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net.luminis.tls.handshake.ClientHello Maven / Gradle / Ivy
/*
* Copyright © 2019, 2020, 2021, 2022, 2023, 2024 Peter Doornbosch
*
* This file is part of Agent15, an implementation of TLS 1.3 in Java.
*
* Agent15 is free software: you can redistribute it and/or modify it under
* the terms of the GNU Lesser General Public License as published by the
* Free Software Foundation, either version 3 of the License, or (at your option)
* any later version.
*
* Agent15 is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
* more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see SUPPORTED_CIPHERS = List.of(TlsConstants.CipherSuite.TLS_AES_128_GCM_SHA256);
private static final int MINIMAL_MESSAGE_LENGTH = 1 + 3 + 2 + 32 + 1 + 2 + 2 + 2 + 2;
private static final List SUPPORTED_SIGNATURES = List.of(TlsConstants.SignatureScheme.rsa_pss_rsae_sha256);
private static Random random = new Random();
private static SecureRandom secureRandom = new SecureRandom();
private final byte[] data;
private final int pskExtensionStartPosition;
private byte[] clientRandom;
private List cipherSuites = new ArrayList<>();
private List extensions;
/**
* Parses a ClientHello message from a byte stream.
* @param buffer
* @throws TlsProtocolException
* @throws IllegalParameterAlert
*/
public ClientHello(ByteBuffer buffer, ExtensionParser customExtensionParser) throws TlsProtocolException, IllegalParameterAlert {
int startPosition = buffer.position();
if (buffer.remaining() < 4) {
throw new DecodeErrorException("message underflow");
}
if (buffer.remaining() < MINIMAL_MESSAGE_LENGTH) {
throw new DecodeErrorException("message underflow");
}
int messageType = buffer.get();
if (messageType != TlsConstants.HandshakeType.client_hello.value) {
throw new RuntimeException(); // Programming error
}
int length = ((buffer.get() & 0xff) << 16) | ((buffer.get() & 0xff) << 8) | (buffer.get() & 0xff);
if (buffer.remaining() < length) {
throw new DecodeErrorException("message underflow");
}
int legacyVersion = buffer.getShort();
if (legacyVersion != 0x0303) {
throw new DecodeErrorException("legacy version must be 0303");
}
clientRandom = new byte[32];
buffer.get(clientRandom);
int sessionIdLength = buffer.get();
if (sessionIdLength > 0) {
buffer.get(new byte[sessionIdLength]);
}
int cipherSuitesLength = buffer.getShort();
for (int i = 0; i < cipherSuitesLength; i += 2) {
int cipherSuiteValue = buffer.getShort();
Arrays.stream(TlsConstants.CipherSuite.values())
.filter(item -> item.value == cipherSuiteValue)
.findFirst()
// https://tools.ietf.org/html/rfc8446#section-4.1.2
// "If the list contains cipher suites that the server does not recognize, support, or wish to use,
// the server MUST ignore those cipher suites and process the remaining ones as usual."
.ifPresent(item -> cipherSuites.add(item));
}
// https://datatracker.ietf.org/doc/html/rfc8446#section-4.1.2
// "For every TLS 1.3 ClientHello, this vector MUST contain exactly one byte, set to zero, which corresponds to
// the "null" compression method in prior versions of TLS. If a TLS 1.3 ClientHello is received with any other
// value in this field, the server MUST abort the handshake with an "illegal_parameter" alert."
int legacyCompressionMethodsLength = buffer.get();
int legacyCompressionMethod = buffer.get();
if (legacyCompressionMethodsLength != 1 || legacyCompressionMethod != 0) {
throw new IllegalParameterAlert("Invalid legacy compression method");
}
int extensionStart = buffer.position();
extensions = parseExtensions(buffer, TlsConstants.HandshakeType.client_hello, customExtensionParser);
if (extensions.stream().anyMatch(ext -> ext instanceof PreSharedKeyExtension)) {
buffer.position(extensionStart);
pskExtensionStartPosition = findPositionLastExtension(buffer);
// https://datatracker.ietf.org/doc/html/rfc8446#section-4.2.11
// "The "pre_shared_key" extension MUST be the last extension in the ClientHello (...). Servers MUST check
// that it is the last extension and otherwise fail the handshake with an "illegal_parameter" alert."
if (! (extensions.get(extensions.size() - 1) instanceof PreSharedKeyExtension)) {
throw new IllegalParameterAlert("pre_shared_key extension MUST be the last extension in the ClientHello");
}
}
else {
pskExtensionStartPosition = -1;
}
data = new byte[buffer.position() - startPosition];
buffer.position(startPosition);
buffer.get(data);
}
public ClientHello(String serverName, ECPublicKey publicKey) {
this(serverName, publicKey, true, SUPPORTED_CIPHERS, SUPPORTED_SIGNATURES, secp256r1, Collections.emptyList(), null, PskKeyEstablishmentMode.both);
}
public ClientHello(String serverName, ECPublicKey publicKey, boolean compatibilityMode, List extraExtensions) {
this(serverName, publicKey, compatibilityMode, SUPPORTED_CIPHERS, SUPPORTED_SIGNATURES, secp256r1, extraExtensions, null, PskKeyEstablishmentMode.both);
}
/**
* @param serverName
* @param publicKey
* @param compatibilityMode
* @param supportedCiphers
* @param supportedSignatures
* @param ecCurve
* @param extraExtensions
* @param binderCalculator can be null when no ClientHelloPreSharedKeyExtension is present, must be non-null when ClientHelloPreSharedKeyExtension is present.
* @param pskKeyEstablishmentMode
*/
public ClientHello(String serverName, PublicKey publicKey, boolean compatibilityMode, List supportedCiphers,
List supportedSignatures, TlsConstants.NamedGroup ecCurve,
List extraExtensions, BinderCalculator binderCalculator, PskKeyEstablishmentMode pskKeyEstablishmentMode) {
this.cipherSuites = supportedCiphers;
ByteBuffer buffer = ByteBuffer.allocate(MAX_CLIENT_HELLO_SIZE);
// HandshakeType client_hello(1),
buffer.put((byte) 1);
// Reserve 3 bytes for length
byte[] length = new byte[3];
buffer.put(length);
// client version
buffer.put((byte) 0x03);
buffer.put((byte) 0x03);
// client random 32 bytes
clientRandom = new byte[32];
secureRandom.nextBytes(clientRandom);
buffer.put(clientRandom);
byte[] sessionId;
if (compatibilityMode) {
sessionId = new byte[32];
random.nextBytes(sessionId);
}
else {
sessionId = new byte[0];
}
buffer.put((byte) sessionId.length);
if (sessionId.length > 0)
buffer.put(sessionId);
buffer.putShort((short) (supportedCiphers.size() * 2));
for (TlsConstants.CipherSuite cipher: supportedCiphers) {
buffer.putShort(cipher.value);
}
// Compression
// "For every TLS 1.3 ClientHello, this vector MUST contain exactly one byte, set to zero, which corresponds to
// the "null" compression method in prior versions of TLS. "
buffer.put(new byte[] {
(byte) 0x01, (byte) 0x00
});
Extension[] defaultExtensions = new Extension[] {
new ServerNameExtension(serverName),
new SupportedVersionsExtension(TlsConstants.HandshakeType.client_hello),
new SupportedGroupsExtension(ecCurve),
new SignatureAlgorithmsExtension(supportedSignatures),
new KeyShareExtension(publicKey, ecCurve, TlsConstants.HandshakeType.client_hello),
};
extensions = new ArrayList<>();
extensions.addAll(List.of(defaultExtensions));
if (pskKeyEstablishmentMode != PskKeyEstablishmentMode.none) {
extensions.add(createPskKeyExchangeModesExtension(pskKeyEstablishmentMode));
}
extensions.addAll(extraExtensions);
ClientHelloPreSharedKeyExtension pskExtension = null;
int extensionsLength = extensions.stream().mapToInt(ext -> ext.getBytes().length).sum();
buffer.putShort((short) extensionsLength);
int pskExtensionStartPosition = -1;
for (Extension extension: extensions) {
if (extension instanceof ClientHelloPreSharedKeyExtension) {
pskExtension = (ClientHelloPreSharedKeyExtension) extension;
pskExtensionStartPosition = buffer.position();
}
buffer.put(extension.getBytes());
}
this.pskExtensionStartPosition = pskExtensionStartPosition; // Copy value into member field, necessary because field is final.
buffer.limit(buffer.position());
int clientHelloLength = buffer.position() - 4;
buffer.putShort(2, (short) clientHelloLength);
data = new byte[clientHelloLength + 4];
buffer.rewind();
buffer.get(data);
if (pskExtension != null) {
if (binderCalculator == null) {
throw new IllegalArgumentException("BinderCalculator cannot be null when ClientHelloPreSharedKeyExtension is present");
}
pskExtension.calculateBinder(data, pskExtensionStartPosition, binderCalculator);
buffer.position(pskExtensionStartPosition);
buffer.put(pskExtension.getBytes());
buffer.rewind();
buffer.get(data);
}
}
private PskKeyExchangeModesExtension createPskKeyExchangeModesExtension(PskKeyEstablishmentMode pskKeyEstablishmentMode) {
switch (pskKeyEstablishmentMode) {
case PSKonly:
return new PskKeyExchangeModesExtension(TlsConstants.PskKeyExchangeMode.psk_ke);
case PSKwithDHE:
return new PskKeyExchangeModesExtension(TlsConstants.PskKeyExchangeMode.psk_dhe_ke);
case both:
return new PskKeyExchangeModesExtension(TlsConstants.PskKeyExchangeMode.psk_ke, TlsConstants.PskKeyExchangeMode.psk_dhe_ke);
default:
throw new IllegalArgumentException();
}
}
@Override
public TlsConstants.HandshakeType getType() {
return TlsConstants.HandshakeType.client_hello;
}
@Override
public byte[] getBytes() {
return data;
}
public byte[] getClientRandom() {
return clientRandom;
}
public List getCipherSuites() {
return cipherSuites;
}
public List getExtensions() {
return extensions;
}
/**
* Returns the start position of the PreSharedKeyExtension in the serialized ClientHello. This is needed for computing binders.
* @return the start position or -1 if not present.
*/
public int getPskExtensionStartPosition() {
return pskExtensionStartPosition;
}
@Override
public String toString() {
return "ClientHello["
+ cipherSuites.stream().map(cs -> cs.toString()).collect(Collectors.joining(",")) + "|"
+ extensions.stream().map(ex -> ex.toString()).collect(Collectors.joining(","))
+ "]";
}
}
