mirror of
https://github.com/v2fly/v2ray-core.git
synced 2024-12-21 17:46:58 -05:00
490 lines
17 KiB
Go
490 lines
17 KiB
Go
package encoding
|
|
|
|
import (
|
|
"bytes"
|
|
"crypto/aes"
|
|
"crypto/cipher"
|
|
"crypto/md5"
|
|
"crypto/sha256"
|
|
"encoding/binary"
|
|
"hash/fnv"
|
|
"io"
|
|
"io/ioutil"
|
|
"sync"
|
|
"time"
|
|
|
|
"golang.org/x/crypto/chacha20poly1305"
|
|
"v2ray.com/core/common"
|
|
"v2ray.com/core/common/bitmask"
|
|
"v2ray.com/core/common/buf"
|
|
"v2ray.com/core/common/crypto"
|
|
"v2ray.com/core/common/dice"
|
|
"v2ray.com/core/common/net"
|
|
"v2ray.com/core/common/protocol"
|
|
"v2ray.com/core/common/task"
|
|
"v2ray.com/core/proxy/vmess"
|
|
vmessaead "v2ray.com/core/proxy/vmess/aead"
|
|
)
|
|
|
|
type sessionId struct {
|
|
user [16]byte
|
|
key [16]byte
|
|
nonce [16]byte
|
|
}
|
|
|
|
// SessionHistory keeps track of historical session ids, to prevent replay attacks.
|
|
type SessionHistory struct {
|
|
sync.RWMutex
|
|
cache map[sessionId]time.Time
|
|
task *task.Periodic
|
|
}
|
|
|
|
// NewSessionHistory creates a new SessionHistory object.
|
|
func NewSessionHistory() *SessionHistory {
|
|
h := &SessionHistory{
|
|
cache: make(map[sessionId]time.Time, 128),
|
|
}
|
|
h.task = &task.Periodic{
|
|
Interval: time.Second * 30,
|
|
Execute: h.removeExpiredEntries,
|
|
}
|
|
return h
|
|
}
|
|
|
|
// Close implements common.Closable.
|
|
func (h *SessionHistory) Close() error {
|
|
return h.task.Close()
|
|
}
|
|
|
|
func (h *SessionHistory) addIfNotExits(session sessionId) bool {
|
|
h.Lock()
|
|
|
|
if expire, found := h.cache[session]; found && expire.After(time.Now()) {
|
|
h.Unlock()
|
|
return false
|
|
}
|
|
|
|
h.cache[session] = time.Now().Add(time.Minute * 3)
|
|
h.Unlock()
|
|
common.Must(h.task.Start())
|
|
return true
|
|
}
|
|
|
|
func (h *SessionHistory) removeExpiredEntries() error {
|
|
now := time.Now()
|
|
|
|
h.Lock()
|
|
defer h.Unlock()
|
|
|
|
if len(h.cache) == 0 {
|
|
return newError("nothing to do")
|
|
}
|
|
|
|
for session, expire := range h.cache {
|
|
if expire.Before(now) {
|
|
delete(h.cache, session)
|
|
}
|
|
}
|
|
|
|
if len(h.cache) == 0 {
|
|
h.cache = make(map[sessionId]time.Time, 128)
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// ServerSession keeps information for a session in VMess server.
|
|
type ServerSession struct {
|
|
userValidator *vmess.TimedUserValidator
|
|
sessionHistory *SessionHistory
|
|
requestBodyKey [16]byte
|
|
requestBodyIV [16]byte
|
|
responseBodyKey [16]byte
|
|
responseBodyIV [16]byte
|
|
responseWriter io.Writer
|
|
responseHeader byte
|
|
|
|
isAEADRequest bool
|
|
|
|
isAEADForced bool
|
|
}
|
|
|
|
// NewServerSession creates a new ServerSession, using the given UserValidator.
|
|
// The ServerSession instance doesn't take ownership of the validator.
|
|
func NewServerSession(validator *vmess.TimedUserValidator, sessionHistory *SessionHistory) *ServerSession {
|
|
return &ServerSession{
|
|
userValidator: validator,
|
|
sessionHistory: sessionHistory,
|
|
}
|
|
}
|
|
|
|
func parseSecurityType(b byte) protocol.SecurityType {
|
|
if _, f := protocol.SecurityType_name[int32(b)]; f {
|
|
st := protocol.SecurityType(b)
|
|
// For backward compatibility.
|
|
if st == protocol.SecurityType_UNKNOWN {
|
|
st = protocol.SecurityType_LEGACY
|
|
}
|
|
return st
|
|
}
|
|
return protocol.SecurityType_UNKNOWN
|
|
}
|
|
|
|
// DecodeRequestHeader decodes and returns (if successful) a RequestHeader from an input stream.
|
|
func (s *ServerSession) DecodeRequestHeader(reader io.Reader) (*protocol.RequestHeader, error) {
|
|
buffer := buf.New()
|
|
behaviorRand := dice.NewDeterministicDice(int64(s.userValidator.GetBehaviorSeed()))
|
|
BaseDrainSize := behaviorRand.Roll(3266)
|
|
RandDrainMax := behaviorRand.Roll(64) + 1
|
|
RandDrainRolled := dice.Roll(RandDrainMax)
|
|
DrainSize := BaseDrainSize + 16 + 38 + RandDrainRolled
|
|
readSizeRemain := DrainSize
|
|
|
|
drainConnection := func(e error) error {
|
|
//We read a deterministic generated length of data before closing the connection to offset padding read pattern
|
|
readSizeRemain -= int(buffer.Len())
|
|
if readSizeRemain > 0 {
|
|
err := s.DrainConnN(reader, readSizeRemain)
|
|
if err != nil {
|
|
return newError("failed to drain connection DrainSize = ", BaseDrainSize, " ", RandDrainMax, " ", RandDrainRolled).Base(err).Base(e)
|
|
}
|
|
return newError("connection drained DrainSize = ", BaseDrainSize, " ", RandDrainMax, " ", RandDrainRolled).Base(e)
|
|
}
|
|
return e
|
|
}
|
|
|
|
defer func() {
|
|
buffer.Release()
|
|
}()
|
|
|
|
if _, err := buffer.ReadFullFrom(reader, protocol.IDBytesLen); err != nil {
|
|
return nil, newError("failed to read request header").Base(err)
|
|
}
|
|
|
|
var decryptor io.Reader
|
|
var vmessAccount *vmess.MemoryAccount
|
|
|
|
user, foundAEAD, errorAEAD := s.userValidator.GetAEAD(buffer.Bytes())
|
|
|
|
var fixedSizeAuthID [16]byte
|
|
copy(fixedSizeAuthID[:], buffer.Bytes())
|
|
|
|
if foundAEAD {
|
|
vmessAccount = user.Account.(*vmess.MemoryAccount)
|
|
var fixedSizeCmdKey [16]byte
|
|
copy(fixedSizeCmdKey[:], vmessAccount.ID.CmdKey())
|
|
aeadData, shouldDrain, errorReason, bytesRead := vmessaead.OpenVMessAEADHeader(fixedSizeCmdKey, fixedSizeAuthID, reader)
|
|
if errorReason != nil {
|
|
if shouldDrain {
|
|
readSizeRemain -= bytesRead
|
|
return nil, drainConnection(newError("AEAD read failed").Base(errorReason))
|
|
} else {
|
|
return nil, drainConnection(newError("AEAD read failed, drain skiped").Base(errorReason))
|
|
}
|
|
}
|
|
decryptor = bytes.NewReader(aeadData)
|
|
s.isAEADRequest = true
|
|
} else if !s.isAEADForced && errorAEAD == vmessaead.ErrNotFound {
|
|
userLegacy, timestamp, valid, userValidationError := s.userValidator.Get(buffer.Bytes())
|
|
if !valid || userValidationError != nil {
|
|
return nil, drainConnection(newError("invalid user").Base(userValidationError))
|
|
}
|
|
user = userLegacy
|
|
iv := hashTimestamp(md5.New(), timestamp)
|
|
vmessAccount = userLegacy.Account.(*vmess.MemoryAccount)
|
|
|
|
aesStream := crypto.NewAesDecryptionStream(vmessAccount.ID.CmdKey(), iv[:])
|
|
decryptor = crypto.NewCryptionReader(aesStream, reader)
|
|
} else {
|
|
return nil, drainConnection(newError("invalid user").Base(errorAEAD))
|
|
}
|
|
|
|
readSizeRemain -= int(buffer.Len())
|
|
buffer.Clear()
|
|
if _, err := buffer.ReadFullFrom(decryptor, 38); err != nil {
|
|
return nil, newError("failed to read request header").Base(err)
|
|
}
|
|
|
|
request := &protocol.RequestHeader{
|
|
User: user,
|
|
Version: buffer.Byte(0),
|
|
}
|
|
|
|
copy(s.requestBodyIV[:], buffer.BytesRange(1, 17)) // 16 bytes
|
|
copy(s.requestBodyKey[:], buffer.BytesRange(17, 33)) // 16 bytes
|
|
var sid sessionId
|
|
copy(sid.user[:], vmessAccount.ID.Bytes())
|
|
sid.key = s.requestBodyKey
|
|
sid.nonce = s.requestBodyIV
|
|
if !s.sessionHistory.addIfNotExits(sid) {
|
|
if !s.isAEADRequest {
|
|
drainErr := s.userValidator.BurnTaintFuse(fixedSizeAuthID[:])
|
|
if drainErr != nil {
|
|
return nil, drainConnection(newError("duplicated session id, possibly under replay attack, and failed to taint userHash").Base(drainErr))
|
|
}
|
|
return nil, drainConnection(newError("duplicated session id, possibly under replay attack, userHash tainted"))
|
|
} else {
|
|
return nil, newError("duplicated session id, possibly under replay attack, but this is a AEAD request")
|
|
}
|
|
|
|
}
|
|
|
|
s.responseHeader = buffer.Byte(33) // 1 byte
|
|
request.Option = bitmask.Byte(buffer.Byte(34)) // 1 byte
|
|
padingLen := int(buffer.Byte(35) >> 4)
|
|
request.Security = parseSecurityType(buffer.Byte(35) & 0x0F)
|
|
// 1 bytes reserved
|
|
request.Command = protocol.RequestCommand(buffer.Byte(37))
|
|
|
|
switch request.Command {
|
|
case protocol.RequestCommandMux:
|
|
request.Address = net.DomainAddress("v1.mux.cool")
|
|
request.Port = 0
|
|
case protocol.RequestCommandTCP, protocol.RequestCommandUDP:
|
|
if addr, port, err := addrParser.ReadAddressPort(buffer, decryptor); err == nil {
|
|
request.Address = addr
|
|
request.Port = port
|
|
}
|
|
}
|
|
|
|
if padingLen > 0 {
|
|
if _, err := buffer.ReadFullFrom(decryptor, int32(padingLen)); err != nil {
|
|
if !s.isAEADRequest {
|
|
burnErr := s.userValidator.BurnTaintFuse(fixedSizeAuthID[:])
|
|
if burnErr != nil {
|
|
return nil, newError("failed to read padding, failed to taint userHash").Base(burnErr).Base(err)
|
|
}
|
|
return nil, newError("failed to read padding, userHash tainted").Base(err)
|
|
}
|
|
return nil, newError("failed to read padding").Base(err)
|
|
}
|
|
}
|
|
|
|
if _, err := buffer.ReadFullFrom(decryptor, 4); err != nil {
|
|
if !s.isAEADRequest {
|
|
burnErr := s.userValidator.BurnTaintFuse(fixedSizeAuthID[:])
|
|
if burnErr != nil {
|
|
return nil, newError("failed to read checksum, failed to taint userHash").Base(burnErr).Base(err)
|
|
}
|
|
return nil, newError("failed to read checksum, userHash tainted").Base(err)
|
|
}
|
|
return nil, newError("failed to read checksum").Base(err)
|
|
}
|
|
|
|
fnv1a := fnv.New32a()
|
|
common.Must2(fnv1a.Write(buffer.BytesTo(-4)))
|
|
actualHash := fnv1a.Sum32()
|
|
expectedHash := binary.BigEndian.Uint32(buffer.BytesFrom(-4))
|
|
|
|
if actualHash != expectedHash {
|
|
if !s.isAEADRequest {
|
|
Autherr := newError("invalid auth, legacy userHash tainted")
|
|
burnErr := s.userValidator.BurnTaintFuse(fixedSizeAuthID[:])
|
|
if burnErr != nil {
|
|
Autherr = newError("invalid auth, can't taint legacy userHash").Base(burnErr)
|
|
}
|
|
//It is possible that we are under attack described in https://github.com/v2ray/v2ray-core/issues/2523
|
|
return nil, drainConnection(Autherr)
|
|
} else {
|
|
return nil, newError("invalid auth, but this is a AEAD request")
|
|
}
|
|
|
|
}
|
|
|
|
if request.Address == nil {
|
|
return nil, newError("invalid remote address")
|
|
}
|
|
|
|
if request.Security == protocol.SecurityType_UNKNOWN || request.Security == protocol.SecurityType_AUTO {
|
|
return nil, newError("unknown security type: ", request.Security)
|
|
}
|
|
|
|
return request, nil
|
|
}
|
|
|
|
// DecodeRequestBody returns Reader from which caller can fetch decrypted body.
|
|
func (s *ServerSession) DecodeRequestBody(request *protocol.RequestHeader, reader io.Reader) buf.Reader {
|
|
var sizeParser crypto.ChunkSizeDecoder = crypto.PlainChunkSizeParser{}
|
|
if request.Option.Has(protocol.RequestOptionChunkMasking) {
|
|
sizeParser = NewShakeSizeParser(s.requestBodyIV[:])
|
|
}
|
|
var padding crypto.PaddingLengthGenerator
|
|
if request.Option.Has(protocol.RequestOptionGlobalPadding) {
|
|
padding = sizeParser.(crypto.PaddingLengthGenerator)
|
|
}
|
|
|
|
switch request.Security {
|
|
case protocol.SecurityType_NONE:
|
|
if request.Option.Has(protocol.RequestOptionChunkStream) {
|
|
if request.Command.TransferType() == protocol.TransferTypeStream {
|
|
return crypto.NewChunkStreamReader(sizeParser, reader)
|
|
}
|
|
|
|
auth := &crypto.AEADAuthenticator{
|
|
AEAD: new(NoOpAuthenticator),
|
|
NonceGenerator: crypto.GenerateEmptyBytes(),
|
|
AdditionalDataGenerator: crypto.GenerateEmptyBytes(),
|
|
}
|
|
return crypto.NewAuthenticationReader(auth, sizeParser, reader, protocol.TransferTypePacket, padding)
|
|
}
|
|
|
|
return buf.NewReader(reader)
|
|
case protocol.SecurityType_LEGACY:
|
|
aesStream := crypto.NewAesDecryptionStream(s.requestBodyKey[:], s.requestBodyIV[:])
|
|
cryptionReader := crypto.NewCryptionReader(aesStream, reader)
|
|
if request.Option.Has(protocol.RequestOptionChunkStream) {
|
|
auth := &crypto.AEADAuthenticator{
|
|
AEAD: new(FnvAuthenticator),
|
|
NonceGenerator: crypto.GenerateEmptyBytes(),
|
|
AdditionalDataGenerator: crypto.GenerateEmptyBytes(),
|
|
}
|
|
return crypto.NewAuthenticationReader(auth, sizeParser, cryptionReader, request.Command.TransferType(), padding)
|
|
}
|
|
|
|
return buf.NewReader(cryptionReader)
|
|
case protocol.SecurityType_AES128_GCM:
|
|
aead := crypto.NewAesGcm(s.requestBodyKey[:])
|
|
|
|
auth := &crypto.AEADAuthenticator{
|
|
AEAD: aead,
|
|
NonceGenerator: GenerateChunkNonce(s.requestBodyIV[:], uint32(aead.NonceSize())),
|
|
AdditionalDataGenerator: crypto.GenerateEmptyBytes(),
|
|
}
|
|
return crypto.NewAuthenticationReader(auth, sizeParser, reader, request.Command.TransferType(), padding)
|
|
case protocol.SecurityType_CHACHA20_POLY1305:
|
|
aead, _ := chacha20poly1305.New(GenerateChacha20Poly1305Key(s.requestBodyKey[:]))
|
|
|
|
auth := &crypto.AEADAuthenticator{
|
|
AEAD: aead,
|
|
NonceGenerator: GenerateChunkNonce(s.requestBodyIV[:], uint32(aead.NonceSize())),
|
|
AdditionalDataGenerator: crypto.GenerateEmptyBytes(),
|
|
}
|
|
return crypto.NewAuthenticationReader(auth, sizeParser, reader, request.Command.TransferType(), padding)
|
|
default:
|
|
panic("Unknown security type.")
|
|
}
|
|
}
|
|
|
|
// EncodeResponseHeader writes encoded response header into the given writer.
|
|
func (s *ServerSession) EncodeResponseHeader(header *protocol.ResponseHeader, writer io.Writer) {
|
|
var encryptionWriter io.Writer
|
|
if !s.isAEADRequest {
|
|
s.responseBodyKey = md5.Sum(s.requestBodyKey[:])
|
|
s.responseBodyIV = md5.Sum(s.requestBodyIV[:])
|
|
} else {
|
|
BodyKey := sha256.Sum256(s.requestBodyKey[:])
|
|
copy(s.responseBodyKey[:], BodyKey[:16])
|
|
BodyIV := sha256.Sum256(s.requestBodyIV[:])
|
|
copy(s.responseBodyIV[:], BodyIV[:16])
|
|
}
|
|
|
|
aesStream := crypto.NewAesEncryptionStream(s.responseBodyKey[:], s.responseBodyIV[:])
|
|
encryptionWriter = crypto.NewCryptionWriter(aesStream, writer)
|
|
s.responseWriter = encryptionWriter
|
|
|
|
aeadEncryptedHeaderBuffer := bytes.NewBuffer(nil)
|
|
|
|
if s.isAEADRequest {
|
|
encryptionWriter = aeadEncryptedHeaderBuffer
|
|
}
|
|
|
|
common.Must2(encryptionWriter.Write([]byte{s.responseHeader, byte(header.Option)}))
|
|
err := MarshalCommand(header.Command, encryptionWriter)
|
|
if err != nil {
|
|
common.Must2(encryptionWriter.Write([]byte{0x00, 0x00}))
|
|
}
|
|
|
|
if s.isAEADRequest {
|
|
|
|
aeadResponseHeaderLengthEncryptionKey := vmessaead.KDF16(s.responseBodyKey[:], vmessaead.KDFSaltConst_AEADRespHeaderLenKey)
|
|
aeadResponseHeaderLengthEncryptionIV := vmessaead.KDF(s.responseBodyIV[:], vmessaead.KDFSaltConst_AEADRespHeaderLenIV)[:12]
|
|
|
|
aeadResponseHeaderLengthEncryptionKeyAESBlock := common.Must2(aes.NewCipher(aeadResponseHeaderLengthEncryptionKey)).(cipher.Block)
|
|
aeadResponseHeaderLengthEncryptionAEAD := common.Must2(cipher.NewGCM(aeadResponseHeaderLengthEncryptionKeyAESBlock)).(cipher.AEAD)
|
|
|
|
aeadResponseHeaderLengthEncryptionBuffer := bytes.NewBuffer(nil)
|
|
|
|
decryptedResponseHeaderLengthBinaryDeserializeBuffer := uint16(aeadEncryptedHeaderBuffer.Len())
|
|
|
|
common.Must(binary.Write(aeadResponseHeaderLengthEncryptionBuffer, binary.BigEndian, decryptedResponseHeaderLengthBinaryDeserializeBuffer))
|
|
|
|
AEADEncryptedLength := aeadResponseHeaderLengthEncryptionAEAD.Seal(nil, aeadResponseHeaderLengthEncryptionIV, aeadResponseHeaderLengthEncryptionBuffer.Bytes(), nil)
|
|
common.Must2(io.Copy(writer, bytes.NewReader(AEADEncryptedLength)))
|
|
|
|
aeadResponseHeaderPayloadEncryptionKey := vmessaead.KDF16(s.responseBodyKey[:], vmessaead.KDFSaltConst_AEADRespHeaderPayloadKey)
|
|
aeadResponseHeaderPayloadEncryptionIV := vmessaead.KDF(s.responseBodyIV[:], vmessaead.KDFSaltConst_AEADRespHeaderPayloadIV)[:12]
|
|
|
|
aeadResponseHeaderPayloadEncryptionKeyAESBlock := common.Must2(aes.NewCipher(aeadResponseHeaderPayloadEncryptionKey)).(cipher.Block)
|
|
aeadResponseHeaderPayloadEncryptionAEAD := common.Must2(cipher.NewGCM(aeadResponseHeaderPayloadEncryptionKeyAESBlock)).(cipher.AEAD)
|
|
|
|
aeadEncryptedHeaderPayload := aeadResponseHeaderPayloadEncryptionAEAD.Seal(nil, aeadResponseHeaderPayloadEncryptionIV, aeadEncryptedHeaderBuffer.Bytes(), nil)
|
|
common.Must2(io.Copy(writer, bytes.NewReader(aeadEncryptedHeaderPayload)))
|
|
}
|
|
}
|
|
|
|
// EncodeResponseBody returns a Writer that auto-encrypt content written by caller.
|
|
func (s *ServerSession) EncodeResponseBody(request *protocol.RequestHeader, writer io.Writer) buf.Writer {
|
|
var sizeParser crypto.ChunkSizeEncoder = crypto.PlainChunkSizeParser{}
|
|
if request.Option.Has(protocol.RequestOptionChunkMasking) {
|
|
sizeParser = NewShakeSizeParser(s.responseBodyIV[:])
|
|
}
|
|
var padding crypto.PaddingLengthGenerator
|
|
if request.Option.Has(protocol.RequestOptionGlobalPadding) {
|
|
padding = sizeParser.(crypto.PaddingLengthGenerator)
|
|
}
|
|
|
|
switch request.Security {
|
|
case protocol.SecurityType_NONE:
|
|
if request.Option.Has(protocol.RequestOptionChunkStream) {
|
|
if request.Command.TransferType() == protocol.TransferTypeStream {
|
|
return crypto.NewChunkStreamWriter(sizeParser, writer)
|
|
}
|
|
|
|
auth := &crypto.AEADAuthenticator{
|
|
AEAD: new(NoOpAuthenticator),
|
|
NonceGenerator: crypto.GenerateEmptyBytes(),
|
|
AdditionalDataGenerator: crypto.GenerateEmptyBytes(),
|
|
}
|
|
return crypto.NewAuthenticationWriter(auth, sizeParser, writer, protocol.TransferTypePacket, padding)
|
|
}
|
|
|
|
return buf.NewWriter(writer)
|
|
case protocol.SecurityType_LEGACY:
|
|
if request.Option.Has(protocol.RequestOptionChunkStream) {
|
|
auth := &crypto.AEADAuthenticator{
|
|
AEAD: new(FnvAuthenticator),
|
|
NonceGenerator: crypto.GenerateEmptyBytes(),
|
|
AdditionalDataGenerator: crypto.GenerateEmptyBytes(),
|
|
}
|
|
return crypto.NewAuthenticationWriter(auth, sizeParser, s.responseWriter, request.Command.TransferType(), padding)
|
|
}
|
|
|
|
return &buf.SequentialWriter{Writer: s.responseWriter}
|
|
case protocol.SecurityType_AES128_GCM:
|
|
aead := crypto.NewAesGcm(s.responseBodyKey[:])
|
|
|
|
auth := &crypto.AEADAuthenticator{
|
|
AEAD: aead,
|
|
NonceGenerator: GenerateChunkNonce(s.responseBodyIV[:], uint32(aead.NonceSize())),
|
|
AdditionalDataGenerator: crypto.GenerateEmptyBytes(),
|
|
}
|
|
return crypto.NewAuthenticationWriter(auth, sizeParser, writer, request.Command.TransferType(), padding)
|
|
case protocol.SecurityType_CHACHA20_POLY1305:
|
|
aead, _ := chacha20poly1305.New(GenerateChacha20Poly1305Key(s.responseBodyKey[:]))
|
|
|
|
auth := &crypto.AEADAuthenticator{
|
|
AEAD: aead,
|
|
NonceGenerator: GenerateChunkNonce(s.responseBodyIV[:], uint32(aead.NonceSize())),
|
|
AdditionalDataGenerator: crypto.GenerateEmptyBytes(),
|
|
}
|
|
return crypto.NewAuthenticationWriter(auth, sizeParser, writer, request.Command.TransferType(), padding)
|
|
default:
|
|
panic("Unknown security type.")
|
|
}
|
|
}
|
|
|
|
func (s *ServerSession) DrainConnN(reader io.Reader, n int) error {
|
|
_, err := io.CopyN(ioutil.Discard, reader, int64(n))
|
|
return err
|
|
}
|