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fix: bind tunnel registry server to localhost only #296

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Merged
harsha509 merged 1 commit into from
Aug 20, 2026
Merged

fix: bind tunnel registry server to localhost only #296

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10 changes: 6 additions & 4 deletions src/lib/tunnel/tunnel-registry-server.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ import {BaseItem, strongbox} from '@appium/strongbox';
import {TUNNEL_CONTAINER_NAME} from '../../constants.js';
import {getLogger} from '../logger.js';
import type {TunnelRegistry, TunnelRegistryEntry} from '../types.js';
import {MAX_TUNNEL_REGISTRY_WAIT_MS, TUNNEL_REGISTRY_API_BASE_PATH} from './constants.js';
import {MAX_TUNNEL_REGISTRY_WAIT_MS, TUNNEL_REGISTRY_API_BASE_PATH, TUNNEL_REGISTRY_HOST} from './constants.js';
import {isTunnelEntryReady} from './tunnel-availability.js';
import {TunnelReadinessCoordinator} from './tunnel-readiness.js';
import {type RouteRecord, createRouteDispatcher, getRequestPathname} from './tunnel-registry-routes.js';
Expand Down Expand Up @@ -127,10 +127,12 @@ export class TunnelRegistryServer {
await this.handleRequest(req, res);
});

// Start listening
// Start listening on localhost only: the API exposes unauthenticated
// writes (PUT /:udid), so binding all interfaces would let any LAN host
// overwrite tunnel address/port entries.
await new Promise<void>((resolve, reject) => {
this.server?.listen(this.port, () => {
log.info(`Tunnel Registry Server started on port ${this.port}`);
this.server?.listen(this.port, TUNNEL_REGISTRY_HOST, () => {
log.info(`Tunnel Registry Server started on ${TUNNEL_REGISTRY_HOST}:${this.port}`);
log.info(`API available at http://localhost:${this.port}${TUNNEL_REGISTRY_API_BASE_PATH}`);
resolve();
});
Expand Down
64 changes: 51 additions & 13 deletions test/unit/tunnel/tunnel-registry-server.spec.ts
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Original file line number Diff line number Diff line change
@@ -1,4 +1,6 @@
import assert from 'node:assert/strict';
import * as net from 'node:net';
import * as os from 'node:os';
import {afterEach, beforeEach, describe, it} from 'node:test';

import {type TunnelRegistryServer, startTunnelRegistryServer} from '../../../src/lib/tunnel/tunnel-registry-server.js';
Expand Down Expand Up @@ -45,7 +47,7 @@ describe('TunnelRegistryServer', function () {

describe('GET /remotexpc/tunnels', function () {
it('should return all tunnels', async function () {
const response = await fetch(`http://localhost:${testPort}/remotexpc/tunnels`);
const response = await fetch(`http://127.0.0.1:${testPort}/remotexpc/tunnels`);
const data = (await response.json()) as TunnelRegistry;

assert.strictEqual(response.status, 200);
Expand All @@ -57,7 +59,7 @@ describe('TunnelRegistryServer', function () {

describe('GET /remotexpc/tunnels/metadata', function () {
it('should return registry metadata', async function () {
const response = await fetch(`http://localhost:${testPort}/remotexpc/tunnels/metadata`);
const response = await fetch(`http://127.0.0.1:${testPort}/remotexpc/tunnels/metadata`);
const data = (await response.json()) as TunnelRegistry['metadata'] & {
status: string;
};
Expand All @@ -73,7 +75,7 @@ describe('TunnelRegistryServer', function () {

describe('GET /remotexpc/tunnels/:udid', function () {
it('should return tunnel by UDID', async function () {
const response = await fetch(`http://localhost:${testPort}/remotexpc/tunnels/test-udid-123`);
const response = await fetch(`http://127.0.0.1:${testPort}/remotexpc/tunnels/test-udid-123`);
const data = (await response.json()) as TunnelRegistryEntry;

assert.strictEqual(response.status, 200);
Expand All @@ -82,7 +84,7 @@ describe('TunnelRegistryServer', function () {
});

it('should return 404 for non-existent UDID', async function () {
const response = await fetch(`http://localhost:${testPort}/remotexpc/tunnels/non-existent`);
const response = await fetch(`http://127.0.0.1:${testPort}/remotexpc/tunnels/non-existent`);
const data = (await response.json()) as {error: string};

assert.strictEqual(response.status, 404);
Expand Down Expand Up @@ -111,7 +113,7 @@ describe('TunnelRegistryServer', function () {
const pendingServer = await startTunnelRegistryServer(pendingRegistry, pendingPort);

try {
const response = await fetch(`http://localhost:${pendingPort}/remotexpc/tunnels/pending-udid?waitMs=0`);
const response = await fetch(`http://127.0.0.1:${pendingPort}/remotexpc/tunnels/pending-udid?waitMs=0`);
const data = (await response.json()) as {error: string};

assert.strictEqual(response.status, 404);
Expand Down Expand Up @@ -147,7 +149,7 @@ describe('TunnelRegistryServer', function () {

try {
const response = await fetch(
`http://localhost:${refreshPort}/remotexpc/tunnels/refresh-udid/refresh-services`,
`http://127.0.0.1:${refreshPort}/remotexpc/tunnels/refresh-udid/refresh-services`,
{method: 'POST'},
);
const data = (await response.json()) as TunnelRegistryEntry;
Expand All @@ -162,7 +164,7 @@ describe('TunnelRegistryServer', function () {

describe('GET /remotexpc/tunnels/device/:deviceId', function () {
it('should return tunnel by device ID', async function () {
const response = await fetch(`http://localhost:${testPort}/remotexpc/tunnels/device/1`);
const response = await fetch(`http://127.0.0.1:${testPort}/remotexpc/tunnels/device/1`);
const data = (await response.json()) as TunnelRegistryEntry;

assert.strictEqual(response.status, 200);
Expand All @@ -171,7 +173,7 @@ describe('TunnelRegistryServer', function () {
});

it('should return 404 for non-existent device ID', async function () {
const response = await fetch(`http://localhost:${testPort}/remotexpc/tunnels/device/999`);
const response = await fetch(`http://127.0.0.1:${testPort}/remotexpc/tunnels/device/999`);
const data = (await response.json()) as {error: string};

assert.strictEqual(response.status, 404);
Expand All @@ -180,7 +182,7 @@ describe('TunnelRegistryServer', function () {
});

it('should return 400 for invalid device ID', async function () {
const response = await fetch(`http://localhost:${testPort}/remotexpc/tunnels/device/invalid`);
const response = await fetch(`http://127.0.0.1:${testPort}/remotexpc/tunnels/device/invalid`);
const data = (await response.json()) as {error: string};

assert.strictEqual(response.status, 400);
Expand All @@ -196,7 +198,7 @@ describe('TunnelRegistryServer', function () {
rsdPort: 58784,
};

const response = await fetch(`http://localhost:${testPort}/remotexpc/tunnels/test-udid-123`, {
const response = await fetch(`http://127.0.0.1:${testPort}/remotexpc/tunnels/test-udid-123`, {
method: 'PUT',
headers: {'Content-Type': 'application/json'},
body: JSON.stringify(updateData),
Expand All @@ -217,7 +219,7 @@ describe('TunnelRegistryServer', function () {
udid: 'different-udid',
};

const response = await fetch(`http://localhost:${testPort}/remotexpc/tunnels/test-udid-123`, {
const response = await fetch(`http://127.0.0.1:${testPort}/remotexpc/tunnels/test-udid-123`, {
method: 'PUT',
headers: {'Content-Type': 'application/json'},
body: JSON.stringify(updateData),
Expand All @@ -230,7 +232,7 @@ describe('TunnelRegistryServer', function () {
});

it('should return 400 for invalid JSON', async function () {
const response = await fetch(`http://localhost:${testPort}/remotexpc/tunnels/test-udid-123`, {
const response = await fetch(`http://127.0.0.1:${testPort}/remotexpc/tunnels/test-udid-123`, {
method: 'PUT',
headers: {'Content-Type': 'application/json'},
body: 'invalid json',
Expand All @@ -244,11 +246,47 @@ describe('TunnelRegistryServer', function () {

describe('Unknown routes', function () {
it('should return 404 for unknown routes', async function () {
const response = await fetch(`http://localhost:${testPort}/unknown/route`);
const response = await fetch(`http://127.0.0.1:${testPort}/unknown/route`);
const data = (await response.json()) as {error: string};

assert.strictEqual(response.status, 404);
assert.strictEqual(data.error, 'Not found');
});
});

describe('bind address', function () {
it('should only listen on localhost, not on all interfaces', async function () {
// The API exposes unauthenticated writes (PUT /:udid); the server must not
// accept connections arriving on non-loopback interfaces.
// Node reports family as 'IPv4' on some versions and 4 on others
const lanAddress = Object.values(os.networkInterfaces())
.flat()
.find((info) => {
const family = info?.family as string | number | undefined;
return family === 'IPv4' || family === 4 ? !info?.internal : false;
})?.address;
if (!lanAddress) {
// No non-loopback interface on this machine; nothing to probe
return;
}

await new Promise<void>((resolve, reject) => {
const socket = net.connect({host: lanAddress, port: testPort, timeout: 500});
const cleanup = (): void => {
socket.removeAllListeners();
socket.destroy();
};
socket.once('connect', () => {
cleanup();
reject(new Error(`Server unexpectedly accepted a connection on non-loopback address ${lanAddress}`));
});
const onRefusal = (): void => {
cleanup();
resolve();
};
socket.once('error', onRefusal);
socket.once('timeout', onRefusal);
});
});
});
});