X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;ds=sidebyside;f=lightning%2Fsrc%2Fchain%2Fkeysinterface.rs;h=689a16603743e228ffff64dfba9ea710474fdc43;hb=a19d71d0b2768f2aee747b07be509b6591378e7a;hp=1abf829c87ac38e7330f0af36cea763fcea0df76;hpb=262666ad7fe266004845cd140a3c1923f757fd28;p=rust-lightning diff --git a/lightning/src/chain/keysinterface.rs b/lightning/src/chain/keysinterface.rs index 1abf829c..689a1660 100644 --- a/lightning/src/chain/keysinterface.rs +++ b/lightning/src/chain/keysinterface.rs @@ -12,6 +12,7 @@ use bitcoin::util::bip143; use bitcoin_hashes::{Hash, HashEngine}; use bitcoin_hashes::sha256::HashEngine as Sha256State; use bitcoin_hashes::sha256::Hash as Sha256; +use bitcoin_hashes::sha256d::Hash as Sha256dHash; use bitcoin_hashes::hash160::Hash as Hash160; use secp256k1::key::{SecretKey, PublicKey}; @@ -20,9 +21,11 @@ use secp256k1; use util::byte_utils; use util::logger::Logger; +use util::ser::Writeable; use ln::chan_utils; -use ln::chan_utils::{TxCreationKeys, HTLCOutputInCommitment}; +use ln::chan_utils::{TxCreationKeys, HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys}; +use ln::msgs; use std::sync::Arc; use std::sync::atomic::{AtomicUsize, Ordering}; @@ -94,6 +97,22 @@ pub trait KeysInterface: Send + Sync { /// Set of lightning keys needed to operate a channel as described in BOLT 3. /// +/// Signing services could be implemented on a hardware wallet. In this case, +/// the current ChannelKeys would be a front-end on top of a communication +/// channel connected to your secure device and lightning key material wouldn't +/// reside on a hot server. Nevertheless, a this deployment would still need +/// to trust the ChannelManager to avoid loss of funds as this latest component +/// could ask to sign commitment transaction with HTLCs paying to attacker pubkeys. +/// +/// A more secure iteration would be to use hashlock (or payment points) to pair +/// invoice/incoming HTLCs with outgoing HTLCs to implement a no-trust-ChannelManager +/// at the price of more state and computation on the hardware wallet side. In the future, +/// we are looking forward to design such interface. +/// +/// In any case, ChannelMonitor or fallback watchtowers are always going to be trusted +/// to act, as liveness and breach reply correctness are always going to be hard requirements +/// of LN security model, orthogonal of key management issues. +/// /// If you're implementing a custom signer, you almost certainly want to implement /// Readable/Writable to serialize out a unique reference to this set of keys so /// that you can serialize the full ChannelManager object. @@ -106,9 +125,10 @@ pub trait ChannelKeys : Send { fn funding_key<'a>(&'a self) -> &'a SecretKey; /// Gets the local secret key for blinded revocation pubkey fn revocation_base_key<'a>(&'a self) -> &'a SecretKey; - /// Gets the local secret key used in commitment tx htlc outputs + /// Gets the local secret key used in to_remote output of remote commitment tx + /// (and also as part of obscured commitment number) fn payment_base_key<'a>(&'a self) -> &'a SecretKey; - /// Gets the local secret key used in HTLC tx + /// Gets the local secret key used in HTLC-Success/HTLC-Timeout txn and to_local output fn delayed_payment_base_key<'a>(&'a self) -> &'a SecretKey; /// Gets the local htlc secret key used in commitment tx htlc outputs fn htlc_base_key<'a>(&'a self) -> &'a SecretKey; @@ -122,7 +142,27 @@ pub trait ChannelKeys : Send { /// 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, channel_value_satoshis: u64, channel_funding_script: &Script, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()>; + fn sign_remote_commitment(&self, channel_value_satoshis: u64, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()>; + + /// Create a signature for a (proposed) closing transaction. + /// + /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have + /// chosen to forgo their output as dust. + fn sign_closing_transaction(&self, channel_value_satoshis: u64, channel_funding_redeemscript: &Script, closing_tx: &Transaction, secp_ctx: &Secp256k1) -> Result; + + /// Signs a channel announcement message with our funding key, proving it comes from one + /// of the channel participants. + /// + /// Note that if this fails or is rejected, the channel will not be publicly announced and + /// our counterparty may (though likely will not) close the channel on us for violating the + /// 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. + /// + /// Will be called before any signatures are applied. + fn set_remote_channel_pubkeys(&mut self, channel_points: &ChannelPublicKeys); } #[derive(Clone)] @@ -140,6 +180,8 @@ pub struct InMemoryChannelKeys { pub htlc_base_key: SecretKey, /// Commitment seed pub commitment_seed: [u8; 32], + /// Remote funding pubkey + pub remote_channel_pubkeys: Option, } impl ChannelKeys for InMemoryChannelKeys { @@ -150,10 +192,14 @@ impl ChannelKeys for InMemoryChannelKeys { fn htlc_base_key(&self) -> &SecretKey { &self.htlc_base_key } fn commitment_seed(&self) -> &[u8; 32] { &self.commitment_seed } - - fn sign_remote_commitment(&self, channel_value_satoshis: u64, channel_funding_script: &Script, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()> { + fn sign_remote_commitment(&self, channel_value_satoshis: u64, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()> { if commitment_tx.input.len() != 1 { return Err(()); } - let commitment_sighash = hash_to_message!(&bip143::SighashComponents::new(&commitment_tx).sighash_all(&commitment_tx.input[0], &channel_funding_script, channel_value_satoshis)[..]); + + 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 commitment_sighash = hash_to_message!(&bip143::SighashComponents::new(&commitment_tx).sighash_all(&commitment_tx.input[0], &channel_funding_redeemscript, channel_value_satoshis)[..]); let commitment_sig = secp_ctx.sign(&commitment_sighash, &self.funding_key); let commitment_txid = commitment_tx.txid(); @@ -174,6 +220,26 @@ impl ChannelKeys for InMemoryChannelKeys { Ok((commitment_sig, htlc_sigs)) } + + fn sign_closing_transaction(&self, channel_value_satoshis: u64, channel_funding_redeemscript: &Script, closing_tx: &Transaction, secp_ctx: &Secp256k1) -> Result { + if closing_tx.input.len() != 1 { return Err(()); } + if closing_tx.input[0].witness.len() != 0 { return Err(()); } + if closing_tx.output.len() > 2 { return Err(()); } + + let sighash = hash_to_message!(&bip143::SighashComponents::new(closing_tx) + .sighash_all(&closing_tx.input[0], &channel_funding_redeemscript, channel_value_satoshis)[..]); + Ok(secp_ctx.sign(&sighash, &self.funding_key)) + } + + fn sign_channel_announcement(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1) -> Result { + let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]); + 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()); + } } impl_writeable!(InMemoryChannelKeys, 0, { @@ -182,7 +248,8 @@ impl_writeable!(InMemoryChannelKeys, 0, { payment_base_key, delayed_payment_base_key, htlc_base_key, - commitment_seed + commitment_seed, + remote_channel_pubkeys }); /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key @@ -331,6 +398,7 @@ impl KeysInterface for KeysManager { delayed_payment_base_key, htlc_base_key, commitment_seed, + remote_channel_pubkeys: None, } }