Use usize for transaction-position-in-block values

We use them largely as indexes into a Vec<Transaction> so there's
little reason for them to be u32s. Instead, use them as usize
everywhere.

We also take this opportunity to add range checks before
short_channel_id calculation, as we could otherwise end up with a
bogus short_channel_id due to an output index out of range.

Author: TheBlueMatt

lightning/src/chain/chaininterface.rs

@@ -55,7 +55,7 @@ pub trait ChainWatchInterface: Sync + Send {
 
 	/// Gets the list of transaction indices within a given block that the ChainWatchInterface is
 	/// watching for.
-	fn filter_block(&self, block: &Block) -> Vec<u32>;
+	fn filter_block(&self, block: &Block) -> Vec<usize>;
 
 	/// Returns a usize that changes when the ChainWatchInterface's watched data is modified.
 	/// Users of `filter_block` should pre-save a copy of `reentered`'s return value and use it to
@@ -86,7 +86,7 @@ pub trait ChainListener: Sync + Send {
 	///
 	/// This also means those counting confirmations using block_connected callbacks should watch
 	/// for duplicate headers and not count them towards confirmations!
-	fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]);
+	fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[usize]);
 	/// Notifies a listener that a block was disconnected.
 	/// Unlike block_connected, this *must* never be called twice for the same disconnect event.
 	/// Height must be the one of the block which was disconnected (not new height of the best chain)
@@ -280,7 +280,7 @@ impl<'a, CL: Deref<Target = ChainListener + 'a> + 'a, C: Deref> BlockNotifier<'a
 			let matched_indexes = self.chain_monitor.filter_block(block);
 			let mut matched_txn = Vec::new();
 			for index in matched_indexes.iter() {
-				matched_txn.push(&block.txdata[*index as usize]);
+				matched_txn.push(&block.txdata[*index]);
 			}
 			reentered = self.block_connected_checked(&block.header, height, matched_txn.as_slice(), matched_indexes.as_slice());
 		}
@@ -292,7 +292,7 @@ impl<'a, CL: Deref<Target = ChainListener + 'a> + 'a, C: Deref> BlockNotifier<'a
 	/// Returns true if notified listeners registered additional watch data (implying that the
 	/// block must be re-scanned and this function called again prior to further block_connected
 	/// calls, see ChainListener::block_connected for more info).
-	pub fn block_connected_checked(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) -> bool {
+	pub fn block_connected_checked(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[usize]) -> bool {
 		let last_seen = self.chain_monitor.reentered();
 
 		let listeners = self.listeners.lock().unwrap();
@@ -361,13 +361,13 @@ impl ChainWatchInterface for ChainWatchInterfaceUtil {
 		Err(ChainError::NotSupported)
 	}
 
-	fn filter_block(&self, block: &Block) -> Vec<u32> {
+	fn filter_block(&self, block: &Block) -> Vec<usize> {
 		let mut matched_index = Vec::new();
 		{
 			let watched = self.watched.lock().unwrap();
 			for (index, transaction) in block.txdata.iter().enumerate() {
 				if self.does_match_tx_unguarded(transaction, &watched) {
-					matched_index.push(index as u32);
+					matched_index.push(index);
 				}
 			}
 		}

lightning/src/ln/channel.rs

@@ -3176,7 +3176,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	///
 	/// May return some HTLCs (and their payment_hash) which have timed out and should be failed
 	/// back.
-	pub fn block_connected(&mut self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) -> Result<(Option<msgs::FundingLocked>, Vec<(HTLCSource, PaymentHash)>), msgs::ErrorMessage> {
+	pub fn block_connected(&mut self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[usize]) -> Result<(Option<msgs::FundingLocked>, Vec<(HTLCSource, PaymentHash)>), msgs::ErrorMessage> {
 		let mut timed_out_htlcs = Vec::new();
 		self.holding_cell_htlc_updates.retain(|htlc_update| {
 			match htlc_update {
@@ -3216,6 +3216,11 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 							channel_id: self.channel_id(),
 							data: "funding tx had wrong script/value".to_owned()
 						});
+					} else if txo_idx > 0xff_ff {
+						return Err(msgs::ErrorMessage {
+							channel_id: self.channel_id(),
+							data: "funding tx output was > 2**16 which makes short_channel_id impossible to calculate".to_owned()
+						});
 					} else {
 						if self.channel_outbound {
 							for input in tx.input.iter() {
@@ -3227,6 +3232,9 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 								}
 							}
 						}
+						if height > 0xff_ff_ff || (*index_in_block) > 0xff_ff_ff {
+							panic!("Block was bogus - either height 16 million or had > 16 million transactions");
+						}
 						self.funding_tx_confirmations = 1;
 						self.short_channel_id = Some(((height as u64)          << (5*8)) |
 						                             ((*index_in_block as u64) << (2*8)) |

lightning/src/ln/channelmanager.rs

@@ -2956,7 +2956,7 @@ impl<ChanSigner: ChannelKeys, M: Deref + Sync + Send, T: Deref + Sync + Send, K:
         F::Target: FeeEstimator,
 				L::Target: Logger,
 {
-	fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) {
+	fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[usize]) {
 		let header_hash = header.bitcoin_hash();
 		log_trace!(self.logger, "Block {} at height {} connected with {} txn matched", header_hash, height, txn_matched.len());
 		let _ = self.total_consistency_lock.read().unwrap();

lightning/src/ln/channelmonitor.rs

@@ -183,7 +183,7 @@ impl<Key : Send + cmp::Eq + hash::Hash, ChanSigner: ChannelKeys, T: Deref + Sync
 	      L::Target: Logger,
         C::Target: ChainWatchInterface,
 {
-	fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], _indexes_of_txn_matched: &[u32]) {
+	fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], _indexes_of_txn_matched: &[usize]) {
 		let block_hash = header.bitcoin_hash();
 		{
 			let mut monitors = self.monitors.lock().unwrap();

lightning/src/ln/functional_test_utils.rs

@@ -41,7 +41,7 @@ pub const CHAN_CONFIRM_DEPTH: u32 = 100;
 pub fn confirm_transaction<'a, 'b: 'a>(notifier: &'a chaininterface::BlockNotifierRef<'b, &chaininterface::ChainWatchInterfaceUtil>, chain: &chaininterface::ChainWatchInterfaceUtil, tx: &Transaction, chan_id: u32) {
 	assert!(chain.does_match_tx(tx));
 	let mut header = BlockHeader { version: 0x20000000, prev_blockhash: Default::default(), merkle_root: Default::default(), time: 42, bits: 42, nonce: 42 };
-	notifier.block_connected_checked(&header, 1, &[tx; 1], &[chan_id; 1]);
+	notifier.block_connected_checked(&header, 1, &[tx; 1], &[chan_id as usize; 1]);
 	for i in 2..CHAN_CONFIRM_DEPTH {
 		header = BlockHeader { version: 0x20000000, prev_blockhash: header.bitcoin_hash(), merkle_root: Default::default(), time: 42, bits: 42, nonce: 42 };
 		notifier.block_connected_checked(&header, i, &vec![], &[0; 0]);

lightning/src/ln/functional_tests.rs

@@ -410,10 +410,10 @@ fn test_1_conf_open() {
 	assert!(nodes[1].chain_monitor.does_match_tx(&tx));
 
 	let header = BlockHeader { version: 0x20000000, prev_blockhash: Default::default(), merkle_root: Default::default(), time: 42, bits: 42, nonce: 42 };
-	nodes[1].block_notifier.block_connected_checked(&header, 1, &[&tx; 1], &[tx.version; 1]);
+	nodes[1].block_notifier.block_connected_checked(&header, 1, &[&tx; 1], &[tx.version as usize; 1]);
 	nodes[0].node.handle_funding_locked(&nodes[1].node.get_our_node_id(), &get_event_msg!(nodes[1], MessageSendEvent::SendFundingLocked, nodes[0].node.get_our_node_id()));
 
-	nodes[0].block_notifier.block_connected_checked(&header, 1, &[&tx; 1], &[tx.version; 1]);
+	nodes[0].block_notifier.block_connected_checked(&header, 1, &[&tx; 1], &[tx.version as usize; 1]);
 	let (funding_locked, _) = create_chan_between_nodes_with_value_confirm_second(&nodes[1], &nodes[0]);
 	let (announcement, as_update, bs_update) = create_chan_between_nodes_with_value_b(&nodes[0], &nodes[1], &funding_locked);
 

lightning/src/util/test_utils.rs

@@ -371,7 +371,7 @@ impl ChainWatchInterface for TestChainWatcher {
 	fn install_watch_tx(&self, _txid: &Txid, _script_pub_key: &Script) { }
 	fn install_watch_outpoint(&self, _outpoint: (Txid, u32), _out_script: &Script) { }
 	fn watch_all_txn(&self) { }
-	fn filter_block<'a>(&self, _block: &'a Block) -> Vec<u32> {
+	fn filter_block<'a>(&self, _block: &'a Block) -> Vec<usize> {
 		Vec::new()
 	}
 	fn reentered(&self) -> usize { 0 }