org.apache.kafka.common.security.oauthbearer.internals.OAuthBearerSaslClientCallbackHandler Maven / Gradle / Ivy
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* 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.kafka.common.security.oauthbearer.internals;
import java.io.IOException;
import java.security.AccessController;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;
import javax.security.auth.Subject;
import javax.security.auth.callback.Callback;
import javax.security.auth.callback.UnsupportedCallbackException;
import javax.security.auth.login.AppConfigurationEntry;
import org.apache.kafka.common.security.auth.SaslExtensionsCallback;
import org.apache.kafka.common.security.auth.AuthenticateCallbackHandler;
import org.apache.kafka.common.security.auth.SaslExtensions;
import org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule;
import org.apache.kafka.common.security.oauthbearer.OAuthBearerToken;
import org.apache.kafka.common.security.oauthbearer.OAuthBearerTokenCallback;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;
/**
* An implementation of {@code AuthenticateCallbackHandler} that recognizes
* {@link OAuthBearerTokenCallback} and retrieves OAuth 2 Bearer Token that was
* created when the {@code OAuthBearerLoginModule} logged in by looking for an
* instance of {@link OAuthBearerToken} in the {@code Subject}'s private
* credentials. This class also recognizes {@link SaslExtensionsCallback} and retrieves any SASL extensions that were
* created when the {@code OAuthBearerLoginModule} logged in by looking for an instance of {@link SaslExtensions}
* in the {@code Subject}'s public credentials
*
* Use of this class is configured automatically and does not need to be
* explicitly set via the {@code sasl.client.callback.handler.class}
* configuration property.
*/
public class OAuthBearerSaslClientCallbackHandler implements AuthenticateCallbackHandler {
private static final Logger log = LogManager.getLogger(OAuthBearerSaslClientCallbackHandler.class);
private boolean configured = false;
/**
* Return true if this instance has been configured, otherwise false
*
* @return true if this instance has been configured, otherwise false
*/
public boolean configured() {
return configured;
}
@Override
public void configure(Map configs, String saslMechanism, List jaasConfigEntries) {
if (!OAuthBearerLoginModule.OAUTHBEARER_MECHANISM.equals(saslMechanism))
throw new IllegalArgumentException(String.format("Unexpected SASL mechanism: %s", saslMechanism));
configured = true;
}
@Override
public void handle(Callback[] callbacks) throws IOException, UnsupportedCallbackException {
if (!configured())
throw new IllegalStateException("Callback handler not configured");
for (Callback callback : callbacks) {
if (callback instanceof OAuthBearerTokenCallback)
handleCallback((OAuthBearerTokenCallback) callback);
else if (callback instanceof SaslExtensionsCallback)
handleCallback((SaslExtensionsCallback) callback, Subject.getSubject(AccessController.getContext()));
else
throw new UnsupportedCallbackException(callback);
}
}
@Override
public void close() {
// empty
}
private void handleCallback(OAuthBearerTokenCallback callback) throws IOException {
if (callback.token() != null)
throw new IllegalArgumentException("Callback had a token already");
Subject subject = Subject.getSubject(AccessController.getContext());
Set privateCredentials = subject != null
? subject.getPrivateCredentials(OAuthBearerToken.class)
: Collections.emptySet();
if (privateCredentials.size() == 0)
throw new IOException("No OAuth Bearer tokens in Subject's private credentials");
if (privateCredentials.size() == 1)
callback.token(privateCredentials.iterator().next());
else {
/*
* There a very small window of time upon token refresh (on the order of milliseconds)
* where both an old and a new token appear on the Subject's private credentials.
* Rather than implement a lock to eliminate this window, we will deal with it by
* checking for the existence of multiple tokens and choosing the one that has the
* longest lifetime. It is also possible that a bug could cause multiple tokens to
* exist (e.g. KAFKA-7902), so dealing with the unlikely possibility that occurs
* during normal operation also allows us to deal more robustly with potential bugs.
*/
SortedSet sortedByLifetime =
new TreeSet<>(
new Comparator() {
@Override
public int compare(OAuthBearerToken o1, OAuthBearerToken o2) {
return Long.compare(o1.lifetimeMs(), o2.lifetimeMs());
}
});
sortedByLifetime.addAll(privateCredentials);
log.warn("Found {} OAuth Bearer tokens in Subject's private credentials; the oldest expires at {}, will use the newest, which expires at {}",
sortedByLifetime.size(),
new Date(sortedByLifetime.first().lifetimeMs()),
new Date(sortedByLifetime.last().lifetimeMs()));
callback.token(sortedByLifetime.last());
}
}
/**
* Attaches the first {@link SaslExtensions} found in the public credentials of the Subject
*/
private static void handleCallback(SaslExtensionsCallback extensionsCallback, Subject subject) {
if (subject != null && !subject.getPublicCredentials(SaslExtensions.class).isEmpty()) {
SaslExtensions extensions = subject.getPublicCredentials(SaslExtensions.class).iterator().next();
extensionsCallback.extensions(extensions);
}
}
}