feat(firebase-auth): added a new middleware to verify session with fi…

…rebase-auth (#402) * fix(firebase-auth): updated firebase-auth-cloudflare-workers * add(firebase-auth): added a new `verifySessionCookieFirebaseAuth` middleware to verify w/ session cookie
honojs · Feb 24, 2024 · c9f110d · c9f110d
1 parent 9b455b5
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diff --git a/.changeset/add-verify-session-cookie-firebase-auth.md b/.changeset/add-verify-session-cookie-firebase-auth.md
@@ -0,0 +1,5 @@
+---
+'@hono/firebase-auth': minor
+---
+
+added a new `verifySessionCookieFirebaseAuth` middleware to verify w/ session cookie.
diff --git a/.gitignore b/.gitignore
@@ -14,4 +14,5 @@ coverage
 yarn-error.log
 
 # for debug or playing
-sandbox
+sandbox
+*.log
diff --git a/packages/firebase-auth/README.md b/packages/firebase-auth/README.md
@@ -4,7 +4,7 @@ This is a Firebase Auth middleware library for [Hono](https://github.com/honojs/
 
 Currently only Cloudflare Workers are supported officially. However, it may work in other environments as well, so please let us know in an issue if it works.
 
-## Synopsis
+## Synopsis (verify w/ authorization header)
 
 ### Module Worker Syntax (recommend)
 
@@ -100,6 +100,168 @@ You can specify a host for the Firebase Auth emulator. This config is mainly use
 
 If not specified, check the [`FIREBASE_AUTH_EMULATOR_HOST` environment variable obtained from the request](https://github.com/Code-Hex/firebase-auth-cloudflare-workers#emulatorenv).
 
+## Synopsis (verify w/ session cookie)
+
+### Module Worker Syntax (recommend)
+
+```ts
+import { Hono } from 'hono'
+import { setCookie } from 'hono/cookie';
+import { csrf } from 'hono/csrf';
+import { html } from 'hono/html';
+import {
+  VerifySessionCookieFirebaseAuthConfig,
+  VerifyFirebaseAuthEnv,
+  verifySessionCookieFirebaseAuth,
+  getFirebaseToken,
+} from '@hono/firebase-auth'
+import { AdminAuthApiClient, ServiceAccountCredential } from 'firebase-auth-cloudflare-workers';
+
+const config: VerifySessionCookieFirebaseAuthConfig = {
+  // specify your firebase project ID.
+  projectId: 'your-project-id',
+  redirects: {
+    signIn: "/login"
+  }
+}
+
+// You can specify here the extended VerifyFirebaseAuthEnv type.
+//
+// If you do not specify `keyStore` in the configuration, you need to set
+// the variables `PUBLIC_JWK_CACHE_KEY` and `PUBLIC_JWK_CACHE_KV` in your
+// wrangler.toml. This is because `WorkersKVStoreSingle` is used by default.
+//
+// For more details, please refer to: https://github.com/Code-Hex/firebase-auth-cloudflare-workers
+type MyEnv = VerifyFirebaseAuthEnv & {
+  // See: https://github.com/Code-Hex/firebase-auth-cloudflare-workers?tab=readme-ov-file#adminauthapiclientgetorinitializeprojectid-string-credential-credential-retryconfig-retryconfig-adminauthapiclient
+  SERVICE_ACCOUNT_JSON: string
+}
+
+const app = new Hono<{ Bindings: MyEnv }>()
+
+// set middleware
+app.get('/login', csrf(), async c => {
+  // You can copy code from here
+  // https://github.com/Code-Hex/firebase-auth-cloudflare-workers/blob/0ce610fff257b0b60e2f8e38d89c8e012497d537/example/index.ts#L63C25-L63C37
+  const content = await html`...`
+  return c.html(content)
+})
+
+app.post('/login_session', csrf(), (c) => {
+  const json = await c.req.json();
+  const idToken = json.idToken;
+  if (!idToken || typeof idToken !== 'string') {
+    return c.json({ message: 'invalid idToken' }, 400);
+  }
+  // Set session expiration to 5 days.
+  const expiresIn = 60 * 60 * 24 * 5 * 1000;
+
+  // Create the session cookie. This will also verify the ID token in the process.
+  // The session cookie will have the same claims as the ID token.
+  // To only allow session cookie setting on recent sign-in, auth_time in ID token
+  // can be checked to ensure user was recently signed in before creating a session cookie.
+  const auth = AdminAuthApiClient.getOrInitialize(
+    c.env.PROJECT_ID,
+    new ServiceAccountCredential(c.env.SERVICE_ACCOUNT_JSON)
+  );
+  const sessionCookie = await auth.createSessionCookie(
+    idToken,
+    expiresIn,
+  );
+  setCookie(c, 'session', sessionCookie, {
+    maxAge: expiresIn,
+    httpOnly: true,
+    secure: true
+  });
+  return c.json({ message: 'success' });
+})
+
+app.use('/admin/*', csrf(), verifySessionCookieFirebaseAuth(config));
+app.get('/admin/hello', (c) => {
+  const idToken = getFirebaseToken(c) // get id-token object.
+  return c.json(idToken)
+})
+
+
+export default app
+```
+
+## Config (`VerifySessionCookieFirebaseAuthConfig`)
+
+### `projectId: string` (**required**)
+
+This field indicates your firebase project ID.
+
+### `redirects: object` (**required**)
+
+This object has a property named redirects, which in turn has a property named `signIn` of type string.
+
+The `signIn` property is expected to hold a string representing the path to redirect to after a user has failed to sign-in.
+
+### `cookieName?: string` (optional)
+
+Based on this configuration, the session token has created by firebase auth is looked for in the cookie. The default is "session".
+
+### `keyStore?: KeyStorer` (optional)
+
+This is used to cache the public key used to validate the Firebase ID token (JWT). This KeyStorer type has been defined in [firebase-auth-cloudflare-workers](https://github.com/Code-Hex/firebase-auth-cloudflare-workers/tree/main#keystorer) library.
+
+If you don't specify the field, this library uses [WorkersKVStoreSingle](https://github.com/Code-Hex/firebase-auth-cloudflare-workers/tree/main#workerskvstoresinglegetorinitializecachekey-string-cfkvnamespace-kvnamespace-workerskvstoresingle) instead. You must fill in the fields defined in `VerifyFirebaseAuthEnv`.
+
+### `keyStoreInitializer?: (c: Context) => KeyStorer` (optional)
+
+Use this when initializing KeyStorer and environment variables, etc. are required.
+
+If you don't specify the field, this library uses [WorkersKVStoreSingle](https://github.com/Code-Hex/firebase-auth-cloudflare-workers/tree/main#workerskvstoresinglegetorinitializecachekey-string-cfkvnamespace-kvnamespace-workerskvstoresingle) instead. You must fill in the fields defined in `VerifyFirebaseAuthEnv`.
+
+### `firebaseEmulatorHost?: string` (optional)
+
+You can specify a host for the Firebase Auth emulator. This config is mainly used when **Service Worker Syntax** is used.
+
+If not specified, check the [`FIREBASE_AUTH_EMULATOR_HOST` environment variable obtained from the request](https://github.com/Code-Hex/firebase-auth-cloudflare-workers#emulatorenv).
+
+### What content should I read?
+
+- [Manage Session Cookies](https://firebase.google.com/docs/auth/admin/manage-cookies)
+
+### Security Considerations when using session cookies
+
+When considering that a web framework uses tokens via cookies, security measures related to traditional browsers and cookies should be considered.
+
+1. CSRF (Cross-Site Request Forgery)
+2. XSS (Cross-Site Scripting)
+3. MitM (Man-in-the-middle attack)
+
+Let's consider each:
+
+**CSRF**
+
+This is provided by hono as a standard middleware feature
+
+https://hono.dev/middleware/builtin/csrf
+
+**XSS**
+
+An attacker can inject a script and steal JWTs stored in cookies. Set the httpOnly flag on the cookie to prevent access from JavaScript. Additionally, configure "Content Security Policy" (CSP) to prevent unauthorized script execution. It is recommeded to force httpOnly and the functionality here: https://hono.dev/middleware/builtin/secure-headers
+
+**MitM**
+
+If your cookie security settings are inappropriate, there is a risk that your cookies will be stolen by a MitM. Use Samesite (or hono csrf middleware) and `__Secure-` prefix and `__Host-` prefix attributes.
+
+https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#attributes
+
+An example of good cookie settings:
+
+```ts
+const secureCookieSettings: CookieOptions = {
+  path: '/',
+  domain: <your_domain>,
+  secure: true,
+  httpOnly: true,
+  sameSite: 'Strict',
+}
+```
+
 ## Author
 
 codehex <https://github.com/Code-Hex>

diff --git a/packages/firebase-auth/package.json b/packages/firebase-auth/package.json
@@ -42,19 +42,19 @@
     "access": "public"
   },
   "dependencies": {
-    "firebase-auth-cloudflare-workers": "^1.1.0"
+    "firebase-auth-cloudflare-workers": "^2.0.2"
   },
   "peerDependencies": {
     "hono": ">=3.*"
   },
   "devDependencies": {
-    "@cloudflare/workers-types": "^4.20231025.0",
-    "firebase-tools": "^11.4.0",
-    "hono": "^3.11.7",
-    "miniflare": "^3.20231025.1",
-    "prettier": "^2.7.1",
-    "tsup": "^8.0.1",
-    "typescript": "^4.7.4",
-    "vitest": "^0.34.6"
+    "@cloudflare/workers-types": "^4.20240222.0",
+    "firebase-tools": "^13.3.1",
+    "hono": "3.12.12",
+    "miniflare": "^3.20240208.0",
+    "prettier": "^3.2.5",
+    "tsup": "^8.0.2",
+    "typescript": "^5.3.3",
+    "vitest": "^1.3.1"
   }
 }
diff --git a/packages/firebase-auth/src/index.ts b/packages/firebase-auth/src/index.ts
@@ -1,3 +1,4 @@
+import { getCookie } from 'hono/cookie'
 import type { KeyStorer, FirebaseIdToken } from 'firebase-auth-cloudflare-workers'
 import { Auth, WorkersKVStoreSingle } from 'firebase-auth-cloudflare-workers'
 import type { Context, MiddlewareHandler } from 'hono'
@@ -24,7 +25,7 @@ const defaultKeyStoreInitializer = (c: Context<{ Bindings: VerifyFirebaseAuthEnv
     const res = new Response('Not Implemented', {
       status: 501,
     })
-    throw new HTTPException(501, { res })
+    throw new HTTPException(res.status, { res })
   }
   return WorkersKVStoreSingle.getOrInitialize(
     c.env.PUBLIC_JWK_CACHE_KEY ?? defaultKVStoreJWKCacheKey,
@@ -35,29 +36,32 @@ const defaultKeyStoreInitializer = (c: Context<{ Bindings: VerifyFirebaseAuthEnv
 export const verifyFirebaseAuth = (userConfig: VerifyFirebaseAuthConfig): MiddlewareHandler => {
   const config = {
     projectId: userConfig.projectId,
-    AuthorizationHeaderKey: userConfig.authorizationHeaderKey ?? 'Authorization',
-    KeyStore: userConfig.keyStore,
+    authorizationHeaderKey: userConfig.authorizationHeaderKey ?? 'Authorization',
+    keyStore: userConfig.keyStore,
     keyStoreInitializer: userConfig.keyStoreInitializer ?? defaultKeyStoreInitializer,
     disableErrorLog: userConfig.disableErrorLog,
     firebaseEmulatorHost: userConfig.firebaseEmulatorHost,
-  }
+  } satisfies VerifyFirebaseAuthConfig
+
+  // TODO(codehex): will be supported
+  const checkRevoked = false
 
   return async (c, next) => {
-    const authorization = c.req.raw.headers.get(config.AuthorizationHeaderKey)
+    const authorization = c.req.raw.headers.get(config.authorizationHeaderKey)
     if (authorization === null) {
       const res = new Response('Bad Request', {
         status: 400,
       })
-      throw new HTTPException(400, { res })
+      throw new HTTPException(res.status, { res, message: 'authorization header is empty' })
     }
     const jwt = authorization.replace(/Bearer\s+/i, '')
     const auth = Auth.getOrInitialize(
       config.projectId,
-      config.KeyStore ?? config.keyStoreInitializer(c)
+      config.keyStore ?? config.keyStoreInitializer(c)
     )
 
     try {
-      const idToken = await auth.verifyIdToken(jwt, {
+      const idToken = await auth.verifyIdToken(jwt, checkRevoked, {
         FIREBASE_AUTH_EMULATOR_HOST:
           config.firebaseEmulatorHost ?? c.env.FIREBASE_AUTH_EMULATOR_HOST,
       })
@@ -73,7 +77,10 @@ export const verifyFirebaseAuth = (userConfig: VerifyFirebaseAuthConfig): Middle
       const res = new Response('Unauthorized', {
         status: 401,
       })
-      throw new HTTPException(401, { res })
+      throw new HTTPException(res.status, {
+        res,
+        message: `failed to verify the requested firebase token: ${String(err)}`,
+      })
     }
     await next()
   }
@@ -90,3 +97,57 @@ export const getFirebaseToken = (c: Context): FirebaseIdToken | null => {
   }
   return idToken
 }
+
+export interface VerifySessionCookieFirebaseAuthConfig {
+  projectId: string
+  cookieName?: string
+  keyStore?: KeyStorer
+  keyStoreInitializer?: (c: Context) => KeyStorer
+  firebaseEmulatorHost?: string
+  redirects: {
+    signIn: string
+  }
+}
+
+export const verifySessionCookieFirebaseAuth = (
+  userConfig: VerifySessionCookieFirebaseAuthConfig
+): MiddlewareHandler => {
+  const config = {
+    projectId: userConfig.projectId,
+    cookieName: userConfig.cookieName ?? 'session',
+    keyStore: userConfig.keyStore,
+    keyStoreInitializer: userConfig.keyStoreInitializer ?? defaultKeyStoreInitializer,
+    firebaseEmulatorHost: userConfig.firebaseEmulatorHost,
+    redirects: userConfig.redirects,
+  } satisfies VerifySessionCookieFirebaseAuthConfig
+
+  // TODO(codehex): will be supported
+  const checkRevoked = false
+
+  return async (c, next) => {
+    const auth = Auth.getOrInitialize(
+      config.projectId,
+      config.keyStore ?? config.keyStoreInitializer(c)
+    )
+    const session = getCookie(c, config.cookieName)
+    if (session === undefined) {
+      const res = c.redirect(config.redirects.signIn)
+      throw new HTTPException(res.status, { res, message: 'session is empty' })
+    }
+
+    try {
+      const idToken = await auth.verifySessionCookie(session, checkRevoked, {
+        FIREBASE_AUTH_EMULATOR_HOST:
+          config.firebaseEmulatorHost ?? c.env.FIREBASE_AUTH_EMULATOR_HOST,
+      })
+      setFirebaseToken(c, idToken)
+    } catch (err) {
+      const res = c.redirect(config.redirects.signIn)
+      throw new HTTPException(res.status, {
+        res,
+        message: `failed to verify the requested firebase token: ${String(err)}`,
+      })
+    }
+    await next()
+  }
+}