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Merged
t-bast merged 2 commits into from
Jul 17, 2026
+79 −57
Merged

Reject temporary_channel_id duplicates early #3324

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a5746f9
Reject `temporary_channel_id` duplicates early
t-bast Jul 7, 2026
17c33cb
Reject duplicates after rate-limiting
t-bast Jul 16, 2026
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119 changes: 62 additions & 57 deletions eclair-core/src/main/scala/fr/acinq/eclair/io/Peer.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -239,7 +239,7 @@ class Peer(val nodeParams: NodeParams,
stay() using d.copy(channels = d.channels + (TemporaryChannelId(temporaryChannelId) -> channel))

case Event(open: protocol.OpenChannel, d: ConnectedData) =>
d.channels.get(TemporaryChannelId(open.temporaryChannelId)) match {
d.channels.get(TemporaryChannelId(open.temporaryChannelId)).orElse(d.channels.get(FinalChannelId(open.temporaryChannelId))) match {
case None =>
openChannelInterceptor ! OpenChannelNonInitiator(remoteNodeId, Left(open), d.localFeatures, d.remoteFeatures, d.peerConnection.toTyped, d.address)
stay()
Expand All @@ -249,7 +249,7 @@ class Peer(val nodeParams: NodeParams,
}

case Event(open: protocol.OpenDualFundedChannel, d: ConnectedData) =>
d.channels.get(TemporaryChannelId(open.temporaryChannelId)) match {
d.channels.get(TemporaryChannelId(open.temporaryChannelId)).orElse(d.channels.get(FinalChannelId(open.temporaryChannelId))) match {
case None if !Features.canUseFeature(d.localFeatures, d.remoteFeatures, Features.DualFunding) =>
log.info("rejecting open_channel2: dual funding is not supported")
self ! Peer.OutgoingMessage(Error(open.temporaryChannelId, "dual funding is not supported"), d.peerConnection)
Expand All @@ -268,61 +268,66 @@ class Peer(val nodeParams: NodeParams,

case Event(SpawnChannelNonInitiator(open, channelConfig, channelType, addFunding_opt, localParams, peerConnection), d: ConnectedData) =>
val temporaryChannelId = open.fold(_.temporaryChannelId, _.temporaryChannelId)
if (peerConnection == d.peerConnection) {
OnTheFlyFunding.validateOpen(nodeParams.onTheFlyFundingConfig, remoteNodeId, open, pendingOnTheFlyFunding, feeCredit.getOrElse(0 msat)) match {
case reject: OnTheFlyFunding.ValidationResult.Reject =>
log.warning("rejecting on-the-fly channel: {}", reject.cancel.toAscii)
self ! Peer.OutgoingMessage(reject.cancel, d.peerConnection)
cancelUnsignedOnTheFlyFunding(reject.paymentHashes)
context.system.eventStream.publish(ChannelAborted(ActorRef.noSender, remoteNodeId, temporaryChannelId))
stay()
case accept: OnTheFlyFunding.ValidationResult.Accept =>
val channelKeys = nodeParams.channelKeyManager.channelKeys(channelConfig, localParams.fundingKeyPath)
val channel = spawnChannel(channelKeys)
context.system.scheduler.scheduleOnce(nodeParams.channelConf.channelFundingTimeout, channel, Channel.TickChannelOpenTimeout)(context.dispatcher)
log.info(s"accepting a new channel with type=$channelType temporaryChannelId=$temporaryChannelId localParams=$localParams")
open match {
case Left(open) =>
val init = INPUT_INIT_CHANNEL_NON_INITIATOR(
temporaryChannelId = open.temporaryChannelId,
fundingContribution_opt = None,
dualFunded = false,
pushAmount_opt = None,
requireConfirmedInputs = false,
localChannelParams = localParams,
proposedCommitParams = nodeParams.channelConf.commitParams(open.fundingSatoshis, channelType, unlimitedMaxHtlcValueInFlight = false),
remote = d.peerConnection,
remoteInit = d.remoteInit,
channelConfig = channelConfig,
channelType = channelType)
channel ! init
channel ! open
case Right(open) =>
val init = INPUT_INIT_CHANNEL_NON_INITIATOR(
temporaryChannelId = open.temporaryChannelId,
fundingContribution_opt = addFunding_opt,
dualFunded = true,
pushAmount_opt = None,
requireConfirmedInputs = nodeParams.channelConf.requireConfirmedInputsForDualFunding,
localChannelParams = localParams,
proposedCommitParams = nodeParams.channelConf.commitParams(open.fundingAmount + addFunding_opt.map(_.fundingAmount).getOrElse(0 sat), channelType, unlimitedMaxHtlcValueInFlight = false),
remote = d.peerConnection,
remoteInit = d.remoteInit,
channelConfig = channelConfig,
channelType = channelType)
channel ! init
accept.useFeeCredit_opt match {
case Some(useFeeCredit) => channel ! open.copy(tlvStream = TlvStream(open.tlvStream.records + ChannelTlv.UseFeeCredit(useFeeCredit)))
case None => channel ! open
}
}
fulfillOnTheFlyFundingHtlcs(accept.preimages)
stay() using d.copy(channels = d.channels + (TemporaryChannelId(temporaryChannelId) -> channel))
}
} else {
log.warning("ignoring open_channel request that reconnected during channel intercept, temporaryChannelId={}", temporaryChannelId)
context.system.eventStream.publish(ChannelAborted(ActorRef.noSender, remoteNodeId, temporaryChannelId))
stay()
// Since the channel interceptor step isn't atomic, we must check again that there is no duplicate/conflict.
d.channels.get(TemporaryChannelId(temporaryChannelId)).orElse(d.channels.get(FinalChannelId(temporaryChannelId))) match {
case Some(_) =>
log.warning("ignoring open_channel with duplicate temporaryChannelId={}", temporaryChannelId)
stay()
case None if peerConnection != d.peerConnection =>
log.warning("ignoring open_channel request that reconnected during channel intercept, temporaryChannelId={}", temporaryChannelId)
context.system.eventStream.publish(ChannelAborted(ActorRef.noSender, remoteNodeId, temporaryChannelId))
stay()
case None =>
OnTheFlyFunding.validateOpen(nodeParams.onTheFlyFundingConfig, remoteNodeId, open, pendingOnTheFlyFunding, feeCredit.getOrElse(0 msat)) match {
case reject: OnTheFlyFunding.ValidationResult.Reject =>
log.warning("rejecting on-the-fly channel: {}", reject.cancel.toAscii)
self ! Peer.OutgoingMessage(reject.cancel, d.peerConnection)
cancelUnsignedOnTheFlyFunding(reject.paymentHashes)
context.system.eventStream.publish(ChannelAborted(ActorRef.noSender, remoteNodeId, temporaryChannelId))
stay()
case accept: OnTheFlyFunding.ValidationResult.Accept =>
val channelKeys = nodeParams.channelKeyManager.channelKeys(channelConfig, localParams.fundingKeyPath)
val channel = spawnChannel(channelKeys)
context.system.scheduler.scheduleOnce(nodeParams.channelConf.channelFundingTimeout, channel, Channel.TickChannelOpenTimeout)(context.dispatcher)
log.info(s"accepting a new channel with type=$channelType temporaryChannelId=$temporaryChannelId localParams=$localParams")
open match {
case Left(open) =>
val init = INPUT_INIT_CHANNEL_NON_INITIATOR(
temporaryChannelId = open.temporaryChannelId,
fundingContribution_opt = None,
dualFunded = false,
pushAmount_opt = None,
requireConfirmedInputs = false,
localChannelParams = localParams,
proposedCommitParams = nodeParams.channelConf.commitParams(open.fundingSatoshis, channelType, unlimitedMaxHtlcValueInFlight = false),
remote = d.peerConnection,
remoteInit = d.remoteInit,
channelConfig = channelConfig,
channelType = channelType)
channel ! init
channel ! open
case Right(open) =>
val init = INPUT_INIT_CHANNEL_NON_INITIATOR(
temporaryChannelId = open.temporaryChannelId,
fundingContribution_opt = addFunding_opt,
dualFunded = true,
pushAmount_opt = None,
requireConfirmedInputs = nodeParams.channelConf.requireConfirmedInputsForDualFunding,
localChannelParams = localParams,
proposedCommitParams = nodeParams.channelConf.commitParams(open.fundingAmount + addFunding_opt.map(_.fundingAmount).getOrElse(0 sat), channelType, unlimitedMaxHtlcValueInFlight = false),
remote = d.peerConnection,
remoteInit = d.remoteInit,
channelConfig = channelConfig,
channelType = channelType)
channel ! init
accept.useFeeCredit_opt match {
case Some(useFeeCredit) => channel ! open.copy(tlvStream = TlvStream(open.tlvStream.records + ChannelTlv.UseFeeCredit(useFeeCredit)))
case None => channel ! open
}
}
fulfillOnTheFlyFundingHtlcs(accept.preimages)
stay() using d.copy(channels = d.channels + (TemporaryChannelId(temporaryChannelId) -> channel))
}
}

case Event(cmd: ProposeOnTheFlyFunding, d: ConnectedData) if !d.remoteFeatures.hasFeature(Features.OnTheFlyFunding) =>
Expand Down
17 changes: 17 additions & 0 deletions eclair-core/src/test/scala/fr/acinq/eclair/io/PeerSpec.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -448,6 +448,23 @@ class PeerSpec extends FixtureSpec {
assert(peer.stateData.channels.size == 1)
}

test("don't spawn a channel that reuses an existing channel id") { f =>
import f._

val confirmedChannel = ChannelCodecsSpec.normal.withChannelKeys(nodeParams)
connect(remoteNodeId, peer, peerConnection, switchboard, channels = Set(confirmedChannel))
channel.expectMsg(INPUT_RESTORED(confirmedChannel.channelData))
channel.expectMsgType[INPUT_RECONNECTED]

val open = createOpenChannelMessage(ChannelTypes.AnchorOutputsZeroFeeHtlcTx()).copy(temporaryChannelId = confirmedChannel.channelId)
peerConnection.send(peer, open)
val open2 = createOpenDualFundedChannelMessage(ChannelTypes.AnchorOutputsZeroFeeHtlcTx()).copy(temporaryChannelId = confirmedChannel.channelId)
peerConnection.send(peer, open2)
channel.expectNoMessage(100 millis)
peerConnection.expectNoMessage(100 millis)
assert(peer.stateData.channels.size == 1)
}

test("send error when receiving message for unknown channel") { f =>
import f._

Expand Down
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