initial commit

packages/beacon-node/src/chain/lightClient/index.ts

@@ -388,12 +388,13 @@ export class LightClientServer {
     parentBlockSlot: Slot
   ): Promise<void> {
     const blockSlot = block.slot;
-    const header = blockToLightClientHeader(this.config.getForkName(blockSlot), block);
+    const fork = this.config.getForkName(blockSlot);
+    const header = blockToLightClientHeader(fork, block);
 
     const blockRoot = ssz.phase0.BeaconBlockHeader.hashTreeRoot(header.beacon);
     const blockRootHex = toRootHex(blockRoot);
 
-    const syncCommitteeWitness = getSyncCommitteesWitness(postState);
+    const syncCommitteeWitness = getSyncCommitteesWitness(fork, postState);
 
     // Only store current sync committee once per run
     if (!this.storedCurrentSyncCommittee) {

packages/beacon-node/src/chain/lightClient/proofs.ts

@@ -5,28 +5,54 @@ import {
   BLOCK_BODY_EXECUTION_PAYLOAD_GINDEX,
   ForkExecution,
   FINALIZED_ROOT_GINDEX_ELECTRA,
+  ForkName,
+  isForkPostElectra,
 } from "@lodestar/params";
 import {BeaconBlockBody, SSZTypesFor, ssz} from "@lodestar/types";
 
 import {SyncCommitteeWitness} from "./types.js";
 
-export function getSyncCommitteesWitness(state: BeaconStateAllForks): SyncCommitteeWitness {
+export function getSyncCommitteesWitness(fork: ForkName, state: BeaconStateAllForks): SyncCommitteeWitness {
   state.commit();
   const n1 = state.node;
-  const n3 = n1.right; // [1]0110
-  const n6 = n3.left; // 1[0]110
-  const n13 = n6.right; // 10[1]10
-  const n27 = n13.right; // 101[1]0
-  const currentSyncCommitteeRoot = n27.left.root; // n54 1011[0]
-  const nextSyncCommitteeRoot = n27.right.root; // n55 1011[1]
+  let witness: Uint8Array[];
+  let currentSyncCommitteeRoot: Uint8Array;
+  let nextSyncCommitteeRoot: Uint8Array;
 
-  // Witness branch is sorted by descending gindex
-  const witness = [
-    n13.left.root, // 26
-    n6.left.root, // 12
-    n3.right.root, // 7
-    n1.left.root, // 2
-  ];
+  if (isForkPostElectra(fork)) {
+    const n2 = n1.left;
+    const n5 = n2.right;
+    const n10 = n5.left;
+    const n21 = n10.right;
+    const n43 = n21.right;
+
+    currentSyncCommitteeRoot = n43.left.root; // n86
+    nextSyncCommitteeRoot = n43.right.root; // n87
+
+    // Witness branch is sorted by descending gindex
+    witness = [
+      n21.left.root, // 42
+      n10.left.root, // 20
+      n5.right.root, // 11
+      n2.right.root, // 4
+      n1.right.root, // 3
+    ];
+  } else {
+    const n3 = n1.right; // [1]0110
+    const n6 = n3.left; // 1[0]110
+    const n13 = n6.right; // 10[1]10
+    const n27 = n13.right; // 101[1]0
+    currentSyncCommitteeRoot = n27.left.root; // n54 1011[0]
+    nextSyncCommitteeRoot = n27.right.root; // n55 1011[1]
+
+    // Witness branch is sorted by descending gindex
+    witness = [
+      n13.left.root, // 26
+      n6.left.root, // 12
+      n3.right.root, // 7
+      n1.left.root, // 2
+    ];
+  }
 
   return {
     witness,

packages/beacon-node/test/unit/chain/lightclient/proof.test.ts

@@ -1,6 +1,6 @@
 import {describe, it, expect, beforeAll} from "vitest";
 import {BeaconStateAltair} from "@lodestar/state-transition";
-import {SYNC_COMMITTEE_SIZE} from "@lodestar/params";
+import {ForkName, SYNC_COMMITTEE_SIZE} from "@lodestar/params";
 import {altair, ssz} from "@lodestar/types";
 import {verifyMerkleBranch, hash} from "@lodestar/utils";
 import {getNextSyncCommitteeBranch, getSyncCommitteesWitness} from "../../../../src/chain/lightClient/proofs.js";
@@ -25,7 +25,7 @@ describe("chain / lightclient / proof", () => {
   });
 
   it("SyncCommittees proof", () => {
-    const syncCommitteesWitness = getSyncCommitteesWitness(state);
+    const syncCommitteesWitness = getSyncCommitteesWitness(ForkName.altair, state);
     const syncCommitteesLeaf = hash(
       syncCommitteesWitness.currentSyncCommitteeRoot,
       syncCommitteesWitness.nextSyncCommitteeRoot
@@ -42,7 +42,7 @@ describe("chain / lightclient / proof", () => {
   });
 
   it("currentSyncCommittee proof", () => {
-    const syncCommitteesWitness = getSyncCommitteesWitness(state);
+    const syncCommitteesWitness = getSyncCommitteesWitness(ForkName.altair, state);
     const currentSyncCommitteeBranch = [syncCommitteesWitness.nextSyncCommitteeRoot, ...syncCommitteesWitness.witness];
 
     expect(
@@ -56,7 +56,7 @@ describe("chain / lightclient / proof", () => {
   });
 
   it("nextSyncCommittee proof", () => {
-    const syncCommitteesWitness = getSyncCommitteesWitness(state);
+    const syncCommitteesWitness = getSyncCommitteesWitness(ForkName.altair, state);
     const nextSyncCommitteeBranch = getNextSyncCommitteeBranch(syncCommitteesWitness);
 
     expect(

packages/light-client/src/spec/index.ts

@@ -10,7 +10,7 @@ import {
 import {computeSyncPeriodAtSlot} from "../utils/index.js";
 import {getSyncCommitteeAtPeriod, processLightClientUpdate, ProcessUpdateOpts} from "./processLightClientUpdate.js";
 import {ILightClientStore, LightClientStore, LightClientStoreEvents} from "./store.js";
-import {ZERO_FINALITY_BRANCH, ZERO_HEADER, ZERO_SYNC_COMMITTEE, getZeroSyncCommitteeBranch} from "./utils.js";
+import {ZERO_HEADER, ZERO_SYNC_COMMITTEE, getZeroFinalityBranch, getZeroSyncCommitteeBranch} from "./utils.js";
 
 export {isBetterUpdate, toLightClientUpdateSummary} from "./isBetterUpdate.js";
 export type {LightClientUpdateSummary} from "./isBetterUpdate.js";
@@ -39,7 +39,7 @@ export class LightclientSpec {
       nextSyncCommittee: ZERO_SYNC_COMMITTEE,
       nextSyncCommitteeBranch: getZeroSyncCommitteeBranch(this.config.getForkName(finalityUpdate.signatureSlot)),
       finalizedHeader: finalityUpdate.finalizedHeader,
-      finalityBranch: finalityUpdate.finalityBranch,
+      finalityBranch: getZeroFinalityBranch(this.config.getForkName(finalityUpdate.signatureSlot)),
       syncAggregate: finalityUpdate.syncAggregate,
       signatureSlot: finalityUpdate.signatureSlot,
     });
@@ -51,7 +51,7 @@ export class LightclientSpec {
       nextSyncCommittee: ZERO_SYNC_COMMITTEE,
       nextSyncCommitteeBranch: getZeroSyncCommitteeBranch(this.config.getForkName(optimisticUpdate.signatureSlot)),
       finalizedHeader: {beacon: ZERO_HEADER},
-      finalityBranch: ZERO_FINALITY_BRANCH,
+      finalityBranch: getZeroFinalityBranch(this.config.getForkName(optimisticUpdate.signatureSlot)),
       syncAggregate: optimisticUpdate.syncAggregate,
       signatureSlot: optimisticUpdate.signatureSlot,
     });

packages/light-client/src/spec/utils.ts

@@ -33,7 +33,6 @@ export const ZERO_HASH = new Uint8Array(32);
 export const ZERO_PUBKEY = new Uint8Array(48);
 export const ZERO_SYNC_COMMITTEE = ssz.altair.SyncCommittee.defaultValue();
 export const ZERO_HEADER = ssz.phase0.BeaconBlockHeader.defaultValue();
-export const ZERO_FINALITY_BRANCH = Array.from({length: FINALIZED_ROOT_DEPTH}, () => ZERO_HASH);
 /** From https://notes.ethereum.org/@vbuterin/extended_light_client_protocol#Optimistic-head-determining-function */
 const SAFETY_THRESHOLD_FACTOR = 2;
 
@@ -53,6 +52,12 @@ export function getZeroSyncCommitteeBranch(fork: ForkName): Uint8Array[] {
   return Array.from({length: nextSyncCommitteeDepth}, () => ZERO_HASH);
 }
 
+export function getZeroFinalityBranch(fork: ForkName): Uint8Array[] {
+  const finalizedRootDepth = isForkPostElectra(fork) ? FINALIZED_ROOT_DEPTH_ELECTRA : FINALIZED_ROOT_DEPTH;
+
+  return Array.from({length: finalizedRootDepth}, () => ZERO_HASH);
+}
+
 export function isSyncCommitteeUpdate(update: LightClientUpdate): boolean {
   return (
     // Fast return for when constructing full LightClientUpdate from partial updates
@@ -65,7 +70,8 @@ export function isSyncCommitteeUpdate(update: LightClientUpdate): boolean {
 export function isFinalityUpdate(update: LightClientUpdate): boolean {
   return (
     // Fast return for when constructing full LightClientUpdate from partial updates
-    update.finalityBranch !== ZERO_FINALITY_BRANCH &&
+    update.finalityBranch !==
+      getZeroFinalityBranch(isElectraLightClientUpdate(update) ? ForkName.electra : ForkName.altair) &&
     update.finalityBranch.some((branch) => !byteArrayEquals(branch, ZERO_HASH))
   );
 }

packages/light-client/src/validation.ts

@@ -2,6 +2,7 @@ import bls from "@chainsafe/bls";
 import type {PublicKey, Signature} from "@chainsafe/bls/types";
 import {
   altair,
+  isELectraLightClientFinalityUpdate,
   isElectraLightClientUpdate,
   LightClientFinalityUpdate,
   LightClientUpdate,
@@ -19,6 +20,7 @@ import {
   NEXT_SYNC_COMMITTEE_DEPTH_ELECTRA,
   FINALIZED_ROOT_DEPTH_ELECTRA,
   NEXT_SYNC_COMMITTEE_INDEX_ELECTRA,
+  FINALIZED_ROOT_INDEX_ELECTRA,
 } from "@lodestar/params";
 import {BeaconConfig} from "@lodestar/config";
 import {isValidMerkleBranch} from "./utils/verifyMerkleBranch.js";
@@ -80,12 +82,19 @@ export function assertValidLightClientUpdate(
  * Where `hashTreeRoot(state) == update.finalityHeader.stateRoot`
  */
 export function assertValidFinalityProof(update: LightClientFinalityUpdate): void {
+  const finalizedRootDepth = isELectraLightClientFinalityUpdate(update)
+    ? FINALIZED_ROOT_DEPTH_ELECTRA
+    : FINALIZED_ROOT_DEPTH;
+  const finalizedRootIndex = isELectraLightClientFinalityUpdate(update)
+    ? FINALIZED_ROOT_INDEX_ELECTRA
+    : FINALIZED_ROOT_INDEX;
+
   if (
     !isValidMerkleBranch(
       ssz.phase0.BeaconBlockHeader.hashTreeRoot(update.finalizedHeader.beacon),
       update.finalityBranch,
-      FINALIZED_ROOT_DEPTH,
-      FINALIZED_ROOT_INDEX,
+      finalizedRootDepth,
+      finalizedRootIndex,
       update.attestedHeader.beacon.stateRoot
     )
   ) {

packages/types/src/utils/typeguards.ts

@@ -15,6 +15,7 @@ import {
   BeaconBlock,
   Attestation,
   LightClientUpdate,
+  LightClientFinalityUpdate,
 } from "../types.js";
 
 export function isExecutionPayload<F extends ForkExecution>(
@@ -80,3 +81,13 @@ export function isElectraLightClientUpdate(update: LightClientUpdate): update is
     updatePostElectra.finalityBranch.length === FINALIZED_ROOT_DEPTH_ELECTRA
   );
 }
+
+export function isELectraLightClientFinalityUpdate(
+  update: LightClientFinalityUpdate
+): update is LightClientFinalityUpdate<ForkPostElectra> {
+  const updatePostElectra = update as LightClientUpdate<ForkPostElectra>;
+  return (
+    updatePostElectra.finalityBranch !== undefined &&
+    updatePostElectra.finalityBranch.length === FINALIZED_ROOT_DEPTH_ELECTRA
+  );
+}