f - build_signed with error

Author: jkczyz

lightning/src/offers/offer.rs

@@ -13,7 +13,7 @@ use bitcoin::blockdata::constants::genesis_block;
 use bitcoin::hash_types::BlockHash;
 use bitcoin::hashes::{Hash, sha256};
 use bitcoin::network::constants::Network;
-use bitcoin::secp256k1::{Message, PublicKey};
+use bitcoin::secp256k1::{Message, PublicKey, Secp256k1, self};
 use bitcoin::secp256k1::schnorr::Signature;
 use core::num::NonZeroU64;
 use core::ops::{Bound, RangeBounds};
@@ -155,11 +155,10 @@ impl OfferBuilder {
 	}
 
 	///
-	pub fn build_signed<F: FnOnce(&Message) -> Signature>(self, sign: F) -> Offer {
-		let mut offer = self.build();
-		let digest = offer.to_message_digest();
-		offer.signature = Some(sign(&digest));
-		offer
+	pub fn build_signed<F>(self, sign: F) -> Result<Offer, secp256k1::Error>
+	where F: FnOnce(&Message) -> Signature
+	{
+		self.build().sign(sign)
 	}
 }
 
@@ -265,6 +264,20 @@ impl Offer {
 		self.signature.as_ref()
 	}
 
+	fn sign<F>(mut self, sign: F) -> Result<Self, secp256k1::Error>
+	where F: FnOnce(&Message) -> Signature
+	{
+		let digest = self.to_message_digest();
+		let signature = sign(&digest);
+
+		let secp_ctx = Secp256k1::verification_only();
+		let pubkey = self.node_id();
+		secp_ctx.verify_schnorr(&signature, &digest, &pubkey.into())?;
+
+		self.signature = Some(signature);
+		Ok(self)
+	}
+
 	fn to_message_digest(&self) -> Message {
 		Self::message_digest(self.id)
 	}
@@ -393,7 +406,7 @@ mod tests {
 	}
 
 	fn privkey() -> SecretKey {
-		SecretKey::from_slice(&[45; 32]).unwrap()
+		SecretKey::from_slice(&[42; 32]).unwrap()
 	}
 
 	fn blinded_pubkey(byte: u8) -> PublicKey {
@@ -448,13 +461,16 @@ mod tests {
 		let pubkey = PublicKey::from(keys);
 
 		let offer = OfferBuilder::new("foo".into(), Destination::NodeId(pubkey))
-			.build_signed(|digest| secp_ctx.sign_schnorr_no_aux_rand(digest, &keys));
+			.build_signed(|digest| secp_ctx.sign_schnorr_no_aux_rand(digest, &keys))
+			.unwrap();
 		assert!(offer.signature().is_some());
 
-		let message_digest = offer.to_message_digest();
-		let signature = offer.signature().unwrap();
-		let x_only_pubkey = keys.x_only_public_key().0;
-		assert!(secp_ctx.verify_schnorr(signature, &message_digest, &x_only_pubkey).is_ok());
+		let wrong_keys = KeyPair::from_secret_key(&secp_ctx, &blinded_privkey(99));
+		assert!(
+			OfferBuilder::new("foo".into(), Destination::NodeId(pubkey))
+				.build_signed(|digest| secp_ctx.sign_schnorr_no_aux_rand(digest, &wrong_keys))
+				.is_err()
+		);
 	}
 
 	#[test]