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::blockdata::script::Script;
10 use bitcoin::util::bip143;
12 use bitcoin::secp256k1;
13 use bitcoin::secp256k1::key::{SecretKey, PublicKey};
14 use bitcoin::secp256k1::{Secp256k1, Signature};
15 use util::ser::{Writeable, Writer, Readable};
17 use ln::msgs::DecodeError;
19 /// Enforces some rules on ChannelKeys calls. Eventually we will probably want to expose a variant
20 /// of this which would essentially be what you'd want to run on a hardware wallet.
22 pub struct EnforcingChannelKeys {
23 pub inner: InMemoryChannelKeys,
24 commitment_number_obscure_and_last: Arc<Mutex<(Option<u64>, u64)>>,
27 impl EnforcingChannelKeys {
28 pub fn new(inner: InMemoryChannelKeys) -> Self {
31 commitment_number_obscure_and_last: Arc::new(Mutex::new((None, 0))),
36 impl EnforcingChannelKeys {
37 fn check_keys<T: secp256k1::Signing + secp256k1::Verification>(&self, secp_ctx: &Secp256k1<T>,
38 keys: &TxCreationKeys) {
39 let revocation_base = PublicKey::from_secret_key(secp_ctx, &self.inner.revocation_base_key());
40 let htlc_base = PublicKey::from_secret_key(secp_ctx, &self.inner.htlc_base_key());
42 let remote_points = self.inner.remote_channel_pubkeys.as_ref().unwrap();
44 let keys_expected = TxCreationKeys::new(secp_ctx,
45 &keys.per_commitment_point,
46 &remote_points.delayed_payment_basepoint,
47 &remote_points.htlc_basepoint,
50 if keys != &keys_expected { panic!("derived different per-tx keys") }
54 impl ChannelKeys for EnforcingChannelKeys {
55 fn funding_key(&self) -> &SecretKey { self.inner.funding_key() }
56 fn revocation_base_key(&self) -> &SecretKey { self.inner.revocation_base_key() }
57 fn payment_key(&self) -> &SecretKey { self.inner.payment_key() }
58 fn delayed_payment_base_key(&self) -> &SecretKey { self.inner.delayed_payment_base_key() }
59 fn htlc_base_key(&self) -> &SecretKey { self.inner.htlc_base_key() }
60 fn commitment_seed(&self) -> &[u8; 32] { self.inner.commitment_seed() }
61 fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { self.inner.pubkeys() }
63 fn sign_remote_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, 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, to_self_delay, 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 Ok(self.inner.sign_local_commitment(local_commitment_tx, secp_ctx).unwrap())
86 fn unsafe_sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
87 Ok(self.inner.unsafe_sign_local_commitment(local_commitment_tx, secp_ctx).unwrap())
90 fn sign_local_commitment_htlc_transactions<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, local_csv: u16, secp_ctx: &Secp256k1<T>) -> Result<Vec<Option<Signature>>, ()> {
91 let commitment_txid = local_commitment_tx.txid();
93 for this_htlc in local_commitment_tx.per_htlc.iter() {
94 if this_htlc.0.transaction_output_index.is_some() {
95 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);
97 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&this_htlc.0, &local_commitment_tx.local_keys);
99 let sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, this_htlc.0.amount_msat / 1000)[..]);
100 secp_ctx.verify(&sighash, this_htlc.1.as_ref().unwrap(), &local_commitment_tx.local_keys.b_htlc_key).unwrap();
104 Ok(self.inner.sign_local_commitment_htlc_transactions(local_commitment_tx, local_csv, secp_ctx).unwrap())
107 fn sign_justice_transaction<T: secp256k1::Signing>(&self, justice_tx: &Transaction, input: usize, witness_script: &Script, amount: u64, per_commitment_key: &SecretKey, revocation_pubkey: &PublicKey, is_htlc: bool, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
108 Ok(self.inner.sign_justice_transaction(justice_tx, input, witness_script, amount, per_commitment_key, revocation_pubkey, is_htlc, secp_ctx).unwrap())
111 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
112 Ok(self.inner.sign_closing_transaction(closing_tx, secp_ctx).unwrap())
115 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
116 self.inner.sign_channel_announcement(msg, secp_ctx)
119 fn set_remote_channel_pubkeys(&mut self, channel_pubkeys: &ChannelPublicKeys) {
120 self.inner.set_remote_channel_pubkeys(channel_pubkeys)
124 impl Writeable for EnforcingChannelKeys {
125 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
126 self.inner.write(writer)?;
127 let (obscure, last) = *self.commitment_number_obscure_and_last.lock().unwrap();
128 obscure.write(writer)?;
134 impl Readable for EnforcingChannelKeys {
135 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
136 let inner = Readable::read(reader)?;
137 let obscure_and_last = Readable::read(reader)?;
138 Ok(EnforcingChannelKeys {
140 commitment_number_obscure_and_last: Arc::new(Mutex::new(obscure_and_last))