Add channel_keys_id as param in get_destination_script

This enables implementers to generate a different destination script for each channel.

Author: rmalonson

fuzz/src/chanmon_consistency.rs

@@ -270,7 +270,7 @@ impl SignerProvider for KeyProvider {
 		})
 	}
 
-	fn get_destination_script(&self) -> Result<ScriptBuf, ()> {
+	fn get_destination_script(&self, _channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> {
 		let secp_ctx = Secp256k1::signing_only();
 		let channel_monitor_claim_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, 2, self.node_secret[31]]).unwrap();
 		let our_channel_monitor_claim_key_hash = WPubkeyHash::hash(&PublicKey::from_secret_key(&secp_ctx, &channel_monitor_claim_key).serialize());

fuzz/src/full_stack.rs

@@ -392,7 +392,7 @@ impl SignerProvider for KeyProvider {
 		))
 	}
 
-	fn get_destination_script(&self) -> Result<ScriptBuf, ()> {
+	fn get_destination_script(&self, _channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> {
 		let secp_ctx = Secp256k1::signing_only();
 		let channel_monitor_claim_key = SecretKey::from_slice(&<Vec<u8>>::from_hex("0fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()[..]).unwrap();
 		let our_channel_monitor_claim_key_hash = WPubkeyHash::hash(&PublicKey::from_secret_key(&secp_ctx, &channel_monitor_claim_key).serialize());

fuzz/src/onion_message.rs

@@ -199,7 +199,7 @@ impl SignerProvider for KeyProvider {
 
 	fn read_chan_signer(&self, _data: &[u8]) -> Result<TestChannelSigner, DecodeError> { unreachable!() }
 
-	fn get_destination_script(&self) -> Result<ScriptBuf, ()> { unreachable!() }
+	fn get_destination_script(&self, _channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> { unreachable!() }
 
 	fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> { unreachable!() }
 }

lightning/src/ln/channel.rs

@@ -5960,7 +5960,7 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
 			}
 		}
 
-		let destination_script = match signer_provider.get_destination_script() {
+		let destination_script = match signer_provider.get_destination_script(channel_keys_id) {
 			Ok(script) => script,
 			Err(_) => return Err(APIError::ChannelUnavailable { err: "Failed to get destination script".to_owned()}),
 		};
@@ -6587,7 +6587,7 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
 			}
 		}
 
-		let destination_script = match signer_provider.get_destination_script() {
+		let destination_script = match signer_provider.get_destination_script(channel_keys_id) {
 			Ok(script) => script,
 			Err(_) => return Err(ChannelError::Close("Failed to get destination script".to_owned())),
 		};
@@ -7872,7 +7872,7 @@ mod tests {
 
 		fn read_chan_signer(&self, _data: &[u8]) -> Result<Self::Signer, DecodeError> { panic!(); }
 
-		fn get_destination_script(&self) -> Result<ScriptBuf, ()> {
+		fn get_destination_script(&self, _channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> {
 			let secp_ctx = Secp256k1::signing_only();
 			let channel_monitor_claim_key = SecretKey::from_slice(&<Vec<u8>>::from_hex("0fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()[..]).unwrap();
 			let channel_monitor_claim_key_hash = WPubkeyHash::hash(&PublicKey::from_secret_key(&secp_ctx, &channel_monitor_claim_key).serialize());

lightning/src/ln/functional_tests.rs

@@ -2590,8 +2590,8 @@ fn do_test_forming_justice_tx_from_monitor_updates(broadcast_initial_commitment:
 	// that a revoked commitment transaction is broadcasted
 	// (Similar to `revoked_output_claim` test but we get the justice tx + broadcast manually)
 	let chanmon_cfgs = create_chanmon_cfgs(2);
-	let destination_script0 = chanmon_cfgs[0].keys_manager.get_destination_script().unwrap();
-	let destination_script1 = chanmon_cfgs[1].keys_manager.get_destination_script().unwrap();
+	let destination_script0 = chanmon_cfgs[0].keys_manager.get_destination_script([0; 32]).unwrap();
+	let destination_script1 = chanmon_cfgs[1].keys_manager.get_destination_script([0; 32]).unwrap();
 	let persisters = vec![WatchtowerPersister::new(destination_script0),
 		WatchtowerPersister::new(destination_script1)];
 	let node_cfgs = create_node_cfgs_with_persisters(2, &chanmon_cfgs, persisters.iter().collect());

lightning/src/sign/mod.rs

@@ -906,8 +906,9 @@ pub trait SignerProvider {
 	/// If this function returns an error, this will result in a channel failing to open.
 	///
 	/// This method should return a different value each time it is called, to avoid linking
-	/// on-chain funds across channels as controlled to the same user.
-	fn get_destination_script(&self) -> Result<ScriptBuf, ()>;
+	/// on-chain funds across channels as controlled to the same user. `channel_keys_id` may be
+	/// used to derive a unique value for each channel.
+	fn get_destination_script(&self, channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()>;
 
 	/// Get a script pubkey which we will send funds to when closing a channel.
 	///
@@ -1795,7 +1796,7 @@ impl SignerProvider for KeysManager {
 		InMemorySigner::read(&mut io::Cursor::new(reader), self)
 	}
 
-	fn get_destination_script(&self) -> Result<ScriptBuf, ()> {
+	fn get_destination_script(&self, _channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> {
 		Ok(self.destination_script.clone())
 	}
 
@@ -1902,8 +1903,8 @@ impl SignerProvider for PhantomKeysManager {
 		self.inner.read_chan_signer(reader)
 	}
 
-	fn get_destination_script(&self) -> Result<ScriptBuf, ()> {
-		self.inner.get_destination_script()
+	fn get_destination_script(&self, channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> {
+		self.inner.get_destination_script(channel_keys_id)
 	}
 
 	fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {

lightning/src/util/test_utils.rs

@@ -192,7 +192,7 @@ impl SignerProvider for OnlyReadsKeysInterface {
 		))
 	}
 
-	fn get_destination_script(&self) -> Result<ScriptBuf, ()> { Err(()) }
+	fn get_destination_script(&self, _channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> { Err(()) }
 	fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> { Err(()) }
 }
 
@@ -1121,7 +1121,7 @@ impl SignerProvider for TestKeysInterface {
 		))
 	}
 
-	fn get_destination_script(&self) -> Result<ScriptBuf, ()> { self.backing.get_destination_script() }
+	fn get_destination_script(&self, channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> { self.backing.get_destination_script(channel_keys_id) }
 
 	fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {
 		match &mut *self.expectations.lock().unwrap() {