javax.security.sasl
Interface SaslServer

public interface SaslServer

Performs SASL authentication as a server.

A server such as an LDAP server gets an instance of this class in order to perform authentication defined by a specific SASL mechanism. Invoking methods on the SaslServer instance generates challenges corresponding to the SASL mechanism implemented by the SaslServer instance. As the authentication proceeds, the instance encapsulates the state of a SASL server's authentication exchange.

Here's an example of how an LDAP server might use a SaslServer instance. It first gets an instance of a SaslServer for the SASL mechanism requested by the client:

 SaslServer ss = Sasl.createSaslServer( mechanism,
                                        "ldap",
                                        myFQDN,
                                        props,
                                        callbackHandler );

It can then proceed to use the server for authentication. For example, suppose the LDAP server received an LDAP BIND request containing the name of the SASL mechanism and an (optional) initial response. It then might use the server as follows:

 while ( !ss.isComplete() ) {
     try {
         byte[] challenge = ss.evaluateResponse( response );
         if ( ss.isComplete() ) {
             status = ldap.sendBindResponse( mechanism,
                                             challenge,
                                             SUCCESS );
         } else {
             status = ldap.sendBindResponse( mechanism,
                                             challenge,
                                             SASL_BIND_IN_PROGRESS);
             response = ldap.readBindRequest();
         }
     } catch ( SaslException e ) {
         status = ldap.sendErrorResponse( e );
         break;
     }
 }
 if ( ss.isComplete() && (status == SUCCESS) ) {
    String qop = (String)sc.getNegotiatedProperty( Sasl.QOP );
    if ( (qop != null) &&
         (qop.equalsIgnoreCase("auth-int") ||
          qop.equalsIgnoreCase("auth-conf")) ) {

        // Use SaslServer.wrap() and SaslServer.unwrap() for future
        // communication with client
        ldap.in = new SecureInputStream( ss, ldap.in );
        ldap.out = new SecureOutputStream( ss, ldap.out );
    }
 }

See Also:

Sasl, SaslServerFactory

Method Summary

void	dispose() Disposes of any system resources or security-sensitive information the SaslServer might be using.
byte[]	evaluateResponse(byte[] response) Evaluates the response data and generates a challenge.
String	getAuthorizationID() Reports the authorization ID in effect for the client of this session This method can only be called if isComplete() returns true
String	getMechanismName() Returns the IANA-registered mechanism name of this SASL server (e.g.
Object	getNegotiatedProperty(String propName) Retrieves the negotiated property.
boolean	isComplete() Determines if the authentication exchange has completed.
byte[]	unwrap(byte[] incoming, int offset, int len) Unwraps a byte array received from the client.
byte[]	wrap(byte[] outgoing, int offset, int len) Wraps a byte array to be sent to the client.

Method Detail

getMechanismName

public String getMechanismName()

Returns the IANA-registered mechanism name of this SASL server (e.g. "CRAM-MD5", "GSSAPI")

Returns:

A non-null string representing the IANA-registered mechanism name

evaluateResponse

public byte[] evaluateResponse(byte[] response)
                        throws SaslException

Evaluates the response data and generates a challenge. If a response is received from the client during the authentication process, this method is called to prepare an appropriate next challenge to submit to the client. The challenge is null if the authentication has succeeded and no more challenge data is to be sent to the client. It is non-null if the authentication must be continued by sending a challenge to the client, or if the authentication has succeeded but challenge data needs to be processed by the client. isComplete() should be called after each call to evaluateResponse(),to determine if any further response is needed from the client.

Parameters:

response - The non-null (but possibly empty) response sent by the client

Returns:

The possibly null challenge to send to the client. It is null if the authentication has succeeded and there is no more challenge data to be sent to the client.

Throws:

SaslException - if an error occurred while processing the response or generating a challenge

isComplete

public boolean isComplete()

Determines if the authentication exchange has completed. This method is typically called after each invocation of evaluateResponse() to determine whether the authentication has completed successfully or should be continued.

Returns:

true if the authentication exchange has completed; false otherwise.

getAuthorizationID

public String getAuthorizationID()

Reports the authorization ID in effect for the client of this session This method can only be called if isComplete() returns true

Returns:

The authorization ID of the client

Throws:

IllegalStateException - if this authentication session has not completed

unwrap

public byte[] unwrap(byte[] incoming,
                     int offset,
                     int len)
              throws SaslException

Unwraps a byte array received from the client. This method can be called only after the authentication exchange has completed (i.e., when isComplete() returns true) and only if the authentication exchange has negotiated integrity and/or privacy as the quality of protection; otherwise, an 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 client

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

wrap

public byte[] wrap(byte[] outgoing,
                   int offset,
                   int len)
            throws SaslException

Wraps a byte array to be sent to the client. This method can be called only after the authentication exchange has completed (i.e., when isComplete() returns true) and only if the authentication exchange has negotiated integrity and/or privacy as the quality of protection; otherwise, an 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.

getNegotiatedProperty

public Object getNegotiatedProperty(String propName)

Retrieves the negotiated property. This method can be called only after the authentication exchange has completed (i.e., when isComplete() returns true); otherwise, an IllegalStateException is thrown.

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

dispose

public void dispose()
             throws SaslException

Disposes of any system resources or security-sensitive information the SaslServer might be using. Invoking this method invalidates the SaslServer instance. This method is idempotent.

Throws:

SaslException - if a problem was encountered while disposing of the resources.