S3: Make uploaded files public by default

Question

I have a public S3 Bucket, with the public policy set like this

{
    "Version": "2012-10-17",
    "Id": "Policy1563368389080",
    "Statement": [
        {
            "Sid": "Stmt1563368385984",
            "Effect": "Allow",
            "Principal": {
                "AWS": "*"
            },
            "Action": [
                "s3:GetObject",
                "s3:GetObjectVersion"
            ],
            "Resource": [
                "arn:aws:s3:::mybucketname/*",
                "arn:aws:s3:::mybucketname"
            ]
        }
    ]
}

However when i upload a new file it isn't public by default. Is there something wrong with my policy?

Answer 1

The problem is here:

    "Principal": {
        "AWS": "*"
    },

It should be:

    "Principal": "*",

Answer 2

To make it public by default you need to add below code under bucket policy of you respective aws S3 bucket.

{
  "Version":"2012-10-17",
  "Statement":[{
    "Sid":"PublicReadGetObject",
        "Effect":"Allow",
      "Principal": "*",
      "Action":["s3:GetObject"],
      "Resource":["arn:aws:s3:::example-bucket/*"
      ]
    }
  ]
}