From 78c17d5d77403681801fe5aaacd0d234eb36c363 Mon Sep 17 00:00:00 2001
From: Devrandom <c1.devrandom@niftybox.net>
Date: Mon, 13 Jan 2020 12:16:26 -0800
Subject: [PATCH] more checking

---
 lightning/src/chain/keysinterface.rs | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/lightning/src/chain/keysinterface.rs b/lightning/src/chain/keysinterface.rs
index cc5a9580b..3e4cb612f 100644
--- a/lightning/src/chain/keysinterface.rs
+++ b/lightning/src/chain/keysinterface.rs
@@ -139,7 +139,7 @@ pub trait ChannelKeys : Send {
 	///
 	/// Note that if signing fails or is rejected, the channel will be force-closed.
 	///
-	/// The commitment_tx follows BIP-69 lexicographical ordering.
+	/// The commitment_tx follows BOLT-3 lexicographical output ordering and has a single input.
 	///
 	/// The redeem_scripts vector is 1-1 mapped to commitment_tx outputs.  For p2wpkh, the
 	/// redeem script should be empty.
@@ -147,11 +147,18 @@ 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>, remote_per_commitment_point: &PublicKey) -> 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.
 	///
-	/// The closing_tx follows BIP-69 lexicographical ordering.
+	/// The closing_tx follows BOLT-3 lexicographical output ordering and has a single input.
 	///
 	/// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
 	/// chosen to forgo their output as dust.
@@ -194,6 +201,18 @@ impl ChannelKeys for InMemoryChannelKeys {
 	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(()); }
+
+		for (out, redeem_script) in commitment_tx.output.iter().zip(redeem_scripts.iter()) {
+			if out.script_pubkey.is_v0_p2wpkh() {
+				if !redeem_script.is_empty() {
+					return Err(())
+				}
+			} else {
+				if out.script_pubkey != redeem_script.to_v0_p2wsh() {
+					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)[..]);
 		let commitment_sig = secp_ctx.sign(&commitment_sighash, &self.funding_key);
 
-- 
2.39.5