X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;ds=sidebyside;f=src%2Fln%2Fchannelmonitor.rs;h=8c3fcc3f0a02ad21dbb838759241e57eec4e70b7;hb=4f644f225c059e2731d848077adac11edb9cdcca;hp=0daedeac955482d6f1b4936f68ce3538ca8599ca;hpb=a48fd6ddfa2a21c449657185824f32a1eb386b58;p=rust-lightning diff --git a/src/ln/channelmonitor.rs b/src/ln/channelmonitor.rs index 0daedeac..8c3fcc3f 100644 --- a/src/ln/channelmonitor.rs +++ b/src/ln/channelmonitor.rs @@ -1,6 +1,7 @@ use bitcoin::blockdata::block::BlockHeader; use bitcoin::blockdata::transaction::{TxIn,TxOut,SigHashType,Transaction}; use bitcoin::blockdata::script::Script; +use bitcoin::network::serialize; use bitcoin::util::hash::Sha256dHash; use bitcoin::util::bip143; @@ -15,6 +16,7 @@ use ln::chan_utils::HTLCOutputInCommitment; use chain::chaininterface::{ChainListener, ChainWatchInterface, BroadcasterInterface}; use chain::transaction::OutPoint; use util::sha2::Sha256; +use util::byte_utils; use std::collections::HashMap; use std::sync::{Arc,Mutex}; @@ -115,7 +117,7 @@ const CLTV_SHARED_CLAIM_BUFFER: u32 = 12; /// HTLC-Success transaction. const CLTV_CLAIM_BUFFER: u32 = 6; -#[derive(Clone)] +#[derive(Clone, PartialEq)] enum KeyStorage { PrivMode { revocation_base_key: SecretKey, @@ -128,8 +130,9 @@ enum KeyStorage { } } -#[derive(Clone)] +#[derive(Clone, PartialEq)] struct LocalSignedTx { + /// txid of the transaction in tx, just used to make comparison faster txid: Sha256dHash, tx: Transaction, revocation_key: PublicKey, @@ -140,6 +143,9 @@ struct LocalSignedTx { htlc_outputs: Vec<(HTLCOutputInCommitment, Signature, Signature)>, } +const SERIALIZATION_VERSION: u8 = 1; +const MIN_SERIALIZATION_VERSION: u8 = 1; + pub struct ChannelMonitor { funding_txo: Option, commitment_transaction_number_obscure_factor: u64, @@ -155,9 +161,16 @@ pub struct ChannelMonitor { old_secrets: [([u8; 32], u64); 49], remote_claimable_outpoints: HashMap>, - remote_htlc_outputs_on_chain: Mutex>, - //hash to commitment number mapping use to determine the state of transaction owning it - // (revoked/non-revoked) and so lightnen pruning + /// We cannot identify HTLC-Success or HTLC-Timeout transactions by themselves on the chain. + /// Nor can we figure out their commitment numbers without the commitment transaction they are + /// spending. Thus, in order to claim them via revocation key, we track all the remote + /// commitment transactions which we find on-chain, mapping them to the commitment number which + /// can be used to derive the revocation key and claim the transactions. + remote_commitment_txn_on_chain: Mutex>, + /// Cache used to make pruning of payment_preimages faster. + /// Maps payment_hash values to commitment numbers for remote transactions for non-revoked + /// remote transactions (ie should remain pretty small). + /// Serialized to disk but should generally not be sent to Watchtowers. remote_hash_commitment_number: HashMap<[u8; 32], u64>, // We store two local commitment transactions to avoid any race conditions where we may update @@ -188,7 +201,7 @@ impl Clone for ChannelMonitor { old_secrets: self.old_secrets.clone(), remote_claimable_outpoints: self.remote_claimable_outpoints.clone(), - remote_htlc_outputs_on_chain: Mutex::new((*self.remote_htlc_outputs_on_chain.lock().unwrap()).clone()), + remote_commitment_txn_on_chain: Mutex::new((*self.remote_commitment_txn_on_chain.lock().unwrap()).clone()), remote_hash_commitment_number: self.remote_hash_commitment_number.clone(), prev_local_signed_commitment_tx: self.prev_local_signed_commitment_tx.clone(), @@ -202,6 +215,40 @@ impl Clone for ChannelMonitor { } } +#[cfg(any(test, feature = "fuzztarget"))] +/// Used only in testing and fuzztarget to check serialization roundtrips don't change the +/// underlying object +impl PartialEq for ChannelMonitor { + fn eq(&self, other: &Self) -> bool { + if self.funding_txo != other.funding_txo || + self.commitment_transaction_number_obscure_factor != other.commitment_transaction_number_obscure_factor || + self.key_storage != other.key_storage || + self.delayed_payment_base_key != other.delayed_payment_base_key || + self.their_htlc_base_key != other.their_htlc_base_key || + self.their_cur_revocation_points != other.their_cur_revocation_points || + self.our_to_self_delay != other.our_to_self_delay || + self.their_to_self_delay != other.their_to_self_delay || + self.remote_claimable_outpoints != other.remote_claimable_outpoints || + self.remote_hash_commitment_number != other.remote_hash_commitment_number || + self.prev_local_signed_commitment_tx != other.prev_local_signed_commitment_tx || + self.current_local_signed_commitment_tx != other.current_local_signed_commitment_tx || + self.payment_preimages != other.payment_preimages || + self.destination_script != other.destination_script + { + false + } else { + for (&(ref secret, ref idx), &(ref o_secret, ref o_idx)) in self.old_secrets.iter().zip(other.old_secrets.iter()) { + if secret != o_secret || idx != o_idx { + return false + } + } + let us = self.remote_commitment_txn_on_chain.lock().unwrap(); + let them = other.remote_commitment_txn_on_chain.lock().unwrap(); + *us == *them + } + } +} + impl ChannelMonitor { pub fn new(revocation_base_key: &SecretKey, delayed_payment_base_key: &PublicKey, htlc_base_key: &SecretKey, our_to_self_delay: u16, destination_script: Script) -> ChannelMonitor { ChannelMonitor { @@ -221,7 +268,7 @@ impl ChannelMonitor { old_secrets: [([0; 32], 1 << 48); 49], remote_claimable_outpoints: HashMap::new(), - remote_htlc_outputs_on_chain: Mutex::new(HashMap::new()), + remote_commitment_txn_on_chain: Mutex::new(HashMap::new()), remote_hash_commitment_number: HashMap::new(), prev_local_signed_commitment_tx: None, @@ -431,6 +478,392 @@ impl ChannelMonitor { self.funding_txo } + /// Serializes into a vec, with various modes for the exposed pub fns + fn serialize(&self, for_local_storage: bool) -> Vec { + let mut res = Vec::new(); + res.push(SERIALIZATION_VERSION); + res.push(MIN_SERIALIZATION_VERSION); + + match self.funding_txo { + Some(outpoint) => { + res.extend_from_slice(&outpoint.txid[..]); + res.extend_from_slice(&byte_utils::be16_to_array(outpoint.index)); + }, + None => { + // We haven't even been initialized...not sure why anyone is serializing us, but + // not much to give them. + return res; + }, + } + + // Set in initial Channel-object creation, so should always be set by now: + res.extend_from_slice(&byte_utils::be48_to_array(self.commitment_transaction_number_obscure_factor)); + + match self.key_storage { + KeyStorage::PrivMode { ref revocation_base_key, ref htlc_base_key } => { + res.push(0); + res.extend_from_slice(&revocation_base_key[..]); + res.extend_from_slice(&htlc_base_key[..]); + }, + KeyStorage::SigsMode { .. } => unimplemented!(), + } + + res.extend_from_slice(&self.delayed_payment_base_key.serialize()); + res.extend_from_slice(&self.their_htlc_base_key.as_ref().unwrap().serialize()); + + match self.their_cur_revocation_points { + Some((idx, pubkey, second_option)) => { + res.extend_from_slice(&byte_utils::be48_to_array(idx)); + res.extend_from_slice(&pubkey.serialize()); + match second_option { + Some(second_pubkey) => { + res.extend_from_slice(&second_pubkey.serialize()); + }, + None => { + res.extend_from_slice(&[0; 33]); + }, + } + }, + None => { + res.extend_from_slice(&byte_utils::be48_to_array(0)); + }, + } + + res.extend_from_slice(&byte_utils::be16_to_array(self.our_to_self_delay)); + res.extend_from_slice(&byte_utils::be16_to_array(self.their_to_self_delay.unwrap())); + + for &(ref secret, ref idx) in self.old_secrets.iter() { + res.extend_from_slice(secret); + res.extend_from_slice(&byte_utils::be64_to_array(*idx)); + } + + macro_rules! serialize_htlc_in_commitment { + ($htlc_output: expr) => { + res.push($htlc_output.offered as u8); + res.extend_from_slice(&byte_utils::be64_to_array($htlc_output.amount_msat)); + res.extend_from_slice(&byte_utils::be32_to_array($htlc_output.cltv_expiry)); + res.extend_from_slice(&$htlc_output.payment_hash); + res.extend_from_slice(&byte_utils::be32_to_array($htlc_output.transaction_output_index)); + } + } + + res.extend_from_slice(&byte_utils::be64_to_array(self.remote_claimable_outpoints.len() as u64)); + for (txid, htlc_outputs) in self.remote_claimable_outpoints.iter() { + res.extend_from_slice(&txid[..]); + res.extend_from_slice(&byte_utils::be64_to_array(htlc_outputs.len() as u64)); + for htlc_output in htlc_outputs.iter() { + serialize_htlc_in_commitment!(htlc_output); + } + } + + { + let remote_commitment_txn_on_chain = self.remote_commitment_txn_on_chain.lock().unwrap(); + res.extend_from_slice(&byte_utils::be64_to_array(remote_commitment_txn_on_chain.len() as u64)); + for (txid, commitment_number) in remote_commitment_txn_on_chain.iter() { + res.extend_from_slice(&txid[..]); + res.extend_from_slice(&byte_utils::be48_to_array(*commitment_number)); + } + } + + if for_local_storage { + res.extend_from_slice(&byte_utils::be64_to_array(self.remote_hash_commitment_number.len() as u64)); + for (payment_hash, commitment_number) in self.remote_hash_commitment_number.iter() { + res.extend_from_slice(payment_hash); + res.extend_from_slice(&byte_utils::be48_to_array(*commitment_number)); + } + } else { + res.extend_from_slice(&byte_utils::be64_to_array(0)); + } + + macro_rules! serialize_local_tx { + ($local_tx: expr) => { + let tx_ser = serialize::serialize(&$local_tx.tx).unwrap(); + res.extend_from_slice(&byte_utils::be64_to_array(tx_ser.len() as u64)); + res.extend_from_slice(&tx_ser); + + res.extend_from_slice(&$local_tx.revocation_key.serialize()); + res.extend_from_slice(&$local_tx.a_htlc_key.serialize()); + res.extend_from_slice(&$local_tx.b_htlc_key.serialize()); + res.extend_from_slice(&$local_tx.delayed_payment_key.serialize()); + + res.extend_from_slice(&byte_utils::be64_to_array($local_tx.feerate_per_kw)); + res.extend_from_slice(&byte_utils::be64_to_array($local_tx.htlc_outputs.len() as u64)); + for &(ref htlc_output, ref their_sig, ref our_sig) in $local_tx.htlc_outputs.iter() { + serialize_htlc_in_commitment!(htlc_output); + res.extend_from_slice(&their_sig.serialize_compact(&self.secp_ctx)); + res.extend_from_slice(&our_sig.serialize_compact(&self.secp_ctx)); + } + } + } + + if let Some(ref prev_local_tx) = self.prev_local_signed_commitment_tx { + res.push(1); + serialize_local_tx!(prev_local_tx); + } else { + res.push(0); + } + + if let Some(ref cur_local_tx) = self.current_local_signed_commitment_tx { + res.push(1); + serialize_local_tx!(cur_local_tx); + } else { + res.push(0); + } + + res.extend_from_slice(&byte_utils::be64_to_array(self.payment_preimages.len() as u64)); + for payment_preimage in self.payment_preimages.values() { + res.extend_from_slice(payment_preimage); + } + + res.extend_from_slice(&byte_utils::be64_to_array(self.destination_script.len() as u64)); + res.extend_from_slice(&self.destination_script[..]); + + res + } + + /// Encodes this monitor into a byte array, suitable for writing to disk. + pub fn serialize_for_disk(&self) -> Vec { + self.serialize(true) + } + + /// Encodes this monitor into a byte array, suitable for sending to a remote watchtower + pub fn serialize_for_watchtower(&self) -> Vec { + self.serialize(false) + } + + /// Attempts to decode a serialized monitor + pub fn deserialize(data: &[u8]) -> Option { + let mut read_pos = 0; + macro_rules! read_bytes { + ($byte_count: expr) => { + { + if ($byte_count as usize) > data.len() - read_pos { + return None; + } + read_pos += $byte_count as usize; + &data[read_pos - $byte_count as usize..read_pos] + } + } + } + + let secp_ctx = Secp256k1::new(); + macro_rules! unwrap_obj { + ($key: expr) => { + match $key { + Ok(res) => res, + Err(_) => return None, + } + } + } + + let _ver = read_bytes!(1)[0]; + let min_ver = read_bytes!(1)[0]; + if min_ver > SERIALIZATION_VERSION { + return None; + } + + // Technically this can fail and serialize fail a round-trip, but only for serialization of + // barely-init'd ChannelMonitors that we can't do anything with. + let funding_txo = Some(OutPoint { + txid: Sha256dHash::from(read_bytes!(32)), + index: byte_utils::slice_to_be16(read_bytes!(2)), + }); + let commitment_transaction_number_obscure_factor = byte_utils::slice_to_be48(read_bytes!(6)); + + let key_storage = match read_bytes!(1)[0] { + 0 => { + KeyStorage::PrivMode { + revocation_base_key: unwrap_obj!(SecretKey::from_slice(&secp_ctx, read_bytes!(32))), + htlc_base_key: unwrap_obj!(SecretKey::from_slice(&secp_ctx, read_bytes!(32))), + } + }, + _ => return None, + }; + + let delayed_payment_base_key = unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33))); + let their_htlc_base_key = Some(unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33)))); + + let their_cur_revocation_points = { + let first_idx = byte_utils::slice_to_be48(read_bytes!(6)); + if first_idx == 0 { + None + } else { + let first_point = unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33))); + let second_point_slice = read_bytes!(33); + if second_point_slice[0..32] == [0; 32] && second_point_slice[32] == 0 { + Some((first_idx, first_point, None)) + } else { + Some((first_idx, first_point, Some(unwrap_obj!(PublicKey::from_slice(&secp_ctx, second_point_slice))))) + } + } + }; + + let our_to_self_delay = byte_utils::slice_to_be16(read_bytes!(2)); + let their_to_self_delay = Some(byte_utils::slice_to_be16(read_bytes!(2))); + + let mut old_secrets = [([0; 32], 1 << 48); 49]; + for &mut (ref mut secret, ref mut idx) in old_secrets.iter_mut() { + secret.copy_from_slice(read_bytes!(32)); + *idx = byte_utils::slice_to_be64(read_bytes!(8)); + } + + macro_rules! read_htlc_in_commitment { + () => { + { + let offered = match read_bytes!(1)[0] { + 0 => false, 1 => true, + _ => return None, + }; + let amount_msat = byte_utils::slice_to_be64(read_bytes!(8)); + let cltv_expiry = byte_utils::slice_to_be32(read_bytes!(4)); + let mut payment_hash = [0; 32]; + payment_hash[..].copy_from_slice(read_bytes!(32)); + let transaction_output_index = byte_utils::slice_to_be32(read_bytes!(4)); + + HTLCOutputInCommitment { + offered, amount_msat, cltv_expiry, payment_hash, transaction_output_index + } + } + } + } + + let remote_claimable_outpoints_len = byte_utils::slice_to_be64(read_bytes!(8)); + if remote_claimable_outpoints_len > data.len() as u64 / 64 { return None; } + let mut remote_claimable_outpoints = HashMap::with_capacity(remote_claimable_outpoints_len as usize); + for _ in 0..remote_claimable_outpoints_len { + let txid = Sha256dHash::from(read_bytes!(32)); + let outputs_count = byte_utils::slice_to_be64(read_bytes!(8)); + if outputs_count > data.len() as u64 * 32 { return None; } + let mut outputs = Vec::with_capacity(outputs_count as usize); + for _ in 0..outputs_count { + outputs.push(read_htlc_in_commitment!()); + } + if let Some(_) = remote_claimable_outpoints.insert(txid, outputs) { + return None; + } + } + + let remote_commitment_txn_on_chain_len = byte_utils::slice_to_be64(read_bytes!(8)); + if remote_commitment_txn_on_chain_len > data.len() as u64 / 32 { return None; } + let mut remote_commitment_txn_on_chain = HashMap::with_capacity(remote_commitment_txn_on_chain_len as usize); + for _ in 0..remote_commitment_txn_on_chain_len { + let txid = Sha256dHash::from(read_bytes!(32)); + let commitment_number = byte_utils::slice_to_be48(read_bytes!(6)); + if let Some(_) = remote_commitment_txn_on_chain.insert(txid, commitment_number) { + return None; + } + } + + let remote_hash_commitment_number_len = byte_utils::slice_to_be64(read_bytes!(8)); + if remote_hash_commitment_number_len > data.len() as u64 / 32 { return None; } + let mut remote_hash_commitment_number = HashMap::with_capacity(remote_hash_commitment_number_len as usize); + for _ in 0..remote_hash_commitment_number_len { + let mut txid = [0; 32]; + txid[..].copy_from_slice(read_bytes!(32)); + let commitment_number = byte_utils::slice_to_be48(read_bytes!(6)); + if let Some(_) = remote_hash_commitment_number.insert(txid, commitment_number) { + return None; + } + } + + macro_rules! read_local_tx { + () => { + { + let tx_len = byte_utils::slice_to_be64(read_bytes!(8)); + let tx_ser = read_bytes!(tx_len); + let tx: Transaction = unwrap_obj!(serialize::deserialize(tx_ser)); + if serialize::serialize(&tx).unwrap() != tx_ser { + // We check that the tx re-serializes to the same form to ensure there is + // no extra data, and as rust-bitcoin doesn't handle the 0-input ambiguity + // all that well. + return None; + } + + let revocation_key = unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33))); + let a_htlc_key = unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33))); + let b_htlc_key = unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33))); + let delayed_payment_key = unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33))); + let feerate_per_kw = byte_utils::slice_to_be64(read_bytes!(8)); + + let htlc_outputs_len = byte_utils::slice_to_be64(read_bytes!(8)); + if htlc_outputs_len > data.len() as u64 / 128 { return None; } + let mut htlc_outputs = Vec::with_capacity(htlc_outputs_len as usize); + for _ in 0..htlc_outputs_len { + htlc_outputs.push((read_htlc_in_commitment!(), + unwrap_obj!(Signature::from_compact(&secp_ctx, read_bytes!(64))), + unwrap_obj!(Signature::from_compact(&secp_ctx, read_bytes!(64))))); + } + + LocalSignedTx { + txid: tx.txid(), + tx, revocation_key, a_htlc_key, b_htlc_key, delayed_payment_key, feerate_per_kw, htlc_outputs + } + } + } + } + + let prev_local_signed_commitment_tx = match read_bytes!(1)[0] { + 0 => None, + 1 => { + Some(read_local_tx!()) + }, + _ => return None, + }; + + let current_local_signed_commitment_tx = match read_bytes!(1)[0] { + 0 => None, + 1 => { + Some(read_local_tx!()) + }, + _ => return None, + }; + + let payment_preimages_len = byte_utils::slice_to_be64(read_bytes!(8)); + if payment_preimages_len > data.len() as u64 / 32 { return None; } + let mut payment_preimages = HashMap::with_capacity(payment_preimages_len as usize); + let mut sha = Sha256::new(); + for _ in 0..payment_preimages_len { + let mut preimage = [0; 32]; + preimage[..].copy_from_slice(read_bytes!(32)); + sha.reset(); + sha.input(&preimage); + let mut hash = [0; 32]; + sha.result(&mut hash); + if let Some(_) = payment_preimages.insert(hash, preimage) { + return None; + } + } + + let destination_script_len = byte_utils::slice_to_be64(read_bytes!(8)); + let destination_script = Script::from(read_bytes!(destination_script_len).to_vec()); + + Some(ChannelMonitor { + funding_txo, + commitment_transaction_number_obscure_factor, + + key_storage, + delayed_payment_base_key, + their_htlc_base_key, + their_cur_revocation_points, + + our_to_self_delay, + their_to_self_delay, + + old_secrets, + remote_claimable_outpoints, + remote_commitment_txn_on_chain: Mutex::new(remote_commitment_txn_on_chain), + remote_hash_commitment_number, + + prev_local_signed_commitment_tx, + current_local_signed_commitment_tx, + + payment_preimages, + + destination_script, + secp_ctx, + }) + } + //TODO: Functions to serialize/deserialize (with different forms depending on which information //we want to leave out (eg funding_txo, etc). @@ -591,10 +1024,10 @@ impl ChannelMonitor { } } - if !inputs.is_empty() || !txn_to_broadcast.is_empty() { + if !inputs.is_empty() || !txn_to_broadcast.is_empty() { // ie we're confident this is actually ours // We're definitely a remote commitment transaction! // TODO: Register commitment_txid with the ChainWatchInterface! - self.remote_htlc_outputs_on_chain.lock().unwrap().insert(commitment_txid, commitment_number); + self.remote_commitment_txn_on_chain.lock().unwrap().insert(commitment_txid, commitment_number); } if inputs.is_empty() { return txn_to_broadcast; } // Nothing to be done...probably a false positive/local tx @@ -619,6 +1052,15 @@ impl ChannelMonitor { txn_to_broadcast.push(spend_tx); } else if let Some(per_commitment_data) = per_commitment_option { + // While this isn't useful yet, there is a potential race where if a counterparty + // revokes a state at the same time as the commitment transaction for that state is + // confirmed, and the watchtower receives the block before the user, the user could + // upload a new ChannelMonitor with the revocation secret but the watchtower has + // already processed the block, resulting in the remote_commitment_txn_on_chain entry + // not being generated by the above conditional. Thus, to be safe, we go ahead and + // insert it here. + self.remote_commitment_txn_on_chain.lock().unwrap().insert(commitment_txid, commitment_number); + if let Some(revocation_points) = self.their_cur_revocation_points { let revocation_point_option = if revocation_points.0 == commitment_number { Some(&revocation_points.1) } @@ -723,7 +1165,7 @@ impl ChannelMonitor { } } } else { - //TODO: For each input check if its in our remote_htlc_outputs_on_chain map! + //TODO: For each input check if its in our remote_commitment_txn_on_chain map! } txn_to_broadcast