/*
* $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk/module-client/src/main/java/org/apache/http/impl/auth/DigestScheme.java $
* $Revision: 659595 $
* $Date: 2008-05-23 09:47:14 -0700 (Fri, 23 May 2008) $
*
* ====================================================================
*
* 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.http.impl.auth;
import java.security.MessageDigest;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;
import org.apache.http.Header;
import org.apache.http.HttpRequest;
import org.apache.http.auth.AuthenticationException;
import org.apache.http.auth.Credentials;
import org.apache.http.auth.AUTH;
import org.apache.http.auth.MalformedChallengeException;
import org.apache.http.auth.params.AuthParams;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.message.BasicHeaderValueFormatter;
import org.apache.http.message.BufferedHeader;
import org.apache.http.util.CharArrayBuffer;
import org.apache.http.util.EncodingUtils;
/**
* <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.http.auth.params.AuthPNames#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.http.params.CoreProtocolPNames#HTTP_ELEMENT_CHARSET
* http element charset}.
* </p>
*
* @author <a href="mailto:remm@apache.org">Remy Maucherat</a>
* @author Rodney Waldhoff
* @author <a href="mailto:jsdever@apache.org">Jeff Dever</a>
* @author Ortwin Glueck
* @author Sean C. Sullivan
* @author <a href="mailto:adrian@ephox.com">Adrian Sutton</a>
* @author <a href="mailto:mbowler@GargoyleSoftware.com">Mike Bowler</a>
* @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
*
* @since 4.0
*/
public class DigestScheme extends RFC2617Scheme {
/**
* 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;
/**
* Default constructor for the digest authetication scheme.
*/
public DigestScheme() {
super();
this.complete = false;
}
/**
* Processes the Digest challenge.
*
* @param header the challenge header
*
* @throws MalformedChallengeException is thrown if the authentication challenge
* is malformed
*/
@Override
public void processChallenge(
final Header header) throws MalformedChallengeException {
super.processChallenge(header);
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;
}
}
}
if (unsupportedQop && (qopVariant == QOP_MISSING)) {
throw new MalformedChallengeException("None of the qop methods is supported");
}
// Reset cnonce
this.cnonce = null;
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.
*/
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>.
*/
public boolean isConnectionBased() {
return false;
}
public void overrideParamter(final String name, final String value) {
getParameters().put(name, value);
}
private String getCnonce() {
if (this.cnonce == null) {
this.cnonce = createCnonce();
}
return this.cnonce;
}
/**
* 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 request The request being authenticated
*
* @throws org.apache.http.auth.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
*/
public Header authenticate(
final Credentials credentials,
final HttpRequest request) throws AuthenticationException {
if (credentials == null) {
throw new IllegalArgumentException("Credentials may not be null");
}
if (request == null) {
throw new IllegalArgumentException("HTTP request may not be null");
}
// Add method name and request-URI to the parameter map
getParameters().put("methodname", request.getRequestLine().getMethod());
getParameters().put("uri", request.getRequestLine().getUri());
String charset = getParameter("charset");
if (charset == null) {
charset = AuthParams.getCredentialCharset(request.getParams());
getParameters().put("charset", charset);
}
String digest = createDigest(credentials);
return createDigestHeader(credentials, digest);
}
private static MessageDigest createMessageDigest(
final String digAlg) throws UnsupportedDigestAlgorithmException {
try {
return MessageDigest.getInstance(digAlg);
} catch (Exception e) {
throw new UnsupportedDigestAlgorithmException(
"Unsupported algorithm in HTTP Digest authentication: "
+ digAlg);
}
}
/**
* Creates an MD5 response digest.
*
* @return The created digest as string. This will be the response tag's
* value in the Authentication HTTP header.
* @throws AuthenticationException when MD5 is an unsupported algorithm
*/
private String createDigest(final Credentials credentials) throws AuthenticationException {
// Collecting required tokens
String uri = getParameter("uri");
String realm = getParameter("realm");
String nonce = getParameter("nonce");
String method = getParameter("methodname");
String algorithm = getParameter("algorithm");
if (uri == null) {
throw new IllegalStateException("URI may not be null");
}
if (realm == null) {
throw new IllegalStateException("Realm may not be null");
}
if (nonce == null) {
throw new IllegalStateException("Nonce may not be null");
}
// If an algorithm is not specified, default to MD5.
if (algorithm == null) {
algorithm = "MD5";
}
// If an charset is not specified, default to ISO-8859-1.
String charset = getParameter("charset");
if (charset == null) {
charset = "ISO-8859-1";
}
if (qopVariant == QOP_AUTH_INT) {
throw new AuthenticationException(
"Unsupported qop in HTTP Digest authentication");
}
MessageDigest md5Helper = createMessageDigest("MD5");
String uname = credentials.getUserPrincipal().getName();
String pwd = credentials.getPassword();
// 3.2.2.2: Calculating digest
StringBuilder tmp = new StringBuilder(uname.length() + realm.length() + pwd.length() + 2);
tmp.append(uname);
tmp.append(':');
tmp.append(realm);
tmp.append(':');
tmp.append(pwd);
// unq(username-value) ":" unq(realm-value) ":" passwd
String a1 = tmp.toString();
//a1 is suitable for MD5 algorithm
if(algorithm.equals("MD5-sess")) {
// H( unq(username-value) ":" unq(realm-value) ":" passwd )
// ":" unq(nonce-value)
// ":" unq(cnonce-value)
String cnonce = getCnonce();
String tmp2=encode(md5Helper.digest(EncodingUtils.getBytes(a1, charset)));
StringBuilder tmp3 = new StringBuilder(tmp2.length() + nonce.length() + cnonce.length() + 2);
tmp3.append(tmp2);
tmp3.append(':');
tmp3.append(nonce);
tmp3.append(':');
tmp3.append(cnonce);
a1 = tmp3.toString();
} else if (!algorithm.equals("MD5")) {
throw new AuthenticationException("Unhandled algorithm " + algorithm + " requested");
}
String md5a1 = encode(md5Helper.digest(EncodingUtils.getBytes(a1, charset)));
String a2 = null;
if (qopVariant == QOP_AUTH_INT) {
// Unhandled qop auth-int
//we do not have access to the entity-body or its hash
//TODO: add Method ":" digest-uri-value ":" H(entity-body)
} else {
a2 = method + ':' + uri;
}
String md5a2 = encode(md5Helper.digest(EncodingUtils.getAsciiBytes(a2)));
// 3.2.2.1
String serverDigestValue;
if (qopVariant == QOP_MISSING) {
StringBuilder tmp2 = new StringBuilder(md5a1.length() + nonce.length() + md5a2.length());
tmp2.append(md5a1);
tmp2.append(':');
tmp2.append(nonce);
tmp2.append(':');
tmp2.append(md5a2);
serverDigestValue = tmp2.toString();
} else {
String qopOption = getQopVariantString();
String cnonce = getCnonce();
StringBuilder tmp2 = new StringBuilder(md5a1.length() + nonce.length()
+ NC.length() + cnonce.length() + qopOption.length() + md5a2.length() + 5);
tmp2.append(md5a1);
tmp2.append(':');
tmp2.append(nonce);
tmp2.append(':');
tmp2.append(NC);
tmp2.append(':');
tmp2.append(cnonce);
tmp2.append(':');
tmp2.append(qopOption);
tmp2.append(':');
tmp2.append(md5a2);
serverDigestValue = tmp2.toString();
}
String serverDigest =
encode(md5Helper.digest(EncodingUtils.getAsciiBytes(serverDigestValue)));
return serverDigest;
}
/**
* Creates digest-response header as defined in RFC2617.
*
* @param credentials User credentials
* @param digest The response tag's value as String.
*
* @return The digest-response as String.
*/
private Header createDigestHeader(
final Credentials credentials,
final String digest) throws AuthenticationException {
CharArrayBuffer buffer = new CharArrayBuffer(128);
if (isProxy()) {
buffer.append(AUTH.PROXY_AUTH_RESP);
} else {
buffer.append(AUTH.WWW_AUTH_RESP);
}
buffer.append(": Digest ");
String uri = getParameter("uri");
String realm = getParameter("realm");
String nonce = getParameter("nonce");
String opaque = getParameter("opaque");
String response = digest;
String algorithm = getParameter("algorithm");
String uname = credentials.getUserPrincipal().getName();
List<BasicNameValuePair> params = new ArrayList<BasicNameValuePair>(20);
params.add(new BasicNameValuePair("username", uname));
params.add(new BasicNameValuePair("realm", realm));
params.add(new BasicNameValuePair("nonce", nonce));
params.add(new BasicNameValuePair("uri", uri));
params.add(new BasicNameValuePair("response", response));
if (qopVariant != QOP_MISSING) {
params.add(new BasicNameValuePair("qop", getQopVariantString()));
params.add(new BasicNameValuePair("nc", NC));
params.add(new BasicNameValuePair("cnonce", getCnonce()));
}
if (algorithm != null) {
params.add(new BasicNameValuePair("algorithm", algorithm));
}
if (opaque != null) {
params.add(new BasicNameValuePair("opaque", opaque));
}
for (int i = 0; i < params.size(); i++) {
BasicNameValuePair param = params.get(i);
if (i > 0) {
buffer.append(", ");
}
boolean noQuotes = "nc".equals(param.getName()) ||
"qop".equals(param.getName());
BasicHeaderValueFormatter.DEFAULT
.formatNameValuePair(buffer, param, !noQuotes);
}
return new BufferedHeader(buffer);
}
private String getQopVariantString() {
String qopOption;
if (qopVariant == QOP_AUTH_INT) {
qopOption = "auth-int";
} else {
qopOption = "auth";
}
return qopOption;
}
/**
* Encodes the 128 bit (16 bytes) MD5 digest into a 32 characters long
* <CODE>String</CODE> according to RFC 2617.
*
* @param binaryData array containing the digest
* @return encoded MD5, or <CODE>null</CODE> if encoding failed
*/
private static String encode(byte[] binaryData) {
if (binaryData.length != 16) {
return null;
}
char[] buffer = new char[32];
for (int i = 0; i < 16; i++) {
int low = (binaryData[i] & 0x0f);
int high = ((binaryData[i] & 0xf0) >> 4);
buffer[i * 2] = HEXADECIMAL[high];
buffer[(i * 2) + 1] = HEXADECIMAL[low];
}
return new String(buffer);
}
/**
* Creates a random cnonce value based on the current time.
*
* @return The cnonce value as String.
* @throws UnsupportedDigestAlgorithmException if MD5 algorithm is not supported.
*/
public static String createCnonce() {
String cnonce;
MessageDigest md5Helper = createMessageDigest("MD5");
cnonce = Long.toString(System.currentTimeMillis());
cnonce = encode(md5Helper.digest(EncodingUtils.getAsciiBytes(cnonce)));
return cnonce;
}
}
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