7c45f7b88c
Previously, the DNS decoder did not check whether it was parsing
a DNS query or a DNS response, which was wrong.
As a side note, it seems I am using "reply" in the codebase instead
of "response". The latter seems correct DNS terminology.
This diff has been extracted from 9249d14f80
See https://github.com/ooni/probe/issues/2096.
500 lines
14 KiB
Go
500 lines
14 KiB
Go
package netxlite
|
|
|
|
import (
|
|
"errors"
|
|
"net"
|
|
"strings"
|
|
"testing"
|
|
|
|
"github.com/google/go-cmp/cmp"
|
|
"github.com/miekg/dns"
|
|
"github.com/ooni/probe-cli/v3/internal/runtimex"
|
|
)
|
|
|
|
func TestDNSDecoder(t *testing.T) {
|
|
t.Run("LookupHost", func(t *testing.T) {
|
|
t.Run("UnpackError", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
data, err := d.DecodeLookupHost(dns.TypeA, nil, 0)
|
|
if err == nil || err.Error() != "dns: overflow unpacking uint16" {
|
|
t.Fatal("unexpected error", err)
|
|
}
|
|
if data != nil {
|
|
t.Fatal("expected nil data here")
|
|
}
|
|
})
|
|
|
|
t.Run("with bytes containing a query", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
queryID := dns.Id()
|
|
rawQuery := dnsGenQuery(dns.TypeA, queryID)
|
|
addrs, err := d.DecodeLookupHost(dns.TypeA, rawQuery, queryID)
|
|
if !errors.Is(err, ErrDNSIsQuery) {
|
|
t.Fatal("unexpected err", err)
|
|
}
|
|
if len(addrs) > 0 {
|
|
t.Fatal("expected no addrs")
|
|
}
|
|
})
|
|
|
|
t.Run("wrong query ID", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
const (
|
|
queryID = 17
|
|
unrelatedID = 14
|
|
)
|
|
reply := dnsGenLookupHostReplySuccess(dnsGenQuery(dns.TypeA, queryID))
|
|
data, err := d.DecodeLookupHost(dns.TypeA, reply, unrelatedID)
|
|
if !errors.Is(err, ErrDNSReplyWithWrongQueryID) {
|
|
t.Fatal("unexpected error", err)
|
|
}
|
|
if data != nil {
|
|
t.Fatal("expected nil data here")
|
|
}
|
|
})
|
|
|
|
t.Run("NXDOMAIN", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
queryID := dns.Id()
|
|
data, err := d.DecodeLookupHost(dns.TypeA, dnsGenReplyWithError(
|
|
dnsGenQuery(dns.TypeA, queryID), dns.RcodeNameError), queryID)
|
|
if err == nil || !strings.HasSuffix(err.Error(), "no such host") {
|
|
t.Fatal("not the error we expected", err)
|
|
}
|
|
if data != nil {
|
|
t.Fatal("expected nil data here")
|
|
}
|
|
})
|
|
|
|
t.Run("Refused", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
queryID := dns.Id()
|
|
data, err := d.DecodeLookupHost(dns.TypeA, dnsGenReplyWithError(
|
|
dnsGenQuery(dns.TypeA, queryID), dns.RcodeRefused), queryID)
|
|
if !errors.Is(err, ErrOODNSRefused) {
|
|
t.Fatal("not the error we expected", err)
|
|
}
|
|
if data != nil {
|
|
t.Fatal("expected nil data here")
|
|
}
|
|
})
|
|
|
|
t.Run("Servfail", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
queryID := dns.Id()
|
|
data, err := d.DecodeLookupHost(dns.TypeA, dnsGenReplyWithError(
|
|
dnsGenQuery(dns.TypeA, queryID), dns.RcodeServerFailure), queryID)
|
|
if !errors.Is(err, ErrOODNSServfail) {
|
|
t.Fatal("not the error we expected", err)
|
|
}
|
|
if data != nil {
|
|
t.Fatal("expected nil data here")
|
|
}
|
|
})
|
|
|
|
t.Run("no address", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
queryID := dns.Id()
|
|
data, err := d.DecodeLookupHost(dns.TypeA, dnsGenLookupHostReplySuccess(
|
|
dnsGenQuery(dns.TypeA, queryID)), queryID)
|
|
if !errors.Is(err, ErrOODNSNoAnswer) {
|
|
t.Fatal("not the error we expected", err)
|
|
}
|
|
if data != nil {
|
|
t.Fatal("expected nil data here")
|
|
}
|
|
})
|
|
|
|
t.Run("decode A", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
queryID := dns.Id()
|
|
data, err := d.DecodeLookupHost(dns.TypeA, dnsGenLookupHostReplySuccess(
|
|
dnsGenQuery(dns.TypeA, queryID), "1.1.1.1", "8.8.8.8"), queryID)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if len(data) != 2 {
|
|
t.Fatal("expected two entries here")
|
|
}
|
|
if data[0] != "1.1.1.1" {
|
|
t.Fatal("invalid first IPv4 entry")
|
|
}
|
|
if data[1] != "8.8.8.8" {
|
|
t.Fatal("invalid second IPv4 entry")
|
|
}
|
|
})
|
|
|
|
t.Run("decode AAAA", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
queryID := dns.Id()
|
|
data, err := d.DecodeLookupHost(dns.TypeAAAA, dnsGenLookupHostReplySuccess(
|
|
dnsGenQuery(dns.TypeAAAA, queryID), "::1", "fe80::1"), queryID)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if len(data) != 2 {
|
|
t.Fatal("expected two entries here")
|
|
}
|
|
if data[0] != "::1" {
|
|
t.Fatal("invalid first IPv6 entry")
|
|
}
|
|
if data[1] != "fe80::1" {
|
|
t.Fatal("invalid second IPv6 entry")
|
|
}
|
|
})
|
|
|
|
t.Run("unexpected A reply", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
queryID := dns.Id()
|
|
data, err := d.DecodeLookupHost(dns.TypeA, dnsGenLookupHostReplySuccess(
|
|
dnsGenQuery(dns.TypeAAAA, queryID), "::1", "fe80::1"), queryID)
|
|
if !errors.Is(err, ErrOODNSNoAnswer) {
|
|
t.Fatal("not the error we expected", err)
|
|
}
|
|
if data != nil {
|
|
t.Fatal("expected nil data here")
|
|
}
|
|
})
|
|
|
|
t.Run("unexpected AAAA reply", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
queryID := dns.Id()
|
|
data, err := d.DecodeLookupHost(dns.TypeAAAA, dnsGenLookupHostReplySuccess(
|
|
dnsGenQuery(dns.TypeA, queryID), "1.1.1.1", "8.8.4.4"), queryID)
|
|
if !errors.Is(err, ErrOODNSNoAnswer) {
|
|
t.Fatal("not the error we expected", err)
|
|
}
|
|
if data != nil {
|
|
t.Fatal("expected nil data here")
|
|
}
|
|
})
|
|
})
|
|
|
|
t.Run("decodeSuccessfulReply", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
msg := &dns.Msg{}
|
|
msg.Rcode = dns.RcodeFormatError // an rcode we don't handle
|
|
msg.Response = true
|
|
data, err := msg.Pack()
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
reply, err := d.decodeSuccessfulReply(data, 0)
|
|
if !errors.Is(err, ErrOODNSMisbehaving) { // catch all error
|
|
t.Fatal("not the error we expected", err)
|
|
}
|
|
if reply != nil {
|
|
t.Fatal("expected nil reply")
|
|
}
|
|
})
|
|
|
|
t.Run("DecodeHTTPS", func(t *testing.T) {
|
|
t.Run("with nil data", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
reply, err := d.DecodeHTTPS(nil, 0)
|
|
if err == nil || err.Error() != "dns: overflow unpacking uint16" {
|
|
t.Fatal("not the error we expected", err)
|
|
}
|
|
if reply != nil {
|
|
t.Fatal("expected nil reply")
|
|
}
|
|
})
|
|
|
|
t.Run("with bytes containing a query", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
queryID := dns.Id()
|
|
rawQuery := dnsGenQuery(dns.TypeHTTPS, queryID)
|
|
https, err := d.DecodeHTTPS(rawQuery, queryID)
|
|
if !errors.Is(err, ErrDNSIsQuery) {
|
|
t.Fatal("unexpected err", err)
|
|
}
|
|
if https != nil {
|
|
t.Fatal("expected nil https")
|
|
}
|
|
})
|
|
|
|
t.Run("wrong query ID", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
const (
|
|
queryID = 17
|
|
unrelatedID = 14
|
|
)
|
|
reply := dnsGenHTTPSReplySuccess(dnsGenQuery(dns.TypeHTTPS, queryID), nil, nil, nil)
|
|
data, err := d.DecodeHTTPS(reply, unrelatedID)
|
|
if !errors.Is(err, ErrDNSReplyWithWrongQueryID) {
|
|
t.Fatal("unexpected error", err)
|
|
}
|
|
if data != nil {
|
|
t.Fatal("expected nil data here")
|
|
}
|
|
})
|
|
|
|
t.Run("with empty answer", func(t *testing.T) {
|
|
queryID := dns.Id()
|
|
data := dnsGenHTTPSReplySuccess(
|
|
dnsGenQuery(dns.TypeHTTPS, queryID), nil, nil, nil)
|
|
d := &DNSDecoderMiekg{}
|
|
reply, err := d.DecodeHTTPS(data, queryID)
|
|
if !errors.Is(err, ErrOODNSNoAnswer) {
|
|
t.Fatal("unexpected err", err)
|
|
}
|
|
if reply != nil {
|
|
t.Fatal("expected nil reply")
|
|
}
|
|
})
|
|
|
|
t.Run("with full answer", func(t *testing.T) {
|
|
queryID := dns.Id()
|
|
alpn := []string{"h3"}
|
|
v4 := []string{"1.1.1.1"}
|
|
v6 := []string{"::1"}
|
|
data := dnsGenHTTPSReplySuccess(
|
|
dnsGenQuery(dns.TypeHTTPS, queryID), alpn, v4, v6)
|
|
d := &DNSDecoderMiekg{}
|
|
reply, err := d.DecodeHTTPS(data, queryID)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if diff := cmp.Diff(alpn, reply.ALPN); diff != "" {
|
|
t.Fatal(diff)
|
|
}
|
|
if diff := cmp.Diff(v4, reply.IPv4); diff != "" {
|
|
t.Fatal(diff)
|
|
}
|
|
if diff := cmp.Diff(v6, reply.IPv6); diff != "" {
|
|
t.Fatal(diff)
|
|
}
|
|
})
|
|
})
|
|
|
|
t.Run("DecodeNS", func(t *testing.T) {
|
|
t.Run("with nil data", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
reply, err := d.DecodeNS(nil, 0)
|
|
if err == nil || err.Error() != "dns: overflow unpacking uint16" {
|
|
t.Fatal("not the error we expected", err)
|
|
}
|
|
if reply != nil {
|
|
t.Fatal("expected nil reply")
|
|
}
|
|
})
|
|
|
|
t.Run("with bytes containing a query", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
queryID := dns.Id()
|
|
rawQuery := dnsGenQuery(dns.TypeNS, queryID)
|
|
ns, err := d.DecodeNS(rawQuery, queryID)
|
|
if !errors.Is(err, ErrDNSIsQuery) {
|
|
t.Fatal("unexpected err", err)
|
|
}
|
|
if len(ns) > 0 {
|
|
t.Fatal("expected no result")
|
|
}
|
|
})
|
|
|
|
t.Run("wrong query ID", func(t *testing.T) {
|
|
d := &DNSDecoderMiekg{}
|
|
const (
|
|
queryID = 17
|
|
unrelatedID = 14
|
|
)
|
|
reply := dnsGenNSReplySuccess(dnsGenQuery(dns.TypeNS, queryID))
|
|
data, err := d.DecodeNS(reply, unrelatedID)
|
|
if !errors.Is(err, ErrDNSReplyWithWrongQueryID) {
|
|
t.Fatal("unexpected error", err)
|
|
}
|
|
if data != nil {
|
|
t.Fatal("expected nil data here")
|
|
}
|
|
})
|
|
|
|
t.Run("with empty answer", func(t *testing.T) {
|
|
queryID := dns.Id()
|
|
data := dnsGenNSReplySuccess(dnsGenQuery(dns.TypeNS, queryID))
|
|
d := &DNSDecoderMiekg{}
|
|
reply, err := d.DecodeNS(data, queryID)
|
|
if !errors.Is(err, ErrOODNSNoAnswer) {
|
|
t.Fatal("unexpected err", err)
|
|
}
|
|
if reply != nil {
|
|
t.Fatal("expected nil reply")
|
|
}
|
|
})
|
|
|
|
t.Run("with full answer", func(t *testing.T) {
|
|
queryID := dns.Id()
|
|
data := dnsGenNSReplySuccess(dnsGenQuery(dns.TypeNS, queryID), "ns1.zdns.google.")
|
|
d := &DNSDecoderMiekg{}
|
|
reply, err := d.DecodeNS(data, queryID)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if len(reply) != 1 {
|
|
t.Fatal("unexpected reply length")
|
|
}
|
|
if reply[0].Host != "ns1.zdns.google." {
|
|
t.Fatal("unexpected reply host")
|
|
}
|
|
})
|
|
})
|
|
}
|
|
|
|
// dnsGenQuery generates a query suitable to be used with testing.
|
|
func dnsGenQuery(qtype uint16, queryID uint16) []byte {
|
|
question := dns.Question{
|
|
Name: dns.Fqdn("x.org"),
|
|
Qtype: qtype,
|
|
Qclass: dns.ClassINET,
|
|
}
|
|
query := new(dns.Msg)
|
|
query.Id = queryID
|
|
query.RecursionDesired = true
|
|
query.Question = make([]dns.Question, 1)
|
|
query.Question[0] = question
|
|
data, err := query.Pack()
|
|
runtimex.PanicOnError(err, "query.Pack failed")
|
|
return data
|
|
}
|
|
|
|
// dnsGenReplyWithError generates a DNS reply for the given
|
|
// query type (e.g., dns.TypeA) using code as the Rcode.
|
|
func dnsGenReplyWithError(rawQuery []byte, code int) []byte {
|
|
query := new(dns.Msg)
|
|
err := query.Unpack(rawQuery)
|
|
runtimex.PanicOnError(err, "query.Unpack failed")
|
|
reply := new(dns.Msg)
|
|
reply.Compress = true
|
|
reply.MsgHdr.RecursionAvailable = true
|
|
reply.SetRcode(query, code)
|
|
data, err := reply.Pack()
|
|
runtimex.PanicOnError(err, "reply.Pack failed")
|
|
return data
|
|
}
|
|
|
|
// dnsGenLookupHostReplySuccess generates a successful DNS reply for the given
|
|
// qtype (e.g., dns.TypeA) containing the given ips... in the answer.
|
|
func dnsGenLookupHostReplySuccess(rawQuery []byte, ips ...string) []byte {
|
|
query := new(dns.Msg)
|
|
err := query.Unpack(rawQuery)
|
|
runtimex.PanicOnError(err, "query.Unpack failed")
|
|
runtimex.PanicIfFalse(len(query.Question) == 1, "more than one question")
|
|
question := query.Question[0]
|
|
runtimex.PanicIfFalse(
|
|
question.Qtype == dns.TypeA || question.Qtype == dns.TypeAAAA,
|
|
"invalid query type (expected A or AAAA)",
|
|
)
|
|
reply := new(dns.Msg)
|
|
reply.Compress = true
|
|
reply.MsgHdr.RecursionAvailable = true
|
|
reply.SetReply(query)
|
|
for _, ip := range ips {
|
|
switch question.Qtype {
|
|
case dns.TypeA:
|
|
if isIPv6(ip) {
|
|
continue
|
|
}
|
|
reply.Answer = append(reply.Answer, &dns.A{
|
|
Hdr: dns.RR_Header{
|
|
Name: dns.Fqdn("x.org"),
|
|
Rrtype: question.Qtype,
|
|
Class: dns.ClassINET,
|
|
Ttl: 0,
|
|
},
|
|
A: net.ParseIP(ip),
|
|
})
|
|
case dns.TypeAAAA:
|
|
if !isIPv6(ip) {
|
|
continue
|
|
}
|
|
reply.Answer = append(reply.Answer, &dns.AAAA{
|
|
Hdr: dns.RR_Header{
|
|
Name: dns.Fqdn("x.org"),
|
|
Rrtype: question.Qtype,
|
|
Class: dns.ClassINET,
|
|
Ttl: 0,
|
|
},
|
|
AAAA: net.ParseIP(ip),
|
|
})
|
|
}
|
|
}
|
|
data, err := reply.Pack()
|
|
runtimex.PanicOnError(err, "reply.Pack failed")
|
|
return data
|
|
}
|
|
|
|
// dnsGenHTTPSReplySuccess generates a successful HTTPS response containing
|
|
// the given (possibly nil) alpns, ipv4s, and ipv6s.
|
|
func dnsGenHTTPSReplySuccess(rawQuery []byte, alpns, ipv4s, ipv6s []string) []byte {
|
|
query := new(dns.Msg)
|
|
err := query.Unpack(rawQuery)
|
|
runtimex.PanicOnError(err, "query.Unpack failed")
|
|
runtimex.PanicIfFalse(len(query.Question) == 1, "expected just a single question")
|
|
question := query.Question[0]
|
|
runtimex.PanicIfFalse(question.Qtype == dns.TypeHTTPS, "expected HTTPS query")
|
|
reply := new(dns.Msg)
|
|
reply.Compress = true
|
|
reply.MsgHdr.RecursionAvailable = true
|
|
reply.SetReply(query)
|
|
answer := &dns.HTTPS{
|
|
SVCB: dns.SVCB{
|
|
Hdr: dns.RR_Header{
|
|
Name: dns.Fqdn("x.org"),
|
|
Rrtype: dns.TypeHTTPS,
|
|
Class: dns.ClassINET,
|
|
Ttl: 100,
|
|
},
|
|
Target: dns.Fqdn("x.org"),
|
|
Value: []dns.SVCBKeyValue{},
|
|
},
|
|
}
|
|
reply.Answer = append(reply.Answer, answer)
|
|
if len(alpns) > 0 {
|
|
answer.Value = append(answer.Value, &dns.SVCBAlpn{Alpn: alpns})
|
|
}
|
|
if len(ipv4s) > 0 {
|
|
var addrs []net.IP
|
|
for _, addr := range ipv4s {
|
|
addrs = append(addrs, net.ParseIP(addr))
|
|
}
|
|
answer.Value = append(answer.Value, &dns.SVCBIPv4Hint{Hint: addrs})
|
|
}
|
|
if len(ipv6s) > 0 {
|
|
var addrs []net.IP
|
|
for _, addr := range ipv6s {
|
|
addrs = append(addrs, net.ParseIP(addr))
|
|
}
|
|
answer.Value = append(answer.Value, &dns.SVCBIPv6Hint{Hint: addrs})
|
|
}
|
|
data, err := reply.Pack()
|
|
runtimex.PanicOnError(err, "reply.Pack failed")
|
|
return data
|
|
}
|
|
|
|
// dnsGenNSReplySuccess generates a successful NS reply using the given names.
|
|
func dnsGenNSReplySuccess(rawQuery []byte, names ...string) []byte {
|
|
query := new(dns.Msg)
|
|
err := query.Unpack(rawQuery)
|
|
runtimex.PanicOnError(err, "query.Unpack failed")
|
|
runtimex.PanicIfFalse(len(query.Question) == 1, "more than one question")
|
|
question := query.Question[0]
|
|
runtimex.PanicIfFalse(question.Qtype == dns.TypeNS, "expected NS query")
|
|
reply := new(dns.Msg)
|
|
reply.Compress = true
|
|
reply.MsgHdr.RecursionAvailable = true
|
|
reply.SetReply(query)
|
|
for _, name := range names {
|
|
reply.Answer = append(reply.Answer, &dns.NS{
|
|
Hdr: dns.RR_Header{
|
|
Name: dns.Fqdn("x.org"),
|
|
Rrtype: question.Qtype,
|
|
Class: dns.ClassINET,
|
|
Ttl: 0,
|
|
},
|
|
Ns: name,
|
|
})
|
|
}
|
|
data, err := reply.Pack()
|
|
runtimex.PanicOnError(err, "reply.Pack failed")
|
|
return data
|
|
}
|