One document matched: draft-ietf-cat-gssv2-javabind-02.txt
Differences from draft-ietf-cat-gssv2-javabind-01.txt
Internet-Draft Jack Kabat
IETF CAT Working Group ValiCert, Inc.
Document: <draft-ietf-cat-gssv2-javabind-02.txt> Mayank Upadhyay
Sun Microsystems, Inc.
July 1999
Generic Security Service API Version 2 : Java bindings
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet- Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
Abstract
The Generic Security Services Application Program Interface (GSS-API)
offers application programmers uniform access to security services
atop a variety of underlying cryptographic mechanisms. This document
specifies the Java bindings for GSS-API which is described at a
language independent conceptual level in RFC 2078 [GSSAPIv2].
The GSS-API allows a caller application to authenticate a principal
identity, to delegate rights to a peer, and to apply security
services such as confidentiality and integrity on a per-message
basis. Examples of security mechanisms defined for GSS-API are The
Simple Public-Key GSS-API Mechanism [SPKM] and The Kerberos Version 5
GSS-API Mechanism [KERBV5].
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 6
2. GSS-API Operational Paradigm . . . . . . . . . . . . . . . . 7
3. Additional Controls . . . . . . . . . . . . . . . . . . . . 8
3.1. Delegation . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2. Mutual Authentication . . . . . . . . . . . . . . . . . 10
3.3. Replay and Out-of-Sequence Detection . . . . . . . . . . 11
3.4. Anonymous Authentication . . . . . . . . . . . . . . . . 11
3.5. Confidentiality . . . . . . . . . . . . . . . . . . . . 12
3.6. Inter-process Context Transfer . . . . . . . . . . . . . 13
3.7. The Use of Incomplete Contexts . . . . . . . . . . . . . 13
4. Calling Conventions . . . . . . . . . . . . . . . . . . . 14
4.1. Package Name . . . . . . . . . . . . . . . . . . . . . . 14
4.2. Provider Framework . . . . . . . . . . . . . . . . . . . 14
4.3. Integer types . . . . . . . . . . . . . . . . . . . . . 15
4.4. Opaque Data types . . . . . . . . . . . . . . . . . . . 15
4.5. Strings . . . . . . . . . . . . . . . . . . . . . . . . 15
4.6. Object Identifiers . . . . . . . . . . . . . . . . . . . 16
4.7. Object Identifier Sets . . . . . . . . . . . . . . . . . 16
4.8. Credentials . . . . . . . . . . . . . . . . . . . . . . 16
4.9. Contexts . . . . . . . . . . . . . . . . . . . . . . . . 18
4.10. Authentication tokens . . . . . . . . . . . . . . . . . 19
4.11. Interprocess tokens . . . . . . . . . . . . . . . . . . 19
4.12. Error Reporting . . . . . . . . . . . . . . . . . . . . 20
4.12.1. GSS status codes . . . . . . . . . . . . . . . . . . 20
4.12.2. Mechanism-specific status codes . . . . . . . . . . . 22
4.12.3. Supplementary status codes . . . . . . . . . . . . . 22
4.13. Names . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.14. Channel Bindings . . . . . . . . . . . . . . . . . . . 26
4.15. Stream Objects . . . . . . . . . . . . . . . . . . . . 27
4.16. Optional Parameters . . . . . . . . . . . . . . . . . . 27
5. GSS Provider's Interface . . . . . . . . . . . . . . . . . 27
5.1. GSSFactory interface . . . . . . . . . . . . . . . . . . 28
5.2. IGSSName interface . . . . . . . . . . . . . . . . . . . 28
5.3. IGSSCredential interface . . . . . . . . . . . . . . . . 29
5.4. IGSSContext interface . . . . . . . . . . . . . . . . . 30
6. GSS Application Programmer's Classes . . . . . . . . . . . 31
6.1. GSSManager class . . . . . . . . . . . . . . . . . . . . 32
6.2. GSSName class . . . . . . . . . . . . . . . . . . . . . 32
6.3. GSSCredential class . . . . . . . . . . . . . . . . . . 32
6.4. GSSContext class . . . . . . . . . . . . . . . . . . . . 32
6.5. MessageProp class . . . . . . . . . . . . . . . . . . . 33
6.6. GSSException class . . . . . . . . . . . . . . . . . . . 33
6.7. Oid class . . . . . . . . . . . . . . . . . . . . . . . 33
6.8. ChannelBinding class . . . . . . . . . . . . . . . . . . 33
7. Detailed GSS-API Class Description . . . . . . . . . . . . 34
7.1. public interface GSSFactory . . . . . . . . . . . . . . 34
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7.1.1. createName . . . . . . . . . . . . . . . . . . . . . . 34
7.1.2. createName . . . . . . . . . . . . . . . . . . . . . . 35
7.1.3. createName . . . . . . . . . . . . . . . . . . . . . . 36
7.1.4. createName . . . . . . . . . . . . . . . . . . . . . . 36
7.1.5. createCredential . . . . . . . . . . . . . . . . . . . 37
7.1.6. createCredential . . . . . . . . . . . . . . . . . . . 37
7.1.7. createCredential . . . . . . . . . . . . . . . . . . . 38
7.1.8. createContext . . . . . . . . . . . . . . . . . . . . 38
7.1.9. createContext . . . . . . . . . . . . . . . . . . . . 39
7.1.10. createContext . . . . . . . . . . . . . . . . . . . . 39
7.1.11. getMechs . . . . . . . . . . . . . . . . . . . . . . 39
7.1.12. getMechsForName . . . . . . . . . . . . . . . . . . . 40
7.1.13. getNamesForMech . . . . . . . . . . . . . . . . . . . 40
7.2. public interface IGSSName extends java.security.Principal 40
7.2.1. Static Constants . . . . . . . . . . . . . . . . . . . 41
7.2.2. equals . . . . . . . . . . . . . . . . . . . . . . . . 42
7.2.3. equals . . . . . . . . . . . . . . . . . . . . . . . . 42
7.2.4. canonicalize . . . . . . . . . . . . . . . . . . . . . 42
7.2.5. export . . . . . . . . . . . . . . . . . . . . . . . . 43
7.2.6. toString . . . . . . . . . . . . . . . . . . . . . . . 43
7.2.7. getStringNameType . . . . . . . . . . . . . . . . . . 43
7.2.8. isAnonymous . . . . . . . . . . . . . . . . . . . . . 43
7.2.9. isMN . . . . . . . . . . . . . . . . . . . . . . . . . 44
7.3. public interface IGSSCredential implements Cloneable . . 44
7.3.1. Static Constants . . . . . . . . . . . . . . . . . . . 45
7.3.2. dispose . . . . . . . . . . . . . . . . . . . . . . . 45
7.3.3. getName . . . . . . . . . . . . . . . . . . . . . . . 45
7.3.4. getName . . . . . . . . . . . . . . . . . . . . . . . 46
7.3.5. getRemainingLifetime . . . . . . . . . . . . . . . . . 46
7.3.6. getRemainingInitLifetime . . . . . . . . . . . . . . . 46
7.3.7. getRemainingAcceptLifetime . . . . . . . . . . . . . . 46
7.3.8. getUsage . . . . . . . . . . . . . . . . . . . . . . . 47
7.3.9. getUsage . . . . . . . . . . . . . . . . . . . . . . . 47
7.3.10. getMechs . . . . . . . . . . . . . . . . . . . . . . 47
7.3.11. add . . . . . . . . . . . . . . . . . . . . . . . . . 47
7.3.12. equals . . . . . . . . . . . . . . . . . . . . . . . 48
7.4. public interface IGSSContext . . . . . . . . . . . . . . 49
7.4.1. Static Constants . . . . . . . . . . . . . . . . . . . 50
7.4.2. initSecContext . . . . . . . . . . . . . . . . . . . . 50
7.4.2.1. Example Code . . . . . . . . . . . . . . . . . . . . 51
7.4.3. initSecContext . . . . . . . . . . . . . . . . . . . . 51
7.4.3.1. Example Code . . . . . . . . . . . . . . . . . . . . 52
7.4.4. acceptSecContext . . . . . . . . . . . . . . . . . . . 53
7.4.4.1. Example Code . . . . . . . . . . . . . . . . . . . . 54
7.4.5. acceptSecContext . . . . . . . . . . . . . . . . . . . 54
7.4.5.1. Example Code . . . . . . . . . . . . . . . . . . . . 55
7.4.6. isEstablished . . . . . . . . . . . . . . . . . . . . 56
7.4.7. dispose . . . . . . . . . . . . . . . . . . . . . . . 56
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7.4.8. getWrapSizeLimit . . . . . . . . . . . . . . . . . . . 56
7.4.9. wrap . . . . . . . . . . . . . . . . . . . . . . . . . 57
7.4.10. wrap . . . . . . . . . . . . . . . . . . . . . . . . 58
7.4.11. unwrap . . . . . . . . . . . . . . . . . . . . . . . 59
7.4.12. unwrap . . . . . . . . . . . . . . . . . . . . . . . 59
7.4.13. getMIC . . . . . . . . . . . . . . . . . . . . . . . 60
7.4.14. getMIC . . . . . . . . . . . . . . . . . . . . . . . 61
7.4.15. verifyMIC . . . . . . . . . . . . . . . . . . . . . . 61
7.4.16. verifyMIC . . . . . . . . . . . . . . . . . . . . . . 62
7.4.17. export . . . . . . . . . . . . . . . . . . . . . . . 63
7.4.18. requestMutualAuth . . . . . . . . . . . . . . . . . . 64
7.4.19. requestReplayDet . . . . . . . . . . . . . . . . . . 64
7.4.20. requestSequenceDet . . . . . . . . . . . . . . . . . 64
7.4.21. requestCredDeleg . . . . . . . . . . . . . . . . . . 65
7.4.22. requestAnonymity . . . . . . . . . . . . . . . . . . 65
7.4.23. requestConf . . . . . . . . . . . . . . . . . . . . . 65
7.4.24. requestInteg . . . . . . . . . . . . . . . . . . . . 66
7.4.25. requestLifetime . . . . . . . . . . . . . . . . . . . 66
7.4.26. setChannelBinding . . . . . . . . . . . . . . . . . . 66
7.4.27. getCredDelegState . . . . . . . . . . . . . . . . . . 66
7.4.28. getMutualAuthState . . . . . . . . . . . . . . . . . 67
7.4.29. getReplayDetState . . . . . . . . . . . . . . . . . . 67
7.4.30. getSequenceDetState . . . . . . . . . . . . . . . . . 67
7.4.31. getAnonymityState . . . . . . . . . . . . . . . . . . 67
7.4.32. isTransferable . . . . . . . . . . . . . . . . . . . 67
7.4.33. isProtReady . . . . . . . . . . . . . . . . . . . . . 68
7.4.34. getConfState . . . . . . . . . . . . . . . . . . . . 68
7.4.35. getIntegState . . . . . . . . . . . . . . . . . . . . 68
7.4.36. getLifetime . . . . . . . . . . . . . . . . . . . . . 68
7.4.37. getSrcName . . . . . . . . . . . . . . . . . . . . . 68
7.4.38. getTargName . . . . . . . . . . . . . . . . . . . . . 69
7.4.39. getMech . . . . . . . . . . . . . . . . . . . . . . . 69
7.4.40. getDelegCred . . . . . . . . . . . . . . . . . . . . 69
7.4.41. isInitiator . . . . . . . . . . . . . . . . . . . . . 69
7.5. public class MessageProp . . . . . . . . . . . . . . . . 69
7.5.1. Constructors . . . . . . . . . . . . . . . . . . . . . 70
7.5.2. getQOP . . . . . . . . . . . . . . . . . . . . . . . . 70
7.5.3. getPrivacy . . . . . . . . . . . . . . . . . . . . . . 70
7.5.4. setQOP . . . . . . . . . . . . . . . . . . . . . . . . 71
7.5.5. setPrivacy . . . . . . . . . . . . . . . . . . . . . . 71
7.5.6. isDuplicateToken . . . . . . . . . . . . . . . . . . . 71
7.5.7. isOldToken . . . . . . . . . . . . . . . . . . . . . . 71
7.5.8. isUnseqToken . . . . . . . . . . . . . . . . . . . . . 71
7.5.9. isGapToken . . . . . . . . . . . . . . . . . . . . . . 72
7.5.10. setSupplementaryStates . . . . . . . . . . . . . . . 72
7.6. public class ChannelBinding . . . . . . . . . . . . . . 72
7.6.1. Constructors . . . . . . . . . . . . . . . . . . . . . 73
7.6.2. getInitiatorAddress . . . . . . . . . . . . . . . . . 73
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7.6.3. getAcceptorAddress . . . . . . . . . . . . . . . . . . 74
7.6.4. getApplicationData . . . . . . . . . . . . . . . . . . 74
7.6.5. equals . . . . . . . . . . . . . . . . . . . . . . . . 74
7.7. public class Oid . . . . . . . . . . . . . . . . . . . . 74
7.7.1. Constructors . . . . . . . . . . . . . . . . . . . . . 75
7.7.2. toString . . . . . . . . . . . . . . . . . . . . . . . 75
7.7.3. equals . . . . . . . . . . . . . . . . . . . . . . . . 75
7.7.4. getDER . . . . . . . . . . . . . . . . . . . . . . . . 76
7.7.5. containedIn . . . . . . . . . . . . . . . . . . . . . 76
7.8. public class GSSException extends Exception . . . . . . 76
7.8.1. Static Constants . . . . . . . . . . . . . . . . . . . 76
7.8.2. Constructors . . . . . . . . . . . . . . . . . . . . . 79
7.8.3. getMajor . . . . . . . . . . . . . . . . . . . . . . . 80
7.8.4. getMinor . . . . . . . . . . . . . . . . . . . . . . . 80
7.8.5. getMajorString . . . . . . . . . . . . . . . . . . . . 80
7.8.6. getMinorString . . . . . . . . . . . . . . . . . . . . 80
7.8.7. setMinor . . . . . . . . . . . . . . . . . . . . . . . 81
7.8.8. toString . . . . . . . . . . . . . . . . . . . . . . . 81
7.8.9. getMessage . . . . . . . . . . . . . . . . . . . . . . 81
7.9. public abstract class GSSManager . . . . . . . . . . . . 81
7.9.1. Example . . . . . . . . . . . . . . . . . . . . . . . 82
7.9.2. setDefaultProvider . . . . . . . . . . . . . . . . . . 82
7.9.3. getDefaultProvider . . . . . . . . . . . . . . . . . . 83
7.9.4. getMechs . . . . . . . . . . . . . . . . . . . . . . . 83
7.9.5. getNamesForMech . . . . . . . . . . . . . . . . . . . 83
7.9.6. getMechsForName . . . . . . . . . . . . . . . . . . . 83
7.9.7. getProviderFromToken . . . . . . . . . . . . . . . . . 84
7.9.8. getProviderForMechanism . . . . . . . . . . . . . . . 84
7.10. public class GSSName implements IGSSName . . . . . . . 85
7.10.1. Example . . . . . . . . . . . . . . . . . . . . . . . 86
7.10.2. Constructors . . . . . . . . . . . . . . . . . . . . 87
7.10.3. getProvider . . . . . . . . . . . . . . . . . . . . . 89
7.11. public class GSSCredential implements IGSSCredential . 89
7.11.1. Example . . . . . . . . . . . . . . . . . . . . . . . 90
7.11.2. Constructors . . . . . . . . . . . . . . . . . . . . 91
7.11.3. getProvider . . . . . . . . . . . . . . . . . . . . . 93
7.12. public class GSSContext implements IGSSContext . . . . 93
7.12.1. Example . . . . . . . . . . . . . . . . . . . . . . . 96
7.12.2. Constructors . . . . . . . . . . . . . . . . . . . . 97
7.12.3. getProvider . . . . . . . . . . . . . . . . . . . . . 99
8. Sample Applications . . . . . . . . . . . . . . . . . . . 99
8.1. Simple GSS Context Initiator . . . . . . . . . . . . . . 100
8.2. GSS Context Acceptor Using Multiple Providers . . . . . 104
8.3. GSS Context Initiator Using the Provider Factory Directly 108
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . 112
10. Bibliography . . . . . . . . . . . . . . . . . . . . . . 114
11. Author's Address . . . . . . . . . . . . . . . . . . . . 115
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1. Introduction
This document specifies Java language bindings for the Generic
Security Services Application Programming Interface (GSS-API) Version
2. GSS-API Version 2 is described in a language independent format in
RFC 2078 [GSSAPIv2]. The GSS-API allows a caller application to
authenticate a principal identity, to delegate rights to a peer, and
to apply security services such as confidentiality and integrity on a
per-message basis.
This document leverages the work performed by the WG in the area of
RFC 2078 [GSSAPIv2] the C-bindings draft [GSSAPI-C]. Whenever
appropriate, text has been used from the C-bindings document to
explain generic concepts and provide direction to the implementors.
The design goals of this API have been to satisfy all the
functionality defined in RFC 2078 and to provide these services in an
object oriented method. The specification also aims to satisfy the
needs of both types of Java application developers, those who would
like access to a "system-wide" GSS-API implementation, as well as
those who would want to provide their own "custom" implementation.
A "system-wide" implementation is one that is available to all
applications in the form of a library package. It may be a standard
package in the Java runtime environment (JRE) being used or it may be
additionally installed and accessible to any application via the
CLASSPATH.
A "custom" implementation of the GSS-API, on the other hand, is one
that would, in most cases, be bundled with the application during
distribution. It is expected that such an implementation would be
meant to provide for some particular need of the application, such as
support for some specific mechanism.
The design of this API also aims to allow applications to add to and
choose between GSS-API implementations at runtime. Key elements from
one implementation may be added to the remaining framework from
another implementation ("system-wide") to support new mechanisms with
minimum addition of binaries. This is particularly useful to applet
developers who need flexibility in choice but prefer to remain
lightweight.
Lastly, this specification presents an API that will naturally fit
within the operation environment of the Java platform. Readers are
assumed to be familiar with both the GSS-API and the Java platform.
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2. GSS-API Operational Paradigm
The Generic Security Service Application Programming Interface
[GSSAPIv2] defines a generic security API to calling applications.
It allows a communicating application to authenticate the user
associated with another application, to delegate rights to another
application, and to apply security services such as confidentiality
and integrity on a per-message basis.
There are four stages to using GSS-API:
1) The application acquires a set of credentials with which it
may prove its identity to other processes. The
application's credentials vouch for its global identity,
which may or may not be related to any local username under
which it may be running.
2) A pair of communicating applications establish a joint
security context using their credentials. The security
context encapsulates shared state information, which is
required in order that per-message security services may be
provided. Examples of state information that might be
shared between applications as part of a security context
are cryptographic keys, and message sequence numbers. As
part of the establishment of a security context, the
context initiator is authenticated to the responder, and
may require that the responder is authenticated back to the
initiator. The initiator may optionally give the responder
the right to initiate further security contexts, acting as
an agent or delegate of the initiator. This transfer of
rights is termed "delegation", and is achieved by creating
a set of credentials, similar to those used by the
initiating application, but which may be used by the
responder.
A GSSContext object is used to establish and maintain the
shared information that makes up the security context.
(Please note that for the purposes of this discussion,
GSSContext and IGSSContext are used interchangeably).
Certain GSSContext methods will generate a token, which
applications treat as cryptographically protected, opaque
data. The caller of such GSSContext method is responsible
for transferring the token to the peer application,
encapsulated if necessary in an application-to-application
protocol. On receipt of such a token, the peer application
should pass it to a corresponding GSSContext method which
will decode the token and extract the information, updating
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the security context state information accordingly.
3) Per-message services are invoked on a GSSContext object to
apply either:
integrity and data origin authentication, or
confidentiality, integrity and data origin
authentication
to application data, which are treated by GSS-API as
arbitrary octet-strings. An application transmitting a
message that it wishes to protect will call the appropriate
GSSContext method (getMIC or wrap) to apply protection, and
send the resulting token to the receiving application. The
receiver will pass the received token (and, in the case of
data protected by getMIC, the accompanying message-data) to
the corresponding decoding method of the GSSContext class
(verifyMIC or unwrap) to remove the protection and validate
the data.
4) At the completion of a communications session (which may
extend across several transport connections), each
application uses a GSSContext method to invalidate the
security context and release any system or cryptographic
resources held. Multiple contexts may also be used (either
successively or simultaneously) within a single
communications association, at the discretion of the
applications.
3. Additional Controls
This section discusses the optional services that a context initiator
may request of the GSS-API before the context establishment. Each of
these services is requested by calling the appropriate mutator method
in the GSSContext object before the first call to init is performed.
Only the context initiator can request context flags.
The optional services defined are:
Delegation
The (usually temporary) transfer of rights from initiator to
acceptor, enabling the acceptor to authenticate itself as an
agent of the initiator.
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Mutual Authentication
In addition to the initiator authenticating its identity to the
context acceptor, the context acceptor should also authenticate
itself to the initiator.
Replay Detection
In addition to providing message integrity services, GSSContext
per-message operations of getMIC and wrap should include message
numbering information to enable verifyMIC and unwrap to detect
if a message has been duplicated.
Out-of-Sequence Detection
In addition to providing message integrity services, GSSContext
per-message operations (getMIC and wrap) should include message
sequencing information to enable verifyMIC and unwrap to detect
if a message has been received out of sequence.
Anonymous Authentication
The establishment of the security context should not reveal the
initiator's identity to the context acceptor.
Some mechanisms may not support all optional services, and some
mechanisms may only support some services in conjunction with others.
The GSSContext class offers query methods to allow the verification
by the calling application of which services will be available from
the context when the establishment phase is complete. In general, if
the security mechanism is capable of providing a requested service,
it should do so even if additional services must be enabled in order
to provide the requested service. If the mechanism is incapable of
providing a requested service, it should proceed without the service
leaving the application to abort the context establishment process if
it considers the requested service to be mandatory.
Some mechanisms may specify that support for some services is
optional, and that implementors of the mechanism need not provide it.
This is most commonly true of the confidentiality service, often
because of legal restrictions on the use of data-encryption, but may
apply to any of the services. Such mechanisms are required to send
at least one token from acceptor to initiator during context
establishment when the initiator indicates a desire to use such a
service, so that the initiating GSS-API can correctly indicate
whether the service is supported by the acceptor's GSS-API.
3.1. Delegation
The GSS-API allows delegation to be controlled by the initiating
application via the requestCredDeleg method before the first call to
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init has been issued. Some mechanisms do not support delegation, and
for such mechanisms attempts by an application to enable delegation
are ignored.
The acceptor of a security context, for which the initiator enabled
delegation, can check if delegation was enabled by using the
getCredDelegState method of the GSSContext class. In cases when it
is, the delegated credential object can be obtained by calling the
getDelegCred method. The obtained IGSSCredential object may then be
used to initiate subsequent GSS-API security contexts as an agent or
delegate of the initiator. (Please note that for the purposes of
this discussion GSSCredential and IGSSCredential are used
interchangeably.) If the original initiator's identity is "A" and
the delegate's identity is "B", then, depending on the underlying
mechanism, the identity embodied by the delegated credential may be
either "A" or "B acting for A".
For many mechanisms that support delegation, a simple boolean does
not provide enough control. Examples of additional aspects of
delegation control that a mechanism might provide to an application
are duration of delegation, network addresses from which delegation
is valid, and constraints on the tasks that may be performed by a
delegate. Such controls are presently outside the scope of the GSS-
API. GSS-API implementations supporting mechanisms offering
additional controls should provide extension routines that allow
these controls to be exercised (perhaps by modifying the initiator's
GSS-API credential object prior to its use in establishing a
context). However, the simple delegation control provided by GSS-API
should always be able to over-ride other mechanism-specific
delegation controls. If the application instructs the GSSContext
object that delegation is not desired, then the implementation must
not permit delegation to occur. This is an exception to the general
rule that a mechanism may enable services even if they are not
requested - delegation may only be provided at the explicit request
of the application.
3.2. Mutual Authentication
Usually, a context acceptor will require that a context initiator
authenticate itself so that the acceptor may make an access-control
decision prior to performing a service for the initiator. In some
cases, the initiator may also request that the acceptor authenticate
itself. GSS-API allows the initiating application to request this
mutual authentication service by calling the requestMutualAuth method
of the GSSContext class with a "true" parameter before making the
first call to init. The initiating application is informed as to
whether or not the context acceptor has authenticated itself. Note
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that some mechanisms may not support mutual authentication, and other
mechanisms may always perform mutual authentication, whether or not
the initiating application requests it. In particular, mutual
authentication may be required by some mechanisms in order to support
replay or out-of-sequence message detection, and for such mechanisms
a request for either of these services will automatically enable
mutual authentication.
3.3. Replay and Out-of-Sequence Detection
The GSS-API may provide detection of mis-ordered messages once a
security context has been established. Protection may be applied to
messages by either application, by calling either getMIC or wrap
methods of the GSSContext class, and verified by the peer application
by calling verifyMIC or unwrap for the peer's GSSContext object.
The getMIC method calculates a cryptographic checksum of an
application message, and returns that checksum in a token. The
application should pass both the token and the message to the peer
application, which presents them to the verifyMIC method of the
peer's GSSContext object.
The wrap method calculates a cryptographic checksum of an application
message, and places both the checksum and the message inside a single
token. The application should pass the token to the peer
application, which presents it to the unwrap method of the peer's
GSSContext object to extract the message and verify the checksum.
Either pair of routines may be capable of detecting out-of-sequence
message delivery, or duplication of messages. Details of such mis-
ordered messages are indicated through supplementary query methods of
the MessageProp object that is filled in by each of these routines.
A mechanism need not maintain a list of all tokens that have been
processed in order to support these status codes. A typical
mechanism might retain information about only the most recent "N"
tokens processed, allowing it to distinguish duplicates and missing
tokens within the most recent "N" messages; the receipt of a token
older than the most recent "N" would result in the isOldToken method
of the instance of MessageProp to return "true".
3.4. Anonymous Authentication
In certain situations, an application may wish to initiate the
authentication process to authenticate a peer, without revealing its
own identity. As an example, consider an application providing
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access to a database containing medical information, and offering
unrestricted access to the service. A client of such a service might
wish to authenticate the service (in order to establish trust in any
information retrieved from it), but might not wish the service to be
able to obtain the client's identity (perhaps due to privacy concerns
about the specific inquiries, or perhaps simply to avoid being placed
on mailing-lists).
In normal use of the GSS-API, the initiator's identity is made
available to the acceptor as a result of the context establishment
process. However, context initiators may request that their identity
not be revealed to the context acceptor. Many mechanisms do not
support anonymous authentication, and for such mechanisms the request
will not be honored. An authentication token will still be
generated, but the application is always informed if a requested
service is unavailable, and has the option to abort context
establishment if anonymity is valued above the other security
services that would require a context to be established.
In addition to informing the application that a context is
established anonymously (via the isAnonymous method of the GSSContext
class), the getSrcName method of the acceptor's GSSContext object
will, for such contexts, return a reserved internal-form name,
defined by the implementation.
The toString method for a GSSName object representing an anonymous
entity will return a printable name. (Please note that for the
purposes of this discussion GSSName and IGSSName are used
interchangeably.) The returned value will be syntactically
distinguishable from any valid principal name supported by the
implementation. The associated name-type object identifier will be
an oid representing the value of NT_ANONYMOUS. This name-type oid
will be defined as a public, static Oid object of the GSSName class.
The printable form of an anonymous name should be chosen such that it
implies anonymity, since this name may appear in, for example, audit
logs. For example, the string "<anonymous>" might be a good choice,
if no valid printable names supported by the implementation can begin
with "<" and end with ">".
When using the equal method of the GSSName class, and one of the
operands is a GSSName instance representing an anonymous entity, the
method must return "false".
3.5. Confidentiality
If a GSSContext supports the confidentiality service, wrap method may
be used to encrypt application messages. Messages are selectively
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encrypted, under the control of the setPrivacy method of the
MessageProp object used in the wrap method.
3.6. Inter-process Context Transfer
GSS-API V2 provides functionality which allows a security context to
be transferred between processes on a single machine. These are
implemented using the export method of GSSContext and a byte array
constructor of the same class. The most common use for such a
feature is a client-server design where the server is implemented as
a single process that accepts incoming security contexts, which then
launches child processes to deal with the data on these contexts. In
such a design, the child processes must have access to the security
context object created within the parent so that they can use per-
message protection services and delete the security context when the
communication session ends.
Since the security context data structure is expected to contain
sequencing information, it is impractical in general to share a
context between processes. Thus GSSContext class provides an export
method that the process, which currently owns the context, can call
to declare that it has no intention to use the context subsequently,
and to create an inter-process token containing information needed by
the adopting process to successfully re-create the context. After
successful completion of export, the original security context is
made inaccessible to the calling process by GSS-API and any further
usage of this object will result in failures. The originating
process transfers the inter-process token to the adopting process,
which creates a new GSSContext object using the byte array
constructor. The properties of the context are equivalent to that of
the original context.
The inter-process token may contain sensitive data from the original
security context (including cryptographic keys). Applications using
inter-process tokens to transfer security contexts must take
appropriate steps to protect these tokens in transit.
Implementations are not required to support the inter-process
transfer of security contexts. Calling the isTransferable method of
the GSSContext class will indicate if the context object is
transferable.
3.7. The Use of Incomplete Contexts
Some mechanisms may allow the per-message services to be used before
the context establishment process is complete. For example, a
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mechanism may include sufficient information in its initial context-
level tokens for the context acceptor to immediately decode messages
protected with wrap or getMIC. For such a mechanism, the initiating
application need not wait until subsequent context-level tokens have
been sent and received before invoking the per-message protection
services.
An application can invoke the isProtReady method of the GSSContext
class to determine if the per-message services are available in
advance of complete context establishment. Applications wishing to
use per-message protection services on partially-established contexts
should query this method before attempting to invoke wrap or getMIC.
4. Calling Conventions
Java provides the implementors with not just a syntax for the
language, but also an operational environment. For example, memory
is automatically managed and does not require application
intervention. These language features have allowed for a simpler API
and have led to the elimination of certain GSS-API functions.
Moreover, the Java security libraries contain a provider architecture
that allows applications to be independent of the implementations of
the security API's they use. Using this model, applications can
seamlessly switch between different implementations at runtime in
order to get support for different mechanisms.
4.1. Package Name
The classes and interfaces defined in this document reside in the
package called "org.ietf.JGSS". Applications that wish to make use
of this API should import this package name as shows in section 8.
GSS-API implementors will have their implementation specific classes
that are not defined in this document reside in other packages. The
GSSManager class insulates the user from knowledge of these provider
specific packages.
4.2. Provider Framework
The Java security API's use a provider architecture that allows
applications to be implementation independent. The
java.security.Provider class is an abstract class that a vendor
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extends. This class maps various properties that represent different
security services to the names of the actual vendor classes that
implement those services. When requesting a service, an application
simply specifies the desired provider and the API classes delegate
the request to the appropriate provider class.
Providers of the Java GSS-API should map the property
"org.ietf.JGSS.GSSFactory" to the fully qualified name of their
implementation of the GSSFactory class. As explained later in
section 4.1 this class is the bootstrapping class for every GSS
provider and will allow the framework to obtain references to the
other classes that encapsulate the GSS services.
Using the Java security provider model insulates applications from
implementation details of the providers they wish to use. The
benefits of this approach are that applications can switch between
providers transparently and new providers can be added as needed.
Binary compatibility is maintained and applications can switch
providers even at runtime. The providers themselves can change
their implementation without having existing applications break.
4.3. Integer types
All numeric values are declared as "int" primitive Java type. The
Java specification guarantees that this will be a 32 bit two's
complement signed number.
Throughout this API, the "boolean" primitive Java type is used
wherever a boolean value is required or returned.
4.4. Opaque Data types
Java byte arrays are used to represent opaque data types which are
consumed and produced by the GSS-API in the forms of tokens. Java
arrays contain a length field which enables the users to easily
determine their size. The language has automatic garbage collection
which alleviates the need by developers to release memory and
simplifies buffer ownership issues.
4.5. Strings
The String object will be used to represent all textual data. The
Java String object, transparently treats all characters as two-byte
Unicode characters which allows support for many locals. All
routines returning or accepting textual data will use the String
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object.
4.6. Object Identifiers
An Oid object will be used to represent Universal Object Identifiers
(Oids). Oids are ISO-defined, hierarchically globally-interpretable
identifiers used within the GSS-API framework to identify security
mechanisms and name formats. The Oid object can be created from a
string representation of its dot notation (e.g. "1.3.6.1.5.6.2") as
well as from its ASN.1 DER encoding. Methods are also provided to
test equality and provide the DER representation for the object.
An important feature of the Oid class is that its instances are
immutable - i.e. there are no methods defined that allow one to
change the contents of an Oid. This property allows one to treat
these objects as "statics" without the need to perform copies.
Certain routines allow the usage of a default oid. A "null" value
can be used in those cases.
4.7. Object Identifier Sets
The Java bindings represents object identifiers sets as arrays of Oid
objects. All Java arrays contain a length field which allows for
easy manipulation and reference.
In order to support the full functionality of RFC 2078, the Oid class
includes a method which checks for existence of an Oid object within
a specified array. This is equivalent in functionality to
gss_test_oid_set_member. The use of Java arrays and Java's automatic
garbage collection has eliminated the need for the following
routines: gss_create_empty_oid_set, gss_release_oid_set, and
gss_add_oid_set_member. Java GSS-API implementations will not
contain them. Java's automatic garbage collection and the immutable
property of the Oid object eliminates the complicated memory
management issues of the C counterpart.
When ever a default value for an Object Identifier Set is required, a
"null" value can be used. Please consult the detailed method
description for details.
4.8. Credentials
GSS-API credentials are represented by the GSSCredential interface.
The interface contains several constructs to allow for the creation
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of most common credential objects for the initiator and the acceptor.
Comparisons are performed using the interface's "equals" method. The
following general description of GSS-API credentials is included from
the C-bindings specification:
GSS-API credentials can contain mechanism-specific principal
authentication data for multiple mechanisms. A GSS-API credential is
composed of a set of credential-elements, each of which is applicable
to a single mechanism. A credential may contain at most one
credential-element for each supported mechanism. A credential-
element identifies the data needed by a single mechanism to
authenticate a single principal, and conceptually contains two
credential-references that describe the actual mechanism-specific
authentication data, one to be used by GSS-API for initiating
contexts, and one to be used for accepting contexts. For mechanisms
that do not distinguish between acceptor and initiator credentials,
both references would point to the same underlying mechanism-specific
authentication data.
Credentials describe a set of mechanism-specific principals, and give
their holder the ability to act as any of those principals. All
principal identities asserted by a single GSS-API credential should
belong to the same entity, although enforcement of this property is
an implementation-specific matter. A single IGSSCredential object
represents all the credential elements that have been acquired.
The creation's of an IGSSContext object allows the value of "null" to
be specified as the IGSSCredential input parameter. This will
indicate a desire by the application to act as a default principal.
While individual GSS-API implementations are free to determine such
default behavior as appropriate to the mechanism, the following
default behavior by these routines is recommended for portability:
For the initiator side of the context:
1) If there is only a single principal capable of initiating
security contexts for the chosen mechanism that the
application is authorized to act on behalf of, then that
principal shall be used, otherwise
2) If the platform maintains a concept of a default network-
identity for the chosen mechanism, and if the application
is authorized to act on behalf of that identity for the
purpose of initiating security contexts, then the principal
corresponding to that identity shall be used, otherwise
3) If the platform maintains a concept of a default local
identity, and provides a means to map local identities into
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network-identities for the chosen mechanism, and if the
application is authorized to act on behalf of the network-
identity image of the default local identity for the
purpose of initiating security contexts using the chosen
mechanism, then the principal corresponding to that
identity shall be used, otherwise
4) A user-configurable default identity should be used.
and for the acceptor side of the context
1) If there is only a single authorized principal identity
capable of accepting security contexts for the chosen
mechanism, then that principal shall be used, otherwise
2) If the mechanism can determine the identity of the target
principal by examining the context-establishment token
processed during the accept method, and if the accepting
application is authorized to act as that principal for the
purpose of accepting security contexts using the chosen
mechanism, then that principal identity shall be used,
otherwise
3) If the mechanism supports context acceptance by any
principal, and if mutual authentication was not requested,
any principal that the application is authorized to accept
security contexts under using the chosen mechanism may be
used, otherwise
4) A user-configurable default identity shall be used.
The purpose of the above rules is to allow security contexts to be
established by both initiator and acceptor using the default behavior
whenever possible. Applications requesting default behavior are
likely to be more portable across mechanisms and implementations than
ones that instantiate an IGSSCredential object representing a
specific identity.
4.9. Contexts
The IGSSContext interface is used to represent one end of a GSS-API
security context, storing state information appropriate to that end
of the peer communication, including cryptographic state information.
The instantiation of the context object is done differently by the
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initiator and the acceptor. After the context has been instantiated,
the initiator may choose to set various context options which will
determine the characteristics of the desired security context. When
all the application desired characteristics have been set, the
initiator will call the initSecContext method which will produce a
token for consumption by the peer's acceptSecContext method. It is
the responsibility of the application to deliver the authentication
token(s) between the peer applications for processing. Upon
completion of the context establishment phase, context attributes can
be retrieved, by both the initiator and acceptor, using the accessor
methods. These will reflect the actual attributes of the established
context. At this point the context can be used by the application to
apply cryptographic services to its data.
4.10. Authentication tokens
A token is a caller-opaque type that GSS-API uses to maintain
synchronization between each end of the GSS-API security context.
The token is a cryptographically protected octet-string, generated by
the underlying mechanism at one end of a GSS-API security context for
use by the peer mechanism at the other end. Encapsulation (if
required) within the application protocol and transfer of the token
are the responsibility of the peer applications.
Java GSS-API uses byte arrays to represent authentication tokens.
Overloaded methods exist which allow the caller to supply input and
output streams which will be used for the reading and writing of the
token data.
4.11. Interprocess tokens
Certain GSS-API routines are intended to transfer data between
processes in multi-process programs. These routines use a caller-
opaque octet-string, generated by the GSS-API in one process for use
by the GSS-API in another process. The calling application is
responsible for transferring such tokens between processes. Note
that, while GSS-API implementors are encouraged to avoid placing
sensitive information within interprocess tokens, or to
cryptographically protect them, many implementations will be unable
to avoid placing key material or other sensitive data within them.
It is the application's responsibility to ensure that interprocess
tokens are protected in transit, and transferred only to processes
that are trustworthy. An interprocess token is represented using a
byte array emitted from the export method of the IGSSContext
interface. The receiver of the interprocess token would use
initialize an IGSSContext object with this token to create a new
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context. Once a context has been exported, the IGSSContext object is
invalidated and is no longer available.
4.12. Error Reporting
RFC 2078 defined the usage of major and minor status values for
signaling of GSS-API errors. The major code, also called GSS status
code, is used to signal errors at the GSS-API level independent of
the underlying mechanism(s). The minor status value or Mechanism
status code, is a mechanism defined error value indicating a
mechanism specific error code.
Java GSS-API uses exceptions implemented by the GSSException class to
signal both minor and major error values. Both, mechanism specific
errors and GSS-API level errors are signaled through instances of
this class. The usage of exceptions replaces the need for major and
minor codes to be used within the API calls. GSSException class also
contains methods to obtain textual representations for both the major
and minor values, which is equivalent to the functionality of
gss_display_status.
4.12.1. GSS status codes
GSS status codes indicate errors that are independent of the
underlying mechanism(s) used to provide the security service. The
errors that can be indicated via a GSS status code are generic API
routine errors (errors that are defined in the GSS-API
specification). These bindings take advantage of the Java exceptions
mechanism, thus eliminating the need for calling errors.
A GSS status code indicates a single fatal generic API error from the
routine that has thrown the GSSException. Using exceptions announces
that a fatal error has occurred during the execution of the method.
Two GSS-API routines can also return supplementary status information
which indicates non-fatal errors. These are handled as return values
since using exceptions is not appropriate for informatory or
warning-like information. The methods that are capable of producing
supplementary information are the two per-message methods
IGSSContext.verifyMIC() and IGSSContext.unwrap(). These methods fill
the supplementary status codes in the MessageProp object that was
passed in.
GSSException object, along with providing the functionality for
setting of the various error codes and translating them into textual
representation, also contains the definitions of all the numeric
error values. The following table lists the definitions of error
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codes:
Table: GSS Status Codes
Name Value Meaning
BAD_MECH 1 An unsupported mechanism
was requested.
BAD_NAME 2 An invalid name was supplied.
BAD_NAMETYPE 3 A supplied name was of an
unsupported type.
BAD_BINDINGS 4 Incorrect channel bindings were
supplied.
BAD_STATUS 5 An invalid status code was
supplied.
BAD_MIC 6 A token had an invalid MIC.
NO_CRED 7 No credentials were supplied, or
the credentials were unavailable
or inaccessible.
NO_CONTEXT 8 Invalid context has been
supplied.
DEFECTIVE_TOKEN 9 A supplied token was invalid.
DEFECTIVE_CREDENTIAL 10 A supplied credential was
invalid.
CREDENTIALS_EXPIRED 11 The referenced credentials
have expired.
CONTEXT_EXPIRED 12 The context has expired.
FAILURE 13 Miscellaneous failure,
unspecified at the GSS-API level.
BAD_QOP 14 The quality-of-protection
requested could not be provided.
UNAUTHORIZED 15 The operation is forbidden by
local security policy.
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UNAVAILABLE 16 The operation or option is
unavailable.
DUPLICATE_ELEMENT 17 The requested credential
element already exists.
NAME_NOT_MN 18 The provided name was not a
mechanism name.
OLD_TOKEN 19 The token's validity period has
expired.
DUPLICATE_TOKEN 20 The token was a duplicate of an
earlier version.
The GSS major status code of FAILURE is used to indicate that the
underlying mechanism detected an error for which no specific GSS
status code is defined. The mechanism-specific status code can
provide more details about the error.
4.12.2. Mechanism-specific status codes
The GSSException thrown from a GSS-API method may originate from the
mechanism independent layer or the mechanism specific layer. In the
latter case, the exception will be used to indicate not only the
major error codes but also the mechanism specific error code.
A default value of 0 will be used to represent the absence of the
mechanism specific status code.
4.12.3. Supplementary status codes
Supplementary status codes are confined to the per-message methods of
the IGSSContext interface. Because of the informative nature of
these errors it is not appropriate to use exceptions to signal them.
Instead, the per-message operations of the IGSSContext interface
return these values in a MessageProp object.
The MessageProp class defines query methods which return boolean
values indicating the following supplementary states:
Table: Supplementary Status Methods
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Method Name Meaning when "true" is returned
isDuplicateToken The token was a duplicate of an
earlier token.
isOldToken The token's validity period has
expired.
isUnseqToken A later token has already been
processed.
isGapToken An expected per-message token was
not received.
"true" return value for any of the above methods indicates that the
token exhibited the specified property. The application must
determine the appropriate course of action for these supplementary
values. They are not treated as errors by the GSS-API.
4.13. Names
A name is used to identify a person or entity. GSS-API authenticates
the relationship between a name and the entity claiming the name.
Since different authentication mechanisms may employ different
namespaces for identifying their principals, GSS-API's naming support
is necessarily complex in multi-mechanism environments (or even in
some single-mechanism environments where the underlying mechanism
supports multiple namespaces).
Two distinct conceptual representations are defined for names:
1) A GSS-API form represented by implementations of the IGSSName
interface: A single IGSSName object may contain multiple names
from different namespaces, but all names should refer to the
same entity. An example of such an internal name would be the
name returned from a call to the getName method of the
IGSSCredential interface, when applied to a credential
containing credential elements for multiple authentication
mechanisms employing different namespaces. This IGSSName object
will contain a distinct name for the entity for each
authentication mechanism.
For GSS-API implementations supporting multiple namespaces,
IGSSName implementations must contain sufficient information to
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determine the namespace to which each primitive name belongs.
2) Mechanism-specific contiguous byte array and string forms:
Different IGSSName initialization methods are provided to handle
both byte array and string formats and to accommodate various
calling applications and name types. These formats are capable
of containing only a single name (from a single namespace).
Contiguous string names are always accompanied by an object
identifier specifying the namespace to which the name belongs,
and their format is dependent on the authentication mechanism
that employs that name. The string name forms are assumed to be
printable, and may therefore be used by GSS-API applications for
communication with their users. The byte array name formats are
assumed to be in non-printable formats (e.g. the byte array
returned from the export method of the IGSSName interface).
An IGSSName object can be converted to a contiguous representation by
using the toString method. This will guarantee that the name will be
converted to a printable format. Different initialization methods in
the IGSSName interface are defined allowing support for multiple
syntaxes for each supported namespace, and allowing users the freedom
to choose a preferred name representation. The toString method
should use an implementation-chosen printable syntax for each
supported name-type. To obtain the printable name type,
getStringNameType method can be used.
There is no guarantee that calling the toString method on the
IGSSName interface will produce the same string form as the original
imported string name. Furthermore, it is possible that the name was
not even constructed from a string representation. The same applies
to name- space identifiers which may not necessarily survive
unchanged after a journey through the internal name-form. An example
of this might be a mechanism that authenticates X.500 names, but
provides an algorithmic mapping of Internet DNS names into X.500.
That mechanism's implementation of IGSSName might, when presented
with a DNS name, generate an internal name that contained both the
original DNS name and the equivalent X.500 name. Alternatively, it
might only store the X.500 name. In the latter case, the toString
method of IGSSName would most likely generate a printable X.500 name,
rather than the original DNS name.
The context acceptor can obtain an IGSSName object representing the
entity performing the context initiation (through the usage of
getSrcName method). Since this name has been authenticated by a
single mechanism, it contains only a single name (even if the
internal name presented by the context initiator to the IGSSContext
object had multiple components). Such names are termed internal
mechanism names, or "MN"s and the names emitted by IGSSContext
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interface in the getSrcName and getTargName are always of this type.
Since some applications may require MNs without wanting to incur the
overhead of an authentication operation, creation methods are
provided that take not only the name buffer and name type, but also
the mechanism oid for which this name should be created. When
dealing with an existing IGSSName object, the canonicalize method may
be invoked to convert a general internal name into an MN.
IGSSName objects can be compared using their equal method, which
returns "true" if the two names being compared refer to the same
entity. This is the preferred way to perform name comparisons
instead of using the printable names that a given GSS-API
implementation may support. Since GSS-API assumes that all primitive
names contained within a given internal name refer to the same
entity, equal can return "true" if the two names have at least one
primitive name in common. If the implementation embodies knowledge
of equivalence relationships between names taken from different
namespaces, this knowledge may also allow successful comparisons of
internal names containing no overlapping primitive elements.
When used in large access control lists, the overhead of creating an
IGSSName object on each name and invoking the equal method on each
name from the ACL may be prohibitive. As an alternative way of
supporting this case, GSS-API defines a special form of the
contiguous byte array name which may be compared directly (byte by
byte). Contiguous names suitable for comparison are generated by the
export method. Exported names may be re-imported by using the byte
array constructor and specifying the NT_EXPORT_NAME as the name type
object identifier. The resulting IGSSName name will also be a MN.
The IGSSName interface defines public static Oid objects representing
the standard name types. Structurally, an exported name object
consists of a header containing an OID identifying the mechanism that
authenticated the name, and a trailer containing the name itself,
where the syntax of the trailer is defined by the individual
mechanism specification. Detailed description of the format is
specified in the language-independent GSS-API specification
[GSSAPIv2].
Note that the results obtained by using the equals method will in
general be different from those obtained by invoking canonicalize and
export, and then comparing the byte array output. The first series
of operation determines whether two (unauthenticated) names identify
the same principal; the second whether a particular mechanism would
authenticate them as the same principal. These two operations will
in general give the same results only for MNs.
It is important to note that the above are guidelines as how IGSSName
implementations should behave, and are not intended to be specific
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requirements of how names objects must be implemented. The mechanism
designers are free to decide on the details of their implementations
of the IGSSName interface as long as the behavior satisfies the above
guidelines.
4.14. Channel Bindings
GSS-API supports the use of user-specified tags to identify a given
context to the peer application. These tags are intended to be used
to identify the particular communications channel that carries the
context. Channel bindings are communicated to the GSS-API using the
ChannelBinding object. The application may use byte arrays to
specify the application data to be used in the channel binding as
well as using instances of the InetAddress. The InetAddress for the
initiator and/or acceptor can be used within an instance of a
ChannelBinding. ChannelBinding can be set for the IGSSContext object
using the setChannelBinding method before the first call to init or
accept has been performed. Unless the setChannelBinding method has
been used to set the ChannelBinding for an IGSSContext object, "null"
ChannelBinding will be assumed. InetAddress is currently the only
address type defined within the Java platform and as such, it is the
only one supported within the ChannelBinding class. Applications
that use other types of addresses can include them as part of the
application specific data.
Conceptually, the GSS-API concatenates the initiator and acceptor
address information, and the application supplied byte array to form
an octet string. The mechanism calculates a MIC over this octet
string and binds the MIC to the context establishment token emitted
by init method of the IGSSContext class. The same bindings are set
by the context acceptor for its IGSSContext object and during
processing of the accept method a MIC is calculated in the same way.
The calculated MIC is compared with that found in the token, and if
the MICs differ, accept will throw a GSSException with the major
code set to BAD_BINDINGS, and the context will not be established.
Some mechanisms may include the actual channel binding data in the
token (rather than just a MIC); applications should therefore not use
confidential data as channel-binding components.
Individual mechanisms may impose additional constraints on addresses
that may appear in channel bindings. For example, a mechanism may
verify that the initiator address field of the channel binding
contains the correct network address of the host system. Portable
applications should therefore ensure that they either provide correct
information for the address fields, or omit setting of the addressing
information.
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4.15. Stream Objects
The context object provides overloaded methods which use input and
output streams as the means to convey authentication and per-message
GSS-API tokens. It is important to note that the streams are
expected to contain the usual GSS-API tokens which would otherwise be
handled through the usage of byte arrays. The tokens are expected to
have a definite start and an end. The callers are responsible for
ensuring that the supplied streams will not block, or expect to block
until a full token is processed by the GSS-API method. Only a single
GSS-API token will be processed per invocation of the stream based
method.
The usage of streams allows the callers to have control and
management of the supplied buffers. Because streams are non-
primitive objects, the callers can make the streams as complicated or
as simple as desired simply by using the streams defined in the
java.io package or creating their own through the use of inheritance.
This will allow for the application's greatest flexibility.
4.16. Optional Parameters
Whenever the application wishes to omit an optional parameter the
"null" value shall be used. The detailed method descriptions
indicate which parameters are optional. Methods overloading has also
been used as a technique to indicate default parameters.
5. GSS Provider's Interface
This section presents a brief description of the interfaces that
encapsulate the services provided by a GSS-API implementator. They
are part of a framework presented in this document that will allow an
application to switch between different providers at runtime, by
enabling the framework to access the desired provider's
implementation via these interfaces.
The API in this section is meant primarily for GSS implementors. The
GSS-API user does not need to obtain direct references to the classes
implementing these interfaces. In fact, doing so might make the
application dependent on that particular implementation.
Applications that distribute a bundled GSS-API implementation along
with them can use this API to avoid providing the concrete class
wrappers in the framework. However, for applications that expect to
use a system-wide GSS library, it is envisioned that the callers will
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utilize the wrapper classes of section 6 as the method of choice for
the creation of GSS-API objects.
This section also shows the corresponding RFC 2078 functionality
implemented by each of the interfaces. Detailed description of these
interfaces and their methods is presented in section 7.
5.1. GSSFactory interface
This interface represents the bootstrapping class that is supplied
with every GSS-API provider and encapsulates information that is
specific to that particular provider. It contains factory methods to
obtain references to implementations of the other interfaces from the
provider. GSSFactory also handles all queries which would require a
knowledge of the list of underlying mechanisms that is supported by
the particular provider. It contains equivalents of the following
RFC 2078 routines:
RFC 2078 Routine Function Section
gss_indicate_mechs List the mechanisms 7.1.10
supported by this GSS-API
implementation.
gss_inquire_mechs_for_name List the mechanisms 7.1.11
supporting the
specified name type.
gss_inquire_names_for_mech List the name types 7.1.12
supported by the
specified mechanism.
5.2. IGSSName interface
GSS-API names are represented in the Java bindings through the
IGSSName interface. Different name formats and their definitions are
identified with universal Object Identifiers (oids). The format of
the names can be derived based on the unique oid of each name type.
The following GSS-API routines are provided by the IGSSName
interface:
RFC 2078 Routine Function Section(s)
gss_import_name Create an internal name from 7.1.1-7.1.4
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the supplied information.
gss_display_name Covert internal name 7.2.6
representation to text format.
gss_compare_name Compare two internal names. 7.2.2, 7.2.3
gss_release_name Release resources associated N/A
with the internal name.
gss_canonicalize_name Convert an internal name to a 7.1.3, 7.2.4
mechanism name.
gss_export_name Convert a mechanism name to 7.2.5
export format.
gss_duplicate_name Create a copy of the internal N/A
name.
The gss_release_name call is not provided as Java does its own
garbage collection. The gss_duplicate_name call is also redundant;
the IGSSName interface has no mutator methods that can change the
state of the object, and so long as there is a reference to it, the
object will not be released by the JVM.
5.3. IGSSCredential interface
The IGSSCredential interface is responsible for the encapsulation of
GSS-API credentials. Credentials identify a single entity and
provide the necessary cryptographic information to enable the
creation of a context on behalf of that entity. A single credential
may contain multiple mechanism specific credentials, each referred to
as a credential element. The IGSSCredential interface provides the
functionality of the following GSS-API routines:
RFC 2078 Routine Function Section(s)
gss_acquire_cred Acquire credential for use. 7.1.5-7.1.7
gss_add_cred Constructs credentials 7.3.11
incrementally.
gss_inquire_cred Obtain information about 7.3.3-
credential.
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gss_inquire_cred_by_mech Obtain per-mechanism 7.3.3-7.3.10
information about
a credential.
gss_release_cred Disposes of credentials 7.3.2
after use.
5.4. IGSSContext interface
This interface encapsulates the functionality of context-level calls
required for security context establishment and management between
peers as well as the per-message services offered to applications. A
context is established between a pair of peers and allows the usage
of security services on a per-message basis on application data. It
is created over a single security mechanism. The IGSSContext
interface provides the functionality of the following GSS-API
routines:
RFC 2078 Routine Function Section(s)
gss_init_sec_context Initiate the creation of a 7.4.2,
security context with 7.4.3
a peer.
gss_accept_sec_context Accept a security context 7.4.4,
initiated by a peer. 7.4.5
gss_delete_sec_context Destroy a security context. 7.4.7
gss_context_time Obtain remaining context 7.4.36
time.
gss_inquire_context Obtain context 7.3.38 to
characteristics. 7.3.43
gss_wrap_size_limit Determine token-size limit 7.4.8
for gss_wrap.
gss_export_sec_context Transfer security context 7.4.17
to another process.
gss_import_sec_context Create a previously exported 7.1.10
context.
gss_get_mic Calculate a cryptographic 7.4.13,
Message Integrity Code (MIC) 7.4.14
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for a message.
gss_verify_mic Verify integrity on a received 7.4.15,
message. 7.4.16
gss_wrap Attach a MIC to a message and 7.4.9,
optionally encrypt the message 7.4.10
content.
gss_unwrap Obtain a previously wrapped 7.4.11,
application message verifying 7.4.12
its integrity and optionally
decrypting it.
The functionality offered by the gss_process_context_token routine
has not been included in the Java bindings specification. The
corresponding functionality of gss_delete_sec_context has also been
modified to not return any peer tokens. This has been proposed in
accordance to the recommendations stated in the RFC 2078 update
draft. IGSSContext does offer the functionality of destroying the
locally-stored context information.
6. GSS Application Programmer's Classes
This section presents a brief description of the classes that a
typical application would use. The implementations of these classes
are picked from the CLASSPATH defined by the application. If Java
GSS becomes part of the standard Java API's then these classes will
be available by default on all systems as part of the JRE's system
classes.
These classes are primarily part of a framework and do not provide
any of the security services themselves. The classes that provide
the security services are those that a provider can plug into this
framework as described in sections 4.2 and 5. Some classes described
here delegate their calls to the appropriate implementation class
from the provider.
This section also shows the corresponding RFC 2078 functionality
implemented by each of the interfaces. Detailed description of these
interfaces and their methods is presented in section 7.
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6.1. GSSManager class
This class contains methods to interrogate a provider's GSSFactory
object. It also provides a means for a single point of control to
set the preferred GSS-API provider. All delegation done by the
GSSContext, GSSCredential and GSSName classes is then directed to
implementing classes for that provider by default.
Implementions of this class can locate and instantiate a provider
with the help of the java.Security.getProvider() method. They can
query the provider for the "org.ietf.JGSS.GSSFactory" property which
returns the name of that provider's GSSFactory implementation.
By encapsulating this behaviour in this class an application can
seamlessly switch between GSS-API implementations at runtime by
simply identifying a new provider to the GSSManager.
It contains the equivalents of the following RFC 2078 routines to
query the provider's GSSFactory: gss_indicate_mechs,
gss_inquire_mechs_for_name, gss_inquire_names_for_mech.
6.2. GSSName class
This concrete class is a wrapper around the interface IGSSName. It
provides all the methods that are defined in the IGSSName interface
and associated constructors. It uses the preferred GSS-API provider
and its GSSFactory to instantiate an IGSSName implementation and then
delegate all calls to it.
6.3. GSSCredential class
This concrete class is a wrapper around the interface IGSSCredential.
It provides all the methods that are defined in the IGSSCredential
interface and associated constructors. It uses the preferred GSS-API
provider and its GSSFactory to instantiate an IGSSCredential
implementation and then delegate all calls to it.
6.4. GSSContext class
This concrete class is a wrapper around the interface IGSSContext.
It provides all the methods that are defined in the IGSSContext
interface and associated constructors. It uses the preferred GSS-API
provider and its GSSFactory to instantiate an IGSSContext
implementation and then delegate all calls to it.
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6.5. MessageProp class
This helper class is used in the per-message operations on the
context. An instance of this class is created by the application and
then passed into the per-message calls. In some cases, the
application conveys information to the GSS-API implementation through
this object and in other cases the GSS-API returns information to the
application by setting it in this object. See the description of the
per-message operations wrap, unwrap, getMIC, and verifyMIC in the
IGSSContext interfaces for details.
6.6. GSSException class
Exceptions are used in the Java bindings to signal fatal errors to
the calling applications. This replaces the major and minor codes
used in the C-bindings specification as a method of signaling
failures. The GSSException class handles both minor and major codes,
as well as their translation into textual representation. All GSS-
API methods are declared as throwing this exception.
RFC 2078 Routine Function Section
gss_display_status Retrieve textual 7.8.5, 7.8.6,
representation of error 7.8.8, 7.8.9
codes.
6.7. Oid class
This utility class is used to represent Universal Object Identifiers
and their associated operations. GSS-API uses object identifiers to
distinguish between security mechanisms and name types. This class,
aside from being used whenever an object identifier is needed,
implements the following GSS-API functionality:
RFC 2078 Routine Function Section
gss_test_oid_set_member Determine if the specified oid 7.7.6
is part of a set of oids.
6.8. ChannelBinding class
An instance of this class is used to specify channel binding
information to the IGSSContext object before the start of a security
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context establishment. The application may use a byte array to
specify application data to be used in the channel binding as well as
use instances of the InetAddress. InetAddress is currently the only
address type defined within the Java platform and as such, it is the
only one supported within the ChannelBinding class. Applications that
use other types of addresses can include them as part of the
application data.
7. Detailed GSS-API Class Description
This section lists a detailed description of all the public methods
that each of the GSS-API classes and interfaces must provide.
7.1. public interface GSSFactory
This interface provides factory methods to obtain provider specific
implementations of the interfaces IGSSCredential, IGSSName, and
IGSSContext. It also contains other functionality that requires
implementation specific knowledge and cannot be placed cleanly in any
of the other interfaces.
Each GSS-API provider defines a class that implements this interface.
Applications can instantiate the provider's implementation of
GSSFactory if they are aware of the qualified name of that class.
However, in the interest of portability applications are advised to
go through the GSSManager API instead. The GSSFactory interface is
primarily meant for GSS implementors and for developers who bundle a
custom GSS-API implementation together with their application. Such
applications may choose not to implement the GSSManager class along
with the other wrappers such as GSSName, GSSCredential, and
GSSContext. They would then directly instantiate and use the
interfaces described in section 5.
7.1.1. createName
public IGSSName createName(String nameStr, Oid nameSpace)
throws GSSException
Factory method to convert a contiguous string name from the specified
namespace to an IGSSName object. In general, the IGSSName object
created will not be an MN; two examples that are exceptions to this
are when the namespace type parameter indicates NT_EXPORT_NAME or
when the GSS-API implementation is not multi-mechanism.
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Parameters:
nameStr The string representing a printable form of the name
to create.
nameType The Oid specifying the namespace of the printable name
supplied. Note that nameType serves to describe and
qualify the interpretation of the input nameStr, it
does not necessarily imply a type for the output
IGSSName implementation. "null" value can be used to
specify that a mechanism specific default printable
syntax should be assumed by each mechanism that
examines nameStr.
7.1.2. createName
public IGSSName createName(byte name[], Oid nameType)
throws GSSException
Factory method to convert a contiguous byte array containing a name
from the specified namespace to an IGSSName object. In general, the
IGSSName object created will not be an MN; two examples that are
exceptions to this are when the namespace type parameter indicates
NT_EXPORT_NAME or when the GSS-API implementation is not multi-
mechanism.
Parameters:
name The byte array containing the name to create.
nameType The Oid specifying the namespace of the name supplied
in the byte array.
Note that nameType serves to describe and qualify the
interpretation of the input name byte array, it does not
necessarily imply a type for the output IGSSName implementation.
"null" value can be used to specify that a mechanism specific
default syntax should be assumed by each mechanism that examines
the byte array..IP "nameType" 10 The Oid specifying the
namespace of the printable name supplied. Note that nameType
serves to describe and qualify the interpretation of the input
nameStr, it does not necessarily imply a type for the output
IGSSName implementation. "null" value can be used to specify
that a mechanism specific default printable syntax should be
assumed by each mechanism that examines nameStr.
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7.1.3. createName
public IGSSName createName(String nameStr, Oid nameType,
Oid mechType) throws GSSException
Factory method to convert a contiguous string name from the specified
namespace to an IGSSName object that is a mechanism name (MN). In
other words, this method is a utility that does the equivalent of two
steps: the createName described in 7.1.1 and then also the
IGSSName.canonicalize() described in 7.2.4.
Parameters:
nameStr The string representing a printable form of the name
to create.
nameType The Oid specifying the namespace of the printable name
supplied. Note that nameType serves to describe and
qualify the interpretation of the input nameStr, it
does not necessarily imply a type for the output
IGSSName implementation. "null" value can be used to
specify that a mechanism specific default printable
syntax should be assumed when the mechanism examines
nameStr.
mechType Oid specifying the mechanism for which this name
should be created.
7.1.4. createName
public createName(byte name[], Oid nameType, Oid mechType)
throws GSSException
Factory method to convert a contiguous byte array containing a name
from the specified namespace to an IGSSName object that is an MN. In
other words, this method is a utility that does the equivalent of two
steps: the createName described in 7.1.2 and then also the
IGSSName.canonicalize() described in 7.2.4.
Parameters:
name The byte array representing the name to create.
nameType The Oid specifying the namespace of the name supplied
in the byte array. Note that nameType serves to
describe and qualify the interpretation of the input
name byte array, it does not necessarily imply a type
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for the output IGSSName implementation. "null" value
can be used to specify that a mechanism specific
default syntax should be assumed by each mechanism
that examines the byte array.
mechType Oid specifying the mechanism for which this name
should be created.
7.1.5. createCredential
public IGSSCredential createCredential (int usage)
throws GSSException
Factory method for acquiring default credentials. This will cause
the GSS-API to use system specific defaults for the set of
mechanisms, name, and an INDEFINITE lifetime.
Parameters:
usage The intended usage for this credential object. The
value of this parameter must be one of:
IGSSCredential.ACCEPT_AND_INITIATE,
IGSSCredential.ACCEPT_ONLY,
IGSSCredential.INITIATE_ONLY
7.1.6. createCredential
public IGSSCredential createCredential (IGSSName aName,
int lifetime, Oid mechOid, int usage)
throws GSSException
Factory method for acquiring a single mechanism credential.
Parameters:
aName Name of the principal for whom this credential is to
be acquired. Use "null" to specify the default
principal.
lifetime The number of seconds that credentials should remain
valid. Use IGSSCredential.INDEFINITE to request that
the credentials have the maximum permitted lifetime.
mechOid The oid of the desired mechanism. Use "(Oid) null" to
request the default mechanism(s).
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usage The intended usage for this credential object. The
value of this parameter must be one of:
IGSSCredential.ACCEPT_AND_INITIATE,
IGSSCredential.ACCEPT_ONLY,
IGSSCredential.INITIATE_ONLY
7.1.7. createCredential
public IGSSCredential createCredential(IGSSName aName,
int lifetime, Oid mechs[], int usage)
throws GSSException
Factory method for acquiring credentials over a set of mechanisms.
Acquires credentials for each of the mechanisms specified in the
array called mechs. To determine the list of mechanisms' for which
the acquisition of credentials succeeded, the caller should use the
IGSSCredential.getMechs() method.
Parameters:
aName Name of the principal for whom this credential is to
be acquired. Use "null" to specify the default
principal.
lifetime The number of seconds that credentials should remain
valid. Use IGSSCredential.INDEFINITE to request that
the credentials have the maximum permitted lifetime.
mechOid The array of mechanisms over which the credential is
to be acquired. Use "(Oid[]) null" for requesting a
system specific default set of mechanisms.
usage The intended usage for this credential object. The
value of this parameter must be one of:
IGSSCredential.ACCEPT_AND_INITIATE,
IGSSCredential.ACCEPT_ONLY,
IGSSCredential.INITIATE_ONLY
7.1.8. createContext
public IGSSContext createContext(IGSSName peer, Oid mechOid,
IGSSCredential myCred, int lifetime)
throws GSSException
Factory method for creating a context on the initiator's side.
Context flags may be modified through the mutator methods prior to
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calling IGSSContext.initSecContext().
Parameters:
peer Name of the target peer.
mechOid Oid of the desired mechanism. Use "(Oid) null" to
request default mechanism.
myCred Credentials of the initiator. Use "null" to act as a
default initiator principal.
lifetime The request lifetime, in seconds, for the credential.
7.1.9. createContext
public IGSSContext createContext(IGSSCredential myCred)
throws GSSException
Factory method for creating a context on the acceptor' side. The
context's properties will be determined from the input token supplied
to the accept method.
Parameters:
myCred Credentials for the acceptor. Use "null" to act as a
default acceptor principal.
7.1.10. createContext
public IGSSContext createContext(byte [] interProcessToken)
throws GSSException
Factory method for creating a previously exported context. The
context properties will be determined from the input token and can't
be modified through the set methods.
Parameters:
interProcessToken
The token previously emitted from the export method.
7.1.11. getMechs
public Oid[] getMechs()
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Returns an array of Oid objects, one for each mechanism available
through this GSS-API implementation. A "null" value is returned when
no mechanism are available (an example of this would be when
mechanism are dynamically configured, and currently no mechanisms are
installed).
7.1.12. getMechsForName
public Oid[] getMechsForName(Oid nameType)
Returns an array of Oid objects, one for each mechanism that supports
the specific namespace type. "null" is returned when no mechanisms
are found to support the specified namespace type.
Parameters:
nameType The Oid object for the namespace type
7.1.13. getNamesForMech
public Oid[] getNamesForMech(Oid mech) throws GSSException
Returns the Oid's for the various types of namespaces that are
supported by the specified mechanism.
Parameters:
mech The Oid for the mechanism to query.
7.2. public interface IGSSName extends java.security.Principal
This interface encapsulates a single GSS-API principal entity.
Different name formats and their definitions are identified with
universal Object Identifiers (Oids). The format of the names can be
derived based on the unique oid of its namespace type.
This interface extends the java.security.Principal interface which
represents the more abstract notion of an entity in Java. With
IGSSName extending this standard java interface, we achieve a tighter
integration of GSS-API names with java objects. Applications may use
this to their benefit in instances where a GSS name can be passed as
a java security name, for instance, to a repository of principal
names.
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The java.security.Principal.getName() method of a class implementing
the IGSSName interface is expected to return the same String as the
toString() method would, which is the equivalent of the
gss_display_name() call.
7.2.1. Static Constants
public static final Oid NT_HOSTBASED_SERVICE
Oid indicating a host-based service name form. It is used to
represent services associated with host computers. This name form is
constructed using two elements, "service" and "hostname", as follows:
service@hostname
Values for the "service" element are registered with the IANA. It
represents the following value: { 1(iso), 3(org), 6(dod),
1(internet), 5(security), 6(nametypes), 2(gss-host-based-services) }
public static final Oid NT_USER_NAME
Name type to indicate a named user on a local system. It represents
the following value: { iso(1) member-body(2) United States(840)
mit(113554) infosys(1) gssapi(2) generic(1) user_name(1) }
public static final Oid NT_MACHINE_UID_NAME
Name type to indicate a numeric user identifier corresponding to a
user on a local system. (e.g. Uid). It represents the following
value: { iso(1) member-body(2) United States(840) mit(113554)
infosys(1) gssapi(2) generic(1) machine_uid_name(2) }
public static final Oid NT_STRING_UID_NAME
Name type to indicate a string of digits representing the numeric
user identifier of a user on a local system. It represents the
following value: { iso(1) member-body(2) United States(840)
mit(113554) infosys(1) gssapi(2) generic(1) string_uid_name(3) }
public static final Oid NT_ANONYMOUS
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Name type for representing an anonymous entity. It represents the
following value: { 1(iso), 3(org), 6(dod), 1(internet), 5(security),
6(nametypes), 3(gss-anonymous-name) }
public static final Oid NT_EXPORT_NAME
Name type used to indicate an exported name produced by the export
method. It represents the following value: { 1(iso), 3(org), 6(dod),
1(internet), 5(security), 6(nametypes), 4(gss-api-exported-name) }
7.2.2. equals
public boolean equals(IGSSName another) throws GSSException
Compares two IGSSName objects to determine whether they refer to the
same entity. This method may throw a GSSException when the names
cannot be compared. If either of the names represents an anonymous
entity, the method will return "false".
Parameters:
another GSSName object to compare with.
7.2.3. equals
public boolean equals(Object another)
A variation of the equals method described in 7.2.2 that is provided
to override the Object.equals() method that the implementing class
will inherit. The behaviour is exactly the same as that in 7.2.2
except that no GSSException is thrown; instead, false will be
returned in the situation where an error occurs.
Parameters:
another GSSName object to compare with.
7.2.4. canonicalize
public IGSSName canonicalize(Oid mechOid) throws GSSException
Creates a mechanism name (MN) from an arbitrary internal name. This
is equivalent to using the factory methods described in 7.1.3 or
7.1.4 that take the mechanism name as one of their parameters.
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Parameters:
mechOid The oid for the authentication mechanism for which the
canonical form of the name is requested.
7.2.5. export
public byte[] export() throws GSSException
Returns a canonical contiguous byte representation of a mechanism
name (MN), suitable for direct, byte by byte comparison by
authorization functions. If the name is not an MN, implementations
may throw a GSSException with the NAME_NOT_MN status code. If an
implementation chooses not to throw an exception, it should use some
system specific default mechanism to canonicalize the name and then
export it. The format of the header of the outputted buffer is
specified in RFC 2078.
7.2.6. toString
public String toString()
Returns a textual representation of the GSSName object. To retrieve
the printed name format, which determines the syntax of the returned
string, the getStringNameType method can be used.
7.2.7. getStringNameType
public Oid getStringNameType() throws GSSException
Returns the oid representing the type of name returned through the
toString method. Using this oid, the syntax of the printable name
can be determined.
7.2.8. isAnonymous
public boolean isAnonymous()
Tests if this name object represents an anonymous entity. Returns
"true" if this is an anonymous name.
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7.2.9. isMN
public boolean isMN()
Tests if this name object contains only one mechanism element and is
thus a mechanism name as defined by RFC 2078.
7.3. public interface IGSSCredential implements Cloneable
This interface encapsulates the GSS-API credentials for an entity. A
credential contains all the necessary cryptographic information to
enable the creation of a context on behalf of the entity that it
represents. It may contain multiple, distinct, mechanism specific
credential elements, each containing information for a specific
security mechanism, but all referring to the same entity.
A credential may be used to perform context initiation, acceptance,
or both.
GSS-API implementations must impose a local access-control policy on
callers to prevent unauthorized callers from acquiring credentials to
which they are not entitled. GSS-API credential creation is not
intended to provide a "login to the network" function, as such a
function would involve the creation of new credentials rather than
merely acquiring a handle to existing credentials. Such functions,
if required, should be defined in implementation-specific extensions
to the API.
If credential acquisition is time-consuming for a mechanism, the
mechanism may choose to delay the actual acquisition until the
credential is required (e.g. by IGSSContext). Such mechanism-
specific implementation decisions should be invisible to the calling
application; thus the query methods immediately following the
creation of a credential object must return valid credential data,
and may therefore incur the overhead of a deferred credential
acquisition.
Applications will create a credential object passing the desired
parameters. The application can then use the query methods to obtain
specific information about the instantiated credential object
(equivalent to the gss_inquire routines). When the credential is no
longer needed, the application should call the dispose (equivalent to
gss_release_cred) method to release any resources held by the
credential object and to destroy any cryptographically sensitive
information.
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Classes implementing this interface also implement the Cloneable
interface. This indicates the the class will support the clone()
method that will allow the creation of duplicate credentials. This
is useful when called just before the add() call to retain a copy of
the original credential.
7.3.1. Static Constants
public static final int INITIATE_AND_ACCEPT
Credential usage flag requesting that it be able to be used for both
context initiation and acceptance.
public static final int INITIATE_ONLY
Credential usage flag requesting that it be able to be used for
context initiation only.
public static final int ACCEPT_ONLY
Credential usage flag requesting that it be able to be used for
context acceptance only.
public static final int INDEFINITE
A lifetime constant representing indefinite credential lifetime.
This value must be set to the maximum integer value in Java -
Integer.MAX_VALUE.
7.3.2. dispose
public void dispose() throws GSSException
Releases any sensitive information that the IGSSCredential object may
be containing. Applications should call this method as soon as the
credential is no longer needed to minimize the time any sensitive
information is maintained.
7.3.3. getName
public IGSSName getName() throws GSSException
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Retrieves the name of the entity that the credential asserts.
7.3.4. getName
public IGSSName getName(Oid mechOID) throws GSSException
Retrieves a mechanism name of the entity that the credential asserts.
Equivalent to calling canonicalize() on the name returned by 7.3.3.
Parameters:
mechOID The mechanism for which information should be
returned.
7.3.5. getRemainingLifetime
public int getRemainingLifetime() throws GSSException
Returns the remaining lifetime in seconds for a credential. The
remaining lifetime is the minimum lifetime for any of the underlying
credential mechanisms. A return value of IGSSCredential.INDEFINITE
indicates that the credential does not expire. A return value of 0
indicates that the credential is already expired.
7.3.6. getRemainingInitLifetime
public int getRemainingInitLifetime(Oid mech) throws GSSException
Returns the remaining lifetime is seconds for the credential to
remain capable of initiating security contexts under the specified
mechanism. A return value of IGSSCredential.INDEFINITE indicates
that the credential does not expire for context initiation. A return
value of 0 indicates that the credential is already expired.
Parameters:
mechOID The mechanism for which information should be
returned.
7.3.7. getRemainingAcceptLifetime
public int getRemainingAcceptLifetime(Oid mech) throws GSSException
Returns the remaining lifetime is seconds for the credential to
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remain capable of accepting security contexts under the specified
mechanism. A return value of IGSSCredential.INDEFINITE indicates
that the credential does not expire for context acceptance. A return
value of 0 indicates that the credential is already expired.
Parameters:
mechOID The mechanism for which information should be
returned.
7.3.8. getUsage
public int getUsage() throws GSSException
Returns the credential usage flag. The return value will be one of
IGSSCredential.INITIATE_ONLY, IGSSCredential.ACCEPT_ONLY, or
IGSSCredential.INITIATE_AND_ACCEPT.
7.3.9. getUsage
public int getUsage(Oid mechOID) throws GSSException
Returns the credential usage flag for the specified credential
mechanism. The return value will be one of
IGSSCredential.INITIATE_ONLY, IGSSCredential.ACCEPT_ONLY, or
IGSSCredential.INITIATE_AND_ACCEPT.
Parameters:
mechOID The mechanism for which information should be
returned.
7.3.10. getMechs
public Oid[] getMechs() throws GSSException
Returns an array of mechanisms supported by this credential.
7.3.11. add
public void add(GSSName aName, int initLifetime, int acceptLifetime,
Oid mech, int usage) throws GSSException
Adds a mechanism specific credential-element to an existing
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credential. This method allows the construction of credentials one
mechanism at a time.
This routine is envisioned to be used mainly by context acceptors
during the creation of acceptance credentials which are to be used
with a variety of clients using different security mechanisms.
This routine adds the new credential element "in-place". To add the
element in a new credential, first call clone() to obtain a copy of
this credential, then call its add() method.
Parameters:
aName Name of the principal for whom this credential is to
be acquired. Use "null" to specify the default
principal.
initLifetime
The number of seconds that credentials should remain
valid for initiating of security contexts. Use
GSSCredential.INDEFINITE to request that the
credentials have the maximum permitted lifetime.
acceptLifetime
The number of seconds that credentials should remain
valid for accepting of security contexts. Use
GSSCredential.INDEFINITE to request that the
credentials have the maximum permitted lifetime.
mechOid The mechanisms over which the credential is to be
acquired.
usage The intended usage for this credential object. The
value of this parameter must be one of:
GSSCredential.ACCEPT_AND_INITIATE,
GSSCredential.ACCEPT_ONLY, GSSCredential.INITIATE_ONLY
7.3.12. equals
public boolean equals(Object another)
Tests if this IGSSCredential refers to the same entity as the
supplied object. The two credentials must be acquired over the same
mechanisms and must refer to the same principal. Returns "true" if
the two GSSCredentials refer to the same entity; "false" otherwise.
Parameters:
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another Another IGSSCredential object for comparison.
7.4. public interface IGSSContext
This interface encapsulates the GSS-API security context and provides
the security services (wrap, unwrap, getMIC, verifyMIC) that are
available over the context. Security contexts are established
between peers using locally acquired credentials. Multiple contexts
may exist simultaneously between a pair of peers, using the same or
different set of credentials. GSS-API functions in a manner
independent of the underlying transport protocol and depends on its
calling application to transport its tokens between peers.
Before the context establishment phase is initiated, the context
initiator may request specific characteristics desired of the
established context. These can be set using the set methods. After
the context is established, the caller can check the actual
characteristic and services offered by the context using the query
methods.
The context establishment phase begins with the first call to the
init method by the context initiator. During this phase the
initSecContext and acceptSecContext methods will produce GSS-API
authentication tokens which the calling application needs to send to
its peer. If an error occurs at any point, an exception will get
thrown and the code will start executing in a catch block. If not,
the normal flow of code continues and the application can make a call
to the isEstablished() method. If this method returns false it
indicates that a token is needed from its peer in order to continue
the context establishment phase. A return value of true signals that
the local end of the context is established. This may still require
that a token be sent to the peer, if one is produced by GSS-API.
During the context establishment phase, the isProtReady() method may
be called to determine if the context can be used for the per-message
operations. This allows applications to use per-message operations
on contexts which aren't fully established.
After the context has been established or the isProtReady() method
returns "true", the query routines can be invoked to determine the
actual characteristics and services of the established context. The
application can also start using the per-message methods of wrap and
getMIC to obtain cryptographic operations on application supplied
data.
When the context is no longer needed, the application should call
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dispose to release any system resources the context may be using.
7.4.1. Static Constants
public static final int INDEFINITE
A lifetime constant representing indefinite context lifetime. This
value must be set to the maximum integer value in Java -
Integer.MAX_VALUE.
7.4.2. initSecContext
public byte[] initSecContext(byte inputBuf[], int offset, int len)
throws GSSException
Called by the context initiator to start the context creation
process. This is equivalent to the stream based method except that
the token buffers are handled as byte arrays instead of using stream
objects. This method may return an output token which the
application will need to send to the peer for processing by the
accept call. "null" return value indicates that no token needs to be
sent to the peer. The application can call isEstablished() to
determine if the context establishment phase is complete for this
peer. A return value of "false" from isEstablished() indicates that
more tokens are expected to be supplied to the initSecContext()
method. Note that it is possible that the initSecContext() method
return a token for the peer, and isEstablished() return "true" also.
This indicates that the token needs to be sent to the peer, but the
local end of the context is now fully established.
Upon completion of the context establishment, the available context
options may be queried through the get methods.
Parameters:
inputBuf Token generated by the peer. This parameter is ignored
on the first call.
offset The offset within the inputBuf where the token begins.
len The length of the token within the inputBuf (starting
at the offset).
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7.4.2.1. Example Code
// Create a new IGSSContext implementation object.
// GSSContext wrapper implements interface IGSSContext.
IGSSContext context = new GSSContext(...);
byte []inTok = new byte[0];
try {
do {
byte[] outTok = context.initSecContext(inTok, 0,
inTok.length);
// send the token if present
if (outTok != null)
sendToken(outTok);
// check if we should expect more tokens
if (context.isEstablished())
break;
// another token expected from peer
inTok = readToken();
} while (true);
} catch (GSSException e) {
print("GSSAPI error: " + e.getMessage());
}
7.4.3. initSecContext
public int initSecContext(InputStream inStream,
OutputStream outStream) throws GSSException
Called by the context initiator to start the context creation
process. This is equivalent to the byte array based method. This
method may write an output token to the outStream, which the
application will need to send to the peer for processing by the
accept call. 0 bytes written to the output stream indicate that no
token needs to be sent to the peer. The application can call
isEstablished() to determine if the context establishment phase is
complete for this peer. A return value of "false" from isEstablished
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indicates that more tokens are expected to be supplied to the
initSecContext method. Note that it is possible that the
initSecContext() method return a token for the peer, and
isEstablished() return "true" also. This indicates that the token
needs to be sent to the peer, but the local end of the context is now
fully established.
The GSS-API authentication tokens contain a definitive start and end.
This method will attempt to read one of these tokens per invocation,
and may block on the stream if only part of the token is available.
Upon completion of the context establishment, the available context
options may be queried through the get methods.
Parameters:
inStream Contains the token generated by the peer. This
parameter is ignored on the first call.
outStream Output stream where the output token will be written.
During the final stage of context establishment, there
may be no bytes written.
7.4.3.1. Example Code
// Create a new IGSSContext implementation object.
// GSSContext wrapper implements interface IGSSContext.
IGSSContext context = new GSSContext(...);
// use standard java.io stream objects
ByteArrayOutputStream os = new ByteArrayOutputStream();
ByteArrayInputStream is = null;
try {
do {
context.init(is, os);
// send token if present
if (os.size() > 0)
sendToken(os);
// check if we should expect more tokens
if (context.isEstablished())
break;
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// another token expected from peer
is = recvToken();
} while (true);
} catch (GSSException e) {
print("GSSAPI error: " + e.getMessage());
}
7.4.4. acceptSecContext
public byte[] acceptSecContext(byte inTok[], int offset, int len)
throws GSSException
Called by the context acceptor upon receiving a token from the peer.
This call is equivalent to the stream based method except that the
token buffers are handled as byte arrays instead of using stream
objects.
This method may return an output token which the application will
need to send to the peer for further processing by the init call.
"null" return value indicates that no token needs to be sent to the
peer. The application can call isEstablished() to determine if the
context establishment phase is complete for this peer. A return
value of "false" from isEstablished() indicates that more tokens are
expected to be supplied to this method.
Note that it is possible that acceptSecContext() return a token for
the peer, and isEstablished() return "true" also. This indicates
that the token needs to be sent to the peer, but the local end of the
context is now fully established.
Upon completion of the context establishment, the available context
options may be queried through the get methods.
Parameters:
inTok Token generated by the peer.
offset The offset within the inTok where the token begins.
len The length of the token within the inTok (starting at
the offset).
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7.4.4.1. Example Code
// acquire server credentials
IGSSCredential server = new GSSCredential(...);
// create acceptor GSS-API context fromthe default provider
IGSSContext context = new GSSContext(server, null);
try {
do {
byte [] inTok = readToken();
byte []outTok = context.accept(inTok, 0,
inTok.length);
// possibly send token to peer
if (outTok != null)
sendToken(outTok);
// check if local context establishment is complete
if (context.isEstablished())
break;
} while (true);
} catch (GSSException e) {
print("GSS-API error: " + e.getMessage());
}
7.4.5. acceptSecContext
public void acceptSecContext(InputStream inStream,
OutputStream outStream) throws GSSException
Called by the context acceptor upon receiving a token from the peer.
This call is equivalent to the byte array method. It may write an
output token to the outStreamf, which the application will need to
send to the peer for processing by its initSecContext method. 0 bytes
written to the output stream indicate that no token needs to be sent
to the peer. The application can call isEstablished() to determine
if the context establishment phase is complete for this peer. A
return value of "false" from isEstablished() indicates that more
tokens are expected to be supplied to this method.
Note that it is possible that acceptSecContext() return a token for
the peer, and isEstablished() return "true" also. This indicates
that the token needs to be sent to the peer, but the local end of the
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context is now fully established.
The GSS-API authentication tokens contain a definitive start and end.
This method will attempt to read one of these tokens per invocation,
and may block on the stream if only part of the token is available.
Upon completion of the context establishment, the available context
options may be queried through the get methods.
Parameters:
inStream Contains the token generated by the peer.
outStream Output stream where the output token will be written.
During the final stage of context establishment, there
may be no bytes written.
7.4.5.1. Example Code
// acquire server credentials
IGSSCredential server = new GSSCredential(...);
// create acceptor GSS-API context fromthe default provider
IGSSContext context = new GSSContext(server, null);
// use standard java.io stream objects
ByteArrayOutputStream os = new ByteArrayOutputStream();
ByteArrayInputStream is = null;
try {
do {
is = recvToken();
context.acceptSecContext(is, os);
// possibly send token to peer
if (os.size() > 0)
sendToken(os);
// check if local context establishment is complete
if (context.isEstablished())
break;
} while (true);
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} catch (GSSException e) {
print("GSS-API error: " + e.getMessage());
}
7.4.6. isEstablished
public boolean isEstablished()
Used during context establishment to determine the state of the
context. Returns "true" if this is a fully established context on
the caller's side and no more tokens are needed from the peer.
Should be called after a call to initSecContext() or
acceptSecContext() when no GSSException is thrown.
7.4.7. dispose
public void dispose() throws GSSException
Releases any system resources and cryptographic information stored in
the context object. This will invalidate the context.
7.4.8. getWrapSizeLimit
public int getWrapSizeLimit(int qop, boolean confReq,
int maxTokenSize) throws GSSException
Returns the maximum message size that, if presented to the wrap
method with the same confReq and qop parameters, will result in an
output token containing no more than the maxTokenSize bytes.
This call is intended for use by applications that communicate over
protocols that impose a maximum message size. It enables the
application to fragment messages prior to applying protection.
GSS-API implementations are recommended but not required to detect
invalid QOP values when getWrapSizeLimit is called. This routine
guarantees only a maximum message size, not the availability of
specific QOP values for message protection.
Successful completion of this call does not guarantee that wrap will
be able to protect a message of the computed length, since this
ability may depend on the availability of system resources at the
time that wrap is called. However, if the implementation itself
imposes an upper limit on the length of messages that may be
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processed by wrap, the implementation should not return a value that
is greater than this length.
Parameters:
qop Indicates the level of protection wrap will be asked
to provide.
confReq Indicates if wrap will be asked to provide privacy
service.
maxTokenSize
The desired maximum size of the token emitted by wrap.
7.4.9. wrap
public byte[] wrap(byte inBuf[], int offset, int len,
MessageProp msgProp) throws GSSException
Applies per-message security services over the established security
context. The method will return a token with a cryptographic MIC and
may optionally encrypt the specified inBuf. This method is
equivalent in functionality to its stream counterpart. The returned
byte array will contain both the MIC and the message.
The MessageProp object is instantiated by the application and used to
specify a QOP value which selects cryptographic algorithms, and a
privacy service to optionally encrypt the message. The underlying
mechanism that is used in the call may not be able to provide the
privacy service. It sets the actual privacy service that it does
provide in this MessageProp object which the caller should then query
upon return. If the mechanism is not able to provide the requested
QOP, it throws a GSSException with the BAD_QOP code.
Since some application-level protocols may wish to use tokens emitted
by wrap to provide "secure framing", implementations should support
the wrapping of zero-length messages.
The application will be responsible for sending the token to the
peer.
Parameters:
inBuf Application data to be protected.
offset The offset within the inBuf where the data begins.
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len The length of the data within the inBuf (starting at
the offset).
msgProp Instance of MessageProp that is used by the
application to set the desired QOP and privacy state.
Set the desired QOP to 0 to request the default QOP.
Upon return from this method, this object will contain
the the actual privacy state that was applied to the
message by the underlying mechanism.
7.4.10. wrap
public void wrap(InputStream inStream, OutputStream outStream,
MessageProp msgProp) throws GSSException
Allows to apply per-message security services over the established
security context. The method will produce a token with a
cryptographic MIC and may optionally encrypt the message in inStream.
The outStream will contain both the MIC and the message.
The MessageProp object is instantiated by the application and used to
specify a QOP value which selects cryptographic algorithms, and a
privacy service to optionally encrypt the message. The underlying
mechanism that is used in the call may not be able to provide the
privacy service. It sets the actual privacy service that it does
provide in this MessageProp object which the caller should then query
upon return. If the mechanism is not able to provide the requested
QOP, it throws a GSSException with the BAD_QOP code.
Since some application-level protocols may wish to use tokens emitted
by wrap to provide "secure framing", implementations should support
the wrapping of zero-length messages.
The application will be responsible for sending the token to the
peer.
Parameters:
inStream Input stream containing the application data to be
protected.
outStream The output stream to write the protected message to.
The application is responsible for sending this to the
other peer for processing in its unwrap method.
msgProp Instance of MessageProp that is used by the
application to set the desired QOP and privacy state.
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Set the desired QOP to 0 to request the default QOP.
Upon return from this method, this object will contain
the the actual privacy state that was applied to the
message by the underlying mechanism.
7.4.11. unwrap
public byte [] unwrap(byte[] inBuf, int offset, int len,
MessageProp msgProp) throws GSSException
Used by the peer application to process tokens generated with the
wrap call. This call is equal in functionality to its stream
counterpart. The method will return the message supplied in the peer
application to the wrap call, verifying the embedded MIC.
The MessageProp object is instantiated by the application and is used
by the underlying mechanism to return information to the caller such
as the QOP, whether confidentiality was applied to the message, and
other supplementary message state information.
Since some application-level protocols may wish to use tokens emitted
by wrap to provide "secure framing", implementations should support
the wrapping and unwrapping of zero-length messages.
Parameters:
inBuf GSS-API wrap token received from peer.
offset The offset within the inBuf where the token begins.
len The length of the token within the inBuf (starting at
the offset).
msgProp Upon return from the method, this object will contain
the applied QOP, the privacy state of the message, and
supplementary information described in 4.12.3 stating
whether the token was a duplicate, old, out of
sequence or arriving after a gap.
7.4.12. unwrap
public void unwrap(InputStream inStream, OutputStream outStream,
MessageProp msgProp) throws GSSException
Used by the peer application to process tokens generated with the
wrap call. This call is equal in functionality to its byte array
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counterpart. It will produce the message supplied in the peer
application to the wrap call, verifying the embedded MIC.
The MessageProp object is instantiated by the application and is used
by the underlying mechanism to return information to the caller such
as the QOP, whether confidentiality was applied to the message, and
other supplementary message state information.
Since some application-level protocols may wish to use tokens emitted
by wrap to provide "secure framing", implementations should support
the wrapping and unwrapping of zero-length messages.
Parameters:
inStream Input stream containing the GSS-API wrap token
received from the peer.
outStream The output stream to write the application message to.
msgProp Upon return from the method, this object will contain
the applied QOP, the privacy state of the message, and
supplementary information described in 4.12.3 stating
whether the token was a duplicate, old, out of
sequence or arriving after a gap.
7.4.13. getMIC
public byte[] getMIC(byte []inMsg, int offset, int len,
MessageProp msgProp) throws GSSException
Returns a token containing a cryptographic MIC for the supplied
message, for transfer to the peer application. Unlike wrap, which
encapsulates the user message in the returned token, only the message
MIC is returned in the output token. This method is identical in
functionality to its stream counterpart.
Note that privacy can only be applied through the wrap call.
Since some application-level protocols may wish to use tokens emitted
by getMIC to provide "secure framing", implementations should support
derivation of MICs from zero-length messages.
Parameters:
inMsg Message to generate MIC over.
offset The offset within the inMsg where the token begins.
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len The length of the token within the inMsg (starting at
the offset).
msgProp Instance of MessageProp that is used by the
application to set the desired QOP. Set the desired
QOP to 0 in msgProp to request the default QOP.
Alternatively pass in "null" for msgProp to request
default QOP.
7.4.14. getMIC
public void getMIC(InputStream inStream, OutputStream outStream,
MessageProp msgProp) throws GSSException
Produces a token containing a cryptographic MIC for the supplied
message, for transfer to the peer application. Unlike wrap, which
encapsulates the user message in the returned token, only the message
MIC is produced in the output token. This method is identical in
functionality to its byte array counterpart.
Note that privacy can only be applied through the wrap call.
Since some application-level protocols may wish to use tokens emitted
by getMIC to provide "secure framing", implementations should support
derivation of MICs from zero-length messages.
Parameters:
inStream inStream Input stream containing the message to
generate MIC over.
outStream outStream Output stream to write the GSS-API output
token to.
msgProp Instance of MessageProp that is used by the
application to set the desired QOP. Set the desired
QOP to 0 in msgProp to request the default QOP.
Alternatively pass in "null" for msgProp to request
default QOP.
7.4.15. verifyMIC
public void verifyMIC(byte []inTok, int tokOffset, int tokLen,
byte[] inMsg, int msgOffset, int msgLen,
MessageProp msgProp) throws GSSException
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Verifies the cryptographic MIC, contained in the token parameter,
over the supplied message. This method is equivalent in
functionality to its stream counterpart.
The MessageProp object is instantiated by the application and is used
by the underlying mechanism to return information to the caller such
as the QOP indicating the strength of protection that was applied to
the message and other supplementary message state information.
Since some application-level protocols may wish to use tokens emitted
by getMIC to provide "secure framing", implementations should support
the calculation and verification of MICs over zero-length messages.
Parameters:
inTok Token generated by peer's getMIC method.
tokOffset The offset within the inTok where the token begins.
tokLen The length of the token within the inTok (starting at
the offset).
inMsg Application message to verify the cryptographic MIC
over.
msgOffset The offset within the inMsg where the message begins.
msgLen The length of the message within the inMsg (starting
at the offset).
msgProp Upon return from the method, this object will contain
the applied QOP and supplementary information
described in 4.12.3 stating whether the token was a
duplicate, old, out of sequence or arriving after a
gap. The confidentiality state will be set to
"false".
7.4.16. verifyMIC
public void verifyMIC(InputStream tokStream, InputStream msgStream,
MessageProp msgProp) throws GSSException
Verifies the cryptographic MIC, contained in the token parameter,
over the supplied message. This method is equivalent in
functionality to its byte array counterpart.
The MessageProp object is instantiated by the application and is used
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by the underlying mechanism to return information to the caller such
as the QOP indicating the strength of protection that was applied to
the message and other supplementary message state information.
Since some application-level protocols may wish to use tokens emitted
by getMIC to provide "secure framing", implementations should support
the calculation and verification of MICs over zero-length messages.
Parameters:
tokStream Input stream containing the token generated by peer's
getMIC method.
msgStream Input stream containing the application message to
verify the cryptographic MIC over.
msgProp Upon return from the method, this object will contain
the applied QOP and supplementary information
described in 4.12.3 stating whether the token was a
duplicate, old, out of sequence or arriving after a
gap. The confidentiality state will be set to
"false".
7.4.17. export
public byte [] export() throws GSSException
Provided to support the sharing of work between multiple processes.
This routine will typically be used by the context-acceptor, in an
application where a single process receives incoming connection
requests and accepts security contexts over them, then passes the
established context to one or more other processes for message
exchange.
This method deactivates the security context and creates an
interprocess token which, when passed to the byte array constructor
of the GSSContext class in another process, will re-activate the
context in the second process. Only a single instantiation of a
given context may be active at any one time; a subsequent attempt by
a context exporter to access the exported security context will fail.
The implementation may constrain the set of processes by which the
interprocess token may be imported, either as a function of local
security policy, or as a result of implementation decisions. For
example, some implementations may constrain contexts to be passed
only between processes that run under the same account, or which are
part of the same process group.
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The interprocess token may contain security-sensitive information
(for example cryptographic keys). While mechanisms are encouraged to
either avoid placing such sensitive information within interprocess
tokens, or to encrypt the token before returning it to the
application, in a typical GSS-API implementation this may not be
possible. Thus the application must take care to protect the
interprocess token, and ensure that any process to which the token is
transferred is trustworthy.
7.4.18. requestMutualAuth
public void requestMutualAuth(boolean state) throws GSSException
Sets the request state of the mutual authentication flag for the
context. This method is only valid before the context creation
process begins and only for the initiator.
Parameters:
state Boolean representing if mutual authentication should
be requested during context establishment.
7.4.19. requestReplayDet
public void requestReplayDet(boolean state) throws GSSException
Sets the request state of the replay detection service for the
context. This method is only valid before the context creation
process begins and only for the initiator.
Parameters:
state Boolean representing if replay detection is desired
over the established context.
7.4.20. requestSequenceDet
public void requestSequenceDet(boolean state) throws GSSException
Sets the request state for the sequence checking service of the
context. This method is only valid before the context creation
process begins and only for the initiator.
Parameters:
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state Boolean representing if sequence detection is desired
over the established context.
7.4.21. requestCredDeleg
public void requestCredDeleg(boolean state) throws GSSException
Sets the request state for the credential delegation flag for the
context. This method is only valid before the context creation
process begins and only for the initiator.
Parameters:
state Boolean representing if credential delegation is
desired.
7.4.22. requestAnonymity
public void requestAnonymity(boolean state) throws GSSException
Requests anonymous support over the context. This method is only
valid before the context creation process begins and only for the
initiator.
Parameters:
state Boolean representing if anonymity support is
requested.
7.4.23. requestConf
public void requestConf(boolean state) throws GSSException
Requests that confidentiality service be available over the context.
This method is only valid before the context creation process begins
and only for the initiator.
Parameters:
state Boolean indicating if confidentiality services are to
be requested for the context.
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7.4.24. requestInteg
public void requestInteg(boolean state) throws GSSException
Requests that integrity services be available over the context. This
method is only valid before the context creation process begins and
only for the initiator.
Parameters:
state Boolean indicating if integrity services are to be
requested for the context.
7.4.25. requestLifetime
public void requestLifetime(int lifetime) throws GSSException
Sets the desired lifetime for the context in seconds. This method is
only valid before the context creation process begins and only for
the initiator.
Parameters:
lifetime The desired context lifetime in seconds.
7.4.26. setChannelBinding
public void setChannelBinding(ChannelBinding cb) throws GSSException
Sets the channel bindings to be used during context establishment.
This method is only valid before the context creation process begins.
Parameters:
cb Channel bindings to be used.
7.4.27. getCredDelegState
public boolean getCredDelegState()
Returns the state of the delegated credentials for the context. When
issued before context establishment is completed or when the
isProtReady method returns "false", it returns the desired state,
otherwise it will indicate the actual state over the established
context.
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7.4.28. getMutualAuthState
public boolean getMutualAuthState()
Returns the state of the mutual authentication option for the
context. When issued before context establishment completes or when
the isProtReady method returns "false", it returns the desired state,
otherwise it will indicate the actual state over the established
context.
7.4.29. getReplayDetState
public boolean getReplayDetState()
Returns the state of the replay detection option for the context.
When issued before context establishment completes or when the
isProtReady method returns "false", it returns the desired state,
otherwise it will indicate the actual state over the established
context.
7.4.30. getSequenceDetState
public boolean getSequenceDetState()
Returns the state of the sequence detection option for the context.
When issued before context establishment completes or when the
isProtReady method returns "false", it returns the desired state,
otherwise it will indicate the actual state over the established
context.
7.4.31. getAnonymityState
public boolean getAnonymityState()
Returns "true" if this is an anonymous context. When issued before
context establishment completes or when the isProtReady method
returns "false", it returns the desired state, otherwise it will
indicate the actual state over the established context.
7.4.32. isTransferable
public boolean isTransferable() throws GSSException
Returns "true" if the context is transferable to other processes
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through the use of the export method. This call is only valid on
fully established contexts.
7.4.33. isProtReady
public boolean isProtReady()
Returns "true" if the per message operations can be applied over the
context. Some mechanisms may allow the usage of per-message
operations before the context is fully established. This will also
indicate that the get methods will return actual context state
characteristics instead of the desired ones.
7.4.34. getConfState
public boolean getConfState()
Returns the confidentiality service state over the context. When
issued before context establishment completes or when the isProtReady
method returns "false", it returns the desired state, otherwise it
will indicate the actual state over the established context.
7.4.35. getIntegState
public boolean getIntegState()
Returns the integrity service state over the context. When issued
before context establishment completes or when the isProtReady method
returns "false", it returns the desired state, otherwise it will
indicate the actual state over the established context.
7.4.36. getLifetime
public int getLifetime()
Returns the context lifetime in seconds. When issued before context
establishment completes or when the isProtReady method returns
"false", it returns the desired lifetime, otherwise it will indicate
the remaining lifetime for the context.
7.4.37. getSrcName
public GSSName getSrcName() throws GSSException
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Returns the name of the context initiator. This call is valid only
after the context is fully established or the isProtReady method
returns "true". It is guaranteed to return an MN.
7.4.38. getTargName
public GSSName getTargName() throws GSSException
Returns the name of the context target (acceptor). This call is
valid only after the context is fully established or the isProtReady
method returns "true". It is guaranteed to return an MN.
7.4.39. getMech
public Oid getMech() throws GSSException
Returns the mechanism oid for this context.
7.4.40. getDelegCred
public GSSCredential getDelegCred() throws GSSException
Returns the delegated credential object on the acceptor's side. To
check for availability of delegated credentials call
getDelegCredState. This call is only valid on fully established
contexts.
7.4.41. isInitiator
public boolean isInitiator() throws GSSException
Returns "true" if this is the initiator of the context. This call is
only valid after the context creation process has started.
7.5. public class MessageProp
This is a utility class used within the per-message GSSContext
methods to convey per-message properties.
When used with the IGSSContext interface's wrap and getMIC methods,
an instance of this class is used to indicate the desired QOP and to
request if confidentiality services are to be applied to caller
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supplied data (wrap only). To request default QOP, the value of 0
should be used for QOP.
When used with the unwrap and verifyMIC methods of the IGSSContext
interface, an instance of this class will be used to indicate the
applied QOP and confidentiality services over the supplied message.
In the case of verifyMIC, the confidentiality state will always be
"false". Upon return from these methods, this object will also
contain any supplementary status values applicable to the processed
token. The supplementary status values can indicate old tokens, out
of sequence tokens, gap tokens or duplicate tokens.
7.5.1. Constructors
public MessageProp(boolean privState)
Constructor which sets QOP to 0 indicating that the default QOP is
requested.
Parameters:
privState The desired privacy state. "true" for privacy and
"false" for integrity only.
public MessageProp(int qop, boolean privState)
Constructor which sets the values for the qop and privacy state.
Parameters:
qop The desired QOP. Use 0 to request a default QOP.
privState The desired privacy state. "true" for privacy and
"false" for integrity only.
7.5.2. getQOP
public int getQOP()
Retrieves the QOP value.
7.5.3. getPrivacy
public boolean getPrivacy()
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Retrieves the privacy state.
7.5.4. setQOP
public void setQOP(int qopVal)
Sets the QOP value.
Parameters:
qopVal The QOP value to be set. Use 0 to request a default
QOP value.
7.5.5. setPrivacy
public void setPrivacy(boolean privState)
Sets the privacy state.
Parameters:
privState The privacy state to set.
7.5.6. isDuplicateToken
public boolean isDuplicateToken()
Returns "true" if this is a duplicate of an earlier token.
7.5.7. isOldToken
public boolean isOldToken()
Returns "true" if the token's validity period has expired.
7.5.8. isUnseqToken
public boolean isUnseqToken()
Returns "true" if a later token has already been processed.
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7.5.9. isGapToken
public boolean isGapToken()
Returns "true" if an expected per-message token was not received.
7.5.10. setSupplementaryStates
public void setSupplementaryStates(boolean duplicate,
boolean old, boolean unseq, boolean gap)
This method sets the state for the supplementary information flags in
MessageProp. It is not used by the application but by the GSS
implementation to return this information to the caller of a per-
message context method.
Parameters:
duplicate true if the token was a duplicate of an earlier token,
false otherwise
old true if the token's validity period has expired, false
otherwise
unseq true if a later token has already been processed,
false otherwise
gap true if one or more predecessor tokens have not yet
been succesfully processed, false otherwise
7.6. public class ChannelBinding
The GSS-API accommodates the concept of caller-provided channel
binding information. Channel bindings are used to strengthen the
quality with which peer entity authentication is provided during
context establishment. They enable the GSS-API callers to bind the
establishment of the security context to relevant characteristics
like addresses or to application specific data.
The caller initiating the security context must determine the
appropriate channel binding values to set in the GSSContext object.
The acceptor must provide an identical binding in order to validate
that received tokens possess correct channel-related characteristics.
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Use of channel bindings is optional in GSS-API. Since channel-
binding information may be transmitted in context establishment
tokens, applications should therefore not use confidential data as
channel-binding components.
7.6.1. Constructors
public ChannelBinding(InetAddress initAddr, InetAddress acceptAddr,
byte[] appData)
Create a ChannelBinding object with user supplied address information
and data. "null" values can be used for any fields which the
application does not want to specify.
Parameters:
initAddr The address of the context initiator. "null" value
can be supplied to indicate that the application does
not want to set this value.
acceptAddrThe address of the context acceptor. "null" value can
be supplied to indicate that the application does not
want to set this value.
appData Application supplied data to be used as part of the
channel bindings. "null" value can be supplied to
indicate that the application does not want to set
this value.
public ChannelBinding(byte[] appData)
Creates a ChannelBinding object without any addressing information.
Parameters:
appData Application supplied data to be used as part of the
channel bindings.
7.6.2. getInitiatorAddress
public InetAddress getInitiatorAddress()
Returns the initiator's address for this channel binding. "null" is
returned if the address has not been set.
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7.6.3. getAcceptorAddress
public InetAddress getAcceptorAddress()
Returns the acceptor's address for this channel binding. "null" is
returned if the address has not been set.
7.6.4. getApplicationData
public byte[] getApplicationData()
Returns application data being used as part of the ChannelBinding.
"null" is returned if no application data has been specified for the
channel binding.
7.6.5. equals
public boolean equals(Object obj)
Returns "true" if two channel bindings match.
Parameters:
obj Another channel binding to compare with.
7.7. public class Oid
This class represents Universal Object Identifiers (Oids) and their
associated operations.
Oids are hierarchically globally-interpretable identifiers used
within the GSS-API framework to identify mechanisms and name formats.
The structure and encoding of Oids is defined in ISOIEC-8824 and
ISOIEC-8825. For example the Oid representation of Kerberos V5
mechanism is "1.2.840.113554.1.2.2"
The GSSName name class contains public static Oid objects
representing the standard name types defined in GSS-API.
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7.7.1. Constructors
public Oid(String strOid) throws GSSException
Creates an Oid object from a string representation of its integer
components (e.g. "1.2.840.113554.1.2.2").
Parameters:
strOid The string representation for the oid.
public Oid(InputStream derOid) throws GSSException
Creates an Oid object from its DER encoding. This refers to the full
encoding including tag and length. The structure and encoding of
Oids is defined in ISOIEC-8824 and ISOIEC-8825. This method is
identical in functionality to its byte array counterpart.
Parameters:
derOid Stream containing the DER encoded oid.
public Oid(byte[] DEROid) throws GSSException
Creates an Oid object from its DER encoding. This refers to the full
encoding including tag and length. The structure and encoding of
Oids is defined in ISOIEC-8824 and ISOIEC-8825. This method is
identical in functionality to its byte array counterpart.
Parameters:
derOid Byte array storing a DER encoded oid.
7.7.2. toString
public String toString()
Returns a string representation of the oid's integer components in
dot separated notation (e.g. "1.2.840.113554.1.2.2").
7.7.3. equals
public boolean equals(Object Obj)
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Returns "true" if the two Oid objects represent the same oid value.
Parameters:
obj Another Oid object to compare with.
7.7.4. getDER
public byte[] getDER()
Returns the full ASN.1 DER encoding for this oid object, which
includes the tag and length.
7.7.5. containedIn
public boolean containedIn(Oid[] oids)
A utility method to test if an Oid object is contained within the
supplied Oid object array.
Parameters:
oids An array of oids to search.
7.8. public class GSSException extends Exception
This exception is thrown whenever a fatal GSS-API error occurs
including mechanism specific errors. It may contain both, the major
and minor, GSS-API status codes. The mechanism implementers are
responsible for setting appropriate minor status codes when throwing
this exception. Aside from delivering the numeric error code(s) to
the caller, this class performs the mapping from their numeric values
to textual representations. All Java GSS-API methods are declared
throwing this exception.
All implementations are encouraged to use the Java
internationalization techniques to provide local translations of the
message strings.
7.8.1. Static Constants
All valid major GSS-API error code values are declared as constants
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in this class.
public static final int BAD_BINDINGS
Channel bindings mismatch error.
public static final int BAD_MECH
Unsupported mechanism requested error.
public static final int BAD_NAME
Invalid name provided error.
public static final int BAD_NAMETYPE
Name of unsupported type provided error.
public static final int BAD_STATUS
Invalid status code error - this is the default status value.
public static final int BAD_MIC
Token had invalid integrity check error.
public static final int CONTEXT_EXPIRED
Specified security context expired error.
public static final int CREDENTIALS_EXPIRED
Expired credentials detected error.
public static final int DEFECTIVE_CREDENTIAL
Defective credential error.
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public static final int DEFECTIVE_TOKEN
Defective token error.
public static final int FAILURE
General failure, unspecified at GSS-API level.
public static final int NO_CONTEXT
Invalid security context error.
public static final int NO_CRED
Invalid credentials error.
public static final int BAD_QOP
Unsupported QOP value error.
public static final int UNAUTHORIZED
Operation unauthorized error.
public static final int UNAVAILABLE
Operation unavailable error.
public static final int DUPLICATE_ELEMENT
Duplicate credential element requested error.
public static final int NAME_NOT_MN
Name contains multi-mechanism elements error.
public static final int DUPLICATE_TOKEN
The token was a duplicate of an earlier token. This is a fatal error
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code that may occur during context establishment. It is not used to
indicate supplementary status values. The MessageProp object is used
for that purpose.
public static final int OLD_TOKEN
The token's validity period has expired. This is a fatal error code
that may occur during context establishment. It is not used to
indicate supplementary status values. The MessageProp object is used
for that purpose.
public static final int UNSEQ_TOKEN
A later token has already been processed. This is a fatal error code
that may occur during context establishment. It is not used to
indicate supplementary status values. The MessageProp object is used
for that purpose.
public static final int GAP_TOKEN
An expected per-message token was not received. This is a fatal
error code that may occur during context establishment. It is not
used to indicate supplementary status values. The MessageProp object
is used for that purpose.
7.8.2. Constructors
public GSSException(int majorCode)
Creates a GSSException object with a specified major code.
Parameters:
majorCode The GSS error code causing this exception to be
thrown.
public GSSException(int majorCode, int minorCode, String minorString)
Creates a GSSException object with the specified major code, minor
code, and minor code textual explanation. This constructor is to be
used when the exception is originating from the security mechanism.
It allows to specify the GSS code and the mechanism code.
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Parameters:
majorCode The GSS error code causing this exception to be
thrown.
minorCode The mechanism error code causing this exception
to be thrown.
minorString The textual explanation of the mechanism error
code.
7.8.3. getMajor
public int getMajor()
Returns the major code representing the GSS error code that caused
this exception to be thrown.
7.8.4. getMinor
public int getMinor()
Returns the mechanism error code that caused this exception. The
minor code is set by the underlying mechanism. Value of 0 indicates
that mechanism error code is not set.
7.8.5. getMajorString
public String getMajorString()
Returns a string explaining the GSS major error code causing this
exception to be thrown.
7.8.6. getMinorString
public String getMinorString()
Returns a string explaining the mechanism specific error code. An
empty string will be returned when no mechanism error code has been
set.
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7.8.7. setMinor
public void setMinor(int minorCode, String message)
Used internally by the GSS-API implementation and the underlying
mechanisms to set the minor code and its textual representation.
Parameters:
minorCode The mechanism specific error code.
message A textual explanation of the mechanism error code.
7.8.8. toString
public String toString()
Returns a textual representation of both the major and minor status
codes.
7.8.9. getMessage
public String getMessage()
Returns a detailed message of this exception. Overrides
Throwable.getMessage. It is customary in Java to use this method to
obtain exception information.
7.9. public abstract class GSSManager
This class contains methods to manage and query different GSS-API
providers. This saves the application from knowing the name of the
provider's factory class and instantiating it. When the application
has multiple providers installed on its system, it can use the
GSSManager to search through them and return one that supports a
desired underlying mechanism. It also provides a means for a single
point of control to set the preferred GSS-API provider. All
delegation done by the GSSContext, GSSCredential and GSSName classes
is then directed to implementing classes for that provider by
default.
Because this class locates and instantiates providers using the
standard Java provider architecture, applications are encouraged to
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make use of this class to maximize portability across implementations
rather than obtaining direct references to the factory classes from
the implementations.
The benefits of this approach are that applications can switch
between providers transparently and new providers can be added as
needed. Binary compatibility is maintained and applications can
switch providers even at runtime. The providers themselves can
change their implementation without having existing applications
break.
7.9.1. Example
// Import the Security class and the Provider class from
// the java security package
import java.security.Security;
import java.security.Provider;
// We want to use the GSS-API implementation from a provider that is
// registered with the system as FOOBAR.
Provider p = Security.getProvider("FOOBAR");
// What mechs does FOOBAR's GSS-API implementation support?
Oid[] supportedMechs = GSSManager.getMechs(p);
// Which provider is being used by default?
Provider p = GSSManager.getDefaultProvider();
print(p.getName()); // May not be "FOOBAR"
7.9.2. setDefaultProvider
public static void setDefaultProvider(Provider p)
throws java.security.NoSuchProviderException
Sets the desired provider for the GSSManager, and the wrapper classes
GSSName, GSSContext, and GSSCredential to use to delegate their calls
by default.
Parameters:
p The provider that should be used by default.
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7.9.3. getDefaultProvider
public static Provider getDefaultProvider()
Returns a Provider object that represents the provider that the
GSSManager, and the wrapper classes GSSName, GSSContext, and
GSSCredential and using to delegate their calls to.
7.9.4. getMechs
public static Oid[] getMechs(Provider p)
Returns an array of Oid objects, one for each mechanism available
within the GSS-API implementation supplied by the indicated provider.
A "null" value is returned when no mechanism are available (an
example of this would be when mechanism are dynamically configured,
and currently no mechanisms are installed).
Parameters:
p The provider that should be queried. "null" indicates
query the default GSS-API provider.
7.9.5. getNamesForMech
public static Oid[] getNamesForMech(Oid mech, Provider p)
throws GSSException
Returns name types Oids supported by the specified mechanism.
Parameters:
mech The Oid object for the mechanism to query.
p The provider that should be queried. "null" indicates
query the default GSS-API provider.
7.9.6. getMechsForName
public static Oid[] getMechsForName(Oid nameType, Provider p)
Returns an array of Oid objects, one for each mechanisms that support
the specific name type. "null" is returned when no mechanisms are
found to support the specified name type.
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Parameters:
nameType The Oid object for the name type to query.
p The provider that should be queried. "null" indicates
query the default GSS-API provider.
7.9.7. getProviderFromToken
public static Provider getProviderFromToken(byte[] firstToken)
Find a provider whose GSS-API implementation can support the
mechanism that is needed for accepting a context with the given
context establishment token. This call can be made only with the
first context establishment token received at the acceptor's end;
that token is required to follow the format defined in section 3.1 of
RFC 2078.
This call is useful to a context acceptor that has multiple GSS
implementations available to it and has to decide which one of them
to use such that the implementation supports the mechanism that the
context initiator wishes to use.
Parameters:
firstTokenThe first token that is emitted during a GSS-API
context establishment.
7.9.8. getProviderForMechanism
public static Provider[] getProvidersForMechanism(Oid mechOid)
A utility method to find the provider(s) whose GSS-API implementation
can support the given mechanism. The GSSManager class locates all
java security providers registered with the system and determines
from their respective GSSFactory implementations which ones support
this mechanism. It returns as array with all such provider objects.
An application can then choose a preferred provider from the returned
set.
Parameters:
mechOid The Oid of the desired mechanism.
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7.10. public class GSSName implements IGSSName
This concrete class is a wrapper around the interface IGSSName. An
application can use the GSSName class to perform all functionality of
the IGSSName interface eliminating the need to know the interface and
instantiating it from the provider. Its constructor performs the
following in one step: obtain the provider specific factory
(IGSSFactory) object, and obtain an IGSSName object from the factory
initialized with the parameters supplied in the constructor. The
wrapper delegates all its calls to this provider specific IGSSName
object.
It uses the preferred GSS-API provider to instantiate the IGSSName
implementation to delegate to. A default provider can optionally be
set by the application with the GSSManager.setDefaultProvider() call.
The GSSName class implements the IGSSName interface and thus provides
for all its functionality and also passes the compiler's type
checking when used in place of IGSSName. The methods from IGSSName
that GSSName implements are:
public boolean equals(IGSSName another) throws GSSException
public boolean equals(Object another)
public IGSSName canonicalize(Oid mechOid) throws GSSException
public byte[] export() throws GSSException
public String toString()
public Oid getStringNameType() throws GSSException
public boolean isAnonymous()
public boolean isMN()
Similarly, it inherits the following static constants:
public static final Oid NT_HOSTBASED_SERVICE
public static final Oid NT_USER_NAME
public static final Oid NT_MACHINE_UID_NAME
public static final Oid NT_STRING_UID_NAME
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public static final Oid NT_ANONYMOUS
public static final Oid NT_EXPORT_NAME
7.10.1. Example
Included below are code examples utilizing a GSSName object. The
code below creates a GSSName object, converts it to a mechanism name
(MN), performs a comparison, obtains a printable representation of
the name, exports it and then re-imports to obtain a new GSSName
object. This code uses the default GSS-API provider on the system.
// create an oid object for Kerberos v5 to export the name with
// Kerberos later on
Oid krb5 = new Oid("1.2.840.113554.1.2.2");
// create a host based service name
GSSName name = new GSSName("service@host",
GSSName.NT_HOSTBASED_SERVICE, null);
GSSName mechName = name.canonicalize(krb5);
// the above two steps are equivalent to the following constructor
GSSName mechName = new GSSName("service@host",
GSSName.NT_HOSTBASED_SERVICE, krb5, null);
// perform name comparison
if (name.equals(mechName))
print("Names are equals.");
// obtain textual representation of name and its printable
// name type
print(mechName.toString() +
mechName.getStringNameType().toString());
// export and re-import the name
byte [] exportName = mechName.export();
// create a new name object from the exported buffer
GSSName newName = new GSSName(exportName,
GSSName.NT_EXPORT_NAME, null);
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7.10.2. Constructors
public GSSName(String nameStr, Oid nameSpace, Provider p)
throws GSSException
Converts a contiguous string name from the specified namespace to a
GSSName object. In general, the GSSName object created will not be
an MN; the exception to this is if the namespace type parameter
indicates NT_EXPORT_NAME or if the GSS-API implementation is not
multi-mechanism.
Parameters:
nameStr The string representing a printable form of the name
to create.
nameType The Oid specifying the namespace of the printable name
supplied. "null" value can be used to specify that a
mechanism specific default printable syntax should be
assumed by each mechanism that examines nameStr.
p The preferred provider whose GSS-API implementation
should be used. "null" indicates use the default GSS-
API provider.
public GSSName(byte name[], Oid nameType, Provider p)
throws GSSException
Converts a contiguous byte array containing a name from the specified
namespace to a GSSName object. In general, the GSSName object
created will not be an MN; the exception to this is if the namespace
type parameter indicates NT_EXPORT_NAME or if the GSS-API
implementation is not multi-mechanism.
Parameters:
name The byte array containing the name to create.
nameType The Oid specifying the namespace of the name supplied
in the byte array. "null" value can be used to specify
that a mechanism specific default syntax should be
assumed by each mechanism that examines the byte
array.
p The preferred provider whose GSS-API implementation
should be used. "null" indicates use the default
GSS-API provider.
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public GSSName(String nameStr, Oid nameType, Oid mechType,
Provider p) throws GSSException
Converts a contiguous string name from the specified namespace to a
GSSName object that is a mechanism name (MN).
Parameters:
nameStr The string representing a printable form of the name
to create.
nameType The Oid specifying the namespace of the printable name
supplied. "null" value can be used to specify that a
mechanism specific default printable syntax should be
assumed when the mechanism examines nameStr.
mechType The Oid specifying the mechanism for which this name
should be created. "null" value can be used to
specify the default mechanism.
p The preferred provider whose GSS-API implementation
should be used. "null" indicates use the default GSS-
API provider. Implementations should then pick the
first registered provider on the system that supports
the mechanism mechType.
public GSSName(byte name[], Oid nameType, Oid mechType,
Provider p) throws GSSException
Converts a contiguous byte array containing a name from the specified
namespace to a GSSName object that is a mechanism name (MN).
Parameters:
name The byte array representing the name to create.
nameType The Oid specifying the namespace of the printable name
supplied. "null" value can be used to specify that a
mechanism specific default printable syntax should be
assumed when the mechanism examines nameStr.
mechType The Oid specifying the mechanism for which this name
should be created.
p The preferred provider whose GSS-API implementation
should be used. "null" indicates use the default GSS-
API provider. Implementations should then pick the
first registered provider on the system that supports
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the mechanism mechType.
7.10.3. getProvider
public java.security.Provider getProvider()
Returns the provider of the IGSSName implementation that this GSSName
object is delegating all its calls to. This is useful for
applications to track which GSS implementation this object came from.
It is important to not pass an IGSSName implementation (which
contains provider specific internal elements) to an IGSSCredential or
IGSSContext implementation from another provider.
7.11. public class GSSCredential implements IGSSCredential
This concrete class is a wrapper around the interface IGSSCredential
An application can use the GSSCredential class to perform all
functionality of the IGSSCredential interface eliminating the need to
know the interface and instantiating it from the provider. Its
constructor performs the following in one step: obtain the provider
specific factory (IGSSFactory) object, and obtain an IGSSCredential
object from the factory initialized with the parameters supplied in
the constructor. The wrapper delegates all its calls to this
provider specific IGSSName object.
It uses the preferred GSS-API provider to instantiate the
IGSSCredential implementation to delegate to. A default provider can
optionally be set by the application with the
GSSManager.setDefaultProvider() call.
The GSSCredential class implements the IGSSCredential interface and
thus provides for all its functionality and also passes the
compiler's type checking when used in place of IGSSCredential. The
methods from IGSSCredential that GSSCredential implements are:
public void dispose() throws GSSException
public IGSSName getName() throws GSSException
public IGSSName getName(Oid mechOID) throws GSSException
public int getRemainingLifetime() throws GSSException
public int getRemainingInitLifetime(Oid mech)
throws GSSException
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public int getRemainingAcceptLifetime(Oid mech)
throws GSSException
public int getUsage() throws GSSException
public int getUsage(Oid mechOID) throws GSSException
public Oid[] getMechs() throws GSSException
public void add(GSSName aName, int initLifetime,
int acceptLifetime, Oid mech,
int usage) throws GSSException
public boolean equals(Object another)
Similarly, it inherits the following static constants:
public static final int INITIATE_AND_ACCEPT
public static final int INITIATE_ONLY
public static final int ACCEPT_ONLY
public static final int INDEFINITE
7.11.1. Example
This example code demonstrates the creation of a GSSCredential object
for a specific entity, querying of its fields, and its release when
it is no longer needed. It uses the default GSS provider.
// start by creating a name object for the entity
GSSName name = new GSSName("userName", GSSName.NT_USER_NAME, null);
// now create a credential for the entity
GSSCredential cred = new GSSCredential(name,
GSSCredential.ACCEPT_ONLY, null);
// display credential information - name, remaining lifetime,
// and the mechanisms it has been acquired over
print(cred.getName().toString());
print(cred.getRemainingLifetime());
Oid [] mechs = cred.getMechs();
if (mechs != null) {
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for (int i = 0; i < mechs.length; i++)
print(mechs[i].toString());
}
// release system resources held by the credential
cred.dispose();
7.11.2. Constructors
public GSSCredential (int usage, Provider p) throws GSSException
Constructor for GSSCredential that acquires default credentials.
This will cause the GSS-API to use system specific defaults for the
set of mechanisms, name, and an INDEFINITE lifetime.
Parameters are:
usage The intended usage for this credential object. The
value of this parameter must be one of:
GSSCredential.ACCEPT_AND_INITIATE,
GSSCredential.ACCEPT_ONLY, GSSCredential.INITIATE_ONLY
p The preferred provider whose GSS-API implementation
should be used. "null" indicates use the default GSS-
API provider.
public GSSCredential (IGSSName aName, int lifetime,
Oid mechOid, int usage, Provider p)
throws GSSException
Constructor for GSSCredential that acquires a single mechanism
credential.
Parameters:
aName Name of the principal for whom this credential is to
be acquired. Use "null" to specify the default
principal.
lifetime The number of seconds that credentials should remain
valid. Use GSSCredential.INDEFINITE to request that
the credentials have the maximum permitted lifetime.
mechOid The oid of the desired mechanism. Use "(Oid) null" to
request the default mechanism(s).
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usage The intended usage for this credential object. The
value of this parameter must be one of:
GSSCredential.ACCEPT_AND_INITIATE,
GSSCredential.ACCEPT_ONLY, GSSCredential.INITIATE_ONLY
p The preferred provider whose GSS-API implementation
should be used. "null" indicates use the default GSS-
API provider.
public GSSCredential(IGSSName aName, int lifetime,
Oid mechs[], int usage, Provider p)
throws GSSException
Constructor for GSSCredential that acquires credentials over a set of
mechanisms. Acquires credentials for each of the mechanisms
specified in the array called mechs. To determine the list of
mechanisms' for which the acquisition of credentials succeeded, the
caller should use the GSSCredential.getMechs() method.
Parameters:
aName Name of the principal for whom this credential is to
be acquired. Use "null" to specify the default
principal.
lifetime The number of seconds that credentials should remain
valid. Use GSSCredential.INDEFINITE to request that
the credentials have the maximum permitted lifetime.
mechOid The array of mechanisms over which the credential is
to be acquired. Use "(Oid[]) null" for requesting a
system specific default set of mechanisms. Use an
empty array of Oid's such as "new Oid[] {}" to obtain
an empty credential which can later be built upon with
the GSSCredential.add() call.
usage The intended usage for this credential object. The
value of this parameter must be one of:
GSSCredential.ACCEPT_AND_INITIATE,
GSSCredential.ACCEPT_ONLY, GSSCredential.INITIATE_ONLY
p The preferred provider whose GSS-API implementation
should be used. "null" indicates use the default GSS-
API provider.
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7.11.3. getProvider
public java.security.Provider getProvider()
Returns the provider of the IGSSCredential implementation that this
GSSCredential object is delegating all its calls to. This is useful
for applications to track which GSS implementation this object came
from. It is important to not pass an IGSSCredential implementation
(which contains provider specific internal elements) to an
IGSSContext implementation from another provider.
7.12. public class GSSContext implements IGSSContext
This concrete class is a wrapper around the interface IGSSContext.
An application can use the GSSContext class to perform all
functionality of the IGSSContext interface eliminating the need to
know the interface and instantiating it from the provider. Its
constructor performs the following in one step: obtain the provider
specific factory (IGSSFactory) object, and obtain an IGSSContext
object from the factory initialized with the parameters supplied in
the constructor. The wrapper delegates all its calls to this
provider specific IGSSContext object.
It uses the preferred GSS-API provider to instantiate the IGSSContext
implementation to delegate to. The default provider can optionally
be set by the application with the GSSManager.setDefaultProvider()
call.
The GSSContext class implements the IGSSContext interface and thus
provides for all its functionality and also passes the compiler's
type checking when used in place of IGSSContext. The methods from
IGSSContext that GSSContext implements are:
public byte[] initSecContext(byte inputBuf[],
int offset, int len) throws GSSException
public int initSecContext(InputStream inStream,
OutputStream outStream) throws GSSException
public byte[] acceptSecContext(byte inTok[], int offset,
int len) throws GSSException
public void acceptSecContext(InputStream inStream,
OutputStream outStream) throws GSSException
public boolean isEstablished()
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public void dispose() throws GSSException
public int getWrapSizeLimit(int qop, boolean confReq,
int maxTokenSize) throws GSSException
public byte[] wrap(byte inBuf[], int offset, int len,
MessageProp msgProp) throws GSSException
public void wrap(InputStream inStream,
OutputStream outStream, MessageProp msgProp)
throws GSSException
public byte [] unwrap(byte[] inBuf, int offset, int len,
MessageProp msgProp) throws GSSException
public void unwrap(InputStream inStream,
OutputStream outStream, MessageProp msgProp)
throws GSSException
public byte[] getMIC(byte []inMsg, int offset, int len,
MessageProp msgProp) throws GSSException
public void getMIC(InputStream inStream,
OutputStream outStream, MessageProp msgProp)
throws GSSException
public void verifyMIC(byte []inTok, int tokOffset,
int tokLen, byte[] inMsg, int msgOffset,
int msgLen, MessageProp msgProp) throws GSSException
public void verifyMIC(InputStream tokStream,
InputStream msgStream, MessageProp msgProp)
throws GSSException
public byte [] export() throws GSSException
public void requestMutualAuth(boolean state)
throws GSSException
public void requestReplayDet(boolean state)
throws GSSException
public void requestSequenceDet(boolean state)
throws GSSException
public void requestCredDeleg(boolean state)
throws GSSException
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public void requestAnonymity(boolean state)
throws GSSException
public void requestConf(boolean state) throws GSSException
public void requestInteg(boolean state) throws GSSException
public void requestLifetime(int lifetime) throws GSSException
public void setChannelBinding(ChannelBinding cb)
throws GSSException
public boolean getCredDelegState()
public boolean getMutualAuthState()
public boolean getReplayDetState()
public boolean getSequenceDetState()
public boolean getAnonymityState()
public boolean isTransferable() throws GSSException
public boolean isProtReady()
public boolean getConfState()
public boolean getIntegState()
public int getLifetime()
public GSSName getSrcName() throws GSSException
public GSSName getTargName() throws GSSException
public Oid getMech() throws GSSException
public GSSCredential getDelegCred() throws GSSException
public boolean isInitiator() throws GSSException
Similarly, it inherits the following static constant:
public static final int INDEFINITE
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7.12.1. Example
The example code presented below demonstrates the usage of the
GSSContext object for the initiating peer. Different operations on
the GSSContext object are presented, including: object instantiation,
setting of desired flags, context establishment, query of actual
context flags, per-message operations on application data, and
finally context deletion.
// start by creating the name for a service entity
GSSName targetName = new GSSName("service@host",
GSSName.NT_HOSTBASED_SERVICE, null);
// create a context using default credentials for the above entity
// and the implementation specific default mechanism
GSSContext context = new GSSContext(targetName,
null, /* default mechanism */
null, /* default credentials */
GSSContext.INDEFINITE,
null /* default provider */);
// set desired context options - all others are false by default
context.requestConf(true);
context.requestMutualAuth(true);
context.requestReplayDet(true);
context.requestSequenceDet(true);
// establish a context between peers - using byte arrays
byte []inTok = new byte[0];
try {
do {
byte[] outTok = context.init(inTok, 0, inTok.length);
// send the token if present
if (outTok != null)
sendToken(outTok);
// check if we should expect more tokens
if (context.isEstablished())
break;
// another token expected from peer
inTok = readToken();
} while (true);
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} catch (GSSException e) {
print("GSSAPI error: " + e.getMessage());
}
// display context information
print("Remaining lifetime in seconds = " + context.getLifetime());
print("Context mechanism = " + context.getMech().toString());
print("Initiator = " + context.getSrcName().toString());
print("Acceptor = " + context.getTargName().toString());
if (context.getConfState())
print("Confidentiality security service available");
if (context.getIntegState())
print("Integrity security service available");
// perform wrap on an application supplied message, appMsg,
// using QOP = 0, and requesting privacy service
byte [] appMsg ...
MessageProp mProp = new MessageProp(0, true);
byte []tok = context.wrap(appMsg, 0, appMsg.length, mProp);
if (mProp.getPrivacy())
print("Message protected with privacy.");
sendToken(tok);
// release the local-end of the context
context.dispose();
7.12.2. Constructors
The GSSContext class provides the following constructors. In
addition to these, this class also provides an overloaded form of
each of these constructors that takes a java.security.Provider object
as the last parameter. The overloaded constructor with the Provider
argument is indentical to the one without the Provider with the
exception that the GSSContext class uses the specified Provider to
instantiate the IGSSContext implementation. The constructors with
the Provider argument are useful when the application wishes to
instantiate from a given provider without setting the default
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provider globally in the GSSManager class. The sample code shown in
8.2 demonstrates the use such a constructor.
public GSSContext(GSSName peer, Oid mechOid,
GSSCredential myCred, int lifetime, Provider p)
throws GSSException
Constructor for creating a context on the initiator's side. Context
flags may be modified through the mutator methods prior to calling
GSSContext.initSecContext().
Parameters:
peer Name of the target peer.
mechOid Oid of the desired mechanism. Use "null" to request
default mechanism.
myCred Credentials of the initiator. Use "null" to act as a
default initiator principal.
lifetime The request lifetime, in seconds, for the credential.
p The preferred provider whose GSS-API implementation
should be used. "null" indicates use the default GSS-
API provider.
public GSSContext(GSSCredential myCred, Provider p) throws
GSSException
Constructor for creating a context on the acceptor' side. The
context's properties will be determined from the input token supplied
to the accept method.
Parameters:
myCred Credentials for the acceptor. Use "null" to act as a
default acceptor principal.
p The preferred provider whose GSS-API implementation
should be used. "null" indicates use the default GSS-
API provider.
public GSSContext(byte [] interProcessToken, Provider p) throws
GSSException
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Constructor for creating a previously exported context. The context
properties will be determined from the input token and can't be
modified through the set methods.
Parameters:
interProcessToken
The token previously emitted from the export method.
p The preferred provider whose GSS-API implementation
should be used. "null" indicates use the default GSS-
API provider.
7.12.3. getProvider
public java.security.Provider getProvider()
Returns the provider of the IGSSContext implementation that this
GSSContext object is delegating all its calls to. This is useful for
applications to track which GSS implementation this object came from.
It is important to not pass an IGSSName or an IGSSCredential
implementation (which contain provider specific internal elements) to
an IGSSContext implementation from another provider.
8. Sample Applications
Full Copyright Statement
Copyright (C) The Internet Society (1999). All Rights Reserved.
This document and translations of it may be copied and furnished
to others, and derivative works that comment on or otherwise explain
it or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not
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be revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on
an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
8.1. Simple GSS Context Initiator
import org.ietf.JGSS.*;
/**
* This is the sketch for a simple client program that acts as a GSS
* context initiator. This sample program shows how to use the
* Java bindings of the GSS-API specified in
* draft-ietf-cat-gssv2-javabind-02.txt.
*
* This application assumes the existence of a GSS-API
* implementation that supports the mechanism that it will need and
* is present as a library package (org.ietf.JGSS) either as part of
* the standard JRE or in the CLASSPATH the application specifies.
*/
public class SimpleClient {
private String serviceName; // name of peer (ie. server)
private GSSCredential clientCred = null;
private GSSContext context = null;
private Oid mech; // underlying mechanism to use
...
...
/**
* The SimpleClient method that connects to the server,
* establishes a security context with it, sends some data
* across and gets back a response.
*/
private void clientActions() {
initializeGSS();
establishContext();
doCommunication();
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}
/**
* Acquire credentials for the client.
*/
private void initializeGSS() {
// Uncommenting the following line will cause the
// GSS-framework to use the specified provider
// when using a default provider.
// The GSS API framework in org.ietf.JGSS will then
// instantiate names, credentials, and the context from that
// provider:
// GSSManager.setDefaultProvider("FOOBAR");
try {
clientCred = new GSSCredential(null /*default princ.*/,
GSSCredential.INDEFINITE /* max lifetime */,
mech /* mechanism to use */,
GSSCredential.INITIATE_ONLY /* init context */,
null /* default provider */);
print("GSSCredential created for " +
cred.getName().toString());
print("Credential lifetime (sec)=" +
cred.getRemainingLifetime());
} catch (GSSException e) {
print("GSS-API error in credential acquisition: "
+ e.getMessage());
...
...
}
...
...
}
/**
* Does the security context establishment with the
* server.
*/
private void establishContext() {
byte[] inToken = new byte[0];
byte[] outToken = null;
try {
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GSSName peer = new GSSName(serviceName,
GSSName.NT_HOSTBASED_SERVICE, null);
context = new GSSContext(peer, mech, gssCred,
GSSContext.INDEFINITE/*lifetime*/,
null);
// Will need to support confidentiality
context.requestConf(true);
while (!context.isEstablished()) {
outToken = context.initSecContext(inToken, 0,
inToken.length);
if (outToken != null)
writeGSSToken(outToken);
if (!context.isEstablished())
inToken = readGSSToken();
}
GSSName peer = context.getSrcName();
print("Security context established with " + peer +
" using underlying mechanism " + mech.toString());
} catch (GSSException e) {
print("GSS-API error during context establishment: "
+ e.getMessage());
...
...
}
...
...
}
/**
* Sends some data to the server and reads back the
* response.
*/
private void doCommunication() {
byte[] inToken = null;
byte[] outToken = null;
byte[] buffer;
// Container for multiple input-output arguments to and
// from the per-message routines (e.g., wrap/unwrap).
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MessageProp messgInfo = new MessageProp();
try {
/*
* Now send some bytes to the server to be
* processed. They will be integrity protected but
* not encrypted for privacy.
*/
buffer = readFromFile();
// Set privacy to false and use the default QOP
messgInfo.setPrivacy(false);
outToken = context.wrap(buffer, 0, buffer.length,
messgInfo);
writeGSSToken(outToken);
/*
* Now read the response from the server.
*/
inToken = readGSSToken();
buffer = context.unwrap(inToken, 0, inToken.length,
messgInfo);
// All ok if no exception was thrown!
GSSName peer = context.getSrcName();
print("Message from " + peer.toString()
+ " arrived.");
print("Was it encrypted? " +
messgInfo.getPrivacy());
print("Duplicate Token? " +
messgInfo.isDuplicateToken());
print("Old Token? " +
messgInfo.isOldToken());
print("Unsequenced Token? " +
messgInfo.isUnseqToken());
print("Gap Token? " +
messgInfo.isGapToken());
...
...
} catch (GSSException e) {
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print("GSS-API error in per-message calls: "
+ e.getMessage());
...
...
}
...
...
} // end of doCommunication method
...
...
} // end of class SimpleClient
8.2. GSS Context Acceptor Using Multiple Providers
import org.ietf.JGSS.*;
import java.security.Provider;
/**
* This is the sketch for a simple server program that acts as a GSS
* context acceptor. This sample program shows how to use the Java
* bindings of the GSS-API specified in
* draft-ietf-cat-gssv2-javabind-02.txt.
*
* This application assumes the existence of one or more GSS-API
* implementations that are registered via different providers with
* the standard java.security.Security class. It depends on
* functionality in the GSSManager to pick the right implementation
* that suites its needs.
*/
public class SimpleServer {
private String serviceName;
...
...
/**
* This method performs the infinite loop where the
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* SimpleServer accepts connections from different clients,
* establishes security contexts with them and provides them
* with some service.
*/
private void loop() {
...
...
// Loop infinitely
while (true) {
Socket s = serverSock.accept();
// Start a new thread to serve this connection
Thread serverThread = new ServerThread(s);
serverThread.start();
}
}
/**
* Inner class ServerThread whose run() method provides the
* secure service to a connection. run() gets called by the JVM
* automatically when Thread.start() is invoked in serverLoop().
*/
private class ServerThread extends Thread {
...
...
/**
* Deals with the connection from one client. It also
* handles all GSSException's thrown while talking to
* this client.
*/
public void run() {
byte[] inToken = null;
byte[] outToken = null;
byte[] buffer;
GSSNameInt peer;
// Container for multiple input-output arguments to and
// from the per-message routines (ie. wrap/unwrap).
MessageProp supplInfo = new MessageProp();
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GSSContextInt secContext = null;
try {
// Obtain the first context establishment GSS token
inToken = readGSSToken();
// Tell the GSSManager to find a GSS
// implementation that supports this mechanism. The
// token is parsed by the GSSManager to determine
// the mechanism Oid using the format defined in
// RFC 2078 Section 3.1.
Provider p =
GSSManager.getProviderFromToken(inToken);
// Create a GSSName and a GSSCredential using the
// same provider. It is important to not pass a
// GSSName and GSSCredential (which contain provider
// specific internal elements) to a GSSContext from
// another provider.
GSSName name = new GSSName(serviceName,
GSSName.NT_HOSTBASED_SERVICE, p);
GSSCredential cred = new GSSCredential(name,
GSSCredential.INDEFINITE,
null,
GSSCredential.ACCEPT_ONLY,
p);
// Now do the context establishment loop
GSSContext context = new GSSContext(cred, null);
while (!context.isEstablished()) {
outToken = context.acceptSecContext(inToken, 0,
inToken.length);
if (outToken != null)
writeGSSToken(outToken);
if (!context.isEstablished())
inToken = readGSSToken();
}
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// SimpleServer wants confidentiality to be
// available. Check for it.
if (!context.getConfState()){
...
...
}
GSSNameInt peer = context.getSrcName();
Oid mech = context.getMech();
print("Security context established with " +
peer.toString() +
" using underlying mechanism " +
mech.toString() +
" from Provider " +
context.getProvider().getName());
// Now read the bytes sent by the client to be
// processed.
inToken = readGSSToken();
// Unwrap the message
buffer = context.unwrap(inToken, 0, inToken.length,
supplInfo);
// All ok if no exception was thrown!
// Print other supplementary per-message status
// information
print("Message from " +
peer.toString() + " arrived.");
print("Was it encrypted? " +
supplInfo.getPrivacy());
print("Duplicate Token? " +
supplInfo.isDuplicateToken());
print("Old Token? " + supplInfo.isOldToken());
print("Unsequenced Token? " +
supplInfo.isUnseqToken());
print("Gap Token? " + supplInfo.isGapToken());
/*
* Now process the bytes and send back an encrypted
* response.
*/
buffer = serverProcess(buffer);
// Encipher it and send it across
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supplInfo.setPrivacy(true); // privacy requested
supplInfo.setQOP(0); // default QOP
outToken = context.wrap(buffer, 0, buffer.length,
supplInfo);
writeGSSToken(outToken);
} catch (GSSException e) {
print("GSS-API Error: " + e.getMessage());
// Alternatively, could call e.getMajorMessage()
// and e.getMinorMessage()
print("Abandoning security context.");
...
...
}
...
...
} // end of run method in ServerThread
} // end of inner class ServerThread
...
...
} // end of class SimpleServer
8.3. GSS Context Initiator Using the Provider Factory Directly
import org.ietf.JGSS.*;
/**
* This is the sketch for a another client program that acts as a
* GSS context initiator. This sample program shows how to use the
* Java bindings of the GSS-API specified in
* draft-ietf-cat-gssv2-javabind-02.txt.
*
* This application is very aware of the provider classes that it
* will use. It may be that this application ships along with a GSS
* implementation that is specific to its needs and the application
* chooses to directly instantiate the desired factory. This API is
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* not encouraged for applications that wish to be portable.
*/
public class AnotherClient {
private GSSFactory factory = null;
private String serviceName; // name of peer (ie. server)
private IGSSCredential clientCred = null;
private IGSSContext context = null;
private Oid mech; // underlying mechanism to use
...
...
/**
* The AnotherClient method that connects to the server,
* establishes a security context with it, sends some data
* across and gets back a response.
*/
private void clientActions() {
// Get the factory directly from the desired implementation
factory = new com.xyz.GSSAPI.MyFactory();
initializeGSS();
establishContext();
doCommunication();
}
/**
* Acquire credentials for the client.
*/
private void initializeGSS() {
try {
clientCred = factory.createCredentials(
null /* default principal*/,
IGSSCredential.INDEFINITE /* max lifetime */,
mech /* mechanism to use */,
IGSSCredential.INITIATE_ONLY /* init context */);
print("Credential created for " +
cred.getName().toString());
print("Credential lifetime (sec)=" +
cred.getRemainingLifetime());
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} catch (GSSException e) {
print("GSS-API error in credential acquisition: "
+ e.getMessage());
...
...
}
}
/**
* Does the security context establishment with the
* server.
*/
private void establishContext() {
byte[] inToken = new byte[0];
byte[] outToken = null;
try {
GSSName peer = factory.createName(serviceName,
IGSSName.NT_HOSTBASED_SERVICE);
context = factory.createContext(peer, mech, gssCred,
IGSSContext.INDEFINITE/*lifetime*/);
// Will need to support confidentiality
context.requestConf(true);
while (!context.isEstablished()) {
outToken = context.initSecContext(inToken, 0,
inToken.length);
if (outToken != null)
writeGSSToken(outToken);
if (!context.isEstablished())
inToken = readGSSToken();
}
GSSName peer = context.getSrcName();
print("Security context established with " + peer +
" using underlying mechanism " + mech.toString());
} catch (GSSException e) {
print("GSS-API error during context establishment: "
+ e.getMessage());
...
...
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}
...
...
}
/**
* Sends some data to the server and reads back the response.
*/
private void doCommunication() {
byte[] inToken = null;
byte[] outToken = null;
byte[] buffer;
// Container for multiple input-output arguments to and
// from the per-message routines (ie. wrap/unwrap).
MessageProp messgInfo = new MessageProp();
try {
/*
* Now send some bytes to the server to be
* processed. They will be integrity protected but
* not encrypted for privacy.
*/
buffer = readFromFile();
// Set privacy to false and use the default QOP
messgInfo.setPrivacy(false);
outToken = context.wrap(buffer, 0, buffer.length,
messgInfo);
writeGSSToken(outToken);
/*
* Now read the response from the server.
*/
inToken = readGSSToken();
buffer = context.unwrap(inToken, 0, inToken.length,
messgInfo);
// All ok if no exception was thrown!
GSSName peer = context.getSrcName();
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print("Message from " +
peer.toString() + " arrived.");
print("Was it encrypted? " +
messgInfo.getPrivacy());
print("Duplicate Token? " +
messgInfo.isDuplicateToken());
print("Old Token? " +
messgInfo.isOldToken());
print("Unsequenced Token? " +
messgInfo.isUnseqToken());
print("Gap Token? " +
messgInfo.isGapToken());
...
...
} catch (GSSException e) {
print("GSS-API error in per-message calls: "
+ e.getMessage());
...
...
}
...
...
} // end of doCommunication method
...
...
} // end of class AnotherClient
9. Acknowledgments
This proposed API leverages earlier work performed by the IETF's CAT
WG as outlined in both RFC 2078 and J. Wray's C-bindings draft for
the GSS-API. Many conceptual definitions, implementation directions,
and explanations have been included from the C-bindings draft.
We would like to thank Mike Eisler, Lin Ling, Ram Marti, Michael
Saltz and other members of Sun's development team for their helpful
input, comments and suggestions.
We would also like to thank Joe Salowey, and Michael Smith for many
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insightful ideas and suggestions that have contributed to this draft.
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10. Bibliography
[GSSAPIv2]
J. Linn, "Generic Security Service Application Program Interface,
Version 2", RFC 2078, January 1997.
[GSSAPIv2-UPDATE]
J. Linn, "Generic Security Service Application Program Interface,
Version 2, Update 1", IETF work in progress, Internet Draft, July
1998.
[GSSAPI-Cbind]
J. Wray, "Generic Security Service API Version 2 : C-bindings", IETF
work in progress, Internet Draft, July 1998.
[KERBEROS_V5]
J. Linn, "The Kerberos Version 5 GSS-API Mechanism", RFC 1964, June
1996.
[SPKM]
C. Adams, "The Simple Public-Key GSS-API Mechanism", RFC 2025,
October 1996.
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11. Author's Address
Address comments related to this memorandum to:
<cat-ietf@mit.edu>
Jack Kabat
ValiCert, Inc.
1215 Terra Bella Avenue
Mountain View, CA
94043, USA
Phone: +1-650-567-5496
E-mail: jackk@valicert.com
Mayank Upadhyay
Sun Microsystems, Inc.
901 San Antonio Road, MS CUP02-102
Palo Alto, CA 94303
Phone: +1-408-517-5956
E-mail: mdu@eng.sun.com
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