Improve packet-layer buffering and parsing logic
SendRicochetPacket now has error handling, correctly encodes channel ids, accepts any io.Writer, and ensures that all data is written. All callers should be changed at some point to handle errors also. RecvRicochetPackets is refactored to return only one packet per call and avoid reading more data than it will consume, which simplifies the logic and fixes a number of problems with short reads or large packets. Also fixed an error in bounds checking that caused a remote panic for invalid packet sizes. It also now accepts any io.Reader. Tests are updated and expanded, and now pass. Changes to Ricochet.processConnection are whitespace-only, because of the removal of the inner packets loop.
This commit is contained in:
John Brooks
Sarah Jamie Lewis
parent
cc50e0dfe9
commit
47ba383334
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@ -109,14 +109,12 @@ func (r *Ricochet) processConnection(oc *OpenConnection, service RicochetService
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return
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}
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packets, err := r.rni.RecvRicochetPackets(oc.conn)
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packet, err := r.rni.RecvRicochetPacket(oc.conn)
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if err != nil {
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oc.Close()
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return
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}
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for _, packet := range packets {
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if len(packet.Data) == 0 {
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service.OnChannelClosed(oc, packet.Channel)
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continue
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@ -325,7 +323,6 @@ func (r *Ricochet) processConnection(oc *OpenConnection, service RicochetService
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oc.Close()
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}
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}
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}
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}
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// Perform version negotiation on the connection, and create an OpenConnection if successful
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@ -1,10 +1,10 @@
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package utils
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import (
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"bytes"
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"encoding/binary"
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"errors"
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"net"
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"strconv"
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"io"
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)
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// RicochetData is a structure containing the raw data and the channel it the
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@ -14,79 +14,67 @@ type RicochetData struct {
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Data []byte
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}
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func (rd RicochetData) Equals(other RicochetData) bool {
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return rd.Channel == other.Channel && bytes.Equal(rd.Data, other.Data)
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}
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// RicochetNetworkInterface abstract operations that interact with ricochet's
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// packet layer.
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type RicochetNetworkInterface interface {
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Recv(conn net.Conn) ([]byte, error)
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SendRicochetPacket(conn net.Conn, channel int32, data []byte)
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RecvRicochetPackets(conn net.Conn) ([]RicochetData, error)
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SendRicochetPacket(dst io.Writer, channel int32, data []byte) error
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RecvRicochetPacket(reader io.Reader) (RicochetData, error)
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}
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// RicochetNetwork is a concrete implementation of the RicochetNetworkInterface
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type RicochetNetwork struct {
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}
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// Recv reads data from the client, and returns the raw byte array, else error.
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func (rn *RicochetNetwork) Recv(conn net.Conn) ([]byte, error) {
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buf := make([]byte, 4096)
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n, err := conn.Read(buf)
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if err != nil {
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return nil, err
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}
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ret := make([]byte, n)
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copy(ret[:], buf[:])
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return ret, nil
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}
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// SendRicochetPacket places the data into a structure needed for the client to
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// decode the packet and writes the packet to the network.
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func (rn *RicochetNetwork) SendRicochetPacket(conn net.Conn, channel int32, data []byte) {
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header := make([]byte, 4+len(data))
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header[0] = byte(len(header) >> 8)
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header[1] = byte(len(header) & 0x00FF)
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header[2] = 0x00
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header[3] = byte(channel)
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copy(header[4:], data[:])
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conn.Write(header)
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func (rn *RicochetNetwork) SendRicochetPacket(dst io.Writer, channel int32, data []byte) error {
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packet := make([]byte, 4+len(data))
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if len(packet) > 65535 {
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return errors.New("packet too large")
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}
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binary.BigEndian.PutUint16(packet[0:2], uint16(len(packet)))
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if channel < 0 || channel > 65535 {
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return errors.New("invalid channel ID")
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}
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binary.BigEndian.PutUint16(packet[2:4], uint16(channel))
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copy(packet[4:], data[:])
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for pos := 0; pos < len(packet); {
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n, err := dst.Write(packet[pos:])
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if err != nil {
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return err
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}
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pos += n
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}
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return nil
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}
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// RecvRicochetPackets returns an array of new messages received from the ricochet client
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func (rn *RicochetNetwork) RecvRicochetPackets(conn net.Conn) ([]RicochetData, error) {
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buf, err := rn.Recv(conn)
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if err != nil && len(buf) < 4 {
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return nil, errors.New("failed to retrieve new messages from the client")
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// RecvRicochetPacket returns the next packet from reader as a RicochetData
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// structure, or an error.
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func (rn *RicochetNetwork) RecvRicochetPacket(reader io.Reader) (RicochetData, error) {
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packet := RicochetData{}
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// Read the four-byte header to get packet length
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header := make([]byte, 4)
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if _, err := io.ReadAtLeast(reader, header, len(header)); err != nil {
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return packet, err
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}
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pos := 0
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finished := false
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var datas []RicochetData
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for !finished {
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size := int(binary.BigEndian.Uint16(buf[pos+0 : pos+2]))
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channel := int(binary.BigEndian.Uint16(buf[pos+2 : pos+4]))
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size := int(binary.BigEndian.Uint16(header[0:2]))
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if size < 4 {
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return datas, errors.New("invalid ricochet packet received (size=" + strconv.Itoa(size) + ")")
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return packet, errors.New("invalid packet length")
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}
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if pos+size > len(buf) {
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return datas, errors.New("partial data packet received")
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packet.Channel = int32(binary.BigEndian.Uint16(header[2:4]))
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packet.Data = make([]byte, size-4)
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if _, err := io.ReadAtLeast(reader, packet.Data, len(packet.Data)); err != nil {
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return packet, err
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}
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data := RicochetData{}
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data.Channel = int32(channel)
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if pos+4 >= len(buf) {
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data.Data = make([]byte, 0)
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} else {
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data.Data = buf[pos+4 : pos+size]
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}
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datas = append(datas, data)
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pos += size
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if pos >= len(buf) {
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finished = true
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}
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}
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return datas, nil
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return packet, nil
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}
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@ -1,171 +1,105 @@
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package utils
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import "testing"
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import "net"
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import "time"
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import (
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"bytes"
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"io"
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"testing"
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"testing/iotest"
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)
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type MockConn struct {
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Written []byte
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MockOutput []byte
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// Valid packets and their encoded forms
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var packetTests = []struct {
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packet RicochetData
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encoded []byte
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}{
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{RicochetData{1, []byte{}}, []byte{0x00, 0x04, 0x00, 0x01}},
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{RicochetData{65535, []byte{0xDE, 0xAD, 0xBE, 0xEF}}, []byte{0x00, 0x08, 0xFF, 0xFF, 0xDE, 0xAD, 0xBE, 0xEF}},
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{RicochetData{2, make([]byte, 65531)}, append([]byte{0xFF, 0xFF, 0x00, 0x02}, make([]byte, 65531)...)},
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}
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func (mc *MockConn) Read(b []byte) (int, error) {
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copy(b[:], mc.MockOutput[:])
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return len(mc.MockOutput), nil
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}
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func (mc *MockConn) Write(written []byte) (int, error) {
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mc.Written = written
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return 0, nil
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}
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func (mc *MockConn) LocalAddr() net.Addr {
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return nil
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}
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func (mc *MockConn) RemoteAddr() net.Addr {
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return nil
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}
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func (mc *MockConn) Close() error {
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return nil
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}
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func (mc *MockConn) SetDeadline(t time.Time) error {
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return nil
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}
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func (mc *MockConn) SetReadDeadline(t time.Time) error {
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return nil
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}
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func (mc *MockConn) SetWriteDeadline(t time.Time) error {
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return nil
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}
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func TestSentRicochetPacket(t *testing.T) {
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conn := new(MockConn)
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// Test sending valid packets
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func TestSendRicochetPacket(t *testing.T) {
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rni := RicochetNetwork{}
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rni.SendRicochetPacket(conn, 1, []byte{})
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if len(conn.Written) != 4 && conn.Written[0] != 0x00 && conn.Written[1] != 0x00 && conn.Written[2] != 0x01 && conn.Written[3] != 0x00 {
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t.Errorf("Output of SentRicochetPacket was Unexpected: %x", conn.Written)
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for _, td := range packetTests {
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var buf bytes.Buffer
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err := rni.SendRicochetPacket(&buf, td.packet.Channel, td.packet.Data)
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if err != nil {
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t.Errorf("Error sending packet %v: %v", td.packet, err)
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} else if !bytes.Equal(buf.Bytes(), td.encoded) {
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t.Errorf("Expected serialized packet %x but got %x", td.encoded, buf.Bytes())
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}
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}
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}
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func TestRecv(t *testing.T) {
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conn := new(MockConn)
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conn.MockOutput = []byte{0xDE, 0xAD, 0xBE, 0xEF}
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// Test sending invalid packets
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func TestSendRicochetPacket_Invalid(t *testing.T) {
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rni := RicochetNetwork{}
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buf, err := rni.Recv(conn)
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if err != nil || len(buf) != 4 || buf[0] != 0xDE || buf[1] != 0xAD || buf[2] != 0xBE || buf[3] != 0xEF {
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t.Errorf("Output of Recv was Unexpected: %x", buf)
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invalidPackets := []RicochetData{
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RicochetData{-1, []byte{}},
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RicochetData{65536, []byte{}},
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RicochetData{0, make([]byte, 65532)},
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}
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for _, td := range invalidPackets {
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var buf bytes.Buffer
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err := rni.SendRicochetPacket(&buf, td.Channel, td.Data)
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// Expect error
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if err == nil {
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t.Errorf("Expected error when sending invalid packet %v", td)
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}
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}
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}
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// Test receiving valid packets
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func TestRecvRicochetPacket(t *testing.T) {
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conn := new(MockConn)
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conn.MockOutput = []byte{00, 0x04, 0x00, 0x01}
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rni := RicochetNetwork{}
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rp, err := rni.RecvRicochetPackets(conn)
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if err != nil {
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t.Errorf("error extracting ricochet packets: %v", err)
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var buf bytes.Buffer
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for _, td := range packetTests {
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if _, err := buf.Write(td.encoded); err != nil {
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t.Error(err)
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return
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}
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}
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if len(rp) != 1 {
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t.Errorf("unexpected number of ricochet packets: %d", len(rp))
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// Use a HalfReader to test behavior on short socket reads also
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reader := iotest.HalfReader(&buf)
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rni := RicochetNetwork{}
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for _, td := range packetTests {
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packet, err := rni.RecvRicochetPacket(reader)
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if err != nil {
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t.Errorf("Error receiving packet %v: %v", td.packet, err)
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return
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} else if !packet.Equals(td.packet) {
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t.Errorf("Expected unserialized packet %v but got %v", td.packet, packet)
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}
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}
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if packet, err := rni.RecvRicochetPacket(reader); err != io.EOF {
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if err != nil {
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t.Errorf("Expected EOF on packet stream but received error: %v", err)
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} else {
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if rp[0].Channel != 1 {
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t.Errorf("channel number is Unexpected expected 1: %d", rp[0].Channel)
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}
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if len(rp[0].Data) != 0 {
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t.Errorf("expected emptry packet, instead got %x", rp[0].Data)
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t.Errorf("Expected EOF but received packet: %v", packet)
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}
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}
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}
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func TestRecvRicochetPacketInvalid(t *testing.T) {
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conn := new(MockConn)
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conn.MockOutput = []byte{00, 0x01, 0x00, 0x01}
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// Test receiving invalid packets
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func TestRecvRicochetPacket_Invalid(t *testing.T) {
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rni := RicochetNetwork{}
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_, err := rni.RecvRicochetPackets(conn)
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invalidPackets := [][]byte{
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[]byte{0x00, 0x00, 0x00, 0x00},
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[]byte{0x00, 0x03, 0x00, 0x00},
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[]byte{0xff},
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[]byte{0x00, 0x06, 0x00, 0x00, 0x00},
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[]byte{},
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}
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for _, td := range invalidPackets {
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buf := bytes.NewBuffer(td)
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packet, err := rni.RecvRicochetPacket(buf)
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// Expect error
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if err == nil {
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t.Errorf("recv should have errored due to invalid packets %v", err)
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t.Errorf("Expected error when sending invalid packet %x, got packet %v", td, packet)
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}
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conn.MockOutput = []byte{00, 0x0A, 0x00, 0x01}
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_, err = rni.RecvRicochetPackets(conn)
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if err == nil {
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t.Errorf("recv should have errored due to invalid packets %v", err)
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}
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}
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func TestRecvRicochetPacketLong(t *testing.T) {
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conn := new(MockConn)
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conn.MockOutput = []byte{0x00, 0x08, 0x00, 0xFF, 0xDE, 0xAD, 0xBE, 0xEF}
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rni := RicochetNetwork{}
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rp, err := rni.RecvRicochetPackets(conn)
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if err != nil {
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t.Errorf("error extracting ricochet packets: %v", err)
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return
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}
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if len(rp) != 1 {
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t.Errorf("unexpected number of ricochet packets: %d", len(rp))
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} else {
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if rp[0].Channel != 255 {
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t.Errorf("channel number is Unexpected expected 255 got: %d", rp[0].Channel)
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}
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if len(rp[0].Data) != 4 || rp[0].Data[0] != 0xDE || rp[0].Data[1] != 0xAD || rp[0].Data[2] != 0xBE || rp[0].Data[3] != 0xEF {
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t.Errorf("expected 0xDEADBEEF packet, instead got %x", rp[0].Data)
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}
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}
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}
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func TestRecvRicochetPacketMultiplex(t *testing.T) {
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conn := new(MockConn)
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conn.MockOutput = []byte{0x00, 0x04, 0x00, 0x01, 0x00, 0x08, 0x00, 0xFF, 0xDE, 0xAD, 0xBE, 0xEF}
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rni := RicochetNetwork{}
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rp, err := rni.RecvRicochetPackets(conn)
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if err != nil {
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t.Errorf("error extracting ricochet packets: %v", err)
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return
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}
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if len(rp) != 2 {
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t.Errorf("unexpected number of ricochet packets, expected 2 gt: %d", len(rp))
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} else {
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if rp[0].Channel != 1 {
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t.Errorf("channel number is Unexpected expected 1: %d", rp[0].Channel)
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}
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if len(rp[0].Data) != 0 {
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t.Errorf("expected empty packet, instead got %x", rp[0].Data)
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}
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if rp[1].Channel != 255 {
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t.Errorf("channel number is Unexpected expected 255 got: %d", rp[0].Channel)
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}
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if len(rp[1].Data) != 4 || rp[1].Data[0] != 0xDE || rp[1].Data[1] != 0xAD || rp[1].Data[2] != 0xBE || rp[1].Data[3] != 0xEF {
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t.Errorf("expected 0xDEADBEEF packet, instead got %x", rp[0].Data)
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}
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}
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}
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Loading…
Reference in New Issue