From 4f5f89b6e1a6cacfdadd7c421e65be2ab307a983 Mon Sep 17 00:00:00 2001
From: Simone Margaritelli <evilsocket@gmail.com>
Date: Tue, 23 Mar 2021 19:22:05 +0100
Subject: [PATCH] fix: do not add unhandled dns types to dns spoofing packets
 (closes #843)

---
 modules/dns_spoof/dns_spoof.go | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/modules/dns_spoof/dns_spoof.go b/modules/dns_spoof/dns_spoof.go
index 8302474c..ab9a350a 100644
--- a/modules/dns_spoof/dns_spoof.go
+++ b/modules/dns_spoof/dns_spoof.go
@@ -192,6 +192,13 @@ func DnsReply(s *session.Session, TTL uint32, pkt gopacket.Packet, peth *layers.
 
 	answers := make([]layers.DNSResourceRecord, 0)
 	for _, q := range req.Questions {
+		// do not include types we can't handle and that are not needed
+		// for successful spoofing anyway
+		// ref: https://github.com/bettercap/bettercap/issues/843
+		if q.Type.String() == "Unknown" {
+			continue
+		}
+
 		answers = append(answers,
 			layers.DNSResourceRecord{
 				Name:  []byte(q.Name),
@@ -231,7 +238,7 @@ func DnsReply(s *session.Session, TTL uint32, pkt gopacket.Packet, peth *layers.
 
 		err, raw = packets.Serialize(&eth, &ip6, &udp, &dns)
 		if err != nil {
-			log.Error("error serializing packet: %s.", err)
+			log.Error("error serializing ipv6 packet: %s.", err)
 			return "", ""
 		}
 	} else {
@@ -252,7 +259,7 @@ func DnsReply(s *session.Session, TTL uint32, pkt gopacket.Packet, peth *layers.
 
 		err, raw = packets.Serialize(&eth, &ip4, &udp, &dns)
 		if err != nil {
-			log.Error("error serializing packet: %s.", err)
+			log.Error("error serializing ipv4 packet: %s.", err)
 			return "", ""
 		}
 	}