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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
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*
* This code is distributed in the hope that it will be useful, but WITHOUT
* 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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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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package com.sun.security.sasl;
import javax.security.sasl.*;
import java.security.NoSuchAlgorithmException;
import java.util.logging.Logger;
import java.util.logging.Level;
/**
* Implements the CRAM-MD5 SASL client-side mechanism.
* (<A HREF="http://www.ietf.org/rfc/rfc2195.txt">RFC 2195</A>).
* CRAM-MD5 has no initial response. It receives bytes from
* the server as a challenge, which it hashes by using MD5 and the password.
* It concatenates the authentication ID with this result and returns it
* as the response to the challenge. At that point, the exchange is complete.
*
* @author Vincent Ryan
* @author Rosanna Lee
*/
final class CramMD5Client extends CramMD5Base implements SaslClient {
private String username;
/**
* Creates a SASL mechanism with client credentials that it needs
* to participate in CRAM-MD5 authentication exchange with the server.
*
* @param authID A non-null string representing the principal
* being authenticated.
*
* @param pw A non-null String or byte[]
* containing the password. If it is an array, it is first cloned.
*/
CramMD5Client(String authID, byte[] pw) throws SaslException {
if (authID == null || pw == null) {
throw new SaslException(
"CRAM-MD5: authentication ID and password must be specified");
}
username = authID;
this.pw = pw; // caller should have already cloned
}
/**
* CRAM-MD5 has no initial response.
*/
public boolean hasInitialResponse() {
return false;
}
/**
* Processes the challenge data.
*
* The server sends a challenge data using which the client must
* compute an MD5-digest with its password as the key.
*
* @param challengeData A non-null byte array containing the challenge
* data from the server.
* @return A non-null byte array containing the response to be sent to
* the server.
* @throws SaslException If platform does not have MD5 support
* @throw IllegalStateException if this method is invoked more than once.
*/
public byte[] evaluateChallenge(byte[] challengeData)
throws SaslException {
// See if we've been here before
if (completed) {
throw new IllegalStateException(
"CRAM-MD5 authentication already completed");
}
if (aborted) {
throw new IllegalStateException(
"CRAM-MD5 authentication previously aborted due to error");
}
// generate a keyed-MD5 digest from the user's password and challenge.
try {
if (logger.isLoggable(Level.FINE)) {
logger.log(Level.FINE, "CRAMCLNT01:Received challenge: {0}",
new String(challengeData, "UTF8"));
}
String digest = HMAC_MD5(pw, challengeData);
// clear it when we no longer need it
clearPassword();
// response is username + " " + digest
String resp = username + " " + digest;
logger.log(Level.FINE, "CRAMCLNT02:Sending response: {0}", resp);
completed = true;
return resp.getBytes("UTF8");
} catch (java.security.NoSuchAlgorithmException e) {
aborted = true;
throw new SaslException("MD5 algorithm not available on platform", e);
} catch (java.io.UnsupportedEncodingException e) {
aborted = true;
throw new SaslException("UTF8 not available on platform", e);
}
}
}