S3 / Client / put_bucket_policy



Applies an Amazon S3 bucket policy to an Amazon S3 bucket.


Directory buckets - For directory buckets, you must make requests for this API operation to the Regional endpoint. These endpoints support path-style requests in the format ``https://s3express-control.region_code.amazonaws.com/bucket-name ``. Virtual-hosted-style requests aren’t supported. For more information, see Regional and Zonal endpoints in the Amazon S3 User Guide.


If you are using an identity other than the root user of the Amazon Web Services account that owns the bucket, the calling identity must both have the PutBucketPolicy permissions on the specified bucket and belong to the bucket owner’s account in order to use this operation.

If you don’t have PutBucketPolicy permissions, Amazon S3 returns a 403 Access Denied error. If you have the correct permissions, but you’re not using an identity that belongs to the bucket owner’s account, Amazon S3 returns a 405 Method Not Allowed error.


To ensure that bucket owners don’t inadvertently lock themselves out of their own buckets, the root principal in a bucket owner’s Amazon Web Services account can perform the GetBucketPolicy, PutBucketPolicy, and DeleteBucketPolicy API actions, even if their bucket policy explicitly denies the root principal’s access. Bucket owner root principals can only be blocked from performing these API actions by VPC endpoint policies and Amazon Web Services Organizations policies.

  • General purpose bucket permissions - The s3:PutBucketPolicy permission is required in a policy. For more information about general purpose buckets bucket policies, see Using Bucket Policies and User Policies in the Amazon S3 User Guide.

  • Directory bucket permissions - To grant access to this API operation, you must have the s3express:PutBucketPolicy permission in an IAM identity-based policy instead of a bucket policy. Cross-account access to this API operation isn’t supported. This operation can only be performed by the Amazon Web Services account that owns the resource. For more information about directory bucket policies and permissions, see Amazon Web Services Identity and Access Management (IAM) for S3 Express One Zone in the Amazon S3 User Guide.

    Example bucket policies

General purpose buckets example bucket policies - See Bucket policy examples in the Amazon S3 User Guide.

Directory bucket example bucket policies - See Example bucket policies for S3 Express One Zone in the Amazon S3 User Guide.

HTTP Host header syntax

Directory buckets - The HTTP Host header syntax is s3express-control.region.amazonaws.com.

The following operations are related to PutBucketPolicy:

See also: AWS API Documentation

Request Syntax

response = client.put_bucket_policy(
  • Bucket (string) –


    The name of the bucket.

    Directory buckets - When you use this operation with a directory bucket, you must use path-style requests in the format https://s3express-control.region_code.amazonaws.com/bucket-name ``. Virtual-hosted-style requests aren't supported. Directory bucket names must be unique in the chosen Availability Zone. Bucket names must also follow the format ``bucket_base_name--az_id--x-s3 (for example, DOC-EXAMPLE-BUCKET--usw2-az1--x-s3). For information about bucket naming restrictions, see Directory bucket naming rules in the Amazon S3 User Guide

  • ChecksumAlgorithm (string) –

    Indicates the algorithm used to create the checksum for the object when you use the SDK. This header will not provide any additional functionality if you don’t use the SDK. When you send this header, there must be a corresponding x-amz-checksum-algorithm or x-amz-trailer header sent. Otherwise, Amazon S3 fails the request with the HTTP status code 400 Bad Request.

    For the x-amz-checksum-algorithm header, replace algorithm with the supported algorithm from the following list:

    • CRC32

    • CRC32C

    • SHA1

    • SHA256

    For more information, see Checking object integrity in the Amazon S3 User Guide.

    If the individual checksum value you provide through x-amz-checksum-algorithm doesn’t match the checksum algorithm you set through x-amz-sdk-checksum-algorithm, Amazon S3 ignores any provided ChecksumAlgorithm parameter and uses the checksum algorithm that matches the provided value in ``x-amz-checksum-algorithm ``.


    For directory buckets, when you use Amazon Web Services SDKs, CRC32 is the default checksum algorithm that’s used for performance.

  • ConfirmRemoveSelfBucketAccess (boolean) –

    Set this parameter to true to confirm that you want to remove your permissions to change this bucket policy in the future.


    This functionality is not supported for directory buckets.

  • Policy (string) –


    The bucket policy as a JSON document.

    For directory buckets, the only IAM action supported in the bucket policy is s3express:CreateSession.

  • ExpectedBucketOwner (string) –

    The account ID of the expected bucket owner. If the account ID that you provide does not match the actual owner of the bucket, the request fails with the HTTP status code 403 Forbidden (access denied).


    For directory buckets, this header is not supported in this API operation. If you specify this header, the request fails with the HTTP status code 501 Not Implemented.




The following example sets a permission policy on a bucket.

response = client.put_bucket_policy(
    Policy='{"Version": "2012-10-17", "Statement": [{ "Sid": "id-1","Effect": "Allow","Principal": {"AWS": "arn:aws:iam::123456789012:root"}, "Action": [ "s3:PutObject","s3:PutObjectAcl"], "Resource": ["arn:aws:s3:::acl3/*" ] } ]}',


Expected Output:

    'ResponseMetadata': {
        '...': '...',