Need

Efficient resource allocation and management

Context

• Usage of Ruby for building dynamic and object-oriented applications
• Usage of Rails framework for building web applications

Description

Non compliant code

        class UsersController < ApplicationController
  def index
    @users = User.all
  end
end
        
        

In the above code, the index action of UsersController fetches all the users from the database. This is a very common operation in many applications. However, this approach can lead to severe performance issues if the number of users in the database is very large.

When User.all is called, it loads every single user into memory. This can consume an enormous amount of resources, especially if each user has a lot of data associated with it. If the server does not have enough resources to handle this operation, it could potentially crash or become unresponsive, affecting all users of the application.

Furthermore, this operation is performed regardless of whether all this data is actually needed. For example, if the index view only displays a few attributes of each user, loading every single user into memory is unnecessary and wasteful.

Finally, the lack of any sort of pagination or limit on the number of users fetched means that an external source (e.g., a user) could potentially cause the server to allocate a large amount of resources by simply accessing the index page.

Steps

• Implement pagination to limit the number of records fetched from the database.
• Use eager loading to optimize the database queries and reduce the number of database hits.
• Apply proper caching techniques to avoid unnecessary database queries.
• Implement input validation and sanitization to prevent malicious requests from consuming excessive resources.
• Consider implementing rate limiting or throttling mechanisms to restrict the number of requests processed per unit of time.
• Optimize the database queries and indexes to improve the performance of resource allocation.
• Monitor and analyze the resource usage to identify any bottlenecks or inefficiencies in the code.
• Regularly update and patch the Ruby on Rails framework to benefit from the latest security enhancements and performance improvements.

Compliant code

        class UsersController < ApplicationController
  def index
    @users = User.includes(:profile).page(params[:page]).per(10)
  end
end
        
        

The updated code now includes pagination and eager loading to address the improper resource allocation vulnerability.

Pagination is implemented using the page and per methods provided by the kaminari gem. This limits the number of records fetched from the database at a time, thus reducing the amount of resources consumed. The params[:page] is used to determine the current page number, and per(10) specifies that only 10 records should be fetched per page.

Eager loading is implemented using the includes method. This is used to load the associated profile records at the same time as the User records. This reduces the number of database queries made, thus reducing the amount of resources consumed.

In addition to these changes, it's recommended to implement input validation and sanitization to prevent malicious requests from consuming excessive resources. Also, consider implementing rate limiting or throttling mechanisms to restrict the number of requests processed per unit of time.

Optimize the database queries and indexes to improve the performance of resource allocation. Monitor and analyze the resource usage to identify any bottlenecks or inefficiencies in the code. Regularly update and patch the Ruby on Rails framework to benefit from the latest security enhancements and performance improvements.

References

• 067. Improper resource allocation