_ Git - rust-lightning/blob - lightning/src/util/enforcing_trait_impls.rs

   1 use ln::chan_utils::{HTLCOutputInCommitment, TxCreationKeys, ChannelPublicKeys, LocalCommitmentTransaction};
   2 use ln::{chan_utils, msgs};
   3 use chain::keysinterface::{ChannelKeys, InMemoryChannelKeys};
   4
   5 use std::cmp;
   6 use std::sync::{Mutex, Arc};
   7
   8 use bitcoin::blockdata::transaction::Transaction;
   9 use bitcoin::util::bip143;
  10
  11 use bitcoin::secp256k1;
  12 use bitcoin::secp256k1::key::{SecretKey, PublicKey};
  13 use bitcoin::secp256k1::{Secp256k1, Signature};
  14 use util::ser::{Writeable, Writer, Readable};
  15 use std::io::Error;
  16 use ln::msgs::DecodeError;
  17
  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.
  20 #[derive(Clone)]
  21 pub struct EnforcingChannelKeys {
  22         pub inner: InMemoryChannelKeys,
  23         commitment_number_obscure_and_last: Arc<Mutex<(Option<u64>, u64)>>,
  24 }
  25
  26 impl EnforcingChannelKeys {
  27         pub fn new(inner: InMemoryChannelKeys) -> Self {
  28                 Self {
  29                         inner,
  30                         commitment_number_obscure_and_last: Arc::new(Mutex::new((None, 0))),
  31                 }
  32         }
  33 }
  34
  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_channel_pubkeys.as_ref().unwrap();
  39
  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") }
  47         }
  48 }
  49
  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)
  53         }
  54
  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)
  58         }
  59
  60         fn pubkeys(&self) -> &ChannelPublicKeys { self.inner.pubkeys() }
  61         fn key_derivation_params(&self) -> (u64, u64) { self.inner.key_derivation_params() }
  62
  63         fn sign_remote_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, feerate_per_kw: u32, 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);
  67
  68                 {
  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);
  72                         }
  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)
  76                 }
  77
  78                 Ok(self.inner.sign_remote_commitment(feerate_per_kw, commitment_tx, keys, htlcs, to_self_delay, secp_ctx).unwrap())
  79         }
  80
  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())
  85         }
  86
  87         #[cfg(test)]
  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())
  90         }
  91
  92         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>>, ()> {
  93                 let commitment_txid = local_commitment_tx.txid();
  94
  95                 for this_htlc in local_commitment_tx.per_htlc.iter() {
  96                         if this_htlc.0.transaction_output_index.is_some() {
  97                                 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);
  98
  99                                 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&this_htlc.0, &local_commitment_tx.local_keys);
 100
 101                                 let sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, this_htlc.0.amount_msat / 1000)[..]);
 102                                 secp_ctx.verify(&sighash, this_htlc.1.as_ref().unwrap(), &local_commitment_tx.local_keys.b_htlc_key).unwrap();
 103                         }
 104                 }
 105
 106                 Ok(self.inner.sign_local_commitment_htlc_transactions(local_commitment_tx, local_csv, secp_ctx).unwrap())
 107         }
 108
 109         fn sign_justice_transaction<T: secp256k1::Signing + secp256k1::Verification>(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option<HTLCOutputInCommitment>, on_remote_tx_csv: u16, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
 110                 Ok(self.inner.sign_justice_transaction(justice_tx, input, amount, per_commitment_key, htlc, on_remote_tx_csv, secp_ctx).unwrap())
 111         }
 112
 113         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, ()> {
 114                 Ok(self.inner.sign_remote_htlc_transaction(htlc_tx, input, amount, per_commitment_point, htlc, secp_ctx).unwrap())
 115         }
 116
 117         fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
 118                 Ok(self.inner.sign_closing_transaction(closing_tx, secp_ctx).unwrap())
 119         }
 120
 121         fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
 122                 self.inner.sign_channel_announcement(msg, secp_ctx)
 123         }
 124
 125         fn set_remote_channel_pubkeys(&mut self, channel_pubkeys: &ChannelPublicKeys) {
 126                 self.inner.set_remote_channel_pubkeys(channel_pubkeys)
 127         }
 128 }
 129
 130 impl Writeable for EnforcingChannelKeys {
 131         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
 132                 self.inner.write(writer)?;
 133                 let (obscure, last) = *self.commitment_number_obscure_and_last.lock().unwrap();
 134                 obscure.write(writer)?;
 135                 last.write(writer)?;
 136                 Ok(())
 137         }
 138 }
 139
 140 impl Readable for EnforcingChannelKeys {
 141         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 142                 let inner = Readable::read(reader)?;
 143                 let obscure_and_last = Readable::read(reader)?;
 144                 Ok(EnforcingChannelKeys {
 145                         inner: inner,
 146                         commitment_number_obscure_and_last: Arc::new(Mutex::new(obscure_and_last))
 147                 })
 148         }
 149 }