Fine-Grained Access Control Using Keycloak Role Hierarchies

Question

Pulumi · Accepted Answer

Access control is a crucial aspect of any application or infrastructure, ensuring that the right people have the appropriate access to resources, based on the roles and permissions assigned to them. Fine-grained access control allows for a more detailed and specific assignment of these permissions.

Keycloak is an open-source identity and access management solution that provides fine-grained access control using role hierarchies, but configuring Keycloak for your applications typically involves a multitude of tasks including setting up realms, clients, roles, and users, and often falls outside the scope of what Pulumi directly manages. However, Pulumi can be incredibly helpful in automating the infrastructure deployment and setup processes around Keycloak itself and ensuring that the Keycloak service is integrated properly into your cloud architecture.

In this scenario, where we want to set up fine-grained access control using Keycloak, let's assume that:

- We have a Keycloak server running with the necessary realms and clients already configured.
- We want to deploy some cloud resources and configure IAM roles and policies for those resources.

We can use Pulumi to set up the cloud resources, IAM roles, and policies. For demonstration purposes, let's assume we want to create an AWS S3 bucket which should be accessible by users with a specific Keycloak role.

The AWS IAM Policy would define which actions are allowed on the S3 bucket, and we would associate this policy with an IAM role. Users or services that you want to have access to this bucket would assume this IAM role.

Please note that to integrate the access control fully, you would need a system that associates AWS IAM roles with Keycloak roles, which typically involves setting up trust relationships and identity federation. This integration is quite advanced and specific to your authentication setup but here is a simplified example of how you might define resources that enforce fine-grained access control.

```python
import pulumi
import pulumi_aws as aws

# Create an S3 bucket that follows best practices
s3_bucket = aws.s3.Bucket("secure-bucket",
    # The ACL here is private so that we can explicitly define who has access via policies
    acl="private",
    # Enable versioning for the best practice of data durability
    versioning=aws.s3.BucketVersioningArgs(
        enabled=True,
    )
)

# Construct an AWS IAM Policy Document that lists the permissions
# Replace the 'ROLE_NAME_HERE' placeholder with the appropriate role identifier
s3_bucket_policy = aws.iam.Policy("s3BucketPolicy",
    policy=pulumi.Output.all(s3_bucket.arn).apply(lambda args: json.dumps({
        "Version": "2012-10-17",
        "Statement": [
            {
                "Effect": "Allow",
                "Principal": {
                    "AWS": [
                        f"arn:aws:iam::{aws_account_id}:role/ROLE_NAME_HERE"
                    ]
                },
                "Action": [
                    "s3:GetObject",
                    "s3:ListBucket"
                ],
                "Resource": [
                    args[0],
                    f"{args[0]}/*"  # This allows access to the objects within the bucket
                ]
            }
        ]
    }))
)

# Output the names and ARNs of the resources we've created so they can be used elsewhere
pulumi.export("bucket_name", s3_bucket.bucket)
pulumi.export("bucket_arn", s3_bucket.arn)
pulumi.export("policy_arn", s3_bucket_policy.arn)
```

In this example:

- We've set up an S3 bucket with a private ACL to ensure that we finely control access.
- We've constructed an IAM policy document that grants specific read permissions to the objects in that S3 bucket. Replace 'ROLE_NAME_HERE' with the actual role name that you have configured in IAM that corresponds to a Keycloak role.
- We are exporting the `bucket_name`, `bucket_arn`, and `policy_arn` so that these can be referenced in further configurations or by other Pulumi stacks.

The actual association between IAM roles and Keycloak roles, where you would configure external identity providers in AWS IAM to trust Keycloak, is a manual step that needs careful set up in the AWS Management Console or through additional AWS IAM policies and trust relationships. Integrating that with Pulumi would require custom scripts or lambdas to automate federated logins, which is an advanced topic and could be the subject of another more detailed guide. Remember, when dealing with IAM and access control, great care should be taken to maintain security and follow best practices.