I have finally managed to implement Facebook as an external login provider on my MVC website which seems to be working fine, but I am wondering what is the correct / secure way to allow multiple external login provides to be linked to a single account.
Lets say I login with my facebook ID, no existing account is found with the same email address and my website persists a new account with their email address and their facebook token etc associated.
Next day I login with my Google account, If i check my database for an account which already has a matching email address what should I do?
1) Link this Google account with the existing account automatically and
log them in?
2) Ask the user if they wish to link their google account to the
already existing account we found?
3) Something else?
Thank You.
It is really up to you. But the default provided in the VS2013 template assumes a one to many relationship between your internal user and any external logins. If you retrieve a user with UserManager, you will see a IList for each external provider the user has logged in with.
As they log in with the new provider, you would normally not automatically know the user is associated with another provider's login. When you login it looks up a user via external ProviderKey, so initally would not find any relation to an internal user. At that point you could search users by name, email (with customized user store) and so on to link as needed.
Assuming primary emails registered on facebook and google for example, are verified by them (which they usually are) I don't see any issues on linking them together.
I think the main problem is linking internal account with email that was not verified to be from specific user. If i create an account with email of other user and that email is not verified, when the other user creates an account it associates the data of the first user together and that way both users are using the same account.
Can anyone identify and explain potential flaws for my first claim please?
Related
We create users with their email address. We send email to each user with a link to change password api with changePasswordId. When user clicks the link, he will be redirected to change password screen where he can set the password and access the application. This works.
But, now we want to allow users to register with their social Idps upon receiving invitation/verification email. Can't see any fusionauth documentation on this part.
Questions are as follows
How to let user select their social Idp while verifying their email?
Can a user have multiple logins with different Idps for one application in FusionAuth?
Is there any linking api which links all external user accounts with their fusionauth user account?
The flow we are expecting is :
Invite User -> User clicks link -> User will be presented with set
password and social logins-> User chooses google -> Google
authenticates user and returns token back to fusion auth -> fusion
auth links user's google account with already created (invited) user
account. -> Next time user logs in with google account -> Fusion auth
identifies the user and allows him to access the application.
Updated :
Let me try to explain our situation and need, with less focus on the password setup task:
We need to set up new users that are associated with google based education accounts on custom school domains. Teachers and students that might have addresses like first.last#middle.school.com We need to take the class roster from Google Classroom, initialize accounts for each student in our backend via our API which also creates FusionAuth user and app registrations for each.
Schools don't often want kids setting passwords on vendor sites. When we send the account confirmation / verification email to the new cohort of students they would ideally be directed to the approved and configured method for that domain (perhaps Google, Microsoft, other SAML or password). If we can't get selective about the confirmation method shown after the student provides her invited email address then we could present multiple confirmation options on the same screen and let the teacher direct the students to the correct choice.
But in summary we need to avoid requiring password setup and support confirmation with the invited social account when required by the school.
If I understand your use case correctly, what you want is to add the "Login with Google buttons" to the Setup Password workflow. This is different than the Email Verification workflow, so if you are looking for a way to log users in with their social profiles during Email Verification, that's something completely different. In fact, I don't think that is a use case because after the user verifies their email, they need to log in again and they can do that using their social profile.
Unfortunately, FusionAuth doesn't fully support the ability to allow someone to use the Setup Password workflow using a social login. It might be possible though using the Email Templates and Theme editor in FusionAuth. I haven't tested this, but you could try it and see if it works.
What you would do is to pass in a URL parameter to show the social login buttons during the Setup Password workflow. This would be something you could do in the email template for Setup Password like this:
Click this link to setup your password:
<a href="https://example.com/password/change/${changePasswordId}?showSocial=true">
Setup Password
</a>
Then, using the Theme editor in FusionAuth, you would add some code in to show the buttons like this (the ?? part is to handle when the parameter is missing):
[#if showSocial?? && showSocial]
show social buttons here
[/#if]
You could give that a try and see if it works for your use case. If it doesn't work, you can always open a feature request for this on our GitHub issue tracker and we can see if it receives enough upvotes to get on the roadmap. You can also engage FusionAuth professional services to build this feature for you as well.
For your other questions, you can have as many logins with external IdPs as you want for a single user. The user is unique by their email address.
I'm not sure what you mean by "linking api", but if a user logs in with an external IdP, their tokens from those external providers are stored on the user object. You can look up those values and then call third-party APIs with their access_tokens.
UPDATE 8/27/2019
Ah yes. The social login buttons do require all of the OAuth parameters, so this solution won't work because those parameters aren't part of the Setup Password workflow.
I guess I'm confused on how this actually works and whether or not this is a workflow FusionAuth should be handling. Social logins aren't generally used for account verification. They are normally used for account creation. For example, you could just send the student to FusionAuth before their account is created, they login with their Google classroom account, and then they have a FusionAuth account. Is there any reason the student can just login in after their account is created? Is that not essentially the same thing?
Could you do something where students that have accounts in Google Classroom are created in FusionAuth with a randomly generated 32 character password (for security) since they will be logging in with Google regardless. You can then just send them an email with a standard login link.
For students that login in with a username and password to FusionAuth directly, send them a Setup Password email. This will let them pick their own password.
In terms of account Linking, FusionAuth links accounts automatically based on email address (the unique login identifier actually). Therefore, you don't need to call any extra API to associate the social login with a user.
I might still not be clearly understanding the use case, so feel free to contact us directly using the form on our website. We might need to setup a web conference to discuss your needs in detail.
If I have a website where it is possible to sign in with multiple different providers (Say Facebook, GitHub, Google), what do I use as the local-to-my-site unique identifier for users? For example, if these two steps happened:
I sign in with GitHub (For the first time) and my username is mogronalol and email is mogronalol#mogronalol.com.
A local-to-my-site acccount with an email address of mogronalol#mogronalol.com and username of mogronalol is created.
If I use the email address as the local unique identifier, what happens if my email address changes in GitHub to other#other.com? The same question applies to changing username also.
If I got some sort of unique ID from GitHub, and used that as the identifier, then what do I do if my email address or username changes in GitHub. Do I just updated my local-to-my-site-copy to be the same as the one on GitHub each time I log in?
Of course, this problem is worsened if I want to log in with my Facebook account as well as my GitHub account. What happens if my email address and / or username are different across both of these? How would my local site know to link the accounts together? And if things like email address are different once the accounts are linked, which one do I use?
First, maybe you could try on some tutorial to feel how OAuth work.
After your OAuth authentication succeed, your website will receive a series of information provided by OAuth provider.example
Within this information, there are two special columns called uid and provider used to recognize user from OAuth provider.
You will use these two columns to tell which provider the authentication come from (i.e. facebook or github), also you need to save these fields to your account columns.
Then use rest of information to create the account in your website.
For example, use OAuth provider's email as email(github's email as email).
After you create account, every time you login server from OAuth provider.
You only need to check provider and uid in account column.
Let's back to your question.
If I use the email address as the local unique identifier, what happens if my email address changes in GitHub to other#other.com? The same question applies to changing username also.
If I got some sort of unique ID from GitHub, and used that as the identifier, then what do I do if my email address or username changes in GitHub. Do I just updated my local-to-my-site-copy to be the same as the one on GitHub each time I log in?
Github's email or user change won't affect your login (We only check provider and uid fields to login user).
I suggest not to sync with your OAuth provider's information(We only use OAuth provider's information when create account).
If you are going to support multiple OAuth provider, I suggest you read through this article.
You have to separate uid and provider to other table called identity.
Each account has many identities.
I also did it before.
If you don't mind, here is the sample code snippet to deal with multiple OAuth providers.
You have to think about the logic in your login flow.
For example, user has signed in and login OAuth => Link account with OAuth provider
User not signed in and login OAuth => If find user with OAuth, login, else create account using OAuth provider's information
Of course, this problem is worsened if I want to log in with my Facebook account as well as my GitHub account. What happens if my email address and / or username are different across both of these? How would my local site know to link the accounts together? And if things like email address are different once the accounts are linked, which one do I use?
We only link account, when user is already signed in.
When you link account, you could determine to use OAuth provider's information to update account(just like you used to register account).
I suggest to use the original email not to update it from OAuth provider's information.
I've been looking into OAuth for a while, but haven't implemented it in any of my applications yet. I'm having trouble really understanding the full concept, so I still have a few questions that I haven't found an answer to, so I hope that anyone can help me.
I want a user to be able to start my application (WP8), login to facebook / twitter / microsoft / ... .
When he gets authenticated, I want to actually save this user to my own DB so I can add some user specific stuff like preferences, posts, ... .
What do I need to save in my own DB to specify a user?
Do I need to save the token itself or is this something that will be invalidated after a while? Or do I need to specify the user's name? With other words: What can I use as a unique identifier?
And what happens when a user would authenticate with for example facebook and he deletes his account?
And one more question, would you ever allow a user to connect to an application with 2 different service providers? If so, how would you make the coupling of these 2 providers to 1 user in your own DB?
I hope my questions are clear enough!
If not, don't hesitate to ask for more information!
Kind regards,
Gert
I assume that you have your own back-end where you authenticate your own users and your WP8 application is just a client.
First, let me distinguish between a user credential and a user profile. User credential is something that validates who the user is, e.g. username/password, facebook user id supplied with a valid auth token. User profile, is what you store in your own database about the user.
You also need to distinguish between a token you use to authenticate the user and the AccessToken Facebook needs to grant you access to user's data.
So... to answer your questions:
What do I need to save in my own DB to specify a user?
Create a record with user data (like preferences, and your unique user ID), and user's login method (e.g. Facebook) and credential (e.g. Facebook's user ID). This is your user's profile.
Do I need to save the token itself or is this something that will be invalidated after a while?
You can also store the Facebook AccessToken here if you've been granted "offline access" privileges by Facebook, but that is used for Facebook's access by you... not by the user's access to your app/back-end. For user's access you could just use a mechanism similar to cookie-based authentication - it's up to you. You could use the AccessToken as a kind of a "cookie", but you would need to always check against Facebook that it's valid.
With other words: What can I use as a unique identifier?
You could treat Facebook's ID as unique (so long as you never allow another account in your user profile DB to link with the same Facebook account)
And what happens when a user would authenticate with for example facebook and he deletes his account?
It's a good idea to have users still create a username/password combination that works with you site and only rely on Facebook login for convenience. In any case, Facebook provides a "Deauthorize Callback URL" when you create an app profile on Facebook. This is called when a user deactivates your app or deletes an account with Facebook. When you receive this call, you could send your user an email when an auth link to setup a different credential so as to not lose access.
would you ever allow a user to connect to an application with 2 different service providers? If so, how would you make the coupling of these 2 providers to 1 user in your own DB?
Sure, you could do that. Say you'd want to allow a Twitter account as well. You'd need to add a Twitter user ID field to your user profile database.
Here's another tip: create an ASP.NET MVC4 project in Visual Studio - the template includes an example of how to set up a user profile database with OAuth login.
Hope it gives you the high-level overview to investigate further.
I am adding Twitter and Facebook login to a MVC 3 test application using TweetSharp and Facebook C# SDK.
Currently when a user signs in using Twitter I create a user account for that user in a user table and store the id, token, and token secret in a separate table with a foreign key to the user table. Since the id, token and token secret do not expire I can quickly locate the right user account when the user logs in next time using Twitter.
What if the very same user logs in using Facebook next time? Since Twitter does not provide email in their API and I therefore have no common piece of information to tie a user account to either Twitter or Facebook I assume I have to create a new user account for a Facebook login? Does anyone have any experience with this? Are there any ways to solve this?
I identify each user internally with a unique key. I check cookies for the user key when any user hits the site. If there's no cookie I create a new key. add it to the user database and set a new cookie. Once a user completes registration the first time by logging in with any of Facebook, Twitter or .Net membership , that key is forever married to that user.
So when an existing Twitter user logs in for the first time with Facebook, we know who they are because their user key exists. It is basically the same solution as macou suggested. Macou's has the plus of working on a new machine or if cookies are cleared, the cookie solution has the plus of not requiring additional user input.
Not really a solution, more of a work around. I was faced with the same problem and ended up forcing the user to complete thier account profile by asking for their email address before allowing them to proceed any further. This meant that if the email address coming back with the Facebook auth matched the email address created with the twitter signin then I didn't need to create another account.
The bigger difficulty was coming the other way, if the account was created by the facebook auth first. It meant an untidy marry up of accounts.
To be honest the information we got from allowing users to sign in with twitter was not worth the effort and in the end finished up only allowing Facebook auths. I'm not sure how important twitter is to your solution.
Not the perfect answer I know, but I thought I would share my experience.
You can't use just a cookie because I can login as facebook then my wife login as twitter using the same browser, you shouldn't link the two accounts in this case.
I think you need to do more than that:
Use a cookie then
Use name/first name/login name/... to see if they match.
Example:
Cookie id: 18459439731114330636, find user with id = 18459439731114330636. Found, go to 2, not found, go to 3.
Is username/first name/last name/... matches the current user? if yes, link accounts. if not, go to 3.
Create a new user.
I have recently implemented login to my via facebook connect. So now users have 2 ways of logging in to the site. The old way of registering an account and the new way (facebook connect).
One thing I would like to do is link a new facebook connect user account to existing accounts if they logged in the old way.
Has anyone had any success doing this?
Very good question I think and lots of people will benefit from an answer.
What you need to remember is that accounts are only linked so long as they are authorised to be linked through Facebook. What you should do is maintain a second table of linked accounts in your database so that you know who is who and if they are linked with Facebook.
You should read this integration comment, it provides a lot of useful information.
http://crazyviraj.blogspot.com/2010/01/test-cases-for-basic-facebook-connect.html
It doesn't really say how to do things, but it makes sure you tick all the boxes of what you should be doing.
ie:
Sign Up should fail if the user denies
permission to the app (category: sign
up)
Since we need access to an email
address, Sign Up should fail if the
user provides publish permission but
denies email permission (category:
sign up)
If the user provides an email address
that already exists in your system,
fail Sign Up. Make sure no YouFace
backend tables are modified (category:
sign up, 1:1 mapping) PS - when this
happens, I didn't find a way for you
to de-authorize YouFace on the
Facebook user's behalf. The user must
manually do this if they wish you use
the same account but provide a
different email address.
Accounts created using Facebook
Connect should not be able to login
using YouFace's default email/password
login system (category: sign in,
account security). PS: Since YouFace
accounts require a password and those
created using Facebook Connect don't,
make sure to insert a random password
hash into your table to avoid silly
errors
Accounts created using YouFace should
be able to sign in without requiring
to be signed into Facebook, even if
when a link to a Facebook accounts
exists (category: sign in)
Any many more
You should be asking for permanent access through fb connect authentication. Once you've done that, you'll get a token which gives your permission to access someone's Facebook information, and that token will not expire unless the user explicitly removes you from the permission list or changes his/her password.
Once you have the token, associate that token with the user / create a new field in your user table to store it.
To associate the user with a Facebook account without the user logging in, you can try to match by email. It's not 100% accurate but it's pretty good. Facebook doesn't give you email addresses in text form but you can get email hashes from FQL. Since you already know user email addresses, you can calculate the hash for all of your user emails and search through your user base for matches every time a new Facebook Connect user signs up.