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1. Rails Generate Model Foreign Key
2. Rails Generate View
3. Rails Generate Secret_key_base For Development Plan
4. Rails Secret Key Base

Background

Generally in applications there are various secrets and credentials, that we need to make use of like API keys, secrets, etc.For such secrets we need the ability to conveniently and securely manage credentials.

Rails 5.1 added a feature to use secrets to manage credentials.

The multi/http/railsdoubletap exploit module has been added to the framework. This module can predict the secretkeybase to a Ruby on Rails application while it is running in development mode and use the secretkeybase to generate a serialized payload. Sending that payload back to the Rails application can then result in remote code execution.

Rails 5.2 replaced secrets with credentials, since encrypted and un-encrypted secrets were making it harder to manage them.

A set of files were used to manage these credentials:

• config/credentials.yml.enc
• config/master.key

config/credentials.yml.enc is an encrypted file which store the credentials. As this is a encrypted file, we can safely commit it to our version control systems.

config/master.key contains RAILS_MASTER_KEY which is used to decrypt the config/credentials.yml.enc. We should not commit this file to version control.

Interacting with credentials

As config/credentials.yml.enc is encrypted we should never directly read from or write to it. Instead, we will use utilities provided by Rails which abstract encryption and decryption process for us.

How to add/update credentials?

We can edit the credentials by running the following command:

Rails Generate Model Foreign Key

This will open a vim editor with the decrypted version of the credentials file.

We can add new credentials in YAML format. Lets add the following lines, save the changes,
and exit.

When we save it, it encrypts again using the same master key.

If default editor is not set and we haven’t specified the editor, then we get the following message:

How to read credentials?

We can now access the credentials in the following way:

Managing multi environment credentials before Rails 6

There was no built in support for multiple environment credentials before Rails 6. We could manage credentials for different environments but it was upto us to explicitly specify which set of credentials to use for a specific environment.

Strings come after numbers and are sorted lexicographically in ascendingorder. Children with a numeric value come next, sorted in ascending order. Firebase database generated primary key data. Ifmultiple children have the same numerical value for the specified childnode, they are sorted by key. If multiple children have a value of true, they aresorted lexicographically by key. Children with a value of true for the specified child keycome next.

We could store the credentials in a single file as below:

Then, config can be accessed using the following command:

There are some problems with this approach:

• There is just 1 master key and everyone on the development team had access to it. Which means everyone on the development team had access to production environment.
• We needed to explicitly specify which environment credentials to use in the code.

Another way to manage environment specific credentials was by creating environment specific files.For example, we can create config/staging.yml.enc for staging environmentand config/production.yml.enc for production environment.To read config from these files, Rails 5.2 providedencrypted method to support for managing multiple credentials files.

This approach involved writing even more boiler plate code to manage the keys and the encrypted files for every environment.

In Rails 6

Now, Rails 6 has added support for multi environment credentials.

It provides utility to easily create and use environment specific credentials. Each of these have their own encryption keys.

Global Credentials

The changes added in the above PR are backwards compatible. If environment specific credentials are not present then rails will use the global credentials and master key which are represented by following files:

• config/credentials.yml.enc
• config/master.key

We use the global configuration only for development and test environments. We share the config/master.key with our entire team.

Create credentials for production environment

To create credentials for production environment, we can run the following command:

The above command does the following:

• Creates config/credentials/production.key if missing. Don’t commit this file to VCS.
• Creates config/credentials/production.yml.enc if missing. Commit this file to VCS.
• Decrypts and opens the production credentials file in the default editor.

We share the production.key with limited members of our team who have access for production deployment.

Rails Generate View

Let’s add following credentials and save:

Similarly we can create credentials for different environment like staging.

Using the credentials in Rails

For any environment Rails automatically detects which set of credential to use.Environment specific credentials will take precedence over global credentials. If environment specific credentials are present, they will be used else Rails will default to global credentials.

For development:

For production:

Rails Generate Secret_key_base For Development Plan

Storing encryption key in environment variables

We can also set the value of the encryption key in specific environment variable Rails will auto detect and use it.

We can either use the generic environment variable RAILS_MASTER_KEY or an environment specific environment variable like RAILS_PRODUCTION_KEY

If these variable are set then we don’t need to create the *.key files.Rails will auto detect these variables and use them to encrypt/decrypt the credential files.

Rails Secret Key Base

The environment variable can be used for example on Heroku or similar platforms.