AWS S3 IAM user policy setup for bucket

First of all, setup your AWS account – and login into AWS Management Console. Then create any bucket you want.

Next step is to add new IAM user – go to https://console.aws.amazon.com/iam/home?#users, select Users and click Create new user button.

iam_create

Click Create and copy/paste or download your access keys.

iam_access

Then close window and click to summary tab – you’ll need to copy ARN notation of this user

iam_summary

 

s3cmd

To be able to sync some folders and/or use s3cmd commandline tool, you need to setup some more policies. Click Permission tab and then Attach User Policy. Then choose Policy Generator and follow these steps:

manage_user_policySet permissions as shown in following image – we need ListAllMyBuckets for :::* and ListBucket and PutObject for the one, specified bucket.

user_policy_editor

 

Click Continue and save new policy

set_permission

You can always edit the policy using Manage Policy. You should create this kind of policy file:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "Stmt1402603222000",
      "Effect": "Allow",
      "Action": [
        "s3:ListAllMyBuckets"
      ],
      "Resource": [
        "arn:aws:s3:::*"
      ]
    },
    {
      "Sid": "Stmt1402603306000",
      "Effect": "Allow",
      "Action": [
        "s3:ListBucket",
        "s3:PutObject"
      ],
      "Resource": [
        "arn:aws:s3:::sample_bucket/*"
      ]
    }
  ]
}

That’s all. Lets move to bucket policy.

Bucket policy

Now you can open Policy Generator – http://awspolicygen.s3.amazonaws.com/policygen.html and start adding new items.

First of all, select your policy type – S3

policy_select_type

and then fill new policy – we need two policies – one for all users to read objects (GetObject) and second for your new user, to be able to upload, delete and get object as well.

public_policy_form

and click Add Statement. The list below the form should look like

public_policy_list

So, add your user the same way. As principal add your ARN notation (which you copied before) and add Actions as shown below.

policy_user

All set. You need to click Generate Policy button and copy freshly generated JSON policy to your clipboard

{
  "Id": "Policy1402594421281",
  "Statement": [
    {
      "Sid": "Stmt1402593998750",
      "Action": [
        "s3:GetObject"
      ],
      "Effect": "Allow",
      "Resource": "arn:aws:s3:::sample_bucket/*",
      "Principal": {
        "AWS": [
          "*"
        ]
      }
    },
    {
      "Sid": "Stmt1402594323930",
      "Action": [
        "s3:AbortMultipartUpload",
        "s3:DeleteObject",
        "s3:GetObject",
        "s3:GetObjectAcl",
        "s3:PutObject",
        "s3:PutObjectAcl"
      ],
      "Effect": "Allow",
      "Resource": "arn:aws:s3:::sample_bucket/*",
      "Principal": {
        "AWS": [
          "arn:aws:iam::024698735884:user/sample_user"
        ]
      }
    }
  ]
}

Last step is to add this policy to the bucket. Go back to your S3 console (https://console.aws.amazon.com/s3/home), click loupe icon next to bucket name and open Permission section. Click on Edit Bucket Policy and paste the generated policy into that window. Save and you’re done.

bucket_permission

 

You’ll need API keys for use with Paperclip or any other S3 storage engine, so keep them safe.

PS: when you plan to use s3 as storage for your static files, avoid using underscore in your bucket name – as it does not comply with valid FQDN. ‘sample_bucket’ was used only as an example, in the real word you should use ‘sample-bucket’.

Leave a Reply

Your email address will not be published. Required fields are marked *

− 4 = 2