http3: reject duplicate control streams opened by the client

http3/server.go

@@ -12,6 +12,7 @@ import (
  "strconv"
  "strings"
  "sync"
+ "sync/atomic"
  "time"
 
  "github.com/quic-go/quic-go"
@@ -498,6 +499,8 @@ func (s *Server) handleConn(conn quic.Connection) error {
 }
 
 func (s *Server) handleUnidirectionalStreams(conn quic.Connection) {
+ var rcvdControlStream atomic.Bool
+
  for {
  str, err := conn.AcceptUniStream(context.Background())
  if err != nil {
@@ -531,6 +534,11 @@ func (s *Server) handleUnidirectionalStreams(conn quic.Connection) {
  str.CancelRead(quic.StreamErrorCode(ErrCodeStreamCreationError))
  return
  }
+ // Only a single control stream is allowed.
+ if isFirstControlStr := rcvdControlStream.CompareAndSwap(false, true); !isFirstControlStr {
+ conn.CloseWithError(quic.ApplicationErrorCode(ErrCodeStreamCreationError), "duplicate control stream")
+ return
+ }
  f, err := parseNextFrame(str, nil)
  if err != nil {
  conn.CloseWithError(quic.ApplicationErrorCode(ErrCodeFrameError), "")

http3/server_test.go

@@ -16,6 +16,7 @@ import (
  "github.com/quic-go/quic-go"
  mockquic "github.com/quic-go/quic-go/internal/mocks/quic"
  "github.com/quic-go/quic-go/internal/protocol"
+ "github.com/quic-go/quic-go/internal/qerr"
  "github.com/quic-go/quic-go/internal/testdata"
  "github.com/quic-go/quic-go/internal/utils"
  "github.com/quic-go/quic-go/quicvarint"
@@ -497,7 +498,7 @@ var _ = Describe("Server", func() {
 
  Context("control stream handling", func() {
  var conn *mockquic.MockEarlyConnection
- testDone := make(chan struct{})
+ testDone := make(chan struct{}, 1)
 
  BeforeEach(func() {
  conn = mockquic.NewMockEarlyConnection(mockCtrl)
@@ -528,6 +529,34 @@ var _ = Describe("Server", func() {
  time.Sleep(scaleDuration(20 * time.Millisecond)) // don't EXPECT any calls to conn.CloseWithError
  })
 
+ It("rejects duplicate control streams", func() {
+ b := quicvarint.Append(nil, streamTypeControlStream)
+ b = (&settingsFrame{}).Append(b)
+ r1 := bytes.NewReader(b)
+ controlStr1 := mockquic.NewMockStream(mockCtrl)
+ controlStr1.EXPECT().Read(gomock.Any()).DoAndReturn(r1.Read).AnyTimes()
+ r2 := bytes.NewReader(b)
+ controlStr2 := mockquic.NewMockStream(mockCtrl)
+ controlStr2.EXPECT().Read(gomock.Any()).DoAndReturn(r2.Read).AnyTimes()
+ done := make(chan struct{})
+ conn.EXPECT().CloseWithError(qerr.ApplicationErrorCode(ErrCodeStreamCreationError), "duplicate control stream").Do(func(qerr.ApplicationErrorCode, string) error {
+ close(done)
+ return nil
+ })
+ conn.EXPECT().AcceptUniStream(gomock.Any()).DoAndReturn(func(context.Context) (quic.ReceiveStream, error) {
+ return controlStr1, nil
+ })
+ conn.EXPECT().AcceptUniStream(gomock.Any()).DoAndReturn(func(context.Context) (quic.ReceiveStream, error) {
+ return controlStr2, nil
+ })
+ conn.EXPECT().AcceptUniStream(gomock.Any()).DoAndReturn(func(context.Context) (quic.ReceiveStream, error) {
+ <-done
+ return nil, errors.New("test done")
+ })
+ s.handleConn(conn)
+ Eventually(done).Should(BeClosed())
+ })
+
  for _, t := range []uint64{streamTypeQPACKEncoderStream, streamTypeQPACKDecoderStream} {
  streamType := t
  name := "encoder"