1// Copyright 2011 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package net
6
7import (
8	"encoding/hex"
9	"reflect"
10	"testing"
11)
12
13func TestStructPackUnpack(t *testing.T) {
14	want := dnsQuestion{
15		Name:   ".",
16		Qtype:  dnsTypeA,
17		Qclass: dnsClassINET,
18	}
19	buf := make([]byte, 50)
20	n, ok := packStruct(&want, buf, 0)
21	if !ok {
22		t.Fatal("packing failed")
23	}
24	buf = buf[:n]
25	got := dnsQuestion{}
26	n, ok = unpackStruct(&got, buf, 0)
27	if !ok {
28		t.Fatal("unpacking failed")
29	}
30	if n != len(buf) {
31		t.Errorf("unpacked different amount than packed: got n = %d, want = %d", n, len(buf))
32	}
33	if !reflect.DeepEqual(got, want) {
34		t.Errorf("got = %+v, want = %+v", got, want)
35	}
36}
37
38func TestDomainNamePackUnpack(t *testing.T) {
39	tests := []struct {
40		in   string
41		want string
42		ok   bool
43	}{
44		{"", ".", true},
45		{".", ".", true},
46		{"google..com", "", false},
47		{"google.com", "google.com.", true},
48		{"google..com.", "", false},
49		{"google.com.", "google.com.", true},
50		{".google.com.", "", false},
51		{"www..google.com.", "", false},
52		{"www.google.com.", "www.google.com.", true},
53	}
54
55	for _, test := range tests {
56		buf := make([]byte, 30)
57		n, ok := packDomainName(test.in, buf, 0)
58		if ok != test.ok {
59			t.Errorf("packing of %s: got ok = %t, want = %t", test.in, ok, test.ok)
60			continue
61		}
62		if !test.ok {
63			continue
64		}
65		buf = buf[:n]
66		got, n, ok := unpackDomainName(buf, 0)
67		if !ok {
68			t.Errorf("unpacking for %s failed", test.in)
69			continue
70		}
71		if n != len(buf) {
72			t.Errorf(
73				"unpacked different amount than packed for %s: got n = %d, want = %d",
74				test.in,
75				n,
76				len(buf),
77			)
78		}
79		if got != test.want {
80			t.Errorf("unpacking packing of %s: got = %s, want = %s", test.in, got, test.want)
81		}
82	}
83}
84
85func TestDNSPackUnpack(t *testing.T) {
86	want := dnsMsg{
87		question: []dnsQuestion{{
88			Name:   ".",
89			Qtype:  dnsTypeAAAA,
90			Qclass: dnsClassINET,
91		}},
92		answer: []dnsRR{},
93		ns:     []dnsRR{},
94		extra:  []dnsRR{},
95	}
96	b, ok := want.Pack()
97	if !ok {
98		t.Fatal("packing failed")
99	}
100	var got dnsMsg
101	ok = got.Unpack(b)
102	if !ok {
103		t.Fatal("unpacking failed")
104	}
105	if !reflect.DeepEqual(got, want) {
106		t.Errorf("got = %+v, want = %+v", got, want)
107	}
108}
109
110func TestDNSParseSRVReply(t *testing.T) {
111	data, err := hex.DecodeString(dnsSRVReply)
112	if err != nil {
113		t.Fatal(err)
114	}
115	msg := new(dnsMsg)
116	ok := msg.Unpack(data)
117	if !ok {
118		t.Fatal("unpacking packet failed")
119	}
120	_ = msg.String() // exercise this code path
121	if g, e := len(msg.answer), 5; g != e {
122		t.Errorf("len(msg.answer) = %d; want %d", g, e)
123	}
124	for idx, rr := range msg.answer {
125		if g, e := rr.Header().Rrtype, uint16(dnsTypeSRV); g != e {
126			t.Errorf("rr[%d].Header().Rrtype = %d; want %d", idx, g, e)
127		}
128		if _, ok := rr.(*dnsRR_SRV); !ok {
129			t.Errorf("answer[%d] = %T; want *dnsRR_SRV", idx, rr)
130		}
131	}
132	for _, name := range [...]string{
133		"_xmpp-server._tcp.google.com.",
134		"_XMPP-Server._TCP.Google.COM.",
135		"_XMPP-SERVER._TCP.GOOGLE.COM.",
136	} {
137		_, addrs, err := answer(name, "foo:53", msg, uint16(dnsTypeSRV))
138		if err != nil {
139			t.Error(err)
140		}
141		if g, e := len(addrs), 5; g != e {
142			t.Errorf("len(addrs) = %d; want %d", g, e)
143			t.Logf("addrs = %#v", addrs)
144		}
145	}
146	// repack and unpack.
147	data2, ok := msg.Pack()
148	msg2 := new(dnsMsg)
149	msg2.Unpack(data2)
150	switch {
151	case !ok:
152		t.Error("failed to repack message")
153	case !reflect.DeepEqual(msg, msg2):
154		t.Error("repacked message differs from original")
155	}
156}
157
158func TestDNSParseCorruptSRVReply(t *testing.T) {
159	data, err := hex.DecodeString(dnsSRVCorruptReply)
160	if err != nil {
161		t.Fatal(err)
162	}
163	msg := new(dnsMsg)
164	ok := msg.Unpack(data)
165	if !ok {
166		t.Fatal("unpacking packet failed")
167	}
168	_ = msg.String() // exercise this code path
169	if g, e := len(msg.answer), 5; g != e {
170		t.Errorf("len(msg.answer) = %d; want %d", g, e)
171	}
172	for idx, rr := range msg.answer {
173		if g, e := rr.Header().Rrtype, uint16(dnsTypeSRV); g != e {
174			t.Errorf("rr[%d].Header().Rrtype = %d; want %d", idx, g, e)
175		}
176		if idx == 4 {
177			if _, ok := rr.(*dnsRR_Header); !ok {
178				t.Errorf("answer[%d] = %T; want *dnsRR_Header", idx, rr)
179			}
180		} else {
181			if _, ok := rr.(*dnsRR_SRV); !ok {
182				t.Errorf("answer[%d] = %T; want *dnsRR_SRV", idx, rr)
183			}
184		}
185	}
186	_, addrs, err := answer("_xmpp-server._tcp.google.com.", "foo:53", msg, uint16(dnsTypeSRV))
187	if err != nil {
188		t.Fatalf("answer: %v", err)
189	}
190	if g, e := len(addrs), 4; g != e {
191		t.Errorf("len(addrs) = %d; want %d", g, e)
192		t.Logf("addrs = %#v", addrs)
193	}
194}
195
196func TestDNSParseTXTReply(t *testing.T) {
197	expectedTxt1 := "v=spf1 redirect=_spf.google.com"
198	expectedTxt2 := "v=spf1 ip4:69.63.179.25 ip4:69.63.178.128/25 ip4:69.63.184.0/25 " +
199		"ip4:66.220.144.128/25 ip4:66.220.155.0/24 " +
200		"ip4:69.171.232.0/25 ip4:66.220.157.0/25 " +
201		"ip4:69.171.244.0/24 mx -all"
202
203	replies := []string{dnsTXTReply1, dnsTXTReply2}
204	expectedTxts := []string{expectedTxt1, expectedTxt2}
205
206	for i := range replies {
207		data, err := hex.DecodeString(replies[i])
208		if err != nil {
209			t.Fatal(err)
210		}
211
212		msg := new(dnsMsg)
213		ok := msg.Unpack(data)
214		if !ok {
215			t.Errorf("test %d: unpacking packet failed", i)
216			continue
217		}
218
219		if len(msg.answer) != 1 {
220			t.Errorf("test %d: len(rr.answer) = %d; want 1", i, len(msg.answer))
221			continue
222		}
223
224		rr := msg.answer[0]
225		rrTXT, ok := rr.(*dnsRR_TXT)
226		if !ok {
227			t.Errorf("test %d: answer[0] = %T; want *dnsRR_TXT", i, rr)
228			continue
229		}
230
231		if rrTXT.Txt != expectedTxts[i] {
232			t.Errorf("test %d: Txt = %s; want %s", i, rrTXT.Txt, expectedTxts[i])
233		}
234	}
235}
236
237func TestDNSParseTXTCorruptDataLengthReply(t *testing.T) {
238	replies := []string{dnsTXTCorruptDataLengthReply1, dnsTXTCorruptDataLengthReply2}
239
240	for i := range replies {
241		data, err := hex.DecodeString(replies[i])
242		if err != nil {
243			t.Fatal(err)
244		}
245
246		msg := new(dnsMsg)
247		ok := msg.Unpack(data)
248		if ok {
249			t.Errorf("test %d: expected to fail on unpacking corrupt packet", i)
250		}
251	}
252}
253
254func TestDNSParseTXTCorruptTXTLengthReply(t *testing.T) {
255	replies := []string{dnsTXTCorruptTXTLengthReply1, dnsTXTCorruptTXTLengthReply2}
256
257	for i := range replies {
258		data, err := hex.DecodeString(replies[i])
259		if err != nil {
260			t.Fatal(err)
261		}
262
263		msg := new(dnsMsg)
264		ok := msg.Unpack(data)
265		// Unpacking should succeed, but we should just get the header.
266		if !ok {
267			t.Errorf("test %d: unpacking packet failed", i)
268			continue
269		}
270
271		if len(msg.answer) != 1 {
272			t.Errorf("test %d: len(rr.answer) = %d; want 1", i, len(msg.answer))
273			continue
274		}
275
276		rr := msg.answer[0]
277		if _, justHeader := rr.(*dnsRR_Header); !justHeader {
278			t.Errorf("test %d: rr = %T; expected *dnsRR_Header", i, rr)
279		}
280	}
281}
282
283func TestIsResponseTo(t *testing.T) {
284	// Sample DNS query.
285	query := dnsMsg{
286		dnsMsgHdr: dnsMsgHdr{
287			id: 42,
288		},
289		question: []dnsQuestion{
290			{
291				Name:   "www.example.com.",
292				Qtype:  dnsTypeA,
293				Qclass: dnsClassINET,
294			},
295		},
296	}
297
298	resp := query
299	resp.response = true
300	if !resp.IsResponseTo(&query) {
301		t.Error("got false, want true")
302	}
303
304	badResponses := []dnsMsg{
305		// Different ID.
306		{
307			dnsMsgHdr: dnsMsgHdr{
308				id:       43,
309				response: true,
310			},
311			question: []dnsQuestion{
312				{
313					Name:   "www.example.com.",
314					Qtype:  dnsTypeA,
315					Qclass: dnsClassINET,
316				},
317			},
318		},
319
320		// Different query name.
321		{
322			dnsMsgHdr: dnsMsgHdr{
323				id:       42,
324				response: true,
325			},
326			question: []dnsQuestion{
327				{
328					Name:   "www.google.com.",
329					Qtype:  dnsTypeA,
330					Qclass: dnsClassINET,
331				},
332			},
333		},
334
335		// Different query type.
336		{
337			dnsMsgHdr: dnsMsgHdr{
338				id:       42,
339				response: true,
340			},
341			question: []dnsQuestion{
342				{
343					Name:   "www.example.com.",
344					Qtype:  dnsTypeAAAA,
345					Qclass: dnsClassINET,
346				},
347			},
348		},
349
350		// Different query class.
351		{
352			dnsMsgHdr: dnsMsgHdr{
353				id:       42,
354				response: true,
355			},
356			question: []dnsQuestion{
357				{
358					Name:   "www.example.com.",
359					Qtype:  dnsTypeA,
360					Qclass: dnsClassCSNET,
361				},
362			},
363		},
364
365		// No questions.
366		{
367			dnsMsgHdr: dnsMsgHdr{
368				id:       42,
369				response: true,
370			},
371		},
372
373		// Extra questions.
374		{
375			dnsMsgHdr: dnsMsgHdr{
376				id:       42,
377				response: true,
378			},
379			question: []dnsQuestion{
380				{
381					Name:   "www.example.com.",
382					Qtype:  dnsTypeA,
383					Qclass: dnsClassINET,
384				},
385				{
386					Name:   "www.golang.org.",
387					Qtype:  dnsTypeAAAA,
388					Qclass: dnsClassINET,
389				},
390			},
391		},
392	}
393
394	for i := range badResponses {
395		if badResponses[i].IsResponseTo(&query) {
396			t.Errorf("%v: got true, want false", i)
397		}
398	}
399}
400
401// Valid DNS SRV reply
402const dnsSRVReply = "0901818000010005000000000c5f786d70702d736572766572045f74637006676f6f67" +
403	"6c6503636f6d0000210001c00c002100010000012c00210014000014950c786d70702d" +
404	"73657276657234016c06676f6f676c6503636f6d00c00c002100010000012c00210014" +
405	"000014950c786d70702d73657276657232016c06676f6f676c6503636f6d00c00c0021" +
406	"00010000012c00210014000014950c786d70702d73657276657233016c06676f6f676c" +
407	"6503636f6d00c00c002100010000012c00200005000014950b786d70702d7365727665" +
408	"72016c06676f6f676c6503636f6d00c00c002100010000012c00210014000014950c78" +
409	"6d70702d73657276657231016c06676f6f676c6503636f6d00"
410
411// Corrupt DNS SRV reply, with its final RR having a bogus length
412// (perhaps it was truncated, or it's malicious) The mutation is the
413// capital "FF" below, instead of the proper "21".
414const dnsSRVCorruptReply = "0901818000010005000000000c5f786d70702d736572766572045f74637006676f6f67" +
415	"6c6503636f6d0000210001c00c002100010000012c00210014000014950c786d70702d" +
416	"73657276657234016c06676f6f676c6503636f6d00c00c002100010000012c00210014" +
417	"000014950c786d70702d73657276657232016c06676f6f676c6503636f6d00c00c0021" +
418	"00010000012c00210014000014950c786d70702d73657276657233016c06676f6f676c" +
419	"6503636f6d00c00c002100010000012c00200005000014950b786d70702d7365727665" +
420	"72016c06676f6f676c6503636f6d00c00c002100010000012c00FF0014000014950c78" +
421	"6d70702d73657276657231016c06676f6f676c6503636f6d00"
422
423// TXT reply with one <character-string>
424const dnsTXTReply1 = "b3458180000100010004000505676d61696c03636f6d0000100001c00c001000010000012c00" +
425	"201f763d737066312072656469726563743d5f7370662e676f6f676c652e636f6dc00" +
426	"c0002000100025d4c000d036e733406676f6f676c65c012c00c0002000100025d4c00" +
427	"06036e7331c057c00c0002000100025d4c0006036e7333c057c00c0002000100025d4" +
428	"c0006036e7332c057c06c00010001000248b50004d8ef200ac09000010001000248b5" +
429	"0004d8ef220ac07e00010001000248b50004d8ef240ac05300010001000248b50004d" +
430	"8ef260a0000291000000000000000"
431
432// TXT reply with more than one <character-string>.
433// See https://tools.ietf.org/html/rfc1035#section-3.3.14
434const dnsTXTReply2 = "a0a381800001000100020002045f7370660866616365626f6f6b03636f6d0000100001c00c0010000" +
435	"100000e1000af7f763d73706631206970343a36392e36332e3137392e3235206970343a36392e" +
436	"36332e3137382e3132382f3235206970343a36392e36332e3138342e302f3235206970343a363" +
437	"62e3232302e3134342e3132382f3235206970343a36362e3232302e3135352e302f3234206970" +
438	"343a36392e3137312e3233322e302f323520692e70343a36362e3232302e3135372e302f32352" +
439	"06970343a36392e3137312e3234342e302f3234206d78202d616c6cc0110002000100025d1500" +
440	"070161026e73c011c0110002000100025d1500040162c0ecc0ea0001000100025d15000445abe" +
441	"f0cc0fd0001000100025d15000445abff0c"
442
443// DataLength field should be sum of all TXT fields. In this case it's less.
444const dnsTXTCorruptDataLengthReply1 = "a0a381800001000100020002045f7370660866616365626f6f6b03636f6d0000100001c00c0010000" +
445	"100000e1000967f763d73706631206970343a36392e36332e3137392e3235206970343a36392e" +
446	"36332e3137382e3132382f3235206970343a36392e36332e3138342e302f3235206970343a363" +
447	"62e3232302e3134342e3132382f3235206970343a36362e3232302e3135352e302f3234206970" +
448	"343a36392e3137312e3233322e302f323520692e70343a36362e3232302e3135372e302f32352" +
449	"06970343a36392e3137312e3234342e302f3234206d78202d616c6cc0110002000100025d1500" +
450	"070161026e73c011c0110002000100025d1500040162c0ecc0ea0001000100025d15000445abe" +
451	"f0cc0fd0001000100025d15000445abff0c"
452
453// Same as above but DataLength is more than sum of TXT fields.
454const dnsTXTCorruptDataLengthReply2 = "a0a381800001000100020002045f7370660866616365626f6f6b03636f6d0000100001c00c0010000" +
455	"100000e1001227f763d73706631206970343a36392e36332e3137392e3235206970343a36392e" +
456	"36332e3137382e3132382f3235206970343a36392e36332e3138342e302f3235206970343a363" +
457	"62e3232302e3134342e3132382f3235206970343a36362e3232302e3135352e302f3234206970" +
458	"343a36392e3137312e3233322e302f323520692e70343a36362e3232302e3135372e302f32352" +
459	"06970343a36392e3137312e3234342e302f3234206d78202d616c6cc0110002000100025d1500" +
460	"070161026e73c011c0110002000100025d1500040162c0ecc0ea0001000100025d15000445abe" +
461	"f0cc0fd0001000100025d15000445abff0c"
462
463// TXT Length field is less than actual length.
464const dnsTXTCorruptTXTLengthReply1 = "a0a381800001000100020002045f7370660866616365626f6f6b03636f6d0000100001c00c0010000" +
465	"100000e1000af7f763d73706631206970343a36392e36332e3137392e3235206970343a36392e" +
466	"36332e3137382e3132382f3235206970343a36392e36332e3138342e302f3235206970343a363" +
467	"62e3232302e3134342e3132382f3235206970343a36362e3232302e3135352e302f3234206970" +
468	"343a36392e3137312e3233322e302f323520691470343a36362e3232302e3135372e302f32352" +
469	"06970343a36392e3137312e3234342e302f3234206d78202d616c6cc0110002000100025d1500" +
470	"070161026e73c011c0110002000100025d1500040162c0ecc0ea0001000100025d15000445abe" +
471	"f0cc0fd0001000100025d15000445abff0c"
472
473// TXT Length field is more than actual length.
474const dnsTXTCorruptTXTLengthReply2 = "a0a381800001000100020002045f7370660866616365626f6f6b03636f6d0000100001c00c0010000" +
475	"100000e1000af7f763d73706631206970343a36392e36332e3137392e3235206970343a36392e" +
476	"36332e3137382e3132382f3235206970343a36392e36332e3138342e302f3235206970343a363" +
477	"62e3232302e3134342e3132382f3235206970343a36362e3232302e3135352e302f3234206970" +
478	"343a36392e3137312e3233322e302f323520693370343a36362e3232302e3135372e302f32352" +
479	"06970343a36392e3137312e3234342e302f3234206d78202d616c6cc0110002000100025d1500" +
480	"070161026e73c011c0110002000100025d1500040162c0ecc0ea0001000100025d15000445abe" +
481	"f0cc0fd0001000100025d15000445abff0c"
482