Do additional pre-flight checks before claiming a payment

[rust-lightning] / lightning / src / ln / channelmanager.rs

diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index 03e07671360880304d7d76952e3373d5c4167144..f92787a0a48b11ef1d405e4dfe7395eaf9bfa0c9 100644 (file)
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -3825,14 +3825,42 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                        // provide the preimage, so worrying too much about the optimal handling isn't worth
                        // it.
                        let mut claimable_amt_msat = 0;
+                       let mut expected_amt_msat = None;
                        let mut valid_mpp = true;
                        for htlc in sources.iter() {
                                if let None = channel_state.as_ref().unwrap().short_to_id.get(&htlc.prev_hop.short_channel_id) {
                                        valid_mpp = false;
                                        break;
                                }
+                               if expected_amt_msat.is_some() && expected_amt_msat != Some(htlc.total_msat) {
+                                       log_error!(self.logger, "Somehow ended up with an MPP payment with different total amounts - this should not be reachable!");
+                                       debug_assert!(false);
+                                       valid_mpp = false;
+                                       break;
+                               }
+                               expected_amt_msat = Some(htlc.total_msat);
+                               if let OnionPayload::Spontaneous(_) = &htlc.onion_payload {
+                                       // We don't currently support MPP for spontaneous payments, so just check
+                                       // that there's one payment here and move on.
+                                       if sources.len() != 1 {
+                                               log_error!(self.logger, "Somehow ended up with an MPP spontaneous payment - this should not be reachable!");
+                                               debug_assert!(false);
+                                               valid_mpp = false;
+                                               break;
+                                       }
+                               }
+
                                claimable_amt_msat += htlc.value;
                        }
+                       if sources.is_empty() || expected_amt_msat.is_none() {
+                               log_info!(self.logger, "Attempted to claim an incomplete payment which no longer had any available HTLCs!");
+                               return;
+                       }
+                       if claimable_amt_msat != expected_amt_msat.unwrap() {
+                               log_info!(self.logger, "Attempted to claim an incomplete payment, expected {} msat, had {} available to claim.",
+                                       expected_amt_msat.unwrap(), claimable_amt_msat);
+                               return;
+                       }
 
                        let mut errs = Vec::new();
                        let mut claimed_any_htlcs = false;