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.
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 developing an android app with firebase as a backend and I heard a word named Admin SDK. I had searched for it and found it is used to manage data.
But I have a doubt that firebase provides a console webpage (console.firebase.google.com) to manage data, but why there is a separate Admin SDK?
Can someOne please explain...
The firebase admin SDK provides a simple and easy way to modify firebase settings and data using API calls.
For example, you might ask: why should you even have a regular SDK to store data? After all, you can store and save data directly from the web interface. It is, however, simply not secure or practical to have users update their own data each time using the console.
Similarly, the admin SDK is just like the regular SDK but with administrator permissions. For example, it allows you to bypass the rules set up using your firestore rules. The Firebase admin SDK is meant to be used on your backend - so you know it is running trusted software. You know that it will act the way you expect it to, unlike code running client-side that can't be trusted.
For example, let's say that you want to be able to delete a user's post if certain conditions are met. The user will make the request to your server, and it will check if the conditions are met, and then delete the post using its admin privilages. Sure you could technically automate this using firestorm rules, but those can be quite cumbersome and might not work in more complicated examples.
You can also even use it to integrate with other applications like connecting your app to a moderation tool or a curse detector that can't or shouldn't run on the client's device.
Is your question is why does Admin SDK exists?
There are several administrative tasks such as deleting users, listing collections and many more which the client cannot and should not be able to do.
Firebase Admin SDK has admin access to your Firebase project's resources.
It does not obey any security rules and can read/write any of your database, storage bucket..
That is why you must use Admin SDK in a server (or cloud function only). Although I feel Firebase Admin SDK is more useful if you use your own servers and authentication method. If you are using a custom server then:
It can be used to generate custom token so you can authenticate users using your own method (maybe legacy auth system) but still use Firebase Authentication to handle the auth tokens thereafter.
If you use your own database (and not any from Firebase), the Admin SDK can verify the ID Token sent by client and get identity of that user. Thereafter it's could be a simple if-else statement for you to decide if the user has access to the request resource or not.
I developed an app to test the google login feature using flutter and google authentication. The project is a closed project and only I have access to it. But recently I saw that there was a google sign in from an unknown Email ID. How did the user login without the build of my app? Has my account been hacked? What is going on?
Anyone with knowledge of your project's API Keys can access your Firebase Project using simple CURL Commands.
This is why it's a good idea to add restriction to those API Keys
In case you haven't, go to https://console.cloud.google.com and
Select your project
Click the menu icon at the top left (hamburger icon)
Go to API & Services and then credentials
You can view the APIs for your Google Cloud Project (linked to your Firebase Project) and then set restrictions for the API keys, refresh them or restrict access to specific platforms like Android or iOS.
You can also set restrictions on which components of Firebase the API key is allowed to access. For example, if your project doesn't require the use of Cloud Firestore, you can ensure that the API Key cannot be used to make calls to the Firestore Database
All said and done, I would still recommend that you shoot a mail to the Firebase Support team at https://firebase.google.com/support/troubleshooter/contact
To anyone still wondering about this:
If you provide a native google sign in and the registered
email adresses look like this:
karolynmccorkle.91842#gmail.com
normabrock.69306#gmail.com
guillermogeorge.53163#gmail.com
kylegomez.35423#gmail.com
opalbarrett.09499#gmail.com
they are probably test accounts used to generate Google Plays Pre-Launch reports.
You can read about it in the Play Console Help here.
If your app has a sign-in screen and you want the crawler to test the
sign-in process or the content behind it, you need to provide account
credentials.
Note that you do not need to provide credentials if your
app supports "Sign-in with Google,” which enables the crawler to log
in automatically.
Is it possible to set up Firebase to allow Auth/DB access into a common/shared database instance - where that instance is setup to be a centralized storage location for some 3rd party service?
For example, let's say there's an analytics service called StackOverflowAnalytics.com .. and so anyone who signs up for that service, can add tracking to their app with some secret user key. And then all the tracking for that Key is pushed to the same Firebase DB instance. And then the user can login via Firebase auth and the rules will restrict that they can only access the node for their Key.
I'm working on a 3rd party analytics client for Android - along the lines https://mint.splunk.com - where I would like to provide users a small Java/Android library they can add to their Android project, and this will help them track different data points while their app is running. The data is made accessible by saving it to the cloud from the device.
I am currently using Firebase, but it seems in order for the Firebase Auth & DB of a given Firebase instance to be accessible - the "specific app signing key" (package name/etc combo) needs to be set in the console for that Firebase instance.
It seems sharing across across unknown apps is not possible on Firebase. And that if I want to support something like that with Firebase (and not have to go to another cloud storage option), then I need to set up some proxy REST client .. like in Java or PHP .. that can serve as a centralized access point to that Firebase instance. Just wanted to check with other folks first in case this has been encountered and perhaps there are best practices already established around this particular case. Thanks
Firebase client libraries are generally not meant to be repackaged for use in other libraries. They're meant to be used at the app level.
A unique SHA-1 key is required on Android for Authentication to work with a particular app identified by package name. This requirement will definitely become a problem for you if you want this to work with arbitrary apps, since you would have to manually enter one for each app that wants to integrate.
As far as I know it's not possible to do what you want without creating a proxy, as you mentioned. I assume that firebase has some app validation that make unfeasible to share the Auth/DB.
Maybe a solution for you is to make a proxy too to access data:
"It looks like in order to access Firebase Analytics data, you export it to BigQuery. This is working for me and is automated."
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.