org.jgroups.protocols.DH_KEY_EXCHANGE Maven / Gradle / Ivy
Go to download
This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
package org.jgroups.protocols;
import org.jgroups.*;
import org.jgroups.annotations.MBean;
import org.jgroups.annotations.Property;
import org.jgroups.conf.AttributeType;
import org.jgroups.util.MessageBatch;
import org.jgroups.util.Tuple;
import org.jgroups.util.Util;
import javax.crypto.Cipher;
import javax.crypto.KeyAgreement;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.security.*;
import java.security.spec.X509EncodedKeySpec;
import java.util.Iterator;
import java.util.function.Supplier;
/**
* Key exchange based on Diffie-Hellman-Merkle (https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange).
* Diffie-Hellman is used between a member and a key server (the coordinator) to obtain a session key
* (only known to the key server and the joiner) which is used by the key server to encrypt the shared secret symmetric
* (group) key and by the requester to decrypt the group key it gets in the response of the key server.
*
* Note that this implementation is not immune against man-in-the-middle attacks.
* @author Bela Ban
* @since 4.0.5
*/
@MBean(description="Key exchange protocol to fetch a shared secret group key from the key server." +
"That shared (symmetric) key is subsequently used to encrypt communication between cluster members")
public class DH_KEY_EXCHANGE extends KeyExchange {
protected enum Type {
// sent from joiner to key server, carries dh_key
SECRET_KEY_REQ,
// sent from key server to joiner, carries dh_key of key server, encrypted secret key and version of secret key
SECRET_KEY_RSP
}
@Property(description="The type of secret key to be sent up the stack (converted from DH). " +
"Should be the same as the algorithm part of ASYM_ENCRYPT.sym_algorithm if ASYM_ENCRYPT is used")
protected String secret_key_algorithm="AES";
@Property(description="The length of the secret key (in bits) to be sent up the stack. AES requires 128 bits. " +
"Should be the same as ASYM_ENCRYPT.sym_keylength if ASYM_ENCRYPT is used.")
protected int secret_key_length=128; // used for AES
@Property(description="Max time (in ms) that a FETCH_SECRET_KEY down event will be ignored (if an existing " +
"request is in progress) until a new request for the secret key is sent to the keyserver",type=AttributeType.TIME)
protected long timeout=2000;
/** Diffie-Hellman protocol engine */
protected KeyAgreement key_agreement;
/** The public key used for the Diffie-Hellman key exchange to obtain the session key (used to encrypt the
* keyserver's secret key) */
protected PublicKey dh_key;
/** Time (ms) when the last key request was sent, prevents too many requests */
protected long last_key_request;
protected static final KeyPairGenerator key_pair_gen;
protected static final KeyFactory dh_key_factory;
static {
try {
key_pair_gen=KeyPairGenerator.getInstance("DH");
dh_key_factory=KeyFactory.getInstance("DH");
}
catch(NoSuchAlgorithmException e) {
throw new RuntimeException(e);
}
}
public void init() throws Exception {
super.init();
if(secret_key_length % 8 != 0)
throw new IllegalStateException(String.format("secret_key_length (%d) must be a multiple of 8", secret_key_length));
ASYM_ENCRYPT asym_encrypt=findProtocolAbove(ASYM_ENCRYPT.class);
if(asym_encrypt != null) {
String sym_alg=asym_encrypt.symKeyAlgorithm();
int sym_keylen=asym_encrypt.symKeylength();
if(!Util.match(sym_alg, secret_key_algorithm)) {
log.warn("overriding %s=%s to %s from %s", "secret_key_algorithm", secret_key_algorithm,
sym_alg, ASYM_ENCRYPT.class.getSimpleName());
secret_key_algorithm=sym_alg;
}
if(sym_keylen != secret_key_length) {
log.warn("overriding %s=%d to %d from %s", "secret_key_length", secret_key_length,
sym_keylen, ASYM_ENCRYPT.class.getSimpleName());
secret_key_length=sym_keylen;
}
}
key_agreement=KeyAgreement.getInstance("DH");
}
public void fetchSecretKeyFrom(Address target) throws NoSuchAlgorithmException, InvalidKeyException {
byte[] encoded_dh_key=null;
synchronized(this) {
if(dh_key != null) {
long curr_time;
if((curr_time=System.currentTimeMillis()) - last_key_request >= timeout) {
last_key_request=curr_time;
encoded_dh_key=dh_key.getEncoded();
}
}
else {
KeyPair kp=key_pair_gen.generateKeyPair();
PrivateKey private_key=kp.getPrivate();
dh_key=kp.getPublic(); // to be sent to target
encoded_dh_key=dh_key.getEncoded();
key_agreement.init(private_key);
log.debug("%s: sending public key %s.. to %s", local_addr, print16(dh_key), target);
}
}
if(encoded_dh_key != null) {
Message msg=new EmptyMessage(target).putHeader(id, DhHeader.createSecretKeyRequest(encoded_dh_key));
down_prot.down(msg);
}
}
public Address getServerLocation() {return null;}
public Object up(Message msg) {
DhHeader hdr=msg.getHeader(id);
if(hdr != null) {
handle(hdr, msg.getSrc());
return null;
}
return up_prot.up(msg);
}
public void up(MessageBatch batch) {
Iterator it=batch.iterator();
while(it.hasNext()) {
Message msg=it.next();
DhHeader hdr=msg.getHeader(id);
if(hdr != null) {
it.remove();
handle(hdr, msg.getSrc());
}
}
if(!batch.isEmpty())
up_prot.up(batch);
}
protected void handle(DhHeader hdr, Address sender) {
try {
PublicKey pub_key=dh_key_factory.generatePublic(new X509EncodedKeySpec(hdr.dh_key));
switch(hdr.type) {
case SECRET_KEY_REQ:
handleSecretKeyRequest(pub_key, sender);
break;
case SECRET_KEY_RSP:
handleSecretKeyResponse(pub_key, hdr.encrypted_secret_key, hdr.secret_key_version, sender);
break;
default:
log.warn("unknown header type %d", hdr.type);
}
}
catch(Throwable t) {
log.error(String.format("failed handling request %s", hdr), t);
}
}
protected void handleSecretKeyRequest(PublicKey dh_public_key, Address sender) throws Exception {
KeyPair kp=key_pair_gen.generateKeyPair();
PrivateKey private_key=kp.getPrivate();
PublicKey public_key_rsp=kp.getPublic(); // sent back as part of the response
byte[] version;
byte[] encrypted_secret_key;
log.debug("%s: received public key %s.. from %s", local_addr, print16(dh_public_key), sender);
synchronized(this) {
key_agreement.init(private_key);
key_agreement.doPhase(dh_public_key, true);
// Diffie-Hellman secret session key, to encrypt secret key
byte[] secret_session_key=key_agreement.generateSecret();
SecretKey hashed_session_key=hash(secret_session_key);
Cipher encrypter=Cipher.getInstance(secret_key_algorithm);
encrypter.init(Cipher.ENCRYPT_MODE, hashed_session_key);
Tuple tuple=(Tuple)up_prot.up(new Event(Event.GET_SECRET_KEY));
SecretKey secret_key=tuple.getVal1();
version=tuple.getVal2();
encrypted_secret_key=encrypter.doFinal(secret_key.getEncoded());
}
log.debug("%s: sending public key rsp %s.. to %s", local_addr, print16(public_key_rsp), sender);
// send response to sender with public_key_rsp, encrypted secret key and secret key version
Message rsp=new EmptyMessage(sender)
.putHeader(id, DhHeader.createSecretKeyResponse(public_key_rsp.getEncoded(),
encrypted_secret_key, version));
down_prot.down(rsp);
}
protected void handleSecretKeyResponse(PublicKey dh_public_key, byte[] encrypted_secret_key,
byte[] version, Address sender) throws Exception {
Tuple tuple=null;
log.debug("%s: received public key rsp %s.. from %s", local_addr, print16(dh_public_key), sender);
synchronized(this) {
key_agreement.doPhase(dh_public_key, true);
// Diffie-Hellman secret session key, to decrypt secret key
byte[] secret_session_key=key_agreement.generateSecret();
SecretKey hashed_session_key=hash(secret_session_key);
Cipher encrypter=Cipher.getInstance(secret_key_algorithm);
encrypter.init(Cipher.DECRYPT_MODE, hashed_session_key);
byte[] secret_key=encrypter.doFinal(encrypted_secret_key); // <-- this is the shared group key
SecretKey sk=new SecretKeySpec(secret_key, secret_key_algorithm);
tuple=new Tuple<>(sk, version);
dh_key=null;
}
log.debug("%s: sending up secret key (version: %s)", local_addr, Util.byteArrayToHexString(version));
up_prot.up(new Event(Event.SET_SECRET_KEY, tuple));
}
protected SecretKey hash(byte[] key) throws Exception {
// use SHA256 to create a hash of secret_key and only then truncate it to secret_key_length
MessageDigest digest=MessageDigest.getInstance("SHA-256");
digest.update(key);
byte[] hashed_key=digest.digest();
return new SecretKeySpec(hashed_key, 0, secret_key_length/8, secret_key_algorithm);
}
protected static String print16(PublicKey pub_key) {
// use SHA256 to create a hash of secret_key and only then truncate it to secret_key_length
MessageDigest digest=null;
try {
digest=MessageDigest.getInstance("SHA-256");
digest.update(pub_key.getEncoded());
return Util.byteArrayToHexString(digest.digest(), 0, 16);
}
catch(NoSuchAlgorithmException e) {
return e.toString();
}
}
public static class DhHeader extends Header {
protected Type type;
protected byte[] dh_key;
protected byte[] encrypted_secret_key;
protected byte[] secret_key_version;
public DhHeader() {
}
public static DhHeader createSecretKeyRequest(byte[] dh_key) {
DhHeader hdr=new DhHeader();
hdr.type=Type.SECRET_KEY_REQ;
hdr.dh_key=dh_key;
return hdr;
}
public static DhHeader createSecretKeyResponse(byte[] dh_pub_key, byte[] encrypted_secret_key,
byte[] version) {
DhHeader hdr=new DhHeader();
hdr.type=Type.SECRET_KEY_RSP;
hdr.dh_key=dh_pub_key;
hdr.encrypted_secret_key=encrypted_secret_key;
hdr.secret_key_version=version;
return hdr;
}
public Supplier create() {return DhHeader::new;}
public short getMagicId() {return 92;}
public byte[] dhKey() {return dh_key;}
public byte[] encryptedSecret() {return encrypted_secret_key;}
public byte[] version() {return secret_key_version;}
@Override
public int serializedSize() {
switch(type) {
case SECRET_KEY_REQ:
return Global.BYTE_SIZE + Global.INT_SIZE
+ (dh_key != null? dh_key.length : 0);
case SECRET_KEY_RSP:
return Global.BYTE_SIZE + Global.INT_SIZE*3
+ (dh_key != null? dh_key.length : 0)
+ (encrypted_secret_key != null? encrypted_secret_key.length : 0)
+ (secret_key_version != null? secret_key_version.length : 0);
default: return 0; // should never happen!
}
}
@Override
public void writeTo(DataOutput out) throws IOException {
out.writeByte(type.ordinal());
switch(type) {
case SECRET_KEY_REQ:
int size=dh_key != null? dh_key.length : 0;
out.writeInt(size);
if(dh_key != null)
out.write(dh_key);
break;
case SECRET_KEY_RSP:
size=dh_key != null? dh_key.length : 0;
out.writeInt(size);
if(size > 0)
out.write(dh_key);
size=encrypted_secret_key != null? encrypted_secret_key.length : 0;
out.writeInt(size);
if(encrypted_secret_key != null)
out.write(encrypted_secret_key);
size=secret_key_version != null? secret_key_version.length : 0;
out.writeInt(size);
if(secret_key_version != null)
out.write(secret_key_version);
break;
}
}
@Override
public void readFrom(DataInput in) throws IOException {
byte ordinal=in.readByte();
type=Type.values()[ordinal];
int size=in.readInt();
if(size > 0) {
dh_key=new byte[size];
in.readFully(dh_key);
}
switch(type) {
case SECRET_KEY_REQ:
break;
case SECRET_KEY_RSP:
size=in.readInt();
if(size > 0) {
encrypted_secret_key=new byte[size];
in.readFully(encrypted_secret_key);
}
size=in.readInt();
if(size > 0) {
secret_key_version=new byte[size];
in.readFully(secret_key_version);
}
break;
}
}
public String toString() {
if(type == null) return "n/a";
switch(type) {
case SECRET_KEY_REQ:
return String.format("%s dh-key %d bytes", type, dh_key.length);
case SECRET_KEY_RSP:
return String.format("%s dh-key %d bytes, encrypted secret %d bytes, version: %s", type, dh_key.length,
encrypted_secret_key.length, Util.byteArrayToHexString(secret_key_version));
default: return "n/a";
}
}
}
}