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org.bouncycastle.tls.DTLSRecordLayer Maven / Gradle / Ivy
package org.bouncycastle.tls;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.SocketTimeoutException;
import org.bouncycastle.tls.crypto.TlsCipher;
import org.bouncycastle.tls.crypto.TlsNullNullCipher;
import org.bouncycastle.util.Arrays;
class DTLSRecordLayer
implements DatagramTransport
{
private static final int RECORD_HEADER_LENGTH = 13;
private static final int MAX_FRAGMENT_LENGTH = 1 << 14;
private static final long TCP_MSL = 1000L * 60 * 2;
private static final long RETRANSMIT_TIMEOUT = TCP_MSL * 2;
static byte[] receiveClientHelloRecord(byte[] data, int dataOff, int dataLen) throws IOException
{
if (dataLen < RECORD_HEADER_LENGTH)
{
return null;
}
short contentType = TlsUtils.readUint8(data, dataOff + 0);
if (ContentType.handshake != contentType)
{
return null;
}
ProtocolVersion version = TlsUtils.readVersion(data, dataOff + 1);
if (!ProtocolVersion.DTLSv10.isEqualOrEarlierVersionOf(version))
{
return null;
}
int epoch = TlsUtils.readUint16(data, dataOff + 3);
if (0 != epoch)
{
return null;
}
// long sequenceNumber = TlsUtils.readUint48(data, dataOff + 5);
int length = TlsUtils.readUint16(data, dataOff + 11);
if (dataLen != RECORD_HEADER_LENGTH + length)
{
return null;
}
return Arrays.copyOfRange(data, dataOff + RECORD_HEADER_LENGTH, dataOff + dataLen);
}
static void sendHelloVerifyRequestRecord(DatagramSender sender, long recordSeq, byte[] message) throws IOException
{
TlsUtils.checkUint16(message.length);
byte[] record = new byte[RECORD_HEADER_LENGTH + message.length];
TlsUtils.writeUint8(ContentType.handshake, record, 0);
TlsUtils.writeVersion(ProtocolVersion.DTLSv10, record, 1);
TlsUtils.writeUint16(0, record, 3);
TlsUtils.writeUint48(recordSeq, record, 5);
TlsUtils.writeUint16(message.length, record, 11);
System.arraycopy(message, 0, record, RECORD_HEADER_LENGTH, message.length);
sendDatagram(sender, record);
}
private static void sendDatagram(DatagramSender sender, byte[] record)
throws IOException
{
try
{
sender.send(record, 0, record.length);
}
catch (InterruptedIOException e)
{
e.bytesTransferred = 0;
throw e;
}
}
private final TlsContext context;
private final TlsPeer peer;
private final DatagramTransport transport;
private final ByteQueue recordQueue = new ByteQueue();
private volatile boolean closed = false;
private volatile boolean failed = false;
// TODO[dtls13] Review the draft/RFC (legacy_record_version) to see if readVersion can be removed
private volatile ProtocolVersion readVersion = null, writeVersion = null;
private volatile boolean inConnection;
private volatile boolean inHandshake;
private volatile int plaintextLimit;
private DTLSEpoch currentEpoch, pendingEpoch;
private DTLSEpoch readEpoch, writeEpoch;
private DTLSHandshakeRetransmit retransmit = null;
private DTLSEpoch retransmitEpoch = null;
private Timeout retransmitTimeout = null;
private TlsHeartbeat heartbeat = null; // If non-null, controls the sending of heartbeat requests
private boolean heartBeatResponder = false; // Whether we should send heartbeat responses
private HeartbeatMessage heartbeatInFlight = null; // The current in-flight heartbeat request, if any
private Timeout heartbeatTimeout = null; // Idle timeout (if none in-flight), else expiry timeout for response
private int heartbeatResendMillis = -1; // Delay before retransmit of current in-flight heartbeat request
private Timeout heartbeatResendTimeout = null; // Timeout for next retransmit of the in-flight heartbeat request
DTLSRecordLayer(TlsContext context, TlsPeer peer, DatagramTransport transport)
{
this.context = context;
this.peer = peer;
this.transport = transport;
this.inHandshake = true;
this.currentEpoch = new DTLSEpoch(0, new TlsNullNullCipher());
this.pendingEpoch = null;
this.readEpoch = currentEpoch;
this.writeEpoch = currentEpoch;
setPlaintextLimit(MAX_FRAGMENT_LENGTH);
}
void resetAfterHelloVerifyRequestClient()
{
currentEpoch.getReplayWindow().reset();
}
void resetAfterHelloVerifyRequestServer(long writeRecordSeqNo)
{
this.inConnection = true;
currentEpoch.setSequenceNumber(writeRecordSeqNo);
/*
* TODO The sequence number reflects one that the client has already sent, so we could
* initialize the replay window here accordingly.
*/
}
void setPlaintextLimit(int plaintextLimit)
{
this.plaintextLimit = plaintextLimit;
}
int getReadEpoch()
{
return readEpoch.getEpoch();
}
ProtocolVersion getReadVersion()
{
return readVersion;
}
void setReadVersion(ProtocolVersion readVersion)
{
this.readVersion = readVersion;
}
void setWriteVersion(ProtocolVersion writeVersion)
{
this.writeVersion = writeVersion;
}
void initPendingEpoch(TlsCipher pendingCipher)
{
if (pendingEpoch != null)
{
throw new IllegalStateException();
}
/*
* TODO "In order to ensure that any given sequence/epoch pair is unique, implementations
* MUST NOT allow the same epoch value to be reused within two times the TCP maximum segment
* lifetime."
*/
// TODO Check for overflow
this.pendingEpoch = new DTLSEpoch(writeEpoch.getEpoch() + 1, pendingCipher);
}
void handshakeSuccessful(DTLSHandshakeRetransmit retransmit)
{
if (readEpoch == currentEpoch || writeEpoch == currentEpoch)
{
// TODO
throw new IllegalStateException();
}
if (null != retransmit)
{
this.retransmit = retransmit;
this.retransmitEpoch = currentEpoch;
this.retransmitTimeout = new Timeout(RETRANSMIT_TIMEOUT);
}
this.inHandshake = false;
this.currentEpoch = pendingEpoch;
this.pendingEpoch = null;
}
void initHeartbeat(TlsHeartbeat heartbeat, boolean heartbeatResponder)
{
if (inHandshake)
{
throw new IllegalStateException();
}
this.heartbeat = heartbeat;
this.heartBeatResponder = heartbeatResponder;
if (null != heartbeat)
{
resetHeartbeat();
}
}
void resetWriteEpoch()
{
if (null != retransmitEpoch)
{
this.writeEpoch = retransmitEpoch;
}
else
{
this.writeEpoch = currentEpoch;
}
}
public int getReceiveLimit()
throws IOException
{
return Math.min(this.plaintextLimit,
readEpoch.getCipher().getPlaintextLimit(transport.getReceiveLimit() - RECORD_HEADER_LENGTH));
}
public int getSendLimit()
throws IOException
{
return Math.min(this.plaintextLimit,
writeEpoch.getCipher().getPlaintextLimit(transport.getSendLimit() - RECORD_HEADER_LENGTH));
}
public int receive(byte[] buf, int off, int len, int waitMillis)
throws IOException
{
long currentTimeMillis = System.currentTimeMillis();
Timeout timeout = Timeout.forWaitMillis(waitMillis, currentTimeMillis);
byte[] record = null;
while (waitMillis >= 0)
{
if (null != retransmitTimeout && retransmitTimeout.remainingMillis(currentTimeMillis) < 1)
{
retransmit = null;
retransmitEpoch = null;
retransmitTimeout = null;
}
if (Timeout.hasExpired(heartbeatTimeout, currentTimeMillis))
{
if (null != heartbeatInFlight)
{
throw new TlsTimeoutException("Heartbeat timed out");
}
this.heartbeatInFlight = HeartbeatMessage.create(context, HeartbeatMessageType.heartbeat_request,
heartbeat.generatePayload());
this.heartbeatTimeout = new Timeout(heartbeat.getTimeoutMillis(), currentTimeMillis);
this.heartbeatResendMillis = DTLSReliableHandshake.INITIAL_RESEND_MILLIS;
this.heartbeatResendTimeout = new Timeout(heartbeatResendMillis, currentTimeMillis);
sendHeartbeatMessage(heartbeatInFlight);
}
else if (Timeout.hasExpired(heartbeatResendTimeout, currentTimeMillis))
{
this.heartbeatResendMillis = DTLSReliableHandshake.backOff(heartbeatResendMillis);
this.heartbeatResendTimeout = new Timeout(heartbeatResendMillis, currentTimeMillis);
sendHeartbeatMessage(heartbeatInFlight);
}
waitMillis = Timeout.constrainWaitMillis(waitMillis, heartbeatTimeout, currentTimeMillis);
waitMillis = Timeout.constrainWaitMillis(waitMillis, heartbeatResendTimeout, currentTimeMillis);
// NOTE: Guard against bad logic giving a negative value
if (waitMillis < 0)
{
waitMillis = 1;
}
int receiveLimit = Math.min(len, getReceiveLimit()) + RECORD_HEADER_LENGTH;
if (null == record || record.length < receiveLimit)
{
record = new byte[receiveLimit];
}
int received = receiveRecord(record, 0, receiveLimit, waitMillis);
int processed = processRecord(received, record, buf, off);
if (processed >= 0)
{
return processed;
}
currentTimeMillis = System.currentTimeMillis();
waitMillis = Timeout.getWaitMillis(timeout, currentTimeMillis);
}
return -1;
}
public void send(byte[] buf, int off, int len)
throws IOException
{
short contentType = ContentType.application_data;
if (this.inHandshake || this.writeEpoch == this.retransmitEpoch)
{
contentType = ContentType.handshake;
short handshakeType = TlsUtils.readUint8(buf, off);
if (handshakeType == HandshakeType.finished)
{
DTLSEpoch nextEpoch = null;
if (this.inHandshake)
{
nextEpoch = pendingEpoch;
}
else if (this.writeEpoch == this.retransmitEpoch)
{
nextEpoch = currentEpoch;
}
if (nextEpoch == null)
{
// TODO
throw new IllegalStateException();
}
// Implicitly send change_cipher_spec and change to pending cipher state
// TODO Send change_cipher_spec and finished records in single datagram?
byte[] data = new byte[]{ 1 };
sendRecord(ContentType.change_cipher_spec, data, 0, data.length);
writeEpoch = nextEpoch;
}
}
sendRecord(contentType, buf, off, len);
}
public void close()
throws IOException
{
if (!closed)
{
if (inHandshake && inConnection)
{
warn(AlertDescription.user_canceled, "User canceled handshake");
}
closeTransport();
}
}
void fail(short alertDescription)
{
if (!closed)
{
if (inConnection)
{
try
{
raiseAlert(AlertLevel.fatal, alertDescription, null, null);
}
catch (Exception e)
{
// Ignore
}
}
failed = true;
closeTransport();
}
}
void failed()
{
if (!closed)
{
failed = true;
closeTransport();
}
}
void warn(short alertDescription, String message)
throws IOException
{
raiseAlert(AlertLevel.warning, alertDescription, message, null);
}
private void closeTransport()
{
if (!closed)
{
/*
* RFC 5246 7.2.1. Unless some other fatal alert has been transmitted, each party is
* required to send a close_notify alert before closing the write side of the
* connection. The other party MUST respond with a close_notify alert of its own and
* close down the connection immediately, discarding any pending writes.
*/
try
{
if (!failed)
{
warn(AlertDescription.close_notify, null);
}
transport.close();
}
catch (Exception e)
{
// Ignore
}
closed = true;
}
}
private void raiseAlert(short alertLevel, short alertDescription, String message, Throwable cause)
throws IOException
{
peer.notifyAlertRaised(alertLevel, alertDescription, message, cause);
byte[] error = new byte[2];
error[0] = (byte)alertLevel;
error[1] = (byte)alertDescription;
sendRecord(ContentType.alert, error, 0, 2);
}
private int receiveDatagram(byte[] buf, int off, int len, int waitMillis)
throws IOException
{
try
{
return transport.receive(buf, off, len, waitMillis);
}
catch (SocketTimeoutException e)
{
return -1;
}
catch (InterruptedIOException e)
{
e.bytesTransferred = 0;
throw e;
}
}
// TODO Include 'currentTimeMillis' as an argument, use with Timeout, resetHeartbeat
private int processRecord(int received, byte[] record, byte[] buf, int off)
throws IOException
{
// NOTE: received < 0 (timeout) is covered by this first case
if (received < RECORD_HEADER_LENGTH)
{
return -1;
}
int length = TlsUtils.readUint16(record, 11);
if (received != (length + RECORD_HEADER_LENGTH))
{
return -1;
}
short type = TlsUtils.readUint8(record, 0);
switch (type)
{
case ContentType.alert:
case ContentType.application_data:
case ContentType.change_cipher_spec:
case ContentType.handshake:
case ContentType.heartbeat:
break;
default:
return -1;
}
int epoch = TlsUtils.readUint16(record, 3);
DTLSEpoch recordEpoch = null;
if (epoch == readEpoch.getEpoch())
{
recordEpoch = readEpoch;
}
else if (type == ContentType.handshake && null != retransmitEpoch
&& epoch == retransmitEpoch.getEpoch())
{
recordEpoch = retransmitEpoch;
}
if (null == recordEpoch)
{
return -1;
}
long seq = TlsUtils.readUint48(record, 5);
if (recordEpoch.getReplayWindow().shouldDiscard(seq))
{
return -1;
}
ProtocolVersion version = TlsUtils.readVersion(record, 1);
if (!version.isDTLS())
{
return -1;
}
if (null != readVersion && !readVersion.equals(version))
{
/*
* Special-case handling for retransmitted ClientHello records.
*
* TODO Revisit how 'readVersion' works, since this is quite awkward.
*/
boolean isClientHelloFragment =
getReadEpoch() == 0
&& length > 0
&& ContentType.handshake == type
&& HandshakeType.client_hello == TlsUtils.readUint8(record, RECORD_HEADER_LENGTH);
if (!isClientHelloFragment)
{
return -1;
}
}
long macSeqNo = getMacSequenceNumber(recordEpoch.getEpoch(), seq);
byte[] plaintext = recordEpoch.getCipher().decodeCiphertext(macSeqNo, type, record,
RECORD_HEADER_LENGTH, length);
recordEpoch.getReplayWindow().reportAuthenticated(seq);
if (plaintext.length > this.plaintextLimit)
{
return -1;
}
if (null == readVersion)
{
readVersion = version;
}
switch (type)
{
case ContentType.alert:
{
if (plaintext.length == 2)
{
short alertLevel = plaintext[0];
short alertDescription = plaintext[1];
peer.notifyAlertReceived(alertLevel, alertDescription);
if (alertLevel == AlertLevel.fatal)
{
failed();
throw new TlsFatalAlert(alertDescription);
}
// TODO Can close_notify be a fatal alert?
if (alertDescription == AlertDescription.close_notify)
{
closeTransport();
}
}
return -1;
}
case ContentType.application_data:
{
if (inHandshake)
{
// TODO Consider buffering application data for new epoch that arrives
// out-of-order with the Finished message
return -1;
}
break;
}
case ContentType.change_cipher_spec:
{
// Implicitly receive change_cipher_spec and change to pending cipher state
for (int i = 0; i < plaintext.length; ++i)
{
short message = TlsUtils.readUint8(plaintext, i);
if (message != ChangeCipherSpec.change_cipher_spec)
{
continue;
}
if (pendingEpoch != null)
{
readEpoch = pendingEpoch;
}
}
return -1;
}
case ContentType.handshake:
{
if (!inHandshake)
{
if (null != retransmit)
{
retransmit.receivedHandshakeRecord(epoch, plaintext, 0, plaintext.length);
}
// TODO Consider support for HelloRequest
return -1;
}
break;
}
case ContentType.heartbeat:
{
if (null != heartbeatInFlight || heartBeatResponder)
{
try
{
ByteArrayInputStream input = new ByteArrayInputStream(plaintext);
HeartbeatMessage heartbeatMessage = HeartbeatMessage.parse(input);
if (null != heartbeatMessage)
{
switch (heartbeatMessage.getType())
{
case HeartbeatMessageType.heartbeat_request:
{
if (heartBeatResponder)
{
HeartbeatMessage response = HeartbeatMessage.create(context,
HeartbeatMessageType.heartbeat_response, heartbeatMessage.getPayload());
sendHeartbeatMessage(response);
}
break;
}
case HeartbeatMessageType.heartbeat_response:
{
if (null != heartbeatInFlight
&& Arrays.areEqual(heartbeatMessage.getPayload(), heartbeatInFlight.getPayload()))
{
resetHeartbeat();
}
break;
}
default:
break;
}
}
}
catch (Exception e)
{
// Ignore
}
}
return -1;
}
}
/*
* NOTE: If we receive any non-handshake data in the new epoch implies the peer has
* received our final flight.
*/
if (!inHandshake && null != retransmit)
{
this.retransmit = null;
this.retransmitEpoch = null;
this.retransmitTimeout = null;
}
System.arraycopy(plaintext, 0, buf, off, plaintext.length);
return plaintext.length;
}
private int receiveRecord(byte[] buf, int off, int len, int waitMillis)
throws IOException
{
if (recordQueue.available() > 0)
{
int length = 0;
if (recordQueue.available() >= RECORD_HEADER_LENGTH)
{
byte[] lengthBytes = new byte[2];
recordQueue.read(lengthBytes, 0, 2, 11);
length = TlsUtils.readUint16(lengthBytes, 0);
}
int received = Math.min(recordQueue.available(), RECORD_HEADER_LENGTH + length);
recordQueue.removeData(buf, off, received, 0);
return received;
}
int received = receiveDatagram(buf, off, len, waitMillis);
if (received >= RECORD_HEADER_LENGTH)
{
this.inConnection = true;
int fragmentLength = TlsUtils.readUint16(buf, off + 11);
int recordLength = RECORD_HEADER_LENGTH + fragmentLength;
if (received > recordLength)
{
recordQueue.addData(buf, off + recordLength, received - recordLength);
received = recordLength;
}
}
return received;
}
private void resetHeartbeat()
{
this.heartbeatInFlight = null;
this.heartbeatResendMillis = -1;
this.heartbeatResendTimeout = null;
this.heartbeatTimeout = new Timeout(heartbeat.getIdleMillis());
}
private void sendHeartbeatMessage(HeartbeatMessage heartbeatMessage)
throws IOException
{
ByteArrayOutputStream output = new ByteArrayOutputStream();
heartbeatMessage.encode(output);
byte[] buf = output.toByteArray();
sendRecord(ContentType.heartbeat, buf, 0, buf.length);
}
/*
* Currently synchronized here to ensure heartbeat sends and application data sends don't
* interfere with each other. It may be overly cautious; the sequence number allocation is
* atomic, and if we synchronize only on the datagram send instead, then the only effect should
* be possible reordering of records (which might surprise a reliable transport implementation).
*/
private synchronized void sendRecord(short contentType, byte[] buf, int off, int len)
throws IOException
{
// Never send anything until a valid ClientHello has been received
if (writeVersion == null)
{
return;
}
if (len > this.plaintextLimit)
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
/*
* RFC 5246 6.2.1 Implementations MUST NOT send zero-length fragments of Handshake, Alert,
* or ChangeCipherSpec content types.
*/
if (len < 1 && contentType != ContentType.application_data)
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
int recordEpoch = writeEpoch.getEpoch();
long recordSequenceNumber = writeEpoch.allocateSequenceNumber();
byte[] ciphertext = writeEpoch.getCipher().encodePlaintext(
getMacSequenceNumber(recordEpoch, recordSequenceNumber), contentType, buf, off, len);
// TODO Check the ciphertext length?
byte[] record = new byte[ciphertext.length + RECORD_HEADER_LENGTH];
TlsUtils.writeUint8(contentType, record, 0);
TlsUtils.writeVersion(writeVersion, record, 1);
TlsUtils.writeUint16(recordEpoch, record, 3);
TlsUtils.writeUint48(recordSequenceNumber, record, 5);
TlsUtils.writeUint16(ciphertext.length, record, 11);
System.arraycopy(ciphertext, 0, record, RECORD_HEADER_LENGTH, ciphertext.length);
sendDatagram(transport, record);
}
private static long getMacSequenceNumber(int epoch, long sequence_number)
{
return ((epoch & 0xFFFFFFFFL) << 48) | sequence_number;
}
}
