// You may not use this file except in accordance with one or both of these
// licenses.
-use ln::chan_utils::{HTLCOutputInCommitment, ChannelPublicKeys, HolderCommitmentTransaction, CommitmentTransaction, ChannelTransactionParameters, TrustedCommitmentTransaction};
+use ln::chan_utils::{HTLCOutputInCommitment, ChannelPublicKeys, HolderCommitmentTransaction, CommitmentTransaction, ChannelTransactionParameters, TrustedCommitmentTransaction, ClosingTransaction};
use ln::{chan_utils, msgs};
use chain::keysinterface::{Sign, InMemorySigner, BaseSign};
-use io;
use prelude::*;
use core::cmp;
use sync::{Mutex, Arc};
+#[cfg(test)] use sync::MutexGuard;
use bitcoin::blockdata::transaction::{Transaction, SigHashType};
use bitcoin::util::bip143;
use bitcoin::secp256k1;
use bitcoin::secp256k1::key::{SecretKey, PublicKey};
use bitcoin::secp256k1::{Secp256k1, Signature};
-use util::ser::{Writeable, Writer, Readable};
+use util::ser::{Writeable, Writer};
use io::Error;
-use ln::msgs::DecodeError;
/// Initial value for revoked commitment downward counter
pub const INITIAL_REVOKED_COMMITMENT_NUMBER: u64 = 1 << 48;
/// - When signing, the holder transaction has not been revoked
/// - When revoking, the holder transaction has not been signed
/// - The holder commitment number is monotonic and without gaps
+/// - The revoked holder commitment number is monotonic and without gaps
+/// - There is at least one unrevoked holder transaction at all times
/// - The counterparty commitment number is monotonic and without gaps
/// - The pre-derived keys and pre-built transaction in CommitmentTransaction were correctly built
///
/// Eventually we will probably want to expose a variant of this which would essentially
/// be what you'd want to run on a hardware wallet.
///
+/// Note that counterparty signatures on the holder transaction are not checked, but it should
+/// be in a complete implementation.
+///
/// Note that before we do so we should ensure its serialization format has backwards- and
/// forwards-compatibility prefix/suffixes!
#[derive(Clone)]
disable_revocation_policy_check
}
}
+
+ #[cfg(test)]
+ pub fn get_enforcement_state(&self) -> MutexGuard<EnforcementState> {
+ self.state.lock().unwrap()
+ }
}
impl BaseSign for EnforcingSigner {
fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
{
let mut state = self.state.lock().unwrap();
- assert!(idx == state.revoked_commitment || idx == state.revoked_commitment - 1, "can only revoke the current or next unrevoked commitment - trying {}, revoked {}", idx, state.revoked_commitment);
- state.revoked_commitment = idx;
+ assert!(idx == state.last_holder_revoked_commitment || idx == state.last_holder_revoked_commitment - 1, "can only revoke the current or next unrevoked commitment - trying {}, last revoked {}", idx, state.last_holder_revoked_commitment);
+ assert!(idx > state.last_holder_commitment, "cannot revoke the last holder commitment - attempted to revoke {} last commitment {}", idx, state.last_holder_commitment);
+ state.last_holder_revoked_commitment = idx;
}
self.inner.release_commitment_secret(idx)
}
+ fn validate_holder_commitment(&self, holder_tx: &HolderCommitmentTransaction) -> Result<(), ()> {
+ let mut state = self.state.lock().unwrap();
+ let idx = holder_tx.commitment_number();
+ assert!(idx == state.last_holder_commitment || idx == state.last_holder_commitment - 1, "expecting to validate the current or next holder commitment - trying {}, current {}", idx, state.last_holder_commitment);
+ state.last_holder_commitment = idx;
+ Ok(())
+ }
+
fn pubkeys(&self) -> &ChannelPublicKeys { self.inner.pubkeys() }
fn channel_keys_id(&self) -> [u8; 32] { self.inner.channel_keys_id() }
// These commitment numbers are backwards counting. We expect either the same as the previously encountered,
// or the next one.
assert!(last_commitment_number == actual_commitment_number || last_commitment_number - 1 == actual_commitment_number, "{} doesn't come after {}", actual_commitment_number, last_commitment_number);
+ // Ensure that the counterparty doesn't get more than two broadcastable commitments -
+ // the last and the one we are trying to sign
+ assert!(actual_commitment_number >= state.last_counterparty_revoked_commitment - 2, "cannot sign a commitment if second to last wasn't revoked - signing {} revoked {}", actual_commitment_number, state.last_counterparty_revoked_commitment);
state.last_counterparty_commitment = cmp::min(last_commitment_number, actual_commitment_number)
}
Ok(self.inner.sign_counterparty_commitment(commitment_tx, secp_ctx).unwrap())
}
+ fn validate_counterparty_revocation(&self, idx: u64, _secret: &SecretKey) -> Result<(), ()> {
+ let mut state = self.state.lock().unwrap();
+ assert!(idx == state.last_counterparty_revoked_commitment || idx == state.last_counterparty_revoked_commitment - 1, "expecting to validate the current or next counterparty revocation - trying {}, current {}", idx, state.last_counterparty_revoked_commitment);
+ state.last_counterparty_revoked_commitment = idx;
+ Ok(())
+ }
+
fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
let trusted_tx = self.verify_holder_commitment_tx(commitment_tx, secp_ctx);
let commitment_txid = trusted_tx.txid();
let state = self.state.lock().unwrap();
let commitment_number = trusted_tx.commitment_number();
- if state.revoked_commitment - 1 != commitment_number && state.revoked_commitment - 2 != commitment_number {
+ if state.last_holder_revoked_commitment - 1 != commitment_number && state.last_holder_revoked_commitment - 2 != commitment_number {
if !self.disable_revocation_policy_check {
panic!("can only sign the next two unrevoked commitment numbers, revoked={} vs requested={} for {}",
- state.revoked_commitment, commitment_number, self.inner.commitment_seed[0])
+ state.last_holder_revoked_commitment, commitment_number, self.inner.commitment_seed[0])
}
}
Ok(self.inner.sign_counterparty_htlc_transaction(htlc_tx, input, amount, per_commitment_point, htlc, secp_ctx).unwrap())
}
- fn sign_closing_transaction(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
+ fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
+ closing_tx.verify(self.inner.funding_outpoint().into_bitcoin_outpoint())
+ .expect("derived different closing transaction");
Ok(self.inner.sign_closing_transaction(closing_tx, secp_ctx).unwrap())
}
impl Writeable for EnforcingSigner {
fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
+ // EnforcingSigner has two fields - `inner` ([`InMemorySigner`]) and `state`
+ // ([`EnforcementState`]). `inner` is serialized here and deserialized by
+ // [`KeysInterface::read_chan_signer`]. `state` is managed by [`KeysInterface`]
+ // and will be serialized as needed by the implementation of that trait.
self.inner.write(writer)?;
- // NOTE - the commitment state is maintained by KeysInterface, so we don't persist it
Ok(())
}
}
-impl Readable for EnforcingSigner {
- fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
- let inner = Readable::read(reader)?;
- let state = Arc::new(Mutex::new(EnforcementState::new()));
- Ok(EnforcingSigner {
- inner,
- state,
- disable_revocation_policy_check: false,
- })
- }
-}
-
impl EnforcingSigner {
fn verify_counterparty_commitment_tx<'a, T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &'a CommitmentTransaction, secp_ctx: &Secp256k1<T>) -> TrustedCommitmentTransaction<'a> {
commitment_tx.verify(&self.inner.get_channel_parameters().as_counterparty_broadcastable(),
pub struct EnforcementState {
/// The last counterparty commitment number we signed, backwards counting
pub last_counterparty_commitment: u64,
+ /// The last counterparty commitment they revoked, backwards counting
+ pub last_counterparty_revoked_commitment: u64,
/// The last holder commitment number we revoked, backwards counting
- pub revoked_commitment: u64,
-
+ pub last_holder_revoked_commitment: u64,
+ /// The last validated holder commitment number, backwards counting
+ pub last_holder_commitment: u64,
}
impl EnforcementState {
pub fn new() -> Self {
EnforcementState {
last_counterparty_commitment: INITIAL_REVOKED_COMMITMENT_NUMBER,
- revoked_commitment: INITIAL_REVOKED_COMMITMENT_NUMBER,
+ last_counterparty_revoked_commitment: INITIAL_REVOKED_COMMITMENT_NUMBER,
+ last_holder_revoked_commitment: INITIAL_REVOKED_COMMITMENT_NUMBER,
+ last_holder_commitment: INITIAL_REVOKED_COMMITMENT_NUMBER,
}
}
}