public abstract class GSSManager extends Object
GSSName, GSSCredential, and GSSContext. It also has methods to query for the list
of available mechanisms and the nametypes that each mechanism
supports.
An instance of the default GSSManager subclass
may be obtained through the static method getInstance, but applications are free to instantiate other subclasses
of GSSManager. The default GSSManager instance
will support the Kerberos v5 GSS-API mechanism in addition to any
others. This mechanism is identified by the Oid "1.2.840.113554.1.2.2"
and is defined in RFC 1964.
A subclass extending the GSSManager abstract class may be
implemented as a modular provider based layer that utilizes some well
known service provider specification. The GSSManager API
allows the application to set provider preferences on
such an implementation. These methods also allow the implementation to
throw a well-defined exception in case provider based configuration is
not supported. Applications that expect to be portable should be aware
of this and recover cleanly by catching the exception.
It is envisioned that there will be three most common ways in which providers will be used:
The GSSManager class has two methods that enable these modes of
usage: addProviderAtFront and
addProviderAtEnd. These methods
have the effect of creating an ordered list of <provider,
oid> pairs where each pair indicates a preference of provider
for a given oid.
It is important to note that there are certain interactions
between the different GSS-API objects that are created by a
GSSManager, where the provider that is used for a particular mechanism
might need to be consistent across all objects. For instance, if a
GSSCredential contains elements from a provider p for a mechanism
m, it should generally be passed in to a GSSContext that will use
provider p for the mechanism m. A simple rule of thumb
that will maximize portability is that objects created from different
GSSManager's should not be mixed, and if possible, a different
GSSManager instance should be created if the application wants to invoke
the addProviderAtFront method on a GSSManager that has
already created an object.
Here is some sample code showing how the GSSManager might be used:
GSSManager manager = GSSManager.getInstance();
Oid krb5Mechanism = new Oid("1.2.840.113554.1.2.2");
Oid krb5PrincipalNameType = new Oid("1.2.840.113554.1.2.2.1");
// Identify who the client wishes to be
GSSName userName = manager.createName("duke", GSSName.NT_USER_NAME);
// Identify the name of the server. This uses a Kerberos specific
// name format.
GSSName serverName = manager.createName("nfs/foo.sun.com",
krb5PrincipalNameType);
// Acquire credentials for the user
GSSCredential userCreds = manager.createCredential(userName,
GSSCredential.DEFAULT_LIFETIME,
krb5Mechanism,
GSSCredential.INITIATE_ONLY);
// Instantiate and initialize a security context that will be
// established with the server
GSSContext context = manager.createContext(serverName,
krb5Mechanism,
userCreds,
GSSContext.DEFAULT_LIFETIME);
The server side might use the following variation of this source:
// Acquire credentials for the server
GSSCredential serverCreds = manager.createCredential(serverName,
GSSCredential.DEFAULT_LIFETIME,
krb5Mechanism,
GSSCredential.ACCEPT_ONLY);
// Instantiate and initialize a security context that will
// wait for an establishment request token from the client
GSSContext context = manager.createContext(serverCreds);
GSSName,
GSSCredential,
GSSContext| Constructor and Description |
|---|
GSSManager() |
| Modifier and Type | Method and Description |
|---|---|
abstract void |
addProviderAtEnd(Provider p,
Oid mech)
This method is used to indicate to the GSSManager that the
application would like a particular provider to be used if no other
provider can be found that supports the given mechanism.
|
abstract void |
addProviderAtFront(Provider p,
Oid mech)
This method is used to indicate to the GSSManager that the
application would like a particular provider to be used ahead of all
others when support is desired for the given mechanism.
|
abstract GSSContext |
createContext(byte[] interProcessToken)
Factory method for creating a previously exported context.
|
abstract GSSContext |
createContext(GSSCredential myCred)
Factory method for creating a context on the acceptor' side.
|
abstract GSSContext |
createContext(GSSName peer,
Oid mech,
GSSCredential myCred,
int lifetime)
Factory method for creating a context on the initiator's
side.
|
abstract GSSCredential |
createCredential(GSSName name,
int lifetime,
Oid[] mechs,
int usage)
Factory method for acquiring credentials over a set of
mechanisms.
|
abstract GSSCredential |
createCredential(GSSName name,
int lifetime,
Oid mech,
int usage)
Factory method for acquiring a single mechanism credential.
|
abstract GSSCredential |
createCredential(int usage)
Factory method for acquiring default credentials.
|
abstract GSSName |
createName(byte[] name,
Oid nameType)
Factory method to convert a byte array containing a
name from the specified namespace to a GSSName object.
|
abstract GSSName |
createName(byte[] name,
Oid nameType,
Oid mech)
Factory method to convert a byte array containing a
name from the specified namespace to a GSSName object and canonicalize
it at the same time for a mechanism.
|
abstract GSSName |
createName(String nameStr,
Oid nameType)
Factory method to convert a string name from the
specified namespace to a GSSName object.
|
abstract GSSName |
createName(String nameStr,
Oid nameType,
Oid mech)
Factory method to convert a string name from the
specified namespace to a GSSName object and canonicalize it at the
same time for a mechanism.
|
static GSSManager |
getInstance()
Returns the default GSSManager implementation.
|
abstract Oid[] |
getMechs()
Returns a list of mechanisms that are available to GSS-API callers
through this GSSManager.
|
abstract Oid[] |
getMechsForName(Oid nameType)
Returns a list of mechanisms that support the indicated name type.
|
abstract Oid[] |
getNamesForMech(Oid mech)
Returns then name types supported by the indicated mechanism.
|
public static GSSManager getInstance()
public abstract Oid[] getMechs()
getInstance() method includes the Oid
"1.2.840.113554.1.2.2" in its list. This Oid identifies the Kerberos
v5 GSS-API mechanism that is defined in RFC 1964.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).public abstract Oid[] getNamesForMech(Oid mech) throws GSSException
The default GSSManager instance includes support for the Kerberos v5
mechanism. When this mechanism ("1.2.840.113554.1.2.2") is indicated,
the returned list will contain at least the following nametypes:
GSSName.NT_HOSTBASED_SERVICE,
GSSName.NT_EXPORT_NAME, and the
Kerberos v5 specific Oid "1.2.840.113554.1.2.2.1". The namespace for
the Oid "1.2.840.113554.1.2.2.1" is defined in RFC 1964.
mech - the Oid of the mechanism to queryGSSException - containing the following
major error codes:
GSSException.BAD_MECH
GSSException.FAILUREgetMechsForName(Oid)public abstract Oid[] getMechsForName(Oid nameType)
The Kerberos v5 mechanism ("1.2.840.113554.1.2.2") will always be
returned in this list when the indicated nametype is one of
GSSName.NT_HOSTBASED_SERVICE,
GSSName.NT_EXPORT_NAME, or
"1.2.840.113554.1.2.2.1".
nameType - the Oid of the name type to look fornull is returned when no
mechanisms are found to support the specified name type.getNamesForMech(Oid)public abstract GSSName createName(String nameStr, Oid nameType) throws GSSException
GSSName object created will contain multiple
representations of the name, one for each mechanism that is
supported; 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. It is
not recommended to use this method with a NT_EXPORT_NAME type because
representing a previously exported name consisting of abitrary bytes
as a String might cause problems with character encoding schemes. In
such cases it is recommended that the bytes be passed in directly to
the overloaded form of this method createName.nameStr - the string representing a printable form of the name to
create.nameType - the Oid specifying the namespace of the printable name
supplied. null can be used to specify
that a mechanism specific default printable syntax should
be assumed by each mechanism that examines nameStr.
It is not advisable to use the nametype NT_EXPORT_NAME with this
method.GSSException - containing the following
major error codes:
GSSException.BAD_NAMETYPE,
GSSException.BAD_NAME,
GSSException.BAD_MECH,
GSSException.FAILUREGSSName,
GSSName.NT_EXPORT_NAMEpublic abstract GSSName createName(byte[] name, Oid nameType) throws GSSException
GSSName object created will contain multiple
representations of the name, one for each mechanism that is
supported; 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. The bytes that are
passed in are interpreted by each underlying mechanism according to
some encoding scheme of its choice for the given nametype.name - the byte array containing the name to createnameType - the Oid specifying the namespace of the name supplied
in the byte array. null can be used to specify that a
mechanism specific default syntax should be assumed by each mechanism
that examines the byte array.GSSException - containing the following
major error codes:
GSSException.BAD_NAMETYPE,
GSSException.BAD_NAME,
GSSException.BAD_MECH,
GSSException.FAILUREGSSName,
GSSName.NT_EXPORT_NAMEpublic abstract GSSName createName(String nameStr, Oid nameType, Oid mech) throws GSSException
createName and then also the GSSName.canonicalize.nameStr - the string representing a printable form of the name to
create.nameType - the Oid specifying the namespace of the printable name
supplied. null can be used to specify
that a mechanism specific default printable syntax should
be assumed by each mechanism that examines nameStr.
It is not advisable to use the nametype NT_EXPORT_NAME with this
method.mech - Oid specifying the mechanism for which the name should be
canonicalizedGSSException - containing the following
major error codes:
GSSException.BAD_NAMETYPE,
GSSException.BAD_NAME,
GSSException.BAD_MECH,
GSSException.FAILUREGSSName.canonicalize(Oid),
GSSName.NT_EXPORT_NAMEpublic abstract GSSName createName(byte[] name, Oid nameType, Oid mech) throws GSSException
createName and then also GSSName.canonicalize.name - the byte array containing the name to createnameType - the Oid specifying the namespace of the name supplied
in the byte array. null can be used to specify that a
mechanism specific default syntax should be assumed by each mechanism
that examines the byte array.mech - Oid specifying the mechanism for which the name should be
canonicalizedGSSException - containing the following
major error codes:
GSSException.BAD_NAMETYPE,
GSSException.BAD_NAME,
GSSException.BAD_MECH,
GSSException.FAILUREGSSName.canonicalize(Oid),
GSSName.NT_EXPORT_NAMEpublic abstract GSSCredential createCredential(int usage) throws GSSException
GSS-API mechanism providers must impose a local access-control
policy on callers to prevent unauthorized callers from acquiring
credentials to which they are not entitled. The kinds of permissions
needed by different mechanism providers will be documented on a
per-mechanism basis. A failed permission check might cause a SecurityException to be thrown from
this method.
usage - The intended usage for this credential object. The value
of this parameter must be one of:
GSSCredential.INITIATE_AND_ACCEPT,
GSSCredential.ACCEPT_ONLY, and
GSSCredential.INITIATE_ONLY.GSSException - containing the following
major error codes:
GSSException.BAD_MECH,
GSSException.BAD_NAMETYPE,
GSSException.BAD_NAME,
GSSException.CREDENTIALS_EXPIRED,
GSSException.NO_CRED,
GSSException.FAILUREGSSCredentialpublic abstract GSSCredential createCredential(GSSName name, int lifetime, Oid mech, int usage) throws GSSException
GSS-API mechanism providers must impose a local access-control
policy on callers to prevent unauthorized callers from acquiring
credentials to which they are not entitled. The kinds of permissions
needed by different mechanism providers will be documented on a
per-mechanism basis. A failed permission check might cause a SecurityException to be thrown from
this method.
Non-default values for lifetime cannot always be honored by the
underlying mechanisms, thus applications should be prepared to call
getRemainingLifetime
on the returned credential.
name - the 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_LIFETIME to request that the credentials
have the maximum permitted lifetime. Use GSSCredential.DEFAULT_LIFETIME to
request default credential lifetime.mech - the Oid of the desired mechanism. Use (Oid) null
to request the default mechanism.usage - The intended usage for this credential object. The value
of this parameter must be one of:
GSSCredential.INITIATE_AND_ACCEPT,
GSSCredential.ACCEPT_ONLY, and
GSSCredential.INITIATE_ONLY.GSSException - containing the following
major error codes:
GSSException.BAD_MECH,
GSSException.BAD_NAMETYPE,
GSSException.BAD_NAME,
GSSException.CREDENTIALS_EXPIRED,
GSSException.NO_CRED,
GSSException.FAILUREGSSCredentialpublic abstract GSSCredential createCredential(GSSName name, int lifetime, Oid[] mechs, int usage) throws GSSException
GSSCredential.getMechs method.
GSS-API mechanism providers must impose a local access-control
policy on callers to prevent unauthorized callers from acquiring
credentials to which they are not entitled. The kinds of permissions
needed by different mechanism providers will be documented on a
per-mechanism basis. A failed permission check might cause a SecurityException to be thrown from
this method.
Non-default values for lifetime cannot always be honored by the
underlying mechanisms, thus applications should be prepared to call
getRemainingLifetime
on the returned credential.
name - the 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_LIFETIME to request that the credentials
have the maximum permitted lifetime. Use GSSCredential.DEFAULT_LIFETIME to
request default credential lifetime.mechs - an array of Oid's indicating the 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:
GSSCredential.INITIATE_AND_ACCEPT,
GSSCredential.ACCEPT_ONLY, and
GSSCredential.INITIATE_ONLY.GSSException - containing the following
major error codes:
GSSException.BAD_MECH,
GSSException.BAD_NAMETYPE,
GSSException.BAD_NAME,
GSSException.CREDENTIALS_EXPIRED,
GSSException.NO_CRED,
GSSException.FAILUREGSSCredentialpublic abstract GSSContext createContext(GSSName peer, Oid mech, GSSCredential myCred, int lifetime) throws GSSException
SecurityException
to be thrown from this method.
Non-default values for lifetime cannot always be honored by the
underlying mechanism, thus applications should be prepared to call
getLifetime on the returned
context.
peer - the name of the target peer.mech - the Oid of the desired mechanism. Use null
to request the default mechanism.myCred - the credentials of the initiator. Use
null to act as the default initiator principal.lifetime - the lifetime, in seconds, requested for the
context. Use GSSContext.INDEFINITE_LIFETIME to request that the context have the
maximum permitted lifetime. Use GSSContext.DEFAULT_LIFETIME to request a default lifetime for the
context.GSSException - containing the following
major error codes:
GSSException.NO_CRED
GSSException.CREDENTIALS_EXPIRED
GSSException.BAD_NAMETYPE
GSSException.BAD_MECH
GSSException.FAILUREGSSContextpublic abstract GSSContext createContext(GSSCredential myCred) throws GSSException
SecurityException
to be thrown from this method.myCred - the credentials for the acceptor. Use
null to act as a default acceptor principal.GSSException - containing the following
major error codes:
GSSException.NO_CRED
GSSException.CREDENTIALS_EXPIRED
GSSException.BAD_MECH
GSSException.FAILUREGSSContextpublic abstract GSSContext createContext(byte[] interProcessToken) throws GSSException
Implementations are not required to support the inter-process
transfer of security contexts. Before exporting a context, calling
the GSSContext.isTransferable
will indicate if the context is transferable. Calling this method in
an implementation that does not support it will result in a
GSSException with the error
code GSSException.UNAVAILABLE.
Some mechanism providers might require that the caller be granted
permission to initiate or accept a security context. A failed
permission check might cause a SecurityException to be thrown from this method.
interProcessToken - the token previously emitted from the
export method.GSSException - containing the following
major error codes:
GSSException.NO_CONTEXT,
GSSException.DEFECTIVE_TOKEN,
GSSException.UNAVAILABLE,
GSSException.UNAUTHORIZED,
GSSException.FAILUREGSSContextpublic abstract void addProviderAtFront(Provider p, Oid mech) throws GSSException
Oid for the mechanism,
the GSSManager must use the indicated provider ahead of all others
no matter what the mechanism is. Only when the indicated provider
does not support the needed mechanism should the GSSManager move on
to a different provider.
Calling this method repeatedly preserves the older settings but
lowers them in preference thus forming an ordered list of provider
and Oid pairs that grows at the top.
Calling addProviderAtFront with a null Oid will remove
all previous preferences that were set for this provider in the
GSSManager instance. Calling addProviderAtFront with a non-null
Oid will remove any previous preference that was set
using this mechanism and this provider together.
If the GSSManager implementation does not support an SPI with a pluggable provider architecture it should throw a GSSException with the status code GSSException.UNAVAILABLE to indicate that the operation is unavailable.
Suppose an application desired that the provider A always be checked first when any mechanism is needed, it would call:
GSSManager mgr = GSSManager.getInstance();
// mgr may at this point have its own pre-configured list
// of provider preferences. The following will prepend to
// any such list:
mgr.addProviderAtFront(A, null);
Now if it also desired that the mechanism of Oid m1 always be
obtained from the provider B before the previously set A was checked,
it would call:
mgr.addProviderAtFront(B, m1);
The GSSManager would then first check with B if m1 was needed. In
case B did not provide support for m1, the GSSManager would continue
on to check with A. If any mechanism m2 is needed where m2 is
different from m1 then the GSSManager would skip B and check with A
directly.Suppose at a later time the following call is made to the same GSSManager instance:
mgr.addProviderAtFront(B, null)
then the previous setting with the pair (B, m1) is subsumed by this
and should be removed. Effectively the list of preferences now
becomes {(B, null), (A, null),
... //followed by the pre-configured list.Please note, however, that the following call:
mgr.addProviderAtFront(A, m3)
does not subsume the previous setting of (A, null) and the list will
effectively become {(A, m3), (B, null), (A, null), ...}p - the provider instance that should be used whenever support
is needed for mech.mech - the mechanism for which the provider is being setGSSException - containing the following
major error codes:
GSSException.UNAVAILABLE,
GSSException.FAILUREpublic abstract void addProviderAtEnd(Provider p, Oid mech) throws GSSException
Calling this method repeatedly preserves the older settings but raises them above newer ones in preference thus forming an ordered list of providers and Oid pairs that grows at the bottom. Thus the older provider settings will be utilized first before this one is.
If there are any previously existing preferences that conflict with the preference being set here, then the GSSManager should ignore this request.
If the GSSManager implementation does not support an SPI with a pluggable provider architecture it should throw a GSSException with the status code GSSException.UNAVAILABLE to indicate that the operation is unavailable.
Suppose an application desired that when a mechanism of Oid m1 is needed the system default providers always be checked first, and only when they do not support m1 should a provider A be checked. It would then make the call:
GSSManager mgr = GSSManager.getInstance();
mgr.addProviderAtEnd(A, m1);
Now, if it also desired that for all mechanisms the provider B be
checked after all configured providers have been checked, it would
then call:
mgr.addProviderAtEnd(B, null);
Effectively the list of preferences now becomes {..., (A, m1), (B,
null)}.Suppose at a later time the following call is made to the same GSSManager instance:
mgr.addProviderAtEnd(B, m2)
then the previous setting with the pair (B, null) subsumes this and
therefore this request should be ignored. The same would happen if a
request is made for the already existing pairs of (A, m1) or (B,
null).Please note, however, that the following call:
mgr.addProviderAtEnd(A, null)
is not subsumed by the previous setting of (A, m1) and the list will
effectively become {..., (A, m1), (B, null), (A, null)}p - the provider instance that should be used whenever support
is needed for mech.mech - the mechanism for which the provider is being setGSSException - containing the following
major error codes:
GSSException.UNAVAILABLE,
GSSException.FAILURE