Randomize initial onion packet data.

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

diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index 21eab0c48df447e5a2df0eab7947737043db697c..5a59d0c45af798aa22f0291b88eeb1b242dff52e 100644 (file)
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -896,6 +896,21 @@ impl<'a> ChannelManager<'a> {
                };
 
                let pending_forward_info = if next_hop_data.hmac == [0; 32] {
+                               #[cfg(test)]
+                               {
+                                       // In tests, make sure that the initial onion pcket data is, at least, non-0.
+                                       // We could do some fancy randomness test here, but, ehh, whatever.
+                                       // This checks for the issue where you can calculate the path length given the
+                                       // onion data as all the path entries that the originator sent will be here
+                                       // as-is (and were originally 0s).
+                                       // Of course reverse path calculation is still pretty easy given naive routing
+                                       // algorithms, but this fixes the most-obvious case.
+                                       let mut new_packet_data = [0; 19*65];
+                                       chacha.process(&msg.onion_routing_packet.hop_data[65..], &mut new_packet_data[0..19*65]);
+                                       assert_ne!(new_packet_data[0..65], [0; 65][..]);
+                                       assert_ne!(new_packet_data[..], [0; 19*65][..]);
+                               }
+
                                // OUR PAYMENT!
                                // final_expiry_too_soon
                                if (msg.cltv_expiry as u64) < self.latest_block_height.load(Ordering::Acquire) as u64 + (CLTV_CLAIM_BUFFER + LATENCY_GRACE_PERIOD_BLOCKS) as u64 {
@@ -1089,14 +1104,14 @@ impl<'a> ChannelManager<'a> {
                        }
                }
 
-               let session_priv = self.keys_manager.get_session_key();
+               let (session_priv, prng_seed) = self.keys_manager.get_onion_rand();
 
                let cur_height = self.latest_block_height.load(Ordering::Acquire) as u32 + 1;
 
                let onion_keys = secp_call!(onion_utils::construct_onion_keys(&self.secp_ctx, &route, &session_priv),
                                APIError::RouteError{err: "Pubkey along hop was maliciously selected"});
                let (onion_payloads, htlc_msat, htlc_cltv) = onion_utils::build_onion_payloads(&route, cur_height)?;
-               let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, &payment_hash);
+               let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, prng_seed, &payment_hash);
 
                let _ = self.total_consistency_lock.read().unwrap();