1 // This file is Copyright its original authors, visible in version control
4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7 // You may not use this file except in accordance with one or both of these
10 use ln::chan_utils::{HTLCOutputInCommitment, TxCreationKeys, ChannelPublicKeys, HolderCommitmentTransaction, PreCalculatedTxCreationKeys};
11 use ln::{chan_utils, msgs};
12 use chain::keysinterface::{ChannelKeys, InMemoryChannelKeys};
15 use std::sync::{Mutex, Arc};
17 use bitcoin::blockdata::transaction::{Transaction, SigHashType};
18 use bitcoin::util::bip143;
20 use bitcoin::secp256k1;
21 use bitcoin::secp256k1::key::{SecretKey, PublicKey};
22 use bitcoin::secp256k1::{Secp256k1, Signature};
23 use util::ser::{Writeable, Writer, Readable};
25 use ln::msgs::DecodeError;
27 /// Enforces some rules on ChannelKeys calls. Eventually we will probably want to expose a variant
28 /// of this which would essentially be what you'd want to run on a hardware wallet.
30 pub struct EnforcingChannelKeys {
31 pub inner: InMemoryChannelKeys,
32 commitment_number_obscure_and_last: Arc<Mutex<(Option<u64>, u64)>>,
35 impl EnforcingChannelKeys {
36 pub fn new(inner: InMemoryChannelKeys) -> Self {
39 commitment_number_obscure_and_last: Arc::new(Mutex::new((None, 0))),
44 impl EnforcingChannelKeys {
45 fn check_keys<T: secp256k1::Signing + secp256k1::Verification>(&self, secp_ctx: &Secp256k1<T>,
46 keys: &TxCreationKeys) {
47 let remote_points = self.inner.counterparty_pubkeys();
49 let keys_expected = TxCreationKeys::derive_new(secp_ctx,
50 &keys.per_commitment_point,
51 &remote_points.delayed_payment_basepoint,
52 &remote_points.htlc_basepoint,
53 &self.inner.pubkeys().revocation_basepoint,
54 &self.inner.pubkeys().htlc_basepoint).unwrap();
55 if keys != &keys_expected { panic!("derived different per-tx keys") }
59 impl ChannelKeys for EnforcingChannelKeys {
60 fn get_per_commitment_point<T: secp256k1::Signing + secp256k1::Verification>(&self, idx: u64, secp_ctx: &Secp256k1<T>) -> PublicKey {
61 self.inner.get_per_commitment_point(idx, secp_ctx)
64 fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
65 // TODO: enforce the ChannelKeys contract - error here if we already signed this commitment
66 self.inner.release_commitment_secret(idx)
69 fn pubkeys(&self) -> &ChannelPublicKeys { self.inner.pubkeys() }
70 fn key_derivation_params(&self) -> (u64, u64) { self.inner.key_derivation_params() }
72 fn sign_counterparty_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, feerate_per_kw: u32, commitment_tx: &Transaction, pre_keys: &PreCalculatedTxCreationKeys, htlcs: &[&HTLCOutputInCommitment], secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()> {
73 if commitment_tx.input.len() != 1 { panic!("lightning commitment transactions have a single input"); }
74 self.check_keys(secp_ctx, pre_keys.trust_key_derivation());
75 let obscured_commitment_transaction_number = (commitment_tx.lock_time & 0xffffff) as u64 | ((commitment_tx.input[0].sequence as u64 & 0xffffff) << 3*8);
78 let mut commitment_data = self.commitment_number_obscure_and_last.lock().unwrap();
79 if commitment_data.0.is_none() {
80 commitment_data.0 = Some(obscured_commitment_transaction_number ^ commitment_data.1);
82 let commitment_number = obscured_commitment_transaction_number ^ commitment_data.0.unwrap();
83 assert!(commitment_number == commitment_data.1 || commitment_number == commitment_data.1 + 1);
84 commitment_data.1 = cmp::max(commitment_number, commitment_data.1)
87 Ok(self.inner.sign_counterparty_commitment(feerate_per_kw, commitment_tx, pre_keys, htlcs, secp_ctx).unwrap())
90 fn sign_holder_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, holder_commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
91 // TODO: enforce the ChannelKeys contract - error if this commitment was already revoked
92 // TODO: need the commitment number
93 Ok(self.inner.sign_holder_commitment(holder_commitment_tx, secp_ctx).unwrap())
96 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
97 fn unsafe_sign_holder_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, holder_commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
98 Ok(self.inner.unsafe_sign_holder_commitment(holder_commitment_tx, secp_ctx).unwrap())
101 fn sign_holder_commitment_htlc_transactions<T: secp256k1::Signing + secp256k1::Verification>(&self, holder_commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Vec<Option<Signature>>, ()> {
102 let commitment_txid = holder_commitment_tx.txid();
103 let holder_csv = self.inner.counterparty_selected_contest_delay();
105 for this_htlc in holder_commitment_tx.per_htlc.iter() {
106 if this_htlc.0.transaction_output_index.is_some() {
107 let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, holder_commitment_tx.feerate_per_kw, holder_csv, &this_htlc.0, &holder_commitment_tx.keys.broadcaster_delayed_payment_key, &holder_commitment_tx.keys.revocation_key);
109 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&this_htlc.0, &holder_commitment_tx.keys);
111 let sighash = hash_to_message!(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, this_htlc.0.amount_msat / 1000, SigHashType::All)[..]);
112 secp_ctx.verify(&sighash, this_htlc.1.as_ref().unwrap(), &holder_commitment_tx.keys.countersignatory_htlc_key).unwrap();
116 Ok(self.inner.sign_holder_commitment_htlc_transactions(holder_commitment_tx, secp_ctx).unwrap())
119 fn sign_justice_transaction<T: secp256k1::Signing + secp256k1::Verification>(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option<HTLCOutputInCommitment>, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
120 Ok(self.inner.sign_justice_transaction(justice_tx, input, amount, per_commitment_key, htlc, secp_ctx).unwrap())
123 fn sign_counterparty_htlc_transaction<T: secp256k1::Signing + secp256k1::Verification>(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
124 Ok(self.inner.sign_counterparty_htlc_transaction(htlc_tx, input, amount, per_commitment_point, htlc, secp_ctx).unwrap())
127 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
128 Ok(self.inner.sign_closing_transaction(closing_tx, secp_ctx).unwrap())
131 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
132 self.inner.sign_channel_announcement(msg, secp_ctx)
135 fn on_accept(&mut self, channel_pubkeys: &ChannelPublicKeys, counterparty_selected_delay: u16, holder_selected_delay: u16) {
136 self.inner.on_accept(channel_pubkeys, counterparty_selected_delay, holder_selected_delay)
140 impl Writeable for EnforcingChannelKeys {
141 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
142 self.inner.write(writer)?;
143 let (obscure, last) = *self.commitment_number_obscure_and_last.lock().unwrap();
144 obscure.write(writer)?;
150 impl Readable for EnforcingChannelKeys {
151 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
152 let inner = Readable::read(reader)?;
153 let obscure_and_last = Readable::read(reader)?;
154 Ok(EnforcingChannelKeys {
156 commitment_number_obscure_and_last: Arc::new(Mutex::new(obscure_and_last))