middleware/file: add DNSSEC support (#697)

* middleware/file: add DNSSEC support

Add tests for DNSSEC and check if everything is working.

* add signatures

* tweak

* Add DNSSEC signing tests for DNAME

* Just sign it all

4 files changed, 207 insertions, 2 deletions

diff --git a/middleware/dnssec/dnssec.go b/middleware/dnssec/dnssec.go
index a0a072349..7ad5f2bf7 100644
--- a/middleware/dnssec/dnssec.go
+++ b/middleware/dnssec/dnssec.go
@@ -43,6 +43,7 @@ func (d Dnssec) Sign(state request.Request, zone string, now time.Time) *dns.Msg
 
 	mt, _ := response.Typify(req, time.Now().UTC()) // TODO(miek): need opt record here?
 	if mt == response.Delegation {
+		// TODO(miek): uh, signing DS record?!?!
 		return req
 	}
 
diff --git a/middleware/dnssec/dnssec_test.go b/middleware/dnssec/dnssec_test.go
index 037dfbdd7..1c9c9a545 100644
--- a/middleware/dnssec/dnssec_test.go
+++ b/middleware/dnssec/dnssec_test.go
@@ -113,6 +113,20 @@ func TestZoneSigningDelegation(t *testing.T) {
 	}
 }
 
+func TestSigningDname(t *testing.T) {
+	d, rm1, rm2 := newDnssec(t, []string{"miek.nl."})
+	defer rm1()
+	defer rm2()
+
+	m := testMsgDname()
+	state := request.Request{Req: m}
+	// 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")
+	}
+}
+
 func section(rss []dns.RR, nrSigs int) bool {
 	i := 0
 	for _, r := range rss {
@@ -157,6 +171,16 @@ func testDelegationMsg() *dns.Msg {
 	}
 }
 
+func testMsgDname() *dns.Msg {
+	return &dns.Msg{
+		Answer: []dns.RR{
+			test.CNAME("a.dname.miek.nl.	1800	IN	CNAME	a.test.miek.nl."),
+			test.A("a.test.miek.nl.	1800	IN	A	139.162.196.78"),
+			test.DNAME("dname.miek.nl.	1800	IN	DNAME	test.miek.nl."),
+		},
+	}
+}
+
 func newDnssec(t *testing.T, zones []string) (Dnssec, func(), func()) {
 	k, rm1, rm2 := newKey(t)
 	cache, _ := lru.New(defaultCap)
diff --git a/middleware/file/dname_test.go b/middleware/file/dname_test.go
index e26a1c29a..04fb3ded7 100644
--- a/middleware/file/dname_test.go
+++ b/middleware/file/dname_test.go
@@ -130,6 +130,75 @@ func TestLookupDNAME(t *testing.T) {
 	}
 }
 
+var dnameDnssecTestCases = []test.Case{
+	{
+		// We have no auth section, because the test zone does not have nameservers.
+		Qname: "ns.example.org.", Qtype: dns.TypeA,
+		Answer: []dns.RR{
+			test.A("ns.example.org.	1800	IN	A	127.0.0.1"),
+		},
+	},
+	{
+		Qname: "dname.example.org.", Qtype: dns.TypeDNAME,
+		Do: true,
+		Answer: []dns.RR{
+			test.DNAME("dname.example.org.	1800	IN	DNAME	test.example.org."),
+			test.RRSIG("dname.example.org.	1800	IN	RRSIG	DNAME 5 3 1800 20170702091734 20170602091734 54282 example.org. HvXtiBM="),
+		},
+		Extra: []dns.RR{test.OPT(4096, true)},
+	},
+	{
+		Qname: "a.dname.example.org.", Qtype: dns.TypeA,
+		Do: true,
+		Answer: []dns.RR{
+			test.CNAME("a.dname.example.org.	1800	IN	CNAME	a.test.example.org."),
+			test.DNAME("dname.example.org.	1800	IN	DNAME	test.example.org."),
+			test.RRSIG("dname.example.org.	1800	IN	RRSIG	DNAME 5 3 1800 20170702091734 20170602091734 54282 example.org. HvXtiBM="),
+		},
+		Extra: []dns.RR{test.OPT(4096, true)},
+	},
+}
+
+func TestLookupDNAMEDNSSEC(t *testing.T) {
+	zone, err := Parse(strings.NewReader(dbExampleDNAMESigned), testzone, "stdin")
+	if err != nil {
+		t.Fatalf("Expect no error when reading zone, got %q", err)
+	}
+
+	fm := File{Next: test.ErrorHandler(), Zones: Zones{Z: map[string]*Zone{"example.org.": zone}, Names: []string{"example.org."}}}
+	ctx := context.TODO()
+
+	for _, tc := range dnameDnssecTestCases {
+		m := tc.Msg()
+
+		rec := dnsrecorder.New(&test.ResponseWriter{})
+		_, err := fm.ServeDNS(ctx, rec, m)
+		if err != nil {
+			t.Errorf("Expected no error, got %v\n", err)
+			return
+		}
+
+		resp := rec.Msg
+		sort.Sort(test.RRSet(resp.Answer))
+		sort.Sort(test.RRSet(resp.Ns))
+		sort.Sort(test.RRSet(resp.Extra))
+
+		if !test.Header(t, tc, resp) {
+			t.Logf("%v\n", resp)
+			continue
+		}
+		if !test.Section(t, tc, test.Answer, resp.Answer) {
+			t.Logf("%v\n", resp)
+		}
+		if !test.Section(t, tc, test.Ns, resp.Ns) {
+			t.Logf("%v\n", resp)
+		}
+		if !test.Section(t, tc, test.Extra, resp.Extra) {
+			t.Logf("%v\n", resp)
+		}
+	}
+}
+
 const dbMiekNLDNAME = `
 $TTL    30M
 $ORIGIN miek.nl.
@@ -157,3 +226,108 @@ dname           IN      DNAME   test
 dname           IN      A       127.0.0.1
 a.dname         IN      A       127.0.0.1
 `
+
+const dbExampleDNAMESigned = `
+; File written on Fri Jun  2 10:17:34 2017
+; dnssec_signzone version 9.10.3-P4-Debian
+example.org.		1800	IN SOA	a.example.org. b.example.org. (
+					1282630057 ; serial
+					14400      ; refresh (4 hours)
+					3600       ; retry (1 hour)
+					604800     ; expire (1 week)
+					14400      ; minimum (4 hours)
+					)
+			1800	RRSIG	SOA 5 2 1800 (
+					20170702091734 20170602091734 54282 example.org.
+					mr5eQtFs1GubgwaCcqrpiF6Cgi822OkESPeV
+					X0OJYq3JzthJjHw8TfYAJWQ2yGqhlePHir9h
+					FT/uFZdYyytHq+qgIUbJ9IVCrq0gZISZdHML
+					Ry1DNffMR9CpD77KocOAUABfopcvH/3UGOHn
+					TFxkAr447zPaaoC68JYGxYLfZk8= )
+			1800	NS	ns.example.org.
+			1800	RRSIG	NS 5 2 1800 (
+					20170702091734 20170602091734 54282 example.org.
+					McM4UdMxkscVQkJnnEbdqwyjpPgq5a/EuOLA
+					r2MvG43/cwOaWULiZoNzLi5Rjzhf+GTeVTan
+					jw6EsL3gEuYI1nznwlLQ04/G0XAHjbq5VvJc
+					rlscBD+dzf774yfaTjRNoeo2xTem6S7nyYPW
+					Y+1f6xkrsQPLYJfZ6VZ9QqyupBw= )
+			14400	NSEC	dname.example.org. NS SOA RRSIG NSEC DNSKEY
+			14400	RRSIG	NSEC 5 2 14400 (
+					20170702091734 20170602091734 54282 example.org.
+					VT+IbjDFajM0doMKFipdX3+UXfCn3iHIxg5x
+					LElp4Q/YddTbX+6tZf53+EO+G8Kye3JDLwEl
+					o8VceijNeF3igZ+LiZuXCei5Qg/TJ7IAUnAO
+					xd85IWwEYwyKkKd6Z2kXbAN2pdcHE8EmboQd
+					wfTr9oyWhpZk1Z+pN8vdejPrG0M= )
+			1800	DNSKEY	256 3 5 (
+					AwEAAczLlmTk5bMXUzpBo/Jta6MWSZYy3Nfw
+					gz8t/pkfSh4IlFF6vyXZhEqCeQsCBdD7ltkD
+					h5qd4A+nFrYOMwsi5XIjoHMlJN15xwFS9EgS
+					ZrZmuxePIEiYB5KccEf9JQMgM1t07Iu1FnrY
+					02OuAqGWcO4tuyTLaK3QP4MLQOfAgKqf
+					) ; ZSK; alg = RSASHA1; key id = 54282
+			1800	RRSIG	DNSKEY 5 2 1800 (
+					20170702091734 20170602091734 54282 example.org.
+					MBgSRtZ6idJblLIHxZWpWL/1oqIwImb1mkl7
+					hDFxqV6Hw19yLX06P7gcJEWiisdZBkVEfcOK
+					LeMJly05vgKfrMzLgIu2Ry4bL8AMKc8NMXBG
+					b1VDCEBW69P2omogj2KnORHDCZQr/BX9+wBU
+					5rIMTTKlMSI5sT6ecJHHEymtiac= )
+dname.example.org.	1800	IN A	127.0.0.1
+			1800	RRSIG	A 5 3 1800 (
+					20170702091734 20170602091734 54282 example.org.
+					LPCK2nLyDdGwvmzGLkUO2atEUjoc+aEspkC3
+					keZCdXZaLnAwBH7dNAjvvXzzy0WrgWeiyDb4
+					+rJ2N0oaKEZicM4QQDHKhugJblKbU5G4qTey
+					LSEaV3vvQnzGd0S6dCqnwfPj9czagFN7Zlf5
+					DmLtdxx0aiDPCUpqT0+H/vuGPfk= )
+			1800	DNAME	test.example.org.
+			1800	RRSIG	DNAME 5 3 1800 (
+					20170702091734 20170602091734 54282 example.org.
+					HvX79T1flWJ8H9/1XZjX6gz8rP/o2jbfPXJ9
+					vC7ids/ZJilSReabLru4DCqcw1IV2DM/CZdE
+					tBnED/T2PJXvMut9tnYMrz+ZFPxoV6XyA3Z7
+					bok3B0OuxizzAN2EXdol04VdbMHoWUzjQCzi
+					0Ri12zLGRPzDepZ7FolgD+JtiBM= )
+			14400	NSEC	a.dname.example.org. A DNAME RRSIG NSEC
+			14400	RRSIG	NSEC 5 3 14400 (
+					20170702091734 20170602091734 54282 example.org.
+					U3ZPYMUBJl3wF2SazQv/kBf6ec0CH+7n0Hr9
+					w6lBKkiXz7P9WQzJDVnTHEZOrbDI6UetFGyC
+					6qcaADCASZ9Wxc+riyK1Hl4ox+Y/CHJ97WHy
+					oS2X//vEf6qmbHQXin0WQtFdU/VCRYF40X5v
+					8VfqOmrr8iKiEqXND8XNVf58mTw= )
+a.dname.example.org.	1800	IN A	127.0.0.1
+			1800	RRSIG	A 5 4 1800 (
+					20170702091734 20170602091734 54282 example.org.
+					y7RHBWZwli8SJQ4BgTmdXmYS3KGHZ7AitJCx
+					zXFksMQtNoOfVEQBwnFqjAb8ezcV5u92h1gN
+					i1EcuxCFiElML1XFT8dK2GnlPAga9w3oIwd5
+					wzW/YHcnR0P9lF56Sl7RoIt6+jJqOdRfixS6
+					TDoLoXsNbOxQ+qV3B8pU2Tam204= )
+			14400	NSEC	ns.example.org. A RRSIG NSEC
+			14400	RRSIG	NSEC 5 4 14400 (
+					20170702091734 20170602091734 54282 example.org.
+					Tmu27q3+xfONSZZtZLhejBUVtEw+83ZU1AFb
+					Rsxctjry/x5r2JSxw/sgSAExxX/7tx/okZ8J
+					oJqtChpsr91Kiw3eEBgINi2lCYIpMJlW4cWz
+					8bYlHfR81VsKYgy/cRgrq1RRvBoJnw+nwSty
+					mKPIvUtt67LAvLxJheSCEMZLCKI= )
+ns.example.org.		1800	IN A	127.0.0.1
+			1800	RRSIG	A 5 3 1800 (
+					20170702091734 20170602091734 54282 example.org.
+					mhi1SGaaAt+ndQEg5uKWKCH0HMzaqh/9dUK3
+					p2wWMBrLbTZrcWyz10zRnvehicXDCasbBrer
+					ZpDQnz5AgxYYBURvdPfUzx1XbNuRJRE4l5PN
+					CEUTlTWcqCXnlSoPKEJE5HRf7v0xg2BrBUfM
+					4mZnW2bFLwjrRQ5mm/mAmHmTROk= )
+			14400	NSEC	example.org. A RRSIG NSEC
+			14400	RRSIG	NSEC 5 3 14400 (
+					20170702091734 20170602091734 54282 example.org.
+					loHcdjX+NIWLAkUDfPSy2371wrfUvrBQTfMO
+					17eO2Y9E/6PE935NF5bjQtZBRRghyxzrFJhm
+					vY1Ad5ZTb+NLHvdSWbJQJog+eCc7QWp64WzR
+					RXpMdvaE6ZDwalWldLjC3h8QDywDoFdndoRY
+					eHOsmTvvtWWqtO6Fa5A8gmHT5HA= )
+`
diff --git a/middleware/file/lookup.go b/middleware/file/lookup.go
index 9c5d95b06..5726adbcd 100644
--- a/middleware/file/lookup.go
+++ b/middleware/file/lookup.go
@@ -105,14 +105,20 @@ func (z *Zone) Lookup(state request.Request, qname string) ([]dns.RR, []dns.RR,
 
 		// If we see DNAME records, we should return those.
 		if dnamerrs := elem.Types(dns.TypeDNAME); dnamerrs != nil {
-			// Only one DNAME is allowed per name. We just pick the first one.
+			// Only one DNAME is allowed per name. We just pick the first one to synthesize from.
 			dname := dnamerrs[0]
 			if cname := synthesizeCNAME(state.Name(), dname.(*dns.DNAME)); cname != nil {
 				answer, ns, extra, rcode := z.searchCNAME(state, elem, []dns.RR{cname})
 
+				if do {
+					sigs := elem.Types(dns.TypeRRSIG)
+					sigs = signatureForSubType(sigs, dns.TypeDNAME)
+					dnamerrs = append(dnamerrs, sigs...)
+				}
+
 				// The relevant DNAME RR should be included in the answer section,
 				// if the DNAME is being employed as a substitution instruction.
-				answer = append([]dns.RR{dname}, answer...)
+				answer = append(dnamerrs, answer...)
 
 				return answer, ns, extra, rcode
 			}