FILE / ScuroNeko/mtg

mtglib/internal/tls/fake/client_side_test.go

Исходный файл и его история в репозитории.
FILE 38abee7d7f796ffaf6716985a0dcc6c3fe4a8f1a
Files
mtg/mtglib/internal/tls/fake/client_side_test.go
T
appolimp 38abee7d7f Support fragmented TLS handshake records
DPI bypass tools like ByeDPI fragment a single TLS record into multiple
records to evade censorship. This broke ReadClientHello because it
assumed the entire ClientHello arrives in one TLS record.

Add reassembleTLSHandshake that reads continuation records and
reconstructs a single TLS record before parsing and HMAC verification.
Per RFC 5246 Section 6.2.1, handshake messages may be fragmented
across multiple records — this is valid TLS behavior.
2026-04-01 09:05:24 +03:00

668 lines
19 KiB
Go

package fake_test
import (
"bytes"
"encoding/binary"
"encoding/json"
"errors"
"io"
"os"
"testing"
"time"
"github.com/9seconds/mtg/v2/internal/testlib"
"github.com/9seconds/mtg/v2/mtglib"
"github.com/9seconds/mtg/v2/mtglib/internal/tls"
"github.com/9seconds/mtg/v2/mtglib/internal/tls/fake"
"github.com/stretchr/testify/mock"
"github.com/stretchr/testify/require"
"github.com/stretchr/testify/suite"
)
const (
TolerateTime = 365 * 30 * 24 * time.Hour
)
type parseClientHelloConnMock struct {
testlib.EssentialsConnMock
readBuf *bytes.Buffer
}
func (m *parseClientHelloConnMock) Read(p []byte) (int, error) {
return m.readBuf.Read(p)
}
type ParseClientHelloTestSuite struct {
suite.Suite
secret mtglib.Secret
readBuf *bytes.Buffer
connMock *parseClientHelloConnMock
}
func (suite *ParseClientHelloTestSuite) SetupSuite() {
parsed, err := mtglib.ParseSecret("ee367a189aee18fa31c190054efd4a8e9573746f726167652e676f6f676c65617069732e636f6d")
require.NoError(suite.T(), err)
suite.secret = parsed
}
func (suite *ParseClientHelloTestSuite) SetupTest() {
suite.readBuf = &bytes.Buffer{}
suite.connMock = &parseClientHelloConnMock{
readBuf: suite.readBuf,
}
suite.connMock.
On("SetReadDeadline", mock.AnythingOfType("time.Time")).
Twice().
Return(nil)
}
func (suite *ParseClientHelloTestSuite) TearDownTest() {
suite.connMock.AssertExpectations(suite.T())
}
type ParseClientHello_TLSHeaderTestSuite struct {
ParseClientHelloTestSuite
}
func (suite *ParseClientHello_TLSHeaderTestSuite) TestEmpty() {
suite.connMock.ExpectedCalls = []*mock.Call{}
suite.connMock.
On("SetReadDeadline", mock.AnythingOfType("time.Time")).
Once().
Return(errors.New("fail"))
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "fail")
}
func (suite *ParseClientHello_TLSHeaderTestSuite) TestNothing() {
suite.connMock.ExpectedCalls = []*mock.Call{}
suite.connMock.
On("SetReadDeadline", mock.AnythingOfType("time.Time")).
Twice().
Return(nil)
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorIs(err, io.EOF)
}
func (suite *ParseClientHello_TLSHeaderTestSuite) TestUnknownRecord() {
suite.readBuf.Write([]byte{
10,
3, 3,
0, 0,
})
suite.readBuf.WriteByte(10)
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "unexpected record type 0xa")
}
func (suite *ParseClientHello_TLSHeaderTestSuite) TestUnknownProtocolVersion() {
suite.readBuf.Write([]byte{
tls.TypeHandshake,
3, 3,
0, 0,
})
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "unexpected protocol version")
}
func (suite *ParseClientHello_TLSHeaderTestSuite) TestCannotReadRestOfRecord() {
suite.readBuf.Write([]byte{
tls.TypeHandshake,
3, 1,
0, 10,
})
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorIs(err, io.EOF)
}
type ParseClientHelloHandshakeTestSuite struct {
ParseClientHelloTestSuite
}
func (suite *ParseClientHelloHandshakeTestSuite) SetupTest() {
suite.ParseClientHelloTestSuite.SetupTest()
suite.readBuf.Write([]byte{
tls.TypeHandshake,
3, 1,
0,
})
}
func (suite *ParseClientHelloHandshakeTestSuite) TestCannotReadHeader() {
suite.readBuf.Write([]byte{
1,
10,
})
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "cannot read handshake header")
}
func (suite *ParseClientHelloHandshakeTestSuite) TestIncorrectHandshakeType() {
suite.readBuf.Write([]byte{
4,
10, 0, 0, 0,
})
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "incorrect handshake type")
}
func (suite *ParseClientHelloHandshakeTestSuite) TestCannotReadHandshake() {
suite.readBuf.Write([]byte{
4 + 3,
10, 0, 0, 0,
})
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorIs(err, io.EOF)
}
type ParseClientHelloHandshakeBodyTestSuite struct {
ParseClientHelloTestSuite
}
func (suite *ParseClientHelloHandshakeBodyTestSuite) SetupTest() {
suite.ParseClientHelloTestSuite.SetupTest()
suite.readBuf.Write([]byte{
tls.TypeHandshake,
3, 1,
0,
})
}
func (suite *ParseClientHelloHandshakeBodyTestSuite) writeBody(body []byte) {
suite.readBuf.WriteByte(byte(4 + len(body)))
suite.readBuf.Write([]byte{
fake.TypeHandshakeClient,
0, 0, byte(len(body)),
})
suite.readBuf.Write(body)
}
func (suite *ParseClientHelloHandshakeBodyTestSuite) TestCannotReadVersion() {
suite.writeBody(nil)
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "cannot read client version")
}
func (suite *ParseClientHelloHandshakeBodyTestSuite) TestCannotReadRandom() {
suite.writeBody([]byte{3, 3})
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "cannot read client random")
}
func (suite *ParseClientHelloHandshakeBodyTestSuite) TestCannotReadSessionIDLength() {
body := make([]byte, 2+fake.RandomLen)
suite.writeBody(body)
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "cannot read session ID length")
}
func (suite *ParseClientHelloHandshakeBodyTestSuite) TestCannotReadSessionID() {
body := make([]byte, 2+fake.RandomLen+1)
body[2+fake.RandomLen] = 32
suite.writeBody(body)
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "cannot read session id")
}
func (suite *ParseClientHelloHandshakeBodyTestSuite) TestCannotReadCipherSuiteLength() {
body := make([]byte, 2+fake.RandomLen+1)
suite.writeBody(body)
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "cannot read cipher suite length")
}
func (suite *ParseClientHelloHandshakeBodyTestSuite) TestCannotReadFirstCipherSuite() {
body := make([]byte, 2+fake.RandomLen+1+2)
suite.writeBody(body)
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "cannot read first cipher suite")
}
func (suite *ParseClientHelloHandshakeBodyTestSuite) TestCannotSkipRemainingCipherSuites() {
body := make([]byte, 2+fake.RandomLen+1+2+2)
binary.BigEndian.PutUint16(body[2+fake.RandomLen+1:], 4)
suite.writeBody(body)
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "cannot skip remaining cipher suites")
}
func (suite *ParseClientHelloHandshakeBodyTestSuite) TestCannotReadCompressionMethodsLength() {
body := make([]byte, 2+fake.RandomLen+1+2+2)
binary.BigEndian.PutUint16(body[2+fake.RandomLen+1:], 2)
suite.writeBody(body)
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "cannot read compression methods length")
}
func (suite *ParseClientHelloHandshakeBodyTestSuite) TestCannotSkipCompressionMethods() {
body := make([]byte, 2+fake.RandomLen+1+2+2+1)
binary.BigEndian.PutUint16(body[2+fake.RandomLen+1:], 2)
body[2+fake.RandomLen+1+2+2] = 1
suite.writeBody(body)
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "cannot skip compression methods")
}
type ParseClientHelloSNITestSuite struct {
ParseClientHelloTestSuite
}
func (suite *ParseClientHelloSNITestSuite) SetupTest() {
suite.ParseClientHelloTestSuite.SetupTest()
suite.readBuf.Write([]byte{
tls.TypeHandshake,
3, 1,
0,
})
}
func (suite *ParseClientHelloSNITestSuite) writeExtensions(extensions []byte) {
handshakeBodyLen := 41 + len(extensions)
suite.readBuf.WriteByte(byte(4 + handshakeBodyLen))
suite.readBuf.Write([]byte{
fake.TypeHandshakeClient,
0, 0, byte(handshakeBodyLen),
})
// version(2) + random(32) + sessionIDLen(1) + cipherSuiteLen(2) +
// cipherSuite(2) + compressionLen(1) + compression(1) = 41
body := make([]byte, 41)
binary.BigEndian.PutUint16(body[35:], 2)
body[39] = 1
suite.readBuf.Write(body)
suite.readBuf.Write(extensions)
}
func (suite *ParseClientHelloSNITestSuite) TestCannotReadExtensionsLength() {
suite.writeExtensions(nil)
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "cannot read length of TLS extensions")
}
func (suite *ParseClientHelloSNITestSuite) TestCannotReadExtensions() {
suite.writeExtensions([]byte{0, 10})
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "cannot read extensions")
}
func (suite *ParseClientHelloSNITestSuite) TestCannotReadExtensionType() {
suite.writeExtensions([]byte{0, 1, 0xAB})
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "cannot read extension type")
}
func (suite *ParseClientHelloSNITestSuite) TestCannotReadExtensionLength() {
suite.writeExtensions([]byte{0, 2, 0xFF, 0xFF})
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "length:")
}
func (suite *ParseClientHelloSNITestSuite) TestCannotReadExtensionData() {
suite.writeExtensions([]byte{0, 4, 0xFF, 0xFF, 0, 5})
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "data: len")
}
func (suite *ParseClientHelloSNITestSuite) TestCannotReadSNIRecordLength() {
suite.writeExtensions([]byte{0, 5, 0, 0, 0, 1, 0xAB})
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "cannot read the length of the SNI record")
}
func (suite *ParseClientHelloSNITestSuite) TestCannotReadSNIListType() {
suite.writeExtensions([]byte{0, 6, 0, 0, 0, 2, 0, 1})
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "cannot read SNI list type")
}
func (suite *ParseClientHelloSNITestSuite) TestIncorrectSNIListType() {
suite.writeExtensions([]byte{0, 7, 0, 0, 0, 3, 0, 1, 5})
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "incorrect SNI list type")
}
func (suite *ParseClientHelloSNITestSuite) TestCannotReadHostnameLength() {
suite.writeExtensions([]byte{0, 8, 0, 0, 0, 4, 0, 2, 0, 0xAB})
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "incorrect length of the hostname")
}
func (suite *ParseClientHelloSNITestSuite) TestCannotReadHostname() {
suite.writeExtensions([]byte{0, 9, 0, 0, 0, 5, 0, 3, 0, 0, 5})
_, err := fake.ReadClientHello(suite.connMock, suite.secret.Key[:], suite.secret.Host, TolerateTime)
suite.ErrorContains(err, "incorrect length of SNI hostname")
}
func TestParseClientHelloTLSHeader(t *testing.T) {
t.Parallel()
suite.Run(t, &ParseClientHello_TLSHeaderTestSuite{})
}
func TestParseClientHelloHandshake(t *testing.T) {
t.Parallel()
suite.Run(t, &ParseClientHelloHandshakeTestSuite{})
}
func TestParseClientHelloHandshakeBody(t *testing.T) {
t.Parallel()
suite.Run(t, &ParseClientHelloHandshakeBodyTestSuite{})
}
func TestParseClientHelloSNI(t *testing.T) {
t.Parallel()
suite.Run(t, &ParseClientHelloSNITestSuite{})
}
// fragmentTLSRecord splits a single TLS record into n TLS records by
// dividing the payload into roughly equal parts. Each part gets its own
// TLS record header with the same record type and version.
func fragmentTLSRecord(t testing.TB, full []byte, n int) []byte {
t.Helper()
recordType := full[0]
version := full[1:3]
payload := full[tls.SizeHeader:]
chunkSize := len(payload) / n
result := &bytes.Buffer{}
for i := 0; i < n; i++ {
start := i * chunkSize
end := start + chunkSize
if i == n-1 {
end = len(payload)
}
chunk := payload[start:end]
result.WriteByte(recordType)
result.Write(version)
require.NoError(t, binary.Write(result, binary.BigEndian, uint16(len(chunk))))
result.Write(chunk)
}
return result.Bytes()
}
// splitPayloadAt creates two TLS records from a single record by splitting
// the payload at the given byte position.
func splitPayloadAt(t testing.TB, full []byte, pos int) []byte {
t.Helper()
payload := full[tls.SizeHeader:]
buf := &bytes.Buffer{}
buf.WriteByte(tls.TypeHandshake)
buf.Write(full[1:3])
require.NoError(t, binary.Write(buf, binary.BigEndian, uint16(pos)))
buf.Write(payload[:pos])
buf.WriteByte(tls.TypeHandshake)
buf.Write(full[1:3])
require.NoError(t, binary.Write(buf, binary.BigEndian, uint16(len(payload)-pos)))
buf.Write(payload[pos:])
return buf.Bytes()
}
type ParseClientHelloFragmentedTestSuite struct {
suite.Suite
secret mtglib.Secret
snapshot *clientHelloSnapshot
}
func (s *ParseClientHelloFragmentedTestSuite) SetupSuite() {
parsed, err := mtglib.ParseSecret(
"ee367a189aee18fa31c190054efd4a8e9573746f726167652e676f6f676c65617069732e636f6d",
)
require.NoError(s.T(), err)
s.secret = parsed
fileData, err := os.ReadFile("testdata/client-hello-ok-19dfe38384b9884b.json")
require.NoError(s.T(), err)
s.snapshot = &clientHelloSnapshot{}
require.NoError(s.T(), json.Unmarshal(fileData, s.snapshot))
}
func (s *ParseClientHelloFragmentedTestSuite) makeConn(data []byte) *parseClientHelloConnMock {
readBuf := &bytes.Buffer{}
readBuf.Write(data)
connMock := &parseClientHelloConnMock{
readBuf: readBuf,
}
connMock.
On("SetReadDeadline", mock.AnythingOfType("time.Time")).
Twice().
Return(nil)
return connMock
}
func (s *ParseClientHelloFragmentedTestSuite) TestReassemblySuccess() {
full := s.snapshot.GetFull()
tests := []struct {
name string
data []byte
}{
{"two equal fragments", fragmentTLSRecord(s.T(), full, 2)},
{"three equal fragments", fragmentTLSRecord(s.T(), full, 3)},
{"single byte first fragment", splitPayloadAt(s.T(), full, 1)},
{"three byte first fragment", splitPayloadAt(s.T(), full, 3)},
}
for _, tt := range tests {
s.Run(tt.name, func() {
connMock := s.makeConn(tt.data)
defer connMock.AssertExpectations(s.T())
hello, err := fake.ReadClientHello(
connMock,
s.secret.Key[:],
s.secret.Host,
TolerateTime,
)
s.Require().NoError(err)
s.Equal(s.snapshot.GetRandom(), hello.Random[:])
s.Equal(s.snapshot.GetSessionID(), hello.SessionID)
s.Equal(uint16(s.snapshot.CipherSuite), hello.CipherSuite)
})
}
}
func (s *ParseClientHelloFragmentedTestSuite) TestReassemblyErrors() {
full := s.snapshot.GetFull()
payload := full[tls.SizeHeader:]
tests := []struct {
name string
buildData func() []byte
errMsg string
}{
{
name: "wrong continuation record type",
buildData: func() []byte {
buf := &bytes.Buffer{}
buf.WriteByte(tls.TypeHandshake)
buf.Write(full[1:3])
require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(10)))
buf.Write(payload[:10])
// Wrong type: application data instead of handshake
buf.WriteByte(tls.TypeApplicationData)
buf.Write(full[1:3])
require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(len(payload)-10)))
buf.Write(payload[10:])
return buf.Bytes()
},
errMsg: "unexpected continuation record type",
},
{
name: "too many continuation records",
buildData: func() []byte {
// Handshake header claiming 256 bytes, but we only send 1 byte per continuation
handshakePayload := []byte{0x01, 0x00, 0x01, 0x00}
buf := &bytes.Buffer{}
buf.WriteByte(tls.TypeHandshake)
buf.Write([]byte{3, 1})
require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(len(handshakePayload))))
buf.Write(handshakePayload)
for range 11 {
buf.WriteByte(tls.TypeHandshake)
buf.Write([]byte{3, 1})
require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(1)))
buf.WriteByte(0xAB)
}
return buf.Bytes()
},
errMsg: "too many continuation records",
},
{
name: "zero-length continuation record",
buildData: func() []byte {
buf := &bytes.Buffer{}
buf.WriteByte(tls.TypeHandshake)
buf.Write(full[1:3])
require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(10)))
buf.Write(payload[:10])
// Valid header but zero-length payload
buf.WriteByte(tls.TypeHandshake)
buf.Write(full[1:3])
require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(0)))
return buf.Bytes()
},
errMsg: "zero-length continuation record",
},
{
name: "wrong continuation record version",
buildData: func() []byte {
buf := &bytes.Buffer{}
buf.WriteByte(tls.TypeHandshake)
buf.Write(full[1:3])
require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(10)))
buf.Write(payload[:10])
// Wrong version: 3.3 instead of 3.1
buf.WriteByte(tls.TypeHandshake)
buf.Write([]byte{3, 3})
require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(len(payload)-10)))
buf.Write(payload[10:])
return buf.Bytes()
},
errMsg: "unexpected continuation record version",
},
{
name: "handshake message too large",
buildData: func() []byte {
// Handshake header claiming 0x010000 (65536) bytes — exceeds 0xFFFF limit
handshakePayload := []byte{0x01, 0x01, 0x00, 0x00}
buf := &bytes.Buffer{}
buf.WriteByte(tls.TypeHandshake)
buf.Write([]byte{3, 1})
require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(len(handshakePayload))))
buf.Write(handshakePayload)
return buf.Bytes()
},
errMsg: "handshake message too large",
},
{
name: "truncated continuation record header",
buildData: func() []byte {
buf := &bytes.Buffer{}
buf.WriteByte(tls.TypeHandshake)
buf.Write(full[1:3])
require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(10)))
buf.Write(payload[:10])
// Connection ends mid-header (only 2 bytes)
buf.WriteByte(tls.TypeHandshake)
buf.WriteByte(3)
return buf.Bytes()
},
errMsg: "cannot read continuation record header",
},
{
name: "truncated continuation record payload",
buildData: func() []byte {
buf := &bytes.Buffer{}
buf.WriteByte(tls.TypeHandshake)
buf.Write(full[1:3])
require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(10)))
buf.Write(payload[:10])
// Claims 100 bytes but no payload follows
buf.WriteByte(tls.TypeHandshake)
buf.Write(full[1:3])
require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(100)))
return buf.Bytes()
},
errMsg: "cannot read continuation record payload",
},
}
for _, tt := range tests {
s.Run(tt.name, func() {
connMock := s.makeConn(tt.buildData())
defer connMock.AssertExpectations(s.T())
_, err := fake.ReadClientHello(
connMock,
s.secret.Key[:],
s.secret.Host,
TolerateTime,
)
s.ErrorContains(err, tt.errMsg)
})
}
}
func TestParseClientHelloFragmented(t *testing.T) {
t.Parallel()
suite.Run(t, &ParseClientHelloFragmentedTestSuite{})
}