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Source file src/net/dnsmsg_test.go

Documentation: net

  // Copyright 2011 The Go Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  package net
  
  import (
  	"encoding/hex"
  	"reflect"
  	"testing"
  )
  
  func TestStructPackUnpack(t *testing.T) {
  	want := dnsQuestion{
  		Name:   ".",
  		Qtype:  dnsTypeA,
  		Qclass: dnsClassINET,
  	}
  	buf := make([]byte, 50)
  	n, ok := packStruct(&want, buf, 0)
  	if !ok {
  		t.Fatal("packing failed")
  	}
  	buf = buf[:n]
  	got := dnsQuestion{}
  	n, ok = unpackStruct(&got, buf, 0)
  	if !ok {
  		t.Fatal("unpacking failed")
  	}
  	if n != len(buf) {
  		t.Errorf("unpacked different amount than packed: got n = %d, want = %d", n, len(buf))
  	}
  	if !reflect.DeepEqual(got, want) {
  		t.Errorf("got = %+v, want = %+v", got, want)
  	}
  }
  
  func TestDomainNamePackUnpack(t *testing.T) {
  	tests := []struct {
  		in   string
  		want string
  		ok   bool
  	}{
  		{"", ".", true},
  		{".", ".", true},
  		{"google..com", "", false},
  		{"google.com", "google.com.", true},
  		{"google..com.", "", false},
  		{"google.com.", "google.com.", true},
  		{".google.com.", "", false},
  		{"www..google.com.", "", false},
  		{"www.google.com.", "www.google.com.", true},
  	}
  
  	for _, test := range tests {
  		buf := make([]byte, 30)
  		n, ok := packDomainName(test.in, buf, 0)
  		if ok != test.ok {
  			t.Errorf("packing of %s: got ok = %t, want = %t", test.in, ok, test.ok)
  			continue
  		}
  		if !test.ok {
  			continue
  		}
  		buf = buf[:n]
  		got, n, ok := unpackDomainName(buf, 0)
  		if !ok {
  			t.Errorf("unpacking for %s failed", test.in)
  			continue
  		}
  		if n != len(buf) {
  			t.Errorf(
  				"unpacked different amount than packed for %s: got n = %d, want = %d",
  				test.in,
  				n,
  				len(buf),
  			)
  		}
  		if got != test.want {
  			t.Errorf("unpacking packing of %s: got = %s, want = %s", test.in, got, test.want)
  		}
  	}
  }
  
  func TestDNSPackUnpack(t *testing.T) {
  	want := dnsMsg{
  		question: []dnsQuestion{{
  			Name:   ".",
  			Qtype:  dnsTypeAAAA,
  			Qclass: dnsClassINET,
  		}},
  		answer: []dnsRR{},
  		ns:     []dnsRR{},
  		extra:  []dnsRR{},
  	}
  	b, ok := want.Pack()
  	if !ok {
  		t.Fatal("packing failed")
  	}
  	var got dnsMsg
  	ok = got.Unpack(b)
  	if !ok {
  		t.Fatal("unpacking failed")
  	}
  	if !reflect.DeepEqual(got, want) {
  		t.Errorf("got = %+v, want = %+v", got, want)
  	}
  }
  
  func TestDNSParseSRVReply(t *testing.T) {
  	data, err := hex.DecodeString(dnsSRVReply)
  	if err != nil {
  		t.Fatal(err)
  	}
  	msg := new(dnsMsg)
  	ok := msg.Unpack(data)
  	if !ok {
  		t.Fatal("unpacking packet failed")
  	}
  	_ = msg.String() // exercise this code path
  	if g, e := len(msg.answer), 5; g != e {
  		t.Errorf("len(msg.answer) = %d; want %d", g, e)
  	}
  	for idx, rr := range msg.answer {
  		if g, e := rr.Header().Rrtype, uint16(dnsTypeSRV); g != e {
  			t.Errorf("rr[%d].Header().Rrtype = %d; want %d", idx, g, e)
  		}
  		if _, ok := rr.(*dnsRR_SRV); !ok {
  			t.Errorf("answer[%d] = %T; want *dnsRR_SRV", idx, rr)
  		}
  	}
  	for _, name := range [...]string{
  		"_xmpp-server._tcp.google.com.",
  		"_XMPP-Server._TCP.Google.COM.",
  		"_XMPP-SERVER._TCP.GOOGLE.COM.",
  	} {
  		_, addrs, err := answer(name, "foo:53", msg, uint16(dnsTypeSRV))
  		if err != nil {
  			t.Error(err)
  		}
  		if g, e := len(addrs), 5; g != e {
  			t.Errorf("len(addrs) = %d; want %d", g, e)
  			t.Logf("addrs = %#v", addrs)
  		}
  	}
  	// repack and unpack.
  	data2, ok := msg.Pack()
  	msg2 := new(dnsMsg)
  	msg2.Unpack(data2)
  	switch {
  	case !ok:
  		t.Error("failed to repack message")
  	case !reflect.DeepEqual(msg, msg2):
  		t.Error("repacked message differs from original")
  	}
  }
  
  func TestDNSParseCorruptSRVReply(t *testing.T) {
  	data, err := hex.DecodeString(dnsSRVCorruptReply)
  	if err != nil {
  		t.Fatal(err)
  	}
  	msg := new(dnsMsg)
  	ok := msg.Unpack(data)
  	if !ok {
  		t.Fatal("unpacking packet failed")
  	}
  	_ = msg.String() // exercise this code path
  	if g, e := len(msg.answer), 5; g != e {
  		t.Errorf("len(msg.answer) = %d; want %d", g, e)
  	}
  	for idx, rr := range msg.answer {
  		if g, e := rr.Header().Rrtype, uint16(dnsTypeSRV); g != e {
  			t.Errorf("rr[%d].Header().Rrtype = %d; want %d", idx, g, e)
  		}
  		if idx == 4 {
  			if _, ok := rr.(*dnsRR_Header); !ok {
  				t.Errorf("answer[%d] = %T; want *dnsRR_Header", idx, rr)
  			}
  		} else {
  			if _, ok := rr.(*dnsRR_SRV); !ok {
  				t.Errorf("answer[%d] = %T; want *dnsRR_SRV", idx, rr)
  			}
  		}
  	}
  	_, addrs, err := answer("_xmpp-server._tcp.google.com.", "foo:53", msg, uint16(dnsTypeSRV))
  	if err != nil {
  		t.Fatalf("answer: %v", err)
  	}
  	if g, e := len(addrs), 4; g != e {
  		t.Errorf("len(addrs) = %d; want %d", g, e)
  		t.Logf("addrs = %#v", addrs)
  	}
  }
  
  func TestDNSParseTXTReply(t *testing.T) {
  	expectedTxt1 := "v=spf1 redirect=_spf.google.com"
  	expectedTxt2 := "v=spf1 ip4:69.63.179.25 ip4:69.63.178.128/25 ip4:69.63.184.0/25 " +
  		"ip4:66.220.144.128/25 ip4:66.220.155.0/24 " +
  		"ip4:69.171.232.0/25 ip4:66.220.157.0/25 " +
  		"ip4:69.171.244.0/24 mx -all"
  
  	replies := []string{dnsTXTReply1, dnsTXTReply2}
  	expectedTxts := []string{expectedTxt1, expectedTxt2}
  
  	for i := range replies {
  		data, err := hex.DecodeString(replies[i])
  		if err != nil {
  			t.Fatal(err)
  		}
  
  		msg := new(dnsMsg)
  		ok := msg.Unpack(data)
  		if !ok {
  			t.Errorf("test %d: unpacking packet failed", i)
  			continue
  		}
  
  		if len(msg.answer) != 1 {
  			t.Errorf("test %d: len(rr.answer) = %d; want 1", i, len(msg.answer))
  			continue
  		}
  
  		rr := msg.answer[0]
  		rrTXT, ok := rr.(*dnsRR_TXT)
  		if !ok {
  			t.Errorf("test %d: answer[0] = %T; want *dnsRR_TXT", i, rr)
  			continue
  		}
  
  		if rrTXT.Txt != expectedTxts[i] {
  			t.Errorf("test %d: Txt = %s; want %s", i, rrTXT.Txt, expectedTxts[i])
  		}
  	}
  }
  
  func TestDNSParseTXTCorruptDataLengthReply(t *testing.T) {
  	replies := []string{dnsTXTCorruptDataLengthReply1, dnsTXTCorruptDataLengthReply2}
  
  	for i := range replies {
  		data, err := hex.DecodeString(replies[i])
  		if err != nil {
  			t.Fatal(err)
  		}
  
  		msg := new(dnsMsg)
  		ok := msg.Unpack(data)
  		if ok {
  			t.Errorf("test %d: expected to fail on unpacking corrupt packet", i)
  		}
  	}
  }
  
  func TestDNSParseTXTCorruptTXTLengthReply(t *testing.T) {
  	replies := []string{dnsTXTCorruptTXTLengthReply1, dnsTXTCorruptTXTLengthReply2}
  
  	for i := range replies {
  		data, err := hex.DecodeString(replies[i])
  		if err != nil {
  			t.Fatal(err)
  		}
  
  		msg := new(dnsMsg)
  		ok := msg.Unpack(data)
  		// Unpacking should succeed, but we should just get the header.
  		if !ok {
  			t.Errorf("test %d: unpacking packet failed", i)
  			continue
  		}
  
  		if len(msg.answer) != 1 {
  			t.Errorf("test %d: len(rr.answer) = %d; want 1", i, len(msg.answer))
  			continue
  		}
  
  		rr := msg.answer[0]
  		if _, justHeader := rr.(*dnsRR_Header); !justHeader {
  			t.Errorf("test %d: rr = %T; expected *dnsRR_Header", i, rr)
  		}
  	}
  }
  
  func TestIsResponseTo(t *testing.T) {
  	// Sample DNS query.
  	query := dnsMsg{
  		dnsMsgHdr: dnsMsgHdr{
  			id: 42,
  		},
  		question: []dnsQuestion{
  			{
  				Name:   "www.example.com.",
  				Qtype:  dnsTypeA,
  				Qclass: dnsClassINET,
  			},
  		},
  	}
  
  	resp := query
  	resp.response = true
  	if !resp.IsResponseTo(&query) {
  		t.Error("got false, want true")
  	}
  
  	badResponses := []dnsMsg{
  		// Different ID.
  		{
  			dnsMsgHdr: dnsMsgHdr{
  				id:       43,
  				response: true,
  			},
  			question: []dnsQuestion{
  				{
  					Name:   "www.example.com.",
  					Qtype:  dnsTypeA,
  					Qclass: dnsClassINET,
  				},
  			},
  		},
  
  		// Different query name.
  		{
  			dnsMsgHdr: dnsMsgHdr{
  				id:       42,
  				response: true,
  			},
  			question: []dnsQuestion{
  				{
  					Name:   "www.google.com.",
  					Qtype:  dnsTypeA,
  					Qclass: dnsClassINET,
  				},
  			},
  		},
  
  		// Different query type.
  		{
  			dnsMsgHdr: dnsMsgHdr{
  				id:       42,
  				response: true,
  			},
  			question: []dnsQuestion{
  				{
  					Name:   "www.example.com.",
  					Qtype:  dnsTypeAAAA,
  					Qclass: dnsClassINET,
  				},
  			},
  		},
  
  		// Different query class.
  		{
  			dnsMsgHdr: dnsMsgHdr{
  				id:       42,
  				response: true,
  			},
  			question: []dnsQuestion{
  				{
  					Name:   "www.example.com.",
  					Qtype:  dnsTypeA,
  					Qclass: dnsClassCSNET,
  				},
  			},
  		},
  
  		// No questions.
  		{
  			dnsMsgHdr: dnsMsgHdr{
  				id:       42,
  				response: true,
  			},
  		},
  
  		// Extra questions.
  		{
  			dnsMsgHdr: dnsMsgHdr{
  				id:       42,
  				response: true,
  			},
  			question: []dnsQuestion{
  				{
  					Name:   "www.example.com.",
  					Qtype:  dnsTypeA,
  					Qclass: dnsClassINET,
  				},
  				{
  					Name:   "www.golang.org.",
  					Qtype:  dnsTypeAAAA,
  					Qclass: dnsClassINET,
  				},
  			},
  		},
  	}
  
  	for i := range badResponses {
  		if badResponses[i].IsResponseTo(&query) {
  			t.Errorf("%v: got true, want false", i)
  		}
  	}
  }
  
  // Valid DNS SRV reply
  const dnsSRVReply = "0901818000010005000000000c5f786d70702d736572766572045f74637006676f6f67" +
  	"6c6503636f6d0000210001c00c002100010000012c00210014000014950c786d70702d" +
  	"73657276657234016c06676f6f676c6503636f6d00c00c002100010000012c00210014" +
  	"000014950c786d70702d73657276657232016c06676f6f676c6503636f6d00c00c0021" +
  	"00010000012c00210014000014950c786d70702d73657276657233016c06676f6f676c" +
  	"6503636f6d00c00c002100010000012c00200005000014950b786d70702d7365727665" +
  	"72016c06676f6f676c6503636f6d00c00c002100010000012c00210014000014950c78" +
  	"6d70702d73657276657231016c06676f6f676c6503636f6d00"
  
  // Corrupt DNS SRV reply, with its final RR having a bogus length
  // (perhaps it was truncated, or it's malicious) The mutation is the
  // capital "FF" below, instead of the proper "21".
  const dnsSRVCorruptReply = "0901818000010005000000000c5f786d70702d736572766572045f74637006676f6f67" +
  	"6c6503636f6d0000210001c00c002100010000012c00210014000014950c786d70702d" +
  	"73657276657234016c06676f6f676c6503636f6d00c00c002100010000012c00210014" +
  	"000014950c786d70702d73657276657232016c06676f6f676c6503636f6d00c00c0021" +
  	"00010000012c00210014000014950c786d70702d73657276657233016c06676f6f676c" +
  	"6503636f6d00c00c002100010000012c00200005000014950b786d70702d7365727665" +
  	"72016c06676f6f676c6503636f6d00c00c002100010000012c00FF0014000014950c78" +
  	"6d70702d73657276657231016c06676f6f676c6503636f6d00"
  
  // TXT reply with one <character-string>
  const dnsTXTReply1 = "b3458180000100010004000505676d61696c03636f6d0000100001c00c001000010000012c00" +
  	"201f763d737066312072656469726563743d5f7370662e676f6f676c652e636f6dc00" +
  	"c0002000100025d4c000d036e733406676f6f676c65c012c00c0002000100025d4c00" +
  	"06036e7331c057c00c0002000100025d4c0006036e7333c057c00c0002000100025d4" +
  	"c0006036e7332c057c06c00010001000248b50004d8ef200ac09000010001000248b5" +
  	"0004d8ef220ac07e00010001000248b50004d8ef240ac05300010001000248b50004d" +
  	"8ef260a0000291000000000000000"
  
  // TXT reply with more than one <character-string>.
  // See https://tools.ietf.org/html/rfc1035#section-3.3.14
  const dnsTXTReply2 = "a0a381800001000100020002045f7370660866616365626f6f6b03636f6d0000100001c00c0010000" +
  	"100000e1000af7f763d73706631206970343a36392e36332e3137392e3235206970343a36392e" +
  	"36332e3137382e3132382f3235206970343a36392e36332e3138342e302f3235206970343a363" +
  	"62e3232302e3134342e3132382f3235206970343a36362e3232302e3135352e302f3234206970" +
  	"343a36392e3137312e3233322e302f323520692e70343a36362e3232302e3135372e302f32352" +
  	"06970343a36392e3137312e3234342e302f3234206d78202d616c6cc0110002000100025d1500" +
  	"070161026e73c011c0110002000100025d1500040162c0ecc0ea0001000100025d15000445abe" +
  	"f0cc0fd0001000100025d15000445abff0c"
  
  // DataLength field should be sum of all TXT fields. In this case it's less.
  const dnsTXTCorruptDataLengthReply1 = "a0a381800001000100020002045f7370660866616365626f6f6b03636f6d0000100001c00c0010000" +
  	"100000e1000967f763d73706631206970343a36392e36332e3137392e3235206970343a36392e" +
  	"36332e3137382e3132382f3235206970343a36392e36332e3138342e302f3235206970343a363" +
  	"62e3232302e3134342e3132382f3235206970343a36362e3232302e3135352e302f3234206970" +
  	"343a36392e3137312e3233322e302f323520692e70343a36362e3232302e3135372e302f32352" +
  	"06970343a36392e3137312e3234342e302f3234206d78202d616c6cc0110002000100025d1500" +
  	"070161026e73c011c0110002000100025d1500040162c0ecc0ea0001000100025d15000445abe" +
  	"f0cc0fd0001000100025d15000445abff0c"
  
  // Same as above but DataLength is more than sum of TXT fields.
  const dnsTXTCorruptDataLengthReply2 = "a0a381800001000100020002045f7370660866616365626f6f6b03636f6d0000100001c00c0010000" +
  	"100000e1001227f763d73706631206970343a36392e36332e3137392e3235206970343a36392e" +
  	"36332e3137382e3132382f3235206970343a36392e36332e3138342e302f3235206970343a363" +
  	"62e3232302e3134342e3132382f3235206970343a36362e3232302e3135352e302f3234206970" +
  	"343a36392e3137312e3233322e302f323520692e70343a36362e3232302e3135372e302f32352" +
  	"06970343a36392e3137312e3234342e302f3234206d78202d616c6cc0110002000100025d1500" +
  	"070161026e73c011c0110002000100025d1500040162c0ecc0ea0001000100025d15000445abe" +
  	"f0cc0fd0001000100025d15000445abff0c"
  
  // TXT Length field is less than actual length.
  const dnsTXTCorruptTXTLengthReply1 = "a0a381800001000100020002045f7370660866616365626f6f6b03636f6d0000100001c00c0010000" +
  	"100000e1000af7f763d73706631206970343a36392e36332e3137392e3235206970343a36392e" +
  	"36332e3137382e3132382f3235206970343a36392e36332e3138342e302f3235206970343a363" +
  	"62e3232302e3134342e3132382f3235206970343a36362e3232302e3135352e302f3234206970" +
  	"343a36392e3137312e3233322e302f323520691470343a36362e3232302e3135372e302f32352" +
  	"06970343a36392e3137312e3234342e302f3234206d78202d616c6cc0110002000100025d1500" +
  	"070161026e73c011c0110002000100025d1500040162c0ecc0ea0001000100025d15000445abe" +
  	"f0cc0fd0001000100025d15000445abff0c"
  
  // TXT Length field is more than actual length.
  const dnsTXTCorruptTXTLengthReply2 = "a0a381800001000100020002045f7370660866616365626f6f6b03636f6d0000100001c00c0010000" +
  	"100000e1000af7f763d73706631206970343a36392e36332e3137392e3235206970343a36392e" +
  	"36332e3137382e3132382f3235206970343a36392e36332e3138342e302f3235206970343a363" +
  	"62e3232302e3134342e3132382f3235206970343a36362e3232302e3135352e302f3234206970" +
  	"343a36392e3137312e3233322e302f323520693370343a36362e3232302e3135372e302f32352" +
  	"06970343a36392e3137312e3234342e302f3234206d78202d616c6cc0110002000100025d1500" +
  	"070161026e73c011c0110002000100025d1500040162c0ecc0ea0001000100025d15000445abe" +
  	"f0cc0fd0001000100025d15000445abff0c"
  

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