Merge pull request #571 from ariard/2020-04-fix-minimalif

Enforce MINIMALIF-compliant witnesses

Author: TheBlueMatt

lightning/src/chain/keysinterface.rs

@@ -54,7 +54,7 @@ pub enum SpendableOutputDescriptor {
 	/// The private key which should be used to sign the transaction is provided, as well as the
 	/// full witness redeemScript which is hashed in the output script_pubkey.
 	/// The witness in the spending input should be:
-	/// <BIP 143 signature generated with the given key> <one zero byte aka OP_0>
+	/// <BIP 143 signature generated with the given key> <empty vector> (MINIMALIF standard rule)
 	/// <witness_script as provided>
 	/// Note that the nSequence field in the input must be set to_self_delay (which corresponds to
 	/// the transaction not being broadcastable until at least to_self_delay blocks after the input

lightning/src/ln/functional_tests.rs

@@ -4079,7 +4079,7 @@ macro_rules! check_spendable_outputs {
 									let local_delaysig = secp_ctx.sign(&sighash, key);
 									spend_tx.input[0].witness.push(local_delaysig.serialize_der().to_vec());
 									spend_tx.input[0].witness[0].push(SigHashType::All as u8);
-									spend_tx.input[0].witness.push(vec!(0));
+									spend_tx.input[0].witness.push(vec!());
 									spend_tx.input[0].witness.push(witness_script.clone().into_bytes());
 									txn.push(spend_tx);
 								},

lightning/src/ln/onchaintx.rs

@@ -470,7 +470,7 @@ impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 					if let &Some(preimage) = preimage {
 						bumped_tx.input[i].witness.push(preimage.clone().0.to_vec());
 					} else {
-						bumped_tx.input[i].witness.push(vec![0]);
+						bumped_tx.input[i].witness.push(vec![]);
 					}
 					bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 					log_trace!(self, "Going to broadcast Claim Transaction {} claiming remote {} htlc output {} from {} with new feerate {}...", bumped_tx.txid(), if preimage.is_some() { "offered" } else { "received" }, outp.vout, outp.txid, new_feerate);