eth/gasprice: add query limit for FeeHistory to defend DDOS attack (#…

…29644)

* eth/gasprice: add query limit for FeeHistory to defend DDOS attack

* fix return values after cherry-pick

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Co-authored-by: Eric <45141191+zlacfzy@users.noreply.github.com>

eth/gasprice/feehistory.go

@@ -44,6 +44,7 @@ const (
 	// maxBlockFetchers is the max number of goroutines to spin up to pull blocks
 	// for the fee history calculation (mostly relevant for LES).
 	maxBlockFetchers = 4
+	maxQueryLimit    = 100
 )
 
 // blockFees represents a single block for processing
@@ -240,6 +241,9 @@ func (oracle *Oracle) FeeHistory(ctx context.Context, blocks uint64, unresolvedL
 	if len(rewardPercentiles) != 0 {
 		maxFeeHistory = oracle.maxBlockHistory
 	}
+	if len(rewardPercentiles) > maxQueryLimit {
+		return common.Big0, nil, nil, nil, nil, nil, fmt.Errorf("%w: over the query limit %d", errInvalidPercentile, maxQueryLimit)
+	}
 	if blocks > maxFeeHistory {
 		log.Warn("Sanitizing fee history length", "requested", blocks, "truncated", maxFeeHistory)
 		blocks = maxFeeHistory