plugin/http_proxy: fix fragmented CONNECT method detection and add read deadline (#5296)

pkg/plugin/client/http_proxy_test.go

@@ -0,0 +1,107 @@
+// Copyright 2026 The frp Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build !frps
+
+package client
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"io"
+	"net"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+
+	v1 "github.com/fatedier/frp/pkg/config/v1"
+)
+
+func TestHTTPProxyHandleFragmentedConnectMethod(t *testing.T) {
+	require := require.New(t)
+
+	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	require.NoError(err)
+	defer ln.Close()
+
+	const payload = "ping"
+	echoErr := make(chan error, 1)
+	go func() {
+		conn, err := ln.Accept()
+		if err != nil {
+			echoErr <- err
+			return
+		}
+		defer conn.Close()
+
+		buf := make([]byte, len(payload))
+		if _, err = io.ReadFull(conn, buf); err != nil {
+			echoErr <- err
+			return
+		}
+		if string(buf) != payload {
+			echoErr <- fmt.Errorf("unexpected payload %q", string(buf))
+			return
+		}
+		_, err = conn.Write([]byte("echo:" + payload))
+		echoErr <- err
+	}()
+
+	hp := &HTTPProxy{
+		opts: &v1.HTTPProxyPluginOptions{},
+		l:    NewProxyListener(),
+	}
+
+	clientConn, serverConn := net.Pipe()
+	defer clientConn.Close()
+
+	go hp.Handle(context.Background(), &ConnectionInfo{
+		Conn:           serverConn,
+		UnderlyingConn: serverConn,
+	})
+
+	require.NoError(clientConn.SetDeadline(time.Now().Add(5 * time.Second)))
+
+	targetAddr := ln.Addr().String()
+	req := "CONNECT " + targetAddr + " HTTP/1.1\r\nHost: " + targetAddr + "\r\n\r\n"
+	_, err = clientConn.Write([]byte("CON"))
+	require.NoError(err)
+	_, err = clientConn.Write([]byte(req[len("CON"):]))
+	require.NoError(err)
+
+	rd := bufio.NewReader(clientConn)
+	status, err := rd.ReadString('\n')
+	require.NoError(err)
+	require.Equal("HTTP/1.1 200 OK\r\n", status)
+	line, err := rd.ReadString('\n')
+	require.NoError(err)
+	require.Equal("\r\n", line)
+
+	_, err = clientConn.Write([]byte(payload))
+	require.NoError(err)
+
+	got := make([]byte, len("echo:"+payload))
+	_, err = io.ReadFull(rd, got)
+	require.NoError(err)
+	require.Equal("echo:"+payload, string(got))
+
+	select {
+	case err := <-echoErr:
+		require.NoError(err)
+	case <-time.After(time.Second):
+		t.Fatal("timed out waiting for echo server")
+	}
+}