uahf: OP_RETURN replay protection

Cargo.lock

@@ -4,6 +4,7 @@ version = "0.1.0"
 dependencies = [
  "chain 0.1.0",
  "db 0.1.0",
+ "lazy_static 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "network 0.1.0",
  "parking_lot 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",

network/src/consensus.rs

@@ -2,25 +2,6 @@ use std::cmp::max;
 use hash::H256;
 use {Magic, Deployment};
 
-#[derive(Debug, Clone, Copy)]
-/// Concurrent consensus rule forks.
-pub enum ConsensusFork {
-	/// No fork.
-	NoFork,
-	/// SegWit2x (aka The New York Agreement).
-	/// Briefly: SegWit + blocks up to 2MB.
-	/// Technical specification:
-	/// Segregated Witness (Consensus layer) - https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki
-	/// Block size increase to 2MB - https://github.com/bitcoin/bips/blob/master/bip-0102.mediawiki
-	SegWit2x(u32),
-	/// Bitcoin Cash (aka UAHF).
-	/// Briefly: no SegWit + blocks up to 8MB + replay protection.
-	/// Technical specification:
-	/// UAHF Technical Specification - https://github.com/Bitcoin-UAHF/spec/blob/master/uahf-technical-spec.md
-	/// BUIP-HF Digest for replay protected signature verification across hard forks - https://github.com/Bitcoin-UAHF/spec/blob/master/replay-protected-sighash.md
-	BitcoinCash(u32),
-}
-
 #[derive(Debug, Clone)]
 /// Parameters that influence chain consensus.
 pub struct ConsensusParams {
@@ -50,6 +31,25 @@ pub struct ConsensusParams {
 	pub segwit_deployment: Option<Deployment>,
 }
 
+#[derive(Debug, Clone, Copy)]
+/// Concurrent consensus rule forks.
+pub enum ConsensusFork {
+	/// No fork.
+	NoFork,
+	/// SegWit2x (aka The New York Agreement).
+	/// Briefly: SegWit + blocks up to 2MB.
+	/// Technical specification:
+	/// Segregated Witness (Consensus layer) - https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki
+	/// Block size increase to 2MB - https://github.com/bitcoin/bips/blob/master/bip-0102.mediawiki
+	SegWit2x(u32),
+	/// Bitcoin Cash (aka UAHF).
+	/// Briefly: no SegWit + blocks up to 8MB + replay protection.
+	/// Technical specification:
+	/// UAHF Technical Specification - https://github.com/Bitcoin-UAHF/spec/blob/master/uahf-technical-spec.md
+	/// BUIP-HF Digest for replay protected signature verification across hard forks - https://github.com/Bitcoin-UAHF/spec/blob/master/replay-protected-sighash.md
+	BitcoinCash(u32),
+}
+
 impl ConsensusParams {
 	pub fn new(magic: Magic, fork: ConsensusFork) -> Self {
 		match magic {

script/src/builder.rs

@@ -126,4 +126,9 @@ impl Builder {
 	pub fn into_script(self) -> Script {
 		Script::new(self.data)
 	}
+
+	/// Builds final script bytes
+	pub fn into_bytes(self) -> Bytes {
+		self.data
+	}
 }

verification/Cargo.toml

@@ -5,6 +5,7 @@ authors = ["Nikolay Volf <nikvolf@gmail.com>"]
 
 [dependencies]
 time = "0.1"
+lazy_static = "0.2"
 log = "0.3"
 rayon = "0.7"
 parking_lot = "0.4"

verification/src/accept_transaction.rs

@@ -1,9 +1,11 @@
 use primitives::hash::H256;
+use primitives::bytes::Bytes;
 use db::{TransactionMetaProvider, TransactionOutputProvider, BlockHeaderProvider};
-use network::ConsensusParams;
+use network::{ConsensusParams, ConsensusFork};
 use script::{Script, verify_script, VerificationFlags, TransactionSignatureChecker, TransactionInputSigner};
 use duplex_store::DuplexTransactionOutputProvider;
 use deployments::Deployments;
+use script::Builder;
 use sigops::transaction_sigops;
 use canon::CanonTransaction;
 use constants::{COINBASE_MATURITY};
@@ -15,6 +17,7 @@ pub struct TransactionAcceptor<'a> {
 	pub maturity: TransactionMaturity<'a>,
 	pub overspent: TransactionOverspent<'a>,
 	pub double_spent: TransactionDoubleSpend<'a>,
+	pub return_replay_protection: TransactionReturnReplayProtection<'a>,
 	pub eval: TransactionEval<'a>,
 }
 
@@ -41,6 +44,7 @@ impl<'a> TransactionAcceptor<'a> {
 			maturity: TransactionMaturity::new(transaction, meta_store, height),
 			overspent: TransactionOverspent::new(transaction, output_store),
 			double_spent: TransactionDoubleSpend::new(transaction, output_store),
+			return_replay_protection: TransactionReturnReplayProtection::new(transaction, consensus, height),
 			eval: TransactionEval::new(transaction, output_store, consensus, height, time, deployments, headers),
 		}
 	}
@@ -51,6 +55,7 @@ impl<'a> TransactionAcceptor<'a> {
 		try!(self.maturity.check());
 		try!(self.overspent.check());
 		try!(self.double_spent.check());
+		try!(self.return_replay_protection.check());
 		try!(self.eval.check());
 		Ok(())
 	}
@@ -62,6 +67,7 @@ pub struct MemoryPoolTransactionAcceptor<'a> {
 	pub overspent: TransactionOverspent<'a>,
 	pub sigops: TransactionSigops<'a>,
 	pub double_spent: TransactionDoubleSpend<'a>,
+	pub return_replay_protection: TransactionReturnReplayProtection<'a>,
 	pub eval: TransactionEval<'a>,
 }
 
@@ -87,6 +93,7 @@ impl<'a> MemoryPoolTransactionAcceptor<'a> {
 			overspent: TransactionOverspent::new(transaction, output_store),
 			sigops: TransactionSigops::new(transaction, output_store, consensus, max_block_sigops, time),
 			double_spent: TransactionDoubleSpend::new(transaction, output_store),
+			return_replay_protection: TransactionReturnReplayProtection::new(transaction, consensus, height),
 			eval: TransactionEval::new(transaction, output_store, consensus, height, time, deployments, headers),
 		}
 	}
@@ -99,6 +106,7 @@ impl<'a> MemoryPoolTransactionAcceptor<'a> {
 		try!(self.overspent.check());
 		try!(self.sigops.check());
 		try!(self.double_spent.check());
+		try!(self.return_replay_protection.check());
 		try!(self.eval.check());
 		Ok(())
 	}
@@ -363,3 +371,39 @@ impl<'a> TransactionDoubleSpend<'a> {
 		Ok(())
 	}
 }
+
+pub struct TransactionReturnReplayProtection<'a> {
+	transaction: CanonTransaction<'a>,
+	consensus: &'a ConsensusParams,
+	height: u32,
+}
+
+lazy_static! {
+	pub static ref BITCOIN_CASH_RETURN_REPLAY_PROTECTION_SCRIPT: Bytes = Builder::default()
+		.return_bytes(b"Bitcoin: A Peer-to-Peer Electronic Cash System") // TODO: check that data.size() == 46
+		.into_bytes();
+}
+
+impl<'a> TransactionReturnReplayProtection<'a> {
+	fn new(transaction: CanonTransaction<'a>, consensus: &'a ConsensusParams, height: u32) -> Self {
+		TransactionReturnReplayProtection {
+			transaction: transaction,
+			consensus: consensus,
+			height: height,
+		}
+	}
+
+	fn check(&self) -> Result<(), TransactionError> {
+		if let ConsensusFork::BitcoinCash(fork_block) = self.consensus.fork {
+			// Transactions with such OP_RETURNs shall be considered valid again for block 530,001 and onwards
+			if self.height >= fork_block && self.height <= 530_000 {
+				if (*self.transaction).raw.outputs.iter()
+					.any(|out| out.script_pubkey == *BITCOIN_CASH_RETURN_REPLAY_PROTECTION_SCRIPT) {
+					return Err(TransactionError::ReturnReplayProtection)
+				}
+			}
+		}
+
+		Ok(())
+	}
+}

verification/src/error.rs

@@ -93,5 +93,7 @@ pub enum TransactionError {
 	UnspentTransactionWithTheSameHash,
 	/// Using output that is surely spent
 	UsingSpentOutput(H256, u32),
+	/// Transaction, protected using BitcoinCash OP_RETURN replay protection (REQ-6-1).
+	ReturnReplayProtection,
 }
 

verification/src/lib.rs

@@ -53,6 +53,8 @@
 
 extern crate time;
 #[macro_use]
+extern crate lazy_static;
+#[macro_use]
 extern crate log;
 extern crate parking_lot;
 extern crate rayon;