Add additional Clone derives

[rust-lightning] / lightning / src / util / enforcing_trait_impls.rs

diff --git a/lightning/src/util/enforcing_trait_impls.rs b/lightning/src/util/enforcing_trait_impls.rs
index 8229f6048600f79172be41c7451580524831764e..88c1754f13599162b185350612b2b2f03abcd87a 100644 (file)
--- a/lightning/src/util/enforcing_trait_impls.rs
+++ b/lightning/src/util/enforcing_trait_impls.rs
@@ -24,21 +24,52 @@ use util::ser::{Writeable, Writer, Readable};
 use std::io::Error;
 use ln::msgs::DecodeError;
 
-/// An implementation of ChannelKeys that enforces some policy checks.
+/// 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.  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+/// - When signing, the holder transaction has not been revoked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,
-       last_commitment_number: Arc<Mutex<Option<u64>>>,
+       /// 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)),
+                       disable_revocation_policy_check: false
+               }
+       }
+
+       /// 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,
+                       disable_revocation_policy_check
                }
        }
 }
@@ -49,7 +80,11 @@ impl ChannelKeys for EnforcingChannelKeys {
        }
 
        fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
-               // TODO: enforce the ChannelKeys contract - error here if we already signed this commitment
+               {
+                       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);
+                       *revoked = idx;
+               }
                self.inner.release_commitment_secret(idx)
        }
 
@@ -77,6 +112,15 @@ impl ChannelKeys for EnforcingChannelKeys {
                let commitment_txid = trusted_tx.txid();
                let holder_csv = self.inner.counterparty_selected_contest_delay();
 
+               let revoked = self.revoked_commitment.lock().unwrap();
+               let commitment_number = trusted_tx.commitment_number();
+               if *revoked - 1 != commitment_number && *revoked - 2 != commitment_number {
+                       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) {
                        assert!(this_htlc.transaction_output_index.is_some());
                        let keys = trusted_tx.keys();
@@ -88,14 +132,12 @@ impl ChannelKeys for EnforcingChannelKeys {
                        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())
        }
 
        #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
-       fn unsafe_sign_holder_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
-               Ok(self.inner.unsafe_sign_holder_commitment(commitment_tx, secp_ctx).unwrap())
+       fn unsafe_sign_holder_commitment_and_htlcs<T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()> {
+               Ok(self.inner.unsafe_sign_holder_commitment_and_htlcs(commitment_tx, secp_ctx).unwrap())
        }
 
        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, ()> {
@@ -135,7 +177,9 @@ impl Readable for EnforcingChannelKeys {
                let last_commitment_number = Readable::read(reader)?;
                Ok(EnforcingChannelKeys {
                        inner,
-                       last_commitment_number: Arc::new(Mutex::new(last_commitment_number))
+                       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,
                })
        }
 }