digestscheme.java

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/*
 * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/auth/DigestScheme.java,v 1.22 2004/12/30 11:01:27 oglueck Exp $
 * $Revision: 480424 $
 * $Date: 2006-11-29 06:56:49 +0100 (Wed, 29 Nov 2006) $
 *
 * ====================================================================
 *
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.commons.httpclient.auth;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;

import org.apache.commons.httpclient.Credentials;
import org.apache.commons.httpclient.HttpClientError;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient.UsernamePasswordCredentials;
import org.apache.commons.httpclient.util.EncodingUtil;
import org.apache.commons.httpclient.util.ParameterFormatter;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * <p>
 * Digest authentication scheme as defined in RFC 2617.
 * Both MD5 (default) and MD5-sess are supported.
 * Currently only qop=auth or no qop is supported. qop=auth-int
 * is unsupported. If auth and auth-int are provided, auth is
 * used.
 * </p>
 * <p>
 * Credential charset is configured via the 
 * {@link org.apache.commons.httpclient.params.HttpMethodParams#CREDENTIAL_CHARSET credential
 * charset} parameter.  Since the digest username is included as clear text in the generated 
 * Authentication header, the charset of the username must be compatible with the 
 * {@link org.apache.commons.httpclient.params.HttpMethodParams#HTTP_ELEMENT_CHARSET http element 
 * charset}.
 * </p>
 * TODO: make class more stateful regarding repeated authentication requests
 * 
 * @author <a href="mailto:[e-mail]">Remy Maucherat</a>
 * @author Rodney Waldhoff
 * @author <a href="mailto:[e-mail]">Jeff Dever</a>
 * @author Ortwin Gl?ck
 * @author Sean C. Sullivan
 * @author <a href="mailto:[e-mail]">Adrian Sutton</a>
 * @author <a href="mailto:[e-mail]">Mike Bowler</a>
 * @author <a href="mailto:[e-mail]">Oleg Kalnichevski</a>
 */

public class DigestScheme extends RFC2617Scheme {
    
    /** Log object for this class. */
    private static final Log LOG = LogFactory.getLog(DigestScheme.class);

    /**
     * Hexa values used when creating 32 character long digest in HTTP DigestScheme
     * in case of authentication.
     * 
     * @see #encode(byte[])
     */
    private static final char[] HEXADECIMAL = {
        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 
        'e', 'f'
    };
    
    /** Whether the digest authentication process is complete */
    private boolean complete;
    
    //TODO: supply a real nonce-count, currently a server will interprete a repeated request as a replay  
    private static final String NC = "00000001"; //nonce-count is always 1
    private static final int QOP_MISSING = 0;
    private static final int QOP_AUTH_INT = 1;
    private static final int QOP_AUTH = 2;

    private int qopVariant = QOP_MISSING;
    private String cnonce;

    private final ParameterFormatter formatter;
    /**
     * Default constructor for the digest authetication scheme.
     * 
     * @since 3.0
     */
    public DigestScheme() {
        super();
        this.complete = false;
        this.formatter = new ParameterFormatter();
    }

    /**
     * Gets an ID based upon the realm and the nonce value.  This ensures that requests
     * to the same realm with different nonce values will succeed.  This differentiation
     * allows servers to request re-authentication using a fresh nonce value.
     * 
     * @deprecated no longer used
     */
    public String getID() {
        
        String id = getRealm();
        String nonce = getParameter("nonce");
        if (nonce != null) {
            id += "-" + nonce;
        }
        
        return id;
    }

    /**
     * Constructor for the digest authetication scheme.
     * 
     * @param challenge authentication challenge
     * 
     * @throws MalformedChallengeException is thrown if the authentication challenge
     * is malformed
     * 
     * @deprecated Use parameterless constructor and {@link AuthScheme#processChallenge(String)} 
     *             method
     */
    public DigestScheme(final String challenge) 
      throws MalformedChallengeException {
        this();
        processChallenge(challenge);
    }

    /**
     * Processes the Digest challenge.
     *  
     * @param challenge the challenge string
     * 
     * @throws MalformedChallengeException is thrown if the authentication challenge
     * is malformed
     * 
     * @since 3.0
     */
    public void processChallenge(final String challenge) 
      throws MalformedChallengeException {
        super.processChallenge(challenge);
        
        if (getParameter("realm") == null) {
            throw new MalformedChallengeException("missing realm in challange");
        }
        if (getParameter("nonce") == null) {
            throw new MalformedChallengeException("missing nonce in challange");   
        }
        
        boolean unsupportedQop = false;
        // qop parsing
        String qop = getParameter("qop");
        if (qop != null) {
            StringTokenizer tok = new StringTokenizer(qop,",");
            while (tok.hasMoreTokens()) {
                String variant = tok.nextToken().trim();
                if (variant.equals("auth")) {
                    qopVariant = QOP_AUTH;
                    break; //that's our favourite, because auth-int is unsupported
                } else if (variant.equals("auth-int")) {
                    qopVariant = QOP_AUTH_INT;               
                } else {
                    unsupportedQop = true;
                    LOG.warn("Unsupported qop detected: "+ variant);   
                }     
            }
        }        
        
        if (unsupportedQop && (qopVariant == QOP_MISSING)) {
            throw new MalformedChallengeException("None of the qop methods is supported");   
        }
        
        cnonce = createCnonce();   
        this.complete = true;
    }

    /**
     * Tests if the Digest authentication process has been completed.
     * 
     * @return <tt>true</tt> if Digest authorization has been processed,
     *   <tt>false</tt> otherwise.
     * 
     * @since 3.0
     */
    public boolean isComplete() {
        String s = getParameter("stale");
        if ("true".equalsIgnoreCase(s)) {
            return false;
        } else {
            return this.complete;
        }
    }

    /**
     * Returns textual designation of the digest authentication scheme.
     * 
     * @return <code>digest</code>
     */
    public String getSchemeName() {
        return "digest";
    }

    /**
     * Returns <tt>false</tt>. Digest authentication scheme is request based.
     * 
     * @return <tt>false</tt>.
     * 
     * @since 3.0
     */
    public boolean isConnectionBased() {
        return false;    
    }

    /**
     * Produces a digest authorization string for the given set of 
     * {@link Credentials}, method name and URI.
     * 
     * @param credentials A set of credentials to be used for athentication
     * @param method the name of the method that requires authorization. 
     * @param uri The URI for which authorization is needed. 
     * 
     * @throws InvalidCredentialsException if authentication credentials
     *         are not valid or not applicable for this authentication scheme
     * @throws AuthenticationException if authorization string cannot 
     *   be generated due to an authentication failure
     * 
     * @return a digest authorization string
     * 
     * @see org.apache.commons.httpclient.HttpMethod#getName()
     * @see org.apache.commons.httpclient.HttpMethod#getPath()
     * 
     * @deprecated Use {@link #authenticate(Credentials, HttpMethod)}
     */
    public String authenticate(Credentials credentials, String method, String uri)
      throws AuthenticationException {

        LOG.trace("enter DigestScheme.authenticate(Credentials, String, String)");

        UsernamePasswordCredentials usernamepassword = null;
        try {
            usernamepassword = (UsernamePasswordCredentials) credentials;
        } catch (ClassCastException e) {
            throw new InvalidCredentialsException(
             "Credentials cannot be used for digest authentication: " 
              + credentials.getClass().getName());
        }
        getParameters().put("methodname", method);
        getParameters().put("uri", uri);
        String digest = createDigest(
            usernamepassword.getUserName(),
            usernamepassword.getPassword());
        return "Digest " + createDigestHeader(usernamepassword.getUserName(), digest);
    }

    /**
     * Produces a digest authorization string for the given set of 
     * {@link Credentials}, method name and URI.
     * 
     * @param credentials A set of credentials to be used for athentication
     * @param method The method being authenticated
     * 
     * @throws InvalidCredentialsException if authentication credentials
     *         are not valid or not applicable for this authentication scheme