Test that we do not fail-backwards HTLCs that the remote on-chained
[rust-lightning] / src / ln / channelmonitor.rs
index e467772b1fa1628d4c795547073e944b720245c9..ded2a99dc37cf2933150d8537ec31ecfaddc073e 100644 (file)
@@ -48,6 +48,9 @@ pub enum ChannelMonitorUpdateErr {
 /// which we have revoked, allowing our counterparty to claim all funds in the channel!
 pub trait ManyChannelMonitor: Send + Sync {
        /// Adds or updates a monitor for the given `funding_txo`.
+       /// Implementor must also ensure that the funding_txo outpoint is registered with any relevant
+       /// ChainWatchInterfaces such that the provided monitor receives block_connected callbacks with
+       /// any spends of it.
        fn add_update_monitor(&self, funding_txo: OutPoint, monitor: ChannelMonitor) -> Result<(), ChannelMonitorUpdateErr>;
 }
 
@@ -60,6 +63,9 @@ pub trait ManyChannelMonitor: Send + Sync {
 /// If you're using this for local monitoring of your own channels, you probably want to use
 /// `OutPoint` as the key, which will give you a ManyChannelMonitor implementation.
 pub struct SimpleManyChannelMonitor<Key> {
+       #[cfg(test)] // Used in ChannelManager tests to manipulate channels directly
+       pub monitors: Mutex<HashMap<Key, ChannelMonitor>>,
+       #[cfg(not(test))]
        monitors: Mutex<HashMap<Key, ChannelMonitor>>,
        chain_monitor: Arc<ChainWatchInterface>,
        broadcaster: Arc<BroadcasterInterface>
@@ -69,7 +75,12 @@ impl<Key : Send + cmp::Eq + hash::Hash> ChainListener for SimpleManyChannelMonit
        fn block_connected(&self, _header: &BlockHeader, height: u32, txn_matched: &[&Transaction], _indexes_of_txn_matched: &[u32]) {
                let monitors = self.monitors.lock().unwrap();
                for monitor in monitors.values() {
-                       monitor.block_connected(txn_matched, height, &*self.broadcaster);
+                       let txn_outputs = monitor.block_connected(txn_matched, height, &*self.broadcaster);
+                       for (ref txid, ref outputs) in txn_outputs {
+                               for (idx, output) in outputs.iter().enumerate() {
+                                       self.chain_monitor.install_watch_outpoint((txid.clone(), idx as u32), &output.script_pubkey);
+                               }
+                       }
                }
        }
 
@@ -158,6 +169,7 @@ pub struct ChannelMonitor {
        key_storage: KeyStorage,
        delayed_payment_base_key: PublicKey,
        their_htlc_base_key: Option<PublicKey>,
+       their_delayed_payment_base_key: Option<PublicKey>,
        // first is the idx of the first of the two revocation points
        their_cur_revocation_points: Option<(u64, PublicKey, Option<PublicKey>)>,
 
@@ -199,6 +211,7 @@ impl Clone for ChannelMonitor {
                        key_storage: self.key_storage.clone(),
                        delayed_payment_base_key: self.delayed_payment_base_key.clone(),
                        their_htlc_base_key: self.their_htlc_base_key.clone(),
+                       their_delayed_payment_base_key: self.their_delayed_payment_base_key.clone(),
                        their_cur_revocation_points: self.their_cur_revocation_points.clone(),
 
                        our_to_self_delay: self.our_to_self_delay,
@@ -230,6 +243,7 @@ impl PartialEq for ChannelMonitor {
                        self.key_storage != other.key_storage ||
                        self.delayed_payment_base_key != other.delayed_payment_base_key ||
                        self.their_htlc_base_key != other.their_htlc_base_key ||
+                       self.their_delayed_payment_base_key != other.their_delayed_payment_base_key ||
                        self.their_cur_revocation_points != other.their_cur_revocation_points ||
                        self.our_to_self_delay != other.our_to_self_delay ||
                        self.their_to_self_delay != other.their_to_self_delay ||
@@ -266,6 +280,7 @@ impl ChannelMonitor {
                        },
                        delayed_payment_base_key: delayed_payment_base_key.clone(),
                        their_htlc_base_key: None,
+                       their_delayed_payment_base_key: None,
                        their_cur_revocation_points: None,
 
                        our_to_self_delay: our_to_self_delay,
@@ -464,13 +479,16 @@ impl ChannelMonitor {
        /// optional, without it this monitor cannot be used in an SPV client, but you may wish to
        /// avoid this (or call unset_funding_info) on a monitor you wish to send to a watchtower as it
        /// provides slightly better privacy.
+       /// It's the responsibility of the caller to register outpoint and script with passing the former
+       /// value as key to add_update_monitor.
        pub(super) fn set_funding_info(&mut self, funding_info: (OutPoint, Script)) {
-               //TODO: Need to register the given script here with a chain_monitor
                self.funding_txo = Some(funding_info);
        }
 
-       pub(super) fn set_their_htlc_base_key(&mut self, their_htlc_base_key: &PublicKey) {
+       /// We log these base keys at channel opening to being able to rebuild redeemscript in case of leaked revoked commit tx
+       pub(super) fn set_their_base_keys(&mut self, their_htlc_base_key: &PublicKey, their_delayed_payment_base_key: &PublicKey) {
                self.their_htlc_base_key = Some(their_htlc_base_key.clone());
+               self.their_delayed_payment_base_key = Some(their_delayed_payment_base_key.clone());
        }
 
        pub(super) fn set_their_to_self_delay(&mut self, their_to_self_delay: u16) {
@@ -522,6 +540,7 @@ impl ChannelMonitor {
 
                res.extend_from_slice(&self.delayed_payment_base_key.serialize());
                res.extend_from_slice(&self.their_htlc_base_key.as_ref().unwrap().serialize());
+               res.extend_from_slice(&self.their_delayed_payment_base_key.as_ref().unwrap().serialize());
 
                match self.their_cur_revocation_points {
                        Some((idx, pubkey, second_option)) => {
@@ -696,6 +715,7 @@ impl ChannelMonitor {
 
                let delayed_payment_base_key = unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33)));
                let their_htlc_base_key = Some(unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33))));
+               let their_delayed_payment_base_key = Some(unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33))));
 
                let their_cur_revocation_points = {
                        let first_idx = byte_utils::slice_to_be48(read_bytes!(6));
@@ -858,6 +878,7 @@ impl ChannelMonitor {
                        key_storage,
                        delayed_payment_base_key,
                        their_htlc_base_key,
+                       their_delayed_payment_base_key,
                        their_cur_revocation_points,
 
                        our_to_self_delay,
@@ -906,24 +927,25 @@ impl ChannelMonitor {
        /// Attempts to claim a remote commitment transaction's outputs using the revocation key and
        /// data in remote_claimable_outpoints. Will directly claim any HTLC outputs which expire at a
        /// height > height + CLTV_SHARED_CLAIM_BUFFER. In any case, will install monitoring for
-       /// HTLC-Success/HTLC-Timeout transactions, and claim them using the revocation key (if
-       /// applicable) as well.
-       fn check_spend_remote_transaction(&self, tx: &Transaction, height: u32) -> Vec<Transaction> {
+       /// HTLC-Success/HTLC-Timeout transactions.
+       fn check_spend_remote_transaction(&self, tx: &Transaction, height: u32) -> (Vec<Transaction>, (Sha256dHash, Vec<TxOut>)) {
                // Most secp and related errors trying to create keys means we have no hope of constructing
                // a spend transaction...so we return no transactions to broadcast
                let mut txn_to_broadcast = Vec::new();
+               let mut watch_outputs = Vec::new();
+
+               let commitment_txid = tx.txid(); //TODO: This is gonna be a performance bottleneck for watchtowers!
+               let per_commitment_option = self.remote_claimable_outpoints.get(&commitment_txid);
+
                macro_rules! ignore_error {
                        ( $thing : expr ) => {
                                match $thing {
                                        Ok(a) => a,
-                                       Err(_) => return txn_to_broadcast
+                                       Err(_) => return (txn_to_broadcast, (commitment_txid, watch_outputs))
                                }
                        };
                }
 
-               let commitment_txid = tx.txid(); //TODO: This is gonna be a performance bottleneck for watchtowers!
-               let per_commitment_option = self.remote_claimable_outpoints.get(&commitment_txid);
-
                let commitment_number = 0xffffffffffff - ((((tx.input[0].sequence as u64 & 0xffffff) << 3*8) | (tx.lock_time as u64 & 0xffffff)) ^ self.commitment_transaction_number_obscure_factor);
                if commitment_number >= self.get_min_seen_secret() {
                        let secret = self.get_secret(commitment_number).unwrap();
@@ -942,7 +964,7 @@ impl ChannelMonitor {
                        };
                        let delayed_key = ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, &PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key), &self.delayed_payment_base_key));
                        let a_htlc_key = match self.their_htlc_base_key {
-                               None => return txn_to_broadcast,
+                               None => return (txn_to_broadcast, (commitment_txid, watch_outputs)),
                                Some(their_htlc_base_key) => ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, &PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key), &their_htlc_base_key)),
                        };
 
@@ -1009,7 +1031,7 @@ impl ChannelMonitor {
                                        if htlc.transaction_output_index as usize >= tx.output.len() ||
                                                        tx.output[htlc.transaction_output_index as usize].value != htlc.amount_msat / 1000 ||
                                                        tx.output[htlc.transaction_output_index as usize].script_pubkey != expected_script.to_v0_p2wsh() {
-                                               return txn_to_broadcast; // Corrupted per_commitment_data, fuck this user
+                                               return (txn_to_broadcast, (commitment_txid, watch_outputs)); // Corrupted per_commitment_data, fuck this user
                                        }
                                        let input = TxIn {
                                                previous_output: BitcoinOutPoint {
@@ -1044,10 +1066,10 @@ impl ChannelMonitor {
 
                        if !inputs.is_empty() || !txn_to_broadcast.is_empty() { // ie we're confident this is actually ours
                                // We're definitely a remote commitment transaction!
-                               // TODO: Register all outputs in commitment_tx with the ChainWatchInterface!
+                               watch_outputs.append(&mut tx.output.clone());
                                self.remote_commitment_txn_on_chain.lock().unwrap().insert(commitment_txid, commitment_number);
                        }
-                       if inputs.is_empty() { return txn_to_broadcast; } // Nothing to be done...probably a false positive/local tx
+                       if inputs.is_empty() { return (txn_to_broadcast, (commitment_txid, watch_outputs)); } // Nothing to be done...probably a false positive/local tx
 
                        let outputs = vec!(TxOut {
                                script_pubkey: self.destination_script.clone(),
@@ -1077,7 +1099,7 @@ impl ChannelMonitor {
                        // already processed the block, resulting in the remote_commitment_txn_on_chain entry
                        // not being generated by the above conditional. Thus, to be safe, we go ahead and
                        // insert it here.
-                       // TODO: Register all outputs in commitment_tx with the ChainWatchInterface!
+                       watch_outputs.append(&mut tx.output.clone());
                        self.remote_commitment_txn_on_chain.lock().unwrap().insert(commitment_txid, commitment_number);
 
                        if let Some(revocation_points) = self.their_cur_revocation_points {
@@ -1098,7 +1120,7 @@ impl ChannelMonitor {
                                                },
                                        };
                                        let a_htlc_key = match self.their_htlc_base_key {
-                                               None => return txn_to_broadcast,
+                                               None => return (txn_to_broadcast, (commitment_txid, watch_outputs)),
                                                Some(their_htlc_base_key) => ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, revocation_point, &their_htlc_base_key)),
                                        };
 
@@ -1161,7 +1183,7 @@ impl ChannelMonitor {
                                                }
                                        }
 
-                                       if inputs.is_empty() { return txn_to_broadcast; } // Nothing to be done...probably a false positive/local tx
+                                       if inputs.is_empty() { return (txn_to_broadcast, (commitment_txid, watch_outputs)); } // Nothing to be done...probably a false positive/local tx
 
                                        let outputs = vec!(TxOut {
                                                script_pubkey: self.destination_script.clone(),
@@ -1185,11 +1207,90 @@ impl ChannelMonitor {
                                        txn_to_broadcast.push(spend_tx);
                                }
                        }
-               } else {
-                       //TODO: For each input check if its in our remote_commitment_txn_on_chain map!
                }
 
-               txn_to_broadcast
+               (txn_to_broadcast, (commitment_txid, watch_outputs))
+       }
+
+       /// Attempst to claim a remote HTLC-Success/HTLC-Timeout s outputs using the revocation key
+       fn check_spend_remote_htlc(&self, tx: &Transaction, commitment_number: u64) -> Option<Transaction> {
+               let htlc_txid = tx.txid(); //TODO: This is gonna be a performance bottleneck for watchtowers!
+
+               macro_rules! ignore_error {
+                       ( $thing : expr ) => {
+                               match $thing {
+                                       Ok(a) => a,
+                                       Err(_) => return None
+                               }
+                       };
+               }
+
+               let secret = ignore_error!(self.get_secret(commitment_number));
+               let per_commitment_key = ignore_error!(SecretKey::from_slice(&self.secp_ctx, &secret));
+               let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key);
+               let revocation_pubkey = match self.key_storage {
+                       KeyStorage::PrivMode { ref revocation_base_key, .. } => {
+                               ignore_error!(chan_utils::derive_public_revocation_key(&self.secp_ctx, &per_commitment_point, &PublicKey::from_secret_key(&self.secp_ctx, &revocation_base_key)))
+                       },
+                       KeyStorage::SigsMode { ref revocation_base_key, .. } => {
+                               ignore_error!(chan_utils::derive_public_revocation_key(&self.secp_ctx, &per_commitment_point, &revocation_base_key))
+                       },
+               };
+               let delayed_key = match self.their_delayed_payment_base_key {
+                       None => return None,
+                       Some(their_delayed_payment_base_key) => ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, &per_commitment_point, &their_delayed_payment_base_key)),
+               };
+               let redeemscript = chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.their_to_self_delay.unwrap(), &delayed_key);
+               let revokeable_p2wsh = redeemscript.to_v0_p2wsh();
+
+               let mut inputs = Vec::new();
+               let mut amount = 0;
+
+               if tx.output[0].script_pubkey == revokeable_p2wsh { //HTLC transactions have one txin, one txout
+                       inputs.push(TxIn {
+                               previous_output: BitcoinOutPoint {
+                                       txid: htlc_txid,
+                                       vout: 0,
+                               },
+                               script_sig: Script::new(),
+                               sequence: 0xfffffffd,
+                               witness: Vec::new(),
+                       });
+                       amount = tx.output[0].value;
+               }
+
+               if !inputs.is_empty() {
+                       let outputs = vec!(TxOut {
+                               script_pubkey: self.destination_script.clone(),
+                               value: amount, //TODO: - fee
+                       });
+
+                       let mut spend_tx = Transaction {
+                               version: 2,
+                               lock_time: 0,
+                               input: inputs,
+                               output: outputs,
+                       };
+
+                       let sighash_parts = bip143::SighashComponents::new(&spend_tx);
+
+                       let sig = match self.key_storage {
+                               KeyStorage::PrivMode { ref revocation_base_key, .. } => {
+                                       let sighash = ignore_error!(Message::from_slice(&sighash_parts.sighash_all(&spend_tx.input[0], &redeemscript, amount)[..]));
+                                       let revocation_key = ignore_error!(chan_utils::derive_private_revocation_key(&self.secp_ctx, &per_commitment_key, &revocation_base_key));
+                                       self.secp_ctx.sign(&sighash, &revocation_key)
+                               }
+                               KeyStorage::SigsMode { .. } => {
+                                       unimplemented!();
+                               }
+                       };
+                       spend_tx.input[0].witness.push(sig.serialize_der(&self.secp_ctx).to_vec());
+                       spend_tx.input[0].witness[0].push(SigHashType::All as u8);
+                       spend_tx.input[0].witness.push(vec!(1));
+                       spend_tx.input[0].witness.push(redeemscript.into_bytes());
+
+                       Some(spend_tx)
+               } else { None }
        }
 
        fn broadcast_by_local_state(&self, local_tx: &LocalSignedTx) -> Vec<Transaction> {
@@ -1250,18 +1351,36 @@ impl ChannelMonitor {
                Vec::new()
        }
 
-       fn block_connected(&self, txn_matched: &[&Transaction], height: u32, broadcaster: &BroadcasterInterface) {
+       fn block_connected(&self, txn_matched: &[&Transaction], height: u32, broadcaster: &BroadcasterInterface)-> Vec<(Sha256dHash, Vec<TxOut>)> {
+               let mut watch_outputs = Vec::new();
                for tx in txn_matched {
-                       for txin in tx.input.iter() {
-                               if self.funding_txo.is_none() || (txin.previous_output.txid == self.funding_txo.as_ref().unwrap().0.txid && txin.previous_output.vout == self.funding_txo.as_ref().unwrap().0.index as u32) {
-                                       let mut txn = self.check_spend_remote_transaction(tx, height);
+                       if tx.input.len() == 1 {
+                               // Assuming our keys were not leaked (in which case we're screwed no matter what),
+                               // commitment transactions and HTLC transactions will all only ever have one input,
+                               // which is an easy way to filter out any potential non-matching txn for lazy
+                               // filters.
+                               let prevout = &tx.input[0].previous_output;
+                               let mut txn: Vec<Transaction> = Vec::new();
+                               if self.funding_txo.is_none() || (prevout.txid == self.funding_txo.as_ref().unwrap().0.txid && prevout.vout == self.funding_txo.as_ref().unwrap().0.index as u32) {
+                                       let (remote_txn, new_outputs) = self.check_spend_remote_transaction(tx, height);
+                                       txn = remote_txn;
+                                       if !new_outputs.1.is_empty() {
+                                               watch_outputs.push(new_outputs);
+                                       }
                                        if txn.is_empty() {
                                                txn = self.check_spend_local_transaction(tx, height);
                                        }
-                                       for tx in txn.iter() {
-                                               broadcaster.broadcast_transaction(tx);
+                               } else {
+                                       let remote_commitment_txn_on_chain = self.remote_commitment_txn_on_chain.lock().unwrap();
+                                       if let Some(commitment_number) = remote_commitment_txn_on_chain.get(&prevout.txid) {
+                                               if let Some(tx) = self.check_spend_remote_htlc(tx, *commitment_number) {
+                                                       txn.push(tx);
+                                               }
                                        }
                                }
+                               for tx in txn.iter() {
+                                       broadcaster.broadcast_transaction(tx);
+                               }
                        }
                }
                if let Some(ref cur_local_tx) = self.current_local_signed_commitment_tx {
@@ -1281,6 +1400,7 @@ impl ChannelMonitor {
                                }
                        }
                }
+               watch_outputs
        }
 
        pub fn would_broadcast_at_height(&self, height: u32) -> bool {