Allow(unused_imports) on prelude imports
[rust-lightning] / lightning / src / offers / merkle.rs
index d15039cd317d3ed8589ed6230cd3ccdd6487c7b6..8151631e6ef8410f0a66220ad48fd08cf57f9397 100644 (file)
@@ -16,6 +16,7 @@ use core::convert::AsRef;
 use crate::io;
 use crate::util::ser::{BigSize, Readable, Writeable, Writer};
 
+#[allow(unused_imports)]
 use crate::prelude::*;
 
 /// Valid type range for signature TLV records.
@@ -30,19 +31,41 @@ tlv_stream!(SignatureTlvStream, SignatureTlvStreamRef, SIGNATURE_TYPES, {
 ///
 /// [BIP 340]: https://github.com/bitcoin/bips/blob/master/bip-0340.mediawiki
 /// [BOLT 12]: https://github.com/rustyrussell/lightning-rfc/blob/guilt/offers/12-offer-encoding.md#signature-calculation
-pub struct TaggedHash(Message);
+#[derive(Clone, Debug, PartialEq)]
+pub struct TaggedHash {
+       tag: &'static str,
+       merkle_root: sha256::Hash,
+       digest: Message,
+}
 
 impl TaggedHash {
        /// Creates a tagged hash with the given parameters.
        ///
        /// Panics if `tlv_stream` is not a well-formed TLV stream containing at least one TLV record.
-       pub(super) fn new(tag: &str, tlv_stream: &[u8]) -> Self {
-               Self(message_digest(tag, tlv_stream))
+       pub(super) fn new(tag: &'static str, tlv_stream: &[u8]) -> Self {
+               let tag_hash = sha256::Hash::hash(tag.as_bytes());
+               let merkle_root = root_hash(tlv_stream);
+               let digest = Message::from_slice(tagged_hash(tag_hash, merkle_root).as_byte_array()).unwrap();
+               Self {
+                       tag,
+                       merkle_root,
+                       digest,
+               }
        }
 
        /// Returns the digest to sign.
        pub fn as_digest(&self) -> &Message {
-               &self.0
+               &self.digest
+       }
+
+       /// Returns the tag used in the tagged hash.
+       pub fn tag(&self) -> &str {
+               &self.tag
+       }
+
+       /// Returns the merkle root used in the tagged hash.
+       pub fn merkle_root(&self) -> sha256::Hash {
+               self.merkle_root
        }
 }
 
@@ -54,13 +77,28 @@ impl AsRef<TaggedHash> for TaggedHash {
 
 /// Error when signing messages.
 #[derive(Debug, PartialEq)]
-pub enum SignError<E> {
+pub enum SignError {
        /// User-defined error when signing the message.
-       Signing(E),
+       Signing,
        /// Error when verifying the produced signature using the given pubkey.
        Verification(secp256k1::Error),
 }
 
+/// A function for signing a [`TaggedHash`].
+pub(super) trait SignFn<T: AsRef<TaggedHash>> {
+       /// Signs a [`TaggedHash`] computed over the merkle root of `message`'s TLV stream.
+       fn sign(&self, message: &T) -> Result<Signature, ()>;
+}
+
+impl<F> SignFn<TaggedHash> for F
+where
+       F: Fn(&TaggedHash) -> Result<Signature, ()>,
+{
+       fn sign(&self, message: &TaggedHash) -> Result<Signature, ()> {
+               self(message)
+       }
+}
+
 /// Signs a [`TaggedHash`] computed over the merkle root of `message`'s TLV stream, checking if it
 /// can be verified with the supplied `pubkey`.
 ///
@@ -70,14 +108,14 @@ pub enum SignError<E> {
 ///
 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
-pub(super) fn sign_message<F, E, T>(
-       sign: F, message: &T, pubkey: PublicKey,
-) -> Result<Signature, SignError<E>>
+pub(super) fn sign_message<F, T>(
+       f: F, message: &T, pubkey: PublicKey,
+) -> Result<Signature, SignError>
 where
-       F: FnOnce(&T) -> Result<Signature, E>,
+       F: SignFn<T>,
        T: AsRef<TaggedHash>,
 {
-       let signature = sign(message).map_err(|e| SignError::Signing(e))?;
+       let signature = f.sign(message).map_err(|()| SignError::Signing)?;
 
        let digest = message.as_ref().as_digest();
        let pubkey = pubkey.into();
@@ -87,23 +125,15 @@ where
        Ok(signature)
 }
 
-/// Verifies the signature with a pubkey over the given bytes using a tagged hash as the message
+/// Verifies the signature with a pubkey over the given message using a tagged hash as the message
 /// digest.
-///
-/// Panics if `bytes` is not a well-formed TLV stream containing at least one TLV record.
 pub(super) fn verify_signature(
-       signature: &Signature, tag: &str, bytes: &[u8], pubkey: PublicKey,
+       signature: &Signature, message: &TaggedHash, pubkey: PublicKey,
 ) -> Result<(), secp256k1::Error> {
-       let digest = message_digest(tag, bytes);
+       let digest = message.as_digest();
        let pubkey = pubkey.into();
        let secp_ctx = Secp256k1::verification_only();
-       secp_ctx.verify_schnorr(signature, &digest, &pubkey)
-}
-
-pub(super) fn message_digest(tag: &str, bytes: &[u8]) -> Message {
-       let tag = sha256::Hash::hash(tag.as_bytes());
-       let merkle_root = root_hash(bytes);
-       Message::from_slice(&tagged_hash(tag, merkle_root)).unwrap()
+       secp_ctx.verify_schnorr(signature, digest, &pubkey)
 }
 
 /// Computes a merkle root hash for the given data, which must be a well-formed TLV stream
@@ -259,12 +289,13 @@ mod tests {
        use super::{SIGNATURE_TYPES, TlvStream, WithoutSignatures};
 
        use bitcoin::hashes::{Hash, sha256};
-       use bitcoin::secp256k1::{KeyPair, Secp256k1, SecretKey};
+       use bitcoin::hashes::hex::FromHex;
+       use bitcoin::secp256k1::{KeyPair, Message, Secp256k1, SecretKey};
        use bitcoin::secp256k1::schnorr::Signature;
-       use core::convert::Infallible;
        use crate::offers::offer::{Amount, OfferBuilder};
-       use crate::offers::invoice_request::InvoiceRequest;
+       use crate::offers::invoice_request::{InvoiceRequest, UnsignedInvoiceRequest};
        use crate::offers::parse::Bech32Encode;
+       use crate::offers::test_utils::{payer_pubkey, recipient_pubkey};
        use crate::util::ser::Writeable;
 
        #[test]
@@ -274,16 +305,16 @@ mod tests {
                macro_rules! tlv2 { () => { "02080000010000020003" } }
                macro_rules! tlv3 { () => { "03310266e4598d1d3c415f572a8488830b60f7e744ed9235eb0b1ba93283b315c0351800000000000000010000000000000002" } }
                assert_eq!(
-                       super::root_hash(&hex::decode(tlv1!()).unwrap()),
-                       sha256::Hash::from_slice(&hex::decode("b013756c8fee86503a0b4abdab4cddeb1af5d344ca6fc2fa8b6c08938caa6f93").unwrap()).unwrap(),
+                       super::root_hash(&<Vec<u8>>::from_hex(tlv1!()).unwrap()),
+                       sha256::Hash::from_slice(&<Vec<u8>>::from_hex("b013756c8fee86503a0b4abdab4cddeb1af5d344ca6fc2fa8b6c08938caa6f93").unwrap()).unwrap(),
                );
                assert_eq!(
-                       super::root_hash(&hex::decode(concat!(tlv1!(), tlv2!())).unwrap()),
-                       sha256::Hash::from_slice(&hex::decode("c3774abbf4815aa54ccaa026bff6581f01f3be5fe814c620a252534f434bc0d1").unwrap()).unwrap(),
+                       super::root_hash(&<Vec<u8>>::from_hex(concat!(tlv1!(), tlv2!())).unwrap()),
+                       sha256::Hash::from_slice(&<Vec<u8>>::from_hex("c3774abbf4815aa54ccaa026bff6581f01f3be5fe814c620a252534f434bc0d1").unwrap()).unwrap(),
                );
                assert_eq!(
-                       super::root_hash(&hex::decode(concat!(tlv1!(), tlv2!(), tlv3!())).unwrap()),
-                       sha256::Hash::from_slice(&hex::decode("ab2e79b1283b0b31e0b035258de23782df6b89a38cfa7237bde69aed1a658c5d").unwrap()).unwrap(),
+                       super::root_hash(&<Vec<u8>>::from_hex(concat!(tlv1!(), tlv2!(), tlv3!())).unwrap()),
+                       sha256::Hash::from_slice(&<Vec<u8>>::from_hex("ab2e79b1283b0b31e0b035258de23782df6b89a38cfa7237bde69aed1a658c5d").unwrap()).unwrap(),
                );
        }
 
@@ -291,11 +322,11 @@ mod tests {
        fn calculates_merkle_root_hash_from_invoice_request() {
                let secp_ctx = Secp256k1::new();
                let recipient_pubkey = {
-                       let secret_key = SecretKey::from_slice(&hex::decode("4141414141414141414141414141414141414141414141414141414141414141").unwrap()).unwrap();
+                       let secret_key = SecretKey::from_slice(&<Vec<u8>>::from_hex("4141414141414141414141414141414141414141414141414141414141414141").unwrap()).unwrap();
                        KeyPair::from_secret_key(&secp_ctx, &secret_key).public_key()
                };
                let payer_keys = {
-                       let secret_key = SecretKey::from_slice(&hex::decode("4242424242424242424242424242424242424242424242424242424242424242").unwrap()).unwrap();
+                       let secret_key = SecretKey::from_slice(&<Vec<u8>>::from_hex("4242424242424242424242424242424242424242424242424242424242424242").unwrap()).unwrap();
                        KeyPair::from_secret_key(&secp_ctx, &secret_key)
                };
 
@@ -305,8 +336,8 @@ mod tests {
                        .build_unchecked()
                        .request_invoice(vec![0; 8], payer_keys.public_key()).unwrap()
                        .build_unchecked()
-                       .sign::<_, Infallible>(
-                               |message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &payer_keys))
+                       .sign(|message: &UnsignedInvoiceRequest|
+                               Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &payer_keys))
                        )
                        .unwrap();
                assert_eq!(
@@ -315,14 +346,33 @@ mod tests {
                );
                assert_eq!(
                        super::root_hash(&invoice_request.bytes[..]),
-                       sha256::Hash::from_slice(&hex::decode("608407c18ad9a94d9ea2bcdbe170b6c20c462a7833a197621c916f78cf18e624").unwrap()).unwrap(),
+                       sha256::Hash::from_slice(&<Vec<u8>>::from_hex("608407c18ad9a94d9ea2bcdbe170b6c20c462a7833a197621c916f78cf18e624").unwrap()).unwrap(),
                );
                assert_eq!(
                        invoice_request.signature(),
-                       Signature::from_slice(&hex::decode("b8f83ea3288cfd6ea510cdb481472575141e8d8744157f98562d162cc1c472526fdb24befefbdebab4dbb726bbd1b7d8aec057f8fa805187e5950d2bbe0e5642").unwrap()).unwrap(),
+                       Signature::from_slice(&<Vec<u8>>::from_hex("b8f83ea3288cfd6ea510cdb481472575141e8d8744157f98562d162cc1c472526fdb24befefbdebab4dbb726bbd1b7d8aec057f8fa805187e5950d2bbe0e5642").unwrap()).unwrap(),
                );
        }
 
+        #[test]
+        fn compute_tagged_hash() {
+                let unsigned_invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+                        .amount_msats(1000)
+                        .build().unwrap()
+                        .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
+                        .payer_note("bar".into())
+                        .build().unwrap();
+
+                // Simply test that we can grab the tag and merkle root exposed by the accessor
+                // functions, then use them to succesfully compute a tagged hash.
+                let tagged_hash = unsigned_invoice_request.as_ref();
+                let expected_digest = unsigned_invoice_request.as_ref().as_digest();
+                let tag = sha256::Hash::hash(tagged_hash.tag().as_bytes());
+                let actual_digest = Message::from_slice(super::tagged_hash(tag, tagged_hash.merkle_root()).as_byte_array())
+                        .unwrap();
+                assert_eq!(*expected_digest, actual_digest);
+        }
+
        #[test]
        fn skips_encoding_signature_tlv_records() {
                let secp_ctx = Secp256k1::new();
@@ -340,8 +390,8 @@ mod tests {
                        .build_unchecked()
                        .request_invoice(vec![0; 8], payer_keys.public_key()).unwrap()
                        .build_unchecked()
-                       .sign::<_, Infallible>(
-                               |message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &payer_keys))
+                       .sign(|message: &UnsignedInvoiceRequest|
+                               Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &payer_keys))
                        )
                        .unwrap();
 
@@ -372,8 +422,8 @@ mod tests {
                        .build_unchecked()
                        .request_invoice(vec![0; 8], payer_keys.public_key()).unwrap()
                        .build_unchecked()
-                       .sign::<_, Infallible>(
-                               |message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &payer_keys))
+                       .sign(|message: &UnsignedInvoiceRequest|
+                               Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &payer_keys))
                        )
                        .unwrap();