feat: 支持自托管的 remote-control-server (#214)

* feat: 支持自托管的 remote-control-server (#214)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

packages/remote-control-server/src/auth/jwt.ts

@@ -0,0 +1,92 @@
+import { createHmac, timingSafeEqual } from "node:crypto";
+
+/**
+ * Lightweight JWT implementation using HMAC-SHA256.
+ * No external dependencies — uses Node.js crypto.
+ *
+ * Token format: base64url(header).base64url(payload).base64url(signature)
+ * Used for V2 worker authentication (session ingress / SSE / CCR).
+ */
+
+interface JwtPayload {
+  session_id: string;
+  role: string;
+  iat: number;
+  exp: number;
+}
+
+function base64url(data: string | Buffer): string {
+  return Buffer.from(data as unknown as ArrayLike<number>)
+    .toString("base64")
+    .replace(/\+/g, "-")
+    .replace(/\//g, "_")
+    .replace(/=+$/, "");
+}
+
+function base64urlDecode(str: string): string {
+  const padded = str.replace(/-/g, "+").replace(/_/g, "/");
+  return Buffer.from(padded, "base64").toString("utf-8");
+}
+
+function getSigningKey(): string {
+  const key = process.env.RCS_API_KEYS?.split(",").filter(Boolean)[0];
+  if (!key) throw new Error("No API key configured for JWT signing");
+  return key;
+}
+
+/** Generate a JWT for worker authentication. */
+export function generateWorkerJwt(
+  sessionId: string,
+  expiresInSeconds: number,
+): string {
+  const header = { alg: "HS256", typ: "JWT" };
+  const payload: JwtPayload = {
+    session_id: sessionId,
+    role: "worker",
+    iat: Math.floor(Date.now() / 1000),
+    exp: Math.floor(Date.now() / 1000) + expiresInSeconds,
+  };
+
+  const headerB64 = base64url(JSON.stringify(header));
+  const payloadB64 = base64url(JSON.stringify(payload));
+  const signingInput = `${headerB64}.${payloadB64}`;
+
+  const signature = createHmac("sha256", getSigningKey())
+    .update(signingInput)
+    .digest();
+
+  return `${signingInput}.${base64url(signature)}`;
+}
+
+/**
+ * Verify a JWT and return its payload, or null if invalid/expired.
+ * Uses timing-safe comparison to prevent timing attacks.
+ */
+export function verifyWorkerJwt(token: string): JwtPayload | null {
+  const parts = token.split(".");
+  if (parts.length !== 3) return null;
+
+  const [headerB64, payloadB64, signatureB64] = parts;
+
+  // Verify signature
+  const signingInput = `${headerB64}.${payloadB64}`;
+  const expectedSig = createHmac("sha256", getSigningKey())
+    .update(signingInput)
+    .digest();
+  const actualSig = Buffer.from(
+    signatureB64.replace(/-/g, "+").replace(/_/g, "/"),
+    "base64",
+  );
+
+  if (expectedSig.length !== actualSig.length) return null;
+  if (!timingSafeEqual(expectedSig, actualSig)) return null;
+
+  // Decode payload
+  try {
+    const payload: JwtPayload = JSON.parse(base64urlDecode(payloadB64));
+    if (payload.exp < Math.floor(Date.now() / 1000)) return null;
+    return payload;
+  } catch {
+    return null;
+  }
+}