X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Futil%2Fenforcing_trait_impls.rs;h=baa9e7cd16d98b05be00abcf5d7ebc46a75cbbf8;hb=0dfcacd22c23f69b6526c9c6507d21427a2b7ccb;hp=8229f6048600f79172be41c7451580524831764e;hpb=25c9a37e18b6e3e30a9ad0c8645fb8da34413199;p=rust-lightning diff --git a/lightning/src/util/enforcing_trait_impls.rs b/lightning/src/util/enforcing_trait_impls.rs index 8229f604..baa9e7cd 100644 --- a/lightning/src/util/enforcing_trait_impls.rs +++ b/lightning/src/util/enforcing_trait_impls.rs @@ -9,10 +9,12 @@ use ln::chan_utils::{HTLCOutputInCommitment, ChannelPublicKeys, HolderCommitmentTransaction, CommitmentTransaction, ChannelTransactionParameters, TrustedCommitmentTransaction}; use ln::{chan_utils, msgs}; -use chain::keysinterface::{ChannelKeys, InMemoryChannelKeys}; +use chain::keysinterface::{Sign, InMemorySigner, BaseSign}; -use std::cmp; -use std::sync::{Mutex, Arc}; +use io; +use prelude::*; +use core::cmp; +use sync::{Mutex, Arc}; use bitcoin::blockdata::transaction::{Transaction, SigHashType}; use bitcoin::util::bip143; @@ -21,42 +23,80 @@ use bitcoin::secp256k1; use bitcoin::secp256k1::key::{SecretKey, PublicKey}; use bitcoin::secp256k1::{Secp256k1, Signature}; use util::ser::{Writeable, Writer, Readable}; -use std::io::Error; +use 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 Sign 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 They include: +/// +/// - When signing, the holder transaction has not been revoked +/// - When revoking, the holder transaction has not been signed +/// - The holder commitment number is monotonic and without gaps +/// - The counterparty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. +/// +/// Note that before we do so we should ensure its serialization format has backwards- and +/// forwards-compatibility prefix/suffixes! #[derive(Clone)] -pub struct EnforcingChannelKeys { - pub inner: InMemoryChannelKeys, - last_commitment_number: Arc>>, +pub struct EnforcingSigner { + pub inner: InMemorySigner, + /// The last counterparty commitment number we signed, backwards counting + pub last_commitment_number: Arc>>, + /// The last holder commitment number we revoked, backwards counting + pub revoked_commitment: Arc>, + pub disable_revocation_policy_check: bool, } -impl EnforcingChannelKeys { - pub fn new(inner: InMemoryChannelKeys) -> Self { +impl EnforcingSigner { + /// Construct an EnforcingSigner + pub fn new(inner: InMemorySigner) -> 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 EnforcingSigner 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: InMemorySigner, revoked_commitment: Arc>, disable_revocation_policy_check: bool) -> Self { + Self { + inner, + last_commitment_number: Arc::new(Mutex::new(None)), + revoked_commitment, + disable_revocation_policy_check } } } -impl ChannelKeys for EnforcingChannelKeys { - fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1) -> PublicKey { +impl BaseSign for EnforcingSigner { + fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1) -> PublicKey { self.inner.get_per_commitment_point(idx, secp_ctx) } 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) } fn pubkeys(&self) -> &ChannelPublicKeys { self.inner.pubkeys() } - fn key_derivation_params(&self) -> (u64, u64) { self.inner.key_derivation_params() } + fn channel_keys_id(&self) -> [u8; 32] { self.inner.channel_keys_id() } - fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()> { + fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()> { self.verify_counterparty_commitment_tx(commitment_tx, secp_ctx); { @@ -72,11 +112,20 @@ impl ChannelKeys for EnforcingChannelKeys { Ok(self.inner.sign_counterparty_commitment(commitment_tx, secp_ctx).unwrap()) } - fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()> { + fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()> { let trusted_tx = self.verify_holder_commitment_tx(commitment_tx, secp_ctx); 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(); @@ -88,29 +137,31 @@ 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(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1) -> Result { - Ok(self.inner.unsafe_sign_holder_commitment(commitment_tx, secp_ctx).unwrap()) + fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()> { + Ok(self.inner.unsafe_sign_holder_commitment_and_htlcs(commitment_tx, secp_ctx).unwrap()) + } + + fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1) -> Result { + Ok(self.inner.sign_justice_revoked_output(justice_tx, input, amount, per_commitment_key, secp_ctx).unwrap()) } - fn sign_justice_transaction(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option, secp_ctx: &Secp256k1) -> Result { - Ok(self.inner.sign_justice_transaction(justice_tx, input, amount, per_commitment_key, htlc, secp_ctx).unwrap()) + fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1) -> Result { + Ok(self.inner.sign_justice_revoked_htlc(justice_tx, input, amount, per_commitment_key, htlc, secp_ctx).unwrap()) } - fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1) -> Result { + fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1) -> Result { 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) -> Result { + fn sign_closing_transaction(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1) -> Result { Ok(self.inner.sign_closing_transaction(closing_tx, secp_ctx).unwrap()) } - fn sign_channel_announcement(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1) -> Result { + fn sign_channel_announcement(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1) -> Result { self.inner.sign_channel_announcement(msg, secp_ctx) } @@ -119,8 +170,9 @@ impl ChannelKeys for EnforcingChannelKeys { } } +impl Sign for EnforcingSigner {} -impl Writeable for EnforcingChannelKeys { +impl Writeable for EnforcingSigner { fn write(&self, writer: &mut W) -> Result<(), Error> { self.inner.write(writer)?; let last = *self.last_commitment_number.lock().unwrap(); @@ -129,18 +181,20 @@ impl Writeable for EnforcingChannelKeys { } } -impl Readable for EnforcingChannelKeys { - fn read(reader: &mut R) -> Result { +impl Readable for EnforcingSigner { + fn read(reader: &mut R) -> Result { let inner = Readable::read(reader)?; let last_commitment_number = Readable::read(reader)?; - Ok(EnforcingChannelKeys { + Ok(EnforcingSigner { 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, }) } } -impl EnforcingChannelKeys { +impl EnforcingSigner { fn verify_counterparty_commitment_tx<'a, T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &'a CommitmentTransaction, secp_ctx: &Secp256k1) -> TrustedCommitmentTransaction<'a> { commitment_tx.verify(&self.inner.get_channel_parameters().as_counterparty_broadcastable(), self.inner.counterparty_pubkeys(), self.inner.pubkeys(), secp_ctx)