return error empty StreamFrames that don't have the FinBit set

frames/stream_frame.go

@@ -6,6 +6,7 @@ import (
 	"io/ioutil"
 
 	"github.com/lucas-clemente/quic-go/protocol"
+	"github.com/lucas-clemente/quic-go/qerr"
 	"github.com/lucas-clemente/quic-go/utils"
 )
 
@@ -74,6 +75,10 @@ func ParseStreamFrame(r *bytes.Reader) (*StreamFrame, error) {
 		}
 	}
 
+	if !frame.FinBit && len(frame.Data) == 0 {
+		return nil, qerr.EmptyStreamFrameNoFin
+	}
+
 	return frame, nil
 }
 

frames/stream_frame_test.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 
 	"github.com/lucas-clemente/quic-go/protocol"
+	"github.com/lucas-clemente/quic-go/qerr"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 )
@@ -31,6 +32,21 @@ var _ = Describe("StreamFrame", func() {
 			Expect(frame.DataLenPresent).To(BeFalse())
 			Expect(frame.Data).To(Equal([]byte("foobar")))
 		})
+
+		It("accepts empty frame with finbit set", func() {
+			b := bytes.NewReader([]byte{0x80 ^ 0x40 ^ 0x20, 0x1, 0, 0})
+			frame, err := ParseStreamFrame(b)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(frame.FinBit).To(BeTrue())
+			Expect(frame.DataLenPresent).To(BeTrue())
+			Expect(frame.Data).To(HaveLen(0))
+		})
+
+		It("errors on empty stream frames that don't have the FinBit set", func() {
+			b := bytes.NewReader([]byte{0x80 ^ 0x20, 0x1, 0, 0})
+			_, err := ParseStreamFrame(b)
+			Expect(err).To(MatchError(qerr.EmptyStreamFrameNoFin))
+		})
 	})
 
 	Context("when writing", func() {