_ 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, ChannelPublicKeys, HolderCommitmentTransaction, CommitmentTransaction, ChannelTransactionParameters, TrustedCommitmentTransaction};
  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 /// Initial value for revoked commitment downward counter
  28 pub const INITIAL_REVOKED_COMMITMENT_NUMBER: u64 = 1 << 48;
  29
  30 /// An implementation of ChannelKeys that enforces some policy checks.
  31 ///
  32 /// Eventually we will probably want to expose a variant of this which would essentially
  33 /// be what you'd want to run on a hardware wallet.
  34 #[derive(Clone)]
  35 pub struct EnforcingChannelKeys {
  36         pub inner: InMemoryChannelKeys,
  37         pub(crate) last_commitment_number: Arc<Mutex<Option<u64>>>,
  38         pub(crate) revoked_commitment: Arc<Mutex<u64>>,
  39 }
  40
  41 impl EnforcingChannelKeys {
  42         pub fn new(inner: InMemoryChannelKeys) -> Self {
  43                 Self {
  44                         inner,
  45                         last_commitment_number: Arc::new(Mutex::new(None)),
  46                         revoked_commitment: Arc::new(Mutex::new(INITIAL_REVOKED_COMMITMENT_NUMBER))
  47                 }
  48         }
  49
  50         pub fn new_with_revoked(inner: InMemoryChannelKeys, revoked_commitment: Arc<Mutex<u64>>) -> Self {
  51                 Self {
  52                         inner,
  53                         last_commitment_number: Arc::new(Mutex::new(None)),
  54                         revoked_commitment
  55                 }
  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                 println!("XXX revoke {} for {}", idx, self.inner.commitment_seed[0]);
  66
  67                 {
  68                         let mut revoked = self.revoked_commitment.lock().unwrap();
  69                         assert!(idx == *revoked || idx == *revoked - 1, "can only revoke the current or next unrevoked commitment - trying {}, revoked {}", idx, *revoked);
  70                         *revoked = idx;
  71                 }
  72                 self.inner.release_commitment_secret(idx)
  73         }
  74
  75         fn pubkeys(&self) -> &ChannelPublicKeys { self.inner.pubkeys() }
  76         fn key_derivation_params(&self) -> (u64, u64) { self.inner.key_derivation_params() }
  77
  78         fn sign_counterparty_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &CommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()> {
  79                 self.verify_counterparty_commitment_tx(commitment_tx, secp_ctx);
  80
  81                 {
  82                         let mut last_commitment_number_guard = self.last_commitment_number.lock().unwrap();
  83                         let actual_commitment_number = commitment_tx.commitment_number();
  84                         let last_commitment_number = last_commitment_number_guard.unwrap_or(actual_commitment_number);
  85                         // These commitment numbers are backwards counting.  We expect either the same as the previously encountered,
  86                         // or the next one.
  87                         assert!(last_commitment_number == actual_commitment_number || last_commitment_number - 1 == actual_commitment_number, "{} doesn't come after {}", actual_commitment_number, last_commitment_number);
  88                         *last_commitment_number_guard = Some(cmp::min(last_commitment_number, actual_commitment_number))
  89                 }
  90
  91                 Ok(self.inner.sign_counterparty_commitment(commitment_tx, secp_ctx).unwrap())
  92         }
  93
  94         fn sign_holder_commitment_and_htlcs<T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()> {
  95                 let trusted_tx = self.verify_holder_commitment_tx(commitment_tx, secp_ctx);
  96                 let commitment_txid = trusted_tx.txid();
  97                 let holder_csv = self.inner.counterparty_selected_contest_delay();
  98
  99                 let revoked = self.revoked_commitment.lock().unwrap();
 100                 let commitment_number = trusted_tx.commitment_number();
 101                 println!("XXX sign {} for {}", commitment_number, self.inner.commitment_seed[0]);
 102                 if *revoked - 1 != commitment_number && *revoked - 2 != commitment_number {
 103                         println!("can only sign the next two unrevoked commitment numbers, revoked={} vs requested={} for {}",
 104                                  *revoked, commitment_number, self.inner.commitment_seed[0]);
 105                         return Err(());
 106                 }
 107
 108                 for (this_htlc, sig) in trusted_tx.htlcs().iter().zip(&commitment_tx.counterparty_htlc_sigs) {
 109                         assert!(this_htlc.transaction_output_index.is_some());
 110                         let keys = trusted_tx.keys();
 111                         let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, trusted_tx.feerate_per_kw(), holder_csv, &this_htlc, &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
 112
 113                         let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&this_htlc, &keys);
 114
 115                         let sighash = hash_to_message!(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, this_htlc.amount_msat / 1000, SigHashType::All)[..]);
 116                         secp_ctx.verify(&sighash, sig, &keys.countersignatory_htlc_key).unwrap();
 117                 }
 118
 119                 // TODO: enforce the ChannelKeys contract - error if this commitment was already revoked
 120                 // TODO: need the commitment number
 121                 Ok(self.inner.sign_holder_commitment_and_htlcs(commitment_tx, secp_ctx).unwrap())
 122         }
 123
 124         #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
 125         fn unsafe_sign_holder_commitment_and_htlcs<T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()> {
 126                 Ok(self.inner.unsafe_sign_holder_commitment_and_htlcs(commitment_tx, secp_ctx).unwrap())
 127         }
 128
 129         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, ()> {
 130                 Ok(self.inner.sign_justice_transaction(justice_tx, input, amount, per_commitment_key, htlc, secp_ctx).unwrap())
 131         }
 132
 133         fn sign_counterparty_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, ()> {
 134                 Ok(self.inner.sign_counterparty_htlc_transaction(htlc_tx, input, amount, per_commitment_point, htlc, secp_ctx).unwrap())
 135         }
 136
 137         fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
 138                 Ok(self.inner.sign_closing_transaction(closing_tx, secp_ctx).unwrap())
 139         }
 140
 141         fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
 142                 self.inner.sign_channel_announcement(msg, secp_ctx)
 143         }
 144
 145         fn ready_channel(&mut self, channel_parameters: &ChannelTransactionParameters) {
 146                 self.inner.ready_channel(channel_parameters)
 147         }
 148 }
 149
 150
 151 impl Writeable for EnforcingChannelKeys {
 152         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
 153                 self.inner.write(writer)?;
 154                 let last = *self.last_commitment_number.lock().unwrap();
 155                 last.write(writer)?;
 156                 Ok(())
 157         }
 158 }
 159
 160 impl Readable for EnforcingChannelKeys {
 161         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 162                 let inner: InMemoryChannelKeys = Readable::read(reader)?;
 163                 let last_commitment_number = Readable::read(reader)?;
 164                 Ok(EnforcingChannelKeys {
 165                         inner,
 166                         last_commitment_number: Arc::new(Mutex::new(last_commitment_number)),
 167                         revoked_commitment: Arc::new(Mutex::new(INITIAL_REVOKED_COMMITMENT_NUMBER)),
 168                 })
 169         }
 170 }
 171
 172 impl EnforcingChannelKeys {
 173         fn verify_counterparty_commitment_tx<'a, T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &'a CommitmentTransaction, secp_ctx: &Secp256k1<T>) -> TrustedCommitmentTransaction<'a> {
 174                 commitment_tx.verify(&self.inner.get_channel_parameters().as_counterparty_broadcastable(),
 175                                      self.inner.counterparty_pubkeys(), self.inner.pubkeys(), secp_ctx)
 176                         .expect("derived different per-tx keys or built transaction")
 177         }
 178
 179         fn verify_holder_commitment_tx<'a, T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &'a CommitmentTransaction, secp_ctx: &Secp256k1<T>) -> TrustedCommitmentTransaction<'a> {
 180                 commitment_tx.verify(&self.inner.get_channel_parameters().as_holder_broadcastable(),
 181                                      self.inner.pubkeys(), self.inner.counterparty_pubkeys(), secp_ctx)
 182                         .expect("derived different per-tx keys or built transaction")
 183         }
 184 }