Ferndiagnose (MCP): Verbindungscode + abgesicherter Fernzugriff + stdio-Bridge

Neue Funktion, um Diagnose eines laufenden Servers aus der Ferne zu ermoeglichen:
Hilfe -> Remote-Support -> "Ferndiagnose (MCP)". Erzeugt einen Verbindungscode,
den der Assistent nutzt, um Status, Logs, Fehler und Accounts read-only zu lesen.

App-Seite:
- Live (re)startbarer Debug-Server ohne App-Neustart (restartDebugServer wartet auf
  'close' + closeAllConnections, behandelt EADDRINUSE).
- IP-Allowlist (debug_allowlist.txt, exakte IP + CIDR), erzwungen VOR der Auth.
  Fail-closed: Netzwerk-Bind (0.0.0.0) ohne Allowlist akzeptiert nur Loopback.
- One-Click Aktivieren/Aktualisieren/Deaktivieren + Token-Rotation (alter Code sofort
  ungueltig). Sichtbarkeit waehlbar: "Nur lokal" (Tunnel-Empfehlung) vs "Im Netzwerk".
- Verbindungscode rddiag:v1:base64url({v,h,p,t,n?,fp?,s?}); oeffentlicher Host frei
  waehlbar, Netzwerk-IPs als Schnellauswahl.
- Neue IPC: get/enable/disable/rotate Remote-Diagnostics; Controller-Methoden; Typen.

Bridge (tools/rd-diagnostics-mcp, standalone, KEINE App-Dependency):
- stdio MCP-Server (@modelcontextprotocol/sdk) mit 14 Tools, proxyt die bestehende
  HTTP-Debug-API. Multi-Server ueber code/server/RDDIAG_CODE/RDDIAG_SERVERS.
- TLS-Fingerprint-Pinning auf secureConnect (vor Token-Versand), falls https genutzt.
- test/harness.mjs: faehrt einen Fake-Debug-Server hoch und treibt die Bridge als
  echten stdio-Child per JSON-RPC -> voller Protokollpfad gruen.

Sicherheit (Audit): keine persistenten Secrets in den Logs der Debug-API (Passwoerter
redigiert, keine Debrid-Keys/aufgeloesten Download-URLs geloggt; settings/accounts
redigiert). Empfohlener Transport: Loopback + privater Tunnel; Direkt-Bind nur mit
Allowlist in vertrauenswuerdigen Netzen.

Tests: connection-code-Cross-Check (App-Encoder <-> Bridge-Decoder), Allowlist-Matrix
(Loopback, exakt, CIDR, fail-closed, Live-Restart). Volle Suite 905 gruen, tsc=6.

src/main/app-controller.ts

@@ -1,4 +1,5 @@
 import path from "node:path";
+import os from "node:os";
 import v8 from "node:v8";
 import { app } from "electron";
 import { getDebridLinkApiKeyIds } from "../shared/debrid-link-keys";
@@ -9,9 +10,11 @@ import {
   DebridAccountStatus,
   DebridProvider,
   DuplicatePolicy,
+  EnableRemoteDiagnosticsInput,
   HistoryEntry,
   PackagePriority,
   ParsedPackageInput,
+  RemoteDiagnosticsInfo,
   SessionStats,
   StartConflictEntry,
   StartConflictResolutionResult,
@@ -39,7 +42,8 @@ import { MegaWebFallback } from "./mega-web-fallback";
 import { addHistoryEntry, addHistoryEntryForRetention, cancelPendingAsyncSaves, clearHistory, createStoragePaths, loadHistory, loadHistoryForRetention, loadSession, loadSettings, normalizeHistoryEntry, normalizeLoadedSession, normalizeLoadedSessionTransientFields, normalizeSettings, removeHistoryEntry, resetHistoryForRetention, saveHistory, saveSession, saveSettings } from "./storage";
 import { abortActiveUpdateDownload, checkGitHubUpdate, installLatestUpdate } from "./update";
 import { runInstallWithResume } from "./update-install-flow";
-import { rotateDebugToken, startDebugServer, stopDebugServer } from "./debug-server";
+import { rotateDebugToken, startDebugServer, stopDebugServer, restartDebugServer, getDebugServerRuntimeStatus, getActiveDebugToken, getDebugAllowlist, writeDebugServerConfig, clearDebugToken } from "./debug-server";
+import { encodeConnectionCode, loadRemoteMeta, saveRemoteMeta } from "./connection-code";
 import { encryptBackup, decryptBackup } from "./backup-crypto";
 import { buildBackupPayload, planBackupImport } from "./backup-payload";
 import { getAuditLogPath, initAuditLog, logAuditEvent, shutdownAuditLog } from "./audit-log";
@@ -291,6 +295,83 @@ export class AppController {
     return rotated;
   }
 
+  private getSuggestedRemoteHosts(): string[] {
+    const hosts: string[] = [];
+    try {
+      const interfaces = os.networkInterfaces();
+      for (const entry of Object.values(interfaces)) {
+        for (const net of entry || []) {
+          if (net.family === "IPv4" && !net.internal && net.address) {
+            hosts.push(net.address);
+          }
+        }
+      }
+    } catch {
+    }
+    return [...new Set(hosts)];
+  }
+
+  public getRemoteDiagnostics(): RemoteDiagnosticsInfo {
+    const status = getDebugServerRuntimeStatus();
+    const meta = loadRemoteMeta(this.storagePaths.baseDir);
+    const token = getActiveDebugToken();
+    const allowlist = getDebugAllowlist();
+    const suggestedHosts = this.getSuggestedRemoteHosts();
+    const host = meta.publicHost
+      || (status.localOnly ? "127.0.0.1" : (suggestedHosts[0] || status.host));
+    const code = (status.hasToken && token && host)
+      ? encodeConnectionCode({ host, port: status.port, token, name: meta.name || undefined })
+      : null;
+    return {
+      status,
+      code,
+      publicHost: meta.publicHost,
+      name: meta.name,
+      allowlist,
+      suggestedHosts
+    };
+  }
+
+  public async enableRemoteDiagnostics(input: EnableRemoteDiagnosticsInput): Promise<RemoteDiagnosticsInfo> {
+    const baseDir = this.storagePaths.baseDir;
+    const port = input.port && Number.isInteger(input.port) && input.port >= 1024 && input.port <= 65535
+      ? input.port
+      : 9868;
+    const bindHost = input.hostMode === "network" ? "0.0.0.0" : "127.0.0.1";
+    const allowlist = (input.allowlist || []).map((entry) => entry.trim()).filter((entry) => entry.length > 0);
+    if (input.hostMode === "network" && allowlist.length === 0) {
+      throw new Error("Netzwerk-Freigabe erfordert mindestens eine erlaubte IP oder CIDR in der Allowlist.");
+    }
+    let token = getActiveDebugToken();
+    if (!token || input.rotateToken) {
+      token = rotateDebugToken(baseDir).token;
+    }
+    writeDebugServerConfig({ host: bindHost, port, allowlist });
+    saveRemoteMeta(baseDir, { publicHost: (input.publicHost || "").trim(), name: (input.name || "").trim() });
+    await restartDebugServer();
+    this.audit("WARN", "Ferndiagnose aktiviert", {
+      host: bindHost,
+      port,
+      allowlistCount: allowlist.length,
+      localOnly: input.hostMode === "local"
+    });
+    return this.getRemoteDiagnostics();
+  }
+
+  public async disableRemoteDiagnostics(): Promise<RemoteDiagnosticsInfo> {
+    clearDebugToken();
+    await restartDebugServer();
+    this.audit("WARN", "Ferndiagnose deaktiviert (Token entfernt)");
+    return this.getRemoteDiagnostics();
+  }
+
+  public async rotateRemoteDiagnosticsToken(): Promise<RemoteDiagnosticsInfo> {
+    rotateDebugToken(this.storagePaths.baseDir);
+    await restartDebugServer();
+    this.audit("WARN", "Ferndiagnose-Token rotiert");
+    return this.getRemoteDiagnostics();
+  }
+
   public getDebugSetupCheck(): DebugSetupCheckResult {
     return getDebugSetupCheck(this.storagePaths.baseDir);
   }

src/main/connection-code.ts

@@ -0,0 +1,59 @@
+import fs from "node:fs";
+import path from "node:path";
+
+const PREFIX = "rddiag:v1:";
+
+function base64urlEncode(value: string): string {
+  return Buffer.from(value, "utf8")
+    .toString("base64")
+    .replace(/\+/g, "-")
+    .replace(/\//g, "_")
+    .replace(/=+$/, "");
+}
+
+export interface ConnectionCodeInput {
+  host: string;
+  port: number;
+  token: string;
+  name?: string;
+  scheme?: "http" | "https";
+  fingerprint?: string;
+}
+
+export function encodeConnectionCode(input: ConnectionCodeInput): string {
+  const host = String(input.host || "").trim();
+  if (!host) throw new Error("Host fehlt fuer Verbindungscode");
+  const port = Number(input.port);
+  if (!Number.isInteger(port) || port < 1 || port > 65535) throw new Error("Port ungueltig fuer Verbindungscode");
+  if (!input.token) throw new Error("Token fehlt fuer Verbindungscode");
+  const payload: Record<string, unknown> = { v: 1, h: host, p: port, t: input.token };
+  if (input.name) payload.n = String(input.name);
+  if (input.fingerprint) payload.fp = String(input.fingerprint);
+  if (input.scheme && input.scheme !== "http") payload.s = String(input.scheme);
+  return PREFIX + base64urlEncode(JSON.stringify(payload));
+}
+
+export interface RemoteMeta {
+  publicHost: string;
+  name: string;
+}
+
+function remoteMetaPath(baseDir: string): string {
+  return path.join(baseDir, "debug_remote.json");
+}
+
+export function loadRemoteMeta(baseDir: string): RemoteMeta {
+  try {
+    const parsed = JSON.parse(fs.readFileSync(remoteMetaPath(baseDir), "utf8"));
+    return {
+      publicHost: String(parsed.publicHost || ""),
+      name: String(parsed.name || "")
+    };
+  } catch {
+    return { publicHost: "", name: "" };
+  }
+}
+
+export function saveRemoteMeta(baseDir: string, meta: RemoteMeta): void {
+  fs.writeFileSync(remoteMetaPath(baseDir), JSON.stringify({ publicHost: meta.publicHost, name: meta.name }, null, 2), "utf8");
+}

src/main/debug-server.ts

@@ -65,6 +65,16 @@ let authToken = "";
 let bindHost = DEFAULT_HOST;
 let bindPort = DEFAULT_PORT;
 let runtimeBaseDir = "";
+let allowlist: string[] = [];
+
+export interface DebugServerRuntimeStatus {
+  running: boolean;
+  host: string;
+  port: number;
+  hasToken: boolean;
+  localOnly: boolean;
+  allowlistCount: number;
+}
 
 function getStoragePaths() {
   return createStoragePaths(runtimeBaseDir);
@@ -140,6 +150,86 @@ function getHost(baseDir: string): string {
   return DEFAULT_HOST;
 }
 
+function getAllowlistPath(baseDir: string = runtimeBaseDir): string {
+  return path.join(baseDir, "debug_allowlist.txt");
+}
+
+function loadAllowlist(baseDir: string): string[] {
+  try {
+    return fs.readFileSync(getAllowlistPath(baseDir), "utf8")
+      .split(/\r?\n/)
+      .map((line) => line.trim())
+      .filter((line) => line.length > 0 && !line.startsWith("#"));
+  } catch {
+    return [];
+  }
+}
+
+function normalizeIp(ip: string): string {
+  return String(ip || "").trim().replace(/^::ffff:/i, "").toLowerCase();
+}
+
+function isLoopbackIp(ip: string): boolean {
+  const x = normalizeIp(ip);
+  return x === "::1" || x === "localhost" || x.startsWith("127.");
+}
+
+function ipv4ToInt(ip: string): number | null {
+  const parts = ip.split(".");
+  if (parts.length !== 4) {
+    return null;
+  }
+  let result = 0;
+  for (const part of parts) {
+    const value = Number(part);
+    if (!Number.isInteger(value) || value < 0 || value > 255) {
+      return null;
+    }
+    result = (result * 256) + value;
+  }
+  return result >>> 0;
+}
+
+function matchIpRule(clientIp: string, rule: string): boolean {
+  const client = normalizeIp(clientIp);
+  const r = rule.trim().toLowerCase();
+  if (!r) {
+    return false;
+  }
+  if (r === "*" || r === "0.0.0.0/0") {
+    return true;
+  }
+  if (r === client) {
+    return true;
+  }
+  const slash = r.indexOf("/");
+  if (slash > 0) {
+    const baseInt = ipv4ToInt(r.slice(0, slash));
+    const clientInt = ipv4ToInt(client);
+    const bits = Number(r.slice(slash + 1));
+    if (baseInt === null || clientInt === null || !Number.isInteger(bits) || bits < 0 || bits > 32) {
+      return false;
+    }
+    if (bits === 0) {
+      return true;
+    }
+    const mask = bits === 32 ? 0xffffffff : (~((1 << (32 - bits)) - 1)) >>> 0;
+    return (clientInt & mask) === (baseInt & mask);
+  }
+  return false;
+}
+
+function isClientAllowed(clientIp: string): boolean {
+  const client = normalizeIp(clientIp);
+  if (isLoopbackIp(client) || client === "") {
+    return true;
+  }
+  if (allowlist.length === 0) {
+    return false;
+  }
+  return allowlist.some((rule) => matchIpRule(client, rule));
+}
+
 function checkAuth(req: http.IncomingMessage): boolean {
   if (!authToken) {
     return false;
@@ -461,6 +551,18 @@ function handleRequest(req: http.IncomingMessage, res: http.ServerResponse): voi
     return;
   }
 
+  const clientIp = extractDebugClientIp(req);
+  if (!isClientAllowed(clientIp)) {
+    if (traceConfig.enabled && traceConfig.logDebugRequests) {
+      logTraceEvent("WARN", "debug-http", "Durch Allowlist blockiert", {
+        clientIp,
+        url: sanitizeRequestUrlForTrace(req.url || "/")
+      });
+    }
+    jsonResponse(res, 403, { error: "Forbidden", reason: "Client-IP nicht in Allowlist", clientIp });
+    return;
+  }
+
   if (!checkAuth(req)) {
     if (traceConfig.enabled && traceConfig.logDebugRequests) {
       logTraceEvent("WARN", "debug-http", "Unauthorized request", {
@@ -927,32 +1029,126 @@ function handleRequest(req: http.IncomingMessage, res: http.ServerResponse): voi
   });
 }
 
+function openServerSocket(): Promise<void> {
+  return new Promise((resolve) => {
+    authToken = loadToken(runtimeBaseDir);
+    bindPort = getPort(runtimeBaseDir);
+    bindHost = getHost(runtimeBaseDir);
+    allowlist = loadAllowlist(runtimeBaseDir);
+    writeAiManifest(runtimeBaseDir);
+    if (!authToken) {
+      logger.info("Debug-Server: Kein Token in debug_token.txt, Server wird nicht gestartet");
+      resolve();
+      return;
+    }
+    if (bindHost === "0.0.0.0" && allowlist.length === 0) {
+      logger.warn("Debug-Server: Netzwerk-Bind ohne Allowlist - nur Loopback-Clients werden akzeptiert (fail-closed)");
+    }
+    const srv = http.createServer(handleRequest);
+    let settled = false;
+    const settle = (): void => {
+      if (!settled) {
+        settled = true;
+        resolve();
+      }
+    };
+    srv.on("error", (err: NodeJS.ErrnoException) => {
+      if (err.code === "EADDRINUSE") {
+        logger.warn(`Debug-Server: Port ${bindPort} belegt (EADDRINUSE) - Server nicht gestartet`);
+      } else {
+        logger.warn(`Debug-Server Fehler: ${String(err)}`);
+      }
+      if (server === srv) {
+        server = null;
+      }
+      settle();
+    });
+    srv.listen(bindPort, bindHost, () => {
+      logger.info(`Debug-Server gestartet auf ${bindHost}:${bindPort} (Allowlist: ${allowlist.length})`);
+      settle();
+    });
+    server = srv;
+  });
+}
+
 export function startDebugServer(mgr: DownloadManager, baseDir: string): void {
   runtimeBaseDir = baseDir;
-  authToken = loadToken(baseDir);
-  bindPort = getPort(baseDir);
-  bindHost = getHost(baseDir);
-  writeAiManifest(baseDir);
-  if (!authToken) {
-    logger.info("Debug-Server: Kein Token in debug_token.txt, Server wird nicht gestartet");
-    return;
-  }
-
   manager = mgr;
+  void openServerSocket();
+}
 
-  server = http.createServer(handleRequest);
-  server.listen(bindPort, bindHost, () => {
-    logger.info(`Debug-Server gestartet auf ${bindHost}:${bindPort}`);
-  });
-  server.on("error", (err) => {
-    logger.warn(`Debug-Server Fehler: ${String(err)}`);
+export async function restartDebugServer(): Promise<DebugServerRuntimeStatus> {
+  const old = server;
+  if (old) {
     server = null;
-  });
+    await new Promise<void>((resolve) => {
+      let settled = false;
+      const done = (): void => {
+        if (!settled) {
+          settled = true;
+          resolve();
+        }
+      };
+      old.close(() => done());
+      try {
+        old.closeAllConnections?.();
+      } catch {
+      }
+      setTimeout(done, 1500);
+    });
+  }
+  await openServerSocket();
+  return getDebugServerRuntimeStatus();
+}
+
+export function getDebugServerRuntimeStatus(): DebugServerRuntimeStatus {
+  return {
+    running: Boolean(server && server.listening),
+    host: bindHost,
+    port: bindPort,
+    hasToken: Boolean(authToken),
+    localOnly: isLoopbackIp(bindHost) || bindHost === "127.0.0.1",
+    allowlistCount: allowlist.length
+  };
+}
+
+export function getActiveDebugToken(): string {
+  return authToken || loadToken(runtimeBaseDir);
+}
+
+export function getDebugAllowlist(): string[] {
+  return [...allowlist];
+}
+
+export function writeDebugServerConfig(opts: { host?: string; port?: number; allowlist?: string[] }): void {
+  if (opts.host !== undefined) {
+    fs.writeFileSync(path.join(runtimeBaseDir, "debug_host.txt"), `${opts.host}\n`, "utf8");
+  }
+  if (opts.port !== undefined) {
+    fs.writeFileSync(path.join(runtimeBaseDir, "debug_port.txt"), `${opts.port}\n`, "utf8");
+  }
+  if (opts.allowlist !== undefined) {
+    const body = opts.allowlist.length > 0 ? opts.allowlist.join("\n") + "\n" : "";
+    fs.writeFileSync(getAllowlistPath(), body, "utf8");
+  }
+}
+
+export function clearDebugToken(): void {
+  try {
+    fs.unlinkSync(getDebugTokenPath());
+  } catch {
+  }
+  authToken = "";
+  writeAiManifest(runtimeBaseDir);
 }
 
 export function stopDebugServer(): void {
   if (server) {
     server.close();
+    try {
+      server.closeAllConnections?.();
+    } catch {
+    }
     server = null;
     logger.info("Debug-Server gestoppt");
   }

src/main/main.ts

@@ -1,7 +1,7 @@
 import fs from "node:fs";
 import path from "node:path";
 import { app, BrowserWindow, clipboard, dialog, ipcMain, IpcMainInvokeEvent, Menu, shell, Tray } from "electron";
-import { AddLinksPayload, AppSettings, DebridProvider, UpdateInstallProgress } from "../shared/types";
+import { AddLinksPayload, AppSettings, DebridProvider, EnableRemoteDiagnosticsInput, UpdateInstallProgress } from "../shared/types";
 import { AppController } from "./app-controller";
 import { IPC_CHANNELS } from "../shared/ipc";
 import { getLogFilePath, logger } from "./logger";
@@ -671,6 +671,33 @@ function registerIpcHandlers(): void {
     return { path: rotated.path };
   });
 
+  ipcMain.handle(IPC_CHANNELS.GET_REMOTE_DIAGNOSTICS, async () => {
+    return controller.getRemoteDiagnostics();
+  });
+
+  ipcMain.handle(IPC_CHANNELS.ENABLE_REMOTE_DIAGNOSTICS, async (_event: IpcMainInvokeEvent, input: EnableRemoteDiagnosticsInput) => {
+    if (!input || (input.hostMode !== "local" && input.hostMode !== "network")) {
+      throw new Error("hostMode muss 'local' oder 'network' sein");
+    }
+    const allowlist = Array.isArray(input.allowlist) ? input.allowlist.map((entry) => String(entry)) : [];
+    return controller.enableRemoteDiagnostics({
+      hostMode: input.hostMode,
+      publicHost: String(input.publicHost || ""),
+      port: input.port ? Number(input.port) : undefined,
+      allowlist,
+      name: input.name ? String(input.name) : undefined,
+      rotateToken: Boolean(input.rotateToken)
+    });
+  });
+
+  ipcMain.handle(IPC_CHANNELS.DISABLE_REMOTE_DIAGNOSTICS, async () => {
+    return controller.disableRemoteDiagnostics();
+  });
+
+  ipcMain.handle(IPC_CHANNELS.ROTATE_REMOTE_DIAGNOSTICS_TOKEN, async () => {
+    return controller.rotateRemoteDiagnosticsToken();
+  });
+
   ipcMain.handle(IPC_CHANNELS.OPEN_ITEM_LOG, async (_event: IpcMainInvokeEvent, itemId: string) => {
     validateString(itemId, "itemId");
     const logPath = controller.getItemLogPath(itemId);