From 0848ca0e69e3c535b70e2d1f7e8c24f0e1941ee9 Mon Sep 17 00:00:00 2001
From: Simon Zolin <s.zolin@adguard.com>
Date: Thu, 21 May 2020 14:48:31 +0300
Subject: [PATCH] - rewrites: fix crash when handling name->cname->A chain

crash.adguard -> adguard.a.record
adguard.a.record -> 1.2.3.4
---
 dnsforward/handle_dns.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/dnsforward/handle_dns.go b/dnsforward/handle_dns.go
index 8478c426..7aabd25e 100644
--- a/dnsforward/handle_dns.go
+++ b/dnsforward/handle_dns.go
@@ -211,6 +211,9 @@ func processFilteringAfterResponse(ctx *dnsContext) int {
 
 	switch res.Reason {
 	case dnsfilter.ReasonRewrite:
+		if d.Res != nil {
+			break // response is already prepared
+		}
 		if len(res.CanonName) == 0 {
 			break
 		}