feat(ios): add secure live cloud desktop access

companion/README.md

@@ -29,8 +29,8 @@ upstream hardened its loopback gate.
 
 | | |
 |---|---|
-| **Pairing** | A six-digit code shown on the computer, valid two minutes, five attempts. Redeeming it returns a device token stored only as a SHA-256 digest. |
-| **Authorisation** | Every request needs that token. A rebinding page cannot obtain one. |
+| **Pairing** | A high-entropy QR credential plus a six-digit manual fallback, valid two minutes and single-use. Redeeming either returns a device token stored only as a SHA-256 digest. |
+| **Authorisation** | Every request needs that token. Full cloud-desktop access is a separate per-device capability, off by default. A rebinding page cannot obtain either. |
 | **The allowlist** | Default deny, per method and path (`src/routes.ts`) — the list is every request the app makes, and nothing else. General bot/room PATCH routes stay closed; read state and approval grants use narrow verbs. A route that appears in the harness later is closed to devices until someone adds it here on purpose. |
 | **Scrubbing** | `resumeCursors` — the harness's own provider session ids — never reach a device, whether or not the harness still sends them. |
 | **Discovery** | Bonjour, so a phone finds the computer by name instead of by typed address. |

companion/src/control.ts

@@ -176,6 +176,17 @@ export function createControlServer(options: ControlOptions): Server {
       options.devices.closePairing();
       return json(res, 200, companionState(options));
     }
+    const cloudDesktop = path.match(/^\/devices\/([\w-]+)\/cloud-desktop$/);
+    if (cloudDesktop && (method === "POST" || method === "DELETE")) {
+      try {
+        if (!options.devices.setCloudDesktopAccess(cloudDesktop[1], method === "POST")) {
+          return json(res, 404, { error: "no such device" });
+        }
+      } catch {
+        return json(res, 500, { error: "could not save cloud desktop access" });
+      }
+      return json(res, 200, companionState(options));
+    }
     const revoke = path.match(/^\/devices\/([\w-]+)$/);
     if (revoke && method === "DELETE") {
       if (!options.devices.revoke(revoke[1])) return json(res, 404, { error: "no such device" });
@@ -279,7 +290,9 @@ function render(s) {
     (s.devices.length
       ? "<ul>" + s.devices.map((d) =>
           "<li><div class='grow'><div class=name>" + esc(d.name) + "</div>" +
-          "<div class=dim>Last seen " + ago(d.lastSeenAt) + "</div></div>" +
+          "<div class=dim>Last seen " + ago(d.lastSeenAt) + "</div>" +
+          "<button data-cloud='" + esc(d.id) + "' data-allowed='" + (d.cloudDesktopAccess ? "1" : "0") + "'>" +
+          (d.cloudDesktopAccess ? "Cloud desktop on" : "Allow cloud desktop") + "</button></div>" +
           "<button data-revoke='" + esc(d.id) + "'>Remove</button></li>").join("") + "</ul>"
       : "<p class=dim>No phones are paired yet.</p>");
 
@@ -288,6 +301,12 @@ function render(s) {
   for (const b of document.querySelectorAll("[data-revoke]")) {
     b.addEventListener("click", async () => render(await api("/devices/" + b.dataset.revoke, "DELETE")));
   }
+  for (const b of document.querySelectorAll("[data-cloud]")) {
+    b.addEventListener("click", async () => render(await api(
+      "/devices/" + b.dataset.cloud + "/cloud-desktop",
+      b.dataset.allowed === "1" ? "DELETE" : "POST"
+    )));
+  }
   if (s.pairing) {
     const tick = () => {
       const left = Math.max(0, Math.round((s.pairing.expiresAt - Date.now()) / 1000));

companion/src/devices.ts

@@ -23,6 +23,9 @@ export interface DeviceRecord {
   tokenHash: string;
   createdAt: number;
   lastSeenAt: number;
+  /** Full interactive access to a bot's cloud desktop. Deliberately off on
+   * every new and migrated device until the computer owner enables it. */
+  cloudDesktopAccess: boolean;
 }
 
 /** What the UI is allowed to see: a device without its secret. */
@@ -100,6 +103,7 @@ function normalizeDevice(record: Partial<DeviceRecord> & { id: string; tokenHash
     name: cleanDeviceName(record.name),
     createdAt,
     lastSeenAt: timestamp(record.lastSeenAt, createdAt),
+    cloudDesktopAccess: record.cloudDesktopAccess === true,
   };
 }
 
@@ -209,6 +213,7 @@ export class DeviceRegistry {
       tokenHash: sha256(token),
       createdAt: Date.now(),
       lastSeenAt: Date.now(),
+      cloudDesktopAccess: false,
     };
     this.devices.push(device);
     // Unlike the lastSeenAt write below, this one must not be swallowed. A
@@ -260,6 +265,23 @@ export class DeviceRegistry {
     this.persist();
     return true;
   }
+
+  /** Grant or remove the one capability that crosses from companion actions
+   * into full desktop control. This is per device so a watch-only phone does
+   * not inherit a different phone's permission. */
+  setCloudDesktopAccess(id: string, allowed: boolean): boolean {
+    const device = this.devices.find((candidate) => candidate.id === id);
+    if (!device) return false;
+    const previous = device.cloudDesktopAccess;
+    device.cloudDesktopAccess = allowed;
+    try {
+      this.persist();
+    } catch (error) {
+      device.cloudDesktopAccess = previous;
+      throw error;
+    }
+    return true;
+  }
 }
 
 /**

companion/src/index.ts

@@ -118,7 +118,7 @@ const companion = createServer(
     harnessPort: HARNESS_PORT,
     // `authenticate` also stamps lastSeenAt, which is what makes the control
     // page able to say when a phone was last heard from.
-    authenticate: (token) => Boolean(devices.authenticate(token)),
+    authenticate: (token) => devices.authenticate(token),
     redeem: (code, deviceName) => devices.redeem(code, deviceName),
     serverName: machineName,
   }),

companion/src/proxy.ts

@@ -14,15 +14,15 @@
 import { request as httpRequest, type IncomingMessage, type ServerResponse } from "node:http";
 
 import { bearerToken } from "./devices.ts";
-import { denyReason } from "./routes.ts";
+import { denyReason, isCloudDesktopJoin } from "./routes.ts";
 import { createSseScrubber, isJson, scrub } from "./wire.ts";
 
 /** What the forwarding handler needs from the process around it. */
 export interface ProxyOptions {
   /** Where the harness is listening on loopback. */
   harnessPort: number;
   /** Does this bearer token belong to a paired device? */
-  authenticate: (token: string | undefined) => boolean;
+  authenticate: (token: string | undefined) => { cloudDesktopAccess: boolean } | null;
   /** Redeem a pairing code. Handled here and never forwarded: the harness
    * has no such route and no idea devices exist — pairing is the sidecar's
    * own concern, and the one thing a device does before it has a token. */
@@ -131,17 +131,28 @@ export function createProxyHandler(options: ProxyOptions) {
       return sendJson(res, 403, { error: "forbidden: cross-origin request" });
     }
 
+    const token = bearerToken(req.headers.authorization);
+    const device = options.authenticate(token);
     const denial = denyReason({
       path,
       method,
       // `bearerToken` is the registry's own parser, imported rather than
       // reimplemented: this file used to have a second one, and two parsers
       // that disagree about what a credential looks like means the header a
       // phone sends authenticates on one code path and not the other.
-      authenticated: options.authenticate(bearerToken(req.headers.authorization)),
+      authenticated: Boolean(device),
     });
     if (denial) return sendJson(res, denial.status, { error: denial.error });
 
+    // Pairing a phone grants the ordinary companion surface, not a browser
+    // session with every credential that may exist inside the cloud desktop.
+    // The computer owner enables this capability per device, off by default.
+    if (isCloudDesktopJoin(method, path) && !device?.cloudDesktopAccess) {
+      return sendJson(res, 403, {
+        error: "cloud desktop access is off for this phone — enable it in OpenMausBot → Settings → Companion",
+      });
+    }
+
     // Pairing terminates here. Forwarding it would hand the harness a route
     // it does not have, and the 404 would read to a phone as "wrong address".
     if (method === "POST" && path === "/api/pair") {

companion/src/routes.ts

@@ -32,6 +32,18 @@ export interface RouteRequest {
   authenticated: boolean;
 }
 
+/** The one companion route that crosses into full interactive desktop
+ * control. Both the allowlist and capability gate consume this classifier so
+ * their security decisions cannot drift apart. */
+export const CLOUD_DESKTOP_JOIN_ROUTE = {
+  method: "POST",
+  path: /^\/api\/bots\/[\w-]+\/computer\/join$/,
+} as const;
+
+export function isCloudDesktopJoin(method: string, path: string): boolean {
+  return method === CLOUD_DESKTOP_JOIN_ROUTE.method && CLOUD_DESKTOP_JOIN_ROUTE.path.test(path);
+}
+
 /** Every request the iOS app makes, and nothing else.
  *
  * Ids are `[\w-]+`, matching the harness's own route patterns. The paths
@@ -61,6 +73,9 @@ const ALLOWED: ReadonlyArray<{ method: string; path: RegExp }> = [
   { method: "POST", path: /^\/api\/bots\/[\w-]+\/tasks\/[\w-]+$/ },
   { method: "PATCH", path: /^\/api\/bots\/[\w-]+\/tasks\/[\w-]+$/ },
   { method: "DELETE", path: /^\/api\/bots\/[\w-]+\/tasks\/[\w-]+$/ },
+  // Full cloud desktop access. The route is narrow and the proxy applies a
+  // second, per-device capability check before it reaches the harness.
+  CLOUD_DESKTOP_JOIN_ROUTE,
 
   // rooms
   { method: "POST", path: /^\/api\/groups\/[\w-]+\/messages$/ },

companion/test/control.test.ts

@@ -12,6 +12,7 @@ import { DeviceRegistry } from "../src/devices.ts";
 
 let control: Server;
 let port = 0;
+let devices: DeviceRegistry;
 
 const ask = async (
   method: string,
@@ -28,8 +29,9 @@ const ask = async (
 };
 
 beforeAll(async () => {
+  devices = new DeviceRegistry();
   control = createControlServer({
-    devices: new DeviceRegistry(),
+    devices,
     companionPort: 8810,
     discovery: () => ({ advertising: false, name: "Test computer" }),
   });
@@ -43,6 +45,39 @@ afterAll(async () => {
 });
 
 describe("origins the control server will change state for", () => {
+  it("controls cloud desktop access per paired device", async () => {
+    const { code } = devices.openPairing();
+    const paired = devices.redeem(code, "iPhone");
+    if ("error" in paired) throw new Error(paired.error);
+
+    expect(paired.device.cloudDesktopAccess).toBe(false);
+    expect((await ask("POST", `/devices/${paired.device.id}/cloud-desktop`)).status).toBe(200);
+    expect(devices.authenticate(paired.token)?.cloudDesktopAccess).toBe(true);
+    expect((await ask("DELETE", `/devices/${paired.device.id}/cloud-desktop`)).status).toBe(200);
+    expect(devices.authenticate(paired.token)?.cloudDesktopAccess).toBe(false);
+    expect((await ask("POST", "/devices/missing/cloud-desktop")).status).toBe(404);
+  });
+
+  it("reports a permission write failure without dropping the control server", async () => {
+    const [device] = devices.list();
+    const writable = devices as unknown as { persist: () => void };
+    const persist = writable.persist;
+    writable.persist = () => {
+      throw new Error("ENOSPC: no space left on device");
+    };
+    try {
+      const failed = await ask("POST", `/devices/${device.id}/cloud-desktop`);
+      expect(failed).toEqual({
+        status: 500,
+        body: { error: "could not save cloud desktop access" },
+      });
+      expect(devices.list().find((candidate) => candidate.id === device.id)?.cloudDesktopAccess).toBe(false);
+      expect((await ask("GET", "/state")).status).toBe(200);
+    } finally {
+      writable.persist = persist;
+    }
+  });
+
   it("refuses a state change from a foreign page", async () => {
     // The attack this exists for: a form POST needs no preflight, and the
     // Host header on it is the loopback one this server already approves.

companion/test/devices.test.ts

@@ -60,6 +60,7 @@ describe("DeviceRegistry", () => {
     delete stored.devices[0].name;
     delete stored.devices[0].lastSeenAt;
     delete stored.devices[0].createdAt;
+    delete stored.devices[0].cloudDesktopAccess;
     writeFileSync(file, JSON.stringify(stored));
 
     const reloaded = new DeviceRegistry();
@@ -68,6 +69,7 @@ describe("DeviceRegistry", () => {
     expect(listed.name).toBe("Companion");
     expect(Number.isFinite(listed.lastSeenAt)).toBe(true);
     expect(Number.isFinite(listed.createdAt)).toBe(true);
+    expect(listed.cloudDesktopAccess).toBe(false);
     // and the token it was paired with still works
     expect(reloaded.authenticate(token)?.id).toBe(device.id);
   });
@@ -126,6 +128,31 @@ describe("DeviceRegistry", () => {
     expect(registry.count()).toBe(1);
   });
 
+  it("keeps cloud desktop access off until enabled for that device", () => {
+    const registry = new DeviceRegistry();
+    const { token, device } = pair(registry);
+
+    expect(device.cloudDesktopAccess).toBe(false);
+    expect(registry.authenticate(token)?.cloudDesktopAccess).toBe(false);
+    expect(registry.setCloudDesktopAccess(device.id, true)).toBe(true);
+    expect(registry.authenticate(token)?.cloudDesktopAccess).toBe(true);
+    expect(new DeviceRegistry().authenticate(token)?.cloudDesktopAccess).toBe(true);
+    expect(registry.setCloudDesktopAccess(device.id, false)).toBe(true);
+    expect(registry.authenticate(token)?.cloudDesktopAccess).toBe(false);
+    expect(registry.setCloudDesktopAccess("missing", true)).toBe(false);
+  });
+
+  it("rolls cloud desktop access back when it cannot be saved", () => {
+    const registry = new DeviceRegistry();
+    const { token, device } = pair(registry);
+    (registry as unknown as { persist: () => void }).persist = () => {
+      throw new Error("ENOSPC: no space left on device");
+    };
+
+    expect(() => registry.setCloudDesktopAccess(device.id, true)).toThrow("ENOSPC");
+    expect(registry.authenticate(token)?.cloudDesktopAccess).toBe(false);
+  });
+
   it("uses a high-entropy QR credential and burns the manual fallback with it", () => {
     const registry = new DeviceRegistry();
     const { code, token } = registry.openPairing();

companion/test/proxy-response.test.ts

@@ -23,6 +23,7 @@ const deeplyNested = (() => {
 let harness: Server;
 let sidecar: Server;
 let sidecarPort = 0;
+let cloudDesktopAccess = true;
 /** What the stub harness answers with next. Set per test. */
 let respond: (res: ServerResponse) => void = (res) => res.end();
 
@@ -33,8 +34,9 @@ const close = (server: Server | undefined): Promise<void> =>
   new Promise((resolve) => (server ? server.close(() => resolve()) : resolve()));
 
 /** A request as a paired device makes it. */
-const device = async (path = "/api/bots"): Promise<{ status: number; text: string }> => {
+const device = async (path = "/api/bots", method = "GET"): Promise<{ status: number; text: string }> => {
   const res = await fetch(`http://127.0.0.1:${sidecarPort}${path}`, {
+    method,
     headers: { authorization: `Bearer ${TOKEN}` },
   });
   return { status: res.status, text: await res.text() };
@@ -47,7 +49,7 @@ beforeAll(async () => {
   sidecar = createServer(
     createProxyHandler({
       harnessPort,
-      authenticate: (t) => t === TOKEN,
+      authenticate: (t) => (t === TOKEN ? { cloudDesktopAccess } : null),
       redeem: () => ({ error: "not used here" }),
       serverName: () => "Test computer",
     }),
@@ -61,6 +63,27 @@ afterAll(async () => {
 });
 
 describe("preparing a harness response for a device", () => {
+  it("requires the Mac to enable cloud desktop for this phone", async () => {
+    cloudDesktopAccess = false;
+    try {
+      const { status, text } = await device("/api/bots/b1/computer/join", "POST");
+      expect(status).toBe(403);
+      expect(text).toContain("enable it in OpenMausBot");
+    } finally {
+      cloudDesktopAccess = true;
+    }
+  });
+
+  it("forwards only the enabled device's request for a fresh viewer", async () => {
+    respond = (res) => {
+      res.writeHead(200, { "content-type": "application/json" });
+      res.end(JSON.stringify({ joinUrl: "https://desktop.example/session/fresh", state: "ready" }));
+    };
+    const { status, text } = await device("/api/bots/b1/computer/join", "POST");
+    expect(status).toBe(200);
+    expect(JSON.parse(text).joinUrl).toBe("https://desktop.example/session/fresh");
+  });
+
   it("never forwards a body it could not scrub", async () => {
     // `scrub` recurses once per level, so a deeply nested body throws
     // RangeError while JSON.parse handles it without complaint. That gap is