From 3cc7666c5ae1e3ac2e73870acf67eadac2a532be Mon Sep 17 00:00:00 2001 From: Antoine Riard Date: Thu, 14 Mar 2019 20:57:23 -0400 Subject: [PATCH] Extract preimage from revoked HTLC-Success to claim backward Tweaks by Matt Corallo --- src/ln/channelmonitor.rs | 33 ++++++++++++++++++++++++++++++--- 1 file changed, 30 insertions(+), 3 deletions(-) diff --git a/src/ln/channelmonitor.rs b/src/ln/channelmonitor.rs index 8900b5078..ac03b7bb8 100644 --- a/src/ln/channelmonitor.rs +++ b/src/ln/channelmonitor.rs @@ -1873,8 +1873,9 @@ impl ChannelMonitor { macro_rules! log_claim { ($tx_info: expr, $local_tx: expr, $htlc: expr, $source_avail: expr) => { // We found the output in question, but aren't failing it backwards - // as we have no corresponding source. This implies either it is an - // inbound HTLC or an outbound HTLC on a revoked transaction. + // as we have no corresponding source and no valid remote commitment txid + // to try a weak source binding with same-hash, same-value still-valid offered HTLC. + // This implies either it is an inbound HTLC or an outbound HTLC on a revoked transaction. let outbound_htlc = $local_tx == $htlc.offered; if ($local_tx && revocation_sig_claim) || (outbound_htlc && !$source_avail && (accepted_preimage_claim || offered_preimage_claim)) { @@ -1891,6 +1892,22 @@ impl ChannelMonitor { } } + macro_rules! check_htlc_valid_remote { + ($remote_txid: expr, $htlc_output: expr) => { + if let &Some(txid) = $remote_txid { + for &(ref pending_htlc, ref pending_source) in self.remote_claimable_outpoints.get(&txid).unwrap() { + if pending_htlc.payment_hash == $htlc_output.payment_hash && pending_htlc.amount_msat == $htlc_output.amount_msat { + if let &Some(ref source) = pending_source { + log_claim!("revoked remote commitment tx", false, pending_htlc, true); + payment_data = Some(((**source).clone(), $htlc_output.payment_hash)); + break; + } + } + } + } + } + } + macro_rules! scan_commitment { ($htlcs: expr, $tx_info: expr, $local_tx: expr) => { for (ref htlc_output, source_option) in $htlcs { @@ -1903,7 +1920,17 @@ impl ChannelMonitor { // has timed out, or we screwed up. In any case, we should now // resolve the source HTLC with the original sender. payment_data = Some(((*source).clone(), htlc_output.payment_hash)); - } else { + } else if !$local_tx { + if let Storage::Local { ref current_remote_commitment_txid, .. } = self.key_storage { + check_htlc_valid_remote!(current_remote_commitment_txid, htlc_output); + } + if payment_data.is_none() { + if let Storage::Local { ref prev_remote_commitment_txid, .. } = self.key_storage { + check_htlc_valid_remote!(prev_remote_commitment_txid, htlc_output); + } + } + } + if payment_data.is_none() { log_claim!($tx_info, $local_tx, htlc_output, false); continue 'outer_loop; } -- 2.39.5