Can the Stack Overflow community sanity-check this for me?
I am working on a project that involves two components: an iOS app and a mobile website. It's for a product that will interact pretty heavily with Facebook. The website is hosted on Heroku.
From iOS land, my intention is to use the Facebook iOS SDK for authentication and then hit the web API with the user's access token at https://[myappname].herokuapp.com. Since Heroku offers piggyback SSL when using the herokuapp.com domain, and the user won't be seeing this URL anyway, I figure that's fine. And this way the request is encrypted, so the access token should be safe.
From the mobile website, users will log in using Facebook, at which point my understanding is that the access token will be in their cookies, which my server can then access without having to exchange it back and forth with each request. By this reasoning it seems to me I can just stick with regular unencrypted http:// URLs for the website (and therefore use my custom domain name without having to pay a monthly fee for Heroku's SSL Endpoint add-on).
Does this all make sense? I will be the first to admit my understanding of a lot of this stuff is in serious need of an upgrade. But for now I'm just looking for someone who can tell me, "No, you're totally overlooking/misunderstanding XYZ" or "Yeah, this is how it's generally done."
Facebook advises that you should not take a dependency on their cookie format. They have stated that the cookies are "an implementation detail" that they may tweak at any time with no notice given. You should not directly access the token or other user info directly from the cookie. I personally have had some bad experiences trying to get user information directly from the cookies, mostly due to timing -- they were not always there or updated when I expected them to be.
Client-side, you should either get the access token from the Javascript SDK via FB.getLoginStatus or other method that returns the access token, and then post it up to your server. This should really be done using ssl otherwise you are susceptible to network packet sniffing where a black hat could grab the token and be able to use all of the privileges the user granted your app.
There is also a server-side option as well which hits at ssl endpoint on Facebook's servers to return an access token.
References:
"Cookies are an implementation detail": https://developers.facebook.com/blog/post/624/
Authentication docs: https://developers.facebook.com/docs/authentication/
Website login via Facebook works totally fine via HTTP.
Related
I'm running a Classic ASP website, that has its own user authentication and login mechanism. For example, In order to remember a logged-in user, ASP creates an encrypted cookie and a 20-minute session for each connected user. If the 20 minute session is elapsed, the server revives the session from the cookie saved previously, and saves some data regarding the user to the database.
I want to to be able to allow users to connect with their Facebook or Google identity, but the mechanism used by Facebook or Google is based mainly on Javascript and on client-side code.
How Facebook or Google login can be used while maintaining server side code in ASP? (So that the ASP server can still manage the session and save data regarding it, for example whenever a session is revived)
For me somehow it seems that it may become less secure to use client-side authentication as the code may be altered easily. Isn't this the case?
If I use client-side javascript and log in with Facebook, how would I update the user data retrieved from facebook back into my database, for example the user's first and last name?
For me it sounds that it should be a "server-to-server" communication (between my ASP server and Facebook's or Google's servers) and what they propose is a "client-to-server" communication ... Any ideas how this can be done?
Any help or explanation would be very much appreciated! Thanks.
I'll try to address your Facebook-related questions one by one. However, I will not give you an implementation or any ASP-specific feedback, but only a rough approach. Additionally, I recommend that you study Facebook's documentation on Facebook Login extensively to further your understanding of the matter.
1. Facebook documents the server-side OAuth 2.0 flow in their Manually Build a Login Flow guide. Basically you redirect the user to a specific FB URL that (in the parameters) tells FB to render the "Login with Facebook" dialog, and which permission scopes to ask for. Once the user approves the Facebook Login for your webapp, they will be redirected back to your web app, e.g. with an OAuth token in the query string, that your webserver can then exchange for a user access token.
Once you obtained a user access token, you could e.g. store it in your web app user's session.
2. I don't know what you mean. Client side apps are fairly secure. Perhaps you can convince yourself about how secure JS apps are when reading about things like CORS.
3. If you only use JavaScript (e.g. Facebook's JS SDK) and you want to store e.g. app-scoped user IDs on your server, you need to expose an endpoint on your server that your JS application can submit that kind of information to.
4. You state
what they propose is a "client-to-server" communication
Who are "they", and where are the proposing this? The resources I linked to in 1. should explain how you can use Facebook login in a pure server-to-server way.
I'm trying to build a Facebook-authenticated native mobile app (Windows Phone) that connects to a web service I am creating in Node.
I'd like for a user to:
Log in to Facebook on the mobile app via a native UI or web window
If logged in successfully, create or access server-side user account data tied to that identity
Use the authenticated session to make subsequent authenticated requestsvto that user's data via the native mobile app
My question is: What's the best approach here?
Should I...
Log in the client to facebook locally in the mobile app and pass the Access Token to the node service, and then somehow map the user to my service data based on their facebook account id? That seems grossly insecure if I just pass that token in the URL.
Log the user in via a mobile browser window inside my app, and then redirect back to my Node service in the same window? How do I then make subsequent authenticated requests natively in my app?
Do something else entirely?
Sorry this is so open ended but this is the first time I have tied these things together and although there's a lot of info on each part I've yet to find something that describes the overall pattern / best practice for this design.
Your question is quite opinion based...but still I will try to help.
First of all, you can pass access token in url, its not insecure if you use https. Even if logged into facebook from your mobile app, than also its going to pass a access token in url only. If you mean having the token in http://something.com/access_token, than its not how its should be done.
If you look into the Oauth 2.0 draft you will understand that its done through setting a header Authorization with the value being the token and token_type. Take a good look at the draft.
As your solution I think its fine if you just use the first method mentioned in the question by sending the access token in header as I mentioned in your app and in turn authenticating that token from facebook on each request.
If you think this is just too long a flow for authenticating every request from facebook, than you can get access token by sending request from your mobile app to server and let the server handle the access token and store it in database which you can authenticate each request.
In any case take a look at Passport module, it has facebook and other auth built-in and should be sufficient for your needs.
My question is related to, but not exactly, this question.
I am currently working on a business directory Web site (similar to Yelp), in which businesses have their own pages. Let's call this app DIRECTORY_APP.
Businesses might want to have their latest Facebook status update shown on their pages hosted on our directory. Let's pretend we have a business named BIZ_1. The assumption is that those pages are public pages.
Apparently the Facebook Graph API can be used for this purpose. So I can send a request to Facebook to retrieve the latest status updates for BIZ_1:
https://graph.facebook.com/BIZ_1_PROFILE_ID/posts?
access_token=DIRECTORY_APP_ACCESS_TOKEN
&callback=callbackName
However, if I use this from the client side, our Web site's access token will be exposed to the public, so this is not a reasonable solution.
Now in the aforementioned question, Anatoly mentions that we can retrieve the access token by sending this request first:
https://graph.facebook.com/oauth/access_token?
client_id=YOUR_APP_ID&client_secret=YOUR_APP_SECRET
&grant_type=client_credentials
However if someone inspects the Network log, this will also expose our Web site's access token (is this correct or is this a different type of access token?). This solution also exposes our web site's app secret (is this safe?).
So to summarize, what's a safe way in which I can retrieve the latest status update of a Web page from client-side without asking the browsing user to first log in to Facebook?
I can retrieve the latest status update of a Web page from client-side without asking the browsing user to first log in to Facebook
You cant do that without login.
And I guess access token is not exposed.
Maybe the smart trick here is to use a social plugin. The Like Box will do what you want, without any issues. But, it's not greatly customizable. Even so, it's possible to get it looking nice on a page!
It also skips any login issues you mentioned.
I found the answer after some Googling. In short, the answer is no.
And here's an excerpt from Facebook:
Security Best Practices
App Secret and App Access Token
The App Secret is used in some of the Login flows to generate access tokens and the Secret itself is intended to secure usage of your App to only those that are trusted. The secret can be used to easily create an App Access Token which can make API requests on behalf of any user of the app, which makes it extremely important that an App Secret is not compromised.
Therefore the App Secret or an App Access token should never be included in any code that could be accessed by anyone other than a developer of the app. This applies to all methods of code that are not secured like client-side code (such as HTML or Javascript) or native apps (such as iOS, Android or Windows desktop apps) that could be decompiled.
We recommend that App Access Tokens should only be used directly from your app's servers in order to provide the best security. For native apps, we suggest that the app communicates with your own server and the server then makes the API requests to Facebook using the App Access Token. For this reason, if your 'App Type' under Advanced Settings in the App Dashboard is set to Native/Desktop we assume that your native app contains the App Secret or an App Access Token in the binary, and we do not allow calls signed with an App Access Token to proceed. The API will behave as though no access token was provided.
If your App Secret is compromised, you should reset it immediately in the Basic Settings of your App Dashboard.
Is OAuth sensible to use when the user account info (user id's, passwords, roles, etc) is going to be maintained in our own back-end and when there will not be any sharing of resources with other sites? Or is sharing the whole point of using OAuth?
Background:
I'm working on developing an enterprise SaaS product and we are creating a RESTful API to be used by our front-end applications. Consumers of the API will be browser and native smartphone (iOS & Android) applications that we develop. Since we'll be supporting multiple client types, it makes sense to create a RESTful API that all our client apps can consume.
Naturally we need to secure this RESTful API. We are considering authenticating using HTTPS / Basic Auth but we are aware of some of the well known drawbacks to this approach.
Some quick research shows OAuth is highly recommended. But most of what I find with OAuth is in the context of authorizing web sites to share information on behalf of the user.
Any info if most welcome.
Good question, and we're having a good discussion on this over at API Craft:
https://groups.google.com/group/api-craft/browse_thread/thread/b87fd667cccb9c00
Here's the answer that I posted there:
I think this is a good use case for OAuth, actually.
First of all, with OAuth your mobile app can store an OAuth token on the client rather than the user's "real" password. So, you can have the app automatically "log the user in" by getting an OAuth token without having to store the actual password on the device. If the user loses the device or if it's compromised somehow they (or you) can wipe the OAuth token without requiring that the user change the password and blow away other things that they might be doing with your API. There are similar examples for an Ajax-style web app but it depends more on the specific way that you build the client.
Second, the OAuth token is associated with a unique key that identifies the app that is making the API call, and that in turn identifies which developer built the app. That gives you options like tracking usage by application, turning off an application that might have been compromised without disabling the whole API, and if you ever want to open access to third parties or partners who build apps for your API, you can offer different levels of service to other customers.
Third, your IT security people will be happy if you tell them that you never store a password on the user's mobile device or stash it somewhere in their browser.
Fourth, you have the option of browser-based login for the mobile app. That means that the mobile app will never see the user's password, and also that if you want to implement two-factor security or something like that, you can do it in the login screen without changing the mobile apps. Now, the downside is that the user sees a browser window pop up. That's why OAuth gives you a few different ways to get an access token for an app, so you can choose whether you need to have browser-based login or have the user enter their password directly in the app.
Fifth, how do you know that your API will only ever be used by your own apps? If you use OAuth now then you will have an easier time making that transition later.
Yes, this is a very good fit for OAuth. You can still use HTTP Basic over SSL during the handshake for authentication. The output of the OAuth handshake will be a token which can then be used to consume the API. This way, the application does not need to store the credentials and tokens can easily be revokes with minimal user impact.
OAuth 2.0 defines a number of different grant types for accommodating different situations. It sounds to me like the 'implicit' or the 'resource owner password credentials' are the most appropriate but you may want to consider each carefully.
You should not implement this directly in your API but use infrastructure to delegate the OAuth support and token management on behalf of your SaaS API instead.
Take a look at
http://www.layer7tech.com/blogs/index.php/oauth-token-management-2/
and
http://www.layer7tech.com/products/oauth-toolkit
Hope this help,
-fl
I implemented an OAuth for Django nonrel with piston to expose my APIs to consumer. There are a number of kind in OAuth(2-legs 3legs).
Generally, supporting OAuth is quite a bit challenge. You have to obtain the request token, authorize it, store the access token to sign every request you want to authenticate.
Advantages
- You don't have to send username and password everytime, secure.
- Enable third party to consume your app.
Disadvantages
- Make 2,3 round trips to authenticate.
- Complicated to implement it by yourself.
I'm pretty sure that you can find a number of library that allow you to:
- Expose your Api and support OAuth. E.g Django piston.
- Sign your requests by adding headers to them. E.g Oauth-signpost.
OAuth is only a token and the requesting App will issue one. You can read more in pingidentity.com where there are several webinars on this topic(cloud identity and user provisioning) as well.
TL;DR version:
Can you authenticate with Facebook without having a callback URL for a web application since the web application isn't actually running on a server.
Full explanation:
I'm working on building a connectedTV platform application where the "app" itself is a bunch of HTML/JS/CSS running locally (like File -> Open on your desktop browser) and I'd like to integrate Facebook into this.
The problem is that all of Facebook's OAuth calls for the web require you to have a callback URL to redirect the user to in order to complete authentication. Here's the gotcha -- there is no URL for this application -- it's a locally running webpage on the device.
I know this is what out-of-band authentication was designed for, but I can't seem to find any documentation on how to use this (or how to do a non-callback OAuth flow) with the Facebook OAuth system.
You're describing desktop authentication or any situation where you are authenticating to FB without a server. The redirect URL you pass to the OAuth dialog is https://www.facebook.com/connect/login_success.html When the browser redirects you can get the access token. You can read all about it in the FB documentation, way at the bottom in the Desktop Apps section (https://developers.facebook.com/docs/authentication/)
Just reread your question and since the application runs inside a browser you will need to open another window to authenticate and get the access token from that.
If you're doing HTML/Javascript, use their Javascript SDK. You can log the guy in simply by using FB.login and getting the access token from the callback from that.
I really don't think this is directly possible. Unless there is something totally undocumented, Facebook has no mechanism to send authentication data except by loading a url. I'm sure it's meant at least partly as a security measure, functioning as sort of a "whitelist" of where auth data will be sent.
The only way I can think of for you to work around it might be to set up a url on a server somewhere that could answer the redirect and store the auth data, and have your client-side code poll that server to get it. Kind of a proxy authentication service, in effect. You would probably have to open a second browser window with the Facebook auth screen in it, but in theory it could work.