package encoding import ( "crypto/aes" "crypto/cipher" "crypto/md5" "hash/fnv" "io" "sync" "time" "v2ray.com/core/common/dice" "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/net" "v2ray.com/core/common/protocol" "v2ray.com/core/common/serial" "v2ray.com/core/common/signal" "v2ray.com/core/proxy/vmess" ) type sessionId struct { user [16]byte key [16]byte nonce [16]byte } type SessionHistory struct { sync.RWMutex cache map[sessionId]time.Time task *signal.PeriodicTask } func NewSessionHistory() *SessionHistory { h := &SessionHistory{ cache: make(map[sessionId]time.Time, 128), } h.task = &signal.PeriodicTask{ Interval: time.Second * 30, Execute: func() error { h.removeExpiredEntries() return nil }, } common.Must(h.task.Start()) return h } // Close implements common.Closable. func (h *SessionHistory) Close() error { return h.task.Close() } func (h *SessionHistory) addIfNotExits(session sessionId) bool { h.Lock() defer h.Unlock() if expire, found := h.cache[session]; found && expire.After(time.Now()) { return false } h.cache[session] = time.Now().Add(time.Minute * 3) return true } func (h *SessionHistory) removeExpiredEntries() { now := time.Now() h.Lock() defer h.Unlock() for session, expire := range h.cache { if expire.Before(now) { delete(h.cache, session) } } } type ServerSession struct { userValidator protocol.UserValidator sessionHistory *SessionHistory requestBodyKey []byte requestBodyIV []byte responseBodyKey []byte responseBodyIV []byte responseHeader byte responseWriter io.Writer } // NewServerSession creates a new ServerSession, using the given UserValidator. // The ServerSession instance doesn't take ownership of the validator. func NewServerSession(validator protocol.UserValidator, 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 } func (s *ServerSession) DecodeRequestHeader(reader io.Reader) (*protocol.RequestHeader, error) { buffer := buf.New() defer buffer.Release() if err := buffer.AppendSupplier(buf.ReadFullFrom(reader, protocol.IDBytesLen)); err != nil { return nil, newError("failed to read request header").Base(err) } user, timestamp, valid := s.userValidator.Get(buffer.Bytes()) if !valid { return nil, newError("invalid user") } timestampHash := md5.New() common.Must2(timestampHash.Write(hashTimestamp(timestamp))) iv := timestampHash.Sum(nil) account, err := user.GetTypedAccount() if err != nil { return nil, newError("failed to get user account").Base(err) } vmessAccount := account.(*vmess.InternalAccount) aesStream := crypto.NewAesDecryptionStream(vmessAccount.ID.CmdKey(), iv) decryptor := crypto.NewCryptionReader(aesStream, reader) if err := buffer.Reset(buf.ReadFullFrom(decryptor, 38)); err != nil { return nil, newError("failed to read request header").Base(err) } request := &protocol.RequestHeader{ User: user, Version: buffer.Byte(0), } s.requestBodyIV = append([]byte(nil), buffer.BytesRange(1, 17)...) // 16 bytes s.requestBodyKey = append([]byte(nil), buffer.BytesRange(17, 33)...) // 16 bytes var sid sessionId copy(sid.user[:], vmessAccount.ID.Bytes()) copy(sid.key[:], s.requestBodyKey) copy(sid.nonce[:], s.requestBodyIV) if !s.sessionHistory.addIfNotExits(sid) { return nil, newError("duplicated session id, possibly under replay attack") } 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)) var invalidRequestErr error defer func() { if invalidRequestErr != nil { randomLen := dice.Roll(64) + 1 // Read random number of bytes for prevent detection. buffer.AppendSupplier(buf.ReadFullFrom(decryptor, randomLen)) } }() if request.Security == protocol.SecurityType_UNKNOWN || request.Security == protocol.SecurityType_AUTO { invalidRequestErr = newError("unknown security type") return nil, invalidRequestErr } 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 } else { invalidRequestErr = newError("invalid address").Base(err) return nil, invalidRequestErr } default: invalidRequestErr = newError("invalid request command: ", request.Command) return nil, invalidRequestErr } if padingLen > 0 { if err := buffer.AppendSupplier(buf.ReadFullFrom(decryptor, padingLen)); err != nil { return nil, newError("failed to read padding").Base(err) } } if err := buffer.AppendSupplier(buf.ReadFullFrom(decryptor, 4)); err != nil { return nil, newError("failed to read checksum").Base(err) } fnv1a := fnv.New32a() common.Must2(fnv1a.Write(buffer.BytesTo(-4))) actualHash := fnv1a.Sum32() expectedHash := serial.BytesToUint32(buffer.BytesFrom(-4)) if actualHash != expectedHash { return nil, newError("invalid auth") } if request.Address == nil { return nil, newError("invalid remote address") } return request, nil } 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) } 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.NoOpBytesGenerator{}, AdditionalDataGenerator: crypto.NoOpBytesGenerator{}, } return crypto.NewAuthenticationReader(auth, sizeParser, reader, protocol.TransferTypePacket) } 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.NoOpBytesGenerator{}, AdditionalDataGenerator: crypto.NoOpBytesGenerator{}, } return crypto.NewAuthenticationReader(auth, sizeParser, cryptionReader, request.Command.TransferType()) } return buf.NewReader(cryptionReader) case protocol.SecurityType_AES128_GCM: block, _ := aes.NewCipher(s.requestBodyKey) aead, _ := cipher.NewGCM(block) auth := &crypto.AEADAuthenticator{ AEAD: aead, NonceGenerator: &ChunkNonceGenerator{ Nonce: append([]byte(nil), s.requestBodyIV...), Size: aead.NonceSize(), }, AdditionalDataGenerator: crypto.NoOpBytesGenerator{}, } return crypto.NewAuthenticationReader(auth, sizeParser, reader, request.Command.TransferType()) case protocol.SecurityType_CHACHA20_POLY1305: aead, _ := chacha20poly1305.New(GenerateChacha20Poly1305Key(s.requestBodyKey)) auth := &crypto.AEADAuthenticator{ AEAD: aead, NonceGenerator: &ChunkNonceGenerator{ Nonce: append([]byte(nil), s.requestBodyIV...), Size: aead.NonceSize(), }, AdditionalDataGenerator: crypto.NoOpBytesGenerator{}, } return crypto.NewAuthenticationReader(auth, sizeParser, reader, request.Command.TransferType()) default: panic("Unknown security type.") } } func (s *ServerSession) EncodeResponseHeader(header *protocol.ResponseHeader, writer io.Writer) { responseBodyKey := md5.Sum(s.requestBodyKey) responseBodyIV := md5.Sum(s.requestBodyIV) s.responseBodyKey = responseBodyKey[:] s.responseBodyIV = responseBodyIV[:] aesStream := crypto.NewAesEncryptionStream(s.responseBodyKey, s.responseBodyIV) encryptionWriter := crypto.NewCryptionWriter(aesStream, writer) s.responseWriter = encryptionWriter 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})) } } 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) } 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.NoOpBytesGenerator{}, AdditionalDataGenerator: crypto.NoOpBytesGenerator{}, } return crypto.NewAuthenticationWriter(auth, sizeParser, writer, protocol.TransferTypePacket) } return buf.NewWriter(writer) case protocol.SecurityType_LEGACY: if request.Option.Has(protocol.RequestOptionChunkStream) { auth := &crypto.AEADAuthenticator{ AEAD: new(FnvAuthenticator), NonceGenerator: crypto.NoOpBytesGenerator{}, AdditionalDataGenerator: crypto.NoOpBytesGenerator{}, } return crypto.NewAuthenticationWriter(auth, sizeParser, s.responseWriter, request.Command.TransferType()) } return buf.NewWriter(s.responseWriter) case protocol.SecurityType_AES128_GCM: block, _ := aes.NewCipher(s.responseBodyKey) aead, _ := cipher.NewGCM(block) auth := &crypto.AEADAuthenticator{ AEAD: aead, NonceGenerator: &ChunkNonceGenerator{ Nonce: append([]byte(nil), s.responseBodyIV...), Size: aead.NonceSize(), }, AdditionalDataGenerator: crypto.NoOpBytesGenerator{}, } return crypto.NewAuthenticationWriter(auth, sizeParser, writer, request.Command.TransferType()) case protocol.SecurityType_CHACHA20_POLY1305: aead, _ := chacha20poly1305.New(GenerateChacha20Poly1305Key(s.responseBodyKey)) auth := &crypto.AEADAuthenticator{ AEAD: aead, NonceGenerator: &ChunkNonceGenerator{ Nonce: append([]byte(nil), s.responseBodyIV...), Size: aead.NonceSize(), }, AdditionalDataGenerator: crypto.NoOpBytesGenerator{}, } return crypto.NewAuthenticationWriter(auth, sizeParser, writer, request.Command.TransferType()) default: panic("Unknown security type.") } }