AUTH-1070: added SSH/protocol forwarding

carrier/carrier.go

@@ -0,0 +1,131 @@
+//Package carrier provides a WebSocket proxy to carry or proxy a connection
+//from the local client to the edge. See it as a wrapper around any protocol
+//that it packages up in a WebSocket connection to the edge.
+package carrier
+
+import (
+	"errors"
+	"io"
+	"net"
+	"net/http"
+	"os"
+	"strings"
+
+	"github.com/cloudflare/cloudflared/cmd/cloudflared/access"
+	"github.com/cloudflare/cloudflared/websocket"
+	"github.com/sirupsen/logrus"
+)
+
+// StdinoutStream is empty struct for wrapping stdin/stdout
+// into a single ReadWriter
+type StdinoutStream struct {
+}
+
+// Read will read from Stdin
+func (c *StdinoutStream) Read(p []byte) (int, error) {
+	return os.Stdin.Read(p)
+
+}
+
+// Write will write to Stdout
+func (c *StdinoutStream) Write(p []byte) (int, error) {
+	return os.Stdout.Write(p)
+}
+
+// StartClient will copy the data from stdin/stdout over a WebSocket connection
+// to the edge (originURL)
+func StartClient(logger *logrus.Logger, originURL string, stream io.ReadWriter) error {
+	return serveStream(logger, originURL, stream)
+}
+
+// StartServer will setup a server on a specified port and copy data over a WebSocket connection
+// to the edge (originURL)
+func StartServer(logger *logrus.Logger, address, originURL string, shutdownC <-chan struct{}) error {
+	listener, err := net.Listen("tcp", address)
+	if err != nil {
+		logger.WithError(err).Error("failed to start forwarding server")
+		return err
+	}
+	defer listener.Close()
+	for {
+		select {
+		case <-shutdownC:
+			return nil
+		default:
+			conn, err := listener.Accept()
+			if err != nil {
+				return err
+			}
+			go serveConnection(logger, conn, originURL)
+		}
+	}
+}
+
+// serveConnection handles connections for the StartServer call
+func serveConnection(logger *logrus.Logger, c net.Conn, originURL string) {
+	defer c.Close()
+	serveStream(logger, originURL, c)
+}
+
+// serveStream will serve the data over the WebSocket stream
+func serveStream(logger *logrus.Logger, originURL string, conn io.ReadWriter) error {
+	wsConn, err := createWebsocketStream(originURL)
+	if err != nil {
+		logger.WithError(err).Error("failed to create websocket stream")
+		return err
+	}
+	defer wsConn.Close()
+
+	websocket.Stream(wsConn, conn)
+
+	return nil
+}
+
+// createWebsocketStream will create a WebSocket connection to stream data over
+// It also handles redirects from Access and will present that flow if
+// the token is not present on the request
+func createWebsocketStream(originURL string) (*websocket.Conn, error) {
+	req, err := http.NewRequest(http.MethodGet, originURL, nil)
+	if err != nil {
+		return nil, err
+	}
+	wsConn, resp, err := websocket.ClientConnect(req, nil)
+	if err != nil && resp != nil && resp.StatusCode > 300 {
+		location, err := resp.Location()
+		if err != nil {
+			return nil, err
+		}
+		if !strings.Contains(location.String(), "cdn-cgi/access/login") {
+			return nil, errors.New("not an Access redirect")
+		}
+		req, err := buildAccessRequest(originURL)
+		if err != nil {
+			return nil, err
+		}
+
+		wsConn, _, err = websocket.ClientConnect(req, nil)
+		if err != nil {
+			return nil, err
+		}
+	} else if err != nil {
+		return nil, err
+	}
+
+	return &websocket.Conn{Conn: wsConn}, nil
+}
+
+// buildAccessRequest builds an HTTP request with the Access token set
+func buildAccessRequest(originURL string) (*http.Request, error) {
+	req, err := http.NewRequest(http.MethodGet, originURL, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	token, err := access.FetchToken(req.URL)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("cf-access-token", token)
+
+	return req, nil
+}

carrier/carrier_test.go

@@ -0,0 +1,117 @@
+package carrier
+
+import (
+	"bytes"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"sync"
+	"testing"
+
+	ws "github.com/gorilla/websocket"
+	"github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/assert"
+)
+
+const (
+	// example in Sec-Websocket-Key in rfc6455
+	testSecWebsocketKey = "dGhlIHNhbXBsZSBub25jZQ=="
+)
+
+type testStreamer struct {
+	buf *bytes.Buffer
+	l   sync.RWMutex
+}
+
+func newTestStream() *testStreamer {
+	return &testStreamer{buf: new(bytes.Buffer)}
+}
+
+func (s *testStreamer) Read(p []byte) (int, error) {
+	s.l.RLock()
+	defer s.l.RUnlock()
+	return s.buf.Read(p)
+
+}
+
+func (s *testStreamer) Write(p []byte) (int, error) {
+	s.l.Lock()
+	defer s.l.Unlock()
+	return s.buf.Write(p)
+}
+
+func TestStartClient(t *testing.T) {
+	message := "Good morning Austin! Time for another sunny day in the great state of Texas."
+	logger := logrus.New()
+	ts := newTestWebSocketServer()
+	defer ts.Close()
+
+	buf := newTestStream()
+	err := StartClient(logger, "http://"+ts.Listener.Addr().String(), buf)
+	assert.NoError(t, err)
+	buf.Write([]byte(message))
+
+	readBuffer := make([]byte, len(message))
+	buf.Read(readBuffer)
+	assert.Equal(t, message, string(readBuffer))
+}
+
+func TestStartServer(t *testing.T) {
+	listenerAddress := "localhost:1117"
+	message := "Good morning Austin! Time for another sunny day in the great state of Texas."
+	logger := logrus.New()
+	shutdownC := make(chan struct{})
+	ts := newTestWebSocketServer()
+	defer ts.Close()
+
+	go func() {
+		StartServer(logger, listenerAddress, "http://"+ts.Listener.Addr().String(), shutdownC)
+	}()
+
+	conn, err := net.Dial("tcp", listenerAddress)
+	assert.NoError(t, err)
+	conn.Write([]byte(message))
+
+	readBuffer := make([]byte, len(message))
+	conn.Read(readBuffer)
+	assert.Equal(t, string(readBuffer), message)
+}
+
+func newTestWebSocketServer() *httptest.Server {
+	upgrader := ws.Upgrader{
+		ReadBufferSize:  1024,
+		WriteBufferSize: 1024,
+	}
+
+	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		conn, _ := upgrader.Upgrade(w, r, nil)
+		defer conn.Close()
+		for {
+			mt, message, err := conn.ReadMessage()
+			if err != nil {
+				break
+			}
+
+			if err := conn.WriteMessage(mt, []byte(message)); err != nil {
+				break
+			}
+		}
+	}))
+}
+
+func testRequest(t *testing.T, url string, stream io.ReadWriter) *http.Request {
+	req, err := http.NewRequest("GET", url, stream)
+	if err != nil {
+		t.Fatalf("testRequestHeader error")
+	}
+
+	req.Header.Add("Connection", "Upgrade")
+	req.Header.Add("Upgrade", "WebSocket")
+	req.Header.Add("Sec-Websocket-Key", testSecWebsocketKey)
+	req.Header.Add("Sec-Websocket-Protocol", "tunnel-protocol")
+	req.Header.Add("Sec-Websocket-Version", "13")
+	req.Header.Add("User-Agent", "curl/7.59.0")
+
+	return req
+}