bucket-policy.json

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AllowAccountAccess",
            "Effect": "Allow",
            "Principal": {
                "AWS": [
                    "arn:aws:iam::000000000000:root",
                    "arn:aws:iam::999999999999:root"
                ]
            },
            "Action": [
                "s3:GetBucketLocation",
                "s3:GetObject",
                "s3:ListBucket"
            ],
            "Resource": [
                "arn:aws:s3:::yourbucketname/*",
                "arn:aws:s3:::yourbucketname"
            ]
        }
    ]
}