Files
UNITRONIX abc00b8804 feat(guest): enforce scoped guest access lifecycle
Bind guest WebSocket sessions to a single target peer, enforce grant lifecycle and atomic usage, add the guest issuer scope, and document the password-less security boundary.\n\nRefs #440\n\nThanks: INSOLVE (Honorary); Marco Jakobs (@jacotec); MyNameisStitch (@MyNameisStitch); Redspin (@playerumpknow)
2026-10-03 10:22:20 +02:00

676 lines
28 KiB
JavaScript

/**
* BetterDesk Console - WebSocket Relay Proxy
* Bridges browser WebSocket connections to TCP connections for hbbs/hbbr
*
* Provides two WebSocket endpoints:
* /ws/rendezvous - proxies to hbbs TCP (port 21116)
* /ws/relay - proxies to hbbr TCP (port 21117)
*
* IMPORTANT: hbbr treats loopback TCP connections as admin command interface
* (relay_server.rs: `if !ws && ip.is_loopback()`). The relay proxy must
* connect via a non-loopback IP so hbbr handles it as a relay request.
*/
const WebSocket = require('ws');
const net = require('net');
const os = require('os');
const path = require('path');
const protobuf = require('protobufjs');
const config = require('../config/config');
const { enforceOrigin } = require('../middleware/wsOrigin');
const { roleHasPermission } = require('../middleware/auth');
const { registerUpgradeHandler } = require('./wsUpgradeRouter');
// Maximum concurrent relay connections per IP
const MAX_CONNECTIONS_PER_IP = 5;
// Connection timeout (no data for 2 minutes = close)
const IDLE_TIMEOUT_MS = 120000;
// RustDesk desktop frames can exceed the small control-message limit.
const MAX_RELAY_FRAME_SIZE = 64 * 1024 * 1024;
const GUEST_REVALIDATION_INTERVAL_MS = 15000;
// grant_id → active bridge cleanup callbacks. This is intentionally local for
// immediate revocation in the current panel process; each bridge also
// revalidates against Go so revocations made by another process are enforced.
const activeGuestBridges = new Map();
const guestSessionStates = new Map();
let rendezvousType = null;
function getRendezvousType() {
if (!rendezvousType) {
const root = protobuf.loadSync(path.join(__dirname, '../protos/rendezvous.proto'));
rendezvousType = root.lookupType('hbb.RendezvousMessage');
}
return rendezvousType;
}
function decodeRendezvousPayload(payload) {
try {
return getRendezvousType().decode(payload);
} catch {
return null;
}
}
function guestTargetMatches(message, peerId) {
if (!message || !peerId) return false;
const request = message.punchHoleRequest || message.requestRelay;
return !request || String(request.id || '') === peerId;
}
function registerGuestBridge(grantId, cleanup) {
if (!grantId || typeof cleanup !== 'function') return () => {};
let bridges = activeGuestBridges.get(grantId);
if (!bridges) {
bridges = new Set();
activeGuestBridges.set(grantId, bridges);
}
bridges.add(cleanup);
return () => {
bridges.delete(cleanup);
if (bridges.size === 0) activeGuestBridges.delete(grantId);
};
}
function invalidateGuestGrant(grantId) {
const normalizedId = String(grantId || '');
const bridges = activeGuestBridges.get(normalizedId);
for (const key of guestSessionStates.keys()) {
if (key.startsWith(`${normalizedId}\0`)) guestSessionStates.delete(key);
}
if (!bridges) return 0;
for (const cleanup of [...bridges]) cleanup('guest-grant-revoked');
return bridges.size;
}
async function consumeGuestSession(grant, token, peerId, sessionId) {
const key = `${grant.id || 'unknown'}\0${sessionId}`;
const existing = guestSessionStates.get(key);
if (existing) return existing;
const pending = (async () => {
const betterdeskApi = require('./betterdeskApi');
await betterdeskApi.apiClient.post('/guest/access-links/consume', {
token,
peer_id: peerId,
});
const expiresAt = new Date(grant.expires_at).getTime();
const lifetime = Number.isFinite(expiresAt)
? Math.max(1000, expiresAt - Date.now())
: GUEST_REVALIDATION_INTERVAL_MS;
setTimeout(() => guestSessionStates.delete(key), lifetime).unref?.();
return true;
})();
guestSessionStates.set(key, pending);
try {
return await pending;
} catch (err) {
guestSessionStates.delete(key);
throw err;
}
}
function encodeRelayFrame(data) {
const payload = Buffer.isBuffer(data) ? data : Buffer.from(data);
const len = payload.length;
// RustDesk BytesCodec uses a single 0x00 header for a valid empty
// payload. Empty frames are meaningful for raw relay data (for example
// empty file blocks) and must not be confused with an invalid protobuf
// control frame.
if (len > MAX_RELAY_FRAME_SIZE) {
throw new Error(`invalid relay frame size: ${len}`);
}
let header;
if (len <= 0x3F) {
header = Buffer.from([len << 2]);
} else if (len <= 0x3FFF) {
header = Buffer.allocUnsafe(2);
header.writeUInt16LE((len << 2) | 0x01);
} else if (len <= 0x3FFFFF) {
const value = (len * 4) + 0x02;
header = Buffer.allocUnsafe(3);
header[0] = value & 0xFF;
header[1] = (value >>> 8) & 0xFF;
header[2] = (value >>> 16) & 0xFF;
} else {
header = Buffer.allocUnsafe(4);
header.writeUInt32LE(((len * 4) + 0x03) >>> 0);
}
return Buffer.concat([header, payload], header.length + len);
}
function createRelayFrameDecoder() {
let buffer = Buffer.alloc(0);
let dataLen = 0;
return {
feed(chunk) {
const incoming = Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk);
const needed = dataLen + incoming.length;
if (needed > MAX_RELAY_FRAME_SIZE + 4) {
throw new Error('relay frame buffer exceeds maximum size');
}
if (needed > buffer.length) {
const capacity = Math.min(
MAX_RELAY_FRAME_SIZE + 4,
Math.max(needed, buffer.length * 2, 4096)
);
const grown = Buffer.allocUnsafe(capacity);
if (dataLen > 0) buffer.copy(grown, 0, 0, dataLen);
buffer = grown;
}
incoming.copy(buffer, dataLen);
dataLen += incoming.length;
const frames = [];
let offset = 0;
while (offset < dataLen) {
const headerLen = (buffer[offset] & 0x03) + 1;
if (dataLen - offset < headerLen) break;
let encoded = 0;
for (let i = 0; i < headerLen; i++) {
encoded += buffer[offset + i] * (2 ** (8 * i));
}
const payloadLen = Math.floor(encoded / 4);
if (payloadLen > MAX_RELAY_FRAME_SIZE) {
throw new Error(`invalid relay payload length: ${payloadLen}`);
}
if (dataLen - offset - headerLen < payloadLen) break;
const start = offset + headerLen;
frames.push(Buffer.from(buffer.subarray(start, start + payloadLen)));
offset = start + payloadLen;
}
if (offset > 0) {
const remaining = dataLen - offset;
if (remaining > 0) buffer.copy(buffer, 0, offset, dataLen);
dataLen = remaining;
}
if (dataLen === 0 && buffer.length > 1024 * 1024) buffer = Buffer.alloc(0);
return frames;
},
};
}
// Track connections per IP
const connectionsPerIp = new Map();
/**
* Check if a hostname resolves to a loopback address
* @param {string} host
* @returns {boolean}
*/
function isLoopbackHost(host) {
if (!host) return false;
const lower = host.toLowerCase();
return lower === 'localhost' || lower === '127.0.0.1' || lower === '::1'
|| lower.startsWith('127.');
}
/**
* Get first non-loopback IPv4 address of the machine.
* Used to avoid hbbr's loopback command-mode check when proxying relay connections.
* @returns {string|null}
*/
function getNonLoopbackIp() {
const interfaces = os.networkInterfaces();
for (const name of Object.keys(interfaces)) {
for (const iface of interfaces[name]) {
if (iface.family === 'IPv4' && !iface.internal) {
return iface.address;
}
}
}
return null;
}
/**
* Initialize WebSocket proxy servers and attach to HTTP server
* @param {http.Server} server - The HTTP/HTTPS server instance
* @param {Function} sessionMiddleware - Express session middleware to validate WS upgrades
*/
function initWsProxy(server, sessionMiddleware) {
// Rendezvous proxy (hbbs)
const rendezvousWss = new WebSocket.Server({ noServer: true });
// Relay proxy (hbbr)
const relayWss = new WebSocket.Server({ noServer: true });
// Handle upgrade requests — verify session cookie before allowing WebSocket.
// Paths owned: /ws/rendezvous, /ws/relay (shared upgrade router — #295).
registerUpgradeHandler(
server,
(pathname) => pathname === '/ws/rendezvous' || pathname === '/ws/relay',
(request, socket, head) => {
const url = new URL(request.url, `http://${request.headers.host}`);
const pathname = url.pathname;
// CSWSH protection: reject cross-origin upgrades before touching session
if (!enforceOrigin(request, socket, `ws-proxy ${pathname}`)) return;
// Validate the session against the real Express session store.
// Using sessionMiddleware (from server.js) populates req.session, which
// we then check for an authenticated userId. This replaces the old
// cookie-name-only check that could be bypassed with a fake cookie.
if (typeof sessionMiddleware !== 'function') {
console.warn('WS proxy: sessionMiddleware not provided — rejecting upgrade');
socket.write('HTTP/1.1 503 Service Unavailable\r\n\r\n');
socket.destroy();
return;
}
// Attach a minimal fake response so session middleware can call next()
const fakeRes = Object.create(null);
fakeRes.getHeader = () => undefined;
fakeRes.setHeader = () => {};
fakeRes.end = () => {};
fakeRes.on = () => {};
sessionMiddleware(request, fakeRes, () => {
void (async () => {
const hasUser = request.session && request.session.userId;
let hasGuest = false;
if (!hasUser) {
let guestToken = '';
let guestPeerId = '';
try {
// Prefer ?guest= on WS URL (session pages always append it for guests)
guestToken = String(
url.searchParams.get('guest') || url.searchParams.get('t') || ''
).trim();
guestPeerId = String(url.searchParams.get('peer_id') || '').trim();
if (!guestToken) {
const { GUEST_COOKIE } = require('../middleware/guestAccess');
const raw = request.headers.cookie || '';
const names = [GUEST_COOKIE, 'bd.guest', 'betterdesk.guest'];
for (const cookieName of names) {
const match = raw.split(';').map((p) => p.trim()).find((p) => p.startsWith(cookieName + '='));
if (match) {
guestToken = decodeURIComponent(match.slice(cookieName.length + 1) || '').trim();
if (guestToken) break;
}
}
}
} catch {
guestToken = '';
}
if (guestToken) {
const guestSessionId = String(
url.searchParams.get('guest_session') || ''
).trim();
if (!guestPeerId || !/^[A-Za-z0-9_-]{3,64}$/.test(guestPeerId)
|| !guestSessionId || guestSessionId.length > 128) {
console.warn(`WS proxy: rejected guest upgrade without valid peer_id for ${pathname}`);
socket.write('HTTP/1.1 403 Forbidden\r\n\r\n');
socket.destroy();
return;
}
try {
// Must validate against Go store and bind the token to
// the requested peer — non-empty guest= alone is not auth.
const betterdeskApi = require('./betterdeskApi');
const result = await betterdeskApi.apiClient.get('/guest/access-links/validate', {
params: { token: guestToken, peer_id: guestPeerId },
timeout: 5000,
});
const data = result.data || {};
if (data.valid) {
hasGuest = true;
request.guestToken = guestToken;
request.guestGrant = data;
request.guestPeerId = guestPeerId;
request.guestSessionId = guestSessionId;
}
} catch (err) {
console.warn(
`WS proxy: guest token validation failed for ${pathname}: ${err.message || err}`
);
}
}
}
if (!hasUser && !hasGuest) {
console.warn(`WS proxy: Rejected upgrade to ${pathname} — no authenticated session (ip: ${request.socket?.remoteAddress})`);
socket.write('HTTP/1.1 401 Unauthorized\r\n\r\n');
socket.destroy();
return;
}
if (pathname === '/ws/rendezvous') {
const panelRole = request.session?.user?.role;
if (hasUser && !roleHasPermission(panelRole, 'device.connect')) {
console.warn(`WS proxy: Rejected rendezvous upgrade for non-operator role ${panelRole || 'unknown'}`);
socket.write('HTTP/1.1 403 Forbidden\r\n\r\n');
socket.destroy();
return;
}
rendezvousWss.handleUpgrade(request, socket, head, (ws) => {
rendezvousWss.emit('connection', ws, request);
});
} else {
relayWss.handleUpgrade(request, socket, head, (ws) => {
ws._betterdeskMessageTransport =
url.searchParams.get('transport') === 'message';
relayWss.emit('connection', ws, request);
});
}
})();
});
}
);
// Parse target host/port from config
const hbbsHost = config.wsProxy?.hbbsHost || 'localhost';
const hbbsPort = config.wsProxy?.hbbsPort || 21116;
let hbbrHost = config.wsProxy?.hbbrHost || 'localhost';
const hbbrPort = config.wsProxy?.hbbrPort || 21117;
// CRITICAL: hbbr treats loopback TCP connections as admin command interface
// and will NOT process relay requests from 127.0.0.0/8.
// If hbbrHost is loopback, replace with the machine's non-loopback IP.
if (isLoopbackHost(hbbrHost)) {
const nonLoopback = getNonLoopbackIp();
if (nonLoopback) {
console.log(` WebSocket proxy: hbbr host changed from '${hbbrHost}' to '${nonLoopback}' (avoiding loopback command mode)`);
hbbrHost = nonLoopback;
} else {
console.warn(' WebSocket proxy: WARNING - could not find non-loopback IP for hbbr, relay connections may fail!');
}
}
// Rendezvous connections
rendezvousWss.on('connection', (ws, req) => {
handleProxyConnection(ws, req, hbbsHost, hbbsPort, 'rendezvous', {
guestGrant: req.guestGrant,
guestToken: req.guestToken,
guestPeerId: req.guestPeerId,
guestSessionId: req.guestSessionId,
});
});
// Relay connections
relayWss.on('connection', (ws, req) => {
handleProxyConnection(ws, req, hbbrHost, hbbrPort, 'relay', {
messageTransport: ws._betterdeskMessageTransport === true,
guestGrant: req.guestGrant,
guestToken: req.guestToken,
guestPeerId: req.guestPeerId,
guestSessionId: req.guestSessionId,
});
});
console.log(` WebSocket proxy: /ws/rendezvous -> ${hbbsHost}:${hbbsPort}`);
console.log(` WebSocket proxy: /ws/relay -> ${hbbrHost}:${hbbrPort}`);
return { rendezvousWss, relayWss };
}
/**
* Handle a single proxied WebSocket connection
*/
function handleProxyConnection(ws, req, targetHost, targetPort, label, options = {}) {
const clientIp = req.headers['x-forwarded-for']?.split(',')[0]?.trim()
|| req.socket.remoteAddress
|| 'unknown';
// Rate limit connections per IP
const currentCount = connectionsPerIp.get(clientIp) || 0;
if (currentCount >= MAX_CONNECTIONS_PER_IP) {
console.warn(`WS proxy [${label}]: Connection limit reached for ${clientIp}`);
ws.close(1008, 'Too many connections');
return;
}
connectionsPerIp.set(clientIp, currentCount + 1);
// Idle timeout
let idleTimer = null;
const messageTransport = options.messageTransport === true;
const relayDecoder = messageTransport ? createRelayFrameDecoder() : null;
const guestGrant = options.guestGrant || null;
const guestToken = String(options.guestToken || '').trim();
const guestPeerId = String(options.guestPeerId || '').trim();
const guestRendezvousDecoder = guestGrant && label === 'rendezvous'
? createRelayFrameDecoder()
: null;
let guestRelayBuffer = Buffer.alloc(0);
let guestRelayValidated = false;
let guestSessionConsumed = false;
let guestOpenedAt = 0;
let guestOpenedReported = false;
let guestValidationTimer = null;
let unregisterGuestBridge = () => {};
let cleanupCause = 'unknown';
let wsCloseCode = null;
let wsCloseReason = '';
const resetIdleTimer = () => {
if (idleTimer) clearTimeout(idleTimer);
idleTimer = setTimeout(() => {
console.log(`WS proxy [${label}]: Idle timeout for ${clientIp}`);
cleanup('idle-timeout');
}, IDLE_TIMEOUT_MS);
};
function reportGuestEvent(event, reason = '') {
if (!guestGrant || !guestPeerId) return;
const betterdeskApi = require('./betterdeskApi');
const duration = guestOpenedAt
? Math.max(0, Date.now() - guestOpenedAt)
: 0;
betterdeskApi.apiClient.post('/guest/access-links/events', {
event,
grant_id: guestGrant.id || '',
peer_id: guestPeerId,
session_id: options.guestSessionId || '',
transport: label,
source_ip: clientIp,
duration_ms: duration,
reason,
}).catch((err) => {
console.warn(`WS proxy [${label}]: guest audit event failed: ${err.message || err}`);
});
}
// Connect to target TCP server
const tcp = net.createConnection({ host: targetHost, port: targetPort }, () => {
resetIdleTimer();
});
tcp.on('error', (err) => {
console.error(`WS proxy [${label}]: TCP error (${targetHost}:${targetPort}):`, err.message);
cleanup('tcp-error', { error: err.message });
});
tcp.on('close', (hadError) => {
cleanup('tcp-close', { hadError: !!hadError });
});
// TCP -> WebSocket
tcp.on('data', (data) => {
resetIdleTimer();
if (ws.readyState === WebSocket.OPEN) {
if (!messageTransport) {
ws.send(data);
return;
}
try {
for (const payload of relayDecoder.feed(data)) {
ws.send(payload, { binary: true });
}
} catch (err) {
console.error(`WS proxy [${label}]: invalid relay TCP frame:`, err.message);
cleanup('invalid-tcp-frame', { error: err.message });
}
}
});
// WebSocket -> TCP
ws.on('message', (data) => {
void (async () => {
resetIdleTimer();
if (!tcp.destroyed) {
// Ensure we send Buffer, not string
const buf = Buffer.isBuffer(data) ? data : Buffer.from(data);
try {
let isGuestSessionOpening = false;
if (guestGrant) {
if (label === 'rendezvous') {
for (const payload of guestRendezvousDecoder.feed(buf)) {
const message = decodeRendezvousPayload(payload);
if (!message || !guestTargetMatches(message, guestPeerId)) {
console.warn(
`WS proxy [${label}]: guest target mismatch for grant ${guestGrant.id || 'unknown'}`
);
cleanup('guest-target-mismatch');
return;
}
if (message.punchHoleRequest || message.requestRelay) {
isGuestSessionOpening = true;
}
}
} else if (!guestRelayValidated) {
if (guestRelayBuffer.length + buf.length > 1024 * 1024) {
cleanup('guest-invalid-relay-frame');
return;
}
guestRelayBuffer = Buffer.concat([guestRelayBuffer, buf]);
const message = decodeRendezvousPayload(guestRelayBuffer);
if (!message) return;
const request = message.requestRelay;
if (!request || String(request.id || '') !== guestPeerId) {
console.warn(
`WS proxy [${label}]: guest relay target mismatch for grant ${guestGrant.id || 'unknown'}`
);
cleanup('guest-target-mismatch');
return;
}
guestRelayValidated = true;
isGuestSessionOpening = true;
}
}
if (guestGrant && isGuestSessionOpening && !guestSessionConsumed) {
try {
await consumeGuestSession(
guestGrant,
guestToken,
guestPeerId,
options.guestSessionId
);
if (cleaned) return;
guestSessionConsumed = true;
guestOpenedAt = Date.now();
if (!guestOpenedReported) {
guestOpenedReported = true;
reportGuestEvent('opened');
}
} catch (err) {
console.warn(
`WS proxy [${label}]: guest session rejected: ${err.message || err}`
);
cleanup('guest-use-rejected');
return;
}
}
tcp.write(messageTransport ? encodeRelayFrame(buf) : buf);
} catch (err) {
console.error(`WS proxy [${label}]: invalid relay WS frame:`, err.message);
cleanup('invalid-ws-frame', { error: err.message });
}
}
})();
});
ws.on('close', (code, reason) => {
wsCloseCode = Number.isFinite(code) ? code : null;
wsCloseReason = reason ? Buffer.from(reason).toString('utf8') : '';
cleanup('ws-close');
});
ws.on('error', (err) => {
console.error(`WS proxy [${label}]: WebSocket error:`, err.message);
cleanup('ws-error', { error: err.message });
});
let cleaned = false;
function cleanup(cause = 'unknown', details = {}) {
if (cleaned) return;
cleaned = true;
cleanupCause = cause;
if (idleTimer) clearTimeout(idleTimer);
if (guestValidationTimer) clearTimeout(guestValidationTimer);
unregisterGuestBridge();
if (guestOpenedReported) reportGuestEvent('closed', cause);
if (!tcp.destroyed) {
tcp.destroy();
}
if (ws.readyState === WebSocket.OPEN || ws.readyState === WebSocket.CONNECTING) {
ws.close();
}
// Decrement connection counter
const count = connectionsPerIp.get(clientIp) || 1;
if (count <= 1) {
connectionsPerIp.delete(clientIp);
} else {
connectionsPerIp.set(clientIp, count - 1);
}
const closeSuffix = wsCloseCode == null
? ''
: ` code=${wsCloseCode}${wsCloseReason ? ` reason=${JSON.stringify(wsCloseReason)}` : ''}`;
const detailSuffix = details.error
? ` error=${JSON.stringify(String(details.error))}`
: '';
console.log(`WS proxy [${label}]: closed for ${clientIp} cause=${cleanupCause}${closeSuffix}${detailSuffix}`);
}
if (guestGrant && guestToken && guestPeerId) {
unregisterGuestBridge = registerGuestBridge(guestGrant.id, cleanup);
const revalidateGuestGrant = async () => {
if (cleaned) return;
try {
const betterdeskApi = require('./betterdeskApi');
const result = await betterdeskApi.apiClient.get('/guest/access-links/validate', {
params: { token: guestToken, peer_id: guestPeerId },
timeout: 5000,
});
if (!result.data?.valid) {
cleanup('guest-grant-invalid');
return;
}
} catch (err) {
console.warn(
`WS proxy [${label}]: guest grant revalidation failed: ${err.message || err}`
);
// A failed dependency check is not proof of revocation. Retry
// until the grant's own expiry, then close deterministically.
}
if (cleaned) return;
const expiresAt = new Date(guestGrant.expires_at).getTime();
const remaining = Number.isFinite(expiresAt) ? expiresAt - Date.now() : 0;
if (remaining <= 0) {
cleanup('guest-grant-expired');
return;
}
guestValidationTimer = setTimeout(
revalidateGuestGrant,
Math.min(GUEST_REVALIDATION_INTERVAL_MS, remaining)
);
};
revalidateGuestGrant();
}
}
module.exports = {
initWsProxy,
invalidateGuestGrant,
_guestProtocol: { decodeRendezvousPayload, guestTargetMatches },
_relayFraming: { encodeRelayFrame, createRelayFrameDecoder, MAX_RELAY_FRAME_SIZE },
};