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

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   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
   8 // licenses.
   9
  10 use ln::chan_utils::{HTLCOutputInCommitment, TxCreationKeys, ChannelPublicKeys, LocalCommitmentTransaction, PreCalculatedTxCreationKeys};
  11 use ln::{chan_utils, msgs};
  12 use chain::keysinterface::{ChannelKeys, InMemoryChannelKeys};
  13
  14 use std::cmp;
  15 use std::sync::{Mutex, Arc};
  16
  17 use bitcoin::blockdata::transaction::{Transaction, SigHashType};
  18 use bitcoin::util::bip143;
  19
  20 use bitcoin::secp256k1;
  21 use bitcoin::secp256k1::key::{SecretKey, PublicKey};
  22 use bitcoin::secp256k1::{Secp256k1, Signature};
  23 use util::ser::{Writeable, Writer, Readable};
  24 use std::io::Error;
  25 use ln::msgs::DecodeError;
  26
  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.
  29 #[derive(Clone)]
  30 pub struct EnforcingChannelKeys {
  31         pub inner: InMemoryChannelKeys,
  32         commitment_number_obscure_and_last: Arc<Mutex<(Option<u64>, u64)>>,
  33 }
  34
  35 impl EnforcingChannelKeys {
  36         pub fn new(inner: InMemoryChannelKeys) -> Self {
  37                 Self {
  38                         inner,
  39                         commitment_number_obscure_and_last: Arc::new(Mutex::new((None, 0))),
  40                 }
  41         }
  42 }
  43
  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();
  48
  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") }
  56         }
  57 }
  58
  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)
  62         }
  63
  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)
  67         }
  68
  69         fn pubkeys(&self) -> &ChannelPublicKeys { self.inner.pubkeys() }
  70         fn key_derivation_params(&self) -> (u64, u64) { self.inner.key_derivation_params() }
  71
  72         fn sign_remote_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);
  76
  77                 {
  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);
  81                         }
  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)
  85                 }
  86
  87                 Ok(self.inner.sign_remote_commitment(feerate_per_kw, commitment_tx, pre_keys, htlcs, secp_ctx).unwrap())
  88         }
  89
  90         fn sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, 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_local_commitment(local_commitment_tx, secp_ctx).unwrap())
  94         }
  95
  96         #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
  97         fn unsafe_sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
  98                 Ok(self.inner.unsafe_sign_local_commitment(local_commitment_tx, secp_ctx).unwrap())
  99         }
 100
 101         fn sign_local_commitment_htlc_transactions<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Vec<Option<Signature>>, ()> {
 102                 let commitment_txid = local_commitment_tx.txid();
 103                 let local_csv = self.inner.counterparty_selected_contest_delay();
 104
 105                 for this_htlc in local_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, local_commitment_tx.feerate_per_kw, local_csv, &this_htlc.0, &local_commitment_tx.local_keys.broadcaster_delayed_payment_key, &local_commitment_tx.local_keys.revocation_key);
 108
 109                                 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&this_htlc.0, &local_commitment_tx.local_keys);
 110
 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(), &local_commitment_tx.local_keys.countersignatory_htlc_key).unwrap();
 113                         }
 114                 }
 115
 116                 Ok(self.inner.sign_local_commitment_htlc_transactions(local_commitment_tx, secp_ctx).unwrap())
 117         }
 118
 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())
 121         }
 122
 123         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, ()> {
 124                 Ok(self.inner.sign_remote_htlc_transaction(htlc_tx, input, amount, per_commitment_point, htlc, secp_ctx).unwrap())
 125         }
 126
 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())
 129         }
 130
 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)
 133         }
 134
 135         fn on_accept(&mut self, channel_pubkeys: &ChannelPublicKeys, remote_locally_selected_delay: u16, locally_selected_delay: u16) {
 136                 self.inner.on_accept(channel_pubkeys, remote_locally_selected_delay, locally_selected_delay)
 137         }
 138 }
 139
 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)?;
 145                 last.write(writer)?;
 146                 Ok(())
 147         }
 148 }
 149
 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 {
 155                         inner: inner,
 156                         commitment_number_obscure_and_last: Arc::new(Mutex::new(obscure_and_last))
 157                 })
 158         }
 159 }