Fix duplicate payment_hashes one immediately failed, one fail crash

Found by fuzzer

diff --git a/src/ln/channel.rs b/src/ln/channel.rs
index 7d858555f8728d5a54d0deb232c05393fde7abdd..47c05de2ab989ab69c00a8f219efb63adebb527a 100644 (file)
--- a/src/ln/channel.rs
+++ b/src/ln/channel.rs
@@ -1131,17 +1131,24 @@ impl Channel {
                                if htlc_id != 0 {
                                        panic!("Duplicate HTLC payment_hash, you probably re-used payment preimages, NEVER DO THIS!");
                                }
-                               htlc_id = htlc.htlc_id;
-                               htlc_amount_msat += htlc.amount_msat;
                                if htlc.state == HTLCState::Committed {
                                        htlc.state = HTLCState::LocalRemoved;
                                } else if htlc.state == HTLCState::RemoteAnnounced {
-                                       panic!("Somehow forwarded HTLC prior to remote revocation!");
+                                       if let Some(PendingHTLCStatus::Forward(_)) = htlc.pending_forward_state {
+                                               panic!("Somehow forwarded HTLC prior to remote revocation!");
+                                       } else {
+                                               // We have to pretend this isn't here - we're probably a duplicate with the
+                                               // same payment_hash as some other HTLC, and the other is getting failed,
+                                               // we'll fail this one as soon as remote commits to it.
+                                               continue;
+                                       }
                                } else if htlc.state == HTLCState::LocalRemoved || htlc.state == HTLCState::LocalRemovedAwaitingCommitment {
                                        return Err(HandleError{err: "Unable to find a pending HTLC which matched the given payment preimage", action: None});
                                } else {
                                        panic!("Have an inbound HTLC when not awaiting remote revoke that had a garbage state");
                                }
+                               htlc_id = htlc.htlc_id;
+                               htlc_amount_msat += htlc.amount_msat;
                        }
                }
                if htlc_amount_msat == 0 {