Firebase Auth with different user types - android

I am working on something where I have two apps - one for a 'Requester' user and one for a 'Responder' user, and I am currently using Firebase for Auth. The users sign in with email/password combinations and this is the root of the problem:
The problem is with user collisions - because the auth module is hooked up into a single project in the Firebase console, a responder can technically log into the requester app, and vice versa, which results in issues because well, the back end conks out - the API doesnt allow them access because the DB doesnt find their data in the tables, and the apps behave erratically (read: crash).
I understand there are similar sounding questions (Android - Firebase - Different types of Users Login) but what I would really like to ask is if there can be some way I can avoid this nasty situation. Some options that come to mind are:
do a manual check in the db and log the user out if they are not of the right type - can be done but is tedious and costs data/time.
create different projects in Firebase just for each user type - this is inefficient - while I use Firebase for auth, I use Mongo for storage so this doesnt really matter but if/when I switch to Firebase for storage, then my server code will get complicated, slow and messy from having to access a different DB each to access requester and responder data
roll my own auth - feels like a bad idea, but it helps solve the immediate problem while opening a different can of worms as I also need to implement Firebase Cloud Messaging down the line
switch to another auth provider - I'm open to suggestions here
I also anticipate a scenario where a responder could create an account and use the requester app as well, in which case the collision occurs and needs to be addressed - I could ban responders from using the same email ID to sign in as a requester but that may not hold up to real world scenarios where users could (and will) want to use one email ID for everything.
Can anyone help me with the right approach to take and/or with any hints/solutions to this problem?
----- EDIT ON 14 DEC 2017 --------
I also have two apps listed under the same project (screenshot attached), so my next question is, will there even be a clash when a requester user tries to sign in/sign up as a responder or vice versa?

Consider using custom user claims and enforcing access via the Database rules or if you are using your own endpoints, by parsing the ID token and checking its claims. The Firebase admin SDK provides tools to do that: https://firebase.google.com/docs/auth/admin/custom-claims
Firebase Auth team is also working on exposing these claims to the client too to simplify UI changes needed there.

Related

Is it possible to know if firebase auth is from android app or iphone app or web app?

I wanted to know if when there's an firebase authentification, it's possible to get the source of this authentification?
To know if it's from my iphone app, android app or web app.
Why :
My web app isn't on the web, but on local server. I want to distribute this web app with server (It's for a personnal project but it could have 10 prototypes). So everybody can get my firebase config. And I don't want that someone can create account from the web firebase api because I accept google/apple and email/password auth. I can't disable email/password for my project purpose.
I hope this is clear.
To be more clear, if the email/password auth is created, is it possible to know if it's from android app or iphone app or webapp?
Thanks
The provided APIs for Firebase Auth don't give any indication which platform was used to create the account. Firebase intends for all accounts to work across all platforms using the provided SDKs and APIs accessible for each platform.
If you want to record your own per-user data in a database, you're free to do that. Note that this is not really "secure" in that each user could effectively manipulate your database or APIs to indicate whatever they want about their platform. If you do not have this sort of security in mind, then you can simply trust your own code to write, and late read, the user's platform in a database after they sign up.
To be more clear if the email/password auth is created, is it possible to know if it's from the Android app or iPhone app, or web app?
Yes, it's possible. Let's say we want to know if a user has signed in from Android. When the user creates an account from an Android device, most likely you are storing user data as objects in the database. The simplest solution I can think of is to add another property in your User class, called "platform" and set it to "Android". If the user signs up with an iPhone, then set the property to "iOS". Same thing for the web. Knowing that the user might change the device, every time the user opens the app check that value against the OS the user is using. If the OS is changed, also change the value accordingly. This way you'll always know the OS the user is using. If you allow the users to use multiple platforms, for Android, there is a function called getProviderData():
Returns a List of UserInfo objects that represents the linked identities of the user using different authentication providers that may be linked to their account.
Similar functions can be found for the other platforms as well.

Need clarification on the proper way to Authenticate (Android app)

We have implemented a Backend Server and a DataBase, with RESTFUL API. We have an Android App that can ask the server to send certain data back.
We want to implement an authentication system on the Android App.
The team suggests that I use Spring and OAuth, but I personally have no experience with those, and am not exactly convinced about the necessity of this approach.
Other friends suggest using FireBase to authenticate the users.
Could I avoid using OAuth/FireBase and simply store in the Server's Database the user's account name and its corresponding hash-salted password, along with the salt? Every request sent from the client would contain the account's name (which could probably be a unique ID generated by the server on the very first request, and saved as a SharedPreference in the phone) and the password in clear. The transmission of the request being done via HTTPS protocol (thus using TLS/SSL), the password in clear would not be revealed.
What are the possible flaws to the suggested approach in the last paragraph? And if it is a flawed approach, considering we already are using Spring for the Server (Backend), should I go for FireBase or OAuth ?
Additional context:
Bare in mind that this is the very first largish-scale project that I have been working on (it counts as a 3-credits University course). We are 3 on the project. I'm studying Computer Science but I do not necessarily have a great grasp on all the systems we are using or plan on using.
We are creating an app which allows users to view on a map alerts published by certain databases (we are currently focusing on meteorological alerts) in real-time. We want to be able to implement a login system so that people can receive notifications despite the application being closed (we are allowing users to "subscribe" to areas on the map, to specify the regions they want to receive notifications for).
OAuth, or better OpenId Connect, is a protocol, while FireBase is just one of its' commerce implementations. It's always better to follow a standard where possible than to implement your own. To see the full list of the certified OIdcC implementations look at the OIdC site, and I see at least MITREid Connect project related to Spring. I think your custom solution will work for your custom case, but only until you think about any extensibility such as Google auth or accessing some 3-rd party API.

Firebase security risk assessment query

I have a project where one app needs to access multiple databases sharded across multiple firebase projects. Now since it's the same app, i can't use the same SHA1 across all the projects where i add the app.
I do not add any google-services.json files for any of the projects, instead i fetch the database url, the storage bucket info, the api-key and the appids for each project from my own server which keeps a track of all the sharded firebase projects.
My question is, with just this much information, can anyone just authenticate to firebase?
There's no SHA1 protection so is my db even safe even with the auth!=null rule? (since anyone can initialize FirebaseApp with this info and get a FirebaseAuth instance and sign in anonymously). In summary for this one, can anyone just make an app of their own, use the info and access/manipulate my database?
How can i secure my app if it's not secure with the current configuration
Yes, that should be enough information to create a web app that connects to your database.
But this should not be a problem if the database rules and auth providers are the right ones for your case. For example:
If you don't want anonymous Users to authenticate with your app, disable the option in the Firebase console.
If you want to give access only to a limited set of users without enabling new signups (or if you have special requirements for auth) then user a custom auth provider.
If you want to limit access to certain parts of your database (or need different user roles) adjust your database rules.
I hope that answers your question!
After a little research and a little brain storming, i came to the conclusion that Oauth domain which by default is localhost and the firebase-app domain will prevent anyone from directly authenticating to my Firebase app.
Even if the api-key and other info is exposed, as long as the service-account is hidden, the auth-domain will protect my app since the auth-domain will cause the authentication from a non-authorized domain to fail. Maybe I'll even want to remove the localhost in production :)

How do I enable secure user data access using Firebase without requiring user to login

Say I'm building some basic not-so-secure Android app, and I want to use firebase as a DB, but I really don't want the user to login. What would be my best choice of authentication?
If I allow "Annonymous" login - will this mean a big security hole, or would it just mean that programmatically I am allowed to change data anywhere in the db?
Does firebase support automatic creation/logging of user using my own custom user/id mechanism (without any user intervention)? Docs aren't very clear about that...
Anonymous log-in just provide authentication, that means you can associate a Unique ID to each of your user.
This de facto create a user ID and a Auth Token that is persisted in the phone between runs of your app. Token is refreshed when you call signInAnonymously().
Check this link for hits on how to handle anonymous logins.
Talking about security, anonymous login is not a bad practice. Obviously if you want to keep your DB safe you have to write custom access rules:
e.g. you probably want "anon_user322" to read your page content, but definitely not to modify or delete it.
Achieving this is not so hard, you have just to go to your FirebaseConsole and write your own rules for the Database.
You can find on this page a good starting guide. I suggest to watch this talk from Google I/O 2016, it is a bit long but you will be able to understand the basic of authentication and security in Firebase Database just with the first 25-30 minutes.
I was using annoymous sign in at first but it has somedown sides like you cannot export and import the exact same user on another device. Therefore i started using password authentication. You can just generate an pseudo email via uuid#yourappdomain.com and also generate the password and keep it within the appdata.
For security purpose you wont get around setting up rules for writing and reading data but it is working quite simple and easy enough to test with both methods annonymous and passoword auth.

Least invasive way to uniquely identify Android user

How can you uniquely identify a user who has installed your app so that:
You will know it is them if they delete and reinstall your app;
You will know it is them if they install your app on a second device they intend to use simultaneously?
Just as an example, I see that the Netflix app will automatically link to your desktop account without any user interaction. I'm guessing that they use accountManager.getAccounts() or similar method, because they also require the GET_ACCOUNTS permission. But of course that permission is marked as Protection level: dangerous. Is there any technique to do this that is less invasive or potentially alarming?
The key to answering this is to be both simple (for the user) and minimally invasive. Android provides heaps of ways to identify users and many of those ways involve piercing a user's privacy, and if that is the only way, I will do what I do now (optional email registration). I just want a way for my app to know if a user already is registered in my system across installs without having to interview the user (username/password, email address, third-party OAuth, etc).
My main reasons are:
I don't want support requests from users who orphaned their content after a reinstall; and
I don't want to host lots of orphaned content.
Have a look at Firebase Authentication. It's quite seamless and does not require much effort to incorporate. Also it does not feel intrusive or cumbersome to the end user.
Here is a video tutorial by Google.
EDIT:
In case your users are sure to have a cellular device with a phone number, you can use AccountKit. It is also what they call OTA (One Time Authentication). AccountKit uses just the users phone number to verify and validate users.
EDIT:
Firebase Authentication now features 'Phone Verification' which is similar to AccountKit mentioned above. Both are good services. However, Firebase phone verification lets you make your own UI from scratch (which means a lot better control than AccountKit). Also, if you don't want to make your UI, you can always use FirebaseUI
i have implemented something that seems little similar to your thing by push notification , i can get error if user uninstalled my app(and from the registration id i get the user) , and if he re installed he obtain a new registration id , and try to get the user UUID for different devices
I think the simplest way would be using UUID and storing the hash on sharedPreferences. You should generate the UUID as earlier as possible in your app.
sharedPrefs = context.getSharedPreferences(APP_SHARED_PREFS,Activity.MODE_PRIVATE);
if (sharedPrefs.getString("YOUR-KEY-TO-THE-UUID") == null || "".equals(sharedPrefs.getString("YOUR-KEY-TO-THE-UUID"))){
prefsEditor = sharedPrefs.edit();
prefsEditor.putString("YOUR-KEY-TO-THE-UUID", UUID.randomUUID().toString());
prefsEditor.commit();
}
I think that the best way would be implementing login with Google or Facebook. This is quite seamless for users, safe enough (as Google and Facebook considered trusted), you do not need to implement your email registration and you will have identity across devices.
If your app is Android only and you'd like to provide identity without any account creation for the user, I believe using Google Account name/id is the best choice (Accessing Google Account Id /username via Android) since you have to use Google Account on Android phone (unless you root it, delete Google Play Services etc).
If you'd like to only address the first point of your question (identify after reinstall) there's a Device Id -Secure.getString(getContext().getContentResolver(), Secure.ANDROID_ID);
though it's not 100% reliable (f.e Factory Reset resets this value)
The standard for achieving this sort of functionality is through the use of JSON web tokens (JWT) in conjunction with standard restful api traffic.
Assuming your android application interacts with a RESTful api for all crudlike operations and business logic, then using a JWT as an authentication identifier to your api can work quite well. You can embed information in each JWT allowing you to identify whatever you like (the user id in the database, the device id of whereve the user logged in from, etc). A JWT is essentially a datastructure allowing you to store information to be used by the API.
Some basics for how this works:
Getting the JWT into the app: A user logs in to the application using their username/password. The
api then returns an encrypted JWT to be used by the client for all future requests. Don't try to do
the encryption yourself. Any language that can handle serving an api
will have libraries for this.
Using information in the JWT: The JWT is itself a datastructure. For example, it might look like this:
{
user_id: 1,
device_id: 44215,
device_os: android,
}
Your api will decrypt the JWT when it is supplied for
authentication via the request header, and then have that information available in the
context of the session.
If you provide the language used by your api then I might be able to recommend a library.
I will conclude by referring to the final requirement you submitted which states essentially that you do not want to have to interview the user across installs. If I understand your meaning, that you want a user to be able to simply install the application and begin using it without supplying authentication credentials, then there is no way to achieve that securely. You might be able to come up with a hackish way to get it to work, but it will be fundamentally insecure.

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