From d2979cfb4f2357895458bebce5ac3248bbbfa2b9 Mon Sep 17 00:00:00 2001
From: Jukka Taimisto <jtaimisto@gmail.com>
Date: Wed, 9 Feb 2022 11:05:10 +0200
Subject: [PATCH] Add length check before reading label pointer

---
 dnsutils/dns.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/dnsutils/dns.go b/dnsutils/dns.go
index 7ba72060..b15f9e5f 100644
--- a/dnsutils/dns.go
+++ b/dnsutils/dns.go
@@ -342,6 +342,9 @@ func _ParseLabels(offset int, payload []byte, pointers map[uint16]int) (string,
 		}
 		// label pointer support ?
 		if length>>6 == 3 {
+			if offset+1 >= len(payload) {
+				return "", 0, ErrDecodeDnsLabelTooShort
+			}
 			ptr := binary.BigEndian.Uint16(payload[offset:offset+2]) & 16383
 			_, exist := pointers[ptr]
 			if exist {