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*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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package javax.security.sasl;
/**
* Performs SASL authentication as a server.
*<p>
* A server such an LDAP server gets an instance of this
* class in order to perform authentication defined by a specific SASL
* mechanism. Invoking methods on the <tt>SaslServer</tt> instance
* generates challenges according to the SASL
* mechanism implemented by the <tt>SaslServer</tt>.
* As the authentication proceeds, the instance
* encapsulates the state of a SASL server's authentication exchange.
*<p>
* Here's an example of how an LDAP server might use a <tt>SaslServer</tt>.
* It first gets an instance of a <tt>SaslServer</tt> for the SASL mechanism
* requested by the client:
*<blockquote><pre>
* SaslServer ss = Sasl.createSaslServer(mechanism,
* "ldap", myFQDN, props, callbackHandler);
*</pre></blockquote>
* 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:
*<blockquote><pre>
* 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);
* }
* }
*</pre></blockquote>
*
* @since 1.5
*
* @see Sasl
* @see SaslServerFactory
*
* @author Rosanna Lee
* @author Rob Weltman
*/
public abstract interface SaslServer {
/**
* Returns the IANA-registered mechanism name of this SASL server.
* (e.g. "CRAM-MD5", "GSSAPI").
* @return A non-null string representing the IANA-registered mechanism name.
*/
public abstract String getMechanismName();
/**
* 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.
* <tt>isComplete()</tt> should be called
* after each call to <tt>evaluateResponse()</tt>,to determine if any further
* response is needed from the client.
*
* @param response The non-null (but possibly empty) response sent
* by the client.
*
* @return 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.
* @exception SaslException If an error occurred while processing
* the response or generating a challenge.
*/
public abstract byte[] evaluateResponse(byte[] response)
throws SaslException;
/**
* Determines whether the authentication exchange has completed.
* This method is typically called after each invocation of
* <tt>evaluateResponse()</tt> to determine whether the
* authentication has completed successfully or should be continued.
* @return true if the authentication exchange has completed; false otherwise.
*/
public abstract boolean isComplete();
/**
* Reports the authorization ID in effect for the client of this
* session.
* This method can only be called if isComplete() returns true.
* @return The authorization ID of the client.
* @exception IllegalStateException if this authentication session has not completed
*/
public String getAuthorizationID();
/**
* Unwraps a byte array received from the client.
* This method can be called only after the authentication exchange has
* completed (i.e., when <tt>isComplete()</tt> returns true) and only if
* the authentication exchange has negotiated integrity and/or privacy
* as the quality of protection; otherwise,
* an <tt>IllegalStateException</tt> is thrown.
*<p>
* <tt>incoming</tt> is the contents of the SASL buffer as defined in RFC 2222
* without the leading four octet field that represents the length.
* <tt>offset</tt> and <tt>len</tt> specify the portion of <tt>incoming</tt>
* to use.
*
* @param incoming A non-null byte array containing the encoded bytes
* from the client.
* @param offset The starting position at <tt>incoming</tt> of the bytes to use.
* @param len The number of bytes from <tt>incoming</tt> to use.
* @return A non-null byte array containing the decoded bytes.
* @exception SaslException if <tt>incoming</tt> cannot be successfully
* unwrapped.
* @exception IllegalStateException if the authentication exchange has
* not completed, or if the negotiated quality of protection
* has neither integrity nor privacy
*/
public abstract byte[] unwrap(byte[] incoming, 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 <tt>isComplete()</tt> returns true) and only if
* the authentication exchange has negotiated integrity and/or privacy
* as the quality of protection; otherwise, a <tt>SaslException</tt> is thrown.
*<p>
* 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.
* <tt>offset</tt> and <tt>len</tt> specify the portion of <tt>outgoing</tt>
* to use.
*
* @param outgoing A non-null byte array containing the bytes to encode.
* @param offset The starting position at <tt>outgoing</tt> of the bytes to use.
* @param len The number of bytes from <tt>outgoing</tt> to use.
* @return A non-null byte array containing the encoded bytes.
* @exception SaslException if <tt>outgoing</tt> cannot be successfully
* wrapped.
* @exception IllegalStateException if the authentication exchange has
* not completed, or if the negotiated quality of protection has
* neither integrity nor privacy.
*/
public abstract byte[] wrap(byte[] outgoing, int offset, int len)
throws SaslException;
/**
* Retrieves the negotiated property.
* This method can be called only after the authentication exchange has
* completed (i.e., when <tt>isComplete()</tt> returns true); otherwise, an
* <tt>IllegalStateException</tt> is thrown.
*
* @param propName the property
* @return The value of the negotiated property. If null, the property was
* not negotiated or is not applicable to this mechanism.
* @exception IllegalStateException if this authentication exchange has not completed
*/
public abstract Object getNegotiatedProperty(String propName);
/**
* 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
* the resources.
*/
public abstract void dispose() throws SaslException;
}