Extend Access to a Private S3 Bucket Using Python

Extend Access to a Private S3 Bucket Using Python

Kenneth Bingham's photo
Kenneth Bingham
·

2 min read

A private S3 bucket protects against a data leak by denying all public access. This approach moves access control from the public S3 API to the network layer. We can use OpenZiti's cryptographic identity and attribute-based policies to securely extend access to a trusted Python program at a remote site.

The OpenZiti Python SDK (import openziti) makes it easy to use the AWS Python SDK (import boto3) through an OpenZiti tunnel using only Python. No sidecar, agent, or client proxy is needed!

Here's an example of a bucket policy that allows any S3 bucket action for any AWS caller identity as long as the request arrives via the VPC endpoint (VPCE).

{
   "Version": "2012-10-17",
   "Id": "Policy1415115909152",
   "Statement": [
     {
       "Sid": "Access-to-specific-VPCE-only",
       "Principal": "*",
       "Action": "s3:*",
       "Effect": "Deny",
       "Resource": ["arn:aws:s3:::awsexamplebucket1",
                    "arn:aws:s3:::awsexamplebucket1/*"],
       "Condition": {
         "StringNotEquals": {
           "aws:SourceVpce": "vpce-1a2b3c4d"
         }
       }
     }
   ]
}

from Restricting access to a specific VPC endpoint

Consider this Python script that uploads a file to a private S3 bucket. This must run inside the trusted VPC to reach the private IP address of the VPCE (i.e., Privatelink Interface).

from boto3 import client

s3 = client(service_name='s3', endpoint_url=bucket_endpoint)

s3.upload_file(file_path, bucket_name, file_name)

We can extend trust beyond the VPC to securely perform bucket actions from anywhere. This next example patches the S3 client to tunnel to the bucket endpoint with OpenZiti securely.

from boto3 import client

import openziti

s3 = client(service_name='s3', endpoint_url=bucket_endpoint)

openziti.load(ziti_identity_file)

with openziti.monkeypatch():
    s3.upload_file(file_path, bucket_name, file_name)

These Python snippets are representative of a functioning sample, s3z.py (link to OpenZiti Python SDK). The README contains a list of the AWS and OpenZiti entities and configurations that make this possible.

Share the Project

If you find this interesting, please consider starring us on GitHub. It helps. Let us know if you found a good use for this or have an improvement or question in mind on X twitter, in /r/openziti, or the Discourse forum. We upload and stream on YouTube too. We'd love to hear from you!

Pythonboto3