javax.security.sasl
public interface SaslClient
Performs SASL authentication as a client.
A protocol library such as one for LDAP gets an instance of this class in
order to perform authentication defined by a specific SASL mechanism.
Invoking methods on the SaslClient instance process challenges
and create responses according to the SASL mechanism implemented by the
SaslClient. As the authentication proceeds, the instance
encapsulates the state of a SASL client's authentication exchange.
Here's an example of how an LDAP library might use a SaslClient.
It first gets an instance of a SaslClient:
SaslClient sc =
Sasl.createSaslClient(mechanisms, authorizationID, protocol,
serverName, props, callbackHandler);
It can then proceed to use the client for authentication. For example, an LDAP library might use the client as follows:
// Get initial response and send to server
byte[] response = sc.hasInitialResponse()
? sc.evaluateChallenge(new byte[0]) : null;
LdapResult res = ldap.sendBindRequest(dn, sc.getName(), response);
while (!sc.isComplete()
&& ((res.status == SASL_BIND_IN_PROGRESS) || (res.status == SUCCESS))) {
response = sc.evaluateChallenge( res.getBytes() );
if (res.status == SUCCESS) {
// we're done; don't expect to send another BIND
if ( response != null ) {
throw new SaslException(
"Protocol error: attempting to send response after completion");
}
break;
}
res = ldap.sendBindRequest(dn, sc.getName(), response);
}
if (sc.isComplete() && (res.status == SUCCESS) ) {
String qop = (String)sc.getNegotiatedProperty(Sasl.QOP);
if ((qop != null)
&& (qop.equalsIgnoreCase("auth-int")
|| qop.equalsIgnoreCase("auth-conf"))) {
// Use SaslClient.wrap() and SaslClient.unwrap() for future
// communication with server
ldap.in = new SecureInputStream(sc, ldap.in);
ldap.out = new SecureOutputStream(sc, ldap.out);
}
}
If the mechanism has an initial response, the library invokes {@link #evaluateChallenge(byte[])} with an empty challenge to get the initial response. Protocols such as IMAP4, which do not include an initial response with their first authentication command to the server, initiate the authentication without first calling {@link #hasInitialResponse()} or {@link #evaluateChallenge(byte[])}. When the server responds to the command, it sends an initial challenge. For a SASL mechanism in which the client sends data first, the server should have issued a challenge with no data. This will then result in a call (on the client) to {@link #evaluateChallenge(byte[])} with an empty challenge.
Since: 1.5
See Also: Sasl
| Method Summary | |
|---|---|
| void | dispose()
Disposes of any system resources or security-sensitive information the
SaslClient might be using. |
| byte[] | evaluateChallenge(byte[] challenge)
Evaluates the challenge data and generates a response. |
| String | getMechanismName()
Returns the IANA-registered mechanism name of this SASL client. (e.g.
|
| Object | getNegotiatedProperty(String propName)
Retrieves the negotiated property. |
| boolean | hasInitialResponse()
Determines if this mechanism has an optional initial response. |
| boolean | isComplete()
Determines if the authentication exchange has completed. |
| byte[] | unwrap(byte[] incoming, int offset, int len) Unwraps a byte array received from the server. |
| byte[] | wrap(byte[] outgoing, int offset, int len) Wraps a byte array to be sent to the server. |
SaslClient might be using. Invoking this method invalidates
the SaslClient instance. This method is idempotent.
Throws: SaslException if a problem was encountered while disposing of the resources.
Parameters: challenge the non-null challenge sent from the server. The challenge array may have zero length.
Returns: the possibly null reponse to send to the server. It
is null if the challenge accompanied a "SUCCESS" status and
the challenge only contains data for the client to update its state and no
response needs to be sent to the server. The response is a zero-length
byte array if the client is to send a response with no data.
Throws: SaslException if an error occurred while processing the challenge or generating a response.
Returns: a non-null string representing the IANA-registered mechanism name.
true); otherwise, an {@link IllegalStateException} is
thrown.
Parameters: propName the non-null property name.
Returns: the value of the negotiated property. If null, the
property was not negotiated or is not applicable to this mechanism.
Throws: IllegalStateException if this authentication exchange has not completed.
true, caller should call {@link #evaluateChallenge(byte[])}
with an empty array to get the initial response.
Returns: true if this mechanism has an initial response.
Returns: true if the authentication exchange has completed;
false otherwise.
Unwraps a byte array received from the server. This method can be
called only after the authentication exchange has completed (i.e., when
{@link #isComplete()} returns true) and only if the
authentication exchange has negotiated integrity and/or privacy as the
quality of protection; otherwise, an {@link IllegalStateException} is
thrown.
incoming is the contents of the SASL buffer as defined in
RFC 2222 without the leading four octet field that represents the length.
offset and len specify the portion of incoming
to use.
Parameters: incoming a non-null byte array containing the encoded bytes from
the server. offset the starting position at incoming of the bytes
to use. len the number of bytes from incoming to use.
Returns: a non-null byte array containing the decoded bytes.
Throws: SaslException if incoming cannot be successfully
unwrapped. IllegalStateException if the authentication exchange has not
completed, or if the negotiated quality of protection has neither
integrity nor privacy.
Wraps a byte array to be sent to the server. This method can be called
only after the authentication exchange has completed (i.e., when
{@link #isComplete()} returns true) and only if the
authentication exchange has negotiated integrity and/or privacy as the
quality of protection; otherwise, an {@link IllegalStateException} is
thrown.
The result of this method will make up the contents of the SASL buffer
as defined in RFC 2222 without the leading four octet field that
represents the length. offset and len specify
the portion of outgoing to use.
Parameters: outgoing a non-null byte array containing the bytes to encode. offset the starting position at outgoing of the bytes
to use. len the number of bytes from outgoing to use.
Returns: a non-null byte array containing the encoded bytes.
Throws: SaslException if outgoing cannot be successfully
wrapped. IllegalStateException if the authentication exchange has not
completed, or if the negotiated quality of protection has neither
integrity nor privacy.