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Mainly reverse VLESS Client Hello

Browse Source 
https://github.com/XTLS/Xray-core/pull/4952#issuecomment-3176751311
This commit is contained in:
RPRX 2025-08-12 11:51:28 +00:00 committed by GitHub
parent 7ffb555fc8
commit ec1cc35188
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
4 changed files with 143 additions and 123 deletions
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70
proxy/vless/encryption/client.go
View File

@ -20,14 +20,15 @@ import (
var ClientCipher byte
func init() {
if !protocol.HasAESGCMHardwareSupport {
if protocol.HasAESGCMHardwareSupport {
ClientCipher = 1
}
}
type ClientInstance struct {
sync.RWMutex
eKeyNfs *mlkem.EncapsulationKey768
nfsEKey *mlkem.EncapsulationKey768
nfsEKeyBytes []byte
xor uint32
minutes time.Duration
expire time.Time
@ -48,19 +49,22 @@ type ClientConn struct {
peerCache []byte
}
func (i *ClientInstance) Init(eKeyNfsData []byte, xor uint32, minutes time.Duration) (err error) {
i.eKeyNfs, err = mlkem.NewEncapsulationKey768(eKeyNfsData)
func (i *ClientInstance) Init(nfsEKeyBytes []byte, xor uint32, minutes time.Duration) (err error) {
i.nfsEKey, err = mlkem.NewEncapsulationKey768(nfsEKeyBytes)
if xor > 0 {
i.nfsEKeyBytes = nfsEKeyBytes
i.xor = xor
}
i.minutes = minutes
return
}
func (i *ClientInstance) Handshake(conn net.Conn) (net.Conn, error) {
if i.eKeyNfs == nil {
if i.nfsEKey == nil {
return nil, errors.New("uninitialized")
}
if i.xor == 1 {
conn = NewXorConn(conn, i.eKeyNfs.Bytes())
if i.xor > 0 {
conn = NewXorConn(conn, i.nfsEKeyBytes)
}
c := &ClientConn{Conn: conn}
@ -76,18 +80,19 @@ func (i *ClientInstance) Handshake(conn net.Conn) (net.Conn, error) {
i.RUnlock()
}
nfsKey, encapsulatedNfsKey := i.eKeyNfs.Encapsulate()
seed := make([]byte, 64)
rand.Read(seed)
dKeyPfs, _ := mlkem.NewDecapsulationKey768(seed)
eKeyPfs := dKeyPfs.EncapsulationKey().Bytes()
padding := crypto.RandBetween(100, 1000)
pfsDKeySeed := make([]byte, 64)
rand.Read(pfsDKeySeed)
pfsDKey, _ := mlkem.NewDecapsulationKey768(pfsDKeySeed)
pfsEKeyBytes := pfsDKey.EncapsulationKey().Bytes()
nfsKey, encapsulatedNfsKey := i.nfsEKey.Encapsulate()
paddingLen := crypto.RandBetween(100, 1000)
clientHello := make([]byte, 1088+1184+1+5+padding)
copy(clientHello, encapsulatedNfsKey)
copy(clientHello[1088:], eKeyPfs)
clientHello[2272] = ClientCipher
encodeHeader(clientHello[2273:], int(padding))
clientHello := make([]byte, 1+1184+1088+5+paddingLen)
clientHello[0] = ClientCipher
copy(clientHello[1:], pfsEKeyBytes)
copy(clientHello[1185:], encapsulatedNfsKey)
encodeHeader(clientHello[2273:], int(paddingLen))
rand.Read(clientHello[2278:])
if _, err := c.Conn.Write(clientHello); err != nil {
return nil, err
@ -101,16 +106,16 @@ func (i *ClientInstance) Handshake(conn net.Conn) (net.Conn, error) {
encapsulatedPfsKey := peerServerHello[:1088]
c.ticket = peerServerHello[1088:]
pfsKey, err := dKeyPfs.Decapsulate(encapsulatedPfsKey)
pfsKey, err := pfsDKey.Decapsulate(encapsulatedPfsKey)
if err != nil {
return nil, err
}
c.baseKey = append(nfsKey, pfsKey...)
c.baseKey = append(pfsKey, nfsKey...)
authKey := make([]byte, 32)
hkdf.New(sha256.New, c.baseKey, encapsulatedNfsKey, eKeyPfs).Read(authKey)
nonce := make([]byte, 12)
VLESS, _ := newAead(ClientCipher, authKey).Open(nil, nonce, c.ticket, encapsulatedPfsKey)
hkdf.New(sha256.New, c.baseKey, encapsulatedPfsKey, encapsulatedNfsKey).Read(authKey)
nonce := [12]byte{ClientCipher}
VLESS, _ := newAead(ClientCipher, authKey).Open(nil, nonce[:], c.ticket, pfsEKeyBytes)
if !bytes.Equal(VLESS, []byte("VLESS")) { // TODO: more message
return nil, errors.New("invalid server").AtError()
}
@ -130,6 +135,12 @@ func (c *ClientConn) Write(b []byte) (int, error) {
if len(b) == 0 {
return 0, nil
}
for n := 0; n < len(b); {
b := b[n:]
if len(b) > 8192 {
b = b[:8192] // for avoiding another copy() in server's Read()
}
n += len(b)
var data []byte
if c.aead == nil {
c.random = make([]byte, 32)
@ -153,10 +164,11 @@ func (c *ClientConn) Write(b []byte) (int, error) {
if _, err := c.Conn.Write(data); err != nil {
return 0, err
}
}
return len(b), nil
}
func (c *ClientConn) Read(b []byte) (int, error) { // after first Write()
func (c *ClientConn) Read(b []byte) (int, error) {
if len(b) == 0 {
return 0, nil
}
@ -167,11 +179,11 @@ func (c *ClientConn) Read(b []byte) (int, error) { // after first Write()
if _, err := io.ReadFull(c.Conn, peerHeader); err != nil {
return 0, err
}
peerPadding, _ := decodeHeader(peerHeader)
if peerPadding == 0 {
peerPaddingLen, _ := decodeHeader(peerHeader)
if peerPaddingLen == 0 {
break
}
if _, err := io.ReadFull(c.Conn, make([]byte, peerPadding)); err != nil {
if _, err := io.ReadFull(c.Conn, make([]byte, peerPaddingLen)); err != nil {
return 0, err
}
}
@ -186,7 +198,7 @@ func (c *ClientConn) Read(b []byte) (int, error) { // after first Write()
return 0, err
}
if c.random == nil {
return 0, errors.New("can not Read() first")
return 0, errors.New("empty c.random")
}
peerKey := make([]byte, 32)
hkdf.New(sha256.New, c.baseKey, peerRandom, c.random).Read(peerKey)
@ -218,7 +230,7 @@ func (c *ClientConn) Read(b []byte) (int, error) { // after first Write()
}
dst := peerData[:peerLength-16]
if len(dst) <= len(b) {
dst = b[:len(dst)] // max=8192 is recommended for peer
dst = b[:len(dst)] // avoids another copy()
}
_, err = c.peerAead.Open(dst[:0], c.peerNonce, peerData, peerHeader)
increaseNonce(c.peerNonce)

18
proxy/vless/encryption/common.go
View File

@ -28,18 +28,14 @@ func decodeHeader(b []byte) (int, error) {
return 0, errors.New("invalid record's header")
}
func newAead(c byte, k []byte) cipher.AEAD {
switch c {
case 0:
if block, err := aes.NewCipher(k); err == nil {
aead, _ := cipher.NewGCM(block)
return aead
func newAead(c byte, k []byte) (aead cipher.AEAD) {
if c&1 == 1 {
block, _ := aes.NewCipher(k)
aead, _ = cipher.NewGCM(block)
} else {
aead, _ = chacha20poly1305.New(k)
}
case 1:
aead, _ := chacha20poly1305.New(k)
return aead
}
return nil
return
}
func increaseNonce(nonce []byte) {

76
proxy/vless/encryption/server.go
View File

@ -25,7 +25,8 @@ type ServerSession struct {
type ServerInstance struct {
sync.RWMutex
dKeyNfs *mlkem.DecapsulationKey768
nfsDKey *mlkem.DecapsulationKey768
nfsEKeyBytes []byte
xor uint32
minutes time.Duration
sessions map[[21]byte]*ServerSession
@ -44,9 +45,12 @@ type ServerConn struct {
nonce []byte
}
func (i *ServerInstance) Init(dKeyNfsData []byte, xor uint32, minutes time.Duration) (err error) {
i.dKeyNfs, err = mlkem.NewDecapsulationKey768(dKeyNfsData)
func (i *ServerInstance) Init(nfsDKeySeed []byte, xor uint32, minutes time.Duration) (err error) {
i.nfsDKey, err = mlkem.NewDecapsulationKey768(nfsDKeySeed)
if xor > 0 {
i.nfsEKeyBytes = i.nfsDKey.EncapsulationKey().Bytes()
i.xor = xor
}
if minutes > 0 {
i.minutes = minutes
i.sessions = make(map[[21]byte]*ServerSession)
@ -55,9 +59,9 @@ func (i *ServerInstance) Init(dKeyNfsData []byte, xor uint32, minutes time.Durat
time.Sleep(time.Minute)
now := time.Now()
i.Lock()
for index, session := range i.sessions {
for ticket, session := range i.sessions {
if now.After(session.expire) {
delete(i.sessions, index)
delete(i.sessions, ticket)
}
}
i.Unlock()
@ -68,11 +72,11 @@ func (i *ServerInstance) Init(dKeyNfsData []byte, xor uint32, minutes time.Durat
}
func (i *ServerInstance) Handshake(conn net.Conn) (net.Conn, error) {
if i.dKeyNfs == nil {
if i.nfsDKey == nil {
return nil, errors.New("uninitialized")
}
if i.xor == 1 {
conn = NewXorConn(conn, i.dKeyNfs.EncapsulationKey().Bytes())
if i.xor > 0 {
conn = NewXorConn(conn, i.nfsEKeyBytes)
}
c := &ServerConn{Conn: conn}
@ -100,49 +104,50 @@ func (i *ServerInstance) Handshake(conn net.Conn) (net.Conn, error) {
return nil, err
}
if l, _ := decodeHeader(peerHeader); l != 0 {
c.Conn.Write(make([]byte, crypto.RandBetween(100, 1000))) // make client do new handshake
noise := make([]byte, crypto.RandBetween(100, 1000))
rand.Read(noise)
c.Conn.Write(noise) // make client do new handshake
return nil, errors.New("invalid ticket")
}
peerClientHello := make([]byte, 1088+1184+1)
peerClientHello := make([]byte, 1+1184+1088)
copy(peerClientHello, peerTicketHello)
copy(peerClientHello[53:], peerHeader)
if _, err := io.ReadFull(c.Conn, peerClientHello[58:]); err != nil {
return nil, err
}
encapsulatedNfsKey := peerClientHello[:1088]
eKeyPfsData := peerClientHello[1088:2272]
c.cipher = peerClientHello[2272]
if c.cipher != 0 && c.cipher != 1 {
return nil, errors.New("invalid cipher")
}
c.cipher = peerClientHello[0]
pfsEKeyBytes := peerClientHello[1:1185]
encapsulatedNfsKey := peerClientHello[1185:2273]
nfsKey, err := i.dKeyNfs.Decapsulate(encapsulatedNfsKey)
pfsEKey, err := mlkem.NewEncapsulationKey768(pfsEKeyBytes)
if err != nil {
return nil, err
}
eKeyPfs, err := mlkem.NewEncapsulationKey768(eKeyPfsData)
nfsKey, err := i.nfsDKey.Decapsulate(encapsulatedNfsKey)
if err != nil {
return nil, err
}
pfsKey, encapsulatedPfsKey := eKeyPfs.Encapsulate()
c.baseKey = append(nfsKey, pfsKey...)
pfsKey, encapsulatedPfsKey := pfsEKey.Encapsulate()
c.baseKey = append(pfsKey, nfsKey...)
authKey := make([]byte, 32)
hkdf.New(sha256.New, c.baseKey, encapsulatedNfsKey, eKeyPfsData).Read(authKey)
nonce := make([]byte, 12)
c.ticket = newAead(c.cipher, authKey).Seal(nil, nonce, []byte("VLESS"), encapsulatedPfsKey)
hkdf.New(sha256.New, c.baseKey, encapsulatedPfsKey, encapsulatedNfsKey).Read(authKey)
nonce := [12]byte{c.cipher}
c.ticket = newAead(c.cipher, authKey).Seal(nil, nonce[:], []byte("VLESS"), pfsEKeyBytes)
padding := crypto.RandBetween(100, 1000)
paddingLen := crypto.RandBetween(100, 1000)
serverHello := make([]byte, 1088+21+5+padding)
serverHello := make([]byte, 1088+21+5+paddingLen)
copy(serverHello, encapsulatedPfsKey)
copy(serverHello[1088:], c.ticket)
encodeHeader(serverHello[1109:], int(padding))
encodeHeader(serverHello[1109:], int(paddingLen))
rand.Read(serverHello[1114:])
if _, err := c.Conn.Write(serverHello); err != nil {
return nil, err
}
// we can send more padding if needed
if i.minutes > 0 {
i.Lock()
@ -168,11 +173,11 @@ func (c *ServerConn) Read(b []byte) (int, error) {
if _, err := io.ReadFull(c.Conn, peerHeader); err != nil {
return 0, err
}
peerPadding, _ := decodeHeader(peerHeader)
if peerPadding == 0 {
peerPaddingLen, _ := decodeHeader(peerHeader)
if peerPaddingLen == 0 {
break
}
if _, err := io.ReadFull(c.Conn, make([]byte, peerPadding)); err != nil {
if _, err := io.ReadFull(c.Conn, make([]byte, peerPaddingLen)); err != nil {
return 0, err
}
}
@ -212,7 +217,7 @@ func (c *ServerConn) Read(b []byte) (int, error) {
}
dst := peerData[:peerLength-16]
if len(dst) <= len(b) {
dst = b[:len(dst)] // max=8192 is recommended for peer
dst = b[:len(dst)] // avoids another copy()
}
_, err = c.peerAead.Open(dst[:0], c.peerNonce, peerData, peerHeader)
increaseNonce(c.peerNonce)
@ -226,14 +231,20 @@ func (c *ServerConn) Read(b []byte) (int, error) {
return len(dst), nil
}
func (c *ServerConn) Write(b []byte) (int, error) { // after first Read()
func (c *ServerConn) Write(b []byte) (int, error) {
if len(b) == 0 {
return 0, nil
}
for n := 0; n < len(b); {
b := b[n:]
if len(b) > 8192 {
b = b[:8192] // for avoiding another copy() in client's Read()
}
n += len(b)
var data []byte
if c.aead == nil {
if c.peerRandom == nil {
return 0, errors.New("can not Write() first")
return 0, errors.New("empty c.peerRandom")
}
data = make([]byte, 32+5+len(b)+16)
rand.Read(data[:32])
@ -252,5 +263,6 @@ func (c *ServerConn) Write(b []byte) (int, error) { // after first Read()
if _, err := c.Conn.Write(data); err != nil {
return 0, err
}
}
return len(b), nil
}

2
proxy/vless/encryption/xor.go
View File

@ -38,7 +38,7 @@ func (c *XorConn) Write(b []byte) (int, error) {
return 0, err
}
if iv != nil {
b = b[16:]
b = b[16:] // for len(b)
}
return len(b), nil
}