Amazon S3: Allows federated users access to their S3 home directory, programmatically and in the console

This example shows how you might create an identity-based policy that allows federated users to access their own home directory bucket object in S3. The home directory is a bucket that includes a home folder and folders for individual federated users. This policy defines permissions for programmatic and console access. To use this policy, replace the italicized placeholder text in the example policy with your own information. Then, follow the directions in create a policy or edit a policy.

The ${aws:userid} variable in this policy resolves to role-id:specified-name. The role-id part of the federated user ID is a unique identifier assigned to the federated user's role during creation. For more information, see Unique identifiers. The specified-name is the RoleSessionName parameter passed to the AssumeRoleWithWebIdentity request when the federated user assumed their role.

You can view the role ID using the AWS CLI command aws iam get-role --role-name specified-name. For example, imagine that you specify the friendly name John and the CLI returns the role ID AROAXXT2NJT7D3SIQN7Z6. In this case, the federated user ID is AROAXXT2NJT7D3SIQN7Z6:John. This policy then allows the federated user John to access the Amazon S3 bucket with prefix AROAXXT2NJT7D3SIQN7Z6:John.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "S3ConsoleAccess",
            "Effect": "Allow",
            "Action": [
                "s3:GetAccountPublicAccessBlock",
                "s3:GetBucketAcl",
                "s3:GetBucketLocation",
                "s3:GetBucketPolicyStatus",
                "s3:GetBucketPublicAccessBlock",
                "s3:ListAccessPoints",
                "s3:ListAllMyBuckets"
            ],
            "Resource": "*"
        },
        {
            "Sid": "ListObjectsInBucket",
            "Effect": "Allow",
            "Action": "s3:ListBucket",
            "Resource": "arn:aws:s3:::amzn-s3-demo-bucket",
            "Condition": {
                "StringLike": {
                    "s3:prefix": [
                        "",
                        "home/",
                        "home/${aws:userid}/*"
                    ]
                }
            }
        },
        {
            "Effect": "Allow",
            "Action": "s3:*",
            "Resource": [
                "arn:aws:s3:::amzn-s3-demo-bucket/home/${aws:userid}",
                "arn:aws:s3:::amzn-s3-demo-bucket/home/${aws:userid}/*"
            ]
        }
    ]
}