diff --git a/lightning/src/chain/channelmonitor.rs b/lightning/src/chain/channelmonitor.rs index 92f1a8df45d..cc88a0119fc 100644 --- a/lightning/src/chain/channelmonitor.rs +++ b/lightning/src/chain/channelmonitor.rs @@ -2443,8 +2443,8 @@ impl ChannelMonitorImpl { let secret = self.get_secret(commitment_number).unwrap(); let per_commitment_key = ignore_error!(SecretKey::from_slice(&secret)); let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key); - let revocation_pubkey = ignore_error!(chan_utils::derive_public_revocation_key(&self.secp_ctx, &per_commitment_point, &self.holder_revocation_basepoint)); - let delayed_key = ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, &PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key), &self.counterparty_commitment_params.counterparty_delayed_payment_base_key)); + let revocation_pubkey = chan_utils::derive_public_revocation_key(&self.secp_ctx, &per_commitment_point, &self.holder_revocation_basepoint); + let delayed_key = chan_utils::derive_public_key(&self.secp_ctx, &PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key), &self.counterparty_commitment_params.counterparty_delayed_payment_base_key); let revokeable_redeemscript = chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.counterparty_commitment_params.on_counterparty_tx_csv, &delayed_key); let revokeable_p2wsh = revokeable_redeemscript.to_v0_p2wsh(); @@ -2556,31 +2556,18 @@ impl ChannelMonitorImpl { } else { return (claimable_outpoints, to_counterparty_output_info); }; if let Some(transaction) = tx { - let revokeable_p2wsh_opt = - if let Ok(revocation_pubkey) = chan_utils::derive_public_revocation_key( - &self.secp_ctx, &per_commitment_point, &self.holder_revocation_basepoint) - { - if let Ok(delayed_key) = chan_utils::derive_public_key(&self.secp_ctx, - &per_commitment_point, - &self.counterparty_commitment_params.counterparty_delayed_payment_base_key) - { - Some(chan_utils::get_revokeable_redeemscript(&revocation_pubkey, - self.counterparty_commitment_params.on_counterparty_tx_csv, - &delayed_key).to_v0_p2wsh()) - } else { - debug_assert!(false, "Failed to derive a delayed payment key for a commitment state we accepted"); - None - } - } else { - debug_assert!(false, "Failed to derive a revocation pubkey key for a commitment state we accepted"); - None - }; - if let Some(revokeable_p2wsh) = revokeable_p2wsh_opt { - for (idx, outp) in transaction.output.iter().enumerate() { - if outp.script_pubkey == revokeable_p2wsh { - to_counterparty_output_info = - Some((idx.try_into().expect("Can't have > 2^32 outputs"), outp.value)); - } + let revocation_pubkey = chan_utils::derive_public_revocation_key( + &self.secp_ctx, &per_commitment_point, &self.holder_revocation_basepoint); + let delayed_key = chan_utils::derive_public_key(&self.secp_ctx, + &per_commitment_point, + &self.counterparty_commitment_params.counterparty_delayed_payment_base_key); + let revokeable_p2wsh = chan_utils::get_revokeable_redeemscript(&revocation_pubkey, + self.counterparty_commitment_params.on_counterparty_tx_csv, + &delayed_key).to_v0_p2wsh(); + for (idx, outp) in transaction.output.iter().enumerate() { + if outp.script_pubkey == revokeable_p2wsh { + to_counterparty_output_info = + Some((idx.try_into().expect("Can't have > 2^32 outputs"), outp.value)); } } } diff --git a/lightning/src/chain/keysinterface.rs b/lightning/src/chain/keysinterface.rs index 9f81976906c..db1c6e94371 100644 --- a/lightning/src/chain/keysinterface.rs +++ b/lightning/src/chain/keysinterface.rs @@ -655,8 +655,7 @@ impl InMemorySigner { if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); } if spend_tx.input[input_idx].sequence.0 != descriptor.to_self_delay as u32 { return Err(()); } - let delayed_payment_key = chan_utils::derive_private_key(&secp_ctx, &descriptor.per_commitment_point, &self.delayed_payment_base_key) - .expect("We constructed the payment_base_key, so we can only fail here if the RNG is busted."); + let delayed_payment_key = chan_utils::derive_private_key(&secp_ctx, &descriptor.per_commitment_point, &self.delayed_payment_base_key); let delayed_payment_pubkey = PublicKey::from_secret_key(&secp_ctx, &delayed_payment_key); let witness_script = chan_utils::get_revokeable_redeemscript(&descriptor.revocation_pubkey, descriptor.to_self_delay, &delayed_payment_pubkey); let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]); @@ -710,7 +709,7 @@ impl BaseSign for InMemorySigner { let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, self.opt_anchors(), &keys); let htlc_sighashtype = if self.opt_anchors() { EcdsaSighashType::SinglePlusAnyoneCanPay } else { EcdsaSighashType::All }; let htlc_sighash = hash_to_message!(&sighash::SighashCache::new(&htlc_tx).segwit_signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype).unwrap()[..]); - let holder_htlc_key = chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key).map_err(|_| ())?; + let holder_htlc_key = chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key); htlc_sigs.push(sign(secp_ctx, &htlc_sighash, &holder_htlc_key)); } @@ -743,11 +742,11 @@ impl BaseSign for InMemorySigner { } fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1) -> Result { - let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key).map_err(|_| ())?; + let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key); let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key); - let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint).map_err(|_| ())?; + let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint); let witness_script = { - let counterparty_delayedpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().delayed_payment_basepoint).map_err(|_| ())?; + let counterparty_delayedpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().delayed_payment_basepoint); chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.holder_selected_contest_delay(), &counterparty_delayedpubkey) }; let mut sighash_parts = sighash::SighashCache::new(justice_tx); @@ -756,12 +755,12 @@ impl BaseSign for InMemorySigner { } fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1) -> Result { - let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key).map_err(|_| ())?; + let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key); let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key); - let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint).map_err(|_| ())?; + let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint); let witness_script = { - let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint).map_err(|_| ())?; - let holder_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint).map_err(|_| ())?; + let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint); + let holder_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint); chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.opt_anchors(), &counterparty_htlcpubkey, &holder_htlcpubkey, &revocation_pubkey) }; let mut sighash_parts = sighash::SighashCache::new(justice_tx); @@ -770,19 +769,14 @@ impl BaseSign for InMemorySigner { } fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1) -> Result { - if let Ok(htlc_key) = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key) { - let witness_script = if let Ok(revocation_pubkey) = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint) { - if let Ok(counterparty_htlcpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint) { - if let Ok(htlcpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint) { - chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.opt_anchors(), &counterparty_htlcpubkey, &htlcpubkey, &revocation_pubkey) - } else { return Err(()) } - } else { return Err(()) } - } else { return Err(()) }; - let mut sighash_parts = sighash::SighashCache::new(htlc_tx); - let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]); - return Ok(sign(secp_ctx, &sighash, &htlc_key)) - } - Err(()) + let htlc_key = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key); + let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint); + let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint); + let htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint); + let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.opt_anchors(), &counterparty_htlcpubkey, &htlcpubkey, &revocation_pubkey); + let mut sighash_parts = sighash::SighashCache::new(htlc_tx); + let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]); + Ok(sign(secp_ctx, &sighash, &htlc_key)) } fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1) -> Result { diff --git a/lightning/src/chain/package.rs b/lightning/src/chain/package.rs index 1307ad0eb3f..cf92df29521 100644 --- a/lightning/src/chain/package.rs +++ b/lightning/src/chain/package.rs @@ -381,57 +381,53 @@ impl PackageSolvingData { fn finalize_input(&self, bumped_tx: &mut Transaction, i: usize, onchain_handler: &mut OnchainTxHandler) -> bool { match self { PackageSolvingData::RevokedOutput(ref outp) => { - if let Ok(chan_keys) = TxCreationKeys::derive_new(&onchain_handler.secp_ctx, &outp.per_commitment_point, &outp.counterparty_delayed_payment_base_key, &outp.counterparty_htlc_base_key, &onchain_handler.signer.pubkeys().revocation_basepoint, &onchain_handler.signer.pubkeys().htlc_basepoint) { - let witness_script = chan_utils::get_revokeable_redeemscript(&chan_keys.revocation_key, outp.on_counterparty_tx_csv, &chan_keys.broadcaster_delayed_payment_key); - //TODO: should we panic on signer failure ? - if let Ok(sig) = onchain_handler.signer.sign_justice_revoked_output(&bumped_tx, i, outp.amount, &outp.per_commitment_key, &onchain_handler.secp_ctx) { - let mut ser_sig = sig.serialize_der().to_vec(); - ser_sig.push(EcdsaSighashType::All as u8); - bumped_tx.input[i].witness.push(ser_sig); - bumped_tx.input[i].witness.push(vec!(1)); - bumped_tx.input[i].witness.push(witness_script.clone().into_bytes()); - } else { return false; } - } + let chan_keys = TxCreationKeys::derive_new(&onchain_handler.secp_ctx, &outp.per_commitment_point, &outp.counterparty_delayed_payment_base_key, &outp.counterparty_htlc_base_key, &onchain_handler.signer.pubkeys().revocation_basepoint, &onchain_handler.signer.pubkeys().htlc_basepoint); + let witness_script = chan_utils::get_revokeable_redeemscript(&chan_keys.revocation_key, outp.on_counterparty_tx_csv, &chan_keys.broadcaster_delayed_payment_key); + //TODO: should we panic on signer failure ? + if let Ok(sig) = onchain_handler.signer.sign_justice_revoked_output(&bumped_tx, i, outp.amount, &outp.per_commitment_key, &onchain_handler.secp_ctx) { + let mut ser_sig = sig.serialize_der().to_vec(); + ser_sig.push(EcdsaSighashType::All as u8); + bumped_tx.input[i].witness.push(ser_sig); + bumped_tx.input[i].witness.push(vec!(1)); + bumped_tx.input[i].witness.push(witness_script.clone().into_bytes()); + } else { return false; } }, PackageSolvingData::RevokedHTLCOutput(ref outp) => { - if let Ok(chan_keys) = TxCreationKeys::derive_new(&onchain_handler.secp_ctx, &outp.per_commitment_point, &outp.counterparty_delayed_payment_base_key, &outp.counterparty_htlc_base_key, &onchain_handler.signer.pubkeys().revocation_basepoint, &onchain_handler.signer.pubkeys().htlc_basepoint) { - let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&outp.htlc, onchain_handler.opt_anchors(), &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key); - //TODO: should we panic on signer failure ? - if let Ok(sig) = onchain_handler.signer.sign_justice_revoked_htlc(&bumped_tx, i, outp.amount, &outp.per_commitment_key, &outp.htlc, &onchain_handler.secp_ctx) { - let mut ser_sig = sig.serialize_der().to_vec(); - ser_sig.push(EcdsaSighashType::All as u8); - bumped_tx.input[i].witness.push(ser_sig); - bumped_tx.input[i].witness.push(chan_keys.revocation_key.clone().serialize().to_vec()); - bumped_tx.input[i].witness.push(witness_script.clone().into_bytes()); - } else { return false; } - } + let chan_keys = TxCreationKeys::derive_new(&onchain_handler.secp_ctx, &outp.per_commitment_point, &outp.counterparty_delayed_payment_base_key, &outp.counterparty_htlc_base_key, &onchain_handler.signer.pubkeys().revocation_basepoint, &onchain_handler.signer.pubkeys().htlc_basepoint); + let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&outp.htlc, onchain_handler.opt_anchors(), &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key); + //TODO: should we panic on signer failure ? + if let Ok(sig) = onchain_handler.signer.sign_justice_revoked_htlc(&bumped_tx, i, outp.amount, &outp.per_commitment_key, &outp.htlc, &onchain_handler.secp_ctx) { + let mut ser_sig = sig.serialize_der().to_vec(); + ser_sig.push(EcdsaSighashType::All as u8); + bumped_tx.input[i].witness.push(ser_sig); + bumped_tx.input[i].witness.push(chan_keys.revocation_key.clone().serialize().to_vec()); + bumped_tx.input[i].witness.push(witness_script.clone().into_bytes()); + } else { return false; } }, PackageSolvingData::CounterpartyOfferedHTLCOutput(ref outp) => { - if let Ok(chan_keys) = TxCreationKeys::derive_new(&onchain_handler.secp_ctx, &outp.per_commitment_point, &outp.counterparty_delayed_payment_base_key, &outp.counterparty_htlc_base_key, &onchain_handler.signer.pubkeys().revocation_basepoint, &onchain_handler.signer.pubkeys().htlc_basepoint) { - let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&outp.htlc, onchain_handler.opt_anchors(), &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key); - - if let Ok(sig) = onchain_handler.signer.sign_counterparty_htlc_transaction(&bumped_tx, i, &outp.htlc.amount_msat / 1000, &outp.per_commitment_point, &outp.htlc, &onchain_handler.secp_ctx) { - let mut ser_sig = sig.serialize_der().to_vec(); - ser_sig.push(EcdsaSighashType::All as u8); - bumped_tx.input[i].witness.push(ser_sig); - bumped_tx.input[i].witness.push(outp.preimage.0.to_vec()); - bumped_tx.input[i].witness.push(witness_script.clone().into_bytes()); - } + let chan_keys = TxCreationKeys::derive_new(&onchain_handler.secp_ctx, &outp.per_commitment_point, &outp.counterparty_delayed_payment_base_key, &outp.counterparty_htlc_base_key, &onchain_handler.signer.pubkeys().revocation_basepoint, &onchain_handler.signer.pubkeys().htlc_basepoint); + let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&outp.htlc, onchain_handler.opt_anchors(), &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key); + + if let Ok(sig) = onchain_handler.signer.sign_counterparty_htlc_transaction(&bumped_tx, i, &outp.htlc.amount_msat / 1000, &outp.per_commitment_point, &outp.htlc, &onchain_handler.secp_ctx) { + let mut ser_sig = sig.serialize_der().to_vec(); + ser_sig.push(EcdsaSighashType::All as u8); + bumped_tx.input[i].witness.push(ser_sig); + bumped_tx.input[i].witness.push(outp.preimage.0.to_vec()); + bumped_tx.input[i].witness.push(witness_script.clone().into_bytes()); } }, PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => { - if let Ok(chan_keys) = TxCreationKeys::derive_new(&onchain_handler.secp_ctx, &outp.per_commitment_point, &outp.counterparty_delayed_payment_base_key, &outp.counterparty_htlc_base_key, &onchain_handler.signer.pubkeys().revocation_basepoint, &onchain_handler.signer.pubkeys().htlc_basepoint) { - let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&outp.htlc, onchain_handler.opt_anchors(), &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key); - - bumped_tx.lock_time = PackedLockTime(outp.htlc.cltv_expiry); // Right now we don't aggregate time-locked transaction, if we do we should set lock_time before to avoid breaking hash computation - if let Ok(sig) = onchain_handler.signer.sign_counterparty_htlc_transaction(&bumped_tx, i, &outp.htlc.amount_msat / 1000, &outp.per_commitment_point, &outp.htlc, &onchain_handler.secp_ctx) { - let mut ser_sig = sig.serialize_der().to_vec(); - ser_sig.push(EcdsaSighashType::All as u8); - bumped_tx.input[i].witness.push(ser_sig); - // Due to BIP146 (MINIMALIF) this must be a zero-length element to relay. - bumped_tx.input[i].witness.push(vec![]); - bumped_tx.input[i].witness.push(witness_script.clone().into_bytes()); - } + let chan_keys = TxCreationKeys::derive_new(&onchain_handler.secp_ctx, &outp.per_commitment_point, &outp.counterparty_delayed_payment_base_key, &outp.counterparty_htlc_base_key, &onchain_handler.signer.pubkeys().revocation_basepoint, &onchain_handler.signer.pubkeys().htlc_basepoint); + let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&outp.htlc, onchain_handler.opt_anchors(), &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key); + + bumped_tx.lock_time = PackedLockTime(outp.htlc.cltv_expiry); // Right now we don't aggregate time-locked transaction, if we do we should set lock_time before to avoid breaking hash computation + if let Ok(sig) = onchain_handler.signer.sign_counterparty_htlc_transaction(&bumped_tx, i, &outp.htlc.amount_msat / 1000, &outp.per_commitment_point, &outp.htlc, &onchain_handler.secp_ctx) { + let mut ser_sig = sig.serialize_der().to_vec(); + ser_sig.push(EcdsaSighashType::All as u8); + bumped_tx.input[i].witness.push(ser_sig); + // Due to BIP146 (MINIMALIF) this must be a zero-length element to relay. + bumped_tx.input[i].witness.push(vec![]); + bumped_tx.input[i].witness.push(witness_script.clone().into_bytes()); } }, _ => { panic!("API Error!"); } diff --git a/lightning/src/ln/chan_utils.rs b/lightning/src/ln/chan_utils.rs index 3a6e81e6399..b5b9d2ee77f 100644 --- a/lightning/src/ln/chan_utils.rs +++ b/lightning/src/ln/chan_utils.rs @@ -28,7 +28,6 @@ use crate::util::{byte_utils, transaction_utils}; use bitcoin::hash_types::WPubkeyHash; use bitcoin::secp256k1::{SecretKey, PublicKey, Scalar}; use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature, Message}; -use bitcoin::secp256k1::Error as SecpError; use bitcoin::{PackedLockTime, secp256k1, Sequence, Witness}; use crate::io; @@ -316,32 +315,29 @@ impl Readable for CounterpartyCommitmentSecrets { /// Derives a per-commitment-transaction private key (eg an htlc key or delayed_payment key) /// from the base secret and the per_commitment_point. -/// -/// Note that this is infallible iff we trust that at least one of the two input keys are randomly -/// generated (ie our own). -pub fn derive_private_key(secp_ctx: &Secp256k1, per_commitment_point: &PublicKey, base_secret: &SecretKey) -> Result { +pub fn derive_private_key(secp_ctx: &Secp256k1, per_commitment_point: &PublicKey, base_secret: &SecretKey) -> SecretKey { let mut sha = Sha256::engine(); sha.input(&per_commitment_point.serialize()); sha.input(&PublicKey::from_secret_key(&secp_ctx, &base_secret).serialize()); let res = Sha256::from_engine(sha).into_inner(); base_secret.clone().add_tweak(&Scalar::from_be_bytes(res).unwrap()) + .expect("Addition only fails if the tweak is the inverse of the key. This is not possible when the tweak contains the hash of the key.") } /// Derives a per-commitment-transaction public key (eg an htlc key or a delayed_payment key) /// from the base point and the per_commitment_key. This is the public equivalent of /// derive_private_key - using only public keys to derive a public key instead of private keys. -/// -/// Note that this is infallible iff we trust that at least one of the two input keys are randomly -/// generated (ie our own). -pub fn derive_public_key(secp_ctx: &Secp256k1, per_commitment_point: &PublicKey, base_point: &PublicKey) -> Result { +pub fn derive_public_key(secp_ctx: &Secp256k1, per_commitment_point: &PublicKey, base_point: &PublicKey) -> PublicKey { let mut sha = Sha256::engine(); sha.input(&per_commitment_point.serialize()); sha.input(&base_point.serialize()); let res = Sha256::from_engine(sha).into_inner(); - let hashkey = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&res)?); + let hashkey = PublicKey::from_secret_key(&secp_ctx, + &SecretKey::from_slice(&res).expect("Hashes should always be valid keys unless SHA-256 is broken")); base_point.combine(&hashkey) + .expect("Addition only fails if the tweak is the inverse of the key. This is not possible when the tweak contains the hash of the key.") } /// Derives a per-commitment-transaction revocation key from its constituent parts. @@ -350,10 +346,9 @@ pub fn derive_public_key(secp_ctx: &Secp256k1, per_com /// commitment transaction, thus per_commitment_secret always come from cheater /// and revocation_base_secret always come from punisher, which is the broadcaster /// of the transaction spending with this key knowledge. -/// -/// Note that this is infallible iff we trust that at least one of the two input keys are randomly -/// generated (ie our own). -pub fn derive_private_revocation_key(secp_ctx: &Secp256k1, per_commitment_secret: &SecretKey, countersignatory_revocation_base_secret: &SecretKey) -> Result { +pub fn derive_private_revocation_key(secp_ctx: &Secp256k1, + per_commitment_secret: &SecretKey, countersignatory_revocation_base_secret: &SecretKey) +-> SecretKey { let countersignatory_revocation_base_point = PublicKey::from_secret_key(&secp_ctx, &countersignatory_revocation_base_secret); let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret); @@ -372,9 +367,12 @@ pub fn derive_private_revocation_key(secp_ctx: &Secp256k1 Sha256::from_engine(sha).into_inner() }; - let countersignatory_contrib = countersignatory_revocation_base_secret.clone().mul_tweak(&Scalar::from_be_bytes(rev_append_commit_hash_key).unwrap())?; - let broadcaster_contrib = per_commitment_secret.clone().mul_tweak(&Scalar::from_be_bytes(commit_append_rev_hash_key).unwrap())?; + let countersignatory_contrib = countersignatory_revocation_base_secret.clone().mul_tweak(&Scalar::from_be_bytes(rev_append_commit_hash_key).unwrap()) + .expect("Multiplying a secret key by a hash is expected to never fail per secp256k1 docs"); + let broadcaster_contrib = per_commitment_secret.clone().mul_tweak(&Scalar::from_be_bytes(commit_append_rev_hash_key).unwrap()) + .expect("Multiplying a secret key by a hash is expected to never fail per secp256k1 docs"); countersignatory_contrib.add_tweak(&Scalar::from_be_bytes(broadcaster_contrib.secret_bytes()).unwrap()) + .expect("Addition only fails if the tweak is the inverse of the key. This is not possible when the tweak commits to the key.") } /// Derives a per-commitment-transaction revocation public key from its constituent parts. This is @@ -388,7 +386,9 @@ pub fn derive_private_revocation_key(secp_ctx: &Secp256k1 /// /// Note that this is infallible iff we trust that at least one of the two input keys are randomly /// generated (ie our own). -pub fn derive_public_revocation_key(secp_ctx: &Secp256k1, per_commitment_point: &PublicKey, countersignatory_revocation_base_point: &PublicKey) -> Result { +pub fn derive_public_revocation_key(secp_ctx: &Secp256k1, + per_commitment_point: &PublicKey, countersignatory_revocation_base_point: &PublicKey) +-> PublicKey { let rev_append_commit_hash_key = { let mut sha = Sha256::engine(); sha.input(&countersignatory_revocation_base_point.serialize()); @@ -404,9 +404,12 @@ pub fn derive_public_revocation_key(secp_ctx: &Secp2 Sha256::from_engine(sha).into_inner() }; - let countersignatory_contrib = countersignatory_revocation_base_point.clone().mul_tweak(&secp_ctx, &Scalar::from_be_bytes(rev_append_commit_hash_key).unwrap())?; - let broadcaster_contrib = per_commitment_point.clone().mul_tweak(&secp_ctx, &Scalar::from_be_bytes(commit_append_rev_hash_key).unwrap())?; + let countersignatory_contrib = countersignatory_revocation_base_point.clone().mul_tweak(&secp_ctx, &Scalar::from_be_bytes(rev_append_commit_hash_key).unwrap()) + .expect("Multiplying a valid public key by a hash is expected to never fail per secp256k1 docs"); + let broadcaster_contrib = per_commitment_point.clone().mul_tweak(&secp_ctx, &Scalar::from_be_bytes(commit_append_rev_hash_key).unwrap()) + .expect("Multiplying a valid public key by a hash is expected to never fail per secp256k1 docs"); countersignatory_contrib.combine(&broadcaster_contrib) + .expect("Addition only fails if the tweak is the inverse of the key. This is not possible when the tweak commits to the key.") } /// The set of public keys which are used in the creation of one commitment transaction. @@ -479,19 +482,19 @@ impl_writeable_tlv_based!(ChannelPublicKeys, { impl TxCreationKeys { /// Create per-state keys from channel base points and the per-commitment point. /// Key set is asymmetric and can't be used as part of counter-signatory set of transactions. - pub fn derive_new(secp_ctx: &Secp256k1, per_commitment_point: &PublicKey, broadcaster_delayed_payment_base: &PublicKey, broadcaster_htlc_base: &PublicKey, countersignatory_revocation_base: &PublicKey, countersignatory_htlc_base: &PublicKey) -> Result { - Ok(TxCreationKeys { + pub fn derive_new(secp_ctx: &Secp256k1, per_commitment_point: &PublicKey, broadcaster_delayed_payment_base: &PublicKey, broadcaster_htlc_base: &PublicKey, countersignatory_revocation_base: &PublicKey, countersignatory_htlc_base: &PublicKey) -> TxCreationKeys { + TxCreationKeys { per_commitment_point: per_commitment_point.clone(), - revocation_key: derive_public_revocation_key(&secp_ctx, &per_commitment_point, &countersignatory_revocation_base)?, - broadcaster_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_htlc_base)?, - countersignatory_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &countersignatory_htlc_base)?, - broadcaster_delayed_payment_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_delayed_payment_base)?, - }) + revocation_key: derive_public_revocation_key(&secp_ctx, &per_commitment_point, &countersignatory_revocation_base), + broadcaster_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_htlc_base), + countersignatory_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &countersignatory_htlc_base), + broadcaster_delayed_payment_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_delayed_payment_base), + } } /// Generate per-state keys from channel static keys. /// Key set is asymmetric and can't be used as part of counter-signatory set of transactions. - pub fn from_channel_static_keys(per_commitment_point: &PublicKey, broadcaster_keys: &ChannelPublicKeys, countersignatory_keys: &ChannelPublicKeys, secp_ctx: &Secp256k1) -> Result { + pub fn from_channel_static_keys(per_commitment_point: &PublicKey, broadcaster_keys: &ChannelPublicKeys, countersignatory_keys: &ChannelPublicKeys, secp_ctx: &Secp256k1) -> TxCreationKeys { TxCreationKeys::derive_new( &secp_ctx, &per_commitment_point, @@ -1446,7 +1449,7 @@ impl CommitmentTransaction { pub fn verify(&self, channel_parameters: &DirectedChannelTransactionParameters, broadcaster_keys: &ChannelPublicKeys, countersignatory_keys: &ChannelPublicKeys, secp_ctx: &Secp256k1) -> Result { // This is the only field of the key cache that we trust let per_commitment_point = self.keys.per_commitment_point; - let keys = TxCreationKeys::from_channel_static_keys(&per_commitment_point, broadcaster_keys, countersignatory_keys, secp_ctx).unwrap(); + let keys = TxCreationKeys::from_channel_static_keys(&per_commitment_point, broadcaster_keys, countersignatory_keys, secp_ctx); if keys != self.keys { return Err(()); } @@ -1506,7 +1509,7 @@ impl<'a> TrustedCommitmentTransaction<'a> { let keys = &inner.keys; let txid = inner.built.txid; let mut ret = Vec::with_capacity(inner.htlcs.len()); - let holder_htlc_key = derive_private_key(secp_ctx, &inner.keys.per_commitment_point, htlc_base_key).map_err(|_| ())?; + let holder_htlc_key = derive_private_key(secp_ctx, &inner.keys.per_commitment_point, htlc_base_key); for this_htlc in inner.htlcs.iter() { assert!(this_htlc.transaction_output_index.is_some()); @@ -1625,7 +1628,7 @@ mod tests { let htlc_basepoint = &signer.pubkeys().htlc_basepoint; let holder_pubkeys = signer.pubkeys(); let counterparty_pubkeys = counterparty_signer.pubkeys(); - let keys = TxCreationKeys::derive_new(&secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint).unwrap(); + let keys = TxCreationKeys::derive_new(&secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint); let mut channel_parameters = ChannelTransactionParameters { holder_pubkeys: holder_pubkeys.clone(), holder_selected_contest_delay: 0, diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs index 5cc4f4a364b..dcbaa771f93 100644 --- a/lightning/src/ln/channel.rs +++ b/lightning/src/ln/channel.rs @@ -1749,27 +1749,27 @@ impl Channel { /// our counterparty!) /// The result is a transaction which we can revoke broadcastership of (ie a "local" transaction) /// TODO Some magic rust shit to compile-time check this? - fn build_holder_transaction_keys(&self, commitment_number: u64) -> Result { + fn build_holder_transaction_keys(&self, commitment_number: u64) -> TxCreationKeys { let per_commitment_point = self.holder_signer.get_per_commitment_point(commitment_number, &self.secp_ctx); let delayed_payment_base = &self.get_holder_pubkeys().delayed_payment_basepoint; let htlc_basepoint = &self.get_holder_pubkeys().htlc_basepoint; let counterparty_pubkeys = self.get_counterparty_pubkeys(); - Ok(secp_check!(TxCreationKeys::derive_new(&self.secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint), "Local tx keys generation got bogus keys".to_owned())) + TxCreationKeys::derive_new(&self.secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint) } #[inline] /// Creates a set of keys for build_commitment_transaction to generate a transaction which we /// will sign and send to our counterparty. /// If an Err is returned, it is a ChannelError::Close (for get_outbound_funding_created) - fn build_remote_transaction_keys(&self) -> Result { + fn build_remote_transaction_keys(&self) -> TxCreationKeys { //TODO: Ensure that the payment_key derived here ends up in the library users' wallet as we //may see payments to it! let revocation_basepoint = &self.get_holder_pubkeys().revocation_basepoint; let htlc_basepoint = &self.get_holder_pubkeys().htlc_basepoint; let counterparty_pubkeys = self.get_counterparty_pubkeys(); - Ok(secp_check!(TxCreationKeys::derive_new(&self.secp_ctx, &self.counterparty_cur_commitment_point.unwrap(), &counterparty_pubkeys.delayed_payment_basepoint, &counterparty_pubkeys.htlc_basepoint, revocation_basepoint, htlc_basepoint), "Remote tx keys generation got bogus keys".to_owned())) + TxCreationKeys::derive_new(&self.secp_ctx, &self.counterparty_cur_commitment_point.unwrap(), &counterparty_pubkeys.delayed_payment_basepoint, &counterparty_pubkeys.htlc_basepoint, revocation_basepoint, htlc_basepoint) } /// Gets the redeemscript for the funding transaction output (ie the funding transaction output @@ -2157,7 +2157,7 @@ impl Channel { fn funding_created_signature(&mut self, sig: &Signature, logger: &L) -> Result<(Txid, CommitmentTransaction, Signature), ChannelError> where L::Target: Logger { let funding_script = self.get_funding_redeemscript(); - let keys = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number)?; + let keys = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number); let initial_commitment_tx = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &keys, true, false, logger).tx; { let trusted_tx = initial_commitment_tx.trust(); @@ -2171,7 +2171,7 @@ impl Channel { secp_check!(self.secp_ctx.verify_ecdsa(&sighash, &sig, self.counterparty_funding_pubkey()), "Invalid funding_created signature from peer".to_owned()); } - let counterparty_keys = self.build_remote_transaction_keys()?; + let counterparty_keys = self.build_remote_transaction_keys(); let counterparty_initial_commitment_tx = self.build_commitment_transaction(self.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).tx; let counterparty_trusted_tx = counterparty_initial_commitment_tx.trust(); @@ -2285,7 +2285,7 @@ impl Channel { let funding_script = self.get_funding_redeemscript(); - let counterparty_keys = self.build_remote_transaction_keys()?; + let counterparty_keys = self.build_remote_transaction_keys(); let counterparty_initial_commitment_tx = self.build_commitment_transaction(self.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).tx; let counterparty_trusted_tx = counterparty_initial_commitment_tx.trust(); let counterparty_initial_bitcoin_tx = counterparty_trusted_tx.built_transaction(); @@ -2293,7 +2293,7 @@ impl Channel { log_trace!(logger, "Initial counterparty tx for channel {} is: txid {} tx {}", log_bytes!(self.channel_id()), counterparty_initial_bitcoin_tx.txid, encode::serialize_hex(&counterparty_initial_bitcoin_tx.transaction)); - let holder_signer = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number)?; + let holder_signer = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number); let initial_commitment_tx = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &holder_signer, true, false, logger).tx; { let trusted_tx = initial_commitment_tx.trust(); @@ -2959,7 +2959,7 @@ impl Channel { let funding_script = self.get_funding_redeemscript(); - let keys = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number).map_err(|e| (None, e))?; + let keys = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number); let commitment_stats = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &keys, true, false, logger); let commitment_txid = { @@ -3551,7 +3551,7 @@ impl Channel { // Before proposing a feerate update, check that we can actually afford the new fee. let inbound_stats = self.get_inbound_pending_htlc_stats(Some(feerate_per_kw)); let outbound_stats = self.get_outbound_pending_htlc_stats(Some(feerate_per_kw)); - let keys = if let Ok(keys) = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number) { keys } else { return None; }; + let keys = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number); let commitment_stats = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &keys, true, true, logger); let buffer_fee_msat = Channel::::commit_tx_fee_sat(feerate_per_kw, commitment_stats.num_nondust_htlcs + outbound_stats.on_holder_tx_holding_cell_htlcs_count as usize + CONCURRENT_INBOUND_HTLC_FEE_BUFFER as usize, self.opt_anchors()) * 1000; let holder_balance_msat = commitment_stats.local_balance_msat - outbound_stats.holding_cell_msat; @@ -5221,7 +5221,7 @@ impl Channel { /// If an Err is returned, it is a ChannelError::Close (for get_outbound_funding_created) fn get_outbound_funding_created_signature(&mut self, logger: &L) -> Result where L::Target: Logger { - let counterparty_keys = self.build_remote_transaction_keys()?; + let counterparty_keys = self.build_remote_transaction_keys(); let counterparty_initial_commitment_tx = self.build_commitment_transaction(self.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).tx; Ok(self.holder_signer.sign_counterparty_commitment(&counterparty_initial_commitment_tx, Vec::new(), &self.secp_ctx) .map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed".to_owned()))?.0) @@ -5522,7 +5522,7 @@ impl Channel { return Err(ChannelError::Ignore(format!("Cannot send value that would put us over the max HTLC value in flight our peer will accept ({})", self.counterparty_max_htlc_value_in_flight_msat))); } - let keys = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number)?; + let keys = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number); let commitment_stats = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &keys, true, true, logger); if !self.is_outbound() { // Check that we won't violate the remote channel reserve by adding this HTLC. @@ -5714,7 +5714,7 @@ impl Channel { /// Only fails in case of bad keys. Used for channel_reestablish commitment_signed generation /// when we shouldn't change HTLC/channel state. fn send_commitment_no_state_update(&self, logger: &L) -> Result<(msgs::CommitmentSigned, (Txid, Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)>)), ChannelError> where L::Target: Logger { - let counterparty_keys = self.build_remote_transaction_keys()?; + let counterparty_keys = self.build_remote_transaction_keys(); let commitment_stats = self.build_commitment_transaction(self.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, true, logger); let counterparty_commitment_txid = commitment_stats.tx.trust().txid(); let (signature, htlc_signatures); @@ -7309,7 +7309,7 @@ mod tests { let per_commitment_secret = SecretKey::from_slice(&hex::decode("1f1e1d1c1b1a191817161514131211100f0e0d0c0b0a09080706050403020100").unwrap()[..]).unwrap(); let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret); let htlc_basepoint = &chan.holder_signer.pubkeys().htlc_basepoint; - let keys = TxCreationKeys::derive_new(&secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint).unwrap(); + let keys = TxCreationKeys::derive_new(&secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint); macro_rules! test_commitment { ( $counterparty_sig_hex: expr, $sig_hex: expr, $tx_hex: expr, $($remain:tt)* ) => { @@ -7962,16 +7962,16 @@ mod tests { let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret); assert_eq!(per_commitment_point.serialize()[..], hex::decode("025f7117a78150fe2ef97db7cfc83bd57b2e2c0d0dd25eaf467a4a1c2a45ce1486").unwrap()[..]); - assert_eq!(chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &base_point).unwrap().serialize()[..], + assert_eq!(chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &base_point).serialize()[..], hex::decode("0235f2dbfaa89b57ec7b055afe29849ef7ddfeb1cefdb9ebdc43f5494984db29e5").unwrap()[..]); - assert_eq!(chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &base_secret).unwrap(), + assert_eq!(chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &base_secret), SecretKey::from_slice(&hex::decode("cbced912d3b21bf196a766651e436aff192362621ce317704ea2f75d87e7be0f").unwrap()[..]).unwrap()); - assert_eq!(chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &base_point).unwrap().serialize()[..], + assert_eq!(chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &base_point).serialize()[..], hex::decode("02916e326636d19c33f13e8c0c3a03dd157f332f3e99c317c141dd865eb01f8ff0").unwrap()[..]); - assert_eq!(chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_secret, &base_secret).unwrap(), + assert_eq!(chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_secret, &base_secret), SecretKey::from_slice(&hex::decode("d09ffff62ddb2297ab000cc85bcb4283fdeb6aa052affbc9dddcf33b61078110").unwrap()[..]).unwrap()); } diff --git a/lightning/src/ln/functional_tests.rs b/lightning/src/ln/functional_tests.rs index d8dcb013ef5..d2f055dd5ec 100644 --- a/lightning/src/ln/functional_tests.rs +++ b/lightning/src/ln/functional_tests.rs @@ -705,7 +705,7 @@ fn test_update_fee_that_funder_cannot_afford() { // Assemble the set of keys we can use for signatures for our commitment_signed message. let commit_tx_keys = chan_utils::TxCreationKeys::derive_new(&secp_ctx, &remote_point, &remote_delayed_payment_basepoint, - &remote_htlc_basepoint, &local_revocation_basepoint, &local_htlc_basepoint).unwrap(); + &remote_htlc_basepoint, &local_revocation_basepoint, &local_htlc_basepoint); let res = { let local_chan_lock = nodes[0].node.channel_state.lock().unwrap(); @@ -1412,7 +1412,7 @@ fn test_fee_spike_violation_fails_htlc() { // Assemble the set of keys we can use for signatures for our commitment_signed message. let commit_tx_keys = chan_utils::TxCreationKeys::derive_new(&secp_ctx, &remote_point, &remote_delayed_payment_basepoint, - &remote_htlc_basepoint, &local_revocation_basepoint, &local_htlc_basepoint).unwrap(); + &remote_htlc_basepoint, &local_revocation_basepoint, &local_htlc_basepoint); // Build the remote commitment transaction so we can sign it, and then later use the // signature for the commitment_signed message.