eth/filters: fast error if len(topics) > 4

Signed-off-by: jsvisa <delweng@gmail.com>

eth/filters/api.go

@@ -29,6 +29,7 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/internal/ethapi"
 	"github.com/ethereum/go-ethereum/rpc"
 )
@@ -39,6 +40,9 @@ var (
 	errInvalidBlockRange = errors.New("invalid block range params")
 )
 
+// The maximum number of topic criteria allowed
+const maxTopics = int(vm.LOG4 - vm.LOG0)
+
 // filter is a helper struct that holds meta information over the filter type
 // and associated subscription in the event system.
 type filter struct {
@@ -334,6 +338,9 @@ func (api *FilterAPI) NewFilter(crit FilterCriteria) (rpc.ID, error) {
 
 // GetLogs returns logs matching the given argument that are stored within the state.
 func (api *FilterAPI) GetLogs(ctx context.Context, crit FilterCriteria) ([]*types.Log, error) {
+	if len(crit.Topics) > maxTopics {
+		return nil, errInvalidTopic
+	}
 	var filter *Filter
 	if crit.BlockHash != nil {
 		// Block filter requested, construct a single-shot filter

eth/filters/filter_system.go

@@ -299,6 +299,9 @@ func (es *EventSystem) subscribe(sub *subscription) *Subscription {
 // given criteria to the given logs channel. Default value for the from and to
 // block is "latest". If the fromBlock > toBlock an error is returned.
 func (es *EventSystem) SubscribeLogs(crit ethereum.FilterQuery, logs chan []*types.Log) (*Subscription, error) {
+	if len(crit.Topics) > maxTopics {
+		return nil, errInvalidTopic
+	}
 	var from, to rpc.BlockNumber
 	if crit.FromBlock == nil {
 		from = rpc.LatestBlockNumber