fix: check pubkey or validator index known to a state (#7284)

* fix: check pubkey or validator index known to a state

* chore: add more comments

Author: twoeths

packages/state-transition/src/block/processConsolidationRequest.ts

@@ -3,7 +3,7 @@ import {electra, ssz} from "@lodestar/types";
 
 import {CachedBeaconStateElectra} from "../types.js";
 import {hasEth1WithdrawalCredential} from "../util/capella.js";
-import {hasExecutionWithdrawalCredential, switchToCompoundingValidator} from "../util/electra.js";
+import {hasExecutionWithdrawalCredential, isPubkeyKnown, switchToCompoundingValidator} from "../util/electra.js";
 import {computeConsolidationEpochAndUpdateChurn} from "../util/epoch.js";
 import {getConsolidationChurnLimit, isActiveValidator} from "../util/validator.js";
 
@@ -13,6 +13,10 @@ export function processConsolidationRequest(
   consolidationRequest: electra.ConsolidationRequest
 ): void {
   const {sourcePubkey, targetPubkey, sourceAddress} = consolidationRequest;
+  if (!isPubkeyKnown(state, sourcePubkey) || !isPubkeyKnown(state, targetPubkey)) {
+    return;
+  }
+
   const sourceIndex = state.epochCtx.getValidatorIndex(sourcePubkey);
   const targetIndex = state.epochCtx.getValidatorIndex(targetPubkey);
 
@@ -97,6 +101,7 @@ function isValidSwitchToCompoundRequest(
 
   // Verify pubkey exists
   if (sourceIndex === null) {
+    // this check is mainly to make the compiler happy, pubkey is checked by the consumer already
     return false;
   }
 

packages/state-transition/src/epoch/processPendingDeposits.ts

@@ -3,7 +3,7 @@ import {PendingDeposit} from "@lodestar/types/lib/electra/types.js";
 import {addValidatorToRegistry, isValidDepositSignature} from "../block/processDeposit.js";
 import {CachedBeaconStateElectra, EpochTransitionCache} from "../types.js";
 import {increaseBalance} from "../util/balance.js";
-import {hasCompoundingWithdrawalCredential} from "../util/electra.js";
+import {hasCompoundingWithdrawalCredential, isValidatorKnown} from "../util/electra.js";
 import {computeStartSlotAtEpoch} from "../util/epoch.js";
 import {getActivationExitChurnLimit} from "../util/validator.js";
 
@@ -51,7 +51,7 @@ export function processPendingDeposits(state: CachedBeaconStateElectra, cache: E
     let isValidatorWithdrawn = false;
 
     const validatorIndex = state.epochCtx.getValidatorIndex(deposit.pubkey);
-    if (validatorIndex !== null) {
+    if (isValidatorKnown(state, validatorIndex)) {
       const validator = state.validators.getReadonly(validatorIndex);
       isValidatorExited = validator.exitEpoch < FAR_FUTURE_EPOCH;
       isValidatorWithdrawn = validator.withdrawableEpoch < nextEpoch;
@@ -103,7 +103,7 @@ function applyPendingDeposit(
   const {pubkey, withdrawalCredentials, amount, signature} = deposit;
   const cachedBalances = cache.balances;
 
-  if (validatorIndex === null) {
+  if (!isValidatorKnown(state, validatorIndex)) {
     // Verify the deposit signature (proof of possession) which is not checked by the deposit contract
     if (isValidDepositSignature(state.config, pubkey, withdrawalCredentials, amount, signature)) {
       addValidatorToRegistry(ForkSeq.electra, state, pubkey, withdrawalCredentials, amount);

packages/state-transition/src/util/electra.ts

@@ -45,3 +45,20 @@ export function queueExcessActiveBalance(state: CachedBeaconStateElectra, index:
     state.pendingDeposits.push(pendingDeposit);
   }
 }
+
+/**
+ * Since we share pubkey2index, pubkey maybe added by other epoch transition but we don't have that validator in this state
+ */
+export function isPubkeyKnown(state: CachedBeaconStateElectra, pubkey: Uint8Array): boolean {
+  return isValidatorKnown(state, state.epochCtx.getValidatorIndex(pubkey));
+}
+
+/**
+ * Since we share pubkey2index, validatorIndex maybe not null but we don't have that validator in this state
+ */
+export function isValidatorKnown(
+  state: CachedBeaconStateElectra,
+  index: ValidatorIndex | null
+): index is ValidatorIndex {
+  return index !== null && index < state.validators.length;
+}