What I want
I have a list of people with all their personal information (name, first name, date of birth, email, etc.). I created an account for each of these people using their email/phone + a password I generated for them.
I want to send to each of these people an email/SMS with a link allowing them, once clicked :
to be directly connected on our website, without having to type a password or using a third party as Google/Facebook/etc.
and I want the link not to expire after the first use. The user must be able to click on it several times and be connected to our website each time.
What I tried
This is what I tried so far, unsuccessfully :
Passwordless Auth with email link: using both backend and frontend. Doesn't fit my needs because the signin link works only once by design.
Create a custom token with Firebase: as I understood, the token will expire 3600 seconds after creation, which is not useful for me.
Implement anonymous auth: it still need the user to type email+password at some point if you want to convert the anonymous account to a permanent account (because I don't want to use Google/Facebook/etc auth). Plus, it will need consequent changes in all my website code to work.
At this point I realized that Firebase doesn't have a solution that fits my needs. I started to fiddled around as best I could.
The idea
It works as the following:
First I create an account for the user in Firebase + a unique document in a collection in Firestore. That document contains 3 fields: magic_token, email, password.
Then, I create a link to our website with a unique token as a parameter in it. I store the token as magic_token in the document I described above. I send the link to the user.
The user clicks on the link, get redirected to my website. In the front, I detect the presence of the token in the parameters of the URL, I retrieve the document in Firestore with the corresponding token.
Using the email and password stored in this document I call: signInWithEmailAndPassword() to login the user.
PROS:
it fits my needs.
it is easy to implement
CONS:
the user password is visible in Firestore.
it's not very secure.
The question
Is there a proper way to implement a Magic Link that fit my needs? If not, how can I improve my own custom token authentication ?
Related
TLDR; Can multiple different users be authenticated and retain authentication via a generated custom token IF that custom token for each of those users is being generated always by the same UID? That is, User1 gets custom token generated by UID1 (via createCustomToken(UID1)) and then signed-in with signInWithCustomToken(), THEN User2 gets and signs-in with custom token generated using UID1, then User3 same thing etc etc, can ALL these users happily remained logged-in and experience no interruptions despite these other users being authenticated in this identical manner?
Long Version:
Ok, so I am trying to create a link-sharing system wherein a user who navs to this link can access a specific subset of my project's Firebase resources.
I have already tried using Firebase's signInAnonymously() to do this, but I dont like the way that Firebase does this for a whole host of reasons I dont want to get into.
The way i want to accomplish this is by:
generating a unique link (really a Firestore unique doc ID with some access data stored in that doc)
having the unauthenticated user navigate to some landing page, calling the cloud function and passing that unique link (lets call it a UID now)
cloud function, upon recieving this UID, will createCustomToken(UID), returning the token back to calling user
and the user will authenticate themselves with signInWithCustomToken(returnedToken) and access provisioned resources
Now, that is all well and good, but my question is:
If two (or any amount more people) people navigate to that same link and therefore pass and create token with the same UID, will they all be ok to continue happily using Firebase resources? Or is it because they got tokens created for them which utilised the same UID a sort of token-conflict is made, and therefore any next user who authenticates in this manner will revoke the previous user's auth token.
I havent been able to try this, and it seems like every question asked about these custom tokens relates to the generation and expiry time of them, which I understand. I wish the Auth docs were more clear on the mechnics and pitfalls of using Custom Tokens. I also havent been able to try it myself as it would be quite alot of refactoring, and was hoping someone could give me a straight answer to this.
Yes, a user can login on multiple devices without affecting other sessions at the same time irrespective of which auth method you use.
I'm not sure what the unique links are but it's not a good idea to pass the UID itself around if you function just takes a UID and returns a custom token as UIDs are pretty short and just a random string. It might be best to add a custom signed JWT in the links that contain the UID in payload so you can verify them before creating Firebase Custom Tokens.
I have a list of people with all their personal information (name, first name, date of birth, email, etc.). I created an account for each of these people in my database. I'm using Firebase.
Since I already have all my user's info, I don't want them to type it again when signing up to my website.
So I created a system using a custom token for authentication. I send them as a parameter of an URL to every one of my users.
When the user clicks on the link for the first time: he gets redirected to the signup page with all the fields pre-filled (name, date of birth, email, etc) except for the password. He types the password he wants and gets signed up.
When the user clicks on the link every other time: he gets redirected to the login page. A simple email + password interface with the email field already pre-filled. He types his password and gets logged in.
This is working great BUT I'm wondering: is this bad practice to do so?
Is this insecure to let anyone who gets the email create an account in the name of my user? Should I assume that someone, other than my user, may have total access to my user email account? Should I be prepared for this eventuality?
Since I already have all my user's info, I don't want them to type it again when signing up to my website.
If you already have the user's information, and you are allowed to process it, then it's a good practice to not let the user do something that it's already done.
is this bad practice to do so?
Not at all. That seems to me like a practice that is present almost everywhere. If you want to edit the profile data, you always have the existing data already pre-filled. The user has just to verify it or change it if needed.
Is this insecure to let anyone who gets the email create an account in the name of my user?
That sounds not like the best option if someone else can use that URL and create an account on behalf of the user. Most likely you should consider letting the user create the account only if it can validate the data through an SMS, or any other service that is specific to that user in particular.
Should I assume that someone, other than my user, may have total access to my user email account? Should I be prepared for this eventuality?
Yes indeed. You should always prepare for that. Never trust the users. There's not a perfect world out there.
I am trying to determine if the following scenario is possible with flutter and firebase:
we have users within the company who will be given access to the app, where on the homepage will be a signup another user button where they enter in that user's email and password, they get signed up, and then the original user specifies custom fields for the 2nd user, such as company name, role, position, etc.
Is this possible with flutter and firebase?
Have asked the flutter google group and was told about custom authentications, but from what I see that is just an external authentication system and doesn't show me how to let one user create another users profile with fields.
Any ideas?
The first thing to consider is whether those properties need to be in the user profile at all. The user profile is sent with every request, and should only contain information that is relevant for securing access. If you have additional information to store about the user, you should store it elsewhere (such as in one of Firebase's databases) using the UID of each user as its key.
Assuming that the information is about security (such as the role seems to be, there is no secure way to let one user set security properties (typically referred to as claims) from client-side code. As soon as this is allowed from client-side code, anyone could set such properties for anyone else. That's why setting custom claims for a user is only possible with Firebase's Admin SDKs, which are designed to run in a trusted environment - such as your development machine, a server you control, or Cloud Functions.
There are a few other options, but it's important to realize they're all implemented on top of the above approach.
There is an experimental extension that allows you to set auth claims by writing a document into Firestore, which something like this (JavaScript syntax, but the Flutter code will be similar):
db.collection("user_claims")
.doc("abc123")
.set({
role: "admin",
groups: ["example1", "example2"],
});
Now of course you'll want to make sure that you secure writing to the user_claims collection, as otherwise you'll end up with the same security risk I mentioned in the first paragraph, where everyone can claim any role they want.
Alternatively you can write your own server-side API (for example on Cloud Functions) that you expose to your application, and that then calls the Admin SDK. Here too, it is important to secure access to this API, to ensure only authorized users can call it.
I'm currently building a POS/Store admin app, when a user gets into my app, the Owner of the store will then be asked to login only once for setup purpose (e.g. a new machine), the app will then display a list of staffsName that has already been added by this owner, and then everytime a staff wants to start a new transaction, he/she will only need to click on his/her name, then enter his/her 4-digit pincode to 'login' and process the transaction.
How do i go about achieving this?
I was thinking of using firebase auth for the 'login' of the staff, but then when i log in using the staff credential, I will lose access to the uid of the owner, which is needed to access the owner's store data such as his/her products.
i'm also thinking of using firestore to store the 4digit pincode, but then i'm also concerned about security
There are multiple ways you can approach this, one where you utilize the email login by simply appending a fake domain to the username to create a valid email domain. This user account could be the designated 'user' in question, or utilize credentials inside custom claims or hidden in a database that allows the client or server (depending on your preference) to then log in as the user.
Moreover if you want the manager to login once you can add Authentication State Persistence to specify whether a signed in user should be indefinitely persisted until explicit sing out, page reload etc.
Another approach requires the user also to have a valid auth that is not an email password and you link your pin auth to that main account with Firebase Auth Linking per the documentation: https://firebase.google.com/docs/auth/web/account-linking.
This does however require that the user be registered from an auth provider such as Google, Twitter, Apple, etc. then the user will have to activate this link by logging in for authentication purposes. This can in theory be automatically generated and processed without the user knowing.
It is a long way around it since this is essentially a custom solution but it does create the flow you are looking for without having to use a custom auth provider.
I'm trying to password protect a page that contains confidential information.
Upon clicking a link, user will be shown a pop-up dialog to enter password.
If successful, redirect user to page. Otherwise, display "Wrong password".
The thing is, this can be easily overcome if user just copies the URL and add "/exec#ConfidentialPage" to the end of the URL.
Any suggestions?
If at all possible I would highly discourage implementing your own authentication system and instead rely on Google login to secure your data. See https://developers.google.com/appmaker/security/secure-your-app. My short recommendation is to:
Create a google group which contains the users you want to access the
data.
Create a role in App Maker which contains that group
Restrict access to both your data and your view to members of that role.
This is much more secure than a password based approach as #1 It's implemented by Google (implementing your own auth correctly is hard) and #2 You have a list of everyone who has access to your data in the form of the Google group.