plugin/dnssec; insert and sign DS records (#1153)

* plugin/dnssec; insert and sign DS records

Sign a delegation as well and insert DS records.

Fixes #698

* better

plugin/dnssec/dnskey.go

@@ -15,9 +15,10 @@ import (
 
 // DNSKEY holds a DNSSEC public and private key used for on-the-fly signing.
 type DNSKEY struct {
-	K      *dns.DNSKEY
-	s      crypto.Signer
-	keytag uint16
+	K   *dns.DNSKEY
+	D   *dns.DS
+	s   crypto.Signer
+	tag uint16
 }
 
 // ParseKeyFile read a DNSSEC keyfile as generated by dnssec-keygen or other
@@ -36,18 +37,20 @@ func ParseKeyFile(pubFile, privFile string) (*DNSKEY, error) {
 	if e != nil {
 		return nil, e
 	}
-	p, e := k.(*dns.DNSKEY).ReadPrivateKey(f, privFile)
+
+	dk := k.(*dns.DNSKEY)
+	p, e := dk.ReadPrivateKey(f, privFile)
 	if e != nil {
 		return nil, e
 	}
 
-	if v, ok := p.(*rsa.PrivateKey); ok {
-		return &DNSKEY{k.(*dns.DNSKEY), v, k.(*dns.DNSKEY).KeyTag()}, nil
+	if s, ok := p.(*rsa.PrivateKey); ok {
+		return &DNSKEY{K: dk, D: dk.ToDS(dns.SHA256), s: s, tag: dk.KeyTag()}, nil
 	}
-	if v, ok := p.(*ecdsa.PrivateKey); ok {
-		return &DNSKEY{k.(*dns.DNSKEY), v, k.(*dns.DNSKEY).KeyTag()}, nil
+	if s, ok := p.(*ecdsa.PrivateKey); ok {
+		return &DNSKEY{K: dk, D: dk.ToDS(dns.SHA256), s: s, tag: dk.KeyTag()}, nil
 	}
-	return &DNSKEY{k.(*dns.DNSKEY), nil, 0}, errors.New("no known? private key found")
+	return &DNSKEY{K: dk, D: dk.ToDS(dns.SHA256), s: nil, tag: 0}, errors.New("no known private key found")
 }
 
 // getDNSKEY returns the correct DNSKEY to the client. Signatures are added when do is true.

plugin/dnssec/dnssec.go

@@ -35,20 +35,30 @@ func New(zones []string, keys []*DNSKEY, next plugin.Handler, c *cache.Cache) Dn
 }
 
 // Sign signs the message in state. it takes care of negative or nodata responses. It
-// uses NSEC black lies for authenticated denial of existence. Signatures
-// creates will be cached for a short while. By default we sign for 8 days,
+// uses NSEC black lies for authenticated denial of existence. For delegations it
+// will insert DS records and sign those.
+// Signatures will be cached for a short while. By default we sign for 8 days,
 // starting 3 hours ago.
 func (d Dnssec) Sign(state request.Request, zone string, now time.Time) *dns.Msg {
 	req := state.Req
 
+	incep, expir := incepExpir(now)
+
 	mt, _ := response.Typify(req, time.Now().UTC()) // TODO(miek): need opt record here?
 	if mt == response.Delegation {
-		// TODO(miek): uh, signing DS record?!?!
+		ttl := req.Ns[0].Header().Ttl
+
+		ds := []dns.RR{}
+		for i := range d.keys {
+			ds = append(ds, d.keys[i].D)
+		}
+		if sigs, err := d.sign(ds, zone, ttl, incep, expir); err == nil {
+			req.Ns = append(req.Ns, ds...)
+			req.Ns = append(req.Ns, sigs...)
+		}
 		return req
 	}
 
-	incep, expir := incepExpir(now)
-
 	if mt == response.NameError || mt == response.NoData {
 		if req.Ns[0].Header().Rrtype != dns.TypeSOA || len(req.Ns) > 1 {
 			return req

plugin/dnssec/dnssec_test.go

@@ -21,10 +21,10 @@ func TestZoneSigning(t *testing.T) {
 
 	m = d.Sign(state, "miek.nl.", time.Now().UTC())
 	if !section(m.Answer, 1) {
-		t.Errorf("answer section should have 1 sig")
+		t.Errorf("Answer section should have 1 RRSIG")
 	}
 	if !section(m.Ns, 1) {
-		t.Errorf("authority section should have 1 sig")
+		t.Errorf("Authority section should have 1 RRSIG")
 	}
 }
 
@@ -40,7 +40,7 @@ func TestZoneSigningDouble(t *testing.T) {
 
 	key1, err := ParseKeyFile(fPub1, fPriv1)
 	if err != nil {
-		t.Fatalf("failed to parse key: %v\n", err)
+		t.Fatalf("Failed to parse key: %v\n", err)
 	}
 	d.keys = append(d.keys, key1)
 
@@ -48,10 +48,10 @@ func TestZoneSigningDouble(t *testing.T) {
 	state := request.Request{Req: m}
 	m = d.Sign(state, "miek.nl.", time.Now().UTC())
 	if !section(m.Answer, 2) {
-		t.Errorf("answer section should have 1 sig")
+		t.Errorf("Answer section should have 1 RRSIG")
 	}
 	if !section(m.Ns, 2) {
-		t.Errorf("authority section should have 1 sig")
+		t.Errorf("Authority section should have 1 RRSIG")
 	}
 }
 
@@ -64,7 +64,7 @@ func TestSigningDifferentZone(t *testing.T) {
 
 	key, err := ParseKeyFile(fPub, fPriv)
 	if err != nil {
-		t.Fatalf("failed to parse key: %v\n", err)
+		t.Fatalf("Failed to parse key: %v\n", err)
 	}
 
 	m := testMsgEx()
@@ -73,11 +73,11 @@ func TestSigningDifferentZone(t *testing.T) {
 	d := New([]string{"example.org."}, []*DNSKEY{key}, nil, c)
 	m = d.Sign(state, "example.org.", time.Now().UTC())
 	if !section(m.Answer, 1) {
-		t.Errorf("answer section should have 1 sig")
+		t.Errorf("Answer section should have 1 RRSIG")
 		t.Logf("%+v\n", m)
 	}
 	if !section(m.Ns, 1) {
-		t.Errorf("authority section should have 1 sig")
+		t.Errorf("Authority section should have 1 RRSIG")
 		t.Logf("%+v\n", m)
 	}
 }
@@ -91,7 +91,7 @@ func TestSigningCname(t *testing.T) {
 	state := request.Request{Req: m}
 	m = d.Sign(state, "miek.nl.", time.Now().UTC())
 	if !section(m.Answer, 1) {
-		t.Errorf("answer section should have 1 sig")
+		t.Errorf("Answer section should have 1 RRSIG")
 	}
 }
 
@@ -103,12 +103,24 @@ func TestZoneSigningDelegation(t *testing.T) {
 	m := testDelegationMsg()
 	state := request.Request{Req: m}
 	m = d.Sign(state, "miek.nl.", time.Now().UTC())
-	if !section(m.Ns, 0) {
-		t.Errorf("authority section should have 0 sig")
+	if !section(m.Ns, 1) {
+		t.Errorf("Authority section should have 1 RRSIG")
 		t.Logf("%v\n", m)
 	}
+
+	ds := 0
+	for i := range m.Ns {
+		if _, ok := m.Ns[i].(*dns.DS); ok {
+			ds++
+		}
+	}
+	if ds != 1 {
+		t.Errorf("Authority section should have 1 DS")
+		t.Logf("%v\n", m)
+
+	}
 	if !section(m.Extra, 0) {
-		t.Errorf("answer section should have 0 sig")
+		t.Errorf("Answer section should have 0 RRSIGs")
 		t.Logf("%v\n", m)
 	}
 }
@@ -123,7 +135,7 @@ func TestSigningDname(t *testing.T) {
 	// We sign *everything* we see, also the synthesized CNAME.
 	m = d.Sign(state, "miek.nl.", time.Now().UTC())
 	if !section(m.Answer, 3) {
-		t.Errorf("answer section should have 3 sig")
+		t.Errorf("Answer section should have 3 RRSIGs")
 	}
 }
 
@@ -137,7 +149,7 @@ func TestSigningEmpty(t *testing.T) {
 	state := request.Request{Req: m}
 	m = d.Sign(state, "miek.nl.", time.Now().UTC())
 	if !section(m.Ns, 2) {
-		t.Errorf("authority section should have 2 sig")
+		t.Errorf("Authority section should have 2 RRSIGs")
 	}
 }
 

plugin/dnssec/responsewriter.go

@@ -22,8 +22,7 @@ func (d *ResponseWriter) WriteMsg(res *dns.Msg) error {
 	// which zone it should be.
 	state := request.Request{W: d.ResponseWriter, Req: res}
 
-	qname := state.Name()
-	zone := plugin.Zones(d.d.zones).Matches(qname)
+	zone := plugin.Zones(d.d.zones).Matches(state.Name())
 	if zone == "" {
 		return d.ResponseWriter.WriteMsg(res)
 	}

plugin/dnssec/rrsig.go

@@ -8,7 +8,7 @@ func (k *DNSKEY) newRRSIG(signerName string, ttl, incep, expir uint32) *dns.RRSI
 
 	sig.Hdr.Rrtype = dns.TypeRRSIG
 	sig.Algorithm = k.K.Algorithm
-	sig.KeyTag = k.keytag
+	sig.KeyTag = k.tag
 	sig.SignerName = signerName
 	sig.Hdr.Ttl = ttl
 	sig.OrigTtl = origTTL

plugin/dnssec/setup.go

@@ -77,7 +77,7 @@ func dnssecParse(c *caddy.Controller) ([]string, []*DNSKEY, int, error) {
 		zones[i] = plugin.Host(zones[i]).Normalize()
 	}
 
-	// Check if each keys owner name can actually sign the zones we want them to sign
+	// Check if each keys owner name can actually sign the zones we want them to sign.
 	for _, k := range keys {
 		kname := plugin.Name(k.K.Header().Name)
 		ok := false
@@ -88,7 +88,7 @@ func dnssecParse(c *caddy.Controller) ([]string, []*DNSKEY, int, error) {
 			}
 		}
 		if !ok {
-			return zones, keys, capacity, fmt.Errorf("key %s (keyid: %d) can not sign any of the zones", string(kname), k.keytag)
+			return zones, keys, capacity, fmt.Errorf("key %s (keyid: %d) can not sign any of the zones", string(kname), k.tag)
 		}
 	}