diff options
| -rw-r--r-- | pkg/tcpip/transport/tcp/endpoint.go | 6 | ||||
| -rw-r--r-- | pkg/tcpip/transport/tcp/tcp_test.go | 32 |
2 files changed, 38 insertions, 0 deletions
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go index 1ed4ba419..9945fdd6b 100644 --- a/pkg/tcpip/transport/tcp/endpoint.go +++ b/pkg/tcpip/transport/tcp/endpoint.go @@ -1530,6 +1530,12 @@ func (e *endpoint) queueSegment(p tcpip.Payloader, opts tcpip.WriteOptions) (*se if err != nil { return nil, 0, err } + + // Do not queue zero length segments. + if len(v) == 0 { + return nil, 0, nil + } + if !opts.Atomic { // Since we released locks in between it's possible that the // endpoint transitioned to a CLOSED/ERROR states so make diff --git a/pkg/tcpip/transport/tcp/tcp_test.go b/pkg/tcpip/transport/tcp/tcp_test.go index 71c4aa85d..3f67a1f1c 100644 --- a/pkg/tcpip/transport/tcp/tcp_test.go +++ b/pkg/tcpip/transport/tcp/tcp_test.go @@ -3624,6 +3624,38 @@ func TestMaxRTO(t *testing.T) { } } +// TestZeroSizedWriteRetransmit tests that a zero sized write should not +// result in a panic on an RTO as no segment should have been queued for +// a zero sized write. +func TestZeroSizedWriteRetransmit(t *testing.T) { + c := context.New(t, defaultMTU) + defer c.Cleanup() + + c.CreateConnected(context.TestInitialSequenceNumber, 30000 /* rcvWnd */, -1 /* epRcvBuf */) + + var r bytes.Reader + _, err := c.EP.Write(&r, tcpip.WriteOptions{}) + if err != nil { + t.Fatalf("Write failed: %s", err) + } + // Now do a non-zero sized write to trigger actual sending of data. + r.Reset(make([]byte, 1)) + _, err = c.EP.Write(&r, tcpip.WriteOptions{}) + if err != nil { + t.Fatalf("Write failed: %s", err) + } + // Do not ACK the packet and expect an original transmit and a + // retransmit. This should not cause a panic. + for i := 0; i < 2; i++ { + checker.IPv4(t, c.GetPacket(), + checker.TCP( + checker.DstPort(context.TestPort), + checker.TCPFlagsMatch(header.TCPFlagAck, ^header.TCPFlagPsh), + ), + ) + } +} + // TestRetransmitIPv4IDUniqueness tests that the IPv4 Identification field is // unique on retransmits. func TestRetransmitIPv4IDUniqueness(t *testing.T) { |