eth/catalyst: add validation error in new paylaod hash mismatch (ethe…

…reum#28226)

* eth/catalyst: add validation error in new paylaod hash mismatch

* eth/catalyst/api: refactor api.invalid(..) to return nil latest valid hash if none provided

eth/catalyst/api.go

@@ -513,7 +513,7 @@ func (api *ConsensusAPI) newPayload(params engine.ExecutableData, versionedHashe
 	block, err := engine.ExecutableDataToBlock(params, versionedHashes, beaconRoot)
 	if err != nil {
 		log.Warn("Invalid NewPayload params", "params", params, "error", err)
-		return engine.PayloadStatusV1{Status: engine.INVALID}, nil
+		return api.invalid(err, nil), nil
 	}
 	// Stash away the last update to warn the user if the beacon client goes offline
 	api.lastNewPayloadLock.Lock()
@@ -694,20 +694,21 @@ func (api *ConsensusAPI) checkInvalidAncestor(check common.Hash, head common.Has
 	}
 }
 
-// invalid returns a response "INVALID" with the latest valid hash supplied by latest or to the current head
-// if no latestValid block was provided.
+// invalid returns a response "INVALID" with the latest valid hash supplied by latest.
 func (api *ConsensusAPI) invalid(err error, latestValid *types.Header) engine.PayloadStatusV1 {
-	currentHash := api.eth.BlockChain().CurrentBlock().Hash()
+	var currentHash *common.Hash
 	if latestValid != nil {
-		// Set latest valid hash to 0x0 if parent is PoW block
-		currentHash = common.Hash{}
-		if latestValid.Difficulty.BitLen() == 0 {
+		if latestValid.Difficulty.BitLen() != 0 {
+			// Set latest valid hash to 0x0 if parent is PoW block
+			currentHash = &common.Hash{}
+		} else {
 			// Otherwise set latest valid hash to parent hash
-			currentHash = latestValid.Hash()
+			h := latestValid.Hash()
+			currentHash = &h
 		}
 	}
 	errorMsg := err.Error()
-	return engine.PayloadStatusV1{Status: engine.INVALID, LatestValidHash: &currentHash, ValidationError: &errorMsg}
+	return engine.PayloadStatusV1{Status: engine.INVALID, LatestValidHash: currentHash, ValidationError: &errorMsg}
 }
 
 // heartbeat loops indefinitely, and checks if there have been beacon client updates