api: move hmac secrets to single file

api/src/cobalt.js

@@ -20,7 +20,7 @@ app.disable("x-powered-by");
 if (env.apiURL) {
     const { runAPI } = await import("./core/api.js");
 
-    if (cluster.isPrimary && isCluster) {
+    if (isCluster) {
         initCluster();
     }
 

api/src/core/api.js

@@ -11,7 +11,7 @@ import match from "../processing/match.js";
 import { env, setTunnelPort } from "../config.js";
 import { extract } from "../processing/url.js";
 import { Green, Bright, Cyan } from "../misc/console-text.js";
-import { generateHmac, generateSalt } from "../misc/crypto.js";
+import { hashHmac } from "../security/secrets.js";
 import { randomizeCiphers } from "../misc/randomize-ciphers.js";
 import { verifyTurnstileToken } from "../security/turnstile.js";
 import { friendlyServiceName } from "../processing/service-alias.js";
@@ -30,7 +30,6 @@ const version = await getVersion();
 
 const acceptRegex = /^application\/json(; charset=utf-8)?$/;
 
-const ipSalt = generateSalt();
 const corsConfig = env.corsWildcard ? {} : {
     origin: env.corsURL,
     optionsSuccessStatus: 200
@@ -74,7 +73,7 @@ export const runAPI = (express, app, __dirname, isPrimary = true) => {
         max: 10,
         standardHeaders: true,
         legacyHeaders: false,
-        keyGenerator: req => generateHmac(getIP(req), ipSalt),
+        keyGenerator: req => hashHmac(getIP(req), 'rate'),
         handler: handleRateExceeded
     });
 
@@ -83,7 +82,7 @@ export const runAPI = (express, app, __dirname, isPrimary = true) => {
         max: (req) => req.rateLimitMax || env.rateLimitMax,
         standardHeaders: true,
         legacyHeaders: false,
-        keyGenerator: req => req.rateLimitKey || generateHmac(getIP(req), ipSalt),
+        keyGenerator: req => req.rateLimitKey || hashHmac(getIP(req), 'rate'),
         handler: handleRateExceeded
     })
 
@@ -92,7 +91,7 @@ export const runAPI = (express, app, __dirname, isPrimary = true) => {
         max: (req) => req.rateLimitMax || env.rateLimitMax,
         standardHeaders: true,
         legacyHeaders: false,
-        keyGenerator: req => req.rateLimitKey || generateHmac(getIP(req), ipSalt),
+        keyGenerator: req => req.rateLimitKey || hashHmac(getIP(req), 'rate'),
         handler: (req, res) => {
             return res.sendStatus(429)
         }
@@ -172,7 +171,7 @@ export const runAPI = (express, app, __dirname, isPrimary = true) => {
                 return fail(res, "error.api.auth.jwt.invalid");
             }
 
-            req.rateLimitKey = generateHmac(token, ipSalt);
+            req.rateLimitKey = hashHmac(token, 'rate');
         } catch {
             return fail(res, "error.api.generic");
         }

api/src/misc/cluster.js

@@ -1,6 +1,7 @@
-import net from "node:net";
 import cluster from "node:cluster";
-import { isCluster } from "../config.js";
+import net from "node:net";
+import { syncSecrets } from "../security/secrets.js";
+import { env } from "../config.js";
 
 export const supportsReusePort = async () => {
     try {
@@ -17,13 +18,11 @@ export const supportsReusePort = async () => {
 }
 
 export const initCluster = async () => {
-    const { getSalt } = await import("../stream/manage.js");
-    const salt = getSalt();
-
+    if (cluster.isPrimary) {
         for (let i = 1; i < env.instanceCount; ++i) {
-        const worker = cluster.fork();
-        worker.once('message', () => {
-            worker.send({ salt });
-        });
+            cluster.fork();
         }
+    }
+
+    await syncSecrets();
 }

api/src/misc/crypto.js

@@ -1,15 +1,7 @@
-import { createHmac, createCipheriv, createDecipheriv, randomBytes } from "crypto";
+import { createCipheriv, createDecipheriv } from "crypto";
 
 const algorithm = "aes256";
 
-export function generateSalt() {
-    return randomBytes(64);
-}
-
-export function generateHmac(str, salt) {
-    return createHmac("sha256", salt).update(str).digest("base64url");
-}
-
 export function encryptStream(plaintext, iv, secret) {
     const buff = Buffer.from(JSON.stringify(plaintext));
     const key = Buffer.from(secret, "base64url");

api/src/security/secrets.js

@@ -0,0 +1,58 @@
+import cluster from "node:cluster";
+import { createHmac, randomBytes } from "node:crypto";
+
+const generateSalt = () => {
+    if (cluster.isPrimary)
+        return randomBytes(64);
+
+    return null;
+}
+
+let rateSalt = generateSalt();
+let streamSalt = generateSalt();
+
+export const syncSecrets = () => {
+    return new Promise((resolve, reject) => {
+        if (cluster.isPrimary) {
+            let remaining = Object.values(cluster.workers).length;
+
+            for (const worker of Object.values(cluster.workers)) {
+                worker.once('message', (m) => {
+                    if (m.ready)
+                        worker.send({ rateSalt, streamSalt });
+
+                    if (!--remaining)
+                        resolve();
+                });
+            }
+        } else if (cluster.isWorker) {
+            if (rateSalt || streamSalt)
+                return reject();
+
+            process.send({ ready: true });
+            process.once('message', (message) => {
+                if (rateSalt || streamSalt)
+                    return reject();
+
+                if (message.rateSalt && message.streamSalt) {
+                    streamSalt = Buffer.from(message.streamSalt);
+                    rateSalt = Buffer.from(message.rateSalt);
+                    resolve();
+                }
+            });
+        } else reject();
+    });
+}
+
+
+export const hashHmac = (value, type) => {
+    let salt;
+    if (type === 'rate')
+        salt = rateSalt;
+    else if (type === 'stream')
+        salt = streamSalt;
+    else
+        throw "unknown salt";
+
+    return createHmac("sha256", salt).update(value).digest();
+}

api/src/stream/manage.js

@@ -4,11 +4,11 @@ import { nanoid } from "nanoid";
 import { randomBytes } from "crypto";
 import { strict as assert } from "assert";
 import { setMaxListeners } from "node:events";
-import cluster from "node:cluster";
 
-import { env, tunnelPort, isCluster } from "../config.js";
+import { env, tunnelPort } from "../config.js";
 import { closeRequest } from "./shared.js";
-import { decryptStream, encryptStream, generateHmac, generateSalt } from "../misc/crypto.js";
+import { decryptStream, encryptStream } from "../misc/crypto.js";
+import { hashHmac } from "../security/secrets.js";
 
 // optional dependency
 const freebind = env.freebindCIDR && await import('freebind').catch(() => {});
@@ -16,33 +16,13 @@ const freebind = env.freebindCIDR && await import('freebind').catch(() => {});
 const streamCache = new Store('streams');
 
 const internalStreamCache = new Map();
-let hmacSalt = cluster.isPrimary ? generateSalt() : null;
-let _saltRead = false;
-
-export const getSalt = () => {
-    if (!isCluster) throw "salt can only be read on multi-process instances";
-    if (!cluster.isPrimary) throw "only primary cluster can read salt";
-    if (_saltRead) throw "salt was already read";
-
-    _saltRead = true;
-    return hmacSalt;
-}
-
-if (cluster.isWorker) {
-    process.send({ ready: true });
-    process.once('message', (message) => {
-        if (message.salt && !hmacSalt) {
-            hmacSalt = message.salt;
-        }
-    });
-}
 
 export function createStream(obj) {
     const streamID = nanoid(),
         iv = randomBytes(16).toString('base64url'),
         secret = randomBytes(32).toString('base64url'),
         exp = new Date().getTime() + env.streamLifespan * 1000,
-        hmac = generateHmac(`${streamID},${exp},${iv},${secret}`, hmacSalt),
+        hmac = hashHmac(`${streamID},${exp},${iv},${secret}`, 'stream').toString('base64url'),
         streamData = {
             exp: exp,
             type: obj.type,
@@ -167,7 +147,7 @@ function wrapStream(streamInfo) {
 
 export async function verifyStream(id, hmac, exp, secret, iv) {
     try {
-        const ghmac = generateHmac(`${id},${exp},${iv},${secret}`, hmacSalt);
+        const ghmac = hashHmac(`${id},${exp},${iv},${secret}`, 'stream').toString('base64url');
         const cache = await streamCache.get(id.toString());
 
         if (ghmac !== String(hmac)) return { status: 401 };