允許CloudFront使用原始訪問身份訪問S3存儲桶

Question

我已經做了一個靜態網站，托管由CloudFront服務的S3存儲桶。 我想僅通過原始訪問身份限制從CloudFront直接進行存儲桶訪問。

我嘗試更新S3存儲桶策略，但顯示錯誤：

Error putting S3 policy: MalformedPolicy: Invalid principal in policy status code: 400, request id

我正在嘗試使用以下政策：

resource "aws_s3_bucket_policy" "default" {
  bucket = "${aws_s3_bucket.default.id}"
  policy = <<EOF
  {
"Version": "2008-10-17",
"Statement": [
    {
        "Sid": "2",
        "Effect": "Allow",
        "Principal": {
            "AWS": "arn:aws:iam::cloudfront:user/CloudFront Origin Access Identity ${aws_cloudfront_origin_access_identity.origin_access_identity.id}"
        },
        "Action": "s3:*",
        "Resource": "arn:aws:s3:::$/*"
    }
  ]
}
EOF 
}

Answer 1

如aws_cloudfront_origin_access_identity文檔中所述，最好的方法是通過使用aws_iam_policy_document數據源生成IAM策略文檔，然后將其直接附加。

一個例子看起來像這樣：

data "aws_iam_policy_document" "s3_policy" {
  statement {
    actions   = ["s3:GetObject"]
    resources = ["${module.names.s3_endpoint_arn_base}/*"]

    principals {
      type        = "AWS"
      identifiers = ["${aws_cloudfront_origin_access_identity.origin_access_identity.iam_arn}"]
    }
  }

  statement {
    actions   = ["s3:ListBucket"]
    resources = ["${module.names.s3_endpoint_arn_base}"]

    principals {
      type        = "AWS"
      identifiers = ["${aws_cloudfront_origin_access_identity.origin_access_identity.iam_arn}"]
    }
  }
}

resource "aws_s3_bucket" "bucket" {
  # ...
  policy = "${data.aws_iam_policy_document.s3_policy.json}"
}

如果您真的想像問題中那樣手工制定IAM策略，那么您只需要以下內容：

resource "aws_s3_bucket_policy" "default" {
  bucket = "${aws_s3_bucket.default.id}"
  policy = <<EOF
{
"Version": "2008-10-17",
"Statement": [
    {
        "Sid": "2",
        "Effect": "Allow",
        "Principal": {
            "AWS": "${aws_cloudfront_origin_access_identity.origin_access_identity.id}"
        },
        "Action": "s3:*",
        "Resource": "${aws_s3_bucket.default.arn}""
    }
  ]
}
EOF 
}