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TheBlueMatt opened this issue Apr 5, 2023 · 0 comments · Fixed by #3450
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ChannelMonitor balances don't reflect preimages for other channels #2153

TheBlueMatt opened this issue Apr 5, 2023 · 0 comments · Fixed by #3450
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0.1

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@TheBlueMatt
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If a ChannelMonitor has a preimage in it that we need to claim an HTLC on a different channel, that ChannelMonior's balance set may still be empty, despite the fact that we absolutely cannot archive/remove it.
@TheBlueMatt TheBlueMatt added this to the 0.1 milestone Apr 5, 2023
TheBlueMatt added a commit to TheBlueMatt/rust-lightning that referenced this issue Dec 8, 2024
@TheBlueMatt
Ensure monitors are not archived if they have a preimage we need
eb56ad1 
When a `ChannelMonitor` sees a payment preimage on chain for an
outbound HTLC, it creates a `MonitorEvent` containing the preimage
to pass to the inbound edge. The inclusion of the transaction
containing the payment preimage (plus six confirmations) also
results in the corresponding `Balance` being removed from the live
balance set, allowing the `ChannelMonitor` to be pruned (after a
further 4032 blocks).

While `MonitorEvent`s should always be processed in a timely
manner, if a node is suffering from a bug  where they are not, its
possible for 4038 blocks to pass with the preimage-containing
`MonitorEvent` still pending. If that happens, its possible the
`ChannelMonitor` is archived even though the preimage in it is
needed in another channel (or `ChannelMonitor`), causing funds
loss.

Luckily the fix is simple - check for pending events before
allowing a `ChannelMonitor` to be archived.

Fixes lightningdevkit#2153
@TheBlueMatt TheBlueMatt mentioned this issue Dec 8, 2024
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@TheBlueMatt TheBlueMatt mentioned this issue Dec 12, 2024
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Ensure monitors are not archived if they have a preimage we need TheBlueMatt/rust-lightning
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@TheBlueMatt