p2p/discover: validate bond against lastpong, not db presence

karalabe · karalabe · commit 32301a4d6b3a · 2018-02-16T17:05:08.000+02:00
diff --git a/p2p/discover/udp.go b/p2p/discover/udp.go
@@ -613,7 +613,7 @@ func (req *findnode) handle(t *udp, from *net.UDPAddr, fromID NodeID, mac []byte
 	if expired(req.Expiration) {
 		return errExpired
 	}
-	if t.db.node(fromID) == nil {
+	if age := time.Since(t.db.lastPong(fromID)); age > nodeDBNodeExpiration {
 		// No bond exists, we don't process the packet. This prevents
 		// an attack vector where the discovery protocol could be used
 		// to amplify traffic in a DDOS attack. A malicious actor

Original file line number	Diff line number	Diff line change
`@@ -613,7 +613,7 @@ func (req findnode) handle(t udp, from *net.UDPAddr, fromID NodeID, mac []byte`
`613`	`613`	`if expired(req.Expiration) {`
`614`	`614`	`return errExpired`
`615`	`615`	`}`
`616`		`- if t.db.node(fromID) == nil {`
	`616`	`+ if age := time.Since(t.db.lastPong(fromID)); age > nodeDBNodeExpiration {`
`617`	`617`	`// No bond exists, we don't process the packet. This prevents`
`618`	`618`	`// an attack vector where the discovery protocol could be used`
`619`	`619`	`// to amplify traffic in a DDOS attack. A malicious actor`