From 2dc0ae743bc1f0a0c3c41b6f725d2fc90c6b00f6 Mon Sep 17 00:00:00 2001
From: tony <tony.li@vechain.com>
Date: Mon, 30 Jul 2018 15:04:45 +0800
Subject: [PATCH] p2p/discv5: fix idx can be negative after uint convert to
 int(can cause crash)

---
 p2p/discv5/net.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/p2p/discv5/net.go b/p2p/discv5/net.go
index 9b0bd0c80a..4c39c05533 100644
--- a/p2p/discv5/net.go
+++ b/p2p/discv5/net.go
@@ -1228,7 +1228,7 @@ func (net *Network) checkTopicRegister(data *topicRegister) (*pong, error) {
 	if rlpHash(data.Topics) != pongpkt.data.(*pong).TopicHash {
 		return nil, errors.New("topic hash mismatch")
 	}
-	if data.Idx < 0 || int(data.Idx) >= len(data.Topics) {
+	if int(data.Idx) < 0 || int(data.Idx) >= len(data.Topics) {
 		return nil, errors.New("topic index out of range")
 	}
 	return pongpkt.data.(*pong), nil