Make MultiSigner use compressed ECDSA public key (#4502)

* Don't use compressed ecdsa public key in verify

* Make `ECDSA` public support compressed

* Make it a proper `expect` message

substrate/primitives/runtime/src/lib.rs

@@ -212,7 +212,7 @@ pub enum MultiSigner {
 	Ed25519(ed25519::Public),
 	/// An Sr25519 identity.
 	Sr25519(sr25519::Public),
-	/// An SECP256k1/ECDSA identity (actually, the Blake2 hash of the pub key).
+	/// An SECP256k1/ECDSA identity (actually, the Blake2 hash of the compressed pub key).
 	Ecdsa(ecdsa::Public),
 }
 
@@ -246,7 +246,9 @@ impl traits::IdentifyAccount for MultiSigner {
 		match self {
 			MultiSigner::Ed25519(who) => <[u8; 32]>::from(who).into(),
 			MultiSigner::Sr25519(who) => <[u8; 32]>::from(who).into(),
-			MultiSigner::Ecdsa(who) => sp_io::hashing::blake2_256(who.as_ref()).into(),
+			MultiSigner::Ecdsa(who) => sp_io::hashing::blake2_256(
+				&who.as_compressed().expect("`who` is a valid `ECDSA` public key; qed")[..],
+			).into(),
 		}
 	}
 }
@@ -688,8 +690,9 @@ pub fn print(print: impl traits::Printable) {
 
 #[cfg(test)]
 mod tests {
-	use crate::DispatchError;
+	use super::*;
 	use codec::{Encode, Decode};
+	use sp_core::crypto::Pair;
 
 	#[test]
 	fn opaque_extrinsic_serialization() {
@@ -716,4 +719,20 @@ mod tests {
 			},
 		);
 	}
+
+	#[test]
+	fn multi_signature_ecdsa_verify_works() {
+		let msg = &b"test-message"[..];
+		let (pair, _) = ecdsa::Pair::generate();
+
+		let signature = pair.sign(&msg);
+		assert!(ecdsa::Pair::verify(&signature, msg, &pair.public()));
+
+		let multi_sig = MultiSignature::from(signature);
+		let multi_signer = MultiSigner::from(pair.public());
+		assert!(multi_sig.verify(msg, &multi_signer.into_account()));
+
+		let multi_signer = MultiSigner::from(pair.public().into_compressed().unwrap());
+		assert!(multi_sig.verify(msg, &multi_signer.into_account()));
+	}
 }

substrate/primitives/runtime/src/traits.rs

@@ -102,7 +102,7 @@ impl Verify for sp_core::ecdsa::Signature {
 			self.as_ref(),
 			&sp_io::hashing::blake2_256(msg.get()),
 		) {
-			Ok(pubkey) => <dyn AsRef<[u8]>>::as_ref(signer) == &pubkey[..],
+			Ok(pubkey) => signer.as_compressed().map(|s| &s[..] == &pubkey[..]).unwrap_or(false),
 			_ => false,
 		}
 	}
@@ -1307,8 +1307,9 @@ pub trait BlockIdTo<Block: self::Block> {
 
 #[cfg(test)]
 mod tests {
-	use super::AccountIdConversion;
+	use super::*;
 	use crate::codec::{Encode, Decode, Input};
+	use sp_core::{crypto::Pair, ecdsa};
 
 	mod t {
 		use sp_core::crypto::KeyTypeId;
@@ -1388,4 +1389,16 @@ mod tests {
 		assert_eq!(t.remaining_len(), Ok(None));
 		assert_eq!(buffer, [0, 0]);
 	}
+
+	#[test]
+	fn ecdsa_verify_works() {
+		let msg = &b"test-message"[..];
+		let (pair, _) = ecdsa::Pair::generate();
+
+		let signature = pair.sign(&msg);
+		assert!(ecdsa::Pair::verify(&signature, msg, &pair.public()));
+
+		assert!(signature.verify(msg, &pair.public()));
+		assert!(signature.verify(msg, &pair.public().into_compressed().unwrap()));
+	}
 }