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/*
* Copyright 2019 The Netty Project
*
* The Netty Project 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 io.netty.handler.ssl;
import io.netty.buffer.ByteBufUtil;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.internal.ReflectionUtil;
import io.netty.util.internal.SystemPropertyUtil;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import javax.net.ssl.SSLEngine;
import javax.net.ssl.SSLSession;
import java.lang.reflect.Field;
/**
* The {@link SslMasterKeyHandler} is a channel-handler you can include in your pipeline to consume the master key
* & session identifier for a TLS session.
* This can be very useful, for instance the {@link WiresharkSslMasterKeyHandler} implementation will
* log the secret & identifier in a format that is consumable by Wireshark -- allowing easy decryption of pcap/tcpdumps.
*/
public abstract class SslMasterKeyHandler extends ChannelInboundHandlerAdapter {
private static final InternalLogger logger = InternalLoggerFactory.getInstance(SslMasterKeyHandler.class);
/**
* The JRE SSLSessionImpl cannot be imported
*/
private static final Class SSL_SESSIONIMPL_CLASS;
/**
* The master key field in the SSLSessionImpl
*/
private static final Field SSL_SESSIONIMPL_MASTER_SECRET_FIELD;
/**
* A system property that can be used to turn on/off the {@link SslMasterKeyHandler} dynamically without having
* to edit your pipeline.
* -Dio.netty.ssl.masterKeyHandler=true
*/
public static final String SYSTEM_PROP_KEY = "io.netty.ssl.masterKeyHandler";
/**
* The unavailability cause of whether the private Sun implementation of SSLSessionImpl is available.
*/
private static final Throwable UNAVAILABILITY_CAUSE;
static {
Throwable cause = null;
Class clazz = null;
Field field = null;
try {
clazz = Class.forName("sun.security.ssl.SSLSessionImpl");
field = clazz.getDeclaredField("masterSecret");
cause = ReflectionUtil.trySetAccessible(field, true);
} catch (Throwable e) {
cause = e;
logger.debug("sun.security.ssl.SSLSessionImpl is unavailable.", e);
}
UNAVAILABILITY_CAUSE = cause;
SSL_SESSIONIMPL_CLASS = clazz;
SSL_SESSIONIMPL_MASTER_SECRET_FIELD = field;
}
/**
* Constructor.
*/
protected SslMasterKeyHandler() {
}
/**
* Ensure that SSLSessionImpl is available.
* @throws UnsatisfiedLinkError if unavailable
*/
public static void ensureSunSslEngineAvailability() {
if (UNAVAILABILITY_CAUSE != null) {
throw new IllegalStateException(
"Failed to find SSLSessionImpl on classpath", UNAVAILABILITY_CAUSE);
}
}
/**
* Returns the cause of unavailability.
*
* @return the cause if unavailable. {@code null} if available.
*/
public static Throwable sunSslEngineUnavailabilityCause() {
return UNAVAILABILITY_CAUSE;
}
/* Returns {@code true} if and only if sun.security.ssl.SSLSessionImpl exists in the runtime.
*/
public static boolean isSunSslEngineAvailable() {
return UNAVAILABILITY_CAUSE == null;
}
/**
* Consume the master key for the session and the sessionId
* @param masterKey A 48-byte secret shared between the client and server.
* @param session The current TLS session
*/
protected abstract void accept(SecretKey masterKey, SSLSession session);
@Override
public final void userEventTriggered(ChannelHandlerContext ctx, Object evt) {
//only try to log the session info if the ssl handshake has successfully completed.
if (evt == SslHandshakeCompletionEvent.SUCCESS) {
boolean shouldHandle = SystemPropertyUtil.getBoolean(SYSTEM_PROP_KEY, false);
if (shouldHandle) {
final SslHandler handler = ctx.pipeline().get(SslHandler.class);
final SSLEngine engine = handler.engine();
final SSLSession sslSession = engine.getSession();
//the OpenJDK does not expose a way to get the master secret, so try to use reflection to get it.
if (isSunSslEngineAvailable() && sslSession.getClass().equals(SSL_SESSIONIMPL_CLASS)) {
final SecretKey secretKey;
try {
secretKey = (SecretKey) SSL_SESSIONIMPL_MASTER_SECRET_FIELD.get(sslSession);
} catch (IllegalAccessException e) {
throw new IllegalArgumentException("Failed to access the field 'masterSecret' " +
"via reflection.", e);
}
accept(secretKey, sslSession);
} else if (OpenSsl.isAvailable() && engine instanceof ReferenceCountedOpenSslEngine) {
SecretKeySpec secretKey = ((ReferenceCountedOpenSslEngine) engine).masterKey();
accept(secretKey, sslSession);
}
}
}
ctx.fireUserEventTriggered(evt);
}
/**
* Create a {@link WiresharkSslMasterKeyHandler} instance.
* This TLS master key handler logs the master key and session-id in a format
* understood by Wireshark -- this can be especially useful if you need to ever
* decrypt a TLS session and are using perfect forward secrecy (i.e. Diffie-Hellman)
* The key and session identifier are forwarded to the log named 'io.netty.wireshark'.
*/
public static SslMasterKeyHandler newWireSharkSslMasterKeyHandler() {
return new WiresharkSslMasterKeyHandler();
}
/**
* Record the session identifier and master key to the {@link InternalLogger} named io.netty.wireshark.
* ex. RSA Session-ID:XXX Master-Key:YYY
* This format is understood by Wireshark 1.6.0.
* https://code.wireshark.org/review/gitweb?p=wireshark.git;a=commit;h=686d4cabb41185591c361f9ec6b709034317144b
* The key and session identifier are forwarded to the log named 'io.netty.wireshark'.
*/
private static final class WiresharkSslMasterKeyHandler extends SslMasterKeyHandler {
private static final InternalLogger wireshark_logger =
InternalLoggerFactory.getInstance("io.netty.wireshark");
private static final char[] hexCode = "0123456789ABCDEF".toCharArray();
@Override
protected void accept(SecretKey masterKey, SSLSession session) {
if (masterKey.getEncoded().length != 48) {
throw new IllegalArgumentException("An invalid length master key was provided.");
}
final byte[] sessionId = session.getId();
wireshark_logger.warn("RSA Session-ID:{} Master-Key:{}",
ByteBufUtil.hexDump(sessionId).toLowerCase(),
ByteBufUtil.hexDump(masterKey.getEncoded()).toLowerCase());
}
}
}