feat(ethereum-lc): implement misbehaviour check on header

Signed-off-by: aeryz <abdullaheryz@protonmail.com>
unionlabs · Sep 8, 2023 · b8d65dc · b8d65dc
1 parent a175834
commit b8d65dc
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Showing 3 changed files with 34 additions and 10 deletions.
diff --git a/lib/ics-008-wasm-client/src/ibc_client.rs b/lib/ics-008-wasm-client/src/ibc_client.rs
@@ -1,4 +1,4 @@
-use core::fmt::Debug;
+use core::fmt::{Debug, Display};
 
 use cosmwasm_std::{Binary, Deps, DepsMut, Env, MessageInfo};
 use unionlabs::{
@@ -22,7 +22,7 @@ pub enum StorageState {
 pub trait IbcClient {
     type Error: From<TryFromProtoBytesError<TryFromProtoErrorOf<Self::Header>>>
         + From<Error>
-        + ToString;
+        + Display;
     type CustomQuery: cosmwasm_std::CustomQuery;
     // TODO(aeryz): see #583
     type Header: TryFromProto;

diff --git a/light-clients/ethereum-light-client/src/client.rs b/light-clients/ethereum-light-client/src/client.rs
@@ -284,14 +284,8 @@ impl IbcClient for EthereumLightClient {
         deps: Deps<Self::CustomQuery>,
         header: Self::Header,
     ) -> Result<ContractResult, Self::Error> {
-        let height = Height::new(
-            0,
-            header
-                .consensus_update
-                .attested_header
-                .execution
-                .block_number,
-        );
+        let height = Height::new(0, header.consensus_update.attested_header.beacon.slot);
+
         if let Some(consensus_state) =
             read_consensus_state::<CustomQuery, ConsensusState>(deps, &height)?
         {
@@ -308,6 +302,28 @@ impl IbcClient for EthereumLightClient {
             if consensus_state.data.storage_root != storage_root {
                 return Err(Error::StorageRootMismatch);
             }
+
+            if consensus_state.data.slot != header.consensus_update.attested_header.beacon.slot {
+                return Err(Error::SlotCannotBeModified);
+            }
+
+            // Next sync committee for a consensus height can be set if it is not being set
+            // previously, but it cannot be changed or unset after being set.
+            match (
+                consensus_state.data.next_sync_committee,
+                header.consensus_update.next_sync_committee,
+            ) {
+                (Some(_), None) => return Err(Error::NextSyncCommitteeCannotBeModified),
+                (Some(lhs), Some(rhs)) => {
+                    if lhs != rhs.aggregate_pubkey {
+                        return Err(Error::NextSyncCommitteeCannotBeModified);
+                    }
+                }
+                _ => {}
+            }
+
+            // NOTE(aeryz): we don't check the timestamp here since it is calculated based on the
+            // client state and the slot number during update.
         }
 
         // TODO(#605): Do we need to check whether this header's timestamp is between
@@ -718,6 +734,8 @@ mod test {
         ];
 
         for update in updates {
+            EthereumLightClient::check_for_misbehaviour_on_header(deps.as_ref(), update.clone())
+                .unwrap();
             EthereumLightClient::verify_header(deps.as_ref(), mock_env(), update.clone()).unwrap();
             EthereumLightClient::update_state(deps.as_mut(), mock_env(), update.clone()).unwrap();
             // Consensus state is saved to the updated height.

diff --git a/light-clients/ethereum-light-client/src/errors.rs b/light-clients/ethereum-light-client/src/errors.rs
@@ -98,6 +98,12 @@ pub enum Error {
 
     #[error("Wasm client error: {0}")]
     Wasm(String),
+
+    #[error("Next sync committee can't be changed after being set.")]
+    NextSyncCommitteeCannotBeModified,
+
+    #[error("The slot number that is saved previously to the consensus state cannot be changed.")]
+    SlotCannotBeModified,
 }
 
 impl Error {