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Fix DoS attack vulnerability in VMess Option Processing
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@xiaokangwang @yuhan6665
xiaokangwang authored and yuhan6665 committed Jun 19, 2022
1 parent ba4ce4c commit d4f18b1
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Showing 4 changed files with 72 additions and 45 deletions.
48 changes: 28 additions & 20 deletions proxy/vmess/encoding/client.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -136,31 +136,35 @@ func (c *ClientSession) EncodeRequestHeader(header *protocol.RequestHeader, writ
return nil
}

func (c *ClientSession) EncodeRequestBody(request *protocol.RequestHeader, writer io.Writer) buf.Writer {
func (c *ClientSession) EncodeRequestBody(request *protocol.RequestHeader, writer io.Writer) (buf.Writer, error) {
var sizeParser crypto.ChunkSizeEncoder = crypto.PlainChunkSizeParser{}
if request.Option.Has(protocol.RequestOptionChunkMasking) {
sizeParser = NewShakeSizeParser(c.requestBodyIV[:])
}
var padding crypto.PaddingLengthGenerator
if request.Option.Has(protocol.RequestOptionGlobalPadding) {
padding = sizeParser.(crypto.PaddingLengthGenerator)
var ok bool
padding, ok = sizeParser.(crypto.PaddingLengthGenerator)
if !ok {
return nil, newError("invalid option: RequestOptionGlobalPadding")
}
}

switch request.Security {
case protocol.SecurityType_NONE:
if request.Option.Has(protocol.RequestOptionChunkStream) {
if request.Command.TransferType() == protocol.TransferTypeStream {
return crypto.NewChunkStreamWriter(sizeParser, writer)
return crypto.NewChunkStreamWriter(sizeParser, writer), nil
}
auth := &crypto.AEADAuthenticator{
AEAD: new(NoOpAuthenticator),
NonceGenerator: crypto.GenerateEmptyBytes(),
AdditionalDataGenerator: crypto.GenerateEmptyBytes(),
}
return crypto.NewAuthenticationWriter(auth, sizeParser, writer, protocol.TransferTypePacket, padding)
return crypto.NewAuthenticationWriter(auth, sizeParser, writer, protocol.TransferTypePacket, padding), nil
}

return buf.NewWriter(writer)
return buf.NewWriter(writer), nil
case protocol.SecurityType_LEGACY:
aesStream := crypto.NewAesEncryptionStream(c.requestBodyKey[:], c.requestBodyIV[:])
cryptionWriter := crypto.NewCryptionWriter(aesStream, writer)
Expand All @@ -170,10 +174,10 @@ func (c *ClientSession) EncodeRequestBody(request *protocol.RequestHeader, write
NonceGenerator: crypto.GenerateEmptyBytes(),
AdditionalDataGenerator: crypto.GenerateEmptyBytes(),
}
return crypto.NewAuthenticationWriter(auth, sizeParser, cryptionWriter, request.Command.TransferType(), padding)
return crypto.NewAuthenticationWriter(auth, sizeParser, cryptionWriter, request.Command.TransferType(), padding), nil
}

return &buf.SequentialWriter{Writer: cryptionWriter}
return &buf.SequentialWriter{Writer: cryptionWriter}, nil
case protocol.SecurityType_AES128_GCM:
aead := crypto.NewAesGcm(c.requestBodyKey[:])
auth := &crypto.AEADAuthenticator{
Expand All @@ -192,7 +196,7 @@ func (c *ClientSession) EncodeRequestBody(request *protocol.RequestHeader, write
}
sizeParser = NewAEADSizeParser(lengthAuth)
}
return crypto.NewAuthenticationWriter(auth, sizeParser, writer, request.Command.TransferType(), padding)
return crypto.NewAuthenticationWriter(auth, sizeParser, writer, request.Command.TransferType(), padding), nil
case protocol.SecurityType_CHACHA20_POLY1305:
aead, err := chacha20poly1305.New(GenerateChacha20Poly1305Key(c.requestBodyKey[:]))
common.Must(err)
Expand All @@ -214,9 +218,9 @@ func (c *ClientSession) EncodeRequestBody(request *protocol.RequestHeader, write
}
sizeParser = NewAEADSizeParser(lengthAuth)
}
return crypto.NewAuthenticationWriter(auth, sizeParser, writer, request.Command.TransferType(), padding)
return crypto.NewAuthenticationWriter(auth, sizeParser, writer, request.Command.TransferType(), padding), nil
default:
panic("Unknown security type.")
return nil, newError("invalid option: Security")
}
}

Expand Down Expand Up @@ -305,21 +309,25 @@ func (c *ClientSession) DecodeResponseHeader(reader io.Reader) (*protocol.Respon
return header, nil
}

func (c *ClientSession) DecodeResponseBody(request *protocol.RequestHeader, reader io.Reader) buf.Reader {
func (c *ClientSession) DecodeResponseBody(request *protocol.RequestHeader, reader io.Reader) (buf.Reader, error) {
var sizeParser crypto.ChunkSizeDecoder = crypto.PlainChunkSizeParser{}
if request.Option.Has(protocol.RequestOptionChunkMasking) {
sizeParser = NewShakeSizeParser(c.responseBodyIV[:])
}
var padding crypto.PaddingLengthGenerator
if request.Option.Has(protocol.RequestOptionGlobalPadding) {
padding = sizeParser.(crypto.PaddingLengthGenerator)
var ok bool
padding, ok = sizeParser.(crypto.PaddingLengthGenerator)
if !ok {
return nil, newError("invalid option: RequestOptionGlobalPadding")
}
}

switch request.Security {
case protocol.SecurityType_NONE:
if request.Option.Has(protocol.RequestOptionChunkStream) {
if request.Command.TransferType() == protocol.TransferTypeStream {
return crypto.NewChunkStreamReader(sizeParser, reader)
return crypto.NewChunkStreamReader(sizeParser, reader), nil
}

auth := &crypto.AEADAuthenticator{
Expand All @@ -328,21 +336,21 @@ func (c *ClientSession) DecodeResponseBody(request *protocol.RequestHeader, read
AdditionalDataGenerator: crypto.GenerateEmptyBytes(),
}

return crypto.NewAuthenticationReader(auth, sizeParser, reader, protocol.TransferTypePacket, padding)
return crypto.NewAuthenticationReader(auth, sizeParser, reader, protocol.TransferTypePacket, padding), nil
}

return buf.NewReader(reader)
return buf.NewReader(reader), nil
case protocol.SecurityType_LEGACY:
if request.Option.Has(protocol.RequestOptionChunkStream) {
auth := &crypto.AEADAuthenticator{
AEAD: new(FnvAuthenticator),
NonceGenerator: crypto.GenerateEmptyBytes(),
AdditionalDataGenerator: crypto.GenerateEmptyBytes(),
}
return crypto.NewAuthenticationReader(auth, sizeParser, c.responseReader, request.Command.TransferType(), padding)
return crypto.NewAuthenticationReader(auth, sizeParser, c.responseReader, request.Command.TransferType(), padding), nil
}

return buf.NewReader(c.responseReader)
return buf.NewReader(c.responseReader), nil
case protocol.SecurityType_AES128_GCM:
aead := crypto.NewAesGcm(c.responseBodyKey[:])

Expand All @@ -362,7 +370,7 @@ func (c *ClientSession) DecodeResponseBody(request *protocol.RequestHeader, read
}
sizeParser = NewAEADSizeParser(lengthAuth)
}
return crypto.NewAuthenticationReader(auth, sizeParser, reader, request.Command.TransferType(), padding)
return crypto.NewAuthenticationReader(auth, sizeParser, reader, request.Command.TransferType(), padding), nil
case protocol.SecurityType_CHACHA20_POLY1305:
aead, _ := chacha20poly1305.New(GenerateChacha20Poly1305Key(c.responseBodyKey[:]))

Expand All @@ -383,9 +391,9 @@ func (c *ClientSession) DecodeResponseBody(request *protocol.RequestHeader, read
}
sizeParser = NewAEADSizeParser(lengthAuth)
}
return crypto.NewAuthenticationReader(auth, sizeParser, reader, request.Command.TransferType(), padding)
return crypto.NewAuthenticationReader(auth, sizeParser, reader, request.Command.TransferType(), padding), nil
default:
panic("Unknown security type.")
return nil, newError("invalid option: Security")
}
}

Expand Down
48 changes: 28 additions & 20 deletions proxy/vmess/encoding/server.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -310,31 +310,35 @@ func (s *ServerSession) DecodeRequestHeader(reader io.Reader, isDrain bool) (*pr
}

// DecodeRequestBody returns Reader from which caller can fetch decrypted body.
func (s *ServerSession) DecodeRequestBody(request *protocol.RequestHeader, reader io.Reader) buf.Reader {
func (s *ServerSession) DecodeRequestBody(request *protocol.RequestHeader, reader io.Reader) (buf.Reader, error) {
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)
var ok bool
padding, ok = sizeParser.(crypto.PaddingLengthGenerator)
if !ok {
return nil, newError("invalid option: RequestOptionGlobalPadding")
}
}

switch request.Security {
case protocol.SecurityType_NONE:
if request.Option.Has(protocol.RequestOptionChunkStream) {
if request.Command.TransferType() == protocol.TransferTypeStream {
return crypto.NewChunkStreamReader(sizeParser, reader)
return crypto.NewChunkStreamReader(sizeParser, reader), nil
}

auth := &crypto.AEADAuthenticator{
AEAD: new(NoOpAuthenticator),
NonceGenerator: crypto.GenerateEmptyBytes(),
AdditionalDataGenerator: crypto.GenerateEmptyBytes(),
}
return crypto.NewAuthenticationReader(auth, sizeParser, reader, protocol.TransferTypePacket, padding)
return crypto.NewAuthenticationReader(auth, sizeParser, reader, protocol.TransferTypePacket, padding), nil
}
return buf.NewReader(reader)
return buf.NewReader(reader), nil

case protocol.SecurityType_LEGACY:
aesStream := crypto.NewAesDecryptionStream(s.requestBodyKey[:], s.requestBodyIV[:])
Expand All @@ -345,9 +349,9 @@ func (s *ServerSession) DecodeRequestBody(request *protocol.RequestHeader, reade
NonceGenerator: crypto.GenerateEmptyBytes(),
AdditionalDataGenerator: crypto.GenerateEmptyBytes(),
}
return crypto.NewAuthenticationReader(auth, sizeParser, cryptionReader, request.Command.TransferType(), padding)
return crypto.NewAuthenticationReader(auth, sizeParser, cryptionReader, request.Command.TransferType(), padding), nil
}
return buf.NewReader(cryptionReader)
return buf.NewReader(cryptionReader), nil

case protocol.SecurityType_AES128_GCM:
aead := crypto.NewAesGcm(s.requestBodyKey[:])
Expand All @@ -367,7 +371,7 @@ func (s *ServerSession) DecodeRequestBody(request *protocol.RequestHeader, reade
}
sizeParser = NewAEADSizeParser(lengthAuth)
}
return crypto.NewAuthenticationReader(auth, sizeParser, reader, request.Command.TransferType(), padding)
return crypto.NewAuthenticationReader(auth, sizeParser, reader, request.Command.TransferType(), padding), nil

case protocol.SecurityType_CHACHA20_POLY1305:
aead, _ := chacha20poly1305.New(GenerateChacha20Poly1305Key(s.requestBodyKey[:]))
Expand All @@ -389,10 +393,10 @@ func (s *ServerSession) DecodeRequestBody(request *protocol.RequestHeader, reade
}
sizeParser = NewAEADSizeParser(lengthAuth)
}
return crypto.NewAuthenticationReader(auth, sizeParser, reader, request.Command.TransferType(), padding)
return crypto.NewAuthenticationReader(auth, sizeParser, reader, request.Command.TransferType(), padding), nil

default:
panic("Unknown security type.")
return nil, newError("invalid option: Security")
}
}

Expand Down Expand Up @@ -453,31 +457,35 @@ func (s *ServerSession) EncodeResponseHeader(header *protocol.ResponseHeader, wr
}

// EncodeResponseBody returns a Writer that auto-encrypt content written by caller.
func (s *ServerSession) EncodeResponseBody(request *protocol.RequestHeader, writer io.Writer) buf.Writer {
func (s *ServerSession) EncodeResponseBody(request *protocol.RequestHeader, writer io.Writer) (buf.Writer, error) {
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)
var ok bool
padding, ok = sizeParser.(crypto.PaddingLengthGenerator)
if !ok {
return nil, newError("invalid option: RequestOptionGlobalPadding")
}
}

switch request.Security {
case protocol.SecurityType_NONE:
if request.Option.Has(protocol.RequestOptionChunkStream) {
if request.Command.TransferType() == protocol.TransferTypeStream {
return crypto.NewChunkStreamWriter(sizeParser, writer)
return crypto.NewChunkStreamWriter(sizeParser, writer), nil
}

auth := &crypto.AEADAuthenticator{
AEAD: new(NoOpAuthenticator),
NonceGenerator: crypto.GenerateEmptyBytes(),
AdditionalDataGenerator: crypto.GenerateEmptyBytes(),
}
return crypto.NewAuthenticationWriter(auth, sizeParser, writer, protocol.TransferTypePacket, padding)
return crypto.NewAuthenticationWriter(auth, sizeParser, writer, protocol.TransferTypePacket, padding), nil
}
return buf.NewWriter(writer)
return buf.NewWriter(writer), nil

case protocol.SecurityType_LEGACY:
if request.Option.Has(protocol.RequestOptionChunkStream) {
Expand All @@ -486,9 +494,9 @@ func (s *ServerSession) EncodeResponseBody(request *protocol.RequestHeader, writ
NonceGenerator: crypto.GenerateEmptyBytes(),
AdditionalDataGenerator: crypto.GenerateEmptyBytes(),
}
return crypto.NewAuthenticationWriter(auth, sizeParser, s.responseWriter, request.Command.TransferType(), padding)
return crypto.NewAuthenticationWriter(auth, sizeParser, s.responseWriter, request.Command.TransferType(), padding), nil
}
return &buf.SequentialWriter{Writer: s.responseWriter}
return &buf.SequentialWriter{Writer: s.responseWriter}, nil

case protocol.SecurityType_AES128_GCM:
aead := crypto.NewAesGcm(s.responseBodyKey[:])
Expand All @@ -508,7 +516,7 @@ func (s *ServerSession) EncodeResponseBody(request *protocol.RequestHeader, writ
}
sizeParser = NewAEADSizeParser(lengthAuth)
}
return crypto.NewAuthenticationWriter(auth, sizeParser, writer, request.Command.TransferType(), padding)
return crypto.NewAuthenticationWriter(auth, sizeParser, writer, request.Command.TransferType(), padding), nil

case protocol.SecurityType_CHACHA20_POLY1305:
aead, _ := chacha20poly1305.New(GenerateChacha20Poly1305Key(s.responseBodyKey[:]))
Expand All @@ -530,9 +538,9 @@ func (s *ServerSession) EncodeResponseBody(request *protocol.RequestHeader, writ
}
sizeParser = NewAEADSizeParser(lengthAuth)
}
return crypto.NewAuthenticationWriter(auth, sizeParser, writer, request.Command.TransferType(), padding)
return crypto.NewAuthenticationWriter(auth, sizeParser, writer, request.Command.TransferType(), padding), nil

default:
panic("Unknown security type.")
return nil, newError("invalid option: Security")
}
}
11 changes: 8 additions & 3 deletions proxy/vmess/inbound/inbound.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -184,8 +184,10 @@ func (h *Handler) RemoveUser(ctx context.Context, email string) error {
func transferResponse(timer signal.ActivityUpdater, session *encoding.ServerSession, request *protocol.RequestHeader, response *protocol.ResponseHeader, input buf.Reader, output *buf.BufferedWriter) error {
session.EncodeResponseHeader(response, output)

bodyWriter := session.EncodeResponseBody(request, output)

bodyWriter, err := session.EncodeResponseBody(request, output)
if err != nil {
return newError("failed to start decoding response").Base(err)
}
{
// Optimize for small response packet
data, err := input.ReadMultiBuffer()
Expand Down Expand Up @@ -301,7 +303,10 @@ func (h *Handler) Process(ctx context.Context, network net.Network, connection s
requestDone := func() error {
defer timer.SetTimeout(sessionPolicy.Timeouts.DownlinkOnly)

bodyReader := svrSession.DecodeRequestBody(request, reader)
bodyReader, err := svrSession.DecodeRequestBody(request, reader)
if err != nil {
return newError("failed to start decoding").Base(err)
}
if err := buf.Copy(bodyReader, link.Writer, buf.UpdateActivity(timer)); err != nil {
return newError("failed to transfer request").Base(err)
}
Expand Down
10 changes: 8 additions & 2 deletions proxy/vmess/outbound/outbound.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -158,7 +158,10 @@ func (h *Handler) Process(ctx context.Context, link *transport.Link, dialer inte
return newError("failed to encode request").Base(err).AtWarning()
}

bodyWriter := session.EncodeRequestBody(request, writer)
bodyWriter, err := session.EncodeRequestBody(request, writer)
if err != nil {
return newError("failed to start encoding").Base(err)
}
bodyWriter2 := bodyWriter
if request.Command == protocol.RequestCommandMux && request.Port == 666 {
bodyWriter = xudp.NewPacketWriter(bodyWriter, target)
Expand Down Expand Up @@ -194,7 +197,10 @@ func (h *Handler) Process(ctx context.Context, link *transport.Link, dialer inte
}
h.handleCommand(rec.Destination(), header.Command)

bodyReader := session.DecodeResponseBody(request, reader)
bodyReader, err := session.DecodeResponseBody(request, reader)
if err != nil {
return newError("failed to start encoding response").Base(err)
}
if request.Command == protocol.RequestCommandMux && request.Port == 666 {
bodyReader = xudp.NewPacketReader(&buf.BufferedReader{Reader: bodyReader})
}
Expand Down

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