Rails Security - Enforcing ownership at the model level - ruby-on-rails

I recently coded up a 'friend' capability with my website. The way it works is if a user wants to 'friend' another user, sending a request creates a user_connection record with the original user set at the user_id and the requested user set as the contact_id. If the other user accepts the request, then another user_connection record will be made, with the user_id and contact_id reversed. If both user_connections exist, then the two users are considered friends. This currently gives each user access to any buildings shared between the two users.
I was wondering if there was some way I could enforce my user_connection model to make sure that whoever is creating the record gets set as the user_id. Otherwise it seems that someone could spoof the user_connection create request to make themself a contact of whomever they want, and then could spoof building shares using the same methodology. Are there any built in methods to prevent this?
My first thought was to have an initializer that always set the user_id to the current_user's id, but it appears that current_user is outside of the context of the model.

Don't allow user_id to be provided as a parameter, using strong params.
So, you could create the relation like that:
#friendship = current_user.friendships.new(contact_id: other_user.id)
Also make sure you provide the correct condition for current_user.
That's it... user_id is implied but never provided.

Related

How do associations affect the way we create objects in the controller?

I understand that associations are important because this gives us a way of linking two objects together so they have a 'relation' and we can query through both of them. For example,
A landing page belongs to a blog user & a blog user can have many landing pages
We obviously go into the models and apply the correct methods 'has_many' and 'belongs_to'. We also create a migration and add the foreign key to the 'belongs_to' model. This being the 'landing page'.
My problem:
When creating a landing page, it is possible to choose a blog user. This obviously passes the blog user ID into the params. I want to save this ID into the foreign key field in the landing page model.
Is this possible without doing:
def create
#landing_page = #blog_user.landing_pages.build(landing_pages_params)
end
Why do you have to go through a blog user? Another example:
def new
#landing_page = #blog_user.landing_pages.new
end
What is the purpose of doing it this way? Surely passing the ID into the field is enough without going through the blog_user?
Sure, you could do something like
#landing_page = LandingPages.new(blog_user_id: X)
Obviously, you need to know the ID of the BlogUser record. You'll then be able to access the newly associated BlogUser as you'd expect
#landing_page.blog_user #=> BlogUser(id: X)

Rails 5 access profile data anywhere in session without querying database each time

I've a user profile (with name, logo, about_me) which is created after user creation(using Devise). Profile table uses user_id as Primary key.
Now I want that whenever the user creates/updates a post, while filling in form some details are taken from profile, so profile data or #profile be available in post form as I cannot expose my model in form.
To set post.myname attribute in create and #update I'm doing this:
#myprofile = Profile.find_by_user_id(current_user)
write_attribute(:myname, #myprofile.name)
I read from various sources but what's the best solution of the 4 given and if anyone can back with easy code as I do not want to do something extensive? Thanks in advance.
1)Form Hidden fields - Like get the profile data as above in hash in #edit and then pass through form and access fields in #update but that way we will pass each field separately. Can one #myprofile be passed?
2)Session - I feel if profile data is stored in a session and someone updates profile then updated data won't be available in that session.So not sure if it is plausible.
3)Caching - easy way to do that?
4)polymorphic profile---tried it but I didnot get relevant example. I was stuck with what to put as profileable id and type and how to use them in the code.
If your Profile and User models have a one-to-one relationship with each other, the simplest solution is to remove the Profile model altogether and move its fields into the User model.
Devise already queries the database to obtain the current_user object. So, your example would like this:
write_attribute(:myname, current_user.name)
Which wouldn't hit the database (after Devise has retrieved the current_user object).
If you're forced to keep the Profile model, in looking at your four scenarios ...
You could use a session variable. Something like:
session[:profile_name] ||= #myprofile.name
This would go in a controller action.
The trick here is that you will want to redefine the each relevant session variable if the profile gets updated. And because you don't have access to the session in the model, you'd be best to perform that action in the controller. So, not pretty, but it could work.
You could also use low-level caching, and save the profile relationship on the user. In general, you could have a method like this in your user model:
def profile_cached
Rails.cache.fetch(['Profile', profile.id]) do
profile
end
end
Here, too, you will have to know when to expire the cache. The benefit of this approach is that you can put this code in the model, which means you can hook its expiration in a callback.
Read more about this in Caching with Rails.
I would avoid hidden fields and I'm not sure how a polymorphic relationship would solve you not hitting the database. So, #2 and #3 are options, but if you can combine the two models into one, that should simplify it.

Securely passing hidden id for nested forms on Rails

I have User and Profile models. User has_one Profile which belongs_to User. Profile also accepts_nested_attributes_for :user and I am building a form for Profile, which takes some attributes for user too.
In order to have my profile.user updated (not created), I must provide an id under the nested attributes for user form, which I do it through a hidden input.
The problem is that I don't think this is safe because one might change the id on the client side and the server would update another user instance, other than the profile's one.
To avoid this, on Profile's controller, I manually append the id for user_attributes on params which corresponds to the current_user.id, but I think that's not the best way to do it.
Is there any other way to ensure that Rails will be updating the actual profile's user or, in case the client supplies an user id different of its profile.user, it would prevent it?
If you are using a URI such as /user/123/profile you can obtain the user's id from the URI params and compare it to current_user.id if they match, great, if not, error.

Modelling multiple types of users with Devise and Rails 4

I have 3 types of "users"
Shop
Provider
Customer
The last 2 users will have similar attributes such as
First Name
Last Name
and so on
And the Shop user type will have the most contrast between types.
As far as behaviours they will all be quite different, although Provider and Shop will inherent many of customer behaviours.
It seems the behaviours can be dealt with CanCan as I've researched.
I'm now attempting to how I should authenticate these types.
I have looked at the STI model but I couldn't grasp where I would these extra attributes.
My mental model is as follower:
User is a table and model
The types are abstract models that inherit from this.
So I'm wondering, how do I add attributes such as Business address for just the Shop type?
Or is it that the User Table has a column called Type and that type is associated with these type tables? And within the type tables are the extra attributes?
Don't even bother bringing Devise into this; Devise is for authentication not authorization. Authentication is determining whether or not someone who visits your site is who you think they are, like logging in. Authorization is deciding whether or not a user is allowed to perform some sort of action, like creating a new post.
What you want to do is have some sort of system that assigns a normal user your three different types; CanCan will do something like that. One way to do this on your own is using a permissions number based system. Let's say normal users have permissions level at 100, shop has a level at 50, and provider at 25. Using this system you can determine what actions a user can perform without having to make separate models, which will make your schema unnecessarily complicated. Here's an example of how this would work with say the UserController:
def show
if current_user.permissions == 100
render "customer_show"
elsif current_user.permissions == 50
render "shop_show"
else
render "provider_show"
end
end
The easiest way to do this is to add a column to the user's table called permissions that defaults to say 100 when a new row is created. Here's what that migration would look like:
def change
add_column :users, :permissions, :integer, default: 100
end
As for authenticating, don't worry about it. Let devise do it's thing; every user, no matter what type, will login and sign up in the same way, maybe just having separate forms for each that has a hidden field to set the permissions level for that specific kind of user.
I know I'm late to the party but I'm putting this out for future SO searchers. You CAN authorize actions with Devise. If you have devise models for 'buyer' & 'seller' you can add 'buyer_signed_in?' for whatever action you only want buyers to be able to do. You can also do more specific role-based authorizations as well - check out Devise' page
All in all, Tsiege's solution sounds pretty interesting. Let us know if you had any success with it!

Pass Account ID to New User During Sign Up

Currenntly, my application is designed using Devise for authentication. I have it so when the first user signs up, an account is created in an Accounts table and the account_id is passed to the User table. I also have it set so that each time a new account is created that user is tagged as an admin. Finally, I have it working where the admin can create new users.
My problem is that at the time the new users are created I need to have these users be assigned the same account_id as the admin to tie the users together. I can do this if I add an account_id field on the form and have the admin manually enter it. What I want to have is that this is automated in the background.
I tried many varieties without success. This is one of the unsuccesful attempts where I put the following in the user.rb
before_save :add_account_id_from_parent
def add_account_id_from_parent
return true unless self.users.present?
self.users.update_attribute(:account_id, 1)
end
I used the number "1" just to see if I could get anything automated and placed in that field.
Like I said manually everything works, but I want it so the acocunt_id is automatically added during sign up based on the admins account_id.
I'm a bit confused why you are calling self.users. If I understand correctly, you want to assign account_id to 1 after a new user is created (as a test). You can do that like this:
before_save :add_account_id_from_parent
def add_account_id_from_parent
self.account_id = 1
end
You don't need to actually update the record since this is assigned before save, and save will write the new value to the db.
Again I might be missing something, if so please clarify.
UPDATE:
If you're validating that account is present, you'll need to change the callback to a before_validation instead of before_save, like so:
before_validation :add_account_id_from_parent

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