/**
* 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.
*/
package org.apache.hadoop.security;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import javax.security.auth.callback.Callback;
import javax.security.auth.callback.CallbackHandler;
import javax.security.auth.callback.NameCallback;
import javax.security.auth.callback.PasswordCallback;
import javax.security.auth.callback.UnsupportedCallbackException;
import javax.security.sasl.RealmCallback;
import javax.security.sasl.RealmChoiceCallback;
import javax.security.sasl.Sasl;
import javax.security.sasl.SaslException;
import javax.security.sasl.SaslClient;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.io.WritableUtils;
import org.apache.hadoop.ipc.RemoteException;
import org.apache.hadoop.security.SaslRpcServer.AuthMethod;
import org.apache.hadoop.security.SaslRpcServer.SaslStatus;
import org.apache.hadoop.security.token.Token;
import org.apache.hadoop.security.token.TokenIdentifier;
/**
* A utility class that encapsulates SASL logic for RPC client
*/
public class SaslRpcClient {
public static final Log LOG = LogFactory.getLog(SaslRpcClient.class);
private final SaslClient saslClient;
private final boolean fallbackAllowed;
/**
* Create a SaslRpcClient for an authentication method
*
* @param method
* the requested authentication method
* @param token
* token to use if needed by the authentication method
*/
public SaslRpcClient(AuthMethod method,
Token<? extends TokenIdentifier> token, String serverPrincipal,
boolean fallbackAllowed)
throws IOException {
this.fallbackAllowed = fallbackAllowed;
switch (method) {
case DIGEST:
if (LOG.isDebugEnabled())
LOG.debug("Creating SASL " + AuthMethod.DIGEST.getMechanismName()
+ " client to authenticate to service at " + token.getService());
saslClient = Sasl.createSaslClient(new String[] { AuthMethod.DIGEST
.getMechanismName() }, null, null, SaslRpcServer.SASL_DEFAULT_REALM,
SaslRpcServer.SASL_PROPS, new SaslClientCallbackHandler(token));
break;
case KERBEROS:
if (LOG.isDebugEnabled()) {
LOG
.debug("Creating SASL " + AuthMethod.KERBEROS.getMechanismName()
+ " client. Server's Kerberos principal name is "
+ serverPrincipal);
}
if (serverPrincipal == null || serverPrincipal.length() == 0) {
throw new IOException(
"Failed to specify server's Kerberos principal name");
}
String names[] = SaslRpcServer.splitKerberosName(serverPrincipal);
if (names.length != 3) {
throw new IOException(
"Kerberos principal name does NOT have the expected hostname part: "
+ serverPrincipal);
}
saslClient = Sasl.createSaslClient(new String[] { AuthMethod.KERBEROS
.getMechanismName() }, null, names[0], names[1],
SaslRpcServer.SASL_PROPS, null);
break;
default:
throw new IOException("Unknown authentication method " + method);
}
if (saslClient == null)
throw new IOException("Unable to find SASL client implementation");
}
private static void readStatus(DataInputStream inStream) throws IOException {
int status = inStream.readInt(); // read status
if (status != SaslStatus.SUCCESS.state) {
throw new RemoteException(WritableUtils.readString(inStream),
WritableUtils.readString(inStream));
}
}
/**
* Do client side SASL authentication with server via the given InputStream
* and OutputStream
*
* @param inS
* InputStream to use
* @param outS
* OutputStream to use
* @return true if connection is set up, or false if needs to switch
* to simple Auth.
* @throws IOException
*/
public boolean saslConnect(InputStream inS, OutputStream outS)
throws IOException {
DataInputStream inStream = new DataInputStream(new BufferedInputStream(inS));
DataOutputStream outStream = new DataOutputStream(new BufferedOutputStream(
outS));
try {
byte[] saslToken = new byte[0];
if (saslClient.hasInitialResponse())
saslToken = saslClient.evaluateChallenge(saslToken);
if (saslToken != null) {
outStream.writeInt(saslToken.length);
outStream.write(saslToken, 0, saslToken.length);
outStream.flush();
if (LOG.isDebugEnabled())
LOG.debug("Have sent token of size " + saslToken.length
+ " from initSASLContext.");
}
if (!saslClient.isComplete()) {
readStatus(inStream);
int len = inStream.readInt();
if (len == SaslRpcServer.SWITCH_TO_SIMPLE_AUTH) {
if (!fallbackAllowed) {
throw new IOException("Server asks us to fall back to SIMPLE " +
"auth, but this client is configured to only allow secure " +
"connections.");
}
if (LOG.isDebugEnabled())
LOG.debug("Server asks us to fall back to simple auth.");
saslClient.dispose();
return false;
}
saslToken = new byte[len];
if (LOG.isDebugEnabled())
LOG.debug("Will read input token of size " + saslToken.length
+ " for processing by initSASLContext");
inStream.readFully(saslToken);
}
while (!saslClient.isComplete()) {
saslToken = saslClient.evaluateChallenge(saslToken);
if (saslToken != null) {
if (LOG.isDebugEnabled())
LOG.debug("Will send token of size " + saslToken.length
+ " from initSASLContext.");
outStream.writeInt(saslToken.length);
outStream.write(saslToken, 0, saslToken.length);
outStream.flush();
}
if (!saslClient.isComplete()) {
readStatus(inStream);
saslToken = new byte[inStream.readInt()];
if (LOG.isDebugEnabled())
LOG.debug("Will read input token of size " + saslToken.length
+ " for processing by initSASLContext");
inStream.readFully(saslToken);
}
}
if (LOG.isDebugEnabled()) {
LOG.debug("SASL client context established. Negotiated QoP: "
+ saslClient.getNegotiatedProperty(Sasl.QOP));
}
return true;
} catch (IOException e) {
try {
saslClient.dispose();
} catch (SaslException ignored) {
// ignore further exceptions during cleanup
}
throw e;
}
}
/**
* Get a SASL wrapped InputStream. Can be called only after saslConnect() has
* been called.
*
* @param in
* the InputStream to wrap
* @return a SASL wrapped InputStream
* @throws IOException
*/
public InputStream getInputStream(InputStream in) throws IOException {
if (!saslClient.isComplete()) {
throw new IOException("Sasl authentication exchange hasn't completed yet");
}
return new SaslInputStream(in, saslClient);
}
/**
* Get a SASL wrapped OutputStream. Can be called only after saslConnect() has
* been called.
*
* @param out
* the OutputStream to wrap
* @return a SASL wrapped OutputStream
* @throws IOException
*/
public OutputStream getOutputStream(OutputStream out) throws IOException {
if (!saslClient.isComplete()) {
throw new IOException("Sasl authentication exchange hasn't completed yet");
}
return new SaslOutputStream(out, saslClient);
}
/** Release resources used by wrapped saslClient */
public void dispose() throws SaslException {
saslClient.dispose();
}
private static class SaslClientCallbackHandler implements CallbackHandler {
private final String userName;
private final char[] userPassword;
public SaslClientCallbackHandler(Token<? extends TokenIdentifier> token) {
this.userName = SaslRpcServer.encodeIdentifier(token.getIdentifier());
this.userPassword = SaslRpcServer.encodePassword(token.getPassword());
}
public void handle(Callback[] callbacks)
throws UnsupportedCallbackException {
NameCallback nc = null;
PasswordCallback pc = null;
RealmCallback rc = null;
for (Callback callback : callbacks) {
if (callback instanceof RealmChoiceCallback) {
continue;
} else if (callback instanceof NameCallback) {
nc = (NameCallback) callback;
} else if (callback instanceof PasswordCallback) {
pc = (PasswordCallback) callback;
} else if (callback instanceof RealmCallback) {
rc = (RealmCallback) callback;
} else {
throw new UnsupportedCallbackException(callback,
"Unrecognized SASL client callback");
}
}
if (nc != null) {
if (LOG.isDebugEnabled())
LOG.debug("SASL client callback: setting username: " + userName);
nc.setName(userName);
}
if (pc != null) {
if (LOG.isDebugEnabled())
LOG.debug("SASL client callback: setting userPassword");
pc.setPassword(userPassword);
}
if (rc != null) {
if (LOG.isDebugEnabled())
LOG.debug("SASL client callback: setting realm: "
+ rc.getDefaultText());
rc.setText(rc.getDefaultText());
}
}
}
}