X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fchain%2Fkeysinterface.rs;h=26d1f07c7c43c38fc378d42431ffa2dde190ab92;hb=48d73b3264a034f456e60540e438eb9a6aea14a6;hp=31ed2d15cbcc65507a3919ba3f06ca30966d23e9;hpb=bd2fa43acd54f9e0876d493178679dfcadf7d178;p=rust-lightning diff --git a/lightning/src/chain/keysinterface.rs b/lightning/src/chain/keysinterface.rs index 31ed2d15..26d1f07c 100644 --- a/lightning/src/chain/keysinterface.rs +++ b/lightning/src/chain/keysinterface.rs @@ -69,7 +69,7 @@ pub enum SpendableOutputDescriptor { /// /// To derive the remote_revocation_pubkey provided here (which is used in the witness /// script generation), you must pass the remote revocation_basepoint (which appears in the - /// call to ChannelKeys::set_remote_channel_pubkeys) and the provided per_commitment point + /// call to ChannelKeys::on_accept) 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 @@ -195,10 +195,22 @@ impl Readable for SpendableOutputDescriptor { // 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 { - /// Gets the commitment seed - fn commitment_seed<'a>(&'a self) -> &'a [u8; 32]; + /// Gets the per-commitment point for a specific commitment number + /// + /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards. + fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1) -> PublicKey; + /// Gets the commitment secret for a specific commitment number as part of the revocation process + /// + /// An external signer implementation should error here if the commitment was already signed + /// and should refuse to sign it in the future. + /// + /// May be called more than once for the same index. + /// + /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards. + /// TODO: return a Result so we can signal a validation error + fn release_commitment_secret(&self, idx: u64) -> [u8; 32]; /// Gets the local channel public keys and basepoints - fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys; + fn pubkeys(&self) -> &ChannelPublicKeys; /// Gets arbitrary identifiers describing the set of keys which are provided back to you in /// some SpendableOutputDescriptor types. These should be sufficient to identify this /// ChannelKeys object uniquely and lookup or re-derive its keys. @@ -211,11 +223,12 @@ pub trait ChannelKeys : Send+Clone { // 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_remote_commitment(&self, feerate_per_kw: u32, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()>; + fn sign_remote_commitment(&self, feerate_per_kw: u32, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()>; /// Create a signature for a local commitment transaction. This will only ever be called with /// the same local_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 @@ -241,7 +254,7 @@ pub trait ChannelKeys : Send+Clone { /// (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_local_commitment_htlc_transactions(&self, local_commitment_tx: &LocalCommitmentTransaction, local_csv: u16, secp_ctx: &Secp256k1) -> Result>, ()>; + fn sign_local_commitment_htlc_transactions(&self, local_commitment_tx: &LocalCommitmentTransaction, 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. @@ -261,11 +274,7 @@ pub trait ChannelKeys : Send+Clone { /// htlc holds HTLC elements (hash, timelock) if the output being spent is a HTLC output, thus /// changing the format of the witness script (which is committed to in the BIP 143 /// signatures). - /// - /// on_remote_tx_csv is the relative lock-time that that our counterparty would have to set on - /// their transaction were they to spend the same output. It is included in the witness script - /// and thus committed to in the BIP 143 signature. - fn sign_justice_transaction(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option, on_remote_tx_csv: u16, secp_ctx: &Secp256k1) -> Result; + fn sign_justice_transaction(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option, secp_ctx: &Secp256k1) -> Result; /// Create a signature for a claiming transaction for a HTLC output on a remote commitment /// transaction, either offered or received. @@ -300,11 +309,13 @@ pub trait ChannelKeys : Send+Clone { /// protocol. fn sign_channel_announcement(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1) -> Result; - /// Set the remote channel basepoints. This is done immediately on incoming channels - /// and as soon as the channel is accepted on outgoing channels. + /// Set the remote channel basepoints and remote/local to_self_delay. + /// This is done immediately on incoming channels and as soon as the channel is accepted on outgoing channels. + /// + /// We bind local_to_self_delay late here for API convenience. /// /// Will be called before any signatures are applied. - fn set_remote_channel_pubkeys(&mut self, channel_points: &ChannelPublicKeys); + fn on_accept(&mut self, channel_points: &ChannelPublicKeys, remote_to_self_delay: u16, local_to_self_delay: u16); } /// A trait to describe an object which can get user secrets and key material. @@ -329,6 +340,25 @@ pub trait KeysInterface: Send + Sync { fn get_channel_id(&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 { + /// Remote public keys and base points + remote_channel_pubkeys: ChannelPublicKeys, + /// The to_self_delay value specified by our counterparty and applied on locally-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 local transactions. + remote_to_self_delay: u16, + /// The to_self_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. + local_to_self_delay: u16, +} + #[derive(Clone)] /// A simple implementation of ChannelKeys that just keeps the private keys in memory. pub struct InMemoryChannelKeys { @@ -346,8 +376,8 @@ pub struct InMemoryChannelKeys { pub commitment_seed: [u8; 32], /// Local public keys and basepoints pub(crate) local_channel_pubkeys: ChannelPublicKeys, - /// Remote public keys and base points - pub(crate) remote_channel_pubkeys: Option, + /// Remote public keys and remote/local to_self_delay, populated on channel acceptance + accepted_channel_data: Option, /// The total value of this channel channel_value_satoshis: u64, /// Key derivation parameters @@ -379,7 +409,7 @@ impl InMemoryChannelKeys { commitment_seed, channel_value_satoshis, local_channel_pubkeys, - remote_channel_pubkeys: None, + accepted_channel_data: None, key_derivation_params, } } @@ -400,20 +430,43 @@ impl InMemoryChannelKeys { } } - fn remote_pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { self.remote_channel_pubkeys.as_ref().unwrap() } + /// Remote pubkeys. + /// Will panic if on_accept wasn't called. + pub fn remote_pubkeys(&self) -> &ChannelPublicKeys { &self.accepted_channel_data.as_ref().unwrap().remote_channel_pubkeys } + + /// The to_self_delay value specified by our counterparty and applied on locally-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 local transactions. + /// Will panic if on_accept wasn't called. + pub fn remote_to_self_delay(&self) -> u16 { self.accepted_channel_data.as_ref().unwrap().remote_to_self_delay } + + /// The to_self_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 local_to_self_delay(&self) -> u16 { self.accepted_channel_data.as_ref().unwrap().local_to_self_delay } } impl ChannelKeys for InMemoryChannelKeys { - fn commitment_seed(&self) -> &[u8; 32] { &self.commitment_seed } - fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { &self.local_channel_pubkeys } + fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1) -> PublicKey { + let commitment_secret = SecretKey::from_slice(&chan_utils::build_commitment_secret(&self.commitment_seed, idx)).unwrap(); + PublicKey::from_secret_key(secp_ctx, &commitment_secret) + } + + fn release_commitment_secret(&self, idx: u64) -> [u8; 32] { + chan_utils::build_commitment_secret(&self.commitment_seed, idx) + } + + fn pubkeys(&self) -> &ChannelPublicKeys { &self.local_channel_pubkeys } fn key_derivation_params(&self) -> (u64, u64) { self.key_derivation_params } - fn sign_remote_commitment(&self, feerate_per_kw: u32, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()> { + fn sign_remote_commitment(&self, feerate_per_kw: u32, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()> { if commitment_tx.input.len() != 1 { return Err(()); } let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key); - let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing"); - let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey); + 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.remote_channel_pubkeys.funding_pubkey); let commitment_sighash = hash_to_message!(&bip143::SighashComponents::new(&commitment_tx).sighash_all(&commitment_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]); let commitment_sig = secp_ctx.sign(&commitment_sighash, &self.funding_key); @@ -423,7 +476,7 @@ impl ChannelKeys for InMemoryChannelKeys { 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, to_self_delay, htlc, &keys.a_delayed_payment_key, &keys.revocation_key); + let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, feerate_per_kw, accepted_data.local_to_self_delay, htlc, &keys.a_delayed_payment_key, &keys.revocation_key); let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys); let htlc_sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, htlc.amount_msat / 1000)[..]); let our_htlc_key = match chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key) { @@ -439,8 +492,8 @@ impl ChannelKeys for InMemoryChannelKeys { fn sign_local_commitment(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1) -> Result { let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key); - let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing"); - let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey); + let remote_channel_data = self.accepted_channel_data.as_ref().expect("must accept before signing"); + let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_data.remote_channel_pubkeys.funding_pubkey); Ok(local_commitment_tx.get_local_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx)) } @@ -448,17 +501,18 @@ impl ChannelKeys for InMemoryChannelKeys { #[cfg(test)] fn unsafe_sign_local_commitment(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1) -> Result { let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key); - let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing"); + let remote_channel_pubkeys = &self.accepted_channel_data.as_ref().expect("must accept before signing").remote_channel_pubkeys; let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey); Ok(local_commitment_tx.get_local_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx)) } - fn sign_local_commitment_htlc_transactions(&self, local_commitment_tx: &LocalCommitmentTransaction, local_csv: u16, secp_ctx: &Secp256k1) -> Result>, ()> { + fn sign_local_commitment_htlc_transactions(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1) -> Result>, ()> { + let local_csv = self.accepted_channel_data.as_ref().unwrap().remote_to_self_delay; local_commitment_tx.get_htlc_sigs(&self.htlc_base_key, local_csv, secp_ctx) } - fn sign_justice_transaction(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option, on_remote_tx_csv: u16, secp_ctx: &Secp256k1) -> Result { + fn sign_justice_transaction(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option, secp_ctx: &Secp256k1) -> Result { let revocation_key = match chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key) { Ok(revocation_key) => revocation_key, Err(_) => return Err(()) @@ -483,7 +537,7 @@ impl ChannelKeys for InMemoryChannelKeys { Ok(remote_delayedpubkey) => remote_delayedpubkey, Err(_) => return Err(()) }; - chan_utils::get_revokeable_redeemscript(&revocation_pubkey, on_remote_tx_csv, &remote_delayedpubkey) + chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.local_to_self_delay(), &remote_delayedpubkey) }; let sighash_parts = bip143::SighashComponents::new(&justice_tx); let sighash = hash_to_message!(&sighash_parts.sighash_all(&justice_tx.input[input], &witness_script, amount)[..]); @@ -511,9 +565,9 @@ impl ChannelKeys for InMemoryChannelKeys { if closing_tx.input[0].witness.len() != 0 { return Err(()); } if closing_tx.output.len() > 2 { return Err(()); } - let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing"); let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key); - let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey); + let remote_channel_data = self.accepted_channel_data.as_ref().expect("must accept before signing"); + let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_data.remote_channel_pubkeys.funding_pubkey); let sighash = hash_to_message!(&bip143::SighashComponents::new(closing_tx) .sighash_all(&closing_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]); @@ -525,12 +579,19 @@ impl ChannelKeys for InMemoryChannelKeys { Ok(secp_ctx.sign(&msghash, &self.funding_key)) } - fn set_remote_channel_pubkeys(&mut self, channel_pubkeys: &ChannelPublicKeys) { - assert!(self.remote_channel_pubkeys.is_none(), "Already set remote channel pubkeys"); - self.remote_channel_pubkeys = Some(channel_pubkeys.clone()); + fn on_accept(&mut self, channel_pubkeys: &ChannelPublicKeys, remote_to_self_delay: u16, local_to_self_delay: u16) { + assert!(self.accepted_channel_data.is_none(), "Already accepted"); + self.accepted_channel_data = Some(AcceptedChannelData { + remote_channel_pubkeys: channel_pubkeys.clone(), + remote_to_self_delay, + local_to_self_delay, + }); } } +impl_writeable!(AcceptedChannelData, 0, + { remote_channel_pubkeys, remote_to_self_delay, local_to_self_delay }); + impl Writeable for InMemoryChannelKeys { fn write(&self, writer: &mut W) -> Result<(), Error> { self.funding_key.write(writer)?; @@ -539,7 +600,7 @@ impl Writeable for InMemoryChannelKeys { self.delayed_payment_base_key.write(writer)?; self.htlc_base_key.write(writer)?; self.commitment_seed.write(writer)?; - self.remote_channel_pubkeys.write(writer)?; + self.accepted_channel_data.write(writer)?; self.channel_value_satoshis.write(writer)?; self.key_derivation_params.0.write(writer)?; self.key_derivation_params.1.write(writer)?; @@ -556,7 +617,7 @@ impl Readable for InMemoryChannelKeys { let delayed_payment_base_key = Readable::read(reader)?; let htlc_base_key = Readable::read(reader)?; let commitment_seed = Readable::read(reader)?; - let remote_channel_pubkeys = Readable::read(reader)?; + let remote_channel_data = Readable::read(reader)?; let channel_value_satoshis = Readable::read(reader)?; let secp_ctx = Secp256k1::signing_only(); let local_channel_pubkeys = @@ -575,7 +636,7 @@ impl Readable for InMemoryChannelKeys { commitment_seed, channel_value_satoshis, local_channel_pubkeys, - remote_channel_pubkeys, + accepted_channel_data: remote_channel_data, key_derivation_params: (params_1, params_2), }) }