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Fix potential cases where max_dust_htlc_exposure_msat overflows #2722

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Merged
merged 1 commit into from
Nov 12, 2023
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Fix potential cases where max_dust_htlc_exposure_msat overflows #2722

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9 changes: 5 additions & 4 deletions lightning/src/ln/channel.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,7 @@ use crate::util::scid_utils::scid_from_parts;
use crate::io;
use crate::prelude::*;
use core::{cmp,mem,fmt};
use core::convert::TryInto;
use core::ops::Deref;
#[cfg(any(test, fuzzing, debug_assertions))]
use crate::sync::Mutex;
Expand Down Expand Up @@ -1168,8 +1169,8 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
match self.config.options.max_dust_htlc_exposure {
MaxDustHTLCExposure::FeeRateMultiplier(multiplier) => {
let feerate_per_kw = fee_estimator.bounded_sat_per_1000_weight(
ConfirmationTarget::OnChainSweep);
feerate_per_kw as u64 * multiplier
ConfirmationTarget::OnChainSweep) as u64;
feerate_per_kw.saturating_mul(multiplier)
},
MaxDustHTLCExposure::FixedLimitMsat(limit) => limit,
}
Expand Down Expand Up @@ -1753,14 +1754,14 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
context.holder_dust_limit_satoshis + dust_buffer_feerate * htlc_timeout_tx_weight(context.get_channel_type()) / 1000)
};
let on_counterparty_dust_htlc_exposure_msat = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat;
if on_counterparty_dust_htlc_exposure_msat as i64 + htlc_success_dust_limit as i64 * 1000 - 1 > max_dust_htlc_exposure_msat as i64 {
if on_counterparty_dust_htlc_exposure_msat as i64 + htlc_success_dust_limit as i64 * 1000 - 1 > max_dust_htlc_exposure_msat.try_into().unwrap_or(i64::max_value()) {
remaining_msat_below_dust_exposure_limit =
Some(max_dust_htlc_exposure_msat.saturating_sub(on_counterparty_dust_htlc_exposure_msat));
dust_exposure_dust_limit_msat = cmp::max(dust_exposure_dust_limit_msat, htlc_success_dust_limit * 1000);
}

let on_holder_dust_htlc_exposure_msat = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat;
if on_holder_dust_htlc_exposure_msat as i64 + htlc_timeout_dust_limit as i64 * 1000 - 1 > max_dust_htlc_exposure_msat as i64 {
if on_holder_dust_htlc_exposure_msat as i64 + htlc_timeout_dust_limit as i64 * 1000 - 1 > max_dust_htlc_exposure_msat.try_into().unwrap_or(i64::max_value()) {
remaining_msat_below_dust_exposure_limit = Some(cmp::min(
remaining_msat_below_dust_exposure_limit.unwrap_or(u64::max_value()),
max_dust_htlc_exposure_msat.saturating_sub(on_holder_dust_htlc_exposure_msat)));
Expand Down