/// Initial value for revoked commitment downward counter
pub const INITIAL_REVOKED_COMMITMENT_NUMBER: u64 = 1 << 48;
-/// An implementation of ChannelKeys that enforces some policy checks.
+/// An implementation of ChannelKeys that enforces some policy checks. The current checks
+/// are an incomplete set. They include:
+///
+/// - When signing, the holder transaction has not been revoked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 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.
#[derive(Clone)]
pub struct EnforcingChannelKeys {
pub inner: InMemoryChannelKeys,
+ /// The last counterparty commitment number we signed, backwards counting
pub last_commitment_number: Arc<Mutex<Option<u64>>>,
+ /// The last holder commitment number we revoked, backwards counting
pub revoked_commitment: Arc<Mutex<u64>>,
+ pub disable_revocation_policy_check: bool,
}
impl EnforcingChannelKeys {
+ /// Construct an EnforcingChannelKeys
pub fn new(inner: InMemoryChannelKeys) -> Self {
Self {
inner,
last_commitment_number: Arc::new(Mutex::new(None)),
- revoked_commitment: Arc::new(Mutex::new(INITIAL_REVOKED_COMMITMENT_NUMBER))
+ revoked_commitment: Arc::new(Mutex::new(INITIAL_REVOKED_COMMITMENT_NUMBER)),
+ disable_revocation_policy_check: false
}
}
- pub fn new_with_revoked(inner: InMemoryChannelKeys, revoked_commitment: Arc<Mutex<u64>>) -> Self {
+ /// Construct an EnforcingChannelKeys with externally managed storage
+ ///
+ /// Since there are multiple copies of this struct for each channel, some coordination is needed
+ /// so that all copies are aware of revocations. A pointer to this state is provided here, usually
+ /// by an implementation of KeysInterface.
+ pub fn new_with_revoked(inner: InMemoryChannelKeys, revoked_commitment: Arc<Mutex<u64>>, disable_revocation_policy_check: bool) -> Self {
Self {
inner,
last_commitment_number: Arc::new(Mutex::new(None)),
- revoked_commitment
+ revoked_commitment,
+ disable_revocation_policy_check
}
}
}
}
fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
- println!("XXX revoke {} for {}", idx, self.inner.commitment_seed[0]);
-
{
let mut revoked = self.revoked_commitment.lock().unwrap();
assert!(idx == *revoked || idx == *revoked - 1, "can only revoke the current or next unrevoked commitment - trying {}, revoked {}", idx, *revoked);
let revoked = self.revoked_commitment.lock().unwrap();
let commitment_number = trusted_tx.commitment_number();
- println!("XXX sign {} for {}", commitment_number, self.inner.commitment_seed[0]);
if *revoked - 1 != commitment_number && *revoked - 2 != commitment_number {
- println!("can only sign the next two unrevoked commitment numbers, revoked={} vs requested={} for {}",
- *revoked, commitment_number, self.inner.commitment_seed[0]);
- return Err(());
+ if !self.disable_revocation_policy_check {
+ panic!("can only sign the next two unrevoked commitment numbers, revoked={} vs requested={} for {}",
+ *revoked, commitment_number, self.inner.commitment_seed[0])
+ }
}
for (this_htlc, sig) in trusted_tx.htlcs().iter().zip(&commitment_tx.counterparty_htlc_sigs) {
secp_ctx.verify(&sighash, sig, &keys.countersignatory_htlc_key).unwrap();
}
- // TODO: enforce the ChannelKeys contract - error if this commitment was already revoked
- // TODO: need the commitment number
Ok(self.inner.sign_holder_commitment_and_htlcs(commitment_tx, secp_ctx).unwrap())
}
impl Readable for EnforcingChannelKeys {
fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
- let inner: InMemoryChannelKeys = Readable::read(reader)?;
+ let inner = Readable::read(reader)?;
let last_commitment_number = Readable::read(reader)?;
Ok(EnforcingChannelKeys {
inner,
last_commitment_number: Arc::new(Mutex::new(last_commitment_number)),
revoked_commitment: Arc::new(Mutex::new(INITIAL_REVOKED_COMMITMENT_NUMBER)),
+ disable_revocation_policy_check: false,
})
}
}