org.newsclub.net.unix.ssl.SNIHostnameCapture Maven / Gradle / Ivy
/*
* junixsocket
*
* Copyright 2009-2024 Christian Kohlschütter
*
* Licensed 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.newsclub.net.unix.ssl;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.function.Consumer;
import java.util.function.Supplier;
import javax.net.ssl.ExtendedSSLSession;
import javax.net.ssl.SNIHostName;
import javax.net.ssl.SNIMatcher;
import javax.net.ssl.SNIServerName;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.StandardConstants;
import com.kohlschutter.annotations.compiletime.SuppressFBWarnings;
/**
* Helper class to simplify retrieving the requested SNI hostname sent from an SSL client to an SSL
* server.
*
* @author Christian Kohlschütter
*/
public final class SNIHostnameCapture {
/**
* {@link SNIMatcher} that accepts and matches "any hostname".
*/
public static final SNIMatcher ACCEPT_ANY_HOSTNAME = new SNIMatcher(
StandardConstants.SNI_HOST_NAME) {
@Override
public boolean matches(SNIServerName serverName) {
return serverName.getType() == StandardConstants.SNI_HOST_NAME;
}
};
private final CompletableFuture hostnameFuture = new CompletableFuture<>();
private final Supplier defaultHostnameSupplier;
private SNIHostnameCapture(Supplier defaultHostnameSupplier) {
this.defaultHostnameSupplier = defaultHostnameSupplier;
}
/**
* Configures the given server {@link SSLSocket} to match the given hostname pattern.
*
* The matched hostname is then accessible after the handshake is completed, via
* {@link #getHostname()}. If no hostname was retrieved, {@code null} is assumed.
*
* @param sslSocket The socket to configure.
* @param hostnameMatcher The matcher to use.
* @return The {@link SNIHostnameCapture} instance.
* @see #ACCEPT_ANY_HOSTNAME
*/
public static SNIHostnameCapture configure(SSLSocket sslSocket, SNIMatcher hostnameMatcher) {
return configure(sslSocket, hostnameMatcher, null);
}
/**
* Configures the given server {@link SSLSocket} to match the given hostname pattern.
*
* The matched hostname is then accessible after the handshake is completed, via
* {@link #getHostname()}. If no hostname was retrieved, a fallback is retrieved via the given
* supplier.
*
* @param sslSocket The socket to configure.
* @param hostnameMatcher The matcher to use.
* @param defaultHostnameSupplier The supplier for a default hostname, or {@code null}.
* @return The {@link SNIHostnameCapture} instance.
* @see #ACCEPT_ANY_HOSTNAME
*/
public static SNIHostnameCapture configure(SSLSocket sslSocket, SNIMatcher hostnameMatcher,
Supplier defaultHostnameSupplier) {
SNIHostnameCapture capture = new SNIHostnameCapture(defaultHostnameSupplier == null ? () -> null
: defaultHostnameSupplier);
sslSocket.addHandshakeCompletedListener((e) -> {
capture.set(null);
});
SSLParametersUtil.setSNIMatcher(sslSocket, new CallbackSNIMatcher(hostnameMatcher, (name,
matches) -> {
if (matches && name instanceof SNIHostName) {
capture.set(((SNIHostName) name).getAsciiName());
}
}));
return capture;
}
// @ExcludeFromCodeCoverageGeneratedReport(reason = "if-statement is just a precaution")
private void set(String hostname) {
hostnameFuture.complete(hostname);
}
/**
* Checks if a hostname can be returned by calling {@link #getHostname()} (which most likely means
* the handshake is complete), optionally waiting up to the given time interval if not yet
* complete.
*
* @param timeout The maximum timeout value to wait for.
* @param unit Timeout unit.
* @return {@code true} if {@link #getHostname()} will not throw an {@link IllegalStateException}.
* @throws InterruptedException if the current thread was interrupted while waiting.
*/
public boolean isComplete(long timeout, TimeUnit unit) throws InterruptedException {
try {
hostnameFuture.get(timeout, unit);
return hostnameFuture.isDone();
} catch (ExecutionException | TimeoutException e) {
return false;
}
}
/**
* Checks if a hostname can be returned by calling {@link #getHostname()} (which most likely means
* the handshake is complete).
*
* @return {@code true} if {@link #getHostname()} will not throw an {@link IllegalStateException}.
*/
public boolean isComplete() {
return hostnameFuture.isDone();
}
/**
* Returns the hostname (either the retrieved one, or a fallback), which could also be
* {@code null}.
*
* If the method is called before the handshake is complete (check with {@link #isComplete()} or
* simply call after {@link SSLSocket#startHandshake()}), an {@link IllegalStateException} is
* thrown.
*
* @return The hostname, or {@code null}.
* @throws IllegalStateException if the method was called before a hostname could be retrieved.
*/
@SuppressFBWarnings("NP_NONNULL_PARAM_VIOLATION")
public String getHostname() {
if (!isComplete()) {
throw new IllegalStateException("Handshake not yet complete");
}
String hn = hostnameFuture.getNow(null);
if (hn == null) {
return defaultHostnameSupplier.get();
} else {
return hn;
}
}
/**
* Returns the hostname from the data stored in a socket's {@link ExtendedSSLSession}, if
* available. The default fallback handler is used if the data could not be retrieved.
*
* This is only for testing purposes. BouncyCastle doesn't support this, for example.
*
* @param socket The socket.
* @return The hostname (retrieved or fallback).
*/
String getHostnameFromSSLSession(SSLSocket socket,
Consumer usoCallback) {
SSLSession session = socket.getSession();
if (session instanceof ExtendedSSLSession) {
ExtendedSSLSession extSession = (ExtendedSSLSession) session;
try {
List list = extSession.getRequestedServerNames();
if (list != null) {
for (SNIServerName sn : list) {
if (sn instanceof SNIHostName) {
return ((SNIHostName) sn).getAsciiName();
} else if (sn.getType() == StandardConstants.SNI_HOST_NAME) {
return new SNIHostName(sn.getEncoded()).getAsciiName();
}
}
}
} catch (UnsupportedOperationException e) {
// fall through
if (usoCallback != null) {
usoCallback.accept(e);
}
}
}
return defaultHostnameSupplier.get();
}
}