Merge pull request #163 from ariard/claim_revoked_htlc_tx
[rust-lightning] / src / ln / channelmonitor.rs
index 39146daa9b2d96e6f93f5251c76e0f77353e72fb..6de0a63609ac6a4c8333796ad6da639f0c0760fe 100644 (file)
@@ -166,6 +166,7 @@ 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>)>,
 
@@ -207,6 +208,7 @@ 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,
@@ -238,6 +240,7 @@ 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 ||
@@ -274,6 +277,7 @@ 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,
@@ -478,8 +482,10 @@ impl ChannelMonitor {
                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) {
@@ -531,6 +537,7 @@ 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)) => {
@@ -705,6 +712,7 @@ 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));
@@ -867,6 +875,7 @@ 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,
@@ -915,8 +924,7 @@ 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.
+       /// 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
@@ -1196,13 +1204,97 @@ 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, (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) -> Vec<Transaction> {
+               let mut txn_to_broadcast = Vec::new();
+
+               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 txn_to_broadcast
+                               }
+                       };
+               }
+
+               let secret = self.get_secret(commitment_number).unwrap();
+               let per_commitment_key = ignore_error!(SecretKey::from_slice(&self.secp_ctx, &secret));
+               let revocation_pubkey = match self.key_storage {
+                       KeyStorage::PrivMode { ref revocation_base_key, .. } => {
+                               let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_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, .. } => {
+                               let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_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 txn_to_broadcast,
+                       Some(their_delayed_payment_base_key) => ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, &PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key), &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());
+
+                       txn_to_broadcast.push(spend_tx);
+               }
+               txn_to_broadcast
+       }
+
        fn broadcast_by_local_state(&self, local_tx: &LocalSignedTx) -> Vec<Transaction> {
                let mut res = Vec::with_capacity(local_tx.htlc_outputs.len());
 
@@ -1264,19 +1356,26 @@ impl ChannelMonitor {
        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 {
+                       let mut txn: Vec<Transaction> = Vec::new();
                        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, new_outputs) = self.check_spend_remote_transaction(tx, height);
+                                       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();
+                                       for commitment_number in remote_commitment_txn_on_chain.get(&txin.previous_output.txid) {
+                                               txn =  self.check_spend_remote_htlc(tx, *commitment_number);
                                        }
                                }
+                               for tx in txn.iter() {
+                                       broadcaster.broadcast_transaction(tx);
+                               }
                        }
                }
                if let Some(ref cur_local_tx) = self.current_local_signed_commitment_tx {