// YaCyDigestScheme.java
// Copyright 2017 by luccioman; https://github.com/luccioman
//
// This is a part of YaCy, a peer-to-peer based web search engine
//
// LICENSE
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program 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 for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package net.yacy.cora.protocol.http.auth;
import java.io.IOException;
import java.nio.charset.Charset;
import java.security.MessageDigest;
import java.security.SecureRandom;
import java.util.ArrayList;
import java.util.Formatter;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Set;
import java.util.StringTokenizer;
import org.apache.http.Consts;
import org.apache.http.Header;
import org.apache.http.HttpEntity;
import org.apache.http.HttpEntityEnclosingRequest;
import org.apache.http.HttpRequest;
import org.apache.http.auth.AUTH;
import org.apache.http.auth.AuthenticationException;
import org.apache.http.auth.Credentials;
import org.apache.http.auth.params.AuthPNames;
import org.apache.http.impl.auth.DigestScheme;
import org.apache.http.impl.auth.UnsupportedDigestAlgorithmException;
import org.apache.http.message.BasicHeaderValueFormatter;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.message.BufferedHeader;
import org.apache.http.protocol.HttpContext;
import org.apache.http.util.Args;
import org.apache.http.util.CharArrayBuffer;
import org.apache.http.util.EncodingUtils;
/**
* Overrides the Apache DigestScheme to support credentials with YaCy encoded
* passwords instead of clear-text ones. This implementation is directly derived
* from the {@link DigestScheme} from Apache HTTPClient 4.5.3.
*/
public class YaCyDigestScheme extends DigestScheme {
private static final long serialVersionUID = 3883908186234566916L;
/**
* 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;
private static final int QOP_UNKNOWN = -1;
private static final int QOP_MISSING = 0;
private static final int QOP_AUTH_INT = 1;
private static final int QOP_AUTH = 2;
private String lastNonce;
private long nounceCount;
private String cnonce;
private String a2;
/**
* @since 4.3
*/
public YaCyDigestScheme(final Charset credentialsCharset) {
super(credentialsCharset);
this.complete = false;
}
public YaCyDigestScheme() {
this(Consts.ASCII);
}
/**
* Produces a digest authorization string for the given set of
* {@link Credentials}, method name and URI. The credentials password is
* supposed to be a YaCy encoded password (see adminAccountBase64MD5
* property in yacy.conf) and not a clear-text value.
*
* @param credentials
* A set of credentials to be used for authentication
* @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
*/
@Override
public Header authenticate(
final Credentials credentials,
final HttpRequest request,
final HttpContext context) throws AuthenticationException {
Args.notNull(credentials, "Credentials");
Args.notNull(request, "HTTP request");
if (getParameter("realm") == null) {
throw new AuthenticationException("missing realm in challenge");
}
if (getParameter("nonce") == null) {
throw new AuthenticationException("missing nonce in challenge");
}
// Add method name and request-URI to the parameter map
getParameters().put("methodname", request.getRequestLine().getMethod());
getParameters().put("uri", request.getRequestLine().getUri());
final String charset = getParameter("charset");
if (charset == null) {
getParameters().put("charset", getCredentialsCharset(request));
}
return createDigestHeader(credentials, request);
}
String getCredentialsCharset(final HttpRequest request) {
String charset = (String) request.getParams().getParameter(AuthPNames.CREDENTIAL_CHARSET);
if (charset == null) {
charset = getCredentialsCharset().name();
}
return charset;
}
private static MessageDigest createMessageDigest(
final String digAlg) throws UnsupportedDigestAlgorithmException {
try {
return MessageDigest.getInstance(digAlg);
} catch (final Exception e) {
throw new UnsupportedDigestAlgorithmException(
"Unsupported algorithm in HTTP Digest authentication: "
+ digAlg);
}
}
/**
* Creates digest-response header as defined in RFC2617.
*
* @param credentials User credentials
*
* @return The digest-response as String.
*/
private Header createDigestHeader(
final Credentials credentials,
final HttpRequest request) throws AuthenticationException {
final String uri = getParameter("uri");
final String realm = getParameter("realm");
final String nonce = getParameter("nonce");
final String opaque = getParameter("opaque");
final String method = getParameter("methodname");
String algorithm = getParameter("algorithm");
// If an algorithm is not specified, default to MD5.
if (algorithm == null) {
algorithm = "MD5";
}
final Set<String> qopset = new HashSet<String>(8);
int qop = QOP_UNKNOWN;
final String qoplist = getParameter("qop");
if (qoplist != null) {
final StringTokenizer tok = new StringTokenizer(qoplist, ",");
while (tok.hasMoreTokens()) {
final String variant = tok.nextToken().trim();
qopset.add(variant.toLowerCase(Locale.ROOT));
}
if (request instanceof HttpEntityEnclosingRequest && qopset.contains("auth-int")) {
qop = QOP_AUTH_INT;
} else if (qopset.contains("auth")) {
qop = QOP_AUTH;
}
} else {
qop = QOP_MISSING;
}
if (qop == QOP_UNKNOWN) {
throw new AuthenticationException("None of the qop methods is supported: " + qoplist);
}
String charset = getParameter("charset");
if (charset == null) {
charset = "ISO-8859-1";
}
String digAlg = algorithm;
if (digAlg.equalsIgnoreCase("MD5-sess")) {
digAlg = "MD5";
}
final MessageDigest digester;
try {
digester = createMessageDigest(digAlg);
} catch (final UnsupportedDigestAlgorithmException ex) {
throw new AuthenticationException("Unsuppported digest algorithm: " + digAlg);
}
final String uname = credentials.getUserPrincipal().getName();
/* Modification for YaCy Digest authentication using the encoded password from yacy.conf */
String pwd = credentials.getPassword();
if(pwd.startsWith("MD5:")) {
pwd = pwd.substring("MD5:".length());
}
if (nonce.equals(this.lastNonce)) {
nounceCount++;
} else {
nounceCount = 1;
cnonce = null;
lastNonce = nonce;
}
final StringBuilder sb = new StringBuilder(256);
final Formatter formatter = new Formatter(sb, Locale.US);
formatter.format("%08x", Long.valueOf(nounceCount));
formatter.close();
final String nc = sb.toString();
if (cnonce == null) {
cnonce = createCnonce();
}
a2 = null;
// 3.2.2.2: Calculating digest
String hasha1 ;
if (algorithm.equalsIgnoreCase("MD5-sess")) {
// H( unq(username-value) ":" unq(realm-value) ":" passwd )
// ":" unq(nonce-value)
// ":" unq(cnonce-value)
// calculated one per session
sb.setLength(0);
/* Modification for YaCy Digest Authentication : the pwd value is already the result of MD5(userName:realm:password)
sb.append(uname).append(':').append(realm).append(':').append(pwd);
final String checksum = encode(digester.digest(EncodingUtils.getBytes(sb.toString(), charset)));
sb.setLength(0);
sb.append(checksum).append(':').append(nonce).append(':').append(cnonce);
a1 = sb.toString();*/
sb.append(pwd).append(':').append(nonce).append(':').append(cnonce);
hasha1 = encode(digester.digest(EncodingUtils.getBytes(sb.toString(), charset)));;
} else {
// unq(username-value) ":" unq(realm-value) ":" passwd
/* Modification for YaCy Digest Authentication : the pwd value is already the result of MD5(userName:realm:password)
sb.setLength(0);
sb.append(uname).append(':').append(realm).append(':').append(pwd);
a1 = sb.toString();*/
hasha1 = pwd;
}
/*Modification for YaCy Digest Authentication
final String hasha1 = encode(digester.digest(EncodingUtils.getBytes(a1, charset)));*/
if (qop == QOP_AUTH) {
// Method ":" digest-uri-value
a2 = method + ':' + uri;
} else if (qop == QOP_AUTH_INT) {
// Method ":" digest-uri-value ":" H(entity-body)
HttpEntity entity = null;
if (request instanceof HttpEntityEnclosingRequest) {
entity = ((HttpEntityEnclosingRequest) request).getEntity();
}
if (entity != null && !entity.isRepeatable()) {
// If the entity is not repeatable, try falling back onto QOP_AUTH
if (qopset.contains("auth")) {
qop = QOP_AUTH;
a2 = method + ':' + uri;
} else {
throw new AuthenticationException("Qop auth-int cannot be used with " +
"a non-repeatable entity");
}
} else {
final HttpEntityDigester entityDigester = new HttpEntityDigester(digester);
try {
if (entity != null) {
entity.writeTo(entityDigester);
}
entityDigester.close();
} catch (final IOException ex) {
throw new AuthenticationException("I/O error reading entity content", ex);
}
a2 = method + ':' + uri + ':' + encode(entityDigester.getDigest());
}
} else {
a2 = method + ':' + uri;
}
final String hasha2 = encode(digester.digest(EncodingUtils.getBytes(a2, charset)));
// 3.2.2.1
final String digestValue;
if (qop == QOP_MISSING) {
sb.setLength(0);
sb.append(hasha1).append(':').append(nonce).append(':').append(hasha2);
digestValue = sb.toString();
} else {
sb.setLength(0);
sb.append(hasha1).append(':').append(nonce).append(':').append(nc).append(':')
.append(cnonce).append(':').append(qop == QOP_AUTH_INT ? "auth-int" : "auth")
.append(':').append(hasha2);
digestValue = sb.toString();
}
final String digest = encode(digester.digest(EncodingUtils.getAsciiBytes(digestValue)));
final CharArrayBuffer buffer = new CharArrayBuffer(128);
if (isProxy()) {
buffer.append(AUTH.PROXY_AUTH_RESP);
} else {
buffer.append(AUTH.WWW_AUTH_RESP);
}
buffer.append(": Digest ");
final 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", digest));
if (qop != QOP_MISSING) {
params.add(new BasicNameValuePair("qop", qop == QOP_AUTH_INT ? "auth-int" : "auth"));
params.add(new BasicNameValuePair("nc", nc));
params.add(new BasicNameValuePair("cnonce", cnonce));
}
// algorithm cannot be null here
params.add(new BasicNameValuePair("algorithm", algorithm));
if (opaque != null) {
params.add(new BasicNameValuePair("opaque", opaque));
}
for (int i = 0; i < params.size(); i++) {
final BasicNameValuePair param = params.get(i);
if (i > 0) {
buffer.append(", ");
}
final String name = param.getName();
final boolean noQuotes = ("nc".equals(name) || "qop".equals(name)
|| "algorithm".equals(name));
BasicHeaderValueFormatter.INSTANCE.formatNameValuePair(buffer, param, !noQuotes);
}
return new BufferedHeader(buffer);
}
/**
* 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
*/
static String encode(final byte[] binaryData) {
final int n = binaryData.length;
final char[] buffer = new char[n * 2];
for (int i = 0; i < n; i++) {
final int low = (binaryData[i] & 0x0f);
final 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.
*/
public static String createCnonce() {
final SecureRandom rnd = new SecureRandom();
final byte[] tmp = new byte[8];
rnd.nextBytes(tmp);
return encode(tmp);
}
@Override
public String toString() {
final StringBuilder builder = new StringBuilder();
builder.append("DIGEST [complete=").append(complete)
.append(", nonce=").append(lastNonce)
.append(", nc=").append(nounceCount)
.append("]");
return builder.toString();
}
}