Provide remote channel public keys to signer

.gitignore

@@ -1,4 +1,5 @@
 /target/
+/hfuzz_target/
 /net-tokio/target/
 **/*.rs.bk
 Cargo.lock

fuzz/src/chanmon_consistency.rs

@@ -158,7 +158,7 @@ impl KeysInterface for KeyProvider {
 			delayed_payment_base_key:  SecretKey::from_slice(&[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, self.node_id]).unwrap(),
 			htlc_base_key:             SecretKey::from_slice(&[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, self.node_id]).unwrap(),
 			commitment_seed: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 9, self.node_id],
-			remote_funding_pubkey: None,
+			remote_channel_pubkeys: None,
 		})
 	}
 

fuzz/src/full_stack.rs

@@ -257,7 +257,7 @@ impl KeysInterface for KeyProvider {
 				delayed_payment_base_key:  SecretKey::from_slice(&[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, ctr]).unwrap(),
 				htlc_base_key:             SecretKey::from_slice(&[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, ctr]).unwrap(),
 				commitment_seed: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, ctr],
-				remote_funding_pubkey: None,
+				remote_channel_pubkeys: None,
 			}
 		} else {
 			InMemoryChannelKeys {
@@ -267,7 +267,7 @@ impl KeysInterface for KeyProvider {
 				delayed_payment_base_key:  SecretKey::from_slice(&[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, ctr]).unwrap(),
 				htlc_base_key:             SecretKey::from_slice(&[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, ctr]).unwrap(),
 				commitment_seed: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 12, ctr],
-				remote_funding_pubkey: None,
+				remote_channel_pubkeys: None,
 			}
 		})
 	}

lightning/src/chain/keysinterface.rs

@@ -24,7 +24,7 @@ use util::logger::Logger;
 use util::ser::Writeable;
 
 use ln::chan_utils;
-use ln::chan_utils::{TxCreationKeys, HTLCOutputInCommitment, make_funding_redeemscript};
+use ln::chan_utils::{TxCreationKeys, HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys};
 use ln::msgs;
 
 use std::sync::Arc;
@@ -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, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()>;
+	fn sign_remote_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, channel_value_satoshis: u64, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()>;
 
 	/// Create a signature for a (proposed) closing transaction.
 	///
@@ -158,11 +158,11 @@ pub trait ChannelKeys : Send {
 	/// protocol.
 	fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
 
-	/// Set the remote funding key.  This is done immediately on incoming channels
+	/// Set the remote channel basepoints.  This is done immediately on incoming channels
 	/// and as soon as the channel is accepted on outgoing channels.
 	///
 	/// Will be called before any signatures are applied.
-	fn set_remote_funding_pubkey(&mut self, key: &PublicKey);
+	fn set_remote_channel_pubkeys(&mut self, channel_points: &ChannelPublicKeys);
 }
 
 #[derive(Clone)]
@@ -181,7 +181,7 @@ pub struct InMemoryChannelKeys {
 	/// Commitment seed
 	pub commitment_seed: [u8; 32],
 	/// Remote funding pubkey
-	pub remote_funding_pubkey: Option<PublicKey>,
+	pub remote_channel_pubkeys: Option<ChannelPublicKeys>,
 }
 
 impl ChannelKeys for InMemoryChannelKeys {
@@ -192,12 +192,12 @@ 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, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()> {
+	fn sign_remote_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, channel_value_satoshis: u64, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()> {
 		if commitment_tx.input.len() != 1 { return Err(()); }
 
 		let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
-		let remote_funding_pubkey = self.remote_funding_pubkey.as_ref().expect("must set remote funding key before signing");
-		let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, remote_funding_pubkey);
+		let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
+		let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
 
 		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);
@@ -236,9 +236,9 @@ impl ChannelKeys for InMemoryChannelKeys {
 		Ok(secp_ctx.sign(&msghash, &self.funding_key))
 	}
 
-	fn set_remote_funding_pubkey(&mut self, key: &PublicKey) {
-		assert!(self.remote_funding_pubkey.is_none(), "Already set remote funding key");
-		self.remote_funding_pubkey = Some(*key);
+	fn set_remote_channel_pubkeys(&mut self, channel_pubkeys: &ChannelPublicKeys) {
+		assert!(self.remote_channel_pubkeys.is_none(), "Already set remote channel pubkeys");
+		self.remote_channel_pubkeys = Some(channel_pubkeys.clone());
 	}
 }
 
@@ -249,7 +249,7 @@ impl_writeable!(InMemoryChannelKeys, 0, {
 	delayed_payment_base_key,
 	htlc_base_key,
 	commitment_seed,
-	remote_funding_pubkey
+	remote_channel_pubkeys
 });
 
 /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key
@@ -398,7 +398,7 @@ impl KeysInterface for KeysManager {
 			delayed_payment_base_key,
 			htlc_base_key,
 			commitment_seed,
-			remote_funding_pubkey: None,
+			remote_channel_pubkeys: None,
 		}
 	}
 

lightning/src/ln/chan_utils.rs

@@ -18,7 +18,7 @@ use ln::channelmanager::{PaymentHash, PaymentPreimage};
 use ln::msgs::DecodeError;
 use util::ser::{Readable, Writeable, Writer, WriterWriteAdaptor};
 
-use secp256k1::key::{SecretKey,PublicKey};
+use secp256k1::key::{SecretKey, PublicKey};
 use secp256k1::{Secp256k1, Signature};
 use secp256k1;
 
@@ -118,24 +118,57 @@ pub(super) fn derive_public_revocation_key<T: secp256k1::Verification>(secp_ctx:
 
 /// The set of public keys which are used in the creation of one commitment transaction.
 /// These are derived from the channel base keys and per-commitment data.
+#[derive(PartialEq)]
 pub struct TxCreationKeys {
 	/// The per-commitment public key which was used to derive the other keys.
 	pub per_commitment_point: PublicKey,
 	/// The revocation key which is used to allow the owner of the commitment transaction to
 	/// provide their counterparty the ability to punish them if they broadcast an old state.
-	pub revocation_key: PublicKey,
+	pub(crate) revocation_key: PublicKey,
 	/// A's HTLC Key
-	pub a_htlc_key: PublicKey,
+	pub(crate) a_htlc_key: PublicKey,
 	/// B's HTLC Key
-	pub b_htlc_key: PublicKey,
+	pub(crate) b_htlc_key: PublicKey,
 	/// A's Payment Key (which isn't allowed to be spent from for some delay)
-	pub a_delayed_payment_key: PublicKey,
+	pub(crate) a_delayed_payment_key: PublicKey,
 	/// B's Payment Key
-	pub b_payment_key: PublicKey,
+	pub(crate) b_payment_key: PublicKey,
 }
 
+/// One counterparty's public keys which do not change over the life of a channel.
+#[derive(Clone)]
+pub struct ChannelPublicKeys {
+	/// The public key which is used to sign all commitment transactions, as it appears in the
+	/// on-chain channel lock-in 2-of-2 multisig output.
+	pub funding_pubkey: PublicKey,
+	/// The base point which is used (with derive_public_revocation_key) to derive per-commitment
+	/// revocation keys. The per-commitment revocation private key is then revealed by the owner of
+	/// a commitment transaction so that their counterparty can claim all available funds if they
+	/// broadcast an old state.
+	pub revocation_basepoint: PublicKey,
+	/// The base point which is used (with derive_public_key) to derive a per-commitment payment
+	/// public key which receives immediately-spendable non-HTLC-encumbered funds.
+	pub payment_basepoint: PublicKey,
+	/// The base point which is used (with derive_public_key) to derive a per-commitment payment
+	/// public key which receives non-HTLC-encumbered funds which are only available for spending
+	/// after some delay (or can be claimed via the revocation path).
+	pub delayed_payment_basepoint: PublicKey,
+	/// The base point which is used (with derive_public_key) to derive a per-commitment public key
+	/// which is used to encumber HTLC-in-flight outputs.
+	pub htlc_basepoint: PublicKey,
+}
+
+impl_writeable!(ChannelPublicKeys, 33*5, {
+	funding_pubkey,
+	revocation_basepoint,
+	payment_basepoint,
+	delayed_payment_basepoint,
+	htlc_basepoint
+});
+
+
 impl TxCreationKeys {
-	pub(super) fn new<T: secp256k1::Signing + secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, a_delayed_payment_base: &PublicKey, a_htlc_base: &PublicKey, b_revocation_base: &PublicKey, b_payment_base: &PublicKey, b_htlc_base: &PublicKey) -> Result<TxCreationKeys, secp256k1::Error> {
+	pub(crate) fn new<T: secp256k1::Signing + secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, a_delayed_payment_base: &PublicKey, a_htlc_base: &PublicKey, b_revocation_base: &PublicKey, b_payment_base: &PublicKey, b_htlc_base: &PublicKey) -> Result<TxCreationKeys, secp256k1::Error> {
 		Ok(TxCreationKeys {
 			per_commitment_point: per_commitment_point.clone(),
 			revocation_key: derive_public_revocation_key(&secp_ctx, &per_commitment_point, &b_revocation_base)?,