This is just my notes on the subject of granting access to a S3 bucket to an AWS IAM User. Figuring it out was much harder than it should have been…

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Principal": {
                "AWS": "arn:aws:iam::NNNNNNNNNNNN:user/NEWUSER"
            },
            "Action": ["s3:*"],
            "Resource": "arn:aws:s3:::NEWBUCKET"
        },
        {
            "Effect": "Allow",
            "Principal": {
                "AWS": "arn:aws:iam::NNNNNNNNNNNN:user/NEWUSER"
            },
            "Action": ["s3:*"],
            "Resource": "arn:aws:s3:::NEWBUCKET/*"
        }
    ]
}

That should grant your user all S3 permissions only on the bucket you are adding the policy to. Remember that if you apply other policies to that buck via AWS’s security manager, this could mess up. Also, remember you can limit things to specific actions by listing them in the Actions field.

The key thing for me was the second statement. My upload would not work until I added the statement with the “/*” on the end of the bucket resource.

Oh, and please double check the new bucket’s security before you are done. Don’t just copy paste from here and think you’re perfectly fine.