I have created an API with Firebase using Cloud Functions. GET and POST endpoints are deploeyd.
A client application is registered on the project and can access it callable functions.
I would like other client applications (using their own separate Firebase project) being able to access the API too.
However, I am concerned regarding security.
If I create HTTPS endpoints for those applications, anyone having the URL will be able to use the API ?
And if I manage to restrict access only to those authorized apps, can I allow/restrict only specific endpoints (only GET endpoints, for example)?
Related
I am using firebase admin sdk on the server to generate sign in links and send them out via custom SMTP api.
I just glanced at https://firebase.google.com/docs/auth/limits and I am well within these, but I believe there is nothing stopping a malicious third party from creating/requesting sign-in links via front end code. Is there a possibility to disable this functionality so it is only available to admin acc?
Additionally, I'd like some emails (i.e. multi factor enrolment) to not be possible, but again, given that someone can obtain some of my firebase front end details, they technically can send these?
You can restrict the API key from accessing an API (e.g. Identity Toolkit) but not disable a single method of the API for client.Sign up and delete user can be (that requires upgrading to Identity Platform) .
Firebase generates an API key when you add a web app. You can either update that or create a new key from API Credentials console.
You can then restrict what the API key in Firebase web config has access to:
However, Firebase Auth Client SDK will not work as Identity Toolkit is not selected. You'll have to proxy the requests through your backend and use a different key that can be used from your server's IP only.
Firebase Admin SDK will still be functional as usual so you can use that to perform other operations like updating/deleting users. You'll just have to write APIs on your backend for what could have been done using client SDK directly (or use Admin SDK when possible).
It might be a lot to update and I would not recommend unless you are facing rate limiting issues where Firebase Support should be able to help.
I want to use Firebase Remote Config API via REST in a mobile app. Due to technical limitations, I can't use the Android/iOS SDK so I have to resort to the REST API.
However, that API requires authentication using a private key -- obviously I can't include that key in the application.
I don't need any other Firebase service at this time, just the remote config.
How can I work around this limitation? I tried following the guide at https://firebase.google.com/docs/remote-config/use-config-rest, but as mentioned it requires to first generate a short-lived OAuth2 token using the auth API.
According to the documentation on using the Remote Config REST API:
This document describes how you can use the Remote Config REST API to read and modify the set of JSON-formatted parameters and conditions known as the Remote Config template.
So the REST API is for modifying Remote Config variables, the type of action you could also do in the Firebase console. It is not for use in regular clients, which consume the configuration variables. For that you'll have to use one of the provided clients, as there is no REST API and the wire protocol is not documented.
I am trying to integrate a google service account to a firebase project for a web application.
How can I integrate it to firebase project directly(to the backend) so that I can use APIs without API-key
By using Firebase in your project, you get access to a set of client-side APIs that you can use directly in your application without needing to include the Google Service Account. Most Firebase products rely on a separate user-authentication mechanism, and their own server-side security rules language to control what data each user has access to. So there should be no need to include the Google Service Account credentials in your application code.
If you have a specific Google API for which no Firebase SDK exists, you can call that API from something like Cloud Functions. In Cloud Functions you can securely use your service account, and then expose just the required functionality to your application code.
I have a simple web site hosted in Firebase and it is making AJAX calls to REST API endpoints in GCP Cloud Run.
I would like to limit these endpoints only to the calls coming from this site hosted in Firebase. Any call coming from any other origin should not be able to use the endpoints. What is the best way to do this?
When I was not using GCP Cloud Run, I was doing a host check on the API side to make sure that request is coming from my client but now with Cloud Run this is not possible. What else could be done?
Please note that the web-site hosted in Firebase is very simple and do not do any user authentication.
Challenge: Restrict access to a Cloud Run service to a single web application, without relying on:
Restricting access to the web application
Imposing authentication on users
This difficulty is not specific to Cloud Run. It's a general challenge for static sites backed by APIs, and a reason why many sites have authentication. As mentioned in the question comments, a server-side "host" check is not a meaningful security layer, as everything in the HTTP request can be faked. I strongly recommend you not worry about keeping your API private or add user authentication to keep the system simple and access accountable.
If that's not possible, you can still take the authentication approach by creating a single user, embedding the credentials in the site, and rotating them regularly (by redeploy to Firebase Hosting) to prevent credential theft from having indefinite access to your API. Having Firebase Auth in the middle is better than a simple API key because it prevents replay attacks from accessing your API.
I am trying to create a REST API for my app using Firebase Cloud Functions. I know how to use Admin SDK in Cloud Functions. It does have API to createUser. My front end app lets users sign in using Google and Facebook but I am not sure how to put it all together.
My app has successfully implemented Sign in with Google and Sign in with Facebook but how and what data do I transfer over to Cloud Functions (or any REST API Server for that matter) so that it could create a user in Firebase with appropriate provider.
Update for more explanation
I am creating an app for iOS and Android with some sort of cloud based backend. Right now I am experimenting with Firebase but I do not intend to tightly couple my apps to Firebase and hence do not want to pull Firebase-iOS and Firebase-Android SDKs into my app code. I want the ability and freedom to switch my backend over to AWS or Azure without changing frontend code.
The one (and only?) way is to create a server that will expose REST API endpoints and do the work on my behalf that usually SDK does. To achieve this, I am using Cloud Functions but that shouldn't matter as long as I have API to talk to actual cloud.
After putting that explanation, now my question is how do I let my users login to app using external providers like Google and Facebook and still achieve what I am trying to do. When I let users sign in with providers, I do not have their password to send to backend to create a new email/password user.
The sample code that best illustrates what you want to do here on GitHub.
It shows how to create an Express app that handles HTTP request pages. Learn more about Express to configure it for wildcards are needed.
It accepts and checks authentication tokens in HTTP requests from Firebase Authentication to validate the end user responsible for the request.