Prefactor -> Introduce sign_message on NodeSigner, to be used by LSPS5/service when signing notifications

Author: martinsaposnic

fuzz/src/chanmon_consistency.rs

@@ -365,6 +365,10 @@ impl NodeSigner for KeyProvider {
 		let secp_ctx = Secp256k1::signing_only();
 		Ok(secp_ctx.sign_ecdsa(&msg_hash, &self.node_secret))
 	}
+
+	fn sign_message(&self, msg: &[u8]) -> Result<String, ()> {
+		Ok(lightning::util::message_signing::sign(msg, &self.node_secret))
+	}
 }
 
 impl SignerProvider for KeyProvider {

fuzz/src/full_stack.rs

@@ -436,6 +436,10 @@ impl NodeSigner for KeyProvider {
 		Ok(secp_ctx.sign_ecdsa(&msg_hash, &self.node_secret))
 	}
 
+	fn sign_message(&self, msg: &[u8]) -> Result<String, ()> {
+		Ok(lightning::util::message_signing::sign(msg, &self.node_secret))
+	}
+
 	fn get_peer_storage_key(&self) -> PeerStorageKey {
 		PeerStorageKey { inner: [42; 32] }
 	}

fuzz/src/onion_message.rs

@@ -277,6 +277,10 @@ impl NodeSigner for KeyProvider {
 		unreachable!()
 	}
 
+	fn sign_message(&self, msg: &[u8]) -> Result<String, ()> {
+		Ok(lightning::util::message_signing::sign(msg, &self.node_secret))
+	}
+
 	fn get_peer_storage_key(&self) -> PeerStorageKey {
 		unreachable!()
 	}

lightning/src/ln/blinded_payment_tests.rs

@@ -1633,6 +1633,8 @@ fn route_blinding_spec_test_vector() {
 			&self, _invoice: &UnsignedBolt12Invoice,
 		) -> Result<schnorr::Signature, ()> { unreachable!() }
 		fn sign_gossip_message(&self, _msg: UnsignedGossipMessage) -> Result<Signature, ()> { unreachable!() }
+
+		fn sign_message(&self, msg: &[u8]) -> Result<String, ()> { Ok(crate::util::message_signing::sign(msg, &self.node_secret)) }
 	}
 	let logger = test_utils::TestLogger::with_id("".to_owned());
 
@@ -1944,6 +1946,7 @@ fn test_trampoline_inbound_payment_decoding() {
 			&self, _invoice: &UnsignedBolt12Invoice,
 		) -> Result<schnorr::Signature, ()> { unreachable!() }
 		fn sign_gossip_message(&self, _msg: UnsignedGossipMessage) -> Result<Signature, ()> { unreachable!() }
+		fn sign_message(&self, msg: &[u8]) -> Result<String, ()> { Ok(crate::util::message_signing::sign(msg, &self.node_secret)) }
 	}
 	let logger = test_utils::TestLogger::with_id("".to_owned());
 

lightning/src/sign/mod.rs

@@ -930,6 +930,17 @@ pub trait NodeSigner {
 	/// message to be broadcast, as otherwise it may prevent one from receiving funds over the
 	/// corresponding channel.
 	fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()>;
+
+	/// Sign an arbitrary message with the node's secret key.
+	///
+	/// Creates a digital signature of a message given the node's secret. The message is prefixed
+	/// with "Lightning Signed Message:" before signing. See [this description of the format](https://web.archive.org/web/20191010011846/https://twitter.com/rusty_twit/status/1182102005914800128)
+	/// for more details.
+	///
+	/// A receiver knowing the node's id and the message can be sure that the signature was generated by the caller.
+	/// An `Err` can be returned to signal that the signer is unavailable / cannot produce a valid
+	/// signature.
+	fn sign_message(&self, msg: &[u8]) -> Result<String, ()>;
 }
 
 /// A trait that describes a wallet capable of creating a spending [`Transaction`] from a set of
@@ -2209,6 +2220,10 @@ impl NodeSigner for KeysManager {
 		let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
 		Ok(self.secp_ctx.sign_ecdsa(&msg_hash, &self.node_secret))
 	}
+
+	fn sign_message(&self, msg: &[u8]) -> Result<String, ()> {
+		Ok(crate::util::message_signing::sign(msg, &self.node_secret))
+	}
 }
 
 impl OutputSpender for KeysManager {
@@ -2374,6 +2389,10 @@ impl NodeSigner for PhantomKeysManager {
 	fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()> {
 		self.inner.sign_gossip_message(msg)
 	}
+
+	fn sign_message(&self, msg: &[u8]) -> Result<String, ()> {
+		self.inner.sign_message(msg)
+	}
 }
 
 impl OutputSpender for PhantomKeysManager {

lightning/src/util/dyn_signer.rs

@@ -211,6 +211,7 @@ delegate!(DynKeysInterface, NodeSigner,
 inner,
 	fn get_node_id(, recipient: Recipient) -> Result<PublicKey, ()>,
 	fn sign_gossip_message(, msg: UnsignedGossipMessage) -> Result<Signature, ()>,
+	fn sign_message(, msg: &[u8]) -> Result<String, ()>,
 	fn ecdh(, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()>,
 	fn sign_invoice(, invoice: &RawBolt11Invoice, recipient: Recipient) -> Result<RecoverableSignature, ()>,
 	fn sign_bolt12_invoice(,
@@ -278,6 +279,7 @@ delegate!(DynPhantomKeysInterface, NodeSigner,
 	inner,
 	fn get_node_id(, recipient: Recipient) -> Result<PublicKey, ()>,
 	fn sign_gossip_message(, msg: UnsignedGossipMessage) -> Result<Signature, ()>,
+	fn sign_message(, msg: &[u8]) -> Result<String, ()>,
 	fn ecdh(, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()>,
 	fn sign_invoice(, invoice: &RawBolt11Invoice, recipient: Recipient) -> Result<RecoverableSignature, ()>,
 	fn sign_bolt12_invoice(, invoice: &crate::offers::invoice::UnsignedBolt12Invoice

lightning/src/util/test_utils.rs

@@ -1569,6 +1569,10 @@ impl NodeSigner for TestNodeSigner {
 	fn sign_gossip_message(&self, _msg: msgs::UnsignedGossipMessage) -> Result<Signature, ()> {
 		unreachable!()
 	}
+
+	fn sign_message(&self, msg: &[u8]) -> Result<String, ()> {
+		Ok(crate::util::message_signing::sign(msg, &self.node_secret))
+	}
 }
 
 pub struct TestKeysInterface {
@@ -1631,6 +1635,10 @@ impl NodeSigner for TestKeysInterface {
 	fn sign_gossip_message(&self, msg: msgs::UnsignedGossipMessage) -> Result<Signature, ()> {
 		self.backing.sign_gossip_message(msg)
 	}
+
+	fn sign_message(&self, msg: &[u8]) -> Result<String, ()> {
+		self.backing.sign_message(msg)
+	}
 }
 
 impl SignerProvider for TestKeysInterface {