# Identity-based policy examples for Amazon Elastic File System
<a name="security_iam_id-based-policy-examples"></a>

By default, users and roles don't have permission to create or modify Amazon EFS resources. To grant users permission to perform actions on the resources that they need, an IAM administrator can create IAM policies.

To learn how to create an IAM identity-based policy by using these example JSON policy documents, see [Create IAM policies (console)](https://docs.amazonaws.cn/IAM/latest/UserGuide/access_policies_create-console.html) in the *IAM User Guide*.

For details about actions and resource types defined by Amazon EFS, including the format of the ARNs for each of the resource types, see [Actions, resources, and condition keys for Amazon Elastic File System](https://docs.amazonaws.cn/service-authorization/latest/reference/list_amazonelasticfilesystem.html) in the *Service Authorization Reference*.

**Topics**
+ [Policy best practices](#security_iam_service-with-iam-policy-best-practices)
+ [Using the Amazon EFS console](#security_iam_id-based-policy-examples-console)
+ [Example: Allow users to view their own permissions](#security_iam_id-based-policy-examples-view-own-permissions)
+ [Example: Enforce the creation of encrypted file systems](#using-iam-to-enforce-encryption-at-rest)
+ [Example: Enforce the creation of unencrypted file systems](#using-iam-to-enforce-unencrypted-file-systems)

## Policy best practices
<a name="security_iam_service-with-iam-policy-best-practices"></a>

Identity-based policies determine whether someone can create, access, or delete Amazon EFS resources in your account. These actions can incur costs for your Amazon Web Services account. When you create or edit identity-based policies, follow these guidelines and recommendations:
+ **Get started with Amazon managed policies and move toward least-privilege permissions** – To get started granting permissions to your users and workloads, use the *Amazon managed policies* that grant permissions for many common use cases. They are available in your Amazon Web Services account. We recommend that you reduce permissions further by defining Amazon customer managed policies that are specific to your use cases. For more information, see [Amazon managed policies](https://docs.amazonaws.cn/IAM/latest/UserGuide/access_policies_managed-vs-inline.html#aws-managed-policies) or [Amazon managed policies for job functions](https://docs.amazonaws.cn/IAM/latest/UserGuide/access_policies_job-functions.html) in the *IAM User Guide*.
+ **Apply least-privilege permissions** – When you set permissions with IAM policies, grant only the permissions required to perform a task. You do this by defining the actions that can be taken on specific resources under specific conditions, also known as *least-privilege permissions*. For more information about using IAM to apply permissions, see [ Policies and permissions in IAM](https://docs.amazonaws.cn/IAM/latest/UserGuide/access_policies.html) in the *IAM User Guide*.
+ **Use conditions in IAM policies to further restrict access** – You can add a condition to your policies to limit access to actions and resources. For example, you can write a policy condition to specify that all requests must be sent using SSL. You can also use conditions to grant access to service actions if they are used through a specific Amazon Web Services service, such as Amazon CloudFormation. For more information, see [ IAM JSON policy elements: Condition](https://docs.amazonaws.cn/IAM/latest/UserGuide/reference_policies_elements_condition.html) in the *IAM User Guide*.
+ **Use IAM Access Analyzer to validate your IAM policies to ensure secure and functional permissions** – IAM Access Analyzer validates new and existing policies so that the policies adhere to the IAM policy language (JSON) and IAM best practices. IAM Access Analyzer provides more than 100 policy checks and actionable recommendations to help you author secure and functional policies. For more information, see [Validate policies with IAM Access Analyzer](https://docs.amazonaws.cn/IAM/latest/UserGuide/access-analyzer-policy-validation.html) in the *IAM User Guide*.
+ **Require multi-factor authentication (MFA)** – If you have a scenario that requires IAM users or a root user in your Amazon Web Services account, turn on MFA for additional security. To require MFA when API operations are called, add MFA conditions to your policies. For more information, see [ Secure API access with MFA](https://docs.amazonaws.cn/IAM/latest/UserGuide/id_credentials_mfa_configure-api-require.html) in the *IAM User Guide*.

For more information about best practices in IAM, see [Security best practices in IAM](https://docs.amazonaws.cn/IAM/latest/UserGuide/best-practices.html) in the *IAM User Guide*.

## Using the Amazon EFS console
<a name="security_iam_id-based-policy-examples-console"></a>

To access the Amazon Elastic File System console, you must have a minimum set of permissions. These permissions must allow you to list and view details about the Amazon EFS resources in your Amazon Web Services account. If you create an identity-based policy that is more restrictive than the minimum required permissions, the console won't function as intended for entities (users or roles) with that policy.

You don't need to allow minimum console permissions for users that are making calls only to the Amazon CLI or the Amazon API. Instead, allow access to only the actions that match the API operation that they're trying to perform.

To ensure that users and roles can still use the Amazon EFS console, also attach the Amazon EFS `AmazonElasticFileSystemReadOnlyAccess` Amazon managed policy to the entities. For more information, see [Adding permissions to a user](https://docs.amazonaws.cn/IAM/latest/UserGuide/id_users_change-permissions.html#users_change_permissions-add-console) in the *IAM User Guide*.

You can see the `AmazonElasticFileSystemReadOnlyAccess` and other Amazon EFS managed service policies in [Amazon managed policies for Amazon EFS](security-iam-awsmanpol.md).

## Example: Allow users to view their own permissions
<a name="security_iam_id-based-policy-examples-view-own-permissions"></a>

This example shows how you might create a policy that allows IAM users to view the inline and managed policies that are attached to their user identity. This policy includes permissions to complete this action on the console or programmatically using the Amazon CLI or Amazon API.

```
{
    "Version": "2012-10-17",		 	 	 
    "Statement": [
        {
            "Sid": "ViewOwnUserInfo",
            "Effect": "Allow",
            "Action": [
                "iam:GetUserPolicy",
                "iam:ListGroupsForUser",
                "iam:ListAttachedUserPolicies",
                "iam:ListUserPolicies",
                "iam:GetUser"
            ],
            "Resource": ["arn:aws-cn:iam::*:user/${aws:username}"]
        },
        {
            "Sid": "NavigateInConsole",
            "Effect": "Allow",
            "Action": [
                "iam:GetGroupPolicy",
                "iam:GetPolicyVersion",
                "iam:GetPolicy",
                "iam:ListAttachedGroupPolicies",
                "iam:ListGroupPolicies",
                "iam:ListPolicyVersions",
                "iam:ListPolicies",
                "iam:ListUsers"
            ],
            "Resource": "*"
        }
    ]
}
```

## Example: Enforce the creation of encrypted file systems
<a name="using-iam-to-enforce-encryption-at-rest"></a>

The following example illustrates an identity-based policy that authorizes principals to create only encrypted file systems.

```
{
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "elasticfilesystem:CreateFileSystem",
            "Condition": {
                "Bool": {
                    "elasticfilesystem:Encrypted": "true"
                }
            },
            "Resource": "*"
        }
    ]
}
```

If this policy is assigned to a user who tries to create an unencrypted file system, the request fails. The user sees a message similar to the following, whether they are using the Amazon Web Services Management Console, the Amazon CLI, or the Amazon API or SDK:

```
User: arn:aws:iam::111122223333:user/{{username}} is not authorized to
      perform: elasticfilesystem:CreateFileSystem on the specified resource.
```

## Example: Enforce the creation of unencrypted file systems
<a name="using-iam-to-enforce-unencrypted-file-systems"></a>

The following example illustrates an identity-based policy that authorizes principals to create only unencrypted file systems.

```
{
      "Statement": [
        {            
            "Effect": "Allow",
            "Action": "elasticfilesystem:CreateFileSystem",
            "Condition": {
                "Bool": {
                    "elasticfilesystem:Encrypted": "false"
                }
            },
            "Resource": "*"
        }
    ]
}
```

If this policy is assigned to a user who tries to create an encrypted file system, the request fails. The user sees a message similar to the following, whether they are using the Amazon Web Services Management Console, the Amazon CLI, or the Amazon API or SDK:

```
User: arn:aws:iam::111122223333:user/{{username}} is not authorized to 
      perform: elasticfilesystem:CreateFileSystem on the specified resource.
```

You can also enforce the creation of encrypted or unencrypted EFS file systems by creating an Amazon Organizations service control policy (SCP). For more information about service control policies in Amazon Organizations, see [Service control policies](https://docs.amazonaws.cn/organizations/latest/userguide/orgs_manage_policies_scps.html#orgs_manage_policies_scp) in the *Amazon Organizations User Guide*.