_ 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 secp256k1;
  12 use secp256k1::key::{SecretKey, PublicKey};
  13 use 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 revocation_base = PublicKey::from_secret_key(secp_ctx, &self.inner.revocation_base_key());
  39                 let payment_base = PublicKey::from_secret_key(secp_ctx, &self.inner.payment_base_key());
  40                 let htlc_base = PublicKey::from_secret_key(secp_ctx, &self.inner.htlc_base_key());
  41
  42                 let remote_points = self.inner.remote_channel_pubkeys.as_ref().unwrap();
  43
  44                 let keys_expected = TxCreationKeys::new(secp_ctx,
  45                                                         &keys.per_commitment_point,
  46                                                         &remote_points.delayed_payment_basepoint,
  47                                                         &remote_points.htlc_basepoint,
  48                                                         &revocation_base,
  49                                                         &payment_base,
  50                                                         &htlc_base).unwrap();
  51                 if keys != &keys_expected { panic!("derived different per-tx keys") }
  52         }
  53 }
  54
  55 impl ChannelKeys for EnforcingChannelKeys {
  56         fn funding_key(&self) -> &SecretKey { self.inner.funding_key() }
  57         fn revocation_base_key(&self) -> &SecretKey { self.inner.revocation_base_key() }
  58         fn payment_base_key(&self) -> &SecretKey { self.inner.payment_base_key() }
  59         fn delayed_payment_base_key(&self) -> &SecretKey { self.inner.delayed_payment_base_key() }
  60         fn htlc_base_key(&self) -> &SecretKey { self.inner.htlc_base_key() }
  61         fn commitment_seed(&self) -> &[u8; 32] { self.inner.commitment_seed() }
  62         fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { self.inner.pubkeys() }
  63
  64         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>), ()> {
  65                 if commitment_tx.input.len() != 1 { panic!("lightning commitment transactions have a single input"); }
  66                 self.check_keys(secp_ctx, keys);
  67                 let obscured_commitment_transaction_number = (commitment_tx.lock_time & 0xffffff) as u64 | ((commitment_tx.input[0].sequence as u64 & 0xffffff) << 3*8);
  68
  69                 {
  70                         let mut commitment_data = self.commitment_number_obscure_and_last.lock().unwrap();
  71                         if commitment_data.0.is_none() {
  72                                 commitment_data.0 = Some(obscured_commitment_transaction_number ^ commitment_data.1);
  73                         }
  74                         let commitment_number = obscured_commitment_transaction_number ^ commitment_data.0.unwrap();
  75                         assert!(commitment_number == commitment_data.1 || commitment_number == commitment_data.1 + 1);
  76                         commitment_data.1 = cmp::max(commitment_number, commitment_data.1)
  77                 }
  78
  79                 Ok(self.inner.sign_remote_commitment(feerate_per_kw, commitment_tx, keys, htlcs, to_self_delay, secp_ctx).unwrap())
  80         }
  81
  82         fn sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
  83                 Ok(self.inner.sign_local_commitment(local_commitment_tx, secp_ctx).unwrap())
  84         }
  85
  86         #[cfg(test)]
  87         fn unsafe_sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
  88                 Ok(self.inner.unsafe_sign_local_commitment(local_commitment_tx, secp_ctx).unwrap())
  89         }
  90
  91         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>>, ()> {
  92                 let commitment_txid = local_commitment_tx.txid();
  93
  94                 for this_htlc in local_commitment_tx.per_htlc.iter() {
  95                         if this_htlc.0.transaction_output_index.is_some() {
  96                                 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
  98                                 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&this_htlc.0, &local_commitment_tx.local_keys);
  99
 100                                 let sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, this_htlc.0.amount_msat / 1000)[..]);
 101                                 secp_ctx.verify(&sighash, this_htlc.1.as_ref().unwrap(), &local_commitment_tx.local_keys.b_htlc_key).unwrap();
 102                         }
 103                 }
 104
 105                 Ok(self.inner.sign_local_commitment_htlc_transactions(local_commitment_tx, local_csv, secp_ctx).unwrap())
 106         }
 107
 108         fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
 109                 Ok(self.inner.sign_closing_transaction(closing_tx, secp_ctx).unwrap())
 110         }
 111
 112         fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
 113                 self.inner.sign_channel_announcement(msg, secp_ctx)
 114         }
 115
 116         fn set_remote_channel_pubkeys(&mut self, channel_pubkeys: &ChannelPublicKeys) {
 117                 self.inner.set_remote_channel_pubkeys(channel_pubkeys)
 118         }
 119 }
 120
 121 impl Writeable for EnforcingChannelKeys {
 122         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
 123                 self.inner.write(writer)?;
 124                 let (obscure, last) = *self.commitment_number_obscure_and_last.lock().unwrap();
 125                 obscure.write(writer)?;
 126                 last.write(writer)?;
 127                 Ok(())
 128         }
 129 }
 130
 131 impl Readable for EnforcingChannelKeys {
 132         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 133                 let inner = Readable::read(reader)?;
 134                 let obscure_and_last = Readable::read(reader)?;
 135                 Ok(EnforcingChannelKeys {
 136                         inner: inner,
 137                         commitment_number_obscure_and_last: Arc::new(Mutex::new(obscure_and_last))
 138                 })
 139         }
 140 }