X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fchain%2Fkeysinterface.rs;h=4a3a937a5c4586824ce0b875525b737ca39bdd67;hb=45d4d26987666c45832814649233462d9d194c62;hp=1cc41b0f8fa6882f498997eb2840f6ac605f9bdc;hpb=21d0a955efd016d83ed14dd644f6cbe696e56ad7;p=rust-lightning diff --git a/lightning/src/chain/keysinterface.rs b/lightning/src/chain/keysinterface.rs index 1cc41b0f..4a3a937a 100644 --- a/lightning/src/chain/keysinterface.rs +++ b/lightning/src/chain/keysinterface.rs @@ -33,7 +33,7 @@ use util::ser::{Writeable, Writer, Readable}; use chain::transaction::OutPoint; use ln::chan_utils; -use ln::chan_utils::{HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, HolderCommitmentTransaction, PreCalculatedTxCreationKeys}; +use ln::chan_utils::{HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, HolderCommitmentTransaction, ChannelTransactionParameters, CommitmentTransaction}; use ln::msgs::UnsignedChannelAnnouncement; use std::sync::atomic::{AtomicUsize, Ordering}; @@ -45,7 +45,7 @@ use ln::msgs::DecodeError; /// spend on-chain. The information needed to do this is provided in this enum, including the /// outpoint describing which txid and output index is available, the full output which exists at /// that txid/index, and any keys or other information required to sign. -#[derive(Clone, PartialEq)] +#[derive(Clone, Debug, PartialEq)] pub enum SpendableOutputDescriptor { /// An output to a script which was provided via KeysInterface, thus you should already know /// how to spend it. No keys are provided as rust-lightning was never given any keys - only the @@ -79,7 +79,7 @@ pub enum SpendableOutputDescriptor { /// /// To derive the revocation_pubkey provided here (which is used in the witness /// script generation), you must pass the counterparty revocation_basepoint (which appears in the - /// call to ChannelKeys::on_accept) and the provided per_commitment point + /// call to ChannelKeys::ready_channel) and the provided per_commitment point /// to chan_utils::derive_public_revocation_key. /// /// The witness script which is hashed and included in the output script_pubkey may be @@ -204,7 +204,7 @@ impl Readable for SpendableOutputDescriptor { // routine). // TODO: We should remove Clone by instead requesting a new ChannelKeys copy when we create // ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors. -pub trait ChannelKeys : Send+Clone { +pub trait ChannelKeys : Send+Clone + Writeable { /// Gets the per-commitment point for a specific commitment number /// /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards. @@ -231,40 +231,34 @@ pub trait ChannelKeys : Send+Clone { /// Note that if signing fails or is rejected, the channel will be force-closed. // // TODO: Document the things someone using this interface should enforce before signing. - // TODO: Add more input vars to enable better checking (preferably removing commitment_tx and - // making the callee generate it via some util function we expose)! - fn sign_counterparty_commitment(&self, feerate_per_kw: u32, commitment_tx: &Transaction, keys: &PreCalculatedTxCreationKeys, htlcs: &[&HTLCOutputInCommitment], secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()>; + fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()>; /// Create a signature for a holder's commitment transaction. This will only ever be called with - /// the same holder_commitment_tx (or a copy thereof), though there are currently no guarantees + /// the same commitment_tx (or a copy thereof), though there are currently no guarantees /// that it will not be called multiple times. /// An external signer implementation should check that the commitment has not been revoked. // // TODO: Document the things someone using this interface should enforce before signing. - // TODO: Add more input vars to enable better checking (preferably removing commitment_tx and - fn sign_holder_commitment(&self, holder_commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1) -> Result; + fn sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1) -> Result; /// Same as sign_holder_commitment, but exists only for tests to get access to holder commitment /// transactions which will be broadcasted later, after the channel has moved on to a newer /// state. Thus, needs its own method as sign_holder_commitment may enforce that we only ever /// get called once. #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))] - fn unsafe_sign_holder_commitment(&self, holder_commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1) -> Result; + fn unsafe_sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1) -> Result; /// Create a signature for each HTLC transaction spending a holder's commitment transaction. /// /// Unlike sign_holder_commitment, this may be called multiple times with *different* - /// holder_commitment_tx values. While this will never be called with a revoked - /// holder_commitment_tx, it is possible that it is called with the second-latest - /// holder_commitment_tx (only if we haven't yet revoked it) if some watchtower/secondary + /// commitment_tx values. While this will never be called with a revoked + /// commitment_tx, it is possible that it is called with the second-latest + /// commitment_tx (only if we haven't yet revoked it) if some watchtower/secondary /// ChannelMonitor decided to broadcast before it had been updated to the latest. /// /// Either an Err should be returned, or a Vec with one entry for each HTLC which exists in - /// holder_commitment_tx. For those HTLCs which have transaction_output_index set to None - /// (implying they were considered dust at the time the commitment transaction was negotiated), - /// a corresponding None should be included in the return value. All other positions in the - /// return value must contain a signature. - fn sign_holder_commitment_htlc_transactions(&self, holder_commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1) -> Result>, ()>; + /// commitment_tx. + fn sign_holder_commitment_htlc_transactions(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1) -> Result, ()>; /// Create a signature for the given input in a transaction spending an HTLC or commitment /// transaction output when our counterparty broadcasts an old state. @@ -319,13 +313,17 @@ pub trait ChannelKeys : Send+Clone { /// protocol. fn sign_channel_announcement(&self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1) -> Result; - /// Set the counterparty channel basepoints and counterparty_selected/holder_selected_contest_delay. - /// This is done immediately on incoming channels and as soon as the channel is accepted on outgoing channels. + /// Set the counterparty static channel data, including basepoints, + /// counterparty_selected/holder_selected_contest_delay and funding outpoint. + /// This is done as soon as the funding outpoint is known. Since these are static channel data, + /// they MUST NOT be allowed to change to different values once set. + /// + /// channel_parameters.is_populated() MUST be true. /// /// We bind holder_selected_contest_delay late here for API convenience. /// /// Will be called before any signatures are applied. - fn on_accept(&mut self, channel_points: &ChannelPublicKeys, counterparty_selected_contest_delay: u16, holder_selected_contest_delay: u16); + fn ready_channel(&mut self, channel_parameters: &ChannelTransactionParameters); } /// A trait to describe an object which can get user secrets and key material. @@ -346,29 +344,21 @@ pub trait KeysInterface: Send + Sync { /// onion packets and for temporary channel IDs. There is no requirement that these be /// persisted anywhere, though they must be unique across restarts. fn get_secure_random_bytes(&self) -> [u8; 32]; -} -#[derive(Clone)] -/// Holds late-bound channel data. -/// This data is available after the channel is known to be accepted, either -/// when receiving an open_channel for an inbound channel or when -/// receiving accept_channel for an outbound channel. -struct AcceptedChannelData { - /// Counterparty public keys and base points - counterparty_channel_pubkeys: ChannelPublicKeys, - /// The contest_delay value specified by our counterparty and applied on holder-broadcastable - /// transactions, ie the amount of time that we have to wait to recover our funds if we - /// broadcast a transaction. You'll likely want to pass this to the - /// ln::chan_utils::build*_transaction functions when signing holder's transactions. - counterparty_selected_contest_delay: u16, - /// The contest_delay value specified by us and applied on transactions broadcastable - /// by our counterparty, ie the amount of time that they have to wait to recover their funds - /// if they broadcast a transaction. - holder_selected_contest_delay: u16, + /// Reads a `ChanKeySigner` for this `KeysInterface` from the given input stream. + /// This is only called during deserialization of other objects which contain + /// `ChannelKeys`-implementing objects (ie `ChannelMonitor`s and `ChannelManager`s). + /// The bytes are exactly those which `::write()` writes, and + /// contain no versioning scheme. You may wish to include your own version prefix and ensure + /// you've read all of the provided bytes to ensure no corruption occurred. + fn read_chan_signer(&self, reader: &[u8]) -> Result; } #[derive(Clone)] /// A simple implementation of ChannelKeys that just keeps the private keys in memory. +/// +/// This implementation performs no policy checks and is insufficient by itself as +/// a secure external signer. pub struct InMemoryChannelKeys { /// Private key of anchor tx pub funding_key: SecretKey, @@ -385,7 +375,7 @@ pub struct InMemoryChannelKeys { /// Holder public keys and basepoints pub(crate) holder_channel_pubkeys: ChannelPublicKeys, /// Counterparty public keys and counterparty/holder selected_contest_delay, populated on channel acceptance - accepted_channel_data: Option, + channel_parameters: Option, /// The total value of this channel channel_value_satoshis: u64, /// Key derivation parameters @@ -417,7 +407,7 @@ impl InMemoryChannelKeys { commitment_seed, channel_value_satoshis, holder_channel_pubkeys, - accepted_channel_data: None, + channel_parameters: None, key_derivation_params, } } @@ -439,21 +429,36 @@ impl InMemoryChannelKeys { } /// Counterparty pubkeys. - /// Will panic if on_accept wasn't called. - pub fn counterparty_pubkeys(&self) -> &ChannelPublicKeys { &self.accepted_channel_data.as_ref().unwrap().counterparty_channel_pubkeys } + /// Will panic if ready_channel wasn't called. + pub fn counterparty_pubkeys(&self) -> &ChannelPublicKeys { &self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().pubkeys } /// The contest_delay value specified by our counterparty and applied on holder-broadcastable /// transactions, ie the amount of time that we have to wait to recover our funds if we - /// broadcast a transaction. You'll likely want to pass this to the - /// ln::chan_utils::build*_transaction functions when signing holder's transactions. - /// Will panic if on_accept wasn't called. - pub fn counterparty_selected_contest_delay(&self) -> u16 { self.accepted_channel_data.as_ref().unwrap().counterparty_selected_contest_delay } + /// broadcast a transaction. + /// Will panic if ready_channel wasn't called. + pub fn counterparty_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().selected_contest_delay } /// The contest_delay value specified by us and applied on transactions broadcastable /// by our counterparty, ie the amount of time that they have to wait to recover their funds /// if they broadcast a transaction. - /// Will panic if on_accept wasn't called. - pub fn holder_selected_contest_delay(&self) -> u16 { self.accepted_channel_data.as_ref().unwrap().holder_selected_contest_delay } + /// Will panic if ready_channel wasn't called. + pub fn holder_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().holder_selected_contest_delay } + + /// Whether the holder is the initiator + /// Will panic if ready_channel wasn't called. + pub fn is_outbound(&self) -> bool { self.get_channel_parameters().is_outbound_from_holder } + + /// Funding outpoint + /// Will panic if ready_channel wasn't called. + pub fn funding_outpoint(&self) -> &OutPoint { self.get_channel_parameters().funding_outpoint.as_ref().unwrap() } + + /// Obtain a ChannelTransactionParameters for this channel, to be used when verifying or + /// building transactions. + /// + /// Will panic if ready_channel wasn't called. + pub fn get_channel_parameters(&self) -> &ChannelTransactionParameters { + self.channel_parameters.as_ref().unwrap() + } } impl ChannelKeys for InMemoryChannelKeys { @@ -469,56 +474,50 @@ impl ChannelKeys for InMemoryChannelKeys { fn pubkeys(&self) -> &ChannelPublicKeys { &self.holder_channel_pubkeys } fn key_derivation_params(&self) -> (u64, u64) { self.key_derivation_params } - fn sign_counterparty_commitment(&self, feerate_per_kw: u32, commitment_tx: &Transaction, pre_keys: &PreCalculatedTxCreationKeys, htlcs: &[&HTLCOutputInCommitment], secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()> { - if commitment_tx.input.len() != 1 { return Err(()); } - let keys = pre_keys.trust_key_derivation(); + fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()> { + let trusted_tx = commitment_tx.trust(); + let keys = trusted_tx.keys(); let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key); - let accepted_data = self.accepted_channel_data.as_ref().expect("must accept before signing"); - let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &accepted_data.counterparty_channel_pubkeys.funding_pubkey); - - let commitment_sighash = hash_to_message!(&bip143::SigHashCache::new(commitment_tx).signature_hash(0, &channel_funding_redeemscript, self.channel_value_satoshis, SigHashType::All)[..]); - let commitment_sig = secp_ctx.sign(&commitment_sighash, &self.funding_key); - - let commitment_txid = commitment_tx.txid(); - - let mut htlc_sigs = Vec::with_capacity(htlcs.len()); - for ref htlc in htlcs { - if let Some(_) = htlc.transaction_output_index { - let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, feerate_per_kw, accepted_data.holder_selected_contest_delay, htlc, &keys.broadcaster_delayed_payment_key, &keys.revocation_key); - let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys); - let htlc_sighash = hash_to_message!(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, SigHashType::All)[..]); - let our_htlc_key = match chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key) { - Ok(s) => s, - Err(_) => return Err(()), - }; - htlc_sigs.push(secp_ctx.sign(&htlc_sighash, &our_htlc_key)); - } + let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey); + + let built_tx = trusted_tx.built_transaction(); + let commitment_sig = built_tx.sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx); + let commitment_txid = built_tx.txid; + + let mut htlc_sigs = Vec::with_capacity(commitment_tx.htlcs().len()); + for htlc in commitment_tx.htlcs() { + let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, commitment_tx.feerate_per_kw(), self.holder_selected_contest_delay(), htlc, &keys.broadcaster_delayed_payment_key, &keys.revocation_key); + let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys); + let htlc_sighash = hash_to_message!(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, SigHashType::All)[..]); + let holder_htlc_key = match chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key) { + Ok(s) => s, + Err(_) => return Err(()), + }; + htlc_sigs.push(secp_ctx.sign(&htlc_sighash, &holder_htlc_key)); } Ok((commitment_sig, htlc_sigs)) } - fn sign_holder_commitment(&self, holder_commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1) -> Result { + fn sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1) -> Result { let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key); - let counterparty_channel_data = self.accepted_channel_data.as_ref().expect("must accept before signing"); - let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &counterparty_channel_data.counterparty_channel_pubkeys.funding_pubkey); - - Ok(holder_commitment_tx.get_holder_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx)) + let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey); + let sig = commitment_tx.trust().built_transaction().sign(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, secp_ctx); + Ok(sig) } #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))] - fn unsafe_sign_holder_commitment(&self, holder_commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1) -> Result { + fn unsafe_sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1) -> Result { let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key); - let counterparty_channel_pubkeys = &self.accepted_channel_data.as_ref().expect("must accept before signing").counterparty_channel_pubkeys; - let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &counterparty_channel_pubkeys.funding_pubkey); - - Ok(holder_commitment_tx.get_holder_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx)) + let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey); + Ok(commitment_tx.trust().built_transaction().sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx)) } - fn sign_holder_commitment_htlc_transactions(&self, holder_commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1) -> Result>, ()> { - let counterparty_selected_contest_delay = self.accepted_channel_data.as_ref().unwrap().counterparty_selected_contest_delay; - holder_commitment_tx.get_htlc_sigs(&self.htlc_base_key, counterparty_selected_contest_delay, secp_ctx) + fn sign_holder_commitment_htlc_transactions(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1) -> Result, ()> { + let channel_parameters = self.get_channel_parameters(); + let trusted_tx = commitment_tx.trust(); + trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), secp_ctx) } fn sign_justice_transaction(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option, secp_ctx: &Secp256k1) -> Result { @@ -575,8 +574,7 @@ impl ChannelKeys for InMemoryChannelKeys { if closing_tx.output.len() > 2 { return Err(()); } let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key); - let counterparty_channel_data = self.accepted_channel_data.as_ref().expect("must accept before signing"); - let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &counterparty_channel_data.counterparty_channel_pubkeys.funding_pubkey); + let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey); let sighash = hash_to_message!(&bip143::SigHashCache::new(closing_tx) .signature_hash(0, &channel_funding_redeemscript, self.channel_value_satoshis, SigHashType::All)[..]); @@ -588,19 +586,13 @@ impl ChannelKeys for InMemoryChannelKeys { Ok(secp_ctx.sign(&msghash, &self.funding_key)) } - fn on_accept(&mut self, channel_pubkeys: &ChannelPublicKeys, counterparty_selected_contest_delay: u16, holder_selected_contest_delay: u16) { - assert!(self.accepted_channel_data.is_none(), "Already accepted"); - self.accepted_channel_data = Some(AcceptedChannelData { - counterparty_channel_pubkeys: channel_pubkeys.clone(), - counterparty_selected_contest_delay, - holder_selected_contest_delay, - }); + fn ready_channel(&mut self, channel_parameters: &ChannelTransactionParameters) { + assert!(self.channel_parameters.is_none(), "Acceptance already noted"); + assert!(channel_parameters.is_populated(), "Channel parameters must be fully populated"); + self.channel_parameters = Some(channel_parameters.clone()); } } -impl_writeable!(AcceptedChannelData, 0, - { counterparty_channel_pubkeys, counterparty_selected_contest_delay, holder_selected_contest_delay }); - impl Writeable for InMemoryChannelKeys { fn write(&self, writer: &mut W) -> Result<(), Error> { self.funding_key.write(writer)?; @@ -609,7 +601,7 @@ impl Writeable for InMemoryChannelKeys { self.delayed_payment_base_key.write(writer)?; self.htlc_base_key.write(writer)?; self.commitment_seed.write(writer)?; - self.accepted_channel_data.write(writer)?; + self.channel_parameters.write(writer)?; self.channel_value_satoshis.write(writer)?; self.key_derivation_params.0.write(writer)?; self.key_derivation_params.1.write(writer)?; @@ -645,7 +637,7 @@ impl Readable for InMemoryChannelKeys { commitment_seed, channel_value_satoshis, holder_channel_pubkeys, - accepted_channel_data: counterparty_channel_data, + channel_parameters: counterparty_channel_data, key_derivation_params: (params_1, params_2), }) } @@ -825,4 +817,8 @@ impl KeysInterface for KeysManager { sha.input(b"Unique Secure Random Bytes Salt"); Sha256::from_engine(sha).into_inner() } + + fn read_chan_signer(&self, reader: &[u8]) -> Result { + InMemoryChannelKeys::read(&mut std::io::Cursor::new(reader)) + } }