No length check in AggregatePublicKeys (#9105)

* check of len and nil

* minor edit

* minor edit

Co-authored-by: terence tsao <terence@prysmaticlabs.com>

shared/bls/blst/public_key.go

@@ -57,6 +57,9 @@ func AggregatePublicKeys(pubs [][]byte) (common.PublicKey, error) {
 	if featureconfig.Get().SkipBLSVerify {
 		return &PublicKey{}, nil
 	}
+	if pubs == nil || len(pubs) == 0 {
+		return nil, errors.New("nil or empty public keys")
+	}
 	agg := new(blstAggregatePublicKey)
 	mulP1 := make([]*blstPublicKey, 0, len(pubs))
 	for _, pubkey := range pubs {

shared/bls/blst/public_key_test.go

@@ -76,3 +76,9 @@ func TestPublicKey_Copy(t *testing.T) {
 
 	require.DeepEqual(t, pubkeyA.Marshal(), pubkeyBytes, "Pubkey was mutated after copy")
 }
+
+func TestPublicKeysEmpty(t *testing.T) {
+	pubs := [][]byte{}
+	_, err := blst.AggregatePublicKeys(pubs)
+	require.ErrorContains(t, "nil or empty public keys", err)
+}