package encoding import ( "context" "crypto/aes" "crypto/cipher" "crypto/md5" "hash/fnv" "io" "sync" "time" "golang.org/x/crypto/chacha20poly1305" "v2ray.com/core/common/buf" "v2ray.com/core/common/crypto" "v2ray.com/core/common/errors" "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 token *signal.Semaphore ctx context.Context } func NewSessionHistory(ctx context.Context) *SessionHistory { h := &SessionHistory{ cache: make(map[sessionId]time.Time, 128), token: signal.NewSemaphore(1), ctx: ctx, } return h } func (h *SessionHistory) add(session sessionId) { h.Lock() h.cache[session] = time.Now().Add(time.Minute * 3) select { case <-h.token.Wait(): go h.run() default: } h.Unlock() } func (h *SessionHistory) has(session sessionId) bool { h.RLock() defer h.RUnlock() if expire, found := h.cache[session]; found { return expire.After(time.Now()) } return false } func (h *SessionHistory) run() { defer h.token.Signal() for { select { case <-h.ctx.Done(): return case <-time.After(time.Second * 30): } session2Remove := make([]sessionId, 0, 16) now := time.Now() h.Lock() if len(h.cache) == 0 { h.Unlock() return } for session, expire := range h.cache { if expire.Before(now) { session2Remove = append(session2Remove, session) } } for _, session := range session2Remove { delete(h.cache, session) } h.Unlock() } } func getSizeMask(b []byte) crypto.Uint16Generator { return crypto.NewShakeUint16Generator(b) } 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 (v *ServerSession) DecodeRequestHeader(reader io.Reader) (*protocol.RequestHeader, error) { buffer := make([]byte, 512) _, err := io.ReadFull(reader, buffer[:protocol.IDBytesLen]) if err != nil { return nil, errors.Base(err).Message("VMess|Server: Failed to read request header.") } user, timestamp, valid := v.userValidator.Get(buffer[:protocol.IDBytesLen]) if !valid { return nil, errors.New("VMess|Server: Invalid user.") } timestampHash := md5.New() timestampHash.Write(hashTimestamp(timestamp)) iv := timestampHash.Sum(nil) account, err := user.GetTypedAccount() if err != nil { return nil, errors.Base(err).Message("VMess|Server: Failed to get user account.") } vmessAccount := account.(*vmess.InternalAccount) aesStream := crypto.NewAesDecryptionStream(vmessAccount.ID.CmdKey(), iv) decryptor := crypto.NewCryptionReader(aesStream, reader) nBytes, err := io.ReadFull(decryptor, buffer[:41]) if err != nil { return nil, errors.Base(err).Message("VMess|Server: Failed to read request header.") } bufferLen := nBytes request := &protocol.RequestHeader{ User: user, Version: buffer[0], } if request.Version != Version { return nil, errors.New("VMess|Server: Invalid protocol version ", request.Version) } v.requestBodyIV = append([]byte(nil), buffer[1:17]...) // 16 bytes v.requestBodyKey = append([]byte(nil), buffer[17:33]...) // 16 bytes var sid sessionId copy(sid.user[:], vmessAccount.ID.Bytes()) copy(sid.key[:], v.requestBodyKey) copy(sid.nonce[:], v.requestBodyIV) if v.sessionHistory.has(sid) { return nil, errors.New("VMess|Server: Duplicated session id. Possibly under reply attack.") } v.sessionHistory.add(sid) v.responseHeader = buffer[33] // 1 byte request.Option = protocol.RequestOption(buffer[34]) // 1 byte padingLen := int(buffer[35] >> 4) request.Security = protocol.NormSecurity(protocol.Security(buffer[35] & 0x0F)) // 1 bytes reserved request.Command = protocol.RequestCommand(buffer[37]) request.Port = net.PortFromBytes(buffer[38:40]) switch buffer[40] { case AddrTypeIPv4: _, err = io.ReadFull(decryptor, buffer[41:45]) // 4 bytes bufferLen += 4 if err != nil { return nil, errors.Base(err).Message("VMess|Server: Failed to read IPv4.") } request.Address = net.IPAddress(buffer[41:45]) case AddrTypeIPv6: _, err = io.ReadFull(decryptor, buffer[41:57]) // 16 bytes bufferLen += 16 if err != nil { return nil, errors.Base(err).Message("VMess|Server: Failed to read IPv6 address.") } request.Address = net.IPAddress(buffer[41:57]) case AddrTypeDomain: _, err = io.ReadFull(decryptor, buffer[41:42]) if err != nil { return nil, errors.Base(err).Message("VMess:Server: Failed to read domain.") } domainLength := int(buffer[41]) if domainLength == 0 { return nil, errors.New("VMess|Server: Zero length domain.") } _, err = io.ReadFull(decryptor, buffer[42:42+domainLength]) if err != nil { return nil, errors.Base(err).Message("VMess|Server: Failed to read domain.") } bufferLen += 1 + domainLength request.Address = net.DomainAddress(string(buffer[42 : 42+domainLength])) } if padingLen > 0 { _, err = io.ReadFull(decryptor, buffer[bufferLen:bufferLen+padingLen]) if err != nil { return nil, errors.Base(err).Message("VMess|Server: Failed to read padding.") } bufferLen += padingLen } _, err = io.ReadFull(decryptor, buffer[bufferLen:bufferLen+4]) if err != nil { return nil, errors.Base(err).Message("VMess|Server: Failed to read checksum.") } fnv1a := fnv.New32a() fnv1a.Write(buffer[:bufferLen]) actualHash := fnv1a.Sum32() expectedHash := serial.BytesToUint32(buffer[bufferLen : bufferLen+4]) if actualHash != expectedHash { return nil, errors.New("VMess|Server: Invalid auth.") } if request.Address == nil { return nil, errors.New("VMess|Server: Invalid remote address.") } return request, nil } func (v *ServerSession) DecodeRequestBody(request *protocol.RequestHeader, reader io.Reader) buf.Reader { var authReader io.Reader var sizeMask crypto.Uint16Generator = crypto.StaticUint16Generator(0) if request.Option.Has(protocol.RequestOptionChunkMasking) { sizeMask = getSizeMask(v.requestBodyIV) } if request.Security.Is(protocol.SecurityType_NONE) { if request.Option.Has(protocol.RequestOptionChunkStream) { auth := &crypto.AEADAuthenticator{ AEAD: NoOpAuthenticator{}, NonceGenerator: crypto.NoOpBytesGenerator{}, AdditionalDataGenerator: crypto.NoOpBytesGenerator{}, } authReader = crypto.NewAuthenticationReader(auth, reader, sizeMask) } else { authReader = reader } } else if request.Security.Is(protocol.SecurityType_LEGACY) { aesStream := crypto.NewAesDecryptionStream(v.requestBodyKey, v.requestBodyIV) cryptionReader := crypto.NewCryptionReader(aesStream, reader) if request.Option.Has(protocol.RequestOptionChunkStream) { auth := &crypto.AEADAuthenticator{ AEAD: new(FnvAuthenticator), NonceGenerator: crypto.NoOpBytesGenerator{}, AdditionalDataGenerator: crypto.NoOpBytesGenerator{}, } authReader = crypto.NewAuthenticationReader(auth, cryptionReader, sizeMask) } else { authReader = cryptionReader } } else if request.Security.Is(protocol.SecurityType_AES128_GCM) { block, _ := aes.NewCipher(v.requestBodyKey) aead, _ := cipher.NewGCM(block) auth := &crypto.AEADAuthenticator{ AEAD: aead, NonceGenerator: &ChunkNonceGenerator{ Nonce: append([]byte(nil), v.requestBodyIV...), Size: aead.NonceSize(), }, AdditionalDataGenerator: crypto.NoOpBytesGenerator{}, } authReader = crypto.NewAuthenticationReader(auth, reader, sizeMask) } else if request.Security.Is(protocol.SecurityType_CHACHA20_POLY1305) { aead, _ := chacha20poly1305.New(GenerateChacha20Poly1305Key(v.requestBodyKey)) auth := &crypto.AEADAuthenticator{ AEAD: aead, NonceGenerator: &ChunkNonceGenerator{ Nonce: append([]byte(nil), v.requestBodyIV...), Size: aead.NonceSize(), }, AdditionalDataGenerator: crypto.NoOpBytesGenerator{}, } authReader = crypto.NewAuthenticationReader(auth, reader, sizeMask) } return buf.NewReader(authReader) } func (v *ServerSession) EncodeResponseHeader(header *protocol.ResponseHeader, writer io.Writer) { responseBodyKey := md5.Sum(v.requestBodyKey) responseBodyIV := md5.Sum(v.requestBodyIV) v.responseBodyKey = responseBodyKey[:] v.responseBodyIV = responseBodyIV[:] aesStream := crypto.NewAesEncryptionStream(v.responseBodyKey, v.responseBodyIV) encryptionWriter := crypto.NewCryptionWriter(aesStream, writer) v.responseWriter = encryptionWriter encryptionWriter.Write([]byte{v.responseHeader, byte(header.Option)}) err := MarshalCommand(header.Command, encryptionWriter) if err != nil { encryptionWriter.Write([]byte{0x00, 0x00}) } } func (v *ServerSession) EncodeResponseBody(request *protocol.RequestHeader, writer io.Writer) buf.Writer { var authWriter io.Writer var sizeMask crypto.Uint16Generator = crypto.StaticUint16Generator(0) if request.Option.Has(protocol.RequestOptionChunkMasking) { sizeMask = getSizeMask(v.responseBodyIV) } if request.Security.Is(protocol.SecurityType_NONE) { if request.Option.Has(protocol.RequestOptionChunkStream) { auth := &crypto.AEADAuthenticator{ AEAD: NoOpAuthenticator{}, NonceGenerator: crypto.NoOpBytesGenerator{}, AdditionalDataGenerator: crypto.NoOpBytesGenerator{}, } authWriter = crypto.NewAuthenticationWriter(auth, writer, sizeMask) } else { authWriter = writer } } else if request.Security.Is(protocol.SecurityType_LEGACY) { if request.Option.Has(protocol.RequestOptionChunkStream) { auth := &crypto.AEADAuthenticator{ AEAD: new(FnvAuthenticator), NonceGenerator: crypto.NoOpBytesGenerator{}, AdditionalDataGenerator: crypto.NoOpBytesGenerator{}, } authWriter = crypto.NewAuthenticationWriter(auth, v.responseWriter, sizeMask) } else { authWriter = v.responseWriter } } else if request.Security.Is(protocol.SecurityType_AES128_GCM) { block, _ := aes.NewCipher(v.responseBodyKey) aead, _ := cipher.NewGCM(block) auth := &crypto.AEADAuthenticator{ AEAD: aead, NonceGenerator: &ChunkNonceGenerator{ Nonce: append([]byte(nil), v.responseBodyIV...), Size: aead.NonceSize(), }, AdditionalDataGenerator: crypto.NoOpBytesGenerator{}, } authWriter = crypto.NewAuthenticationWriter(auth, writer, sizeMask) } else if request.Security.Is(protocol.SecurityType_CHACHA20_POLY1305) { aead, _ := chacha20poly1305.New(GenerateChacha20Poly1305Key(v.responseBodyKey)) auth := &crypto.AEADAuthenticator{ AEAD: aead, NonceGenerator: &ChunkNonceGenerator{ Nonce: append([]byte(nil), v.responseBodyIV...), Size: aead.NonceSize(), }, AdditionalDataGenerator: crypto.NoOpBytesGenerator{}, } authWriter = crypto.NewAuthenticationWriter(auth, writer, sizeMask) } return buf.NewWriter(authWriter) }