Move script too long check into is_unsupported_shutdown_script

Author: galderz

lightning/src/ln/channel.rs

@@ -691,10 +691,12 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			return Err(ChannelError::Close("Insufficient funding amount for initial commitment".to_owned()));
 		}
 
+		let is_outbound = false;
+
 		let counterparty_shutdown_scriptpubkey = if their_features.supports_upfront_shutdown_script() {
 			match &msg.shutdown_scriptpubkey {
 				&OptionalField::Present(ref script) => {
-					if is_unsupported_shutdown_script(&their_features, script) {
+					if is_unsupported_shutdown_script(&their_features, script, is_outbound) {
 						return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided a non-accepted scriptpubkey format. script: ({})", script.to_bytes().to_hex())));
 					}
 
@@ -772,7 +774,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			channel_transaction_parameters: ChannelTransactionParameters {
 				holder_pubkeys: pubkeys,
 				holder_selected_contest_delay: config.own_channel_config.our_to_self_delay,
-				is_outbound_from_holder: false,
+				is_outbound_from_holder: is_outbound,
 				counterparty_parameters: Some(CounterpartyChannelTransactionParameters {
 					selected_contest_delay: msg.to_self_delay,
 					pubkeys: counterparty_pubkeys,
@@ -1390,7 +1392,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		let counterparty_shutdown_scriptpubkey = if their_features.supports_upfront_shutdown_script() {
 			match &msg.shutdown_scriptpubkey {
 				&OptionalField::Present(ref script) => {
-					if is_unsupported_shutdown_script(&their_features, script) {
+					if is_unsupported_shutdown_script(&their_features, script, self.is_outbound()) {
 						return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided a non-accepted scriptpubkey format. script: ({})", script.to_bytes().to_hex())));
 					}
 
@@ -2903,15 +2905,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		}
 		assert_eq!(self.channel_state & ChannelState::ShutdownComplete as u32, 0);
 
-		// BOLT 2 says we must only send a scriptpubkey of certain standard forms,
-		// which for a a BIP-141-compliant witness program is at max 42 bytes in length.
-		// So don't let the remote peer feed us some super fee-heavy script.
-		if self.is_outbound() && msg.scriptpubkey.len() > 42 {
-			return Err(ChannelError::Close(format!("Got counterparty shutdown_scriptpubkey ({}) of absurd length from remote peer", msg.scriptpubkey.to_bytes().to_hex())));
-		}
-
-		//Check counterparty_shutdown_scriptpubkey form as BOLT says we must
-		if is_unsupported_shutdown_script(&their_features, &msg.scriptpubkey) {
+		if is_unsupported_shutdown_script(&their_features, &msg.scriptpubkey, self.is_outbound()) {
 			return Err(ChannelError::Close(format!("Got a nonstandard scriptpubkey ({}) from remote peer", msg.scriptpubkey.to_bytes().to_hex())));
 		}
 
@@ -4019,8 +4013,12 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	}
 }
 
-fn is_unsupported_shutdown_script(their_features: &InitFeatures, scriptpubkey: &Script) -> bool {
-	return is_unsupported_witness_shutdown_script(their_features, scriptpubkey) && !scriptpubkey.is_p2pkh() && !scriptpubkey.is_p2sh() && !scriptpubkey.is_v0_p2wpkh() && !scriptpubkey.is_v0_p2wsh()
+fn is_unsupported_shutdown_script(their_features: &InitFeatures, scriptpubkey: &Script, is_outbound: bool) -> bool {
+	// BOLT 2 says we must only send a scriptpubkey of certain standard forms,
+	// which for a a BIP-141-compliant witness program is at max 42 bytes in length.
+	// So don't let the remote peer feed us some super fee-heavy script.
+	let is_script_too_long = is_outbound && scriptpubkey.len() > 42;
+	return is_script_too_long || (is_unsupported_witness_shutdown_script(their_features, scriptpubkey) && !scriptpubkey.is_p2pkh() && !scriptpubkey.is_p2sh() && !scriptpubkey.is_v0_p2wpkh() && !scriptpubkey.is_v0_p2wsh())
 }
 
 fn is_unsupported_witness_shutdown_script(their_features: &InitFeatures, scriptpubkey: &Script) -> bool {