fix nil panic error when sshFxpExtendedPacket could not UnmarshalBinary ExtendedRequest

LeeEirc · LeeEirc · commit 3f23d5935f77 · 2019-10-11T14:31:08.000+08:00
diff --git a/request-server.go b/request-server.go
@@ -159,7 +159,9 @@ func (rs *RequestServer) packetWorker(
 ) error {
 	for pkt := range pktChan {
 		if epkt, ok := pkt.requestPacket.(*sshFxpExtendedPacket); ok {
-			pkt.requestPacket = epkt.SpecificPacket
+			if epkt.SpecificPacket != nil {
+				pkt.requestPacket = epkt.SpecificPacket
+			}
 		}
 
 		var rpkt responsePacket
