In an environment where a very big online application/web is divided into subdomains:
app1.mydomain.com
app2.mydomain.com
Each app is able to handle its subdomain session cookie.
However, in order to mantain certain data live through all apps, like session provider and account information in a multi-single-sign-on environment, it would be useful to also store/access session cookies at a domain level:
mydomain.com
What would be the best approach to handle simultaneously domain level and subdomain session cookies in Ruby on Rails? One issue would also be that this domain level cookie should be encrypted with the same hash across all applications/subdomains, which can be done, but doesn't fully integrate with Rails session design, unless all application share their secret token.
Best I could think of is use Rails default session handler for subdomain cookies, and create manually a domain level cookie handler, however it would be cool to be able to use session and domain_session as it is designed to be used more easily, though this is not a common issue.
Related
I'm adding oauth support (via omniauth) to a legacy Rails app. One complication to this app is that it uses subdomain-based multitenancy (for example account1.example.com, account2.example.com) and when registering our app with oauth providers, we need to specify full URLs for our callback — no wildcard domains allowed.
No problem, I'll just reserve oauth.example.com and register that.
The problem, though, is that our session ID cookies are set for account1.example.com and such. This makes CSRF protection break and also makes passing along the client's destination a lot tricker.
I can reconfigure our Rails app to set the session ID cookie on .example.com which fixes the CSRF issue. But! If I change that in production, it will invalidate every session for every user of our app. Not a showstopper, I guess, but pretty unfriendly.
So! As the only place I want to share cross-domain sessions is for our oauth actions — is there a way I can override the session handler on a per-controller basis?
Or would I maybe be looking to write a custom Rack middleware to override session handling for some requests…?
I have two models doing login (Devise) in my Rails app - Admin and User, both currently use the default cookie store for session data.
I want to be able to identify an Admin session in AJAX requests coming in from the admin, for authorization of these API calls. I plan to do this by setting an encrypted cookie upon Admin login. When the AJAX API call comes in, I open the cookie, grab some identification from it and look for a matching existing Admin session in the store.
As I understand it, to do this, I must have session information stored in the back-end, either by DB or memcache stores.
I expect to have millions of sessions of Users and just a few sessions of Admin at any given time. For this reason, I don't want to just move all session information to a DB or memory, since this is a heap of unneeded data to store. I only want to store/look at Admin session data.
A solution will be creating some custom model which enumerates Admin user sessions, and is maintained by the app. This is simple enough but requires for instance, a way to clean up sessions when they die without signing out. Essentially this is an attempt to duplicate Rails's session store mechanism, which comes with all the problems of storing and maintaining sessions. Instinct tells me to avoid this solution. Am I correct to avoid it?
If so, then my question is, is there a way to configure multiple session stores in a Rails app, a different store for every logged in Model? In this case, have Admin sessions stored in memory, and User sessions stored in cookie. If not, I'll greatly appreciate any comments and suggestions.
Thanks!
You may be thinking about it wrong.
Session are a low level mechanism that you build your authentication on top of. Its just a cookie containing an identifier (a random hash) which is linked to a session storage (by default cookies). This is a simple mechanism to add persistence to a stateless protocol.
Confusingly we also use the concept "sessions" when talking about authentication - for example logging a user in is often referred to as "creating a session". This is complete poppycock as we are just storing a claim (often a user id) in the session that was created when the user first visits the application.
If so, then my question is, is there a way to configure multiple
session stores in a Rails app, a different store for every logged in
Model?
No. Thats a chicken-vs-egg conundrum. In order to know which session storage to use you would need to access the session storage to know which session storage to use... you get the picture.
While you could create your own session storage mechanism that works differently does this is most likely a complete waste of time. Premature optimization is the root of all evil.
As I understand it, to do this, I must have session information stored
in the back-end, either by DB or memcache stores.
Not quite true. You can perfectly well build an authentication solution with just the cookie storage. In that case Rails just keeps a record on the server of which session identifiers are valid.
The main reason you would need to store additional session information in the database or memcached is if you need to store more data in the session than the 4093 bytes allowed by a cookie. Cookie storage is after all much faster and does the job fine 99% of the time. YAGNI.
You should also recognize that not everything needs to be saved in the session storage. For example the Devise trackable module saves log in / out timestamps on the user table as part of the process of authenticating a user. This is "session information" yet has nothing to do with session storage.
I want to be able to identify an Admin session in AJAX requests coming
in from the admin, for authorization of these API calls.
There are many ways to use different authentication logic for different parts of the application such as Warden strategies. For an API you may want to consider using stateless (and sessionless) authentication such as JWT.
I'm trying to figure out how ASP.NET internally validates that a cookie will allow the user to access the application.
CookieAuthenticationMiddleware will set .AspNet.Cookies with an encrypted value. After .NET successfully decrypts the cookie on a request, what validation occurs then?
Developing locally with IISExpress if I have an application (#1) that sets an authentication Cookie after the user logs in, and I create a complete new application (#2) also running on localhost, that is also using CookieAuthentication. When I access #2 it will read the cookie from #1 and allows the user to access the application as well.
I'm trying to understand what the limits are for cookie authentication.
There's not really any "validation" per se. The cookie's encrypted key is used to reference the user that should be "logged in". It works in a very similar way to sessions, where the session cookie holds an encrypted session id that the server can use to look up and restore the session via.
The encryption/decryption is based on the machine key, which either may be explicitly set in the Web.config or generated automatically by ASP.NET. Only applications that share the same machine key may decrypt the cookie, which is why it's so important to protect your machine key.
Anyways, there's two factors involved here. First, cookies are domain bound: only the domain or subdomains of the domain the cookie is set on will be given the cookie. This is handled by the client (i.e. browser). Your two applications currently are able to both see the cookie because they're both running on localhost. However, if you were to deploy one at foo.com and the other at bar.com, then they would no longer be able to see each other's cookies.
Second, the machine key is typically by server (unless you explicitly set it in the Web.config per app). As a result, sites running on the same machine can usually decrypt each other's cookies (assuming they see them in the first place, which again, is based on their domain).
It's not clear whether you're happy or not about this arrangement. If your goal is to segregate the two sites running locally, such that they don't share cookies, you have a couple of options.
You can explicitly set a different machine key for each site in their respective Web.config files. They'll still receive any cookies set by the other site, but they'll no longer be able to decrypt them, which basically results in them being ignored.
You can customize the auth cookie name. Instead of using the default cookie name you can make one .Site1.Auth and the other .Site2.Auth. Then, even though either site will also receive the cookie for the other site, it will simply ignore it, because it's not the auth cookie for it.
If, however, you're intending to rely on this behavior in production as well (i.e. you actually want logging into one site to log you into the other as well), then you'll need to explicitly set the machine key to the same value in both site's Web.config files. Additionally, you'll need to deploy them on the same domain, or at least subdomains of that domain. In the case of subdomains, you'll need to set the cookie domain to be the wildcard domain .mydomain.com for both. Then, you could have one at foo.mydomain.com and another at bar.mydomain.com, and they'd both see the cookie because it was set on .mydomain.com. If you leave it the default, set on the actual domain of the site, then bar.mydomain.com could not see a cookie set by foo.mydomain.com because that cookie would be explicitly set only for foo.mydomain.com.
The primary validations are encryption and expiration. If apps share an encryption context (e.g. machine key) then they can share auth cookies (providing other client side sharing rules like domains and paths are satisfied). So yes it's expected that two apps using IIS Express localhost on the same machine would share cookies by default.
The expiration is also embedded in the encrypted value so the client can't tamper with it.
We are designing an application that will use Rails and Wordpress to interact with each other. We would like to have a universal logout where you could logout from either application and it would delete cookies from the other app. They will share the same host and toplevel domain. Is there a way to do this?
Access to a cookie is dependent on the domain of the server attempting to read the request -- and potentially the domain specified in the cookie. So assuming the domains match (e.g. www.example.com and www.example.com on both blog and Rails app) either should have access to a cookie set by the other.
If this is not the case (e.g. blog.example.com, www.example.com), you'll need to make sure when the cookie is set in either place, it's set for the entire domain (e.g. .example.com). But this doesn't help: while Rails can delete WP's cookie, and vice-versa, the method for creating (and using) them needs to be mutually understood.
So there's a twist here, since this is a session cookie; in this case, the cookie (which either app should have access to) is setting a value that is used and interpreted on the server side, where sessions are managed. WordPress and Rails both different methods and look for different cookies.
A solution (idea) would be to have one or the other subsystem catch incoming requests (most likely WP, and probably through some .htaccess RewriteRule, assuming you're using Apache) and create an intermediate cookie that the other could check that provides sufficient proof that the user has logged in correctly. WP's PHP for this is pretty good, and easily extended -- you just need to create some token that's a shared secret between the two apps (one of the values in wp-config.php such as LOGGED_IN_KEY might be a good option).
Maybe a solution would be to take the publicly available value from the WP cookie for username, and append the shared secret value and (in both systems) create an MD5 hash to store in a cookie. In this case, Rails' authentication would subordinate to WP's, so you would need to make sure Rails knew to delegate things like forgotten password, changed password, etc, to WP's mechanisms.
Obviously I am thinking aloud, but maybe this is a path to consider.
In any case, this is preferable to having both systems know how to trust the other's authentication.
Fiddling with cookie deletion appears to be dirty and error prone.
You might rather want to have a look at auth providers and the according plugins such as:
OAuth (WP - Rails; maybe make either side an OAuth provider)
CAS (WP - Rails)
LDAP (WP - Rails)
...
Maybe it's an option to switch from WP to one of Rail's CMS like:
Refinery CMS
Typo
...
is it true that Rails depend on cookies? It seems that flash is a part
of session, and session uses cookies... so when i disable cookie in
Firefox, a Rails app that was working shows
[error]
ActionController::InvalidAuthenticityToken
so is it true that for a RoR app to work, cookies are mandatory?
Update: or, to make the Rails app work again, what is the simplest way? (and if it is one server only (Apache running mod_rails), then is it easier?)
They are not mandatory, but there are some things you can't do without cookies. You can turn the authenticity tokens off as described here.
It's not mandatory to use cookies, but it is the rails default from 2.x up. Using cookies serves as a simple solution to some more difficult problems that arise when you try to store cookies in memory on multiple servers (and you get into things like sticky sessions, losing user data etc).
You can set where rails stores your session data; that is the flash and anything that's associated with the specific user. In environment.rb you can configure where you store your sessions using the config.action_controller.session_store. The options for this are: :cookie_store, :active_record_store, :p_store, :drb_store, :mem_cache_store, or :memory_store.
cookie_store is the default, if you comment the option out or remove it from environemnt.rb. It's also the most versatile. If you have multiple servers, one request for a user might come into one server, and the next request might come into a different server. In this situation, you couldn't use memory_store, as the 2nd server wouldn't know anything about the current user.
By storing session information in an encrypted cookie, there is less load on the server to store this information. The only downside is that each request to the server needs to pass the cookie (usually <1k), but it's not a noticeable difference in anything I've ever experienced.
:cookie_store, :mem_cache_store and :active_record_store are the most commonly used ones.