feat(插件代理): 同源反向代理 —— VNC 不再暴露额外端口

问题：登录返回的 view_url 是 http://127.0.0.1:60100/vnc.html，WebUI 直接把它
嵌进 iframe。远程运维打开必白屏 —— 127.0.0.1 在客户端指向客户端自己，且
websockify/x11vnc 只绑回环，换服务器 IP 也连不上（实测 LAN IP 访问 000）。

★ 教训：只验证"服务端截图有画面"就宣布 VNC 可用是不充分的。四层链路里
①X 渲染 ②noVNC 客户端渲染 一直是好的，白屏真因在第④层「客户端如何拿到地址」。

内核新增通用「插件前缀代理」能力（不是为 channels 写的专用反向代理）：
- plugin.http 支持 prefix = true：声明前缀路由，承接所有子路径
- handler 返回 { proxy = "http://127.0.0.1:PORT" }，内核每次请求都问一遍
  ⇒ 会话停止/过期后插件不再给目标，旧地址自然失效（撤销点唯一）
- 鉴权与角色门禁复用现有链路，无旁路
- statusRecorder 增加 Unwrap()，让 Hijack 穿透访问日志中间件（否则 WebSocket 升级失败）
- 目标只允许带显式端口的**字面回环 IP**（用户拍板方案 A）：拒绝 https、localhost
  主机名、无端口、带 userinfo/path/query；理由是主机名可能被 hosts/DNS 改写
- 拒绝跨站 Origin（WebSocket 带环境 Cookie，否则第三方网页可借管理员会话开隧道）
- 不向插件后端转发 Authorization/Cookie/api_key

channels 接入：
- 新增 channels/browser/proxy/:session（prefix=true）
- 会话代号 = seq-随机8位，防猜到活跃会话
- view_url 改为网关同源路径，noVNC 的 WebSocket 走同前缀 /websockify
- 会话过期即回收浏览器栈并返回 404

判据（每条咬真实外部效应）：
- 静态资源转发
- 真实 HTTP 101 升级 + 双向数据回传（只断言静态转发不够 —— 升级是白屏真考点）
- 网关凭据不泄漏（在服务端断言请求头）
- 非法目标全拒（公网/localhost/https/无端口/带 path、query、userinfo）
- 跨站 Origin 403
- 未鉴权 401、过期会话 404、非子路径 404

回归：go test -tags luajit ./... 9 包全绿

internal/core/channels_vnc_test.go

@@ -53,8 +53,8 @@ func TestChannelsVncStackEndToEnd(t *testing.T) {
 		t.Fatalf("浏览器栈未能启动: %s", e)
 	}
 	view, _ := m["view_url"].(string)
-	if !strings.Contains(view, "vnc.html") {
-		t.Fatalf("应给出 noVNC 内嵌地址, 实得 %q", view)
+	if !strings.HasPrefix(view, "/api/plugins/http/channels/browser/proxy/") || !strings.Contains(view, "vnc.html") {
+		t.Fatalf("应给出同源 noVNC 内嵌地址，不能让远程客户端连服务器回环端口, 实得 %q", view)
 	}
 	sess := m["session"].(map[string]interface{})
 	if sess["cdp_port"] == nil {

internal/gateway/plugin_http_routes.go

@@ -55,6 +55,15 @@ func (g *Gateway) handlePluginHTTP(w http.ResponseWriter, r *http.Request) {
 	for i := range matches {
 		h := matches[i]
 		p, ok := matchHandlerPath(h.Path, rest)
+		if h.Prefix {
+			pattern := strings.Trim(h.Path, "/")
+			parts := strings.Split(strings.Trim(rest, "/"), "/")
+			n := len(strings.Split(pattern, "/"))
+			ok = len(parts) >= n
+			if ok {
+				p, ok = matchHandlerPath(pattern, strings.Join(parts[:n], "/"))
+			}
+		}
 		if !ok {
 			continue
 		}
@@ -116,6 +125,16 @@ func (g *Gateway) handlePluginHTTP(w http.ResponseWriter, r *http.Request) {
 		writeError(w, http.StatusBadGateway, "plugin_error", err.Error())
 		return
 	}
+	if resp.Proxy != "" {
+		if !chosen.Prefix {
+			writeError(w, http.StatusBadGateway, "plugin_error", "proxy response requires prefix=true")
+			return
+		}
+		parts := strings.Split(strings.Trim(rest, "/"), "/")
+		n := len(strings.Split(strings.Trim(chosen.Path, "/"), "/"))
+		g.servePluginProxy(w, r, resp.Proxy, pluginHTTPPrefix+strings.Join(parts[:n], "/"))
+		return
+	}
 	lua.WriteHandlerResponse(w, resp)
 }
 

internal/gateway/plugin_proxy.go

@@ -0,0 +1,54 @@
+package gateway
+
+import (
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"strings"
+)
+
+// servePluginProxy forwards a plugin-owned prefix to an explicit loopback
+// origin. No destination or path may be supplied by the client. Authentication
+// and endpoint authorization have already completed before this is called.
+func (g *Gateway) servePluginProxy(w http.ResponseWriter, r *http.Request, target, prefix string) {
+	u, err := url.Parse(target)
+	if err != nil || u.Scheme != "http" || u.User != nil || u.RawQuery != "" || u.Fragment != "" || (u.Path != "" && u.Path != "/") {
+		writeError(w, http.StatusBadGateway, "plugin_proxy", "proxy must name a loopback HTTP origin")
+		return
+	}
+	ip := net.ParseIP(u.Hostname())
+	if ip == nil || !ip.IsLoopback() || u.Port() == "" {
+		writeError(w, http.StatusBadGateway, "plugin_proxy", "proxy requires a literal loopback address and port")
+		return
+	}
+	// WebSocket requests are browser-initiated and carry ambient cookies. Do not
+	// allow a foreign website to use an administrator's session to open a tunnel.
+	if origin := r.Header.Get("Origin"); origin != "" {
+		o, e := url.Parse(origin)
+		if e != nil || !strings.EqualFold(o.Host, r.Host) {
+			writeError(w, http.StatusForbidden, "forbidden", "cross-origin proxy request refused")
+			return
+		}
+	}
+	proxy := httputil.NewSingleHostReverseProxy(u)
+	director := proxy.Director
+	proxy.Director = func(out *http.Request) {
+		director(out)
+		out.URL.Path = strings.TrimPrefix(r.URL.Path, prefix)
+		if out.URL.Path == "" {
+			out.URL.Path = "/"
+		}
+		out.URL.RawPath = ""
+		out.Host = u.Host
+		out.Header.Del("Authorization")
+		out.Header.Del("Cookie")
+		q := out.URL.Query()
+		q.Del("api_key")
+		out.URL.RawQuery = q.Encode()
+	}
+	proxy.ErrorHandler = func(w http.ResponseWriter, r *http.Request, err error) {
+		writeError(w, http.StatusBadGateway, "plugin_proxy", "plugin service unavailable")
+	}
+	proxy.ServeHTTP(w, r)
+}

internal/gateway/plugin_proxy_security_test.go

@@ -0,0 +1,66 @@
+package gateway
+
+import (
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestPluginProxyRejectsUnsafeTargetsAndOrigin(t *testing.T) {
+	g, _ := gatewayWithSpy(t)
+	for _, target := range []string{"http://example.com:80", "http://localhost:80", "https://127.0.0.1:80", "http://127.0.0.1", "http://u:p@127.0.0.1:80", "http://127.0.0.1:80/path", "http://127.0.0.1:80/?x=1"} {
+		rr := httptest.NewRecorder()
+		g.servePluginProxy(rr, httptest.NewRequest("GET", "http://gateway/api/plugins/http/relay/s/live.js", nil), target, "/api/plugins/http/relay/s")
+		if rr.Code != 502 {
+			t.Errorf("unsafe target %q accepted: %d", target, rr.Code)
+		}
+	}
+	rr := httptest.NewRecorder()
+	req := httptest.NewRequest("GET", "http://gateway/api/plugins/http/relay/s/websockify", nil)
+	req.Header.Set("Origin", "https://evil.example")
+	g.servePluginProxy(rr, req, "http://127.0.0.1:12345", "/api/plugins/http/relay/s")
+	if rr.Code != 403 {
+		t.Fatalf("foreign origin accepted: %d", rr.Code)
+	}
+}
+
+func TestPluginPrefixProxyAuthorizationAndRevocation(t *testing.T) {
+	backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { t.Error("denied request reached backend") }))
+	defer backend.Close()
+	g, _ := gatewayWithSpy(t)
+	src := `local p={name="relaydeny",http={{path="relaydeny/:session",prefix=true,roles={"admin"},handler="proxy"}}}
+ function p.proxy(req) return {status=404,body="expired session"} end
+ return p`
+	if err := g.core.Plugins().LoadSource("relaydeny", src); err != nil {
+		t.Fatal(err)
+	}
+	server := httptest.NewServer(g.Handler())
+	defer server.Close()
+	for _, tc := range []struct {
+		path, key string
+		status    int
+	}{
+		{"/api/plugins/http/relaydeny/expired/vnc.html", "", 401},
+		{"/api/plugins/http/relaydeny/expired/vnc.html", "sk-test", 404},
+		{"/api/plugins/http/relaydeny-not-a-child/expired/vnc.html", "sk-test", 404},
+	} {
+		req, _ := http.NewRequest("GET", server.URL+tc.path, nil)
+		if tc.key != "" {
+			req.Header.Set("Authorization", "Bearer "+tc.key)
+		}
+		resp, err := http.DefaultClient.Do(req)
+		if err != nil {
+			t.Fatal(err)
+		}
+		b, _ := io.ReadAll(resp.Body)
+		resp.Body.Close()
+		if resp.StatusCode != tc.status {
+			t.Fatalf("%s got %d %s", tc.path, resp.StatusCode, b)
+		}
+		if tc.key != "" && strings.Contains(tc.path, "/expired/") && strings.Contains(tc.path, "/relaydeny/") && string(b) != "expired session" {
+			t.Fatalf("revocation response=%s", b)
+		}
+	}
+}

internal/gateway/plugin_proxy_test.go

@@ -0,0 +1,82 @@
+package gateway
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+// Drive the real authenticated plugin route, including the access-log wrapper.
+// A successful static request alone does not prove WebSocket can upgrade.
+func TestPluginPrefixProxyHTTPAndUpgrade(t *testing.T) {
+	backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Header.Get("Authorization") != "" || r.Header.Get("Cookie") != "" || r.URL.Query().Get("api_key") != "" {
+			t.Error("gateway credentials leaked to plugin backend")
+		}
+		if r.URL.Path == "/websockify" {
+			c, b, err := w.(http.Hijacker).Hijack()
+			if err != nil {
+				t.Error(err)
+				return
+			}
+			defer c.Close()
+			fmt.Fprint(b, "HTTP/1.1 101 Switching Protocols\r\nConnection: Upgrade\r\nUpgrade: websocket\r\n\r\n")
+			b.Flush()
+			io.Copy(c, c)
+			return
+		}
+		fmt.Fprint(w, r.URL.Path+"?"+r.URL.RawQuery)
+	}))
+	defer backend.Close()
+	g, _ := gatewayWithSpy(t)
+	src := fmt.Sprintf(`local p={name="relay",http={{path="relay/:session",prefix=true,method="GET",roles={"admin"},handler="proxy"}}}
+ function p.proxy(req)
+ if req.params.session ~= "live" then return {status=404,body="expired"} end
+ return {proxy=%q}
+ end
+ return p`, backend.URL)
+	if err := g.core.Plugins().LoadSource("relay", src); err != nil {
+		t.Fatal(err)
+	}
+	server := httptest.NewServer(g.Handler())
+	defer server.Close()
+	req, _ := http.NewRequest("GET", server.URL+"/api/plugins/http/relay/live/app/main.js?x=1&api_key=sk-test", nil)
+	req.Header.Set("Authorization", "Bearer sk-test")
+	req.AddCookie(&http.Cookie{Name: "gw_key", Value: "sk-test"})
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		t.Fatal(err)
+	}
+	body, _ := io.ReadAll(resp.Body)
+	resp.Body.Close()
+	if resp.StatusCode != 200 || string(body) != "/app/main.js?x=1" {
+		t.Fatalf("HTTP proxy: %d %s", resp.StatusCode, body)
+	}
+	c, err := net.Dial("tcp", strings.TrimPrefix(server.URL, "http://"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+	fmt.Fprintf(c, "GET /api/plugins/http/relay/live/websockify HTTP/1.1\r\nHost: %s\r\nAuthorization: Bearer sk-test\r\nConnection: Upgrade\r\nUpgrade: websocket\r\n\r\n", strings.TrimPrefix(server.URL, "http://"))
+	b := bufio.NewReader(c)
+	reply, err := http.ReadResponse(b, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if reply.StatusCode != 101 {
+		t.Fatalf("upgrade failed: %s", reply.Status)
+	}
+	c.Write([]byte("ping"))
+	got := make([]byte, 4)
+	if _, err = io.ReadFull(b, got); err != nil {
+		t.Fatal(err)
+	}
+	if string(got) != "ping" {
+		t.Fatalf("tunnel payload=%q", got)
+	}
+}

internal/gateway/server.go

@@ -187,6 +187,10 @@ type statusRecorder struct {
 	code int
 }
 
+// Unwrap preserves optional writer capabilities (notably Hijack for WebSocket)
+// through the access-log middleware via http.ResponseController.
+func (s *statusRecorder) Unwrap() http.ResponseWriter { return s.ResponseWriter }
+
 func (s *statusRecorder) WriteHeader(code int) {
 	if s.code == 0 {
 		s.code = code

internal/lua/plugin_http_handler.go

@@ -100,6 +100,8 @@ type handlerRequest struct {
 
 // handlerResponse is what a Lua handler returns.
 type handlerResponse struct {
+	// Proxy is a loopback HTTP origin. The gateway owns streaming and upgrades.
+	Proxy   string
 	Status  int
 	Headers map[string]string
 	Body    string
@@ -180,6 +182,9 @@ func parseHandlerResponse(v interface{}) (*handlerResponse, error) {
 			return nil, fmt.Errorf("status must be a number, got %T", s)
 		}
 	}
+	if target, ok := m["proxy"].(string); ok {
+		out.Proxy = target
+	}
 	if b, ok := m["body"].(string); ok {
 		out.Body = b
 	}
@@ -196,9 +201,9 @@ func parseHandlerResponse(v interface{}) (*handlerResponse, error) {
 	// return. A table carrying ONLY a status is not: `{status=204}` is the normal
 	// way to answer with no body, and treating it as an error would make the
 	// correct spelling unusable.
-	if out.Body == "" && out.JSON == nil && out.Headers == nil && len(m) == 0 {
+	if out.Body == "" && out.JSON == nil && out.Headers == nil && out.Proxy == "" && len(m) == 0 {
 		return nil, fmt.Errorf("handler returned an empty table; return " +
-			"{status=…, body=…}, {status=…, json=…}, or {status=…} for no body")
+			"{status=…, body=…}, {status=…, json=…}, {status=…, proxy=…}, or {status=…} for no body")
 	}
 	return out, nil
 }

internal/lua/plugins.go

@@ -2359,6 +2359,8 @@ type HTTPHandler struct {
 	// Path is the route suffix under /api/plugins/http/. It may contain ":name"
 	// segments, captured into request.params.
 	Path string `json:"path"`
+	// Prefix claims this path and its descendants for a streaming proxy handler.
+	Prefix bool `json:"prefix,omitempty"`
 	// Method is the HTTP method; "" or GET. Only GET/POST/PUT/DELETE/PATCH are
 	// accepted — an arbitrary verb would need a switch in the router for no gain.
 	Method string `json:"method,omitempty"`
@@ -2483,7 +2485,7 @@ func readPluginHTTP(L *golua.State) []HTTPHandler {
 			continue
 		}
 		ctx.strictKeys(h, "http[]", "path", "method", "handler", "description",
-			"roles", "keys", "public")
+			"roles", "keys", "public", "prefix")
 		dh := HTTPHandler{
 			Path:        decString(h, "path"),
 			Method:      decString(h, "method"),
@@ -2504,6 +2506,9 @@ func readPluginHTTP(L *golua.State) []HTTPHandler {
 			}
 			dh.Handler = name
 		}
+		if p, ok := h["prefix"].(bool); ok {
+			dh.Prefix = p
+		}
 		if p, ok := h["public"].(bool); ok {
 			dh.Public = p
 		}

internal/lua/plugins/channels.lua

@@ -4269,11 +4269,22 @@ local function spawnBrowser(start_url)
     return nil, "浏览器 CDP 无应答（:" .. tostring(cdpPort) .. "）：" .. tostring(why)
   end
   b.pids = pids
-  b.session = { display = disp, vnc = vport, ws = wport, cdp = cdpPort, pass = pass, seq = seq }
-  local host = (plugin.state.settings and plugin.state.settings.vnc_host) or "127.0.0.1"
+  -- 同源代理不再需要 vnc_host；后端仍只监听回环。
+  local sess = tostring(seq) .. "-" .. pass:sub(1, 8)
+  b.session = { display = disp, vnc = vport, ws = wport, cdp = cdpPort, pass = pass, seq = seq, sess = sess,
+    expires_at = (os.time and os.time() or 0) + 900 }
+  -- 代理入口：把 noVNC 视图路径经网关回传，而不是让客户端去连 VNC 端口。
+  -- 客户端可能来自另一台机器（127.0.0.1 指向客户端自己）且 websockify 只绑回环，
+  -- 所以只能由网关同端口转发；插件只提供回环目标与绝对路径，不处理传输。
+  local base = "/api/plugins/http/channels/browser/proxy/" .. sess
+  local proxyPath = base .. "/vnc.html?autoconnect=1&resize=scale&password=" .. pass
+    .. "&path=" .. urlencode(base:sub(2) .. "/websockify")
   return {
-    view_url = ("http://%s:%d/vnc.html?autoconnect=1&host=%s&port=%d&password=%s"):format(
-      host, wport, host, wport, pass),
+    view_url = proxyPath,
+    proxy_path = proxyPath,
+    proxy_url = base .. "/vnc.html",
+    session_id = sess,
+    vnc_target = ("http://127.0.0.1:%d"):format(wport),
     password = pass,
     cdp_port = cdpPort,
     display = disp,
@@ -6251,6 +6262,9 @@ plugin.http = {
     roles = { "admin" }, description = "浏览器栈依赖预检（缺什么、装哪个包）" },
   { path = "channels/browser/status", method = "GET", handler = "browser_status",
     roles = { "admin" }, description = "服务端浏览器会话状态" },
+  { path = "channels/browser/proxy/:session", method = "GET", prefix = true,
+    handler = "browser_proxy", roles = { "admin" },
+    description = "把会话的 noVNC 静态资源与 WebSocket 经网关同端口转发（不暴露 VNC 端口）" },
   { path = "channels/browser/collect", method = "POST", handler = "collect_credentials",
     roles = { "admin" }, description = "从服务端浏览器取凭据（CDP）" },
   { path = "channels/browser/stop", method = "POST", handler = "stop_browser",
@@ -7485,6 +7499,24 @@ function plugin.browser_status(req)
   return { status = 200, json = { ok = true, running = s ~= nil, session = s } }
 end
 
+-- browser_proxy：前缀代理的每次请求入口。
+-- 只回答「当前会话的回环目标」；回收后 session 为空，地址即失效（404），
+-- 未运行的会话 id 也不会被转发（防目录穿越与跨会话探测）。
+function plugin.browser_proxy(req)
+  sweepSessions()
+  local b = browserStack()
+  local s = b.session
+  local want = req and req.params and req.params.session or nil
+  if s and s.expires_at and s.expires_at <= os.time() then
+    reapBrowser()
+    s = nil
+  end
+  if not s or not s.ws or not s.sess or s.sess ~= want then
+    return { status = 404, json = { error = "没有这个浏览器会话" } }
+  end
+  return { proxy = ("http://127.0.0.1:%d"):format(s.ws) }
+end
+
 function plugin.inject_platforms(req)
   local args = bodyOf(req)
   if args.platforms == nil then args = req end