| /* |
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| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
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| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
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| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * 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 client. |
| *<p> |
| * 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 <tt>SaslClient</tt> instance |
| * process challenges and create responses according to the SASL |
| * mechanism implemented by the <tt>SaslClient</tt>. |
| * As the authentication proceeds, the instance |
| * encapsulates the state of a SASL client's authentication exchange. |
| *<p> |
| * Here's an example of how an LDAP library might use a <tt>SaslClient</tt>. |
| * It first gets an instance of a <tt>SaslClient</tt>: |
| *<blockquote><pre> |
| * SaslClient sc = Sasl.createSaslClient(mechanisms, |
| * authorizationId, protocol, serverName, props, callbackHandler); |
| *</pre></blockquote> |
| * It can then proceed to use the client for authentication. |
| * For example, an LDAP library might use the client as follows: |
| *<blockquote><pre> |
| * // 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); |
| * } |
| * } |
| *</pre></blockquote> |
| * |
| * If the mechanism has an initial response, the library invokes |
| * <tt>evaluateChallenge()</tt> with an empty |
| * challenge and to get initial response. |
| * Protocols such as IMAP4, which do not include an initial response with |
| * their first authentication command to the server, initiates the |
| * authentication without first calling <tt>hasInitialResponse()</tt> |
| * or <tt>evaluateChallenge()</tt>. |
| * 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 <tt>evaluateChallenge()</tt> with an empty challenge. |
| * |
| * @since 1.5 |
| * |
| * @see Sasl |
| * @see SaslClientFactory |
| * |
| * @author Rosanna Lee |
| * @author Rob Weltman |
| */ |
| public abstract interface SaslClient { |
| |
| /** |
| * Returns the IANA-registered mechanism name of this SASL client. |
| * (e.g. "CRAM-MD5", "GSSAPI"). |
| * @return A non-null string representing the IANA-registered mechanism name. |
| */ |
| public abstract String getMechanismName(); |
| |
| /** |
| * Determines whether this mechanism has an optional initial response. |
| * If true, caller should call <tt>evaluateChallenge()</tt> with an |
| * empty array to get the initial response. |
| * |
| * @return true if this mechanism has an initial response. |
| */ |
| public abstract boolean hasInitialResponse(); |
| |
| /** |
| * Evaluates the challenge data and generates a response. |
| * If a challenge is received from the server during the authentication |
| * process, this method is called to prepare an appropriate next |
| * response to submit to the server. |
| * |
| * @param challenge The non-null challenge sent from the server. |
| * The challenge array may have zero length. |
| * |
| * @return 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. |
| * @exception SaslException If an error occurred while processing |
| * the challenge or generating a response. |
| */ |
| public abstract byte[] evaluateChallenge(byte[] challenge) |
| throws SaslException; |
| |
| /** |
| * Determines whether the authentication exchange has completed. |
| * This method may be called at any time, but typically, it |
| * will not be called until the caller has received indication |
| * from the server |
| * (in a protocol-specific manner) that the exchange has completed. |
| * |
| * @return true if the authentication exchange has completed; false otherwise. |
| */ |
| public abstract boolean isComplete(); |
| |
| /** |
| * Unwraps a byte array received from the server. |
| * 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 server. |
| * @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 server. |
| * 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> |
| * 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 non-null property name. |
| * @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 SaslClient might be using. Invoking this method invalidates |
| * the SaslClient instance. This method is idempotent. |
| * @throws SaslException If a problem was encountered while disposing |
| * the resources. |
| */ |
| public abstract void dispose() throws SaslException; |
| } |