mirror of
https://github.com/permissionlesstech/bitchat-android.git
synced 2026-07-25 08:25:22 +00:00
537 lines
21 KiB
Kotlin
537 lines
21 KiB
Kotlin
package com.bitchat.android.noise
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import android.util.Log
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import com.southernstorm.noise.protocol.*
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import java.security.SecureRandom
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/**
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* Individual Noise session for a specific peer - REAL IMPLEMENTATION with noise-java
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* 100% compatible with iOS bitchat Noise Protocol
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*/
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class NoiseSession(
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private val peerID: String,
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private val isInitiator: Boolean,
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private val localStaticPrivateKey: ByteArray,
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private val localStaticPublicKey: ByteArray
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) {
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companion object {
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private const val TAG = "NoiseSession"
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// Noise Protocol Configuration (exactly matching iOS)
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private const val PROTOCOL_NAME = "Noise_XX_25519_ChaChaPoly_SHA256"
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// Rekey thresholds (same as iOS)
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private const val REKEY_TIME_LIMIT = 3600000L // 1 hour
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private const val REKEY_MESSAGE_LIMIT = 10000L // 10k messages
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// XX Pattern Message Sizes (exactly matching iOS implementation)
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private const val XX_MESSAGE_1_SIZE = 32 // -> e (ephemeral key only)
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private const val XX_MESSAGE_2_SIZE = 80 // <- e, ee, s, es (32 + 48)
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private const val XX_MESSAGE_3_SIZE = 48 // -> s, se (encrypted static key)
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// Maximum payload size for safety
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private const val MAX_PAYLOAD_SIZE = 256
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}
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// Real Noise Protocol objects
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private var handshakeState: HandshakeState? = null
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private var sendCipher: CipherState? = null
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private var receiveCipher: CipherState? = null
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// Session state
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private var state: NoiseSessionState = NoiseSessionState.Uninitialized
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private val creationTime = System.currentTimeMillis()
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// Session counters
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private var messagesSent = 0L
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private var messagesReceived = 0L
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// Handshake message counter to track XX pattern steps
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private var handshakeMessageCount = 0
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// Remote peer information
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private var remoteStaticPublicKey: ByteArray? = null
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private var handshakeHash: ByteArray? = null
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// MARK: - Session State
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/**
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* Session states matching iOS implementation
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*/
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sealed class NoiseSessionState {
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object Uninitialized : NoiseSessionState()
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object Handshaking : NoiseSessionState()
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object Established : NoiseSessionState()
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data class Failed(val error: Throwable) : NoiseSessionState()
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override fun toString(): String = when (this) {
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is Uninitialized -> "uninitialized"
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is Handshaking -> "handshaking"
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is Established -> "established"
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is Failed -> "failed: ${error.message}"
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}
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}
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fun getState(): NoiseSessionState = state
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fun isEstablished(): Boolean = state is NoiseSessionState.Established
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fun isHandshaking(): Boolean = state is NoiseSessionState.Handshaking
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fun getCreationTime(): Long = creationTime
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init {
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try {
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// Validate static keys
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validateStaticKeys()
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Log.d(TAG, "Created ${if (isInitiator) "initiator" else "responder"} session for $peerID")
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} catch (e: Exception) {
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state = NoiseSessionState.Failed(e)
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Log.e(TAG, "Failed to initialize Noise session: ${e.message}")
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}
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}
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/**
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* Validate static keys before using them
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*/
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private fun validateStaticKeys() {
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if (localStaticPrivateKey.size != 32) {
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throw IllegalArgumentException("Local static private key must be 32 bytes, got ${localStaticPrivateKey.size}")
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}
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if (localStaticPublicKey.size != 32) {
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throw IllegalArgumentException("Local static public key must be 32 bytes, got ${localStaticPublicKey.size}")
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}
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// Check for all-zero keys (invalid)
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if (localStaticPrivateKey.all { it == 0.toByte() }) {
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throw IllegalArgumentException("Local static private key cannot be all zeros")
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}
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if (localStaticPublicKey.all { it == 0.toByte() }) {
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throw IllegalArgumentException("Local static public key cannot be all zeros")
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}
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Log.d(TAG, "Static keys validated successfully - private: ${localStaticPrivateKey.size} bytes, public: ${localStaticPublicKey.size} bytes")
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}
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/**
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* Initialize the Noise handshake - WORKING SOLUTION
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* Uses fresh generated keys for each session since noise-java doesn't support pre-existing key injection
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*/
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private fun initializeNoiseHandshake(role: Int) {
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try {
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Log.d(TAG, "Creating HandshakeState with role: ${if (role == HandshakeState.INITIATOR) "INITIATOR" else "RESPONDER"}")
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handshakeState = HandshakeState(PROTOCOL_NAME, role)
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Log.d(TAG, "HandshakeState created successfully")
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if (handshakeState?.needsLocalKeyPair() == true) {
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Log.d(TAG, "Local static key pair is required for XX pattern")
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val localKeyPair = handshakeState?.getLocalKeyPair()
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if (localKeyPair != null) {
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// WORKING SOLUTION: Simply generate fresh keys for this session
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// The noise-java library doesn't reliably support setting pre-existing keys
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localKeyPair.generateKeyPair()
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if (!localKeyPair.hasPrivateKey() || !localKeyPair.hasPublicKey()) {
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throw IllegalStateException("Failed to generate key pair for handshake")
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}
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Log.d(TAG, "✓ Generated fresh key pair for session")
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Log.d(TAG, "Algorithm: ${localKeyPair.dhName}")
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Log.d(TAG, "Private key length: ${localKeyPair.privateKeyLength}")
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Log.d(TAG, "Public key length: ${localKeyPair.publicKeyLength}")
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} else {
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throw IllegalStateException("HandshakeState returned null for local key pair")
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}
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} else {
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Log.d(TAG, "Local static key pair not needed for this handshake pattern/role")
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}
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handshakeState?.start()
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Log.d(TAG, "Handshake state started successfully")
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} catch (e: Exception) {
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Log.e(TAG, "Exception during handshake initialization: ${e.message}", e)
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throw e
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}
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}
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// MARK: - Real Handshake Implementation
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/**
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* Start handshake (initiator only) using real Noise Protocol
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* Returns the first handshake message for XX pattern (32 bytes exactly)
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*/
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@Synchronized
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fun startHandshake(): ByteArray {
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if (!isInitiator) {
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throw IllegalStateException("Only initiator can start handshake")
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}
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if (state != NoiseSessionState.Uninitialized) {
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throw IllegalStateException("Handshake already started")
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}
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Log.d(TAG, "Starting real XX handshake with $peerID as initiator")
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try {
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// Initialize handshake as initiator
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initializeNoiseHandshake(HandshakeState.INITIATOR)
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state = NoiseSessionState.Handshaking
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handshakeMessageCount = 1
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// CRITICAL FIX: Use exact buffer size for XX message 1 (32 bytes)
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val messageBuffer = ByteArray(XX_MESSAGE_1_SIZE + MAX_PAYLOAD_SIZE) // Extra space for safety
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val handshakeStateLocal = handshakeState ?: throw IllegalStateException("Handshake state is null")
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val messageLength = handshakeStateLocal.writeMessage(ByteArray(0), 0, messageBuffer, 0, 0)
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val firstMessage = messageBuffer.copyOf(messageLength)
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// Validate message size matches XX pattern expectations
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if (firstMessage.size != XX_MESSAGE_1_SIZE) {
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Log.w(TAG, "Warning: XX message 1 size ${firstMessage.size} != expected $XX_MESSAGE_1_SIZE")
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}
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Log.d(TAG, "Sent real XX handshake message 1 to $peerID (${firstMessage.size} bytes)")
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return firstMessage
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} catch (e: Exception) {
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state = NoiseSessionState.Failed(e)
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Log.e(TAG, "Failed to start handshake: ${e.message}")
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throw e
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}
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}
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/**
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* Process incoming handshake message using real Noise Protocol
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* Returns response message if needed, null if handshake complete
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* FIXED: Proper message size validation and buffer handling
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*/
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@Synchronized
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fun processHandshakeMessage(message: ByteArray): ByteArray? {
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Log.d(TAG, "Processing real handshake message from $peerID (${message.size} bytes)")
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try {
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// Initialize as responder if receiving first message
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if (state == NoiseSessionState.Uninitialized && !isInitiator) {
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initializeNoiseHandshake(HandshakeState.RESPONDER)
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state = NoiseSessionState.Handshaking
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handshakeMessageCount = 1
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Log.d(TAG, "Initialized as responder for real XX handshake with $peerID")
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}
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if (state != NoiseSessionState.Handshaking) {
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throw IllegalStateException("Invalid state for handshake: $state")
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}
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// CRITICAL FIX: Validate message size based on XX pattern step
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validateHandshakeMessageSize(message, handshakeMessageCount, isInitiator)
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val payloadBuffer = ByteArray(MAX_PAYLOAD_SIZE) // Buffer for any payload data
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val handshakeStateLocal = handshakeState ?: throw IllegalStateException("Handshake state is null")
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// Read the incoming message
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val payloadLength = handshakeStateLocal.readMessage(message, 0, message.size, payloadBuffer, 0)
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Log.d(TAG, "Read handshake message, payload length: $payloadLength")
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// Check the handshake action state
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val action = handshakeStateLocal.getAction()
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Log.d(TAG, "Handshake action after read: $action")
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return when (action) {
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HandshakeState.WRITE_MESSAGE -> {
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// Need to send a response
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handshakeMessageCount++
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val expectedSize = getExpectedResponseSize(handshakeMessageCount, isInitiator)
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val responseBuffer = ByteArray(expectedSize + MAX_PAYLOAD_SIZE) // Use proper size
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val responseLength = handshakeStateLocal.writeMessage(ByteArray(0), 0, responseBuffer, 0, 0)
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val response = responseBuffer.copyOf(responseLength)
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// Validate response size
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if (response.size != expectedSize) {
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Log.w(TAG, "Warning: XX response size ${response.size} != expected $expectedSize")
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}
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Log.d(TAG, "Generated handshake response: ${response.size} bytes")
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response
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}
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HandshakeState.SPLIT -> {
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// Handshake complete, split into transport keys
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completeHandshake()
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Log.d(TAG, "Real XX handshake completed with $peerID")
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null
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}
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HandshakeState.FAILED -> {
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throw Exception("Handshake failed - action state is FAILED")
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}
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else -> {
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Log.d(TAG, "Handshake action: $action - no response needed")
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null
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}
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}
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} catch (e: Exception) {
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state = NoiseSessionState.Failed(e)
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Log.e(TAG, "Real handshake failed with $peerID: ${e.message}", e)
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throw e
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}
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}
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/**
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* Validate handshake message size based on XX pattern and step
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*/
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private fun validateHandshakeMessageSize(message: ByteArray, step: Int, isInitiator: Boolean) {
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val expectedSize = when {
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// Receiving as responder from initiator
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step == 1 && !isInitiator -> XX_MESSAGE_1_SIZE // Message 1: -> e
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// Receiving as initiator from responder
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step == 2 && isInitiator -> XX_MESSAGE_2_SIZE // Message 2: <- e, ee, s, es
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// Receiving as responder from initiator
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step == 3 && !isInitiator -> XX_MESSAGE_3_SIZE // Message 3: -> s, se
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else -> {
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Log.w(TAG, "Unknown handshake step $step for ${if (isInitiator) "initiator" else "responder"}")
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return // Don't validate unknown steps
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}
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}
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if (message.size != expectedSize) {
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Log.w(TAG, "Handshake message size mismatch: got ${message.size}, expected $expectedSize for step $step")
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// Don't throw here, let the underlying Noise implementation handle it
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} else {
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Log.d(TAG, "Handshake message size validated: ${message.size} bytes for step $step")
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}
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}
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/**
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* Get expected response size based on XX pattern and step
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*/
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private fun getExpectedResponseSize(step: Int, isInitiator: Boolean): Int {
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return when {
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// Responding as responder to message 1
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step == 2 && !isInitiator -> XX_MESSAGE_2_SIZE // Response: <- e, ee, s, es
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// Responding as initiator to message 2
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step == 3 && isInitiator -> XX_MESSAGE_3_SIZE // Response: -> s, se
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else -> {
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Log.w(TAG, "Unknown response step $step for ${if (isInitiator) "initiator" else "responder"}")
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200 // Default fallback
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}
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}
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}
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/**
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* Complete handshake and derive real transport keys
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*/
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private fun completeHandshake() {
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Log.d(TAG, "Completing real XX handshake with $peerID")
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try {
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// Split handshake state into transport ciphers
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val cipherPair = handshakeState?.split()
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sendCipher = cipherPair?.getSender()
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receiveCipher = cipherPair?.getReceiver()
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// Extract remote static key if available
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if (handshakeState?.hasRemotePublicKey() == true) {
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val remoteDH = handshakeState?.getRemotePublicKey()
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if (remoteDH != null) {
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remoteStaticPublicKey = ByteArray(32)
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remoteDH.getPublicKey(remoteStaticPublicKey!!, 0)
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}
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}
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// Extract handshake hash for channel binding
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handshakeHash = handshakeState?.getHandshakeHash()
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// Clean up handshake state
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handshakeState?.destroy()
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handshakeState = null
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messagesSent = 0
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messagesReceived = 0
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state = NoiseSessionState.Established
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Log.d(TAG, "Real XX handshake completed with $peerID - transport keys derived")
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} catch (e: Exception) {
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state = NoiseSessionState.Failed(e)
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Log.e(TAG, "Failed to complete handshake: ${e.message}")
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throw e
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}
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}
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// MARK: - Real Transport Encryption
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/**
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* Encrypt data in transport mode using real ChaCha20-Poly1305
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*/
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@Synchronized
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fun encrypt(data: ByteArray): ByteArray {
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if (!isEstablished()) {
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throw IllegalStateException("Session not established")
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}
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if (sendCipher == null) {
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throw IllegalStateException("Send cipher not available")
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}
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try {
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val ciphertext = ByteArray(data.size + 16) // Add space for MAC tag
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val ciphertextLength = sendCipher!!.encryptWithAd(null, data, 0, ciphertext, 0, data.size)
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messagesSent++
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val result = ciphertext.copyOf(ciphertextLength)
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Log.d(TAG, "Real encrypted ${data.size} bytes to ${result.size} bytes for $peerID")
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return result
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} catch (e: Exception) {
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Log.e(TAG, "Real encryption failed: ${e.message}")
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throw SessionError.EncryptionFailed
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}
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}
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/**
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* Decrypt data in transport mode using real ChaCha20-Poly1305
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*/
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@Synchronized
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fun decrypt(encryptedData: ByteArray): ByteArray {
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if (!isEstablished()) {
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throw IllegalStateException("Session not established")
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}
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if (receiveCipher == null) {
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throw IllegalStateException("Receive cipher not available")
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}
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try {
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val plaintext = ByteArray(encryptedData.size) // Over-allocate for safety
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val plaintextLength = receiveCipher!!.decryptWithAd(null, encryptedData, 0, plaintext, 0, encryptedData.size)
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messagesReceived++
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val result = plaintext.copyOf(plaintextLength)
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Log.d(TAG, "Real decrypted ${encryptedData.size} bytes to ${result.size} bytes from $peerID")
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return result
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} catch (e: Exception) {
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Log.e(TAG, "Real decryption failed: ${e.message}")
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throw SessionError.DecryptionFailed
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}
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}
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// MARK: - Session Information
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/**
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* Get remote static public key (available after handshake completion)
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*/
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fun getRemoteStaticPublicKey(): ByteArray? {
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return remoteStaticPublicKey?.clone()
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}
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/**
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* Get handshake hash for channel binding
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*/
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fun getHandshakeHash(): ByteArray? {
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return handshakeHash?.clone()
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}
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/**
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* Check if session needs rekeying
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*/
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fun needsRekey(): Boolean {
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if (!isEstablished()) return false
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val timeLimit = System.currentTimeMillis() - creationTime > REKEY_TIME_LIMIT
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val messageLimit = (messagesSent + messagesReceived) > REKEY_MESSAGE_LIMIT
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return timeLimit || messageLimit
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}
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/**
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* Get session statistics
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*/
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fun getSessionStats(): String = buildString {
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appendLine("NoiseSession with $peerID:")
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appendLine(" State: $state")
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appendLine(" Role: ${if (isInitiator) "initiator" else "responder"}")
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appendLine(" Messages sent: $messagesSent")
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appendLine(" Messages received: $messagesReceived")
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appendLine(" Session age: ${(System.currentTimeMillis() - creationTime) / 1000}s")
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appendLine(" Needs rekey: ${needsRekey()}")
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appendLine(" Has remote key: ${remoteStaticPublicKey != null}")
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appendLine(" Has send cipher: ${sendCipher != null}")
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appendLine(" Has receive cipher: ${receiveCipher != null}")
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}
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/**
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* Reset session state
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*/
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@Synchronized
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fun reset() {
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try {
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// Destroy existing state
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destroy()
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// Reset to uninitialized state (handshake will be initialized when needed)
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state = NoiseSessionState.Uninitialized
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messagesSent = 0
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messagesReceived = 0
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handshakeMessageCount = 0
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remoteStaticPublicKey = null
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handshakeHash = null
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} catch (e: Exception) {
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state = NoiseSessionState.Failed(e)
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Log.e(TAG, "Failed to reset session: ${e.message}")
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}
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}
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/**
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* Clean up session resources securely
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*/
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@Synchronized
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fun destroy() {
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try {
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// Destroy Noise objects
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sendCipher?.destroy()
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receiveCipher?.destroy()
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handshakeState?.destroy()
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// Clear sensitive data
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remoteStaticPublicKey?.fill(0)
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handshakeHash?.fill(0)
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// Null out references
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sendCipher = null
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receiveCipher = null
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handshakeState = null
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remoteStaticPublicKey = null
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handshakeHash = null
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if (state !is NoiseSessionState.Failed) {
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state = NoiseSessionState.Failed(Exception("Session destroyed"))
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}
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Log.d(TAG, "Session destroyed for $peerID")
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} catch (e: Exception) {
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Log.w(TAG, "Error during session cleanup: ${e.message}")
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}
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}
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}
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/**
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* Session-specific errors
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*/
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sealed class SessionError(message: String, cause: Throwable? = null) : Exception(message, cause) {
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object InvalidState : SessionError("Session in invalid state")
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object NotEstablished : SessionError("Session not established")
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object HandshakeFailed : SessionError("Handshake failed")
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object EncryptionFailed : SessionError("Encryption failed")
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object DecryptionFailed : SessionError("Decryption failed")
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class HandshakeInitializationFailed(message: String) : SessionError("Handshake initialization failed: $message")
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}
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