified in MUST be compared for equality according to the rules specified in
section 3 of RFC3490. section 3 of RFC3490.
The '*' (ASCII 42) wildcard character is allowed in subjectAltName The '*' (ASCII 42) wildcard character is allowed in subjectAltName
values of type dNSName and then only as the left-most (least values of type dNSName and then only as the left-most (least
significant) DNS label in that value. This wildcard matches any significant) DNS label in that value. This wildcard matches any
left-most DNS label in the server name. That is, the subject left-most DNS label in the server name. That is, the subject
*.example.com matches the server names a.example.com and *.example.com matches the server names a.example.com and
b.example.com but not the server name example.com. b.example.com but does not match example.com or a.b.example.com.
3.1.3.2. Comparison of IP Addresses 3.1.3.2. Comparison of IP Addresses
When the reference identity is an IP address, the identity MUST be When the reference identity is an IP address, the identity MUST be
converted to the "network byte order" octet string representation converted to the "network byte order" octet string representation
[RFC791][RFC2460]. For IP Version 4, as specified in RFC 791, the [RFC791][RFC2460]. For IP Version 4, as specified in RFC 791, the
octet string will contain exactly four octets. For IP Version 6, as octet string will contain exactly four octets. For IP Version 6, as
specified in RFC 2460, the octet string will contain exactly sixteen specified in RFC 2460, the octet string will contain exactly sixteen
octets. This octet string is then compared against subjectAltName octets. This octet string is then compared against subjectAltName
values of type iPAddress. A match occurs if the reference identity values of type iPAddress. A match occurs if the reference identity
octet string and value octet strings are identical. octet string and value octet strings are identical.
3.1.3.3. Comparison of other subjectName types 3.1.3.3. Comparison of other subjectName types
Client implementations may support matching against subjectAltName Client implementations MAY support matching against subjectAltName
values of other types as described in other documents. values of other types as described in other documents.
3.1.4. Discovery of Resultant Security Level 3.1.4. Discovery of Resultant Security Level
After a TLS layer is established in an LDAP session, both parties After a TLS layer is established in an LDAP session, both parties
are to each independently decide whether or not to continue based on are to each independently decide whether or not to continue based on
local policy and the security level achieved. If either party local policy and the security level achieved. If either party
decides that the security level is inadequate for it to continue, it decides that the security level is inadequate for it to continue, it
SHOULD remove the TLS layer immediately after the TLS SHOULD remove the TLS layer immediately after the TLS
(re)negotiation has completed (see [Protocol] section 4.14.3 and (re)negotiation has completed (see [Protocol] section 4.14.3 and
section 3.2 below). Implementations may reevaluate the security section 3.2 below). Implementations may reevaluate the security
level at any time and, upon finding it inadequate, should remove the level at any time and, upon finding it inadequate, should remove the
TLS layer. TLS layer.
skipping to change at page 10, line 54 skipping to change at page 11, line 24
3.1.5. Refresh of Server Capabilities Information 3.1.5. Refresh of Server Capabilities Information
After a TLS layer is established in an LDAP session, the client After a TLS layer is established in an LDAP session, the client
SHOULD discard or refresh all information about the server it SHOULD discard or refresh all information about the server it
obtained prior to the initiation of the TLS negotiation and not obtained prior to the initiation of the TLS negotiation and not
obtained through secure mechanisms. This protects against man-in- obtained through secure mechanisms. This protects against man-in-
the-middle attacks that may have altered any server capabilities the-middle attacks that may have altered any server capabilities
information retrieved prior to TLS layer installation. information retrieved prior to TLS layer installation.
The server may advertise different capabilities after installing a The server may advertise different capabilities after installing a
TLS layer. In particular, the value of supportedSASLMechanisms may TLS layer. In particular, the value of 'supportedSASLMechanisms'
be different after a TLS layer has been installed (specifically, the may be different after a TLS layer has been installed (specifically,
EXTERNAL and PLAIN [PLAIN] mechanisms are likely to be listed only the EXTERNAL and PLAIN [PLAIN] mechanisms are likely to be listed
after a TLS layer has been installed). only after a TLS layer has been installed).
3.2. Effect of TLS on Authorization State 3.2. Effect of TLS on Authorization State
The establishment, change, and/or closure of TLS may cause the The establishment, change, and/or closure of TLS may cause the
authorization state to move to a new state. This is discussed authorization state to move to a new state. This is discussed
further in Section 4. further in Section 4.
3.3. TLS Ciphersuites 3.3. TLS Ciphersuites
Several issues should be considered when selecting TLS ciphersuites Several issues should be considered when selecting TLS ciphersuites
skipping to change at page 11, line 48 skipping to change at page 12, line 21
- After a TLS negotiation (either initial or subsequent) is - After a TLS negotiation (either initial or subsequent) is
completed, both protocol peers should independently verify that completed, both protocol peers should independently verify that
the security services provided by the negotiated ciphersuite are the security services provided by the negotiated ciphersuite are
adequate for the intended use of the LDAP session. If not, the adequate for the intended use of the LDAP session. If not, the
TLS layer should be closed. TLS layer should be closed.
4. Authorization State 4. Authorization State
Every LDAP session has an associated authorization state. This Every LDAP session has an associated authorization state. This
state is comprised of numerous factors such as what (if any) state is comprised of numerous factors such as what (if any)
authorization identity has been established, how it was established, authorization state has been established, how it was established,
and what security services are in place. Some factors may be and what security services are in place. Some factors may be
determined and/or affected by protocol events (e.g., Bind, StartTLS, determined and/or affected by protocol events (e.g. Bind, StartTLS,
or TLS closure), and some factors may be determined by external or TLS closure), and some factors may be determined by external
events (e.g., time of day or server load). events (e.g. time of day or server load).
While it is often convenient to view authorization state in While it is often convenient to view authorization state in
simplistic terms (as we often do in this technical specification) simplistic terms (as we often do in this technical specification)
such as "an anonymous state", it is noted that authorization systems such as "an anonymous state", it is noted that authorization systems
in LDAP implementations commonly involve many factors which in LDAP implementations commonly involve many factors which
interrelate in complex manners. interrelate in complex manners.
Authorization in LDAP is a local matter. One of the key factors in Authorization in LDAP is a local matter. One of the key factors in
making authorization decisions is authorization identity. The Bind making authorization decisions is authorization identity. The Bind
operation defined in section 4.2 of [Protocol] and discussed further operation defined in section 4.2 of [Protocol] and discussed further
skipping to change at page 12, line 30 skipping to change at page 12, line 52
anonymous authorization identity. Among other things this implies anonymous authorization identity. Among other things this implies
that the client need not send a BindRequest in the first PDU of the that the client need not send a BindRequest in the first PDU of the
LDAP message layer. The client may send any operation request prior LDAP message layer. The client may send any operation request prior
to performing a Bind operation, and the server MUST treat it as if to performing a Bind operation, and the server MUST treat it as if
it had been performed after an anonymous Bind operation (section it had been performed after an anonymous Bind operation (section
5.1.1). 5.1.1).
Upon receipt of a Bind request, the server immediately moves the Upon receipt of a Bind request, the server immediately moves the
session to an anonymous authorization state. If the Bind request is session to an anonymous authorization state. If the Bind request is
successful, the session is moved to the requested authentication successful, the session is moved to the requested authentication
state with its associated authorization state and identity. state with its associated authorization state. Otherwise, the
Otherwise, the session remains in an anonymous state. session remains in an anonymous state.
It is noted that other events both internal and external to LDAP may It is noted that other events both internal and external to LDAP may
result in the authentication and authorization states being moved to result in the authentication and authorization states being moved to
an anonymous one. For instance, the establishment, change, or an anonymous one. For instance, the establishment, change or
closure of security services may result in a move to an anonymous closure of data security services may result in a move to an
state, or the user's credential information (e.g., certificate) may anonymous state, or the user's credential information (e.g.
have expired. The former is an example of an event internal to LDAP certificate) may have expired. The former is an example of an event
whereas the latter is an example of an event external to LDAP. internal to LDAP whereas the latter is an example of an event
external to LDAP.
5. Bind Operation 5. Bind Operation
The Bind operation ([Protocol] section 4.2) allows authentication The Bind operation ([Protocol] section 4.2) allows authentication
information to be exchanged between the client and server to information to be exchanged between the client and server to
establish a new authorization state. establish a new authorization state.
The Bind request typically specifies the desired authentication The Bind request typically specifies the desired authentication
identity. Some Bind mechanisms also allow the client to specify the identity. Some Bind mechanisms also allow the client to specify the
authorization identity. If the authorization identity is not authorization identity. If the authorization identity is not
skipping to change at page 13, line 27 skipping to change at page 14, line 4
5.1.1. Anonymous Authentication Mechanism of Simple Bind 5.1.1. Anonymous Authentication Mechanism of Simple Bind
An LDAP client may use the anonymous authentication mechanism of the An LDAP client may use the anonymous authentication mechanism of the
simple Bind method to explicitly establish an anonymous simple Bind method to explicitly establish an anonymous
authorization state by sending a Bind request with a name value of authorization state by sending a Bind request with a name value of
zero length and specifying the simple authentication choice zero length and specifying the simple authentication choice
containing a password value of zero length. containing a password value of zero length.
5.1.2. Unauthenticated Authentication Mechanism of Simple Bind 5.1.2. Unauthenticated Authentication Mechanism of Simple Bind
An LDAP client may use the unauthenticated authentication mechanism An LDAP client may use the unauthenticated authentication mechanism
of the simple Bind method to establish an anonymous authorization of the simple Bind method to establish an anonymous authorization
state by sending a Bind request with a name value (a distinguished state by sending a Bind request with a name value (a distinguished
name in LDAP string form [LDAPDN] of non-zero length) and specifying name in LDAP string form [LDAPDN] of non-zero length) and specifying
the simple authentication choice containing a password value of zero the simple authentication choice containing a password value of zero
length. length.
The distinguished name value provided by the client is not used to The distinguished name value provided by the client is intended to
establish the authentication identity, but it may be used by the be used for trace (e.g. logging) purposes only. The value is not to
server for other purposes such as tracing. Because no be authenticated or otherwise validated (including verification that
authentication of the distinguished name value is performed in this the DN refers to an existing directory object). The value is not be
mechanism, it is non-authoritative, and it should be used in a used (directly or indirectly) for authorization purposes.
manner consistent with this status.
Unauthenticated Bind operations can have significant security issues Unauthenticated Bind operations can have significant security issues
(see section 6.3). Servers SHOULD by default reject unauthenticated (see section 6.3.1). In particular, users intending to perform
Bind requests with a resultCode of invalidCredentials, and clients Name/Password Authentication may inadvertently provide an empty
may need to actively detect situations where they would password and thus cause poorly implemented clients to request
unintentionally make an unauthenticated Bind request. Unauthenticated access. Clients SHOULD be implemented to require
user selection of the Unauthenticated Authentication Mechanism by
means other than user input of an empty password. Clients SHOULD
disallow an empty password input to a Name/Password Authentication
user interface. Additionally, Servers SHOULD by default fail
Unauthenticated Bind requests with a resultCode of
unwillingToPerform.
5.1.3. Name/Password Authentication Mechanism of Simple Bind 5.1.3. Name/Password Authentication Mechanism of Simple Bind
An LDAP client may use the name/password authentication mechanism of An LDAP client may use the name/password authentication mechanism of
the simple Bind method to establish an authenticated authorization the simple Bind method to establish an authenticated authorization
state by sending a Bind request with a name value (a distinguished state by sending a Bind request with a name value (a distinguished
name in LDAP string form [LDAPDN] of non-zero length) and specifying name in LDAP string form [LDAPDN] of non-zero length) and specifying
the simple authentication choice containing an OCTET STRING password the simple authentication choice containing an OCTET STRING password
value of non-zero length. value of non-zero length.
Servers that map the DN sent in the Bind request to a directory Servers that map the DN sent in the Bind request to a directory
entry with an associated set of one or more passwords used with this entry with an associated set of one or more passwords used with this
mechanism will compare the presented password to that set of mechanism will compare the presented password to that set of
passwords. The presented password is considered valid if it matches passwords. The presented password is considered valid if it matches
any member of this set. any member of this set.
A resultCode of invalidDNSyntax indicates that the DN sent in the A resultCode of invalidDNSyntax indicates that the DN sent in the
name value is syntactically invalid. A resultCode of name value is syntactically invalid. A resultCode of
invalidCredentials indicates that the DN is syntactically correct invalidCredentials indicates that the DN is syntactically correct
but not valid for purposes of authentication, or the password is not but not valid for purposes of authentication, or the password is not
valid for the DN, or the server otherwise considers the credentials valid for the DN or the server otherwise considers the credentials
to be invalid. A resultCode of success indicates that the to be invalid. A resultCode of success indicates that the
credentials are valid and the server is willing to provide service credentials are valid and the server is willing to provide service
to the entity these credentials identify. to the entity these credentials identify.
Server behavior is undefined for Bind requests specifying the Server behavior is undefined for Bind requests specifying the
name/password authentication mechanism with a zero-length name value name/password authentication mechanism with a zero-length name value
and a password value of non-zero length. and a password value of non-zero length.
The name/password authentication mechanism of the simple Bind method The name/password authentication mechanism of the simple Bind method
is not suitable for authentication in environments without is not suitable for authentication in environments without
skipping to change at page 14, line 43 skipping to change at page 15, line 24
5.2.1. SASL Protocol Profile 5.2.1. SASL Protocol Profile
LDAP allows authentication via any SASL mechanism [SASL]. As LDAP LDAP allows authentication via any SASL mechanism [SASL]. As LDAP
includes native anonymous and name/password (plain text) includes native anonymous and name/password (plain text)
authentication methods, the ANONYMOUS [ANONYMOUS] and PLAIN [PLAIN] authentication methods, the ANONYMOUS [ANONYMOUS] and PLAIN [PLAIN]
SASL mechanisms are typically not used with LDAP. SASL mechanisms are typically not used with LDAP.
Each protocol that utilizes SASL services is required to supply Each protocol that utilizes SASL services is required to supply
certain information profiling the way they are exposed through the certain information profiling the way they are exposed through the
protocol ([SASL] section 5). This section explains how each of protocol ([SASL] section 4). This section explains how each of
these profiling requirements are met by LDAP. these profiling requirements are met by LDAP.
5.2.1.1. SASL Service Name for LDAP 5.2.1.1. SASL Service Name for LDAP
The SASL service name for LDAP is "ldap", which has been registered The SASL service name for LDAP is "ldap", which has been registered
with the IANA as a SASL service name. with the IANA as a SASL service name.
5.2.1.2. SASL Authentication Initiation and Protocol Exchange 5.2.1.2. SASL Authentication Initiation and Protocol Exchange
SASL authentication is initiated via a BindRequest message SASL authentication is initiated via a BindRequest message
skipping to change at page 15, line 4 skipping to change at page 15, line 39
The SASL service name for LDAP is "ldap", which has been registered The SASL service name for LDAP is "ldap", which has been registered
with the IANA as a SASL service name. with the IANA as a SASL service name.
5.2.1.2. SASL Authentication Initiation and Protocol Exchange 5.2.1.2. SASL Authentication Initiation and Protocol Exchange
SASL authentication is initiated via a BindRequest message SASL authentication is initiated via a BindRequest message
([Protocol] section 4.2) with the following parameters: ([Protocol] section 4.2) with the following parameters:
- The version is 3. - The version is 3.
- The AuthenticationChoice is sasl. - The AuthenticationChoice is sasl.
- The mechanism element of the SaslCredentials sequence contains - The mechanism element of the SaslCredentials sequence contains
the value of the desired SASL mechanism. the value of the desired SASL mechanism.
- The optional credentials field of the SaslCredentials sequence - The optional credentials field of the SaslCredentials sequence
MAY be used to provide an initial client response for MAY be used to provide an initial client response for
mechanisms that are defined to have the client send data first mechanisms that are defined to have the client send data first
(see [SASL] sections 5 and 5.1). (see [SASL] sections 3 and 5 ).
In general, a SASL authentication protocol exchange consists of a In general, a SASL authentication protocol exchange consists of a
series of server challenges and client responses, the contents of series of server challenges and client responses, the contents of
which are specific to and defined by the SASL mechanism. Thus for which are specific to and defined by the SASL mechanism. Thus for
some SASL authentication mechanisms, it may be necessary for the some SASL authentication mechanisms, it may be necessary for the
client to respond to one or more server challenges by sending client to respond to one or more server challenges by sending
BindRequest messages multiple times. A challenge is indicated by BindRequest messages multiple times. A challenge is indicated by
the server sending a BindResponse message with the resultCode set to the server sending a BindResponse message with the resultCode set to
saslBindInProgress. This indicates that the server requires the saslBindInProgress. This indicates that the server requires the
client to send a new BindRequest message with the same SASL client to send a new BindRequest message with the same SASL
skipping to change at page 15, line 54 skipping to change at page 16, line 47
abort a negotiation if it wishes to try again with the same SASL abort a negotiation if it wishes to try again with the same SASL
mechanism. mechanism.
The server indicates completion of the SASL challenge-response The server indicates completion of the SASL challenge-response
exchange by responding with a BindResponse in which the resultCode exchange by responding with a BindResponse in which the resultCode
value is not saslBindInProgress. value is not saslBindInProgress.
The serverSaslCreds field in the BindResponse can be used to include The serverSaslCreds field in the BindResponse can be used to include
an optional challenge with a success notification for mechanisms an optional challenge with a success notification for mechanisms
which are defined to have the server send additional data along with which are defined to have the server send additional data along with
the indication of successful completion. If a server does not the indication of successful completion.
intend to send a challenge in a BindResponse message, the server
SHALL omit the serverSaslCreds field (rather than including the
field with a zero-length value).
5.2.1.3. Octet Where Negotiated Security Layers Take Effect 5.2.1.3. Optional Fields
As discussed above, LDAP provides an optional field for carrying an
initial response in the message initiating the SASL exchange and
provides an optional field for carrying additional data in the
message indicating outcome of the authentication exchange. As the
mechanism-specific content in these fields may be zero-length, SASL
requires protocol specifications to detail how an empty field is
distinguished from an absent field.
Zero-length initial response data is distinguished from no initial
response data in the initiating message, a BindRequest PDU, by the
presence of the SaslCredentials.credentials OCTET STRING (of length
zero) in that PDU. If the client does not intend to send an
initial response with the BindRequest initiating the SASL exchange,
it MUST omit the SaslCredentials.credentials OCTET STRING (rather
than including an zero-length OCTET STRING).
Zero-length additional data is distinguished from no additional
response data in the outcome message, a BindResponse PDU, by the
presence of the serverSaslCreds OCTET STRING (of length zero) in
that PDU. If a server does not intend to send additional data in
the BindResponse message indicating outcome of the exchange, the
server SHALL omit the serverSaslCreds OCTET STRING (rather than
including a zero-length OCTET STRING).
5.2.1.4. Octet Where Negotiated Security Layers Take Effect
SASL layers take effect following the transmission by the server and SASL layers take effect following the transmission by the server and
reception by the client of the final BindResponse in the SASL reception by the client of the final BindResponse in the SASL
exchange with a resultCode of success. exchange with a resultCode of success.
Once a SASL layer providing data integrity or confidentiality Once a SASL layer providing data integrity or confidentiality
services takes effect, the layer remains in effect until a new layer services takes effect, the layer remains in effect until a new layer
is installed (i.e. at the first octet following the final is installed (i.e. at the first octet following the final
BindResponse of the Bind operation that caused the new layer to take BindResponse of the Bind operation that caused the new layer to take
effect). Thus, an established SASL layer is not affected by a effect). Thus, an established SASL layer is not affected by a
failed or non-SASL Bind. failed or non-SASL Bind.
5.2.1.4. Determination of Supported SASL Mechanisms 5.2.1.5. Determination of Supported SASL Mechanisms
Clients may determine the SASL mechanisms a server supports by Clients may determine the SASL mechanisms a server supports by
reading the supportedSASLMechanisms attribute from the root DSE reading the 'supportedSASLMechanisms' attribute from the root DSE
(DSA-Specific Entry) ([Models] section 5.1). The values of this (DSA-Specific Entry) ([Models] section 5.1). The values of this
attribute, if any, list the mechanisms the server supports in the attribute, if any, list the mechanisms the server supports in the
current LDAP session state. LDAP servers SHOULD allow all clients-- current LDAP session state. LDAP servers SHOULD allow all clients--
even those with an anonymous authorization--to retrieve the even those with an anonymous authorization--to retrieve the
supportedSASLMechanisms attribute of the root DSE. 'supportedSASLMechanisms' attribute of the root DSE.
Because SASL mechanisms provide critical security functions, clients Because SASL mechanisms provide critical security functions, clients
and servers should be configurable to specify what mechanisms are and servers should be configurable to specify what mechanisms are
acceptable and allow only those mechanisms to be used. Both clients acceptable and allow only those mechanisms to be used. Both clients
and servers must confirm that the negotiated security level meets and servers must confirm that the negotiated security level meets
their requirements before proceeding to use the session. their requirements before proceeding to use the session.
5.2.1.5. Rules for Using SASL Layers 5.2.1.6. Rules for Using SASL Layers
Upon installing a SASL layer, the client SHOULD discard or refresh Upon installing a SASL layer, the client SHOULD discard or refresh
all information about the server it obtained prior to the initiation all information about the server it obtained prior to the initiation
of the SASL negotiation and not obtained through secure mechanisms. of the SASL negotiation and not obtained through secure mechanisms.
If a lower level security layer (such as TLS) is installed, any SASL If a lower level security layer (such as TLS) is installed, any SASL
layer SHALL be layered on top of such security layers regardless of layer SHALL be layered on top of such security layers regardless of
the order of their negotiation. In all other respects, the SASL the order of their negotiation. In all other respects, the SASL
layer and other security layers act independently, e.g. if both a layer and other security layers act independently, e.g. if both a
TLS layer and a SASL layer are in effect then removing the SASL TLS layer and a SASL layer are in effect then removing the SASL
layer does not affect the continuing service of the TLS layer and layer does not affect the continuing service of the TLS layer and
vice versa. vice versa.
5.2.1.6. Support for Multiple Authentications 5.2.1.7. Support for Multiple Authentications
LDAP supports multiple SASL authentications as defined in [SASL] LDAP supports multiple SASL authentications as defined in [SASL]
section 6.3. section 4.
5.2.1.8. SASL Authorization Identities
5.2.1.7 SASL Authorization Identities
Some SASL mechanisms allow clients to request a desired Some SASL mechanisms allow clients to request a desired
authorization identity for the LDAP session. The decision to allow authorization identity for the LDAP session ([SASL] section 3.4.
or disallow the current authentication identity to have access to The decision to allow or disallow the current authentication
the requested authorization identity is a matter of local policy identity to have access to the requested authorization identity is a
([SASL] section 4.2). The authorization identity is a string of matter of local policy. The authorization identity is a string of
UTF-8 [RFC3629] encoded [Unicode] characters corresponding to the UTF-8 [RFC3629] encoded [Unicode] characters corresponding to the
following ABNF [RFC2234bis] grammar: following ABNF [RFC2234bis] grammar:
authzId = dnAuthzId / uAuthzId authzId = dnAuthzId / uAuthzId
; distinguished-name-based authz id. ; distinguished-name-based authz id
dnAuthzId = "dn:" distinguishedName dnAuthzId = "dn:" distinguishedName
; unspecified authorization id, UTF-8 encoded. ; unspecified authorization id, UTF-8 encoded
uAuthzId = "u:" userid uAuthzId = "u:" userid
userid = *UTF8 ; syntax unspecified userid = *UTF8 ; syntax unspecified
where the distinguishedName rule is defined in section 3 of [LDAPDN] where the distinguishedName rule is defined in section 3 of [LDAPDN]
and the UTF8 rule is defined in section 1.3 of [Models]. and the UTF8 rule is defined in section 1.4 of [Models].
The dnAuthzId choice is used to assert authorization identities in The dnAuthzId choice is used to assert authorization identities in
the form of a distinguished name to be matched in accordance with the form of a distinguished name to be matched in accordance with
the distinguishedNameMatch matching rule [Syntaxes]. There is no the distinguishedNameMatch matching rule [Syntaxes]. There is no
requirement that the asserted distinguishedName value be that of an requirement that the asserted distinguishedName value be that of an
entry in the directory. entry in the directory.
The uAuthzId choice allows clients to assert an authorization The uAuthzId choice allows clients to assert an authorization
identity that is not in distinguished name form. The format of identity that is not in distinguished name form. The format of
userid is defined only as a sequence of UTF-8 [RFC3629] encoded userid is defined only as a sequence of UTF-8 [RFC3629] encoded
[Unicode] characters, and any further interpretation is a local [Unicode] characters, and any further interpretation is a local
matter. For example, the userid could identify a user of a specific matter. For example, the userid could identify a user of a specific
directory service, be a login name, or be an email address. A directory service, be a login name or be an email address. A
uAuthzId SHOULD NOT be assumed to be globally unique. To compare uAuthzId SHOULD NOT be assumed to be globally unique. To compare
uAuthzID values, each uAuthzID value MUST be prepared as a "query" uAuthzID values, each uAuthzID value MUST be prepared as a "query"
string using [SASLPrep] and then the two values are compared octet- string using [RFC4013] and then the two values are compared octet-
wise. wise.
The above grammar is extensible. The authzId production may be The above grammar is extensible. The authzId production may be
extended to support additional forms of identities. Each form is extended to support additional forms of identities. Each form is
distinguished by its unique prefix (See 3.12 of [LDAPIANA] for distinguished by its unique prefix (see section 3.12 of [LDAPIANA]
registration requirements). for registration requirements).
5.2.2. SASL Semantics Within LDAP 5.2.2. SASL Semantics Within LDAP
Implementers must take care to maintain the semantics of SASL Implementers must take care to maintain the semantics of SASL
specifications when handling data that has different semantics in specifications when handling data that has different semantics in
the LDAP protocol. the LDAP protocol.
For example, the SASL DIGEST-MD5 authentication mechanism [RFC2829] For example, the SASL DIGEST-MD5 authentication mechanism [RFC2829]
utilizes an authentication identity (username) and a realm which are utilizes an authentication identity and a realm which are
syntactically simple strings and semantically simple username and syntactically simple strings and semantically simple username and
realm values ([DIGEST-MD5] section 2.1). These values are not LDAP realm values ([DIGEST-MD5] section 2.1). These values are not LDAP
DNs, and there is no requirement that they be represented or treated DNs, and there is no requirement that they be represented or treated
as such. as such.
After preparing these values as specified in [DIGEST-MD5], the
server may choose to use LDAP semantics to locate an entry with the
user's authentication information. For example, it may expect the
username to have the form of a DN and look up the named entry, or it
may search for "(cn=<username>)" below
"cn=<realm>,cn=auth,dc=example,dc=com". However, when the entry is
located, authentication may fail if the realm and username values do
not match according to DIGEST-MD5's semantics. For example, the two
DNs "cn=Bob,dc=example,dc=com" (upper case 'B') and
"cn=bob,dc=example,dc=com" (lower case 'b') are equivalent when
being compared semantically as LDAP DNs because the cn attribute is
defined to be case insensitive, however the two values are not
equivalent if they represent username values in DIGEST-MD5 because
DIGEST-MD5 matching is case-sensitive.
5.2.3. SASL EXTERNAL Authentication Mechanism 5.2.3. SASL EXTERNAL Authentication Mechanism
A client can use the SASL EXTERNAL [SASL] mechanism to request the A client can use the SASL EXTERNAL [SASL] mechanism to request the
LDAP server to authenticate and establish a resulting authorization LDAP server to authenticate and establish a resulting authorization
identity using security credentials exchanged by a lower security identity using security credentials exchanged by a lower security
layer (such as by TLS authentication or IP-level security layer (such as by TLS authentication or IP-level security
[RFC2401]). If the client's authentication credentials have not [RFC2401]). If the client's authentication credentials have not
been established at a lower security layer, the SASL EXTERNAL Bind been established at a lower security layer, the SASL EXTERNAL Bind
MUST fail with a resultCode of inappropriateAuthentication. MUST fail with a resultCode of inappropriateAuthentication.
Although this situation has the effect of leaving the LDAP session Although this situation has the effect of leaving the LDAP session
in an anonymous state (section 5), the state of any installed in an anonymous state (section 4), the state of any installed
security layer is unaffected. security layer is unaffected.
A client may either request that its authorization identity be A client may either request that its authorization identity be
automatically derived from its authentication credentials exchanged automatically derived from its authentication credentials exchanged
at a lower security layer or it may explicitly provide a desired at a lower security layer or it may explicitly provide a desired
authorization identity. The former is known as an implicit authorization identity. The former is known as an implicit
assertion, and the latter as an explicit assertion. assertion, and the latter as an explicit assertion.
5.2.3.1. Implicit Assertion 5.2.3.1. Implicit Assertion
An implicit authorization identity assertion is performed by An implicit authorization identity assertion is performed by
invoking a Bind request of the SASL form using the EXTERNAL invoking a Bind request of the SASL form using the EXTERNAL
mechanism name that does not include the optional credentials field mechanism name that does not include the optional credentials field
(found within the SaslCredentials sequence in the BindRequest). The (found within the SaslCredentials sequence in the BindRequest). The
server will derive the client's authorization identity from the server will derive the client's authorization identity from the
authentication identity supplied by a security layer (e.g., a public authentication identity supplied by a security layer (e.g. a public
key certificate used during TLS layer installation) according to key certificate used during TLS layer installation) according to
local policy. The underlying mechanics of how this is accomplished local policy. The underlying mechanics of how this is accomplished
are implementation specific. are implementation specific.
5.2.3.2. Explicit Assertion 5.2.3.2. Explicit Assertion
An explicit authorization identity assertion is performed by An explicit authorization identity assertion is performed by
invoking a Bind request of the SASL form using the EXTERNAL invoking a Bind request of the SASL form using the EXTERNAL
mechanism name that includes the credentials field (found within the mechanism name that includes the credentials field (found within the
SaslCredentials sequence in the BindRequest). The value of the SaslCredentials sequence in the BindRequest). The value of the
credentials field (an OCTET STRING) is the asserted authorization credentials field (an OCTET STRING) is the asserted authorization
identity and MUST be constructed as documented in section 5.2.1.7. identity and MUST be constructed as documented in section 5.2.1.8.
6. Security Considerations 6. Security Considerations
Security issues are discussed throughout this document. The Security issues are discussed throughout this document. The
unsurprising conclusion is that security is an integral and unsurprising conclusion is that security is an integral and
necessary part of LDAP. This section discusses a number of LDAP- necessary part of LDAP. This section discusses a number of LDAP-
related security considerations. related security considerations.
6.1. General LDAP Security Considerations 6.1. General LDAP Security Considerations
skipping to change at page 19, line 52 skipping to change at page 21, line 4
Access control should always be applied when reading sensitive Access control should always be applied when reading sensitive
information or updating directory information. information or updating directory information.
Various security factors, including authentication and authorization Various security factors, including authentication and authorization
information and data security services may change during the course information and data security services may change during the course
of the LDAP session, or even during the performance of a particular of the LDAP session, or even during the performance of a particular
operation. Implementations should be robust in the handling of operation. Implementations should be robust in the handling of
changing security factors. changing security factors.
6.2. StartTLS Security Considerations 6.2. StartTLS Security Considerations
All security gained via use of the StartTLS operation is gained by All security gained via use of the StartTLS operation is gained by
the use of TLS itself. The StartTLS operation, on its own, does not the use of TLS itself. The StartTLS operation, on its own, does not
provide any additional security. provide any additional security.
The level of security provided through the use of TLS depends The level of security provided through the use of TLS depends
directly on both the quality of the TLS implementation used and the directly on both the quality of the TLS implementation used and the
style of usage of that implementation. Additionally, a man-in-the- style of usage of that implementation. Additionally, a man-in-the-
middle attacker can remove the StartTLS extended operation from the middle attacker can remove the StartTLS extended operation from the
supportedExtension attribute of the root DSE. Both parties SHOULD 'supportedExtension' attribute of the root DSE. Both parties SHOULD
independently ascertain and consent to the security level achieved independently ascertain and consent to the security level achieved
once TLS is established and before beginning use of the TLS- once TLS is established and before beginning use of the TLS-
protected session. For example, the security level of the TLS layer protected session. For example, the security level of the TLS layer
might have been negotiated down to plaintext. might have been negotiated down to plaintext.
Clients SHOULD by default either warn the user when the security Clients SHOULD by default either warn the user when the security
level achieved does not provide an acceptable level of data level achieved does not provide an acceptable level of data
confidentiality and/or data integrity protection, or be configured confidentiality and/or data integrity protection, or be configured
to refuse to proceed without an acceptable level of security. to refuse to proceed without an acceptable level of security.
skipping to change at page 22, line 4 skipping to change at page 23, line 14
6.3.4. Hashed Password Security Considerations 6.3.4. Hashed Password Security Considerations
Some authentication mechanisms (e.g. DIGEST-MD5) transmit a hash of Some authentication mechanisms (e.g. DIGEST-MD5) transmit a hash of
the password value that may be vulnerable to offline dictionary the password value that may be vulnerable to offline dictionary
attacks. Implementers should take care to protect such hashed attacks. Implementers should take care to protect such hashed
password values during transmission using TLS or other password values during transmission using TLS or other
confidentiality mechanisms. confidentiality mechanisms.
6.4. Related Security Considerations 6.4. Related Security Considerations
Additional security considerations relating to the various Additional security considerations relating to the various
authentication methods and mechanisms discussed in this document authentication methods and mechanisms discussed in this document
apply and can be found in [SASL], [SASLPrep], [StringPrep] and apply and can be found in [SASL], [RFC4013], [StringPrep] and
[RFC3629]. [RFC3629].
7. IANA Considerations 7. IANA Considerations
It is requested that the IANA update the LDAP Protocol Mechanism It is requested that the IANA update the LDAP Protocol Mechanism
registry to indicate that this document and [Protocol] provide the registry to indicate that this document and [Protocol] provide the
definitive technical specification for the StartTLS definitive technical specification for the StartTLS
(1.3.6.1.4.1.1466.20037) extended operation. (1.3.6.1.4.1.1466.20037) extended operation.
8. Acknowledgments 8. Acknowledgments
This document combines information originally contained in RFC 2829 This document combines information originally contained in RFC 2251,
and RFC 2830. The editor acknowledges the work of Harald Tveit RFC 2829 and RFC 2830 which are products of the LDAP Extensions
Alvestrand, Jeff Hodges, Tim Howes, Steve Kille, RL "Bob" Morgan , (LDAPEXT) Working Group.
and Mark Wahl, each of whom authored one or more of these documents,
which are products of the LDAP Extentions (LDAPEXT) Working Group.
This document is a product of the IETF LDAP Revision (LDAPBIS) This document is a product of the IETF LDAP Revision (LDAPBIS)
working group. working group.
9. Normative References 9. Normative References
[[Note to the RFC Editor: please replace the citation tags used in [[Note to the RFC Editor: please replace the citation tags used in
referencing Internet-Drafts with tags of the form RFCnnnn.]] referencing Internet-Drafts with tags of the form RFCnnnn.]]
[LDAPDN] Zeilenga, Kurt D. (editor), "LDAP: String [LDAPDN] Zeilenga, Kurt D. (editor), "LDAP: String
skipping to change at page 23, line 19 skipping to change at page 24, line 29
[RFC2460] Deering, S., R. Hinden, "Internet Protocol, Version 6 [RFC2460] Deering, S., R. Hinden, "Internet Protocol, Version 6
(IPv6)", RFC 2460, December 1998. (IPv6)", RFC 2460, December 1998.
[RFC3490] Falstrom, P., P. Hoffman, and A. Costello, [RFC3490] Falstrom, P., P. Hoffman, and A. Costello,
"Internationalizing Domain Names In Applications "Internationalizing Domain Names In Applications
(IDNA)", RFC 3490, March 2003. (IDNA)", RFC 3490, March 2003.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", RFC 3629, STD 63, November 2003. 10646", RFC 3629, STD 63, November 2003.
[RFC4013] Zeilenga, K., "SASLprep: Stringprep Profile for User
Names and Passwords", RFC 4013, February 2005.
[Roadmap] K. Zeilenga, "LDAP: Technical Specification Road Map", [Roadmap] K. Zeilenga, "LDAP: Technical Specification Road Map",
draft-ietf-ldapbis-roadmap-xx.txt, a work in progress. draft-ietf-ldapbis-roadmap-xx.txt, a work in progress.
[SASL] Melnikov, A. (editor), "Simple Authentication and [SASL] Melnikov, A. (editor), "Simple Authentication and
Security Layer (SASL)", draft-ietf-sasl-rfc2222bis- Security Layer (SASL)", draft-ietf-sasl-rfc2222bis-
xx.txt, a work in progress. xx.txt, a work in progress.
[SASLPrep] Zeilenga, K., "Stringprep profile for user names and [Schema] Dally, K. (editor), "LDAP: User Schema", draft-ietf-
passwords", draft-ietf-sasl-saslprep-xx.txt, (a work in ldapbis-user-schema-xx.txt, a work in progress.
progress).
[StringPrep] M. Blanchet, "Preparation of Internationalized Strings [StringPrep] M. Blanchet, "Preparation of Internationalized Strings
('stringprep')", draft-hoffman-rfc3454bis-xx.txt, a ('stringprep')", draft-hoffman-rfc3454bis-xx.txt, a
work in progress. work in progress.
[Syntaxes] Legg, S. (editor), "LDAP: Syntaxes and Matching Rules", [Syntaxes] Legg, S. (editor), "LDAP: Syntaxes and Matching Rules",
draft-ietf-ldapbis-syntaxes-xx.txt, a work in progress. draft-ietf-ldapbis-syntaxes-xx.txt, a work in progress.
[TLS] Dierks, T. and C. Allen. "The TLS Protocol Version [TLS] Dierks, T. and C. Allen. "The TLS Protocol Version
1.1", draft-ietf-tls-rfc2246-bis-xx.txt, a work in 1.1", draft-ietf-tls-rfc2246-bis-xx.txt, a work in
skipping to change at page 23, line 52 skipping to change at page 25, line 16
3.2.0" is defined by "The Unicode Standard, Version 3.2.0" is defined by "The Unicode Standard, Version
3.0" (Reading, MA, Addison-Wesley, 2000. ISBN 0-201- 3.0" (Reading, MA, Addison-Wesley, 2000. ISBN 0-201-
61633-5), as amended by the "Unicode Standard Annex 61633-5), as amended by the "Unicode Standard Annex
#27: Unicode 3.1" #27: Unicode 3.1"
(http://www.unicode.org/reports/tr27/) and by the (http://www.unicode.org/reports/tr27/) and by the
"Unicode Standard Annex #28: Unicode 3.2" "Unicode Standard Annex #28: Unicode 3.2"
(http://www.unicode.org/reports/tr28/). (http://www.unicode.org/reports/tr28/).
10. Informative References 10. Informative References
[[Note to the RFC Editor: please replace the citation tags used in
referencing Internet-Drafts with tags of the form RFCnnnn.]]
[ANONYMOUS] Zeilenga, K., "Anonymous SASL Mechanism", draft- [ANONYMOUS] Zeilenga, K., "Anonymous SASL Mechanism", draft-
zeilenga-sasl-anon-xx.txt, a work in progress. zeilenga-sasl-anon-xx.txt, a work in progress.
[DIGEST-MD5] Leach, P. C. Newman, and A. Melnikov, "Using Digest [DIGEST-MD5] Leach, P. C. Newman, and A. Melnikov, "Using Digest
Authentication as a SASL Mechanism", draft-ietf-sasl- Authentication as a SASL Mechanism", draft-ietf-sasl-
rfc2831bis-xx.txt, a work in progress. rfc2831bis-xx.txt, a work in progress.
[PLAIN] Zeilenga, K.,"Plain SASL Mechanism", draft-zeilenga- [PLAIN] Zeilenga, K.,"Plain SASL Mechanism", draft-zeilenga-
sasl-plain-xx.txt, a work in progress. sasl-plain-xx.txt, a work in progress.
skipping to change at page 24, line 47 skipping to change at page 26, line 16
An access control policy is a set of rules defining the protection An access control policy is a set of rules defining the protection
of resources, generally in terms of the capabilities of persons or of resources, generally in terms of the capabilities of persons or
other entities accessing those resources. Security objects and other entities accessing those resources. Security objects and
mechanisms, such as those described here, enable the expression of mechanisms, such as those described here, enable the expression of
access control policies and their enforcement. access control policies and their enforcement.
A.2. Access Control Factors A.2. Access Control Factors
A request, when it is being processed by a server, may be associated A request, when it is being processed by a server, may be associated
with a wide variety of security-related factors (section 4.2 of with a wide variety of security-related factors ([Protocol] section
[Protocol]). The server uses these factors to determine whether and 4.2). The server uses these factors to determine whether and how to
how to process the request. These are called access control factors process the request. These are called access control factors
(ACFs). They might include source IP address, encryption strength, (ACFs). They might include source IP address, encryption strength,
the type of operation being requested, time of day, etc.. Some the type of operation being requested, time of day, etc.. Some
factors may be specific to the request itself, others may be factors may be specific to the request itself, others may be
associated with the transport connection via which the request is associated with the transport connection via which the request is
transmitted, others (e.g. time of day) may be "environmental". transmitted, others (e.g. time of day) may be "environmental".
Access control policies are expressed in terms of access control Access control policies are expressed in terms of access control
factors. For example, "a request having ACFs i,j,k can perform factors. For example, "a request having ACFs i,j,k can perform
operation Y on resource Z." The set of ACFs that a server makes operation Y on resource Z." The set of ACFs that a server makes
available for such expressions is implementation-specific. available for such expressions is implementation-specific.
skipping to change at page 25, line 20 skipping to change at page 26, line 40
A.3. Authentication, Credentials, Identity A.3. Authentication, Credentials, Identity
Authentication credentials are the evidence supplied by one party to Authentication credentials are the evidence supplied by one party to
another, asserting the identity of the supplying party (e.g. a user) another, asserting the identity of the supplying party (e.g. a user)
who is attempting to establish a new authorization state with the who is attempting to establish a new authorization state with the
other party (typically a server). Authentication is the process of other party (typically a server). Authentication is the process of
generating, transmitting, and verifying these credentials and thus generating, transmitting, and verifying these credentials and thus
the identity they assert. An authentication identity is the name the identity they assert. An authentication identity is the name
presented in a credential. presented in a credential.
There are many forms of authentication credentials -- the form used There are many forms of authentication credentials. The form used
depends upon the particular authentication mechanism negotiated by depends upon the particular authentication mechanism negotiated by
the parties. For example: X.509 certificates, Kerberos tickets, the parties. X.509 certificates, Kerberos tickets, and simple
simple identity and password pairs. Note that an authentication identity and password pairs are all examples of authentication
mechanism may constrain the form of authentication identities used credential forms. Note that an authentication mechanism may
with it. constrain the form of authentication identities used with it.
A.4. Authorization Identity A.4. Authorization Identity
An authorization identity is one kind of access control factor. It An authorization identity is one kind of access control factor. It
is the name of the user or other entity that requests that is the name of the user or other entity that requests that
operations be performed. Access control policies are often operations be performed. Access control policies are often
expressed in terms of authorization identities; for example, "entity expressed in terms of authorization identities; for example, "entity
X can perform operation Y on resource Z." X can perform operation Y on resource Z."
The authorization identity of an LDAP session is often semantically The authorization identity of an LDAP session is often semantically
the same as the authentication identity presented by the client, but the same as the authentication identity presented by the client, but
it may be different. SASL allows clients to specify an it may be different. SASL allows clients to specify an
authorization identity distinct from the authentication identity authorization identity distinct from the authentication identity
asserted by the client's credentials. This permits agents such as asserted by the client's credentials. This permits agents such as
proxy servers to authenticate using their own credentials, yet proxy servers to authenticate using their own credentials, yet
request the access privileges of the identity for which they are request the access privileges of the identity for which they are
proxying [SASL]. Also, the form of authentication identity supplied proxying [SASL]. Also, the form of authentication identity supplied
by a service like TLS may not correspond to the authorization by a service like TLS may not correspond to the authorization
identities used to express a server's access control policy, identities used to express a server's access control policy,
skipping to change at page 26, line 5 skipping to change at page 27, line 23
identities used to express a server's access control policy, identities used to express a server's access control policy,
requiring a server-specific mapping to be done. The method by which requiring a server-specific mapping to be done. The method by which
a server composes and validates an authorization identity from the a server composes and validates an authorization identity from the
authentication credentials supplied by a client is implementation authentication credentials supplied by a client is implementation
specific. specific.
Appendix B. Summary of Changes Appendix B. Summary of Changes
This appendix is non-normative. This appendix is non-normative.
This appendix summarizes substantive changes made to RFC 2829 and This appendix summarizes substantive changes made to RFC 2251, RFC
RFC 2830. In addition to the changes listed below, the reader of 2829 and RFC 2830. In addition to the specific changes detailed
this document should be aware that numerous editorial changes have below, the reader of this document should be aware that numerous
been made to the original content found in RFC 2829 and RFC 2830. general editorial changes have been made to the original content
These changes include the following: from the source documents. These changes include the following:
- The material originally found in RFC 2829 and RFC 2830 was - The material originally found in RFC 2251 sections 4.2.1 and
combined into a single document 4.2.2, RFC 2829 (all sections except sections 2 and 4) and RFC
2830 was combined into a single document
- The combined material was substantially reorganized and edited - The combined material was substantially reorganized and edited
to improve the document flow and clarify intent. to group related subjects, improve the document flow and clarify
intent.
- Changes were made throughout the text to align with definitions - Changes were made throughout the text to align with definitions
of LDAP protocol layers. of LDAP protocol layers and IETF security terminology.
- Substantial updates and additions were made to security - Substantial updates and additions were made to security
considerations from both documents based on current operational considerations from both documents based on current operational
experience. experience.
B.1. Changes made to RFC 2829 B.1. Changes Made to RFC 2251
This section summarizes the substantive changes made to Sections of This section summarizes the substantive changes made to sections
RFC 2829. 4.2.1 and 4.2.2 of RFC 2251 by this document. Additional
substantive changes to section 4.2.1 of RFC 2251 are also documented
in [Protocol].
B.1.1. Section 4 (Required security mechanisms) B.1.1. Section 4.2.1 (Sequencing of the Bind Request)
- Paragraph 1: Removed the sentence, "If at any stage the client
wishes to abort the bind process it MAY unbind and then drop the
underlying connection." The Unbind operation still permits this
behavior, but it is not documented explicitly.
- The name/password authentication mechanism (see section B.1.5 - Clarified that the session is moved to an anonymous state upon
receipt of the BindRequest PDU and that it is only moved to a
non-anonymous state if and when the Bind request is successful.
B.1.2. Section 4.2.2 (Authentication and Other Security Services)
- RFC 2251 states that anonymous authentication MUST be performed
using the simple bind method. This specification defines the
anonymous authentication mechanism of the simple bind method and
requires all conforming implementations to support it. Other
authentication mechanisms producing anonymous authentication and
authorization state may also be implemented and used by
conforming implementations.
B.2. Changes Made to RFC 2829
This section summarizes the substantive changes made to RFC 2829.
B.2.1. Section 4 (Required security mechanisms)
- The name/password authentication mechanism (see section B.2.5
below) protected by TLS replaces the SASL DIGEST-MD5 mechanism below) protected by TLS replaces the SASL DIGEST-MD5 mechanism
as LDAP's mandatory-to-implement password-based authentication as LDAP's mandatory-to-implement password-based authentication
mechanism. Implementations are encouraged to continue mechanism. Implementations are encouraged to continue
supporting SASL DIGEST-MD5 [RFC2829]. supporting SASL DIGEST-MD5 [RFC2829].
B.1.2. Section 5.1 (Anonymous authentication procedure) B.2.2. Section 5.1 (Anonymous authentication procedure)
- Clarified that anonymous authentication involves a name value of - Clarified that anonymous authentication involves a name value of
zero length and a password value of zero length. The zero length and a password value of zero length. The
unauthenticated authentication mechanism was added to handle unauthenticated authentication mechanism was added to handle
simple Bind requests involving a name value with a non-zero simple Bind requests involving a name value with a non-zero
length and a password value of zero length. length and a password value of zero length.
B.1.3. Section 6 (Password-based authentication) B.2.3. Section 6 (Password-based authentication)
- See section B.1.1.
B.1.4. Section 6.1 (Digest authentication) - See section B.2.1.
B.2.4. Section 6.1 (Digest authentication)
- As the SASL-DIGEST-MD5 mechanism is no longer mandatory to - As the SASL-DIGEST-MD5 mechanism is no longer mandatory to
implement, this section is now historical and was not included implement, this section is now historical and was not included
in this document. RFC 2829 section 6.1 continues to document the in this document. RFC 2829 section 6.1 continues to document the
SASL DIGEST-MD5 authentication mechanism. SASL DIGEST-MD5 authentication mechanism.
B.1.5. Section 6.2 ("simple" authentication choice with TLS) B.2.5. Section 6.2 ("simple" authentication choice with TLS)
- Renamed the "simple" authentication mechanism to the - Renamed the "simple" authentication mechanism to the
name/password authentication mechanism to better describe it. name/password authentication mechanism to better describe it.
- The use of TLS was generalized to align with definitions of LDAP - The use of TLS was generalized to align with definitions of LDAP
protocol layers. TLS establishment is now discussed as an protocol layers. TLS establishment is now discussed as an
independent subject and is generalized for use with all independent subject and is generalized for use with all
authentication mechanisms and other security layers. authentication mechanisms and other security layers.
- Removed the implication that the userPassword attribute is the - Removed the implication that the userPassword attribute is the
sole location for storage of password values to be used in sole location for storage of password values to be used in
authentication. There is no longer any implied requirement for authentication. There is no longer any implied requirement for
how or where passwords are stored at the server for use in how or where passwords are stored at the server for use in
authentication. authentication.
B.1.6. Section 6.3 (Other authentication choices with TLS) B.2.6. Section 6.3 (Other authentication choices with TLS)
- See section B.1.5. - See section B.2.5.
B.1.7. Section 7.1 (Certificate-based authentication with TLS) B.2.7. Section 7.1 (Certificate-based authentication with TLS)
- See section B.1.5. - See section B.2.5.
B.1.8. Section 8 (Other mechanisms) B.2.8. Section 8 (Other mechanisms)
- All SASL authentication mechanisms are explicitly allowed within - All SASL authentication mechanisms are explicitly allowed within
LDAP. Specifically, this means the SASL ANONYMOUS and SASL PLAIN LDAP. Specifically, this means the SASL ANONYMOUS and SASL PLAIN
mechanisms are no longer precluded from use within LDAP. mechanisms are no longer precluded from use within LDAP.
B.1.9. Section 9 (Authorization identity) B.2.9. Section 9 (Authorization identity)
- Specified matching rules for dnAuthzID and uAuthzID values. In - Specified matching rules for dnAuthzID and uAuthzID values. In
particular, the DN value in the dnAuthzID form must be matched particular, the DN value in the dnAuthzID form must be matched
using DN matching rules and the uAuthzID value MUST be prepared using DN matching rules and the uAuthzID value MUST be prepared
using SASLprep rules before being compared octet-wise. using SASLprep rules before being compared octet-wise.
- Clarified that uAuthzID values should not be assumed to be - Clarified that uAuthzID values should not be assumed to be
globally unique. globally unique.
B.1.10. Section 10 (TLS Ciphersuites) B.2.10. Section 10 (TLS Ciphersuites)
- TLS Ciphersuite recommendations are no longer included in this - TLS Ciphersuite recommendations are no longer included in this
specification. Implementations must still support the specification. Implementations must still support the
TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA ciphersuite. TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA ciphersuite.
- Clarified that anonymous authentication involves a name value of - Clarified that anonymous authentication involves a name value of
zero length and a password value of zero length. The zero length and a password value of zero length. The
unauthenticated authentication mechanism was added to handle unauthenticated authentication mechanism was added to handle
simple Bind requests involving a name value with a non-zero simple Bind requests involving a name value with a non-zero
length and a password value of zero length. length and a password value of zero length.
B.2. Changes made to RFC 2830: B.3. Changes Made to RFC 2830:
This section summarizes the substantive changes made to Sections of This section summarizes the substantive changes made to sections 3
RFC 2830. Readers should consult [Protocol] for summaries of changes and 5 of RFC 2830. Readers should consult [Protocol] for summaries
to other sections. of changes to other sections.
B.2.1. Section 3.6 (Server Identity Check) B.3.1. Section 3.6 (Server Identity Check)
- Substantially updated the server identity check algorithm to - Substantially updated the server identity check algorithm to
ensure that it is complete and robust. In particular, the use ensure that it is complete and robust. In particular, the use
of all relevant values in the subjectAltName and the subjectName of all relevant values in the subjectAltName and the subjectName
fields are covered by the algorithm and matching rules are fields are covered by the algorithm and matching rules are
specified for each type of value. Mapped (derived) forms of the specified for each type of value. Mapped (derived) forms of the
server identity may now be used when the mapping is performed in server identity may now be used when the mapping is performed in
a secure fashion. a secure fashion.
B.2.2. Section 3.7 (Refresh of Server Capabilities Information) B.3.2. Section 3.7 (Refresh of Server Capabilities Information)
- Clients are no longer required to always refresh information - Clients are no longer required to always refresh information
about server capabilities following TLS establishment to allow about server capabilities following TLS establishment to allow
for situations where this information was obtained through a for situations where this information was obtained through a
secure mechanism. secure mechanism.
B.2.3. Section 5.2 (Effects of TLS on Authorization Identity) B.3.3. Section 5.2 (Effects of TLS on Authorization Identity)
- Establishing a TLS layer on an LDAP session may now cause the - Establishing a TLS layer on an LDAP session may now cause the
authorization state of the LDAP session to change. authorization state of the LDAP session to change.
B.2.4. Section 5.1.1 (TLS Closure Effects) B.3.4. Section 5.1.1 (TLS Closure Effects)
- Closing a TLS layer on an LDAP session changes the - Closing a TLS layer on an LDAP session changes the
authentication and authorization state of the LDAP session based authentication and authorization state of the LDAP session based
on local policy. Specifically, this means that implementations on local policy. Specifically, this means that implementations
are not required to to change the authentication and are not required to to change the authentication and
authorization states to anonymous upon TLS closure. authorization states to anonymous upon TLS closure.
Appendix C. Changes for draft-ldapbis-authmeth-17 Appendix C. Changes for draft-ldapbis-authmeth-18
[[Note to RFC Editor: Please remove this appendix upon publication [[Note to RFC Editor: Please remove this appendix upon publication
of this Internet-Draft as an RFC.]] of this Internet-Draft as an RFC.]]
This appendix is non-normative. This appendix is non-normative.
This appendix summarizes changes made in this revision of the This appendix summarizes changes made in this revision of the
document. document.
General General
- Resolved all known outstanding issues and comments for -16 draft. - Resolved all known outstanding issues and comments for -17 draft.
- Edits for clarity and consistency. - Edits for clarity and consistency.
- Removed -16 section 3.2 (StartTLS Response) as this material is
now covered in [Protocol]. Section 1.1
- Reordered several document sections to improve document flow. - Added paragraph detailing which RFCs are obsoleted by this
document.
Section 2 Section 2
- Fixed requirements consistency issue with name/password - Deleted a sentence at the end of paragraph 2 that is redundant
mechanism and TLS that was caused by moving LDAP's required with the first sentence of paragraph 3.
mechanism from DIGEST-MD5 mechanism to name/password mechanism
in -16.
Section 3.1.3 Section 3.1.3.1
- Restored a wildcard matching example that was inadvertently
deleted by extensive edits to this section in -16 draft.
- Refinements to server identity check algorithm based on feedback Section 5.1.2
from WG reviewers. - Substantially edited this section to clarify the proper (and
improper) use of the distinguished name in the unauthenticated
authentication mechanism.
- Clarified client and server behavior to protect against security
risks associated with the unauthenticated authentication
mechanism.
Section 5.2.2 Section 5.2.1.2
- Moved last sentence of this section into a new section 5.2.1.3
detailing optional fields used by LDAP.
- Added a new section on SASL semantics within LDAP based on a Section 5.2.2
generalization of some material on DIGEST-MD5 semantics within - Removed the third paragraph because it provided an example that
LDAP that was removed in the -16 draft. was misleading in that it implied that one could accurately
match data prepared for use with SASL mechanisms using LDAP
matching semantics.
Appendix B Appendix B
- Completed list of substantive changes to RFC 2829 and RFC 2830. - Added a list of substantive changes to RFC 2251.
Removed all other appendices that were tracking changes to this
document.
Intellectual Property Rights Intellectual Property Rights
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed Intellectual Property Rights or other rights that might be claimed
to pertain to the implementation or use of the technology described to pertain to the implementation or use of the technology described
in this document or the extent to which any license under such in this document or the extent to which any license under such
rights might or might not be available; nor does it represent that rights might or might not be available; nor does it represent that
it has made any independent effort to identify any such rights. it has made any independent effort to identify any such rights.
Information on the procedures with respect to rights in RFC Information on the procedures with respect to rights in RFC
documents can be found in BCP 78 and BCP 79. documents can be found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any Copies of IPR disclosures made to the IETF Secretariat and any
 End of changes. 107 change blocks. 
248 lines changed or deleted 304 lines changed or added

This html diff was produced by rfcdiff 1.27, available from http://www.levkowetz.com/ietf/tools/rfcdiff/