Drop NSEC3 zone (#120)

Error out when parsing and transferring such a zone. If we would serve
it we would give out the wrong answers, leading to (probably) validation
failures...

Fixes #114

middleware/file/file.go

@@ -108,19 +108,25 @@ func Parse(f io.Reader, origin, fileName string) (*Zone, error) {
 	z := NewZone(origin)
 	for x := range tokens {
 		if x.Error != nil {
-			log.Printf("[ERROR] Failed to parse %s: %v", origin, x.Error)
+			log.Printf("[ERROR] Failed to parse `%s': %v", origin, x.Error)
 			return nil, x.Error
 		}
-		if x.RR.Header().Rrtype == dns.TypeSOA {
+		switch h := x.RR.Header().Rrtype; h {
+		case dns.TypeSOA:
 			z.SOA = x.RR.(*dns.SOA)
-			continue
-		}
-		if x.RR.Header().Rrtype == dns.TypeRRSIG {
+		case dns.TypeNSEC3, dns.TypeNSEC3PARAM:
+			err := fmt.Errorf("NSEC3 zone is not supported, dropping")
+			log.Printf("[ERROR] Failed to parse `%s': %v", origin, err)
+			return nil, err
+		case dns.TypeRRSIG:
 			if x, ok := x.RR.(*dns.RRSIG); ok && x.TypeCovered == dns.TypeSOA {
 				z.SIG = append(z.SIG, x)
+				continue
 			}
+			fallthrough
+		default:
+			z.Insert(x.RR)
 		}
-		z.Insert(x.RR)
 	}
 	return z, nil
 }

middleware/file/nsec3_test.go

+package file
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestParseNSEC3(t *testing.T) {
+	_, err := Parse(strings.NewReader(nsec3_test), "miek.nl", "stdin")
+	if err == nil {
+		t.Fatalf("expected error when reading zone, got nothing")
+	}
+}
+
+const nsec3_test = `miek.nl.		1800	IN	SOA	linode.atoom.net. miek.miek.nl. 1460175181 14400 3600 604800 14400
+miek.nl.		1800	IN	NS	omval.tednet.nl.
+miek.nl.		1800	IN	NS	linode.atoom.net.
+miek.nl.		1800	IN	NS	ext.ns.whyscream.net.
+miek.nl.		1800	IN	NS	ns-ext.nlnetlabs.nl.
+miek.nl.		0	IN	NSEC3PARAM 1 0 5 A3DEBC9CC4F695C7`

middleware/file/secondary.go

 package file
 
 import (
+	"fmt"
 	"log"
 	"time"
 
@@ -28,27 +29,33 @@ Transfer:
 		t := new(dns.Transfer)
 		c, err := t.In(m, tr)
 		if err != nil {
-			log.Printf("[ERROR] Failed to setup transfer %s with %s: %v", z.name, tr, err)
+			log.Printf("[ERROR] Failed to setup transfer `%s' with `%s': %v", z.name, tr, err)
 			Err = err
 			continue Transfer
 		}
 		for env := range c {
 			if env.Error != nil {
-				log.Printf("[ERROR] Failed to parse transfer %s: %v", z.name, env.Error)
+				log.Printf("[ERROR] Failed to parse transfer `%s': %v", z.name, env.Error)
 				Err = env.Error
 				continue Transfer
 			}
 			for _, rr := range env.RR {
-				if rr.Header().Rrtype == dns.TypeSOA {
+				switch h := rr.Header().Rrtype; h {
+				case dns.TypeSOA:
 					z1.SOA = rr.(*dns.SOA)
-					continue
-				}
-				if rr.Header().Rrtype == dns.TypeRRSIG {
+				case dns.TypeNSEC3, dns.TypeNSEC3PARAM:
+					err := fmt.Errorf("NSEC3 zone is not supported, dropping")
+					log.Printf("[ERROR] Failed to parse transfer `%s': %v", z.name, err)
+					return err
+				case dns.TypeRRSIG:
 					if x, ok := rr.(*dns.RRSIG); ok && x.TypeCovered == dns.TypeSOA {
 						z1.SIG = append(z1.SIG, x)
+						continue
 					}
+					fallthrough
+				default:
+					z1.Insert(rr)
 				}
-				z1.Insert(rr)
 			}
 		}
 		Err = nil