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SFTP 伺服器上的 AWS Transfer 權限被拒絕

tag-icon • tag-icon ftp sftp amazon-web-services
SFTP 伺服器上的 AWS Transfer 權限被拒絕

我可以使用 cyberduck 或 filezilla 登入我的伺服器，但無法讀取我的主目錄。 s3 儲存桶"mybucket"存在。在網路鴨子中我看到

"Cannot readdir on root. Please contact your web hosting service provider for assistance." and in Filezilla "Error: Reading directory .: permission denied"

即使我可以連接到伺服器。

我是否缺少一些策略中的使用者權限以下 ？

這些是我的權限

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "VisualEditor0",
            "Effect": "Allow",
            "Action": [
                "s3:ListBucket",
                "s3:GetBucketLocation"
            ],
            "Resource": "arn:aws:s3:::MYBUCKET"
        },
        {
            "Sid": "VisualEditor1",
            "Effect": "Allow",
            "Action": [
                "s3:PutObject",
                "s3:GetObject",
                "s3:DeleteObject"
            ],
            "Resource": "arn:aws:s3:::MYBUCKET/*"
        },
        {
            "Sid": "VisualEditor2",
            "Effect": "Allow",
            "Action": "transfer:*",
            "Resource": "*"
        }
    ]
}

這些是我的信任關係:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Principal": {
                "Service": "s3.amazonaws.com"
            },
            "Action": "sts:AssumeRole"
        },
        {
            "Effect": "Allow",
            "Principal": {
                "Service": "transfer.amazonaws.com"
            },
            "Action": "sts:AssumeRole"
        }
    ]
}

答案1

使用者角色應該是：

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AllowListingOfUserFolder",
            "Action": [
                "s3:ListBucket",
                "s3:GetBucketLocation"
            ],
            "Effect": "Allow",
            "Resource": [
                "arn:aws:s3:::BUCKET_NAME"
            ]
        },
        {
            "Sid": "HomeDirObjectAccess",
            "Effect": "Allow",
            "Action": [
                "s3:PutObject",
                "s3:GetObject",
                "s3:DeleteObjectVersion",
                "s3:DeleteObject",
                "s3:GetObjectVersion"
            ],
            "Resource": "arn:aws:s3:::BUCKET_NAME/*"
        }
    ]
}

使用者信任關係：

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "",
      "Effect": "Allow",
      "Principal": {
        "Service": "transfer.amazonaws.com"
      },
      "Action": "sts:AssumeRole"
    }
  ]
}

您的使用者的主目錄應為 /BUCKET_NAME

答案2

我對此有疑問，直到我特別添加了s3:GetObject對該aws_transfer_user策略的許可。我以為s3:ListBucket已經足夠了，但事實並非如此。sftp> ls在我擁有 GetObject 之前會失敗。

這是它的 Terraform：

resource "aws_transfer_user" "example-ftp-user" {
  count                     = length(var.uploader_users)
  user_name                 = var.uploader_users[count.index].username

  server_id                 = aws_transfer_server.example-transfer.id
  role                      = aws_iam_role.sftp_content_incoming.arn
  home_directory_type       = "LOGICAL"

  home_directory_mappings {
      entry = "/"
      target = "/my-bucket/$${Transfer:UserName}"
    }

    policy = <<POLICY
{
    "Version": "2012-10-17",
    "Statement": [
      {
        "Sid": "AllowSftpUserAccessToS3",
        "Effect": "Allow",
        "Action": [
          "s3:ListBucket",
          "s3:PutObject",
          "s3:GetObject",
          "s3:DeleteObjectVersion",
          "s3:DeleteObject",
          "s3:GetObjectVersion",
          "s3:GetBucketLocation"
        ],
        "Resource": [
          "${aws_s3_bucket.bucket.arn}/${var.uploader_users[count.index].username}",
          "${aws_s3_bucket.bucket.arn}/${var.uploader_users[count.index].username}/*"
        ]
      }
    ]
}
POLICY
}

我在.tfvars文件中定義使用者；例如：

uploader_users = [
  {
    username = "firstuser"
    public_key = "ssh-rsa ...."
  },
  {
    username = "seconduser"
    public_key = "ssh-rsa ..."
  },
  {
    username = "thirduser"
    public_key = "ssh-rsa ..."
  }
]

我希望這可以幫助別人。在我最終讓這項工作發揮作用之前，我花了很多功夫，而且我不能 100% 確定與其他政策的相互作用最終可能會發揮作用。但應用此後，我可以連接並列出儲存桶內容，而不會收到「權限被拒絕」的訊息。

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