From b4f41116093d3c07695898f4d298205d51908243 Mon Sep 17 00:00:00 2001
From: Andrey Meshkov <am@adguard.com>
Date: Mon, 23 Dec 2019 15:59:49 +0300
Subject: [PATCH] -(dnsfilter): match DNS response against filtering rules only

Supposedly, this will fix #1290
---
 dnsfilter/dnsfilter.go   | 12 +++++++++++-
 dnsforward/dnsforward.go |  6 +++---
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/dnsfilter/dnsfilter.go b/dnsfilter/dnsfilter.go
index ae91164f..7f7034a8 100644
--- a/dnsfilter/dnsfilter.go
+++ b/dnsfilter/dnsfilter.go
@@ -263,7 +263,17 @@ func (r Reason) Matched() bool {
 	return r != NotFilteredNotFound
 }
 
-// CheckHost tries to match host against rules, then safebrowsing and parental if they are enabled
+// CheckHostRules tries to match the host against filtering rules only
+func (d *Dnsfilter) CheckHostRules(host string, qtype uint16, setts *RequestFilteringSettings) (Result, error) {
+	if !setts.FilteringEnabled {
+		return Result{}, nil
+	}
+
+	return d.matchHost(host, qtype)
+}
+
+// CheckHost tries to match the host against filtering rules,
+// then safebrowsing and parental if they are enabled
 func (d *Dnsfilter) CheckHost(host string, qtype uint16, setts *RequestFilteringSettings) (Result, error) {
 	// sometimes DNS clients will try to resolve ".", which is a request to get root servers
 	if host == "" {
diff --git a/dnsforward/dnsforward.go b/dnsforward/dnsforward.go
index 0b4e5081..0af717be 100644
--- a/dnsforward/dnsforward.go
+++ b/dnsforward/dnsforward.go
@@ -492,7 +492,7 @@ func (s *Server) handleDNSRequest(p *proxy.Proxy, d *proxy.DNSContext) error {
 
 		} else if res.Reason != dnsfilter.NotFilteredWhiteList {
 			origResp2 := d.Res
-			res, err = s.filterResponse(d)
+			res, err = s.filterDNSResponse(d)
 			if err != nil {
 				return err
 			}
@@ -652,7 +652,7 @@ func (s *Server) filterDNSRequest(d *proxy.DNSContext) (*dnsfilter.Result, error
 
 // If response contains CNAME, A or AAAA records, we apply filtering to each canonical host name or IP address.
 // If this is a match, we set a new response in d.Res and return.
-func (s *Server) filterResponse(d *proxy.DNSContext) (*dnsfilter.Result, error) {
+func (s *Server) filterDNSResponse(d *proxy.DNSContext) (*dnsfilter.Result, error) {
 	for _, a := range d.Res.Answer {
 		host := ""
 
@@ -681,7 +681,7 @@ func (s *Server) filterResponse(d *proxy.DNSContext) (*dnsfilter.Result, error)
 			continue
 		}
 		setts := s.getClientRequestFilteringSettings(d)
-		res, err := s.dnsFilter.CheckHost(host, d.Req.Question[0].Qtype, setts)
+		res, err := s.dnsFilter.CheckHostRules(host, d.Req.Question[0].Qtype, setts)
 		s.RUnlock()
 
 		if err != nil {