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Cloak
mirror of https://github.com/cbeuw/Cloak
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Add optional encryption

This commit is contained in:
Qian Wang 2019-06-09 21:05:41 +10:00
parent 3e9855191b
commit 0dd52d8570
9 changed files with 143 additions and 39 deletions
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18
cmd/ck-client/ck-client.go
View File

@ -21,6 +21,7 @@ import (
var version string
//TODO: take iv into account
func pipe(dst io.ReadWriteCloser, src io.ReadWriteCloser) {
// The maximum size of TLS message will be 16396+12. 12 because of the stream header
// 16408 is the max TLS message size on Firefox
@ -180,8 +181,21 @@ start:
var UNLIMITED_DOWN int64 = 1e15
var UNLIMITED_UP int64 = 1e15
valve := mux.MakeValve(1e12, 1e12, &UNLIMITED_DOWN, &UNLIMITED_UP)
obfs := mux.MakeObfs(sta.UID)
deobfs := mux.MakeDeobfs(sta.UID)
var crypto mux.Crypto
switch sta.EncryptionMethod {
case 0x00:
crypto = &mux.Plain{}
case 0x01:
crypto, err = mux.MakeAESCipher(sta.UID)
if err != nil {
log.Println(err)
return
}
}
obfs := mux.MakeObfs(sta.UID, crypto)
deobfs := mux.MakeDeobfs(sta.UID, crypto)
sesh := mux.MakeSession(sessionID, valve, obfs, deobfs, util.ReadTLS)
var wg sync.WaitGroup

21
cmd/ck-server/ck-server.go
View File

@ -20,6 +20,7 @@ import (
var version string
//TODO: take iv into account
func pipe(dst io.ReadWriteCloser, src io.ReadWriteCloser) {
// The maximum size of TLS message will be 16396+12. 12 because of the stream header
// 16408 is the max TLS message size on Firefox
@ -69,7 +70,7 @@ func dispatchConnection(conn net.Conn, sta *server.State) {
return
}
isCloak, UID, sessionID, proxyMethod := server.TouchStone(ch, sta)
isCloak, UID, sessionID, proxyMethod, encryptionMethod := server.TouchStone(ch, sta)
if !isCloak {
log.Printf("+1 non Cloak TLS traffic from %v\n", conn.RemoteAddr())
goWeb(data)
@ -148,7 +149,23 @@ func dispatchConnection(conn net.Conn, sta *server.State) {
return
}
sesh, existing, err := user.GetSession(sessionID, mux.MakeObfs(UID), mux.MakeDeobfs(UID), util.ReadTLS)
var crypto mux.Crypto
switch encryptionMethod {
case 0x00:
crypto = &mux.Plain{}
case 0x01:
crypto, err = mux.MakeAESCipher(UID)
if err != nil {
log.Println(err)
goWeb(data)
return
}
default:
goWeb(data)
return
}
sesh, existing, err := user.GetSession(sessionID, mux.MakeObfs(UID, crypto), mux.MakeDeobfs(UID, crypto), util.ReadTLS)
if err != nil {
user.DelSession(sessionID)
log.Println(err)

1
config/ckclient.json
View File

@ -1,5 +1,6 @@
{
"ProxyMethod":"shadowsocks",
"EncryptionMethod":"plain",
"UID":"iGAO85zysIyR4c09CyZSLdNhtP/ckcYu7nIPI082AHA=",
"PublicKey":"IYoUzkle/T/kriE+Ufdm7AHQtIeGnBWbhhlTbmDpUUI=",
"ServerName":"www.bing.com",

11
internal/client/auth.go
View File

@ -34,7 +34,7 @@ func MakeRandomField(sta *State) []byte {
}
func MakeSessionTicket(sta *State) []byte {
// sessionTicket: [marshalled ephemeral pub key 32 bytes][encrypted UID+sessionID 36 bytes and proxy method 16 bytes][padding 108 bytes]
// sessionTicket: [marshalled ephemeral pub key 32 bytes][encrypted UID+sessionID 36 bytes, proxy method 16 bytes, encryption method 1 byte][padding 107 bytes]
// The first 16 bytes of the marshalled ephemeral public key is used as the IV
// for encrypting the UID
tthInterval := sta.Now().Unix() / int64(sta.TicketTimeHint)
@ -52,12 +52,15 @@ func MakeSessionTicket(sta *State) []byte {
ticket := make([]byte, 192)
copy(ticket[0:32], ecdh.Marshal(ephKP.PublicKey))
key := ecdh.GenerateSharedSecret(ephKP.PrivateKey, sta.staticPub)
plain := make([]byte, 52)
plain := make([]byte, 53)
copy(plain, sta.UID)
binary.BigEndian.PutUint32(plain[32:36], sta.sessionID)
copy(plain[36:52], []byte(sta.ProxyMethod))
plain[52] = sta.EncryptionMethod
cipher := util.AESEncrypt(ticket[0:16], key, plain)
copy(ticket[32:84], cipher)
copy(ticket[32:85], cipher)
// The purpose of adding sessionID is that, the generated padding of sessionTicket needs to be unpredictable.
// As shown in auth.go, the padding is generated by a psudo random generator. The seed
// needs to be the same for each TicketTimeHint interval. However the value of epoch/TicketTimeHint
@ -68,6 +71,6 @@ func MakeSessionTicket(sta *State) []byte {
// With the sessionID value generated at startup of ckclient and used as a part of the seed, the
// sessionTicket is still identical for each TicketTimeHint interval, but others won't be able to know
// how it was generated. It will also be different for each client.
copy(ticket[84:192], util.PsudoRandBytes(108, tthInterval+int64(sta.sessionID)))
copy(ticket[85:192], util.PsudoRandBytes(107, tthInterval+int64(sta.sessionID)))
return ticket
}

37
internal/client/state.go
View File

@ -14,13 +14,14 @@ import (
)
type rawConfig struct {
ServerName string
ProxyMethod string
UID string
PublicKey string
TicketTimeHint int
BrowserSig string
NumConn int
ServerName string
ProxyMethod string
EncryptionMethod string
UID string
PublicKey string
TicketTimeHint int
BrowserSig string
NumConn int
}
// State stores global variables
@ -37,11 +38,12 @@ type State struct {
keyPairsM sync.RWMutex
keyPairs map[int64]*keyPair
ProxyMethod string
TicketTimeHint int
ServerName string
BrowserSig string
NumConn int
ProxyMethod string
EncryptionMethod byte
TicketTimeHint int
ServerName string
BrowserSig string
NumConn int
}
func InitState(localHost, localPort, remoteHost, remotePort string, nowFunc func() time.Time) *State {
@ -104,11 +106,22 @@ func (sta *State) ParseConfig(conf string) (err error) {
if err != nil {
return err
}
switch preParse.EncryptionMethod {
case "plain":
sta.EncryptionMethod = 0x00
case "aes":
sta.EncryptionMethod = 0x01
default:
return errors.New("Unknown encryption method")
}
sta.ProxyMethod = preParse.ProxyMethod
sta.ServerName = preParse.ServerName
sta.TicketTimeHint = preParse.TicketTimeHint
sta.BrowserSig = preParse.BrowserSig
sta.NumConn = preParse.NumConn
uid, err := base64.StdEncoding.DecodeString(preParse.UID)
if err != nil {
return errors.New("Failed to parse UID: " + err.Error())

53
internal/multiplex/crypto.go Normal file
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@ -0,0 +1,53 @@
package multiplex
import (
"crypto/aes"
"crypto/cipher"
"crypto/rand"
)
type Crypto interface {
encrypt([]byte) []byte
decrypt([]byte) []byte
}
type Plain struct{}
func (p *Plain) encrypt(plaintext []byte) []byte {
return plaintext
}
func (p *Plain) decrypt(buf []byte) []byte {
return buf
}
type AES struct {
cipher cipher.Block
}
func MakeAESCipher(key []byte) (*AES, error) {
c, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
ret := AES{
c,
}
return &ret, nil
}
func (a *AES) encrypt(plaintext []byte) []byte {
iv := make([]byte, 16)
rand.Read(iv)
ciphertext := make([]byte, 16+len(plaintext))
stream := cipher.NewCTR(a.cipher, iv)
stream.XORKeyStream(ciphertext[16:], plaintext)
copy(ciphertext[:16], iv)
return ciphertext
}
func (a *AES) decrypt(buf []byte) []byte {
stream := cipher.NewCTR(a.cipher, buf[0:16])
stream.XORKeyStream(buf[16:], buf[16:])
return buf[16:]
}

23
internal/multiplex/obfs.go
View File

@ -15,15 +15,13 @@ var u32 = binary.BigEndian.Uint32
const headerLen = 12
// For each frame, the three parts of the header is xored with three keys.
// The keys are generated from the SID and the payload of the frame.
func genXorKeys(key, nonce []byte) (i uint32, ii uint32, iii uint8) {
h := sha1.New()
hashed := h.Sum(append(key, nonce...))
return u32(hashed[0:4]), u32(hashed[4:8]), hashed[8]
}
func MakeObfs(key []byte) Obfser {
func MakeObfs(key []byte, algo Crypto) Obfser {
obfs := func(f *Frame) ([]byte, error) {
obfsedHeader := make([]byte, headerLen)
// header: [StreamID 4 bytes][Seq 4 bytes][Closing 1 byte][Nonce 3 bytes]
@ -33,22 +31,24 @@ func MakeObfs(key []byte) Obfser {
binary.BigEndian.PutUint32(obfsedHeader[4:8], f.Seq^ii)
obfsedHeader[8] = f.Closing ^ iii
encryptedPayload := algo.encrypt(f.Payload)
// Composing final obfsed message
// We don't use util.AddRecordLayer here to avoid unnecessary malloc
obfsed := make([]byte, 5+headerLen+len(f.Payload))
obfsed := make([]byte, 5+headerLen+len(encryptedPayload))
obfsed[0] = 0x17
obfsed[1] = 0x03
obfsed[2] = 0x03
binary.BigEndian.PutUint16(obfsed[3:5], uint16(headerLen+len(f.Payload)))
binary.BigEndian.PutUint16(obfsed[3:5], uint16(headerLen+len(encryptedPayload)))
copy(obfsed[5:5+headerLen], obfsedHeader)
copy(obfsed[5+headerLen:], f.Payload)
copy(obfsed[5+headerLen:], encryptedPayload)
// obfsed: [record layer 5 bytes][cipherheader 12 bytes][payload]
return obfsed, nil
}
return obfs
}
func MakeDeobfs(key []byte) Deobfser {
func MakeDeobfs(key []byte, algo Crypto) Deobfser {
deobfs := func(in []byte) (*Frame, error) {
if len(in) < 5+headerLen {
return nil, errors.New("Input cannot be shorter than 17 bytes")
@ -58,13 +58,16 @@ func MakeDeobfs(key []byte) Deobfser {
streamID := u32(peeled[0:4]) ^ i
seq := u32(peeled[4:8]) ^ ii
closing := peeled[8] ^ iii
payload := make([]byte, len(peeled)-headerLen)
copy(payload, peeled[headerLen:])
rawPayload := make([]byte, len(peeled)-headerLen)
copy(rawPayload, peeled[headerLen:])
decryptedPayload := algo.decrypt(rawPayload)
ret := &Frame{
StreamID: streamID,
Seq: seq,
Closing: closing,
Payload: payload,
Payload: decryptedPayload,
}
return ret, nil
}

16
internal/server/auth.go
View File

@ -12,12 +12,12 @@ import (
)
// input ticket, return UID
func decryptSessionTicket(staticPv crypto.PrivateKey, ticket []byte) ([]byte, uint32, string) {
func decryptSessionTicket(staticPv crypto.PrivateKey, ticket []byte) ([]byte, uint32, string, byte) {
ephPub, _ := ecdh.Unmarshal(ticket[0:32])
key := ecdh.GenerateSharedSecret(staticPv, ephPub)
plain := util.AESDecrypt(ticket[0:16], key, ticket[32:84])
plain := util.AESDecrypt(ticket[0:16], key, ticket[32:85])
sessionID := binary.BigEndian.Uint32(plain[32:36])
return plain[0:32], sessionID, string(bytes.Trim(plain[36:52], "\x00"))
return plain[0:32], sessionID, string(bytes.Trim(plain[36:52], "\x00")), plain[52]
}
func validateRandom(random []byte, UID []byte, time int64) bool {
@ -32,7 +32,7 @@ func validateRandom(random []byte, UID []byte, time int64) bool {
h.Write(preHash)
return bytes.Equal(h.Sum(nil)[0:16], random[16:32])
}
func TouchStone(ch *ClientHello, sta *State) (isCK bool, UID []byte, sessionID uint32, proxyMethod string) {
func TouchStone(ch *ClientHello, sta *State) (isCK bool, UID []byte, sessionID uint32, proxyMethod string, encryptionMethod byte) {
var random [32]byte
copy(random[:], ch.random)
@ -43,17 +43,17 @@ func TouchStone(ch *ClientHello, sta *State) (isCK bool, UID []byte, sessionID u
if used != 0 {
log.Println("Replay! Duplicate random")
return false, nil, 0, ""
return
}
ticket := ch.extensions[[2]byte{0x00, 0x23}]
if len(ticket) < 68 {
return false, nil, 0, ""
return
}
UID, sessionID, proxyMethod = decryptSessionTicket(sta.staticPv, ticket)
UID, sessionID, proxyMethod, encryptionMethod = decryptSessionTicket(sta.staticPv, ticket)
isCK = validateRandom(ch.random, UID, sta.Now().Unix())
if !isCK {
return false, nil, 0, ""
return
}
return

2
internal/server/auth_test.go
View File

@ -16,7 +16,7 @@ func TestDecryptSessionTicket(t *testing.T) {
staticPv, _ := ecdh.Unmarshal(pvb)
sessionTicket, _ := hex.DecodeString("f586223b50cada583d61dc9bf3d01cc3a45aab4b062ed6a31ead0badb87f7761aab4f9f737a1d8ff2a2aa4d50ceb808844588ee3c8fdf36c33a35ef5003e287337659c8164a7949e9e63623090763fc24d0386c8904e47bdd740e09dd9b395c72de669629c2a865ed581452d23306adf26de0c8a46ee05e3dac876f2bcd9a2de946d319498f579383d06b3e66b3aca05f533fdc5f017eeba45b42080aabd4f71151fa0dfc1b0e23be4ed3abdb47adc0d5740ca7b7689ad34426309fb6984a086")
decryUID, decrySessionID, _ := decryptSessionTicket(staticPv, sessionTicket)
decryUID, decrySessionID, _, _ := decryptSessionTicket(staticPv, sessionTicket)
if !bytes.Equal(decryUID, UID) {
t.Error(
"For", "UID",