1 use ln::chan_utils::{HTLCOutputInCommitment, TxCreationKeys, ChannelPublicKeys, LocalCommitmentTransaction};
2 use ln::{chan_utils, msgs};
3 use chain::keysinterface::{ChannelKeys, InMemoryChannelKeys};
6 use std::sync::{Mutex, Arc};
8 use bitcoin::blockdata::transaction::Transaction;
9 use bitcoin::util::bip143;
11 use bitcoin::secp256k1;
12 use bitcoin::secp256k1::key::{SecretKey, PublicKey};
13 use bitcoin::secp256k1::{Secp256k1, Signature};
14 use util::ser::{Writeable, Writer, Readable};
16 use ln::msgs::DecodeError;
18 /// Enforces some rules on ChannelKeys calls. Eventually we will probably want to expose a variant
19 /// of this which would essentially be what you'd want to run on a hardware wallet.
21 pub struct EnforcingChannelKeys {
22 pub inner: InMemoryChannelKeys,
23 commitment_number_obscure_and_last: Arc<Mutex<(Option<u64>, u64)>>,
26 impl EnforcingChannelKeys {
27 pub fn new(inner: InMemoryChannelKeys) -> Self {
30 commitment_number_obscure_and_last: Arc::new(Mutex::new((None, 0))),
35 impl EnforcingChannelKeys {
36 fn check_keys<T: secp256k1::Signing + secp256k1::Verification>(&self, secp_ctx: &Secp256k1<T>,
37 keys: &TxCreationKeys) {
38 let remote_points = self.inner.remote_pubkeys();
40 let keys_expected = TxCreationKeys::new(secp_ctx,
41 &keys.per_commitment_point,
42 &remote_points.delayed_payment_basepoint,
43 &remote_points.htlc_basepoint,
44 &self.inner.pubkeys().revocation_basepoint,
45 &self.inner.pubkeys().htlc_basepoint).unwrap();
46 if keys != &keys_expected { panic!("derived different per-tx keys") }
50 impl ChannelKeys for EnforcingChannelKeys {
51 fn get_per_commitment_point<T: secp256k1::Signing + secp256k1::Verification>(&self, idx: u64, secp_ctx: &Secp256k1<T>) -> PublicKey {
52 self.inner.get_per_commitment_point(idx, secp_ctx)
55 fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
56 // TODO: enforce the ChannelKeys contract - error here if we already signed this commitment
57 self.inner.release_commitment_secret(idx)
60 fn pubkeys(&self) -> &ChannelPublicKeys { self.inner.pubkeys() }
61 fn key_derivation_params(&self) -> (u64, u64) { self.inner.key_derivation_params() }
63 fn sign_remote_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, feerate_per_kw: u32, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()> {
64 if commitment_tx.input.len() != 1 { panic!("lightning commitment transactions have a single input"); }
65 self.check_keys(secp_ctx, keys);
66 let obscured_commitment_transaction_number = (commitment_tx.lock_time & 0xffffff) as u64 | ((commitment_tx.input[0].sequence as u64 & 0xffffff) << 3*8);
69 let mut commitment_data = self.commitment_number_obscure_and_last.lock().unwrap();
70 if commitment_data.0.is_none() {
71 commitment_data.0 = Some(obscured_commitment_transaction_number ^ commitment_data.1);
73 let commitment_number = obscured_commitment_transaction_number ^ commitment_data.0.unwrap();
74 assert!(commitment_number == commitment_data.1 || commitment_number == commitment_data.1 + 1);
75 commitment_data.1 = cmp::max(commitment_number, commitment_data.1)
78 Ok(self.inner.sign_remote_commitment(feerate_per_kw, commitment_tx, keys, htlcs, secp_ctx).unwrap())
81 fn sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
82 // TODO: enforce the ChannelKeys contract - error if this commitment was already revoked
83 // TODO: need the commitment number
84 Ok(self.inner.sign_local_commitment(local_commitment_tx, secp_ctx).unwrap())
88 fn unsafe_sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
89 Ok(self.inner.unsafe_sign_local_commitment(local_commitment_tx, secp_ctx).unwrap())
92 fn sign_local_commitment_htlc_transactions<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Vec<Option<Signature>>, ()> {
93 let commitment_txid = local_commitment_tx.txid();
94 let local_csv = self.inner.remote_to_self_delay();
96 for this_htlc in local_commitment_tx.per_htlc.iter() {
97 if this_htlc.0.transaction_output_index.is_some() {
98 let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, local_commitment_tx.feerate_per_kw, local_csv, &this_htlc.0, &local_commitment_tx.local_keys.a_delayed_payment_key, &local_commitment_tx.local_keys.revocation_key);
100 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&this_htlc.0, &local_commitment_tx.local_keys);
102 let sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, this_htlc.0.amount_msat / 1000)[..]);
103 secp_ctx.verify(&sighash, this_htlc.1.as_ref().unwrap(), &local_commitment_tx.local_keys.b_htlc_key).unwrap();
107 Ok(self.inner.sign_local_commitment_htlc_transactions(local_commitment_tx, secp_ctx).unwrap())
110 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, ()> {
111 Ok(self.inner.sign_justice_transaction(justice_tx, input, amount, per_commitment_key, htlc, secp_ctx).unwrap())
114 fn sign_remote_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, ()> {
115 Ok(self.inner.sign_remote_htlc_transaction(htlc_tx, input, amount, per_commitment_point, htlc, secp_ctx).unwrap())
118 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
119 Ok(self.inner.sign_closing_transaction(closing_tx, secp_ctx).unwrap())
122 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
123 self.inner.sign_channel_announcement(msg, secp_ctx)
126 fn on_accept(&mut self, channel_pubkeys: &ChannelPublicKeys, remote_to_self_delay: u16, local_to_self_delay: u16) {
127 self.inner.on_accept(channel_pubkeys, remote_to_self_delay, local_to_self_delay)
131 impl Writeable for EnforcingChannelKeys {
132 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
133 self.inner.write(writer)?;
134 let (obscure, last) = *self.commitment_number_obscure_and_last.lock().unwrap();
135 obscure.write(writer)?;
141 impl Readable for EnforcingChannelKeys {
142 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
143 let inner = Readable::read(reader)?;
144 let obscure_and_last = Readable::read(reader)?;
145 Ok(EnforcingChannelKeys {
147 commitment_number_obscure_and_last: Arc::new(Mutex::new(obscure_and_last))