fix: critical MLS security fixes for Marmot protocol (RFC 9420 compliance)
Phase 1 - Critical/High cryptographic fixes: - Fix sender data nonce reuse: derive key/nonce from ciphertext sample per §6.3.1 - Add PrivateContentAAD binding (group_id, epoch, content_type) per §6.3.2 - Add SenderDataAAD binding per §6.3.1 - Fix KDFLabel encoding: use TLS fixed-width (putOpaque1/putOpaque4) not QUIC VarInt - Add reuse_guard (4-byte random XOR into nonce) per §6.3.1 - Fix parent hash verification: capture sibling hashes before UpdatePath applied - Fix Welcome confirmation tag: use HMAC instead of ExpandWithLabel - Make confirmation tag mandatory in processCommit (was nullable) - Fix off-by-one in path secret derivation during processCommit - Fix TokenEncryption: extract 32-byte x-only pubkey from 33-byte compressed key - Fix SELF_REMOVE proposal type: move from 0x0008 to 0xF001 (private-use range) Phase 2 - Protocol compliance and thread safety: - Validate KeyPackage ciphersuite is supported (0x0001 only) - Synchronize KeyPackageRotationManager read operations with mutex - Synchronize EpochCommitTracker with lock object - Synchronize processedEventIds with lock in MarmotInboundProcessor - Synchronize MlsGroupManager encrypt/decrypt with mutex - Synchronize MarmotSubscriptionManager read methods - Require unresolved proposal references to error per §12.4.2 Phase 3 - Hardening: - Add path traversal validation in AndroidMlsGroupStateStore (hex-only groupId) - Bind nostrGroupId as AAD in outer ChaCha20-Poly1305 encryption - Track failed events in dedup set to prevent CPU exhaustion - Validate nostrGroupId in processWelcome against Welcome event's own h tag - Validate sender leaf index bounds during decryption Phase 4 - Low priority fixes: - Fix externalJoin: compute confirmedTranscriptHash and interimTranscriptHash - Add snapshot methods for non-suspend filter access https://claude.ai/code/session_017SjKXS4Vpu4xRg9zHTgpmC
This commit is contained in:
Claude
@@ -1865,7 +1865,7 @@ class Account(
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* Check if a KeyPackage has been published, either locally generated
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* in this session or found in the local cache from a previous session.
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*/
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fun hasPublishedKeyPackage(): Boolean {
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suspend fun hasPublishedKeyPackage(): Boolean {
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// Check in-memory bundles first (current session)
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val manager = marmotManager
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if (manager != null && manager.hasActiveKeyPackages()) return true
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+11
-1
@@ -42,7 +42,17 @@ class AndroidMlsGroupStateStore(
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private val rootDir: File,
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private val encryption: KeyStoreEncryption = KeyStoreEncryption(),
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) : MlsGroupStateStore {
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private fun groupDir(nostrGroupId: String): File = File(rootDir, "mls_groups/$nostrGroupId")
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private fun groupDir(nostrGroupId: String): File {
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// Validate nostrGroupId is a hex string to prevent path traversal
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require(nostrGroupId.matches(HEX_PATTERN)) {
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"Invalid nostrGroupId: must be a hex string"
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}
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return File(rootDir, "mls_groups/$nostrGroupId")
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}
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companion object {
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private val HEX_PATTERN = Regex("^[0-9a-fA-F]+$")
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}
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private fun stateFile(nostrGroupId: String): File = File(groupDir(nostrGroupId), "state")
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+2
-2
@@ -55,12 +55,12 @@ class MarmotGroupEventsEoseManager(
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val fallbackRelays = key.account.homeRelays.flow.value
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// Per-group kind:445 filters — route each to the group's own relays
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val groupStates = manager.subscriptionManager.activeGroupIds()
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val groupStates = manager.subscriptionManager.activeGroupIdsSnapshot()
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for (groupId in groupStates) {
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val filter =
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manager.subscriptionManager.let { sub ->
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// Build the filter for this specific group
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val groupFilters = sub.activeGroupFilters()
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val groupFilters = sub.activeGroupFiltersSnapshot()
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// activeGroupFilters() returns one filter per group; match by tag content
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groupFilters.find { f ->
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f.tags?.any { it.value?.contains(groupId) == true } == true
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+1
-1
@@ -1464,7 +1464,7 @@ class AccountViewModel(
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account.publishMarmotKeyPackage()
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}
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fun hasPublishedKeyPackage(): Boolean = account.hasPublishedKeyPackage()
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suspend fun hasPublishedKeyPackage(): Boolean = account.hasPublishedKeyPackage()
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suspend fun leaveMarmotGroup(nostrGroupId: String) {
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val relays = marmotGroupRelays(nostrGroupId)
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+2
-2
@@ -301,13 +301,13 @@ class MarmotManager(
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/**
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* Check if KeyPackage rotation is needed.
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*/
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fun needsKeyPackageRotation(): Boolean = keyPackageRotationManager.needsRotation()
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suspend fun needsKeyPackageRotation(): Boolean = keyPackageRotationManager.needsRotation()
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/**
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* Check if there are active (locally generated) KeyPackages.
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* Returns true if at least one KeyPackage has been generated and not yet consumed.
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*/
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fun hasActiveKeyPackages(): Boolean = keyPackageRotationManager.hasActiveKeyPackages()
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suspend fun hasActiveKeyPackages(): Boolean = keyPackageRotationManager.hasActiveKeyPackages()
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/**
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* Check if a specific group membership exists.
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+35
-16
@@ -126,6 +126,7 @@ class MarmotInboundProcessor(
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private val keyPackageRotationManager: KeyPackageRotationManager,
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) {
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private val commitTracker = CommitOrdering.EpochCommitTracker()
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private val processedIdsLock = Any()
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private val processedEventIds = LinkedHashSet<String>()
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companion object {
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@@ -153,11 +154,13 @@ class MarmotInboundProcessor(
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* @return the processing result
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*/
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suspend fun processGroupEvent(groupEvent: GroupEvent): GroupEventResult {
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// Deduplicate already-processed events
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// Deduplicate already-processed events (thread-safe)
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val eventId = groupEvent.id
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if (eventId in processedEventIds) {
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val gId = groupEvent.groupId()
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return GroupEventResult.Duplicate(gId ?: "")
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synchronized(processedIdsLock) {
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if (eventId in processedEventIds) {
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val gId = groupEvent.groupId()
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return GroupEventResult.Duplicate(gId ?: "")
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}
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}
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val groupId =
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@@ -185,8 +188,8 @@ class MarmotInboundProcessor(
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GroupEventResult.Error(groupId, "Failed to process GroupEvent: ${e.message}", e)
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}
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// Track successfully processed events for deduplication
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if (result !is GroupEventResult.Error) {
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// Track ALL processed events for deduplication (including errors to prevent replay DoS)
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synchronized(processedIdsLock) {
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processedEventIds.add(eventId)
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// Trim the set if it exceeds the max size
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if (processedEventIds.size > MAX_PROCESSED_IDS) {
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@@ -223,8 +226,19 @@ class MarmotInboundProcessor(
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nostrGroupId: HexKey,
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): WelcomeResult =
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try {
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// Validate the caller-provided nostrGroupId matches the Welcome event's own h tag
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val eventGroupId = welcomeEvent.nostrGroupId()
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if (eventGroupId != null && eventGroupId != nostrGroupId) {
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return WelcomeResult.Error(
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"nostrGroupId mismatch: caller=$nostrGroupId, event=$eventGroupId",
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)
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}
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val welcomeBytes = Base64.decode(welcomeEvent.welcomeBase64())
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val keyPackageEventId = welcomeEvent.keyPackageEventId()
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if (keyPackageEventId == null) {
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return WelcomeResult.Error("WelcomeEvent missing KeyPackage event ID tag")
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}
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// Find the KeyPackageBundle that was consumed
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val bundle =
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@@ -381,14 +395,19 @@ class MarmotInboundProcessor(
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WireFormat.PUBLIC_MESSAGE -> {
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val pubMsg = PublicMessage.decodeTls(TlsReader(mlsMessage.payload))
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groupManager.processCommit(
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nostrGroupId = groupId,
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commitBytes = pubMsg.content,
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senderLeafIndex = pubMsg.sender.leafIndex,
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confirmationTag = pubMsg.confirmationTag,
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)
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val group = groupManager.getGroup(groupId)
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GroupEventResult.CommitProcessed(groupId, group?.epoch ?: 0)
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val tag = pubMsg.confirmationTag
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if (tag == null) {
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GroupEventResult.Error(groupId, "PublicMessage commit missing confirmation_tag")
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} else {
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groupManager.processCommit(
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nostrGroupId = groupId,
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commitBytes = pubMsg.content,
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senderLeafIndex = pubMsg.sender.leafIndex,
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confirmationTag = tag,
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)
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val group = groupManager.getGroup(groupId)
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GroupEventResult.CommitProcessed(groupId, group?.epoch ?: 0)
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}
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}
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else -> {
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@@ -413,7 +432,7 @@ class MarmotInboundProcessor(
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// Try current epoch key first
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try {
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val exporterKey = groupManager.exporterSecret(groupId)
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return GroupEventEncryption.decrypt(encryptedContent, exporterKey)
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return GroupEventEncryption.decrypt(encryptedContent, exporterKey, groupId)
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} catch (_: Exception) {
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// Current epoch key failed — try retained epoch keys
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}
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@@ -422,7 +441,7 @@ class MarmotInboundProcessor(
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val retainedKeys = groupManager.retainedExporterSecrets(groupId)
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for (retainedKey in retainedKeys) {
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try {
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return GroupEventEncryption.decrypt(encryptedContent, retainedKey)
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return GroupEventEncryption.decrypt(encryptedContent, retainedKey, groupId)
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} catch (_: Exception) {
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// This retained key didn't work — try the next one
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}
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+2
-2
@@ -90,7 +90,7 @@ class MarmotOutboundProcessor(
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// Step 2: Outer ChaCha20-Poly1305 encryption
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val exporterKey = groupManager.exporterSecret(nostrGroupId)
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val encryptedContent = GroupEventEncryption.encrypt(mlsCiphertext, exporterKey)
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val encryptedContent = GroupEventEncryption.encrypt(mlsCiphertext, exporterKey, nostrGroupId)
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// Step 3: Build the GroupEvent template
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val template =
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@@ -125,7 +125,7 @@ class MarmotOutboundProcessor(
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): OutboundGroupEvent {
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// Outer ChaCha20-Poly1305 encryption of the MLS commit
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val exporterKey = groupManager.exporterSecret(nostrGroupId)
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val encryptedContent = GroupEventEncryption.encrypt(commitBytes, exporterKey)
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val encryptedContent = GroupEventEncryption.encrypt(commitBytes, exporterKey, nostrGroupId)
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// Build the GroupEvent template
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val template =
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+37
-13
@@ -107,21 +107,24 @@ class MarmotSubscriptionManager(
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/**
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* Returns all active group IDs being tracked.
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* Non-suspend snapshot version for callers that cannot be suspend (e.g., filter builders).
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*/
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fun activeGroupIds(): Set<HexKey> = groupSubscriptions.filter { it.value.active }.keys
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fun activeGroupIdsSnapshot(): Set<HexKey> = groupSubscriptions.filter { it.value.active }.keys.toSet()
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/**
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* Returns all active group IDs being tracked.
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*/
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suspend fun activeGroupIds(): Set<HexKey> = mutex.withLock { groupSubscriptions.filter { it.value.active }.keys.toSet() }
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/**
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* Check if a group is currently subscribed.
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*/
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fun isSubscribed(nostrGroupId: HexKey): Boolean = groupSubscriptions[nostrGroupId]?.active == true
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suspend fun isSubscribed(nostrGroupId: HexKey): Boolean = mutex.withLock { groupSubscriptions[nostrGroupId]?.active == true }
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/**
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* Build filters for all active group subscriptions.
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*
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* Returns one [Filter] per active group (kind:445 filtered by `h` tag),
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* using the tracked `since` timestamp for pagination.
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* Non-suspend snapshot version of activeGroupFilters for callers that cannot be suspend.
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*/
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fun activeGroupFilters(): List<Filter> =
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fun activeGroupFiltersSnapshot(): List<Filter> =
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groupSubscriptions.values
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.filter { it.active }
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.map { state ->
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@@ -132,17 +135,38 @@ class MarmotSubscriptionManager(
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}
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}
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/**
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* Build filters for all active group subscriptions.
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*
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* Returns one [Filter] per active group (kind:445 filtered by `h` tag),
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* using the tracked `since` timestamp for pagination.
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*/
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suspend fun activeGroupFilters(): List<Filter> =
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mutex.withLock {
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groupSubscriptions.values
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.filter { it.active }
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.map { state ->
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if (state.since != null) {
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MarmotFilters.groupEventsByGroupIdSince(state.nostrGroupId, state.since!!)
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} else {
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MarmotFilters.groupEventsByGroupId(state.nostrGroupId)
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}
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}
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}
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/**
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* Build the gift wrap filter for receiving Welcome messages.
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*
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* Returns a single filter for kind:1059 addressed to the user's pubkey,
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* using the tracked `since` timestamp for pagination.
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*/
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fun giftWrapFilter(): Filter =
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if (giftWrapSince != null) {
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MarmotFilters.giftWrapsForUserSince(userPubKey, giftWrapSince!!)
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} else {
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MarmotFilters.giftWrapsForUser(userPubKey)
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suspend fun giftWrapFilter(): Filter =
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mutex.withLock {
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if (giftWrapSince != null) {
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MarmotFilters.giftWrapsForUserSince(userPubKey, giftWrapSince!!)
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} else {
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MarmotFilters.giftWrapsForUser(userPubKey)
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}
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}
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/**
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@@ -174,7 +198,7 @@ class MarmotSubscriptionManager(
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* The platform layer should send these filters to the relay client
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* whenever subscriptions change or on reconnection.
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*/
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fun buildFilters(): List<Filter> {
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suspend fun buildFilters(): List<Filter> {
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val filters = mutableListOf<Filter>()
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filters.addAll(activeGroupFilters())
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filters.add(giftWrapFilter())
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+9
-7
@@ -106,15 +106,17 @@ class KeyPackageRotationManager {
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* Get the active bundle for a d-tag slot.
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* Used when processing a Welcome that references one of our KeyPackages.
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*/
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fun getBundle(dTagSlot: String): KeyPackageBundle? = activeBundles[dTagSlot]
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suspend fun getBundle(dTagSlot: String): KeyPackageBundle? = mutex.withLock { activeBundles[dTagSlot] }
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/**
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* Find the bundle whose KeyPackage reference matches the given ref.
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* Used when we receive a Welcome and need to find the matching bundle.
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*/
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fun findBundleByRef(keyPackageRef: ByteArray): KeyPackageBundle? =
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activeBundles.values.find { bundle ->
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bundle.keyPackage.reference().contentEquals(keyPackageRef)
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suspend fun findBundleByRef(keyPackageRef: ByteArray): KeyPackageBundle? =
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mutex.withLock {
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activeBundles.values.find { bundle ->
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bundle.keyPackage.reference().contentEquals(keyPackageRef)
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}
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}
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/**
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@@ -146,7 +148,7 @@ class KeyPackageRotationManager {
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/**
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* Get the d-tag slots that need rotation (KeyPackage was consumed).
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*/
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fun pendingRotationSlots(): Set<String> = pendingRotations.toSet()
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suspend fun pendingRotationSlots(): Set<String> = mutex.withLock { pendingRotations.toSet() }
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/**
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* Clear a slot from the pending rotation set after a new KeyPackage
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@@ -160,13 +162,13 @@ class KeyPackageRotationManager {
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/**
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* Check if any slots need rotation.
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*/
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fun needsRotation(): Boolean = pendingRotations.isNotEmpty()
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suspend fun needsRotation(): Boolean = mutex.withLock { pendingRotations.isNotEmpty() }
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/**
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* Check if there are any active (non-consumed) KeyPackage bundles.
|
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* Returns true if at least one slot has been generated and not yet consumed.
|
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*/
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fun hasActiveKeyPackages(): Boolean = activeBundles.isNotEmpty()
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suspend fun hasActiveKeyPackages(): Boolean = mutex.withLock { activeBundles.isNotEmpty() }
|
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|
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/**
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* Rotate a consumed slot: generate a new KeyPackage for the same d-tag.
|
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|
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+19
-8
@@ -82,6 +82,7 @@ object CommitOrdering {
|
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* to determine which commit wins for each (group, epoch).
|
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*/
|
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class EpochCommitTracker {
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private val lock = Any()
|
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private val pendingByGroupEpoch = mutableMapOf<GroupEpochKey, MutableList<GroupEvent>>()
|
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|
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companion object {
|
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@@ -100,7 +101,7 @@ object CommitOrdering {
|
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groupId: String,
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epoch: Long,
|
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commit: GroupEvent,
|
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) {
|
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) = synchronized(lock) {
|
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val key = GroupEpochKey(groupId, epoch)
|
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pendingByGroupEpoch.getOrPut(key) { mutableListOf() }.add(commit)
|
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|
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@@ -122,7 +123,10 @@ object CommitOrdering {
|
||||
fun pendingForEpoch(
|
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groupId: String,
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epoch: Long,
|
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): List<GroupEvent> = pendingByGroupEpoch[GroupEpochKey(groupId, epoch)] ?: emptyList()
|
||||
): List<GroupEvent> =
|
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synchronized(lock) {
|
||||
pendingByGroupEpoch[GroupEpochKey(groupId, epoch)]?.toList() ?: emptyList()
|
||||
}
|
||||
|
||||
/**
|
||||
* Resolves the winning commit for a specific group and epoch.
|
||||
@@ -134,7 +138,10 @@ object CommitOrdering {
|
||||
fun resolve(
|
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groupId: String,
|
||||
epoch: Long,
|
||||
): GroupEvent? = selectWinner(pendingByGroupEpoch[GroupEpochKey(groupId, epoch)] ?: emptyList())
|
||||
): GroupEvent? =
|
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synchronized(lock) {
|
||||
selectWinner(pendingByGroupEpoch[GroupEpochKey(groupId, epoch)] ?: emptyList())
|
||||
}
|
||||
|
||||
/**
|
||||
* Clears pending commits for a (group, epoch) after it has been resolved.
|
||||
@@ -142,20 +149,24 @@ object CommitOrdering {
|
||||
fun clearEpoch(
|
||||
groupId: String,
|
||||
epoch: Long,
|
||||
) {
|
||||
) = synchronized(lock) {
|
||||
pendingByGroupEpoch.remove(GroupEpochKey(groupId, epoch))
|
||||
}
|
||||
|
||||
/**
|
||||
* Returns all (group, epoch) keys that have pending commits.
|
||||
*/
|
||||
fun pendingGroupEpochs(): Set<GroupEpochKey> = pendingByGroupEpoch.keys.toSet()
|
||||
fun pendingGroupEpochs(): Set<GroupEpochKey> =
|
||||
synchronized(lock) {
|
||||
pendingByGroupEpoch.keys.toSet()
|
||||
}
|
||||
|
||||
/**
|
||||
* Clears all pending state.
|
||||
*/
|
||||
fun clear() {
|
||||
pendingByGroupEpoch.clear()
|
||||
}
|
||||
fun clear() =
|
||||
synchronized(lock) {
|
||||
pendingByGroupEpoch.clear()
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
+8
-4
@@ -36,26 +36,27 @@ import kotlin.io.encoding.ExperimentalEncodingApi
|
||||
* Since the MLS engine is not yet integrated, this helper accepts the 32-byte key as a parameter.
|
||||
*/
|
||||
object GroupEventEncryption {
|
||||
private val EMPTY_AAD = ByteArray(0)
|
||||
|
||||
/**
|
||||
* Encrypts an MLS message for a GroupEvent.
|
||||
*
|
||||
* @param mlsMessageBytes the raw MLS message bytes to encrypt
|
||||
* @param groupKey 32-byte key derived from MLS-Exporter("marmot", "group-event", 32)
|
||||
* @param nostrGroupId hex-encoded group ID bound to the ciphertext via AAD
|
||||
* @return base64-encoded string containing nonce(12) || ciphertext || tag(16)
|
||||
*/
|
||||
@OptIn(ExperimentalEncodingApi::class)
|
||||
fun encrypt(
|
||||
mlsMessageBytes: ByteArray,
|
||||
groupKey: ByteArray,
|
||||
nostrGroupId: String = "",
|
||||
): String {
|
||||
require(groupKey.size == GroupEvent.EXPORTER_KEY_LENGTH) {
|
||||
"Group key must be ${GroupEvent.EXPORTER_KEY_LENGTH} bytes"
|
||||
}
|
||||
|
||||
val aad = nostrGroupId.encodeToByteArray()
|
||||
val nonce = RandomInstance.bytes(GroupEvent.NONCE_LENGTH)
|
||||
val ciphertextWithTag = ChaCha20Poly1305.encrypt(mlsMessageBytes, EMPTY_AAD, nonce, groupKey)
|
||||
val ciphertextWithTag = ChaCha20Poly1305.encrypt(mlsMessageBytes, aad, nonce, groupKey)
|
||||
|
||||
// Prepend nonce to ciphertext+tag
|
||||
val payload = ByteArray(nonce.size + ciphertextWithTag.size)
|
||||
@@ -70,6 +71,7 @@ object GroupEventEncryption {
|
||||
*
|
||||
* @param encryptedContentBase64 base64-encoded content from the GroupEvent
|
||||
* @param groupKey 32-byte key derived from MLS-Exporter("marmot", "group-event", 32)
|
||||
* @param nostrGroupId hex-encoded group ID bound to the ciphertext via AAD
|
||||
* @return decrypted MLS message bytes
|
||||
* @throws IllegalStateException if authentication fails
|
||||
* @throws IllegalArgumentException if content is malformed
|
||||
@@ -78,6 +80,7 @@ object GroupEventEncryption {
|
||||
fun decrypt(
|
||||
encryptedContentBase64: String,
|
||||
groupKey: ByteArray,
|
||||
nostrGroupId: String = "",
|
||||
): ByteArray {
|
||||
require(groupKey.size == GroupEvent.EXPORTER_KEY_LENGTH) {
|
||||
"Group key must be ${GroupEvent.EXPORTER_KEY_LENGTH} bytes"
|
||||
@@ -88,9 +91,10 @@ object GroupEventEncryption {
|
||||
"Payload too short: ${payload.size} bytes, minimum ${GroupEvent.MIN_CONTENT_LENGTH}"
|
||||
}
|
||||
|
||||
val aad = nostrGroupId.encodeToByteArray()
|
||||
val nonce = payload.copyOfRange(0, GroupEvent.NONCE_LENGTH)
|
||||
val ciphertextWithTag = payload.copyOfRange(GroupEvent.NONCE_LENGTH, payload.size)
|
||||
|
||||
return ChaCha20Poly1305.decrypt(ciphertextWithTag, EMPTY_AAD, nonce, groupKey)
|
||||
return ChaCha20Poly1305.decrypt(ciphertextWithTag, aad, nonce, groupKey)
|
||||
}
|
||||
}
|
||||
|
||||
+4
-2
@@ -91,9 +91,11 @@ object TokenEncryption {
|
||||
val padding = RandomInstance.bytes(PADDED_PAYLOAD_SIZE - paddingStart)
|
||||
padding.copyInto(payload, paddingStart)
|
||||
|
||||
// Generate ephemeral keypair for ECDH
|
||||
// Generate ephemeral keypair for ECDH (x-only 32-byte pubkey)
|
||||
val ephemeralPrivKey = RandomInstance.bytes(32)
|
||||
val ephemeralPubKey = Secp256k1Instance.compressedPubKeyFor(ephemeralPrivKey)
|
||||
val compressedPubKey = Secp256k1Instance.compressedPubKeyFor(ephemeralPrivKey)
|
||||
// Extract the 32-byte x-only public key by dropping the SEC1 prefix byte
|
||||
val ephemeralPubKey = compressedPubKey.copyOfRange(1, 33)
|
||||
|
||||
// ECDH: shared_x = sha256(ephemeral_privkey * server_pubkey)
|
||||
val sharedPoint = Secp256k1Instance.pubKeyTweakMulCompact(serverPubKey, ephemeralPrivKey)
|
||||
|
||||
+8
-5
@@ -73,7 +73,10 @@ object MlsCryptoProvider {
|
||||
* opaque context<V> = Context;
|
||||
* } KDFLabel;
|
||||
* ```
|
||||
* Label and context lengths use QUIC-style variable-length integer encoding.
|
||||
* Label and context use TLS variable-length vectors with fixed-width
|
||||
* length prefixes per RFC 9420 Section 8:
|
||||
* opaque label<V> uses a 1-byte length prefix (opaque<7..255>)
|
||||
* opaque context<V> uses a 4-byte length prefix (opaque<0..2^32-1>)
|
||||
*/
|
||||
fun expandWithLabel(
|
||||
secret: ByteArray,
|
||||
@@ -84,8 +87,8 @@ object MlsCryptoProvider {
|
||||
val fullLabel = "MLS 1.0 $label".encodeToByteArray()
|
||||
val hkdfLabel = TlsWriter(4 + fullLabel.size + context.size)
|
||||
hkdfLabel.putUint16(length)
|
||||
hkdfLabel.putOpaqueVarInt(fullLabel)
|
||||
hkdfLabel.putOpaqueVarInt(context)
|
||||
hkdfLabel.putOpaque1(fullLabel)
|
||||
hkdfLabel.putOpaque4(context)
|
||||
return hkdfExpand(secret, hkdfLabel.toByteArray(), length)
|
||||
}
|
||||
|
||||
@@ -103,8 +106,8 @@ object MlsCryptoProvider {
|
||||
val fullLabel = prefix + label
|
||||
val hkdfLabel = TlsWriter(4 + fullLabel.size + context.size)
|
||||
hkdfLabel.putUint16(length)
|
||||
hkdfLabel.putOpaqueVarInt(fullLabel)
|
||||
hkdfLabel.putOpaqueVarInt(context)
|
||||
hkdfLabel.putOpaque1(fullLabel)
|
||||
hkdfLabel.putOpaque4(context)
|
||||
return hkdfExpand(secret, hkdfLabel.toByteArray(), length)
|
||||
}
|
||||
|
||||
|
||||
+195
-72
@@ -498,7 +498,7 @@ class MlsGroup private constructor(
|
||||
// --- Message Encryption ---
|
||||
|
||||
/**
|
||||
* Encrypt an application message as a PrivateMessage.
|
||||
* Encrypt an application message as a PrivateMessage (RFC 9420 Section 6.3).
|
||||
*/
|
||||
fun encrypt(plaintext: ByteArray): ByteArray {
|
||||
// Trim sentKeys if it grows too large
|
||||
@@ -512,32 +512,46 @@ class MlsGroup private constructor(
|
||||
|
||||
val kng = secretTree.nextApplicationKeyNonce(myLeafIndex)
|
||||
sentKeys[kng.generation] = kng
|
||||
val ciphertext = MlsCryptoProvider.aeadEncrypt(kng.key, kng.nonce, ByteArray(0), plaintext)
|
||||
|
||||
// Encrypt sender data
|
||||
// Generate 4-byte reuse_guard and XOR into the first 4 nonce bytes (RFC 9420 §6.3.1)
|
||||
val reuseGuard = MlsCryptoProvider.randomBytes(REUSE_GUARD_LENGTH)
|
||||
val guardedNonce = kng.nonce.copyOf()
|
||||
for (i in 0 until REUSE_GUARD_LENGTH) {
|
||||
guardedNonce[i] = (guardedNonce[i].toInt() xor reuseGuard[i].toInt()).toByte()
|
||||
}
|
||||
|
||||
// Build PrivateContentAAD (RFC 9420 §6.3.2)
|
||||
val contentAad = buildPrivateContentAAD(groupId, epoch, ContentType.APPLICATION, ByteArray(0))
|
||||
val ciphertext = MlsCryptoProvider.aeadEncrypt(kng.key, guardedNonce, contentAad, plaintext)
|
||||
|
||||
// Build sender data plaintext: leaf_index || generation || reuse_guard
|
||||
val senderDataWriter = TlsWriter()
|
||||
senderDataWriter.putUint32(myLeafIndex.toLong())
|
||||
senderDataWriter.putUint32(kng.generation.toLong())
|
||||
senderDataWriter.putBytes(reuseGuard)
|
||||
val senderDataPlain = senderDataWriter.toByteArray()
|
||||
|
||||
// Derive sender data key/nonce using ciphertext sample (RFC 9420 §6.3.1)
|
||||
val ciphertextSample = ciphertext.copyOfRange(0, minOf(ciphertext.size, MlsCryptoProvider.AEAD_KEY_LENGTH))
|
||||
val senderDataKey =
|
||||
MlsCryptoProvider.expandWithLabel(
|
||||
epochSecrets.senderDataSecret,
|
||||
"key",
|
||||
ByteArray(0),
|
||||
ciphertextSample,
|
||||
MlsCryptoProvider.AEAD_KEY_LENGTH,
|
||||
)
|
||||
val senderDataNonce =
|
||||
MlsCryptoProvider.expandWithLabel(
|
||||
epochSecrets.senderDataSecret,
|
||||
"nonce",
|
||||
ByteArray(0),
|
||||
ciphertextSample,
|
||||
MlsCryptoProvider.AEAD_NONCE_LENGTH,
|
||||
)
|
||||
|
||||
val senderDataWriter =
|
||||
com.vitorpamplona.quartz.marmot.mls.codec
|
||||
.TlsWriter()
|
||||
senderDataWriter.putUint32(myLeafIndex.toLong())
|
||||
senderDataWriter.putUint32(kng.generation.toLong())
|
||||
val senderDataPlain = senderDataWriter.toByteArray()
|
||||
// Build SenderDataAAD (RFC 9420 §6.3.1)
|
||||
val senderDataAad = buildSenderDataAAD(groupId, epoch, ContentType.APPLICATION)
|
||||
val encryptedSenderData =
|
||||
MlsCryptoProvider.aeadEncrypt(senderDataKey, senderDataNonce, ByteArray(0), senderDataPlain)
|
||||
MlsCryptoProvider.aeadEncrypt(senderDataKey, senderDataNonce, senderDataAad, senderDataPlain)
|
||||
|
||||
val msg =
|
||||
PrivateMessage(
|
||||
@@ -564,7 +578,7 @@ class MlsGroup private constructor(
|
||||
}
|
||||
|
||||
/**
|
||||
* Decrypt an application message from a PrivateMessage.
|
||||
* Decrypt an application message from a PrivateMessage (RFC 9420 Section 6.3).
|
||||
* @throws IllegalArgumentException if the message format is invalid
|
||||
* @throws javax.crypto.AEADBadTagException if decryption fails
|
||||
*/
|
||||
@@ -582,26 +596,37 @@ class MlsGroup private constructor(
|
||||
"Message group ID doesn't match current group"
|
||||
}
|
||||
|
||||
// Decrypt sender data
|
||||
// Derive sender data key/nonce using ciphertext sample (RFC 9420 §6.3.1)
|
||||
val ciphertextSample =
|
||||
privMsg.ciphertext.copyOfRange(0, minOf(privMsg.ciphertext.size, MlsCryptoProvider.AEAD_KEY_LENGTH))
|
||||
val senderDataKey =
|
||||
MlsCryptoProvider.expandWithLabel(
|
||||
epochSecrets.senderDataSecret,
|
||||
"key",
|
||||
ByteArray(0),
|
||||
ciphertextSample,
|
||||
MlsCryptoProvider.AEAD_KEY_LENGTH,
|
||||
)
|
||||
val senderDataNonce =
|
||||
MlsCryptoProvider.expandWithLabel(
|
||||
epochSecrets.senderDataSecret,
|
||||
"nonce",
|
||||
ByteArray(0),
|
||||
ciphertextSample,
|
||||
MlsCryptoProvider.AEAD_NONCE_LENGTH,
|
||||
)
|
||||
|
||||
// Build SenderDataAAD and decrypt sender data (RFC 9420 §6.3.1)
|
||||
val senderDataAad = buildSenderDataAAD(privMsg.groupId, privMsg.epoch, privMsg.contentType)
|
||||
val senderDataPlain =
|
||||
MlsCryptoProvider.aeadDecrypt(senderDataKey, senderDataNonce, ByteArray(0), privMsg.encryptedSenderData)
|
||||
MlsCryptoProvider.aeadDecrypt(senderDataKey, senderDataNonce, senderDataAad, privMsg.encryptedSenderData)
|
||||
val senderReader = TlsReader(senderDataPlain)
|
||||
val senderLeafIndex = senderReader.readUint32().toInt()
|
||||
val generation = senderReader.readUint32().toInt()
|
||||
val reuseGuard = senderReader.readBytes(REUSE_GUARD_LENGTH)
|
||||
|
||||
// Validate sender leaf index (M12)
|
||||
require(senderLeafIndex in 0 until tree.leafCount) {
|
||||
"Sender leaf index $senderLeafIndex out of range [0, ${tree.leafCount})"
|
||||
}
|
||||
|
||||
// Get the key/nonce for this sender+generation
|
||||
// If we sent this message ourselves, use the cached key to avoid ratchet conflict
|
||||
@@ -612,8 +637,15 @@ class MlsGroup private constructor(
|
||||
secretTree.applicationKeyNonceForGeneration(senderLeafIndex, generation)
|
||||
}
|
||||
|
||||
// Decrypt content
|
||||
val plaintext = MlsCryptoProvider.aeadDecrypt(kng.key, kng.nonce, ByteArray(0), privMsg.ciphertext)
|
||||
// Apply reuse_guard XOR to nonce (RFC 9420 §6.3.1)
|
||||
val guardedNonce = kng.nonce.copyOf()
|
||||
for (i in 0 until REUSE_GUARD_LENGTH) {
|
||||
guardedNonce[i] = (guardedNonce[i].toInt() xor reuseGuard[i].toInt()).toByte()
|
||||
}
|
||||
|
||||
// Decrypt content with PrivateContentAAD (RFC 9420 §6.3.2)
|
||||
val contentAad = buildPrivateContentAAD(privMsg.groupId, privMsg.epoch, privMsg.contentType, privMsg.authenticatedData)
|
||||
val plaintext = MlsCryptoProvider.aeadDecrypt(kng.key, guardedNonce, contentAad, privMsg.ciphertext)
|
||||
|
||||
return DecryptedMessage(
|
||||
senderLeafIndex = senderLeafIndex,
|
||||
@@ -635,7 +667,7 @@ class MlsGroup private constructor(
|
||||
fun processCommit(
|
||||
commitBytes: ByteArray,
|
||||
senderLeafIndex: Int,
|
||||
confirmationTag: ByteArray? = null,
|
||||
confirmationTag: ByteArray,
|
||||
) {
|
||||
val commit = Commit.decodeTls(TlsReader(commitBytes))
|
||||
|
||||
@@ -667,7 +699,7 @@ class MlsGroup private constructor(
|
||||
}
|
||||
|
||||
is ProposalOrRef.Reference -> {
|
||||
// Resolve proposal by reference hash from pending proposals
|
||||
// Resolve proposal by reference hash from pending proposals (RFC 9420 §12.4.2)
|
||||
val refHash = proposalOrRef.proposalRef
|
||||
val resolved =
|
||||
pendingProposals.find { pending ->
|
||||
@@ -675,9 +707,10 @@ class MlsGroup private constructor(
|
||||
val hash = MlsCryptoProvider.refHash("MLS 1.0 Proposal Reference", proposalBytes)
|
||||
hash.contentEquals(refHash)
|
||||
}
|
||||
if (resolved != null) {
|
||||
applyProposal(resolved.proposal, resolved.senderLeafIndex)
|
||||
requireNotNull(resolved) {
|
||||
"Commit references unknown proposal (ref not found in pending proposals)"
|
||||
}
|
||||
applyProposal(resolved.proposal, resolved.senderLeafIndex)
|
||||
}
|
||||
}
|
||||
}
|
||||
@@ -690,11 +723,15 @@ class MlsGroup private constructor(
|
||||
require(verifyLeafNodeSignature(updatePath.leafNode, groupId, senderLeafIndex)) {
|
||||
"Invalid LeafNode signature in UpdatePath"
|
||||
}
|
||||
|
||||
// Capture sibling tree hashes BEFORE applying UpdatePath (needed for parent hash verification)
|
||||
val preUpdateSiblingHashes = capturePreUpdateSiblingHashes(senderLeafIndex)
|
||||
|
||||
tree.setLeaf(senderLeafIndex, updatePath.leafNode)
|
||||
tree.applyUpdatePath(senderLeafIndex, updatePath.nodes)
|
||||
|
||||
// Verify parent hash chain (RFC 9420 Section 7.9.2)
|
||||
require(verifyParentHash(senderLeafIndex, updatePath)) {
|
||||
// Verify parent hash chain (RFC 9420 Section 7.9.2) using pre-update sibling hashes
|
||||
require(verifyParentHash(senderLeafIndex, updatePath, preUpdateSiblingHashes)) {
|
||||
"Parent hash verification failed for UpdatePath"
|
||||
}
|
||||
|
||||
@@ -724,10 +761,12 @@ class MlsGroup private constructor(
|
||||
ct.ciphertext,
|
||||
)
|
||||
|
||||
// Derive remaining path secrets up to root
|
||||
val remainingPath = directPath.drop(commonAncestorIdx)
|
||||
// Derive remaining path secrets from common ancestor up to root.
|
||||
// pathSecret is the secret AT commonAncestorIdx, so we derive
|
||||
// (directPath.size - commonAncestorIdx - 1) more steps to reach root.
|
||||
val remainingSteps = directPath.size - commonAncestorIdx - 1
|
||||
var currentSecret = pathSecret
|
||||
for (nodeIdx in remainingPath) {
|
||||
repeat(remainingSteps) {
|
||||
currentSecret = MlsCryptoProvider.deriveSecret(currentSecret, "path")
|
||||
}
|
||||
commitSecret = currentSecret
|
||||
@@ -780,12 +819,10 @@ class MlsGroup private constructor(
|
||||
initSecret = epochSecrets.initSecret
|
||||
secretTree = SecretTree(epochSecrets.encryptionSecret, tree.leafCount)
|
||||
|
||||
// Verify confirmation tag (RFC 9420 Section 6.1)
|
||||
if (confirmationTag != null) {
|
||||
val expectedTag = computeConfirmationTag(epochSecrets.confirmationKey, newConfirmedTranscriptHash)
|
||||
require(constantTimeEquals(confirmationTag, expectedTag)) {
|
||||
"Confirmation tag verification failed"
|
||||
}
|
||||
// Verify confirmation tag (RFC 9420 Section 6.1) — mandatory for all commits
|
||||
val expectedTag = computeConfirmationTag(epochSecrets.confirmationKey, newConfirmedTranscriptHash)
|
||||
require(constantTimeEquals(confirmationTag, expectedTag)) {
|
||||
"Confirmation tag verification failed"
|
||||
}
|
||||
|
||||
// Update interim_transcript_hash for next epoch
|
||||
@@ -918,31 +955,23 @@ class MlsGroup private constructor(
|
||||
private fun buildConfirmedTranscriptHashInput(
|
||||
commit: Commit,
|
||||
senderLeafIndex: Int,
|
||||
): ByteArray {
|
||||
val writer = TlsWriter()
|
||||
// wire_format: PublicMessage = 1
|
||||
writer.putUint16(WireFormat.PUBLIC_MESSAGE.value)
|
||||
// FramedContent: group_id, epoch, sender, authenticated_data, content_type, content
|
||||
writer.putOpaqueVarInt(groupId)
|
||||
writer.putUint64(epoch)
|
||||
// Sender: member type (1) + leaf_index
|
||||
writer.putUint8(1) // SenderType.MEMBER
|
||||
writer.putUint32(senderLeafIndex.toLong())
|
||||
writer.putOpaqueVarInt(ByteArray(0)) // authenticated_data (empty)
|
||||
writer.putUint8(ContentType.COMMIT.value) // content_type
|
||||
commit.encodeTls(writer) // content = Commit
|
||||
// signature (placeholder — in a full implementation this would be the actual signature)
|
||||
writer.putOpaqueVarInt(ByteArray(0))
|
||||
return writer.toByteArray()
|
||||
}
|
||||
): ByteArray = buildConfirmedTranscriptHashInput(commit, senderLeafIndex, groupId, epoch)
|
||||
|
||||
private fun computeConfirmationTag(
|
||||
confirmationKey: ByteArray,
|
||||
confirmedTranscriptHash: ByteArray,
|
||||
): ByteArray {
|
||||
val mac = MacInstance("HmacSHA256", confirmationKey)
|
||||
mac.update(confirmedTranscriptHash)
|
||||
return mac.doFinal()
|
||||
/**
|
||||
* Capture sibling tree hashes BEFORE the UpdatePath is applied.
|
||||
* Returns a map of direct-path-index to sibling tree hash.
|
||||
*/
|
||||
private fun capturePreUpdateSiblingHashes(senderLeafIndex: Int): Map<Int, ByteArray> {
|
||||
val directPath = BinaryTree.directPath(senderLeafIndex, tree.leafCount)
|
||||
val nodeCount = BinaryTree.nodeCount(tree.leafCount)
|
||||
val result = mutableMapOf<Int, ByteArray>()
|
||||
for ((i, _) in directPath.withIndex()) {
|
||||
val childIdx =
|
||||
if (i == 0) BinaryTree.leafToNode(senderLeafIndex) else directPath[i - 1]
|
||||
val siblingIdx = BinaryTree.sibling(childIdx, nodeCount)
|
||||
result[i] = tree.treeHashNode(siblingIdx)
|
||||
}
|
||||
return result
|
||||
}
|
||||
|
||||
/**
|
||||
@@ -956,10 +985,13 @@ class MlsGroup private constructor(
|
||||
* opaque parent_hash<V>; // parent's own parent_hash
|
||||
* opaque original_sibling_tree_hash<V>; // tree hash of the sibling subtree
|
||||
* }
|
||||
*
|
||||
* @param preUpdateSiblingHashes sibling hashes captured BEFORE the UpdatePath was applied
|
||||
*/
|
||||
private fun verifyParentHash(
|
||||
senderLeafIndex: Int,
|
||||
updatePath: UpdatePath,
|
||||
preUpdateSiblingHashes: Map<Int, ByteArray>,
|
||||
): Boolean {
|
||||
val directPath = BinaryTree.directPath(senderLeafIndex, tree.leafCount)
|
||||
if (directPath.isEmpty()) return true
|
||||
@@ -967,22 +999,14 @@ class MlsGroup private constructor(
|
||||
val leafParentHash = updatePath.leafNode.parentHash ?: return true
|
||||
if (leafParentHash.isEmpty()) return true
|
||||
|
||||
val nodeCount = BinaryTree.nodeCount(tree.leafCount)
|
||||
|
||||
// Walk up the direct path, verifying each parent_hash link
|
||||
var expectedParentHash = leafParentHash
|
||||
for ((i, pathNodeIdx) in directPath.withIndex()) {
|
||||
val pathNode = tree.getNode(pathNodeIdx) ?: continue
|
||||
|
||||
if (pathNode is com.vitorpamplona.quartz.marmot.mls.tree.TreeNode.Parent) {
|
||||
// Compute the parent hash for this node
|
||||
val childIdx =
|
||||
if (i == 0) BinaryTree.leafToNode(senderLeafIndex) else directPath[i - 1]
|
||||
val siblingIdx = BinaryTree.sibling(childIdx, nodeCount)
|
||||
|
||||
// original_sibling_tree_hash = tree hash of the sibling subtree
|
||||
// (computed BEFORE the UpdatePath was applied)
|
||||
val siblingHash = tree.treeHashNode(siblingIdx)
|
||||
// Use the pre-update sibling tree hash (captured before UpdatePath was applied)
|
||||
val siblingHash = preUpdateSiblingHashes[i] ?: continue
|
||||
|
||||
// ParentHashInput
|
||||
val phi = TlsWriter()
|
||||
@@ -1038,6 +1062,53 @@ class MlsGroup private constructor(
|
||||
return constantTimeEquals(expectedTag, membershipTag)
|
||||
}
|
||||
|
||||
/**
|
||||
* Build PrivateContentAAD (RFC 9420 §6.3.2):
|
||||
* ```
|
||||
* struct {
|
||||
* opaque group_id<V>;
|
||||
* uint64 epoch;
|
||||
* ContentType content_type;
|
||||
* opaque authenticated_data<V>;
|
||||
* } PrivateContentAAD;
|
||||
* ```
|
||||
*/
|
||||
private fun buildPrivateContentAAD(
|
||||
groupId: ByteArray,
|
||||
epoch: Long,
|
||||
contentType: ContentType,
|
||||
authenticatedData: ByteArray,
|
||||
): ByteArray {
|
||||
val writer = TlsWriter()
|
||||
writer.putOpaqueVarInt(groupId)
|
||||
writer.putUint64(epoch)
|
||||
writer.putUint8(contentType.value)
|
||||
writer.putOpaqueVarInt(authenticatedData)
|
||||
return writer.toByteArray()
|
||||
}
|
||||
|
||||
/**
|
||||
* Build SenderDataAAD (RFC 9420 §6.3.1):
|
||||
* ```
|
||||
* struct {
|
||||
* opaque group_id<V>;
|
||||
* uint64 epoch;
|
||||
* ContentType content_type;
|
||||
* } SenderDataAAD;
|
||||
* ```
|
||||
*/
|
||||
private fun buildSenderDataAAD(
|
||||
groupId: ByteArray,
|
||||
epoch: Long,
|
||||
contentType: ContentType,
|
||||
): ByteArray {
|
||||
val writer = TlsWriter()
|
||||
writer.putOpaqueVarInt(groupId)
|
||||
writer.putUint64(epoch)
|
||||
writer.putUint8(contentType.value)
|
||||
return writer.toByteArray()
|
||||
}
|
||||
|
||||
/**
|
||||
* Constant-time byte array comparison to prevent timing side-channels.
|
||||
* Returns true only if both arrays have the same length and contents.
|
||||
@@ -1149,11 +1220,9 @@ class MlsGroup private constructor(
|
||||
groupContext = groupContext,
|
||||
extensions = listOf(ratchetTreeExtension),
|
||||
confirmationTag =
|
||||
MlsCryptoProvider.expandWithLabel(
|
||||
computeConfirmationTag(
|
||||
epochSecrets.confirmationKey,
|
||||
"confirmation",
|
||||
groupContext.confirmedTranscriptHash,
|
||||
MlsCryptoProvider.HASH_OUTPUT_LENGTH,
|
||||
),
|
||||
signer = myLeafIndex,
|
||||
signature = ByteArray(0),
|
||||
@@ -1223,7 +1292,45 @@ class MlsGroup private constructor(
|
||||
|
||||
companion object {
|
||||
private const val MAX_SENT_KEYS = 10_000
|
||||
private const val REUSE_GUARD_LENGTH = 4
|
||||
private const val RATCHET_TREE_EXTENSION_TYPE = 0x0001
|
||||
|
||||
/**
|
||||
* Build ConfirmedTranscriptHashInput (RFC 9420 Section 8.2) — static version
|
||||
* usable from both instance methods and companion object factory methods.
|
||||
*/
|
||||
private fun buildConfirmedTranscriptHashInput(
|
||||
commit: Commit,
|
||||
senderLeafIndex: Int,
|
||||
groupId: ByteArray,
|
||||
epoch: Long,
|
||||
): ByteArray {
|
||||
val writer = TlsWriter()
|
||||
writer.putUint16(WireFormat.PUBLIC_MESSAGE.value)
|
||||
writer.putOpaqueVarInt(groupId)
|
||||
writer.putUint64(epoch)
|
||||
writer.putUint8(1) // SenderType.MEMBER
|
||||
writer.putUint32(senderLeafIndex.toLong())
|
||||
writer.putOpaqueVarInt(ByteArray(0)) // authenticated_data
|
||||
writer.putUint8(ContentType.COMMIT.value)
|
||||
commit.encodeTls(writer)
|
||||
writer.putOpaqueVarInt(ByteArray(0)) // signature placeholder
|
||||
return writer.toByteArray()
|
||||
}
|
||||
|
||||
/**
|
||||
* Compute confirmation_tag = MAC(confirmation_key, confirmed_transcript_hash).
|
||||
* Static version usable from companion object factory methods.
|
||||
*/
|
||||
private fun computeConfirmationTag(
|
||||
confirmationKey: ByteArray,
|
||||
confirmedTranscriptHash: ByteArray,
|
||||
): ByteArray {
|
||||
val mac = MacInstance("HmacSHA256", confirmationKey)
|
||||
mac.update(confirmedTranscriptHash)
|
||||
return mac.doFinal()
|
||||
}
|
||||
|
||||
private const val REQUIRED_CAPABILITIES_EXTENSION_TYPE = 0x0002
|
||||
private const val EXTERNAL_PUB_EXTENSION_TYPE = 0x0003
|
||||
private const val EXTERNAL_SENDERS_EXTENSION_TYPE = 0x0004
|
||||
@@ -1568,12 +1675,21 @@ class MlsGroup private constructor(
|
||||
ByteArray(MlsCryptoProvider.HASH_OUTPUT_LENGTH)
|
||||
}
|
||||
|
||||
// Update transcript hashes for external join commit
|
||||
val confirmedTranscriptHashInput =
|
||||
buildConfirmedTranscriptHashInput(commit, myLeafIndex, groupContext.groupId, groupContext.epoch)
|
||||
val confirmedInput = TlsWriter()
|
||||
confirmedInput.putBytes(ByteArray(0)) // initial interim transcript hash
|
||||
confirmedInput.putBytes(confirmedTranscriptHashInput)
|
||||
val newConfirmedTranscriptHash = MlsCryptoProvider.hash(confirmedInput.toByteArray())
|
||||
|
||||
val newTreeHash = tree.treeHash()
|
||||
val newEpoch = groupContext.epoch + 1
|
||||
val newGroupContext =
|
||||
groupContext.copy(
|
||||
epoch = newEpoch,
|
||||
treeHash = newTreeHash,
|
||||
confirmedTranscriptHash = newConfirmedTranscriptHash,
|
||||
)
|
||||
|
||||
val keySchedule = KeySchedule(newGroupContext.toTlsBytes())
|
||||
@@ -1581,6 +1697,13 @@ class MlsGroup private constructor(
|
||||
|
||||
val secretTree = SecretTree(epochSecrets.encryptionSecret, tree.leafCount)
|
||||
|
||||
// Compute interim transcript hash
|
||||
val confirmationTag = computeConfirmationTag(epochSecrets.confirmationKey, newConfirmedTranscriptHash)
|
||||
val interimInput = TlsWriter()
|
||||
interimInput.putBytes(newConfirmedTranscriptHash)
|
||||
interimInput.putOpaqueVarInt(confirmationTag)
|
||||
val interimTranscriptHash = MlsCryptoProvider.hash(interimInput.toByteArray())
|
||||
|
||||
val group =
|
||||
MlsGroup(
|
||||
groupContext = newGroupContext,
|
||||
@@ -1591,7 +1714,7 @@ class MlsGroup private constructor(
|
||||
initSecret = epochSecrets.initSecret,
|
||||
signingPrivateKey = sigKp.privateKey,
|
||||
encryptionPrivateKey = encKp.privateKey,
|
||||
interimTranscriptHash = ByteArray(0),
|
||||
interimTranscriptHash = interimTranscriptHash,
|
||||
)
|
||||
|
||||
return Pair(group, commitBytes)
|
||||
|
||||
+42
-10
@@ -257,7 +257,7 @@ class MlsGroupManager(
|
||||
nostrGroupId: HexKey,
|
||||
commitBytes: ByteArray,
|
||||
senderLeafIndex: Int,
|
||||
confirmationTag: ByteArray? = null,
|
||||
confirmationTag: ByteArray,
|
||||
) = mutex.withLock {
|
||||
val group = requireGroup(nostrGroupId)
|
||||
|
||||
@@ -272,19 +272,24 @@ class MlsGroupManager(
|
||||
|
||||
/**
|
||||
* Encrypt an application message.
|
||||
* Synchronized to prevent nonce reuse from concurrent encryption.
|
||||
*/
|
||||
fun encrypt(
|
||||
suspend fun encrypt(
|
||||
nostrGroupId: HexKey,
|
||||
plaintext: ByteArray,
|
||||
): ByteArray = requireGroup(nostrGroupId).encrypt(plaintext)
|
||||
): ByteArray =
|
||||
mutex.withLock {
|
||||
requireGroup(nostrGroupId).encrypt(plaintext)
|
||||
}
|
||||
|
||||
/**
|
||||
* Decrypt an application message.
|
||||
*
|
||||
* Tries the current epoch first, then falls back to retained epoch
|
||||
* secrets for late-arriving messages from previous epochs.
|
||||
* Synchronized to prevent concurrent state corruption.
|
||||
*/
|
||||
fun decrypt(
|
||||
suspend fun decrypt(
|
||||
nostrGroupId: HexKey,
|
||||
messageBytes: ByteArray,
|
||||
): DecryptedMessage {
|
||||
@@ -308,7 +313,7 @@ class MlsGroupManager(
|
||||
/**
|
||||
* Decrypt with null return on failure.
|
||||
*/
|
||||
fun decryptOrNull(
|
||||
suspend fun decryptOrNull(
|
||||
nostrGroupId: HexKey,
|
||||
messageBytes: ByteArray,
|
||||
): DecryptedMessage? =
|
||||
@@ -510,35 +515,59 @@ class MlsGroupManager(
|
||||
.decodeTls(TlsReader(mlsMsg.payload))
|
||||
if (privMsg.epoch != retained.epoch) return null
|
||||
|
||||
// Decrypt sender data
|
||||
// Derive sender data key/nonce using ciphertext sample (RFC 9420 §6.3.1)
|
||||
val ciphertextSample =
|
||||
privMsg.ciphertext.copyOfRange(0, minOf(privMsg.ciphertext.size, MlsCryptoProvider.AEAD_KEY_LENGTH))
|
||||
val senderDataKey =
|
||||
MlsCryptoProvider.expandWithLabel(
|
||||
retained.senderDataSecret,
|
||||
"key",
|
||||
ByteArray(0),
|
||||
ciphertextSample,
|
||||
MlsCryptoProvider.AEAD_KEY_LENGTH,
|
||||
)
|
||||
val senderDataNonce =
|
||||
MlsCryptoProvider.expandWithLabel(
|
||||
retained.senderDataSecret,
|
||||
"nonce",
|
||||
ByteArray(0),
|
||||
ciphertextSample,
|
||||
MlsCryptoProvider.AEAD_NONCE_LENGTH,
|
||||
)
|
||||
|
||||
// Build SenderDataAAD
|
||||
val senderDataAad = TlsWriter()
|
||||
senderDataAad.putOpaqueVarInt(privMsg.groupId)
|
||||
senderDataAad.putUint64(privMsg.epoch)
|
||||
senderDataAad.putUint8(privMsg.contentType.value)
|
||||
|
||||
val senderDataPlain =
|
||||
MlsCryptoProvider.aeadDecrypt(
|
||||
senderDataKey,
|
||||
senderDataNonce,
|
||||
ByteArray(0),
|
||||
senderDataAad.toByteArray(),
|
||||
privMsg.encryptedSenderData,
|
||||
)
|
||||
val senderReader = TlsReader(senderDataPlain)
|
||||
val senderLeafIndex = senderReader.readUint32().toInt()
|
||||
val generation = senderReader.readUint32().toInt()
|
||||
val reuseGuard = senderReader.readBytes(REUSE_GUARD_LENGTH)
|
||||
|
||||
val kng = secretTree.applicationKeyNonceForGeneration(senderLeafIndex, generation)
|
||||
|
||||
// Apply reuse_guard XOR to nonce
|
||||
val guardedNonce = kng.nonce.copyOf()
|
||||
for (i in 0 until REUSE_GUARD_LENGTH) {
|
||||
guardedNonce[i] = (guardedNonce[i].toInt() xor reuseGuard[i].toInt()).toByte()
|
||||
}
|
||||
|
||||
// Build PrivateContentAAD
|
||||
val contentAad = TlsWriter()
|
||||
contentAad.putOpaqueVarInt(privMsg.groupId)
|
||||
contentAad.putUint64(privMsg.epoch)
|
||||
contentAad.putUint8(privMsg.contentType.value)
|
||||
contentAad.putOpaqueVarInt(privMsg.authenticatedData)
|
||||
|
||||
val plaintext =
|
||||
MlsCryptoProvider.aeadDecrypt(kng.key, kng.nonce, ByteArray(0), privMsg.ciphertext)
|
||||
MlsCryptoProvider.aeadDecrypt(kng.key, guardedNonce, contentAad.toByteArray(), privMsg.ciphertext)
|
||||
|
||||
DecryptedMessage(
|
||||
senderLeafIndex = senderLeafIndex,
|
||||
@@ -556,5 +585,8 @@ class MlsGroupManager(
|
||||
* MLS forward secrecy guarantees mean we want to limit this window.
|
||||
*/
|
||||
const val EPOCH_RETENTION_WINDOW = 2
|
||||
|
||||
/** Size of reuse_guard in PrivateMessage (RFC 9420 §6.3.1) */
|
||||
private const val REUSE_GUARD_LENGTH = 4
|
||||
}
|
||||
}
|
||||
|
||||
+3
-1
@@ -122,7 +122,9 @@ data class MlsKeyPackage(
|
||||
val version = reader.readUint16()
|
||||
require(version == 1) { "Unsupported MLS version: $version" }
|
||||
val cipherSuite = reader.readUint16()
|
||||
require(cipherSuite in 1..0xFFFF) { "Invalid ciphersuite: $cipherSuite" }
|
||||
require(cipherSuite == 1) {
|
||||
"Unsupported ciphersuite: $cipherSuite (only MLS_128_DHKEMX25519_AES128GCM_SHA256_Ed25519 = 0x0001 is supported)"
|
||||
}
|
||||
return MlsKeyPackage(
|
||||
version = version,
|
||||
cipherSuite = cipherSuite,
|
||||
|
||||
+2
-2
@@ -45,8 +45,8 @@ enum class ProposalType(
|
||||
EXTERNAL_INIT(6),
|
||||
GROUP_CONTEXT_EXTENSIONS(7),
|
||||
|
||||
// Marmot custom proposal types
|
||||
SELF_REMOVE(0x0008),
|
||||
// Marmot custom proposal types (private-use range 0xF000-0xFFFF)
|
||||
SELF_REMOVE(0xF001),
|
||||
;
|
||||
|
||||
companion object {
|
||||
|
||||
Reference in New Issue
Block a user