From 7e255b5cf5256638b5ec6e507c68d9cfa0ba2047 Mon Sep 17 00:00:00 2001
From: Matt Corallo <git@bluematt.me>
Date: Sun, 29 Jul 2018 01:59:42 -0400
Subject: [PATCH] Handle invalid funding tx in channelmanager

---
 src/ln/channel.rs        | 14 +++++++++-----
 src/ln/channelmanager.rs | 13 ++++++++++++-
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/src/ln/channel.rs b/src/ln/channel.rs
index 3a442091c..acee06409 100644
--- a/src/ln/channel.rs
+++ b/src/ln/channel.rs
@@ -14,7 +14,7 @@ use crypto::digest::Digest;
 use crypto::hkdf::{hkdf_extract,hkdf_expand};
 
 use ln::msgs;
-use ln::msgs::{HandleError, MsgEncodable};
+use ln::msgs::{ErrorAction, HandleError, MsgEncodable};
 use ln::channelmonitor::ChannelMonitor;
 use ln::channelmanager::{PendingForwardHTLCInfo, HTLCFailReason};
 use ln::chan_utils::{TxCreationKeys,HTLCOutputInCommitment,HTLC_SUCCESS_TX_WEIGHT,HTLC_TIMEOUT_TX_WEIGHT};
@@ -1916,7 +1916,10 @@ impl Channel {
 	/// Called by channelmanager based on chain blocks being connected.
 	/// Note that we only need to use this to detect funding_signed, anything else is handled by
 	/// the channel_monitor.
-	pub fn block_connected(&mut self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) -> Option<msgs::FundingLocked> {
+	/// In case of Err, the channel may have been closed, at which point the standard requirements
+	/// apply - no calls may be made except those explicitly stated to be allowed post-shutdown.
+	/// Only returns an ErrorAction of DisconnectPeer, if Err.
+	pub fn block_connected(&mut self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) -> Result<Option<msgs::FundingLocked>, HandleError> {
 		let non_shutdown_state = self.channel_state & (!BOTH_SIDES_SHUTDOWN_MASK);
 		if self.funding_tx_confirmations > 0 {
 			if header.bitcoin_hash() != self.last_block_connected {
@@ -1940,10 +1943,10 @@ impl Channel {
 					//a protocol oversight, but I assume I'm just missing something.
 					let next_per_commitment_secret = self.build_local_commitment_secret(self.cur_local_commitment_transaction_number);
 					let next_per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &next_per_commitment_secret).unwrap();
-					return Some(msgs::FundingLocked {
+					return Ok(Some(msgs::FundingLocked {
 						channel_id: self.channel_id,
 						next_per_commitment_point: next_per_commitment_point,
-					});
+					}));
 				}
 			}
 		}
@@ -1955,6 +1958,7 @@ impl Channel {
 						tx.output[txo_idx].value != self.channel_value_satoshis {
 						self.channel_state = ChannelState::ShutdownComplete as u32;
 						self.channel_update_count += 1;
+						return Err(HandleError{err: "funding tx had wrong script/value", action: Some(ErrorAction::DisconnectPeer{msg: None})});
 					} else {
 						self.funding_tx_confirmations = 1;
 						self.short_channel_id = Some(((height as u64)          << (5*8)) |
@@ -1964,7 +1968,7 @@ impl Channel {
 				}
 			}
 		}
-		None
+		Ok(None)
 	}
 
 	/// Called by channelmanager based on chain blocks being disconnected.
diff --git a/src/ln/channelmanager.rs b/src/ln/channelmanager.rs
index 6c349fd0e..f39d0c093 100644
--- a/src/ln/channelmanager.rs
+++ b/src/ln/channelmanager.rs
@@ -1141,7 +1141,8 @@ impl ChainListener for ChannelManager {
 			let channel_state = channel_lock.borrow_parts();
 			let short_to_id = channel_state.short_to_id;
 			channel_state.by_id.retain(|_, channel| {
-				if let Some(funding_locked) = channel.block_connected(header, height, txn_matched, indexes_of_txn_matched) {
+				let chan_res = channel.block_connected(header, height, txn_matched, indexes_of_txn_matched);
+				if let Ok(Some(funding_locked)) = chan_res {
 					let announcement_sigs = match self.get_announcement_sigs(channel) {
 						Ok(res) => res,
 						Err(_e) => {
@@ -1155,6 +1156,16 @@ impl ChainListener for ChannelManager {
 						announcement_sigs: announcement_sigs
 					});
 					short_to_id.insert(channel.get_short_channel_id().unwrap(), channel.channel_id());
+				} else if let Err(e) = chan_res {
+					if let Some(msgs::ErrorAction::DisconnectPeer { msg }) = e.action {
+						new_events.push(events::Event::DisconnectPeer {
+							node_id: channel.get_their_node_id(),
+							msg: msg
+						});
+					} else { unreachable!(); }
+					if channel.is_shutdown() {
+						return false;
+					}
 				}
 				if let Some(funding_txo) = channel.get_funding_txo() {
 					for tx in txn_matched {
-- 
2.39.5