Enforcing Compliance in Machine Learning Workflows with AWS S3 Bucket Policies

Question

Pulumi · Accepted Answer

## Enforcing Compliance with AWS S3 Bucket Policies

When working with Machine Learning (ML) workflows, one crucial step is to ensure that the data used in these processes is handled in compliance with various requirements. This can include policies on who can access the data, how it's used, and ensuring that the data is encrypted in transit and at rest. With AWS, compliance can primarily be enforced through S3 Bucket Policies.

AWS S3 Buckets are highly durable storage containers where you can store vast amounts of data. With S3 Bucket Policies, you can define permissions to regulate who can access your buckets and objects within them. These policies enable you to enforce compliance by explicitly allowing or denying different actions on the S3 buckets.

Let's look at creating an S3 Bucket with a policy that enforces server-side encryption with a specific AWS Key Management Service (KMS) key. This is a common compliance requirement to ensure that any data stored in the bucket is encrypted using a managed key.

Here's a step-by-step Pulumi program that will:

1. Create an AWS S3 bucket.
2. Apply a bucket policy which enforces the use of server-side encryption with AWS KMS for all objects in the bucket.

```python
import pulumi
import pulumi_aws as aws

# Create an AWS KMS Key for bucket encryption
kms_key = aws.kms.Key("my-key",
                      description="KMS key for S3 bucket encryption")

# Create an AWS S3 Bucket
s3_bucket = aws.s3.Bucket("my-bucket",
                          server_side_encryption_configuration=aws.s3.BucketServerSideEncryptionConfigurationArgs(
                              rule=aws.s3.BucketServerSideEncryptionConfigurationRuleArgs(
                                  apply_server_side_encryption_by_default=aws.s3.BucketServerSideEncryptionConfigurationRuleApplyServerSideEncryptionByDefaultArgs(
                                      sse_algorithm="aws:kms",
                                      kms_master_key_id=kms_key.id))))

# Define the policy
bucket_policy = aws.s3.BucketPolicy("my-bucket-policy",
                                    bucket=s3_bucket.id,
                                    policy=pulumi.Output.all(s3_bucket.arn, kms_key.arn).apply(lambda args: json.dumps({
                                        "Version": "2012-10-17",
                                        "Statement": [
                                            {
                                                "Sid": "RequiredEncryptedPutObject",
                                                "Effect": "Deny",
                                                "Principal": "*",
                                                "Action": "s3:PutObject",
                                                "Resource": f"{args[0]}/*",
                                                "Condition": {
                                                    "StringNotEquals": {
                                                        "s3:x-amz-server-side-encryption": "aws:kms",
                                                        "s3:x-amz-server-side-encryption-aws-kms-key-id": args[1]
                                                    }
                                                }
                                            }
                                        ]
                                    }))
                                    )

# Export the name of the bucket
pulumi.export('bucket_name', s3_bucket.id)
```

### Explanation

In the above program:

- A KMS Key is created, which will be used to encrypt the data in our S3 Bucket.
- An S3 Bucket is instantiated with server-side encryption configuration set to use the KMS Key.
- A Bucket Policy `my-bucket-policy` is applied to the created bucket. It denies the put object operations (`s3:PutObject`) that do not use our specified KMS Key for server-side encryption. This ensures that any object put in the bucket without the required encryption settings will be rejected, thus enforcing our compliance requirement.
- In the policy, `Condition` checks for requests that do not match our encryption criteria. If the conditions are met, meaning incorrect encryption settings are used, the request is denied.
- Lastly, we export the bucket name for reference.

With this setup, you can be confident that your ML workflows are using an AWS S3 Bucket that enforces the required compliance automatically, thanks to the bucket policy.