From e67d8c6314c4fce465e41652b539f83d0a8c4887 Mon Sep 17 00:00:00 2001 From: Matt Corallo Date: Sun, 18 Nov 2018 16:15:08 -0500 Subject: [PATCH] Don't unwrap() get_channel_update result in HTLC router This fixes a bug in 78232f2aeded08b32fa4ebfeb0b77d80b337518d found by fuzzer - if the channel isn't yet fully established we will call get_channel_update(), get an Err result, and then unwrap() it. If this actually happens it means someone on the network is making up short_channel_ids and trying to route over them, but that shouldn't result in us crashing --- src/ln/channelmanager.rs | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/src/ln/channelmanager.rs b/src/ln/channelmanager.rs index dab22d286..c3d39d8f8 100644 --- a/src/ln/channelmanager.rs +++ b/src/ln/channelmanager.rs @@ -1942,10 +1942,20 @@ impl ChannelManager { // but if we've sent a shutdown and they haven't acknowledged it yet, we just // want to reject the new HTLC and fail it backwards instead of forwarding. if let PendingHTLCStatus::Forward(PendingForwardHTLCInfo { incoming_shared_secret, .. }) = pending_forward_info { + let chan_update = self.get_channel_update(chan); pending_forward_info = PendingHTLCStatus::Fail(HTLCFailureMsg::Relay(msgs::UpdateFailHTLC { channel_id: msg.channel_id, htlc_id: msg.htlc_id, - reason: ChannelManager::build_first_hop_failure_packet(&incoming_shared_secret, 0x1000|20, &self.get_channel_update(chan).unwrap().encode_with_len()[..]), + reason: if let Ok(update) = chan_update { + ChannelManager::build_first_hop_failure_packet(&incoming_shared_secret, 0x1000|20, &update.encode_with_len()[..]) + } else { + // This can only happen if the channel isn't in the fully-funded + // state yet, implying our counterparty is trying to route payments + // over the channel back to themselves (cause no one else should + // know the short_id is a lightning channel yet). We should have no + // problem just calling this unknown_next_peer + ChannelManager::build_first_hop_failure_packet(&incoming_shared_secret, 0x4000|10, &[]) + }, })); } } -- 2.39.5