Provide remote channel public keys to signer
[rust-lightning] / lightning / src / ln / channel.rs
index 1917ef5285eeabb7ddd90e2bcb5307f2df64ad9d..a9a8876404bd410cd30821230ea6f786dee71cf9 100644 (file)
@@ -15,11 +15,12 @@ use secp256k1::key::{PublicKey,SecretKey};
 use secp256k1::{Secp256k1,Signature};
 use secp256k1;
 
+use ln::features::{ChannelFeatures, InitFeatures};
 use ln::msgs;
-use ln::msgs::{DecodeError, OptionalField, LocalFeatures, DataLossProtect};
+use ln::msgs::{DecodeError, OptionalField, DataLossProtect};
 use ln::channelmonitor::ChannelMonitor;
 use ln::channelmanager::{PendingHTLCStatus, HTLCSource, HTLCFailReason, HTLCFailureMsg, PendingForwardHTLCInfo, RAACommitmentOrder, PaymentPreimage, PaymentHash, BREAKDOWN_TIMEOUT, MAX_LOCAL_BREAKDOWN_TIMEOUT};
-use ln::chan_utils::{LocalCommitmentTransaction,TxCreationKeys,HTLCOutputInCommitment,HTLC_SUCCESS_TX_WEIGHT,HTLC_TIMEOUT_TX_WEIGHT};
+use ln::chan_utils::{LocalCommitmentTransaction, TxCreationKeys, HTLCOutputInCommitment, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT, make_funding_redeemscript, ChannelPublicKeys};
 use ln::chan_utils;
 use chain::chaininterface::{FeeEstimator,ConfirmationTarget};
 use chain::transaction::OutPoint;
@@ -543,8 +544,16 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
        /// Creates a new channel from a remote sides' request for one.
        /// Assumes chain_hash has already been checked and corresponds with what we expect!
-       pub fn new_from_req(fee_estimator: &FeeEstimator, keys_provider: &Arc<KeysInterface<ChanKeySigner = ChanSigner>>, their_node_id: PublicKey, their_local_features: LocalFeatures, msg: &msgs::OpenChannel, user_id: u64, logger: Arc<Logger>, config: &UserConfig) -> Result<Channel<ChanSigner>, ChannelError> {
-               let chan_keys = keys_provider.get_channel_keys(true);
+       pub fn new_from_req(fee_estimator: &FeeEstimator, keys_provider: &Arc<KeysInterface<ChanKeySigner = ChanSigner>>, their_node_id: PublicKey, their_features: InitFeatures, msg: &msgs::OpenChannel, user_id: u64, logger: Arc<Logger>, config: &UserConfig) -> Result<Channel<ChanSigner>, ChannelError> {
+               let mut chan_keys = keys_provider.get_channel_keys(true);
+               let channel_pubkeys = ChannelPublicKeys {
+                       funding_pubkey: msg.funding_pubkey,
+                       revocation_basepoint: msg.revocation_basepoint,
+                       payment_basepoint: msg.payment_basepoint,
+                       delayed_payment_basepoint: msg.delayed_payment_basepoint,
+                       htlc_basepoint: msg.htlc_basepoint
+               };
+               chan_keys.set_remote_channel_pubkeys(&channel_pubkeys);
                let mut local_config = (*config).channel_options.clone();
 
                if config.own_channel_config.our_to_self_delay < BREAKDOWN_TIMEOUT {
@@ -648,7 +657,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
                                                          chan_keys.htlc_base_key(), chan_keys.payment_base_key(), &keys_provider.get_shutdown_pubkey(), config.own_channel_config.our_to_self_delay,
                                                          keys_provider.get_destination_script(), logger.clone());
 
-               let their_shutdown_scriptpubkey = if their_local_features.supports_upfront_shutdown_script() {
+               let their_shutdown_scriptpubkey = if their_features.supports_upfront_shutdown_script() {
                        match &msg.shutdown_scriptpubkey {
                                &OptionalField::Present(ref script) => {
                                        // Peer is signaling upfront_shutdown and has provided a non-accepted scriptpubkey format. We enforce it while receiving shutdown msg
@@ -1110,16 +1119,9 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
        /// pays to get_funding_redeemscript().to_v0_p2wsh()).
        /// Panics if called before accept_channel/new_from_req
        pub fn get_funding_redeemscript(&self) -> Script {
-               let builder = Builder::new().push_opcode(opcodes::all::OP_PUSHNUM_2);
-               let our_funding_key = PublicKey::from_secret_key(&self.secp_ctx, self.local_keys.funding_key()).serialize();
-               let their_funding_key = self.their_funding_pubkey.expect("get_funding_redeemscript only allowed after accept_channel").serialize();
-               if our_funding_key[..] < their_funding_key[..] {
-                       builder.push_slice(&our_funding_key)
-                               .push_slice(&their_funding_key)
-               } else {
-                       builder.push_slice(&their_funding_key)
-                               .push_slice(&our_funding_key)
-               }.push_opcode(opcodes::all::OP_PUSHNUM_2).push_opcode(opcodes::all::OP_CHECKMULTISIG).into_script()
+               let our_funding_key = PublicKey::from_secret_key(&self.secp_ctx, self.local_keys.funding_key());
+               let their_funding_key = self.their_funding_pubkey.expect("get_funding_redeemscript only allowed after accept_channel");
+               make_funding_redeemscript(&our_funding_key, &their_funding_key)
        }
 
        /// Builds the htlc-success or htlc-timeout transaction which spends a given HTLC output
@@ -1129,56 +1131,6 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
                chan_utils::build_htlc_transaction(prev_hash, feerate_per_kw, if local { self.their_to_self_delay } else { self.our_to_self_delay }, htlc, &keys.a_delayed_payment_key, &keys.revocation_key)
        }
 
-       fn create_htlc_tx_signature(&self, tx: &Transaction, htlc: &HTLCOutputInCommitment, keys: &TxCreationKeys) -> Result<(Script, Signature, bool), ChannelError> {
-               if tx.input.len() != 1 {
-                       panic!("Tried to sign HTLC transaction that had input count != 1!");
-               }
-
-               let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys);
-
-               let our_htlc_key = secp_check!(chan_utils::derive_private_key(&self.secp_ctx, &keys.per_commitment_point, self.local_keys.htlc_base_key()), "Derived invalid key, peer is maliciously selecting parameters");
-               let sighash = hash_to_message!(&bip143::SighashComponents::new(&tx).sighash_all(&tx.input[0], &htlc_redeemscript, htlc.amount_msat / 1000)[..]);
-               let is_local_tx = PublicKey::from_secret_key(&self.secp_ctx, &our_htlc_key) == keys.a_htlc_key;
-               Ok((htlc_redeemscript, self.secp_ctx.sign(&sighash, &our_htlc_key), is_local_tx))
-       }
-
-       #[cfg(test)]
-       /// Signs a transaction created by build_htlc_transaction. If the transaction is an
-       /// HTLC-Success transaction (ie htlc.offered is false), preimage must be set!
-       /// TODO: Make this a chan_utils, use it in channelmonitor and tests, cause its unused now
-       fn sign_htlc_transaction(&self, tx: &mut Transaction, their_sig: &Signature, preimage: &Option<PaymentPreimage>, htlc: &HTLCOutputInCommitment, keys: &TxCreationKeys) -> Result<Signature, ChannelError> {
-               if tx.input.len() != 1 {
-                       panic!("Tried to sign HTLC transaction that had input count != 1!");
-               }
-               if tx.input[0].witness.len() != 0 {
-                       panic!("Tried to re-sign HTLC transaction");
-               }
-
-               let (htlc_redeemscript, our_sig, local_tx) = self.create_htlc_tx_signature(tx, htlc, keys)?;
-
-               tx.input[0].witness.push(Vec::new()); // First is the multisig dummy
-
-               if local_tx { // b, then a
-                       tx.input[0].witness.push(their_sig.serialize_der().to_vec());
-                       tx.input[0].witness.push(our_sig.serialize_der().to_vec());
-               } else {
-                       tx.input[0].witness.push(our_sig.serialize_der().to_vec());
-                       tx.input[0].witness.push(their_sig.serialize_der().to_vec());
-               }
-               tx.input[0].witness[1].push(SigHashType::All as u8);
-               tx.input[0].witness[2].push(SigHashType::All as u8);
-
-               if htlc.offered {
-                       tx.input[0].witness.push(Vec::new());
-               } else {
-                       tx.input[0].witness.push(preimage.unwrap().0.to_vec());
-               }
-
-               tx.input[0].witness.push(htlc_redeemscript.into_bytes());
-
-               Ok(our_sig)
-       }
-
        /// Per HTLC, only one get_update_fail_htlc or get_update_fulfill_htlc call may be made.
        /// In such cases we debug_assert!(false) and return an IgnoreError. Thus, will always return
        /// Ok(_) if debug assertions are turned on and preconditions are met.
@@ -1356,7 +1308,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
        // Message handlers:
 
-       pub fn accept_channel(&mut self, msg: &msgs::AcceptChannel, config: &UserConfig, their_local_features: LocalFeatures) -> Result<(), ChannelError> {
+       pub fn accept_channel(&mut self, msg: &msgs::AcceptChannel, config: &UserConfig, their_features: InitFeatures) -> Result<(), ChannelError> {
                // Check sanity of message fields:
                if !self.channel_outbound {
                        return Err(ChannelError::Close("Got an accept_channel message from an inbound peer"));
@@ -1415,7 +1367,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
                        return Err(ChannelError::Close("We consider the minimum depth to be unreasonably large"));
                }
 
-               let their_shutdown_scriptpubkey = if their_local_features.supports_upfront_shutdown_script() {
+               let their_shutdown_scriptpubkey = if their_features.supports_upfront_shutdown_script() {
                        match &msg.shutdown_scriptpubkey {
                                &OptionalField::Present(ref script) => {
                                        // Peer is signaling upfront_shutdown and has provided a non-accepted scriptpubkey format. We enforce it while receiving shutdown msg
@@ -1456,6 +1408,14 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
                self.channel_monitor.set_basic_channel_info(&msg.htlc_basepoint, &msg.delayed_payment_basepoint, msg.to_self_delay, funding_redeemscript, self.channel_value_satoshis, obscure_factor);
 
                self.channel_state = ChannelState::OurInitSent as u32 | ChannelState::TheirInitSent as u32;
+               let channel_pubkeys = ChannelPublicKeys {
+                       funding_pubkey: msg.funding_pubkey,
+                       revocation_basepoint: msg.revocation_basepoint,
+                       payment_basepoint: msg.payment_basepoint,
+                       delayed_payment_basepoint: msg.delayed_payment_basepoint,
+                       htlc_basepoint: msg.htlc_basepoint
+               };
+               self.local_keys.set_remote_channel_pubkeys(&channel_pubkeys);
 
                Ok(())
        }
@@ -1474,7 +1434,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
                let remote_keys = self.build_remote_transaction_keys()?;
                let remote_initial_commitment_tx = self.build_commitment_transaction(self.cur_remote_commitment_transaction_number, &remote_keys, false, false, self.feerate_per_kw).0;
-               let remote_signature = self.local_keys.sign_remote_commitment(self.channel_value_satoshis, &self.get_funding_redeemscript(), self.feerate_per_kw, &remote_initial_commitment_tx, &remote_keys, &Vec::new(), self.our_to_self_delay, &self.secp_ctx)
+               let remote_signature = self.local_keys.sign_remote_commitment(self.channel_value_satoshis, self.feerate_per_kw, &remote_initial_commitment_tx, &remote_keys, &Vec::new(), self.our_to_self_delay, &self.secp_ctx)
                                .map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed"))?.0;
 
                // We sign the "remote" commitment transaction, allowing them to broadcast the tx if they wish.
@@ -1822,8 +1782,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
                                log_trace!(self, "Checking HTLC tx signature {} by key {} against tx {} with redeemscript {}", log_bytes!(msg.htlc_signatures[idx].serialize_compact()[..]), log_bytes!(local_keys.b_htlc_key.serialize()), encode::serialize_hex(&htlc_tx), encode::serialize_hex(&htlc_redeemscript));
                                let htlc_sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, htlc.amount_msat / 1000)[..]);
                                secp_check!(self.secp_ctx.verify(&htlc_sighash, &msg.htlc_signatures[idx], &local_keys.b_htlc_key), "Invalid HTLC tx signature from peer");
-                               let htlc_sig = self.create_htlc_tx_signature(&htlc_tx, &htlc, &local_keys)?.1;
-                               htlcs_and_sigs.push((htlc, Some((msg.htlc_signatures[idx], htlc_sig)), source));
+                               htlcs_and_sigs.push((htlc, Some(msg.htlc_signatures[idx]), source));
                        } else {
                                htlcs_and_sigs.push((htlc, None, source));
                        }
@@ -2695,6 +2654,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
                self.channel_state |= ChannelState::LocalShutdownSent as u32;
                self.channel_update_count += 1;
+
                Ok((our_shutdown, self.maybe_propose_first_closing_signed(fee_estimator), dropped_outbound_htlcs))
        }
 
@@ -3201,7 +3161,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
        fn get_outbound_funding_created_signature(&mut self) -> Result<(Signature, Transaction), ChannelError> {
                let remote_keys = self.build_remote_transaction_keys()?;
                let remote_initial_commitment_tx = self.build_commitment_transaction(self.cur_remote_commitment_transaction_number, &remote_keys, false, false, self.feerate_per_kw).0;
-               Ok((self.local_keys.sign_remote_commitment(self.channel_value_satoshis, &self.get_funding_redeemscript(), self.feerate_per_kw, &remote_initial_commitment_tx, &remote_keys, &Vec::new(), self.our_to_self_delay, &self.secp_ctx)
+               Ok((self.local_keys.sign_remote_commitment(self.channel_value_satoshis, self.feerate_per_kw, &remote_initial_commitment_tx, &remote_keys, &Vec::new(), self.our_to_self_delay, &self.secp_ctx)
                                .map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed"))?.0, remote_initial_commitment_tx))
        }
 
@@ -3276,7 +3236,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
                let our_bitcoin_key = PublicKey::from_secret_key(&self.secp_ctx, self.local_keys.funding_key());
 
                let msg = msgs::UnsignedChannelAnnouncement {
-                       features: msgs::GlobalFeatures::new(),
+                       features: ChannelFeatures::supported(),
                        chain_hash: chain_hash,
                        short_channel_id: self.get_short_channel_id().unwrap(),
                        node_id_1: if were_node_one { our_node_id } else { self.get_their_node_id() },
@@ -3509,7 +3469,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
                                htlcs.push(htlc);
                        }
 
-                       let res = self.local_keys.sign_remote_commitment(self.channel_value_satoshis, &self.get_funding_redeemscript(), feerate_per_kw, &remote_commitment_tx.0, &remote_keys, &htlcs, self.our_to_self_delay, &self.secp_ctx)
+                       let res = self.local_keys.sign_remote_commitment(self.channel_value_satoshis, feerate_per_kw, &remote_commitment_tx.0, &remote_keys, &htlcs, self.our_to_self_delay, &self.secp_ctx)
                                .map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed"))?;
                        signature = res.0;
                        htlc_signatures = res.1;
@@ -4181,6 +4141,7 @@ mod tests {
                        // These aren't set in the test vectors:
                        revocation_base_key: SecretKey::from_slice(&hex::decode("0fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()[..]).unwrap(),
                        commitment_seed: [0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff],
+                       remote_channel_pubkeys: None,
                };
                assert_eq!(PublicKey::from_secret_key(&secp_ctx, chan_keys.funding_key()).serialize()[..],
                                hex::decode("023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb").unwrap()[..]);
@@ -4265,7 +4226,7 @@ mod tests {
                                        assert!(preimage.is_some());
                                }
 
-                               chan.sign_htlc_transaction(&mut htlc_tx, &remote_signature, &preimage, &htlc, &keys).unwrap();
+                               chan_utils::sign_htlc_transaction(&mut htlc_tx, &remote_signature, &preimage, &htlc, &keys.a_htlc_key, &keys.b_htlc_key, &keys.revocation_key, &keys.per_commitment_point, chan.local_keys.htlc_base_key(), &chan.secp_ctx).unwrap();
                                assert_eq!(serialize(&htlc_tx)[..],
                                                hex::decode($tx_hex).unwrap()[..]);
                        };