From 164af7f58e79014f7d8779e93959b94e9532c585 Mon Sep 17 00:00:00 2001
From: Devrandom <c1.devrandom@niftybox.net>
Date: Wed, 8 Jan 2020 11:50:15 -0800
Subject: [PATCH] Provide remote per-commitment point to sign_remote_commitment

---
 lightning/src/chain/keysinterface.rs        | 4 ++--
 lightning/src/ln/channel.rs                 | 6 +++---
 lightning/src/util/enforcing_trait_impls.rs | 6 +++---
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/lightning/src/chain/keysinterface.rs b/lightning/src/chain/keysinterface.rs
index 081ed7c3b..53fd9f78b 100644
--- a/lightning/src/chain/keysinterface.rs
+++ b/lightning/src/chain/keysinterface.rs
@@ -142,7 +142,7 @@ pub trait ChannelKeys : Send {
 	/// TODO: Document the things someone using this interface should enforce before signing.
 	/// TODO: Add more input vars to enable better checking (preferably removing commitment_tx and
 	/// making the callee generate it via some util function we expose)!
-	fn sign_remote_commitment<T: secp256k1::Signing>(&self, channel_value_satoshis: u64, channel_funding_redeemscript: &Script, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>, redeem_scripts: &Vec<Script>) -> Result<(Signature, Vec<Signature>), ()>;
+	fn sign_remote_commitment<T: secp256k1::Signing>(&self, channel_value_satoshis: u64, channel_funding_redeemscript: &Script, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>, redeem_scripts: &Vec<Script>, remote_per_commitment_point: &PublicKey) -> Result<(Signature, Vec<Signature>), ()>;
 
 	/// Create a signature for a (proposed) closing transaction.
 	///
@@ -184,7 +184,7 @@ impl ChannelKeys for InMemoryChannelKeys {
 	fn htlc_base_key(&self) -> &SecretKey { &self.htlc_base_key }
 	fn commitment_seed(&self) -> &[u8; 32] { &self.commitment_seed }
 
-	fn sign_remote_commitment<T: secp256k1::Signing>(&self, channel_value_satoshis: u64, channel_funding_redeemscript: &Script, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>, redeem_scripts: &Vec<Script>) -> Result<(Signature, Vec<Signature>), ()> {
+	fn sign_remote_commitment<T: secp256k1::Signing>(&self, channel_value_satoshis: u64, channel_funding_redeemscript: &Script, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>, redeem_scripts: &Vec<Script>, remote_per_commitment_point: &PublicKey) -> Result<(Signature, Vec<Signature>), ()> {
 		if commitment_tx.input.len() != 1 { return Err(()); }
 		if commitment_tx.output.len() != redeem_scripts.len() { return Err(()); }
 		let commitment_sighash = hash_to_message!(&bip143::SighashComponents::new(&commitment_tx).sighash_all(&commitment_tx.input[0], &channel_funding_redeemscript, channel_value_satoshis)[..]);
diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs
index 241a8b0dc..d057e04d9 100644
--- a/lightning/src/ln/channel.rs
+++ b/lightning/src/ln/channel.rs
@@ -1434,7 +1434,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		let commitment_tx = self.build_commitment_transaction(self.cur_remote_commitment_transaction_number, &remote_keys, false, false, self.feerate_per_kw);
 		let remote_initial_commitment_tx = commitment_tx.0;
 		let scripts = commitment_tx.3;
-		let remote_signature = self.local_keys.sign_remote_commitment(self.channel_value_satoshis, &self.get_funding_redeemscript(), self.feerate_per_kw, &remote_initial_commitment_tx, &remote_keys, &Vec::new(), self.our_to_self_delay, &self.secp_ctx, &scripts)
+		let remote_signature = self.local_keys.sign_remote_commitment(self.channel_value_satoshis, &self.get_funding_redeemscript(), self.feerate_per_kw, &remote_initial_commitment_tx, &remote_keys, &Vec::new(), self.our_to_self_delay, &self.secp_ctx, &scripts, &self.their_cur_commitment_point.unwrap())
 				.map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed"))?.0;
 
 		// We sign the "remote" commitment transaction, allowing them to broadcast the tx if they wish.
@@ -3162,7 +3162,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		let commitment_tx = self.build_commitment_transaction(self.cur_remote_commitment_transaction_number, &remote_keys, false, false, self.feerate_per_kw);
 		let remote_initial_commitment_tx = commitment_tx.0;
 		let scripts = commitment_tx.3;
-		Ok((self.local_keys.sign_remote_commitment(self.channel_value_satoshis, &self.get_funding_redeemscript(), self.feerate_per_kw, &remote_initial_commitment_tx, &remote_keys, &Vec::new(), self.our_to_self_delay, &self.secp_ctx, &scripts)
+		Ok((self.local_keys.sign_remote_commitment(self.channel_value_satoshis, &self.get_funding_redeemscript(), self.feerate_per_kw, &remote_initial_commitment_tx, &remote_keys, &Vec::new(), self.our_to_self_delay, &self.secp_ctx, &scripts, &self.their_cur_commitment_point.unwrap())
 				.map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed"))?.0, remote_initial_commitment_tx))
 	}
 
@@ -3470,7 +3470,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 				htlcs.push(htlc);
 			}
 
-			let res = self.local_keys.sign_remote_commitment(self.channel_value_satoshis, &self.get_funding_redeemscript(), feerate_per_kw, &remote_commitment_tx.0, &remote_keys, &htlcs, self.our_to_self_delay, &self.secp_ctx, &remote_commitment_tx.3)
+			let res = self.local_keys.sign_remote_commitment(self.channel_value_satoshis, &self.get_funding_redeemscript(), feerate_per_kw, &remote_commitment_tx.0, &remote_keys, &htlcs, self.our_to_self_delay, &self.secp_ctx, &remote_commitment_tx.3, &self.their_cur_commitment_point.unwrap())
 				.map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed"))?;
 			signature = res.0;
 			htlc_signatures = res.1;
diff --git a/lightning/src/util/enforcing_trait_impls.rs b/lightning/src/util/enforcing_trait_impls.rs
index 1586af1b6..39905b413 100644
--- a/lightning/src/util/enforcing_trait_impls.rs
+++ b/lightning/src/util/enforcing_trait_impls.rs
@@ -9,7 +9,7 @@ use bitcoin::blockdata::transaction::Transaction;
 use bitcoin::blockdata::script::Script;
 
 use secp256k1;
-use secp256k1::key::SecretKey;
+use secp256k1::key::{SecretKey, PublicKey};
 use secp256k1::{Secp256k1, Signature};
 
 /// Enforces some rules on ChannelKeys calls. Eventually we will probably want to expose a variant
@@ -35,7 +35,7 @@ impl ChannelKeys for EnforcingChannelKeys {
 	fn htlc_base_key(&self) -> &SecretKey { self.inner.htlc_base_key() }
 	fn commitment_seed(&self) -> &[u8; 32] { self.inner.commitment_seed() }
 
-	fn sign_remote_commitment<T: secp256k1::Signing>(&self, channel_value_satoshis: u64, channel_funding_script: &Script, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>, redeem_scripts: &Vec<Script>) -> Result<(Signature, Vec<Signature>), ()> {
+	fn sign_remote_commitment<T: secp256k1::Signing>(&self, channel_value_satoshis: u64, channel_funding_script: &Script, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>, redeem_scripts: &Vec<Script>, remote_per_commitment_point: &PublicKey) -> Result<(Signature, Vec<Signature>), ()> {
 		if commitment_tx.input.len() != 1 { panic!(); }
 		if commitment_tx.output.len() != redeem_scripts.len() { panic!(); }
 
@@ -51,7 +51,7 @@ impl ChannelKeys for EnforcingChannelKeys {
 			commitment_data.1 = cmp::max(commitment_number, commitment_data.1)
 		}
 
-		Ok(self.inner.sign_remote_commitment(channel_value_satoshis, channel_funding_script, feerate_per_kw, commitment_tx, keys, htlcs, to_self_delay, secp_ctx, redeem_scripts).unwrap())
+		Ok(self.inner.sign_remote_commitment(channel_value_satoshis, channel_funding_script, feerate_per_kw, commitment_tx, keys, htlcs, to_self_delay, secp_ctx, redeem_scripts, remote_per_commitment_point).unwrap())
 	}
 
 	fn sign_closing_transaction<T: secp256k1::Signing>(&self, channel_value_satoshis: u64, channel_funding_redeemscript: &Script, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
-- 
2.39.5