Issue 388 (#389)

* add extra test

* middleware/auto: fix crash when calling empty handler

Don't call the next middleware, we should be auth. for this zone
getitng into this path we should respond with ServFail.

Fixes #388

middleware/auto/auto.go

@@ -64,10 +64,7 @@ func (a Auto) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (i
 	z, ok := a.Zones.Z[zone]
 	a.Zones.RUnlock()
 
-	if !ok {
+	if !ok || z == nil {
-		return a.Next.ServeDNS(ctx, w, r)
-	}
-	if z == nil {
 		return dns.RcodeServerFailure, nil
 	}
 

middleware/file/file.go

@@ -43,11 +43,9 @@ func (f File) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (i
 		}
 		return dns.RcodeServerFailure, errors.New("no next middleware found")
 	}
+
 	z, ok := f.Zones.Z[zone]
-	if !ok {
+	if !ok || z == nil {
-		return f.Next.ServeDNS(ctx, w, r)
-	}
-	if z == nil {
 		return dns.RcodeServerFailure, nil
 	}
 

test/auto_test.go

@@ -79,6 +79,44 @@ func TestAuto(t *testing.T) {
 	}
 }
 
+func TestAutoNonExistentZone(t *testing.T) {
+	tmpdir, err := ioutil.TempDir(os.TempDir(), "coredns")
+	if err != nil {
+		t.Fatal(err)
+	}
+	log.SetOutput(ioutil.Discard)
+
+	corefile := `.:0 {
+		auto {
+			directory ` + tmpdir + ` (.*) {1} 1
+		}
+		errors stdout
+	}
+`
+
+	i, err := CoreDNSServer(corefile)
+	if err != nil {
+		t.Fatalf("Could not get CoreDNS serving instance: %s", err)
+	}
+
+	udp, _ := CoreDNSServerPorts(i, 0)
+	if udp == "" {
+		t.Fatalf("Could not get UDP listening port")
+	}
+	defer i.Stop()
+
+	p := proxy.New([]string{udp})
+	state := request.Request{W: &test.ResponseWriter{}, Req: new(dns.Msg)}
+
+	resp, err := p.Lookup(state, "example.org.", dns.TypeA)
+	if err != nil {
+		t.Fatal("Expected to receive reply, but didn't")
+	}
+	if resp.Rcode != dns.RcodeServerFailure {
+		t.Fatalf("Expected reply to be a SERVFAIL, got %d", resp.Rcode)
+	}
+}
+
 const zoneContent = `; testzone
 @	IN	SOA	sns.dns.icann.org. noc.dns.icann.org. 2016082534 7200 3600 1209600 3600
 		NS	a.iana-servers.net.