I am building some internal API for my apps/website with Firebase Functions. Internal API as in to let my apps/website to process something on server side, its doesn't mean to open to public use.
My Apps is built with ionic and website is built with angular.
I noticed the one of Firebase Functions Pricing calculation include "Invocations". Is that Invocations means every time when I call the API equal to 1 Invocation? If yes, then the API might be abused by end user, since they able to view the website source and found the API.
I been searching solution in google, some of them suggest to enable authentication and cors, to avoid abuse of the usage. But authentication and cors still counting the Invocations right?
My code structure:
client call API by get/post method, pass user TOKEN that get from Firebase Authentication
request reach the Firebase Functions
server will check the preflight info by using CORS, as well as validate the TOKEN.
Return error if didn't pass on the (3), else proceed to execute the function.
So I assume if end user inspect my web source code and get the API URL, they can simply spam my API right? Then my bill will burst because of the load of Invocations.
If you suspect that your project is being abused, which is always possible, contact Firebase support to work towards a resolution.
Related
I need to implement a scenario where, after a file is uploaded to Google Cloud Storage, a function is triggered and processes the file. In this case, processing basically means sanitizing the file, storing it into Firestore and making it accessible via another HTTP-triggered function (a REST API of sorts).
Both user-facing ends of this process (a file upload and HTTP function) need to be secured. The process will be used in server-to-server scenario: one side is going to be a backend written in either Node.js or .NET, the other will be my Firebase solution (Cloud Storage and HTTP-triggered function as per above). In Firebase, I am going to maintain a custom set of users that should have access to the system - my idea was to use a simple system where each user will have a client id and a client secret (basically an oAuth client credentials grant type).
Based on what I read online, an only option to implement this is to use [Firebase auth with custom tokens][1]. I found lots of examples online on how to do that, but it was always about client-to-server scenarios (e.g. a Javascript web app talking to REST API). Server-to-server scenarios were not mentioned anywhere and indeed, I am unsure how to go about implementing it - I can call auth.createCustomToken(uid) just fine in my HTTP Firestore function, but there seem to be no server-side libraries I could use to call auth.SignInWithCustomTokenAsync(customToken).
To sum it up:
How can I use Firebase auth with custom tokens in server-to-server
scenario, where I need to sign in using a previously generated
custom token from a server environment?
If it is not possible,
what's the other alternative to securely implement the
above-described architecture?
I've contacted Google Support and if anyone else is struggling with this, in server-side scenarios, recommended approach is to call signInWithCustomToken endpoint in Firebase Auth REST API.
I'm working on a web app running on firebase services. I've created an express back-end running on Firebase Cloud Functions and hosted on Firebase Hosting. I am trying to add authentication so only users with permissions can access admin pages.
I tried implementing session cookies as described here. It was successful but unfortunately was vulnerable to CSRF attacks since Cloud Functions strips all cookies without the name __session from incoming requests so the proposed csrfToken cookie solution is impossible.
I then considered using Auth's persistence in the client's local storage and sending the token in the header of a GET request. Unfortunately, I have only found tutorials on how to do this for requests within scripts e.g. for APIs, not for GET requests directly from the browser to serve a page.
It seems that there should be a simple solution. Am I missing something? Is cloud functions not meant for serving web apps like this? Is there another way to protect against CSRF without cookies? If Cloud Functions still allows the __session cookie is it meant to be used for storing the user's Auth Token and if so does it protect against CSRF anyway?
Thanks
In the firebase Cloud Function you can implement your own Auth. However Firebase provided its own Authentication method. In the Cloud Function, it is simple use the ‘functions.auth.user().onCreate() ‘ method. You can refer to Extend Firebase Authentication with Cloud Functions documentation for samples.
As for your GET question, are you asking about how to programmatically extract the parameter from the URL? It'ss similar to this; you can pull the URL and substring the part that contain the token.
I'm building a React+Redux app, and using some firebase cloud functions which I call in an action creator. I was wondering, if I should save the cloud function url as an environment variable, since this code is on the client side? I already have cors implemented to only allow requestsfrom my domain.
Thank you
In general, you should always make sure that endpoints that can be called from a client are robust enough to be secure if publicly disclosed. Browser, Android, and iOS apps can all be inspected and disassembled to discover outgoing request URLs.
"Security through obscurity" can buy you time, but is not in and of itself a real means of protecting your application. Instead, you should make sure that the endpoint requires sufficient authorization (e.g. by using the Firebase ID token as per this sample).
In other words, there's no need to hide it because at the end of the day, you can't!
I am developing an native Android application using Firebase (No other custom server, only Firebase)
And it should use other services. (like Facebook API, Twitter API, etc...)
The service providers are providing the REST Api through OAuth 2.0.
I am very newbie of the OAuth 2.0, I have no knowledge, experience.
Yesterday I tried to implement "Implicit Grant", and it works fine.
I can get access_token, and I can use the REST APIs using it.
But there is a parameter "expires_in": 604800 (7 days).
This means my customer should re-authorize after 7 days. (There is no refresh_token.)
So I am considering to change the implement from "Implicit Grant" to "Authorization Code Grant".
But I already told you, I am newbie of the OAuth 2.0. (I have no experience, this is my first time.)
If I choose "Authorization Code Grant", I should store the "code" to exchange the "access_token".
Then where should I store it?
I think I can store it in local device, but it doesn't consider security.
So I want to know can I use "Firebase Realtime database/Firestore" as a storage to store "code".
I think it is reasonable.
But I am not sure...
Since you said you are a newbie , it’s worth reading more about Oauth 2.0 especially when you want to build Oauth server , a simple google search returns
https://stormpath.com/blog/what-the-heck-is-oauthhttps://stormpath.com/blog/what-the-heck-is-oauth
Fire base database alone enough to built a sever , you need endpoints to handle incoming request for you can use Cloud Functions
So if you want to implement **Authorisation Grant ** or Implicit Flow, it needs to happen in browser ,
First you can use cloud functions to handle the incoming GET request from client (in browser)
Then you return a login page where users can login,
Then handle the auth submit request from page , authenticate it , if valid generate a code or access_token (in case of implicit flow) , store that in firebase database
Return the generated code back to client using redirect uri
Finally , if Authorisation grant flow , you need another cloud functions to handle code exchange to access token
I know that we can use a Firebase backend function to send an HTTP request to Google Apps Script and receive it using "doGet()".
However, is it possible to call a Google Apps Script function from Firebase without sending an HTTP request (since it's part of the same Google account)?
My concern is with security, where one may be able to guess/sniff the right URL/parameters and then execute the Google Apps Script function (which makes a purchase). Alternatively, there may be a proper way to secure GAS web apps.
There are quite some details missing. But I think you're asking of a Google Cloud Functions/Cloud Functions for Firebase can call into an Apps Script web app or a Apps Script REST API. The answer is that they indeed can invoke those URLs (if they're publicly accessible and fall within your quota).
But that is no more security risk than that any browser can invoke these URLs. The security should not come from knowing or being able to call the URLs. If you want to secure an API, you should implement proper security on it. For more on see Authorization for Google Services in Apps SCript