Revert "lua: prevent configuration files from being executed as scripts"

This reverts commit 796bbd763a.

common/platform/config_file.go

@@ -1,50 +0,0 @@
-package platform
-
-import (
-	"io"
-	"os"
-	"path/filepath"
-)
-
-type configFile struct {
-	path string
-	info os.FileInfo
-}
-
-var configFiles []configFile
-
-// ReadConfigFile reads a config source and records local regular files.
-func ReadConfigFile(file *os.File) ([]byte, error) {
-	info, err := file.Stat()
-	if err != nil {
-		return nil, err
-	}
-	path := ""
-	if info.Mode().IsRegular() && file != os.Stdin {
-		path, err = filepath.Abs(file.Name())
-		if err != nil {
-			return nil, err
-		}
-		path, err = filepath.EvalSymlinks(path)
-		if err != nil {
-			return nil, err
-		}
-	}
-	data, err := io.ReadAll(file)
-	if err != nil {
-		return nil, err
-	}
-	if info.Mode().IsRegular() {
-		configFiles = append(configFiles, configFile{path: path, info: info})
-	}
-	return data, nil
-}
-
-func isConfigFile(path string, info os.FileInfo) bool {
-	for _, file := range configFiles {
-		if file.path == path || os.SameFile(file.info, info) {
-			return true
-		}
-	}
-	return false
-}

common/platform/platform.go

@@ -113,18 +113,11 @@ func ResolveLuaFile(path string) (string, error) {
 			}
 		}
 	}
-	path, info, err := resolveFile(paths)
+	path, err := resolveFile(paths)
 	if err != nil {
 		return "", err
 	}
-	path, err = resolveLuaTarget(path)
-	if err != nil {
-		return "", err
-	}
-	if isConfigFile(path, info) {
-		return "", fmt.Errorf("Lua file was loaded as a configuration file: %s", path)
-	}
-	return path, nil
+	return resolveLuaTarget(path)
 }
 
 func resolveLuaTarget(path string) (string, error) {
@@ -138,12 +131,12 @@ func resolveLuaTarget(path string) (string, error) {
 	return path, nil
 }
 
-func resolveFile(paths []string) (string, os.FileInfo, error) {
+func resolveFile(paths []string) (string, error) {
 	var tried []string
 	for _, path := range paths {
 		path, err := filepath.Abs(path)
 		if err != nil {
-			return "", nil, fmt.Errorf("failed to resolve file path: %w", err)
+			return "", fmt.Errorf("failed to resolve file path: %w", err)
 		}
 		tried = append(tried, path)
 		info, err := os.Stat(path)
@@ -151,12 +144,12 @@ func resolveFile(paths []string) (string, os.FileInfo, error) {
 			continue
 		}
 		if err != nil {
-			return "", nil, fmt.Errorf("failed to inspect file %q: %w", path, err)
+			return "", fmt.Errorf("failed to inspect file %q: %w", path, err)
 		}
 		if !info.Mode().IsRegular() {
-			return "", nil, fmt.Errorf("file is not a regular file: %s", path)
+			return "", fmt.Errorf("file is not a regular file: %s", path)
 		}
-		return path, info, nil
+		return path, nil
 	}
-	return "", nil, fmt.Errorf("file not found; tried %q: %w", tried, os.ErrNotExist)
+	return "", fmt.Errorf("file not found; tried %q: %w", tried, os.ErrNotExist)
 }

infra/conf/serial/config_security_test.go

@@ -1,194 +0,0 @@
-package serial_test
-
-import (
-	"context"
-	"io"
-	"os"
-	"path/filepath"
-	"strings"
-	"testing"
-	"time"
-
-	xlua "github.com/xtls/xray-core/common/lua"
-	"github.com/xtls/xray-core/core"
-	"github.com/xtls/xray-core/infra/conf"
-	"github.com/xtls/xray-core/infra/conf/serial"
-	_ "github.com/xtls/xray-core/main/confloader/external"
-	glua "github.com/yuin/gopher-lua"
-)
-
-func TestConfigSourceSecurity(t *testing.T) {
-	// Keep registered files alive until every file identity check finishes.
-	dir := t.TempDir()
-	t.Run("polyglots", testConfigLuaPolyglots)
-	t.Run("merged", func(t *testing.T) { testMergedConfigCannotRunAsLua(t, dir) })
-	t.Run("hardlink", func(t *testing.T) { testConfigHardLinkCannotRunAsLua(t, dir) })
-	t.Run("stdin", func(t *testing.T) { testStdinConfigCannotRunAsLua(t, dir) })
-}
-
-func testConfigLuaPolyglots(t *testing.T) {
-	const luaBody = "polyglotExecuted = true\nfunction HandleRoute() return 'direct' end\n"
-	for _, tc := range []struct {
-		name   string
-		decode func(io.Reader) (*conf.Config, error)
-		source string
-		script string
-	}{
-		{"JSON", serial.DecodeJSONConfig, "null = 0\n" + luaBody, ""},
-		{"YAML", serial.DecodeYAMLConfig, `--[[: ignored
-routing:
-  script: payload.lua
---]] --: ignored
-_G: assert((function() polyglotExecuted = true; function HandleRoute() return 'direct' end end)())
-`, "payload.lua"},
-		{"TOML", serial.DecodeTOMLConfig, `routing = { script = "payload.lua" }
--- = """
-polyglotExecuted = true
-function HandleRoute() return 'direct' end
--- """
-`, "payload.lua"},
-	} {
-		t.Run(tc.name, func(t *testing.T) {
-			config, err := tc.decode(strings.NewReader(tc.source))
-			if err != nil {
-				t.Fatal(err)
-			}
-			script := ""
-			if config.RouterConfig != nil {
-				script = config.RouterConfig.Script
-			}
-			if script != tc.script {
-				t.Fatalf("routing.script = %q, want %q", script, tc.script)
-			}
-			if built, err := config.Build(); err != nil || built == nil {
-				t.Fatalf("config Build failed: %v", err)
-			}
-			if _, err := serial.DecodeJSONConfigStrict(strings.NewReader(tc.source)); err == nil {
-				t.Fatal("strict JSON accepted the polyglot")
-			}
-			dir := t.TempDir()
-			t.Setenv("xray.location.confdir", dir)
-			if err := os.WriteFile(filepath.Join(dir, "payload.lua"), []byte(tc.source), 0o600); err != nil {
-				t.Fatal(err)
-			}
-			configPath := filepath.Join(dir, "payload."+strings.ToLower(tc.name))
-			if err := os.WriteFile(configPath, []byte(tc.source), 0o600); err != nil {
-				t.Fatal(err)
-			}
-			if program, err := xlua.Compile(configPath); program != nil || err == nil || !strings.Contains(err.Error(), "Lua file extension must be .lua") {
-				t.Fatalf("Compile(%q) = %v, %v; want .lua extension rejection", configPath, program, err)
-			}
-			program, err := xlua.Compile("payload.lua")
-			if err != nil {
-				t.Fatal(err)
-			}
-			ctx, cancel := context.WithTimeout(context.Background(), time.Second)
-			defer cancel()
-			state, err := program.NewState(ctx, nil, nil)
-			if err != nil {
-				t.Fatal(err)
-			}
-			defer state.Close()
-			if state.GetGlobal("polyglotExecuted") != glua.LTrue {
-				t.Fatal("Lua top-level code did not execute")
-			}
-			if err := state.CallByParam(glua.P{Fn: state.GetGlobal("HandleRoute"), NRet: 1, Protect: true}); err != nil {
-				t.Fatal(err)
-			}
-			if got := state.Get(-1); got != glua.LString("direct") {
-				t.Fatalf("HandleRoute() = %v, want direct", got)
-			}
-			t.Logf("config built with routing.script=%q; the same bytes executed as Lua", script)
-		})
-	}
-}
-
-func testMergedConfigCannotRunAsLua(t *testing.T, dir string) {
-	t.Setenv("xray.location.confdir", dir)
-	base := filepath.Join(dir, "base.lua")
-	for format, body := range map[string]string{
-		"json": "null = 0\nfunction HandleRoute() return 'direct' end\n",
-		"yaml": "_G: assert((function() function HandleRoute() return 'direct' end end)())\n",
-		"toml": "-- = \"\"\"\nfunction HandleRoute() return 'direct' end\n-- \"\"\"\n",
-	} {
-		t.Run(format, func(t *testing.T) {
-			path := filepath.Join(dir, format+".lua")
-			if err := os.WriteFile(base, []byte(`{"routing":{"script":"`+format+`.lua"}}`), 0o600); err != nil {
-				t.Fatal(err)
-			}
-			if err := os.WriteFile(path, []byte(body), 0o600); err != nil {
-				t.Fatal(err)
-			}
-			if program, err := xlua.Compile(path); err != nil || program == nil {
-				t.Fatalf("fixture must compile before config loading: %v", err)
-			}
-			if _, err := serial.BuildConfig([]*core.ConfigSource{
-				{Name: base, Format: "json"},
-				{Name: path, Format: format},
-			}); err != nil {
-				t.Fatal(err)
-			}
-			for _, source := range []string{base, path} {
-				if program, err := xlua.Compile(source); program != nil || err == nil || !strings.Contains(err.Error(), "loaded as a configuration file") {
-					t.Fatalf("Compile(%q) = %v, %v; want config source rejection", source, program, err)
-				}
-			}
-			if err := os.Rename(path, path+".old"); err != nil {
-				t.Fatal(err)
-			}
-			if err := os.WriteFile(path, []byte("function HandleRoute() end"), 0o600); err != nil {
-				t.Fatal(err)
-			}
-			if program, err := xlua.Compile(path); program != nil || err == nil || !strings.Contains(err.Error(), "loaded as a configuration file") {
-				t.Fatalf("Compile = %v, %v; want replaced config path rejection", program, err)
-			}
-		})
-	}
-	path := filepath.Join(dir, "ordinary.lua")
-	if err := os.WriteFile(path, []byte("function HandleRoute() end"), 0o600); err != nil {
-		t.Fatal(err)
-	}
-	if program, err := xlua.Compile(path); err != nil || program == nil {
-		t.Fatalf("ordinary script in the config directory must remain usable: %v", err)
-	}
-}
-
-func testConfigHardLinkCannotRunAsLua(t *testing.T, dir string) {
-	path := filepath.Join(dir, "config.json")
-	if err := os.WriteFile(path, []byte("null = 0\nfunction HandleRoute() end"), 0o600); err != nil {
-		t.Fatal(err)
-	}
-	alias := filepath.Join(dir, "alias.lua")
-	if err := os.Link(path, alias); err != nil {
-		t.Fatal(err)
-	}
-	if _, err := serial.BuildConfig([]*core.ConfigSource{{Name: path, Format: "json"}}); err != nil {
-		t.Fatal(err)
-	}
-	if program, err := xlua.Compile(alias); program != nil || err == nil || !strings.Contains(err.Error(), "loaded as a configuration file") {
-		t.Fatalf("Compile = %v, %v; want config hard link rejection", program, err)
-	}
-}
-
-func testStdinConfigCannotRunAsLua(t *testing.T, dir string) {
-	path := filepath.Join(dir, "config.lua")
-	if err := os.WriteFile(path, []byte("null = 0\nfunction HandleRoute() end"), 0o600); err != nil {
-		t.Fatal(err)
-	}
-	file, err := os.Open(path)
-	if err != nil {
-		t.Fatal(err)
-	}
-	originalStdin := os.Stdin
-	os.Stdin = file
-	t.Cleanup(func() {
-		os.Stdin = originalStdin
-		file.Close()
-	})
-	if _, err := serial.BuildConfig([]*core.ConfigSource{{Name: "stdin:", Format: "json"}}); err != nil {
-		t.Fatal(err)
-	}
-	if program, err := xlua.Compile(path); program != nil || err == nil || !strings.Contains(err.Error(), "loaded as a configuration file") {
-		t.Fatalf("Compile = %v, %v; want redirected config rejection", program, err)
-	}
-}

main/confloader/external/external.go

@@ -13,7 +13,6 @@ import (
 
 	"github.com/xtls/xray-core/common/buf"
 	"github.com/xtls/xray-core/common/errors"
-	"github.com/xtls/xray-core/common/platform"
 	"github.com/xtls/xray-core/common/utils"
 	"github.com/xtls/xray-core/main/confloader"
 )
@@ -29,15 +28,10 @@ func ConfigLoader(arg string) (out io.Reader, err error) {
 		data, err = FetchHTTPContent(arg)
 
 	case arg == "stdin:":
-		data, err = platform.ReadConfigFile(os.Stdin)
+		data, err = io.ReadAll(os.Stdin)
 
 	default:
-		file, openErr := os.Open(arg)
-		if openErr != nil {
-			return nil, openErr
-		}
-		defer file.Close()
-		data, err = platform.ReadConfigFile(file)
+		data, err = os.ReadFile(arg)
 	}
 
 	if err != nil {