Return a malformed HTLC message when ephemeral pubkey is garbage

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

diff --git a/src/ln/msgs.rs b/src/ln/msgs.rs
index 6c7c8cfc7281682af919360df1c892342277e820..4067e84b98c18bff1d186b885a5dffbdbbdc06f8 100644 (file)
--- a/src/ln/msgs.rs
+++ b/src/ln/msgs.rs
@@ -1,5 +1,6 @@
 use secp256k1::key::PublicKey;
 use secp256k1::{Secp256k1, Signature};
+use secp256k1;
 use bitcoin::util::hash::Sha256dHash;
 use bitcoin::network::serialize::{deserialize,serialize};
 use bitcoin::blockdata::script::Script;
@@ -476,7 +477,10 @@ unsafe impl internal_traits::NoDealloc for OnionHopData{}
 #[derive(Clone)]
 pub struct OnionPacket {
        pub version: u8,
-       pub public_key: PublicKey,
+       /// In order to ensure we always return an error on Onion decode in compliance with BOLT 4, we
+       /// have to deserialize OnionPackets contained in UpdateAddHTLCs even if the ephemeral public
+       /// key (here) is bogus, so we hold a Result instead of a PublicKey as we'd like.
+       pub public_key: Result<PublicKey, secp256k1::Error>,
        pub hop_data: [u8; 20*65],
        pub hmac: [u8; 32],
 }
@@ -1538,7 +1542,7 @@ impl MsgDecodable for OnionPacket {
                let secp_ctx = Secp256k1::without_caps();
                Ok(Self {
                        version: v[0],
-                       public_key: secp_pubkey!(&secp_ctx, &v[1..34]),
+                       public_key: PublicKey::from_slice(&secp_ctx, &v[1..34]),
                        hop_data,
                        hmac,
                })
@@ -1548,7 +1552,10 @@ impl MsgEncodable for OnionPacket {
        fn encode(&self) -> Vec<u8> {
                let mut res = Vec::with_capacity(1 + 33 + 20*65 + 32);
                res.push(self.version);
-               res.extend_from_slice(&self.public_key.serialize());
+               match self.public_key {
+                       Ok(pubkey) => res.extend_from_slice(&pubkey.serialize()),
+                       Err(_) => res.extend_from_slice(&[0; 33]),
+               }
                res.extend_from_slice(&self.hop_data);
                res.extend_from_slice(&self.hmac);
                res