# How Amazon Elastic Container Registry works with IAM Before you use IAM to manage access to Amazon ECR, you should understand what IAM features are available to use with Amazon ECR. To get a high-level view of how Amazon ECR and other AWS services work with IAM, see [AWS Services That Work with IAM](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_aws-services-that-work-with-iam.html) in the *IAM User Guide*. **Topics** + [ ## Amazon ECR Identity-based policies ](#security_iam_service-with-iam-id-based-policies) + [ ## Amazon ECR resource-based policies ](#security_iam_service-with-iam-resource-based-policies) + [ ## Authorization based on Amazon ECR tags ](#security_iam_service-with-iam-tags) + [ ## Amazon ECR IAM roles ](#security_iam_service-with-iam-roles) ## Amazon ECR Identity-based policies With IAM identity-based policies, you can specify allowed or denied actions and resources as well as the conditions under which actions are allowed or denied. Amazon ECR supports specific actions, resources, and condition keys. To learn about all of the elements that you use in a JSON policy, see [IAM JSON Policy Elements Reference](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements.html) in the *IAM User Guide*. ### Actions Administrators can use AWS JSON policies to specify who has access to what. That is, which **principal** can perform **actions** on what **resources**, and under what **conditions**. The `Action` element of a JSON policy describes the actions that you can use to allow or deny access in a policy. Include actions in a policy to grant permissions to perform the associated operation. Policy actions in Amazon ECR use the following prefix before the action: `ecr:`. For example, to grant someone permission to create an Amazon ECR repository with the Amazon ECR `CreateRepository` API operation, you include the `ecr:CreateRepository` action in their policy. Policy statements must include either an `Action` or `NotAction` element. Amazon ECR defines its own set of actions that describe tasks that you can perform with this service. To specify multiple actions in a single statement, separate them with commas as follows: ``` "Action": [ "ecr:action1", "ecr:action2" ``` You can specify multiple actions using wildcards (\$1). For example, to specify all actions that begin with the word `Describe`, include the following action: ``` "Action": "ecr:Describe*" ``` To see a list of Amazon ECR actions, see [Actions, Resources, and Condition Keys for Amazon Elastic Container Registry](https://docs.aws.amazon.com/IAM/latest/UserGuide/list_amazonelasticcontainerregistry.html) in the *IAM User Guide*. ### Resources Administrators can use AWS JSON policies to specify who has access to what. That is, which **principal** can perform **actions** on what **resources**, and under what **conditions**. The `Resource` JSON policy element specifies the object or objects to which the action applies. As a best practice, specify a resource using its [Amazon Resource Name (ARN)](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference-arns.html). For actions that don't support resource-level permissions, use a wildcard (\$1) to indicate that the statement applies to all resources. ``` "Resource": "*" ``` An Amazon ECR repository resource has the following ARN: ``` arn:${Partition}:ecr:${Region}:${Account}:repository/${Repository-name} ``` For more information about the format of ARNs, see [Amazon Resource Names (ARNs) and AWS Service Namespaces](https://docs.aws.amazon.com/general/latest/gr/aws-arns-and-namespaces.html). For example, to specify the `my-repo` repository in the `us-east-1` Region in your statement, use the following ARN: ``` "Resource": "arn:aws:ecr:us-east-1:123456789012:repository/my-repo" ``` To specify all repositories that belong to a specific account, use the wildcard (\$1): ``` "Resource": "arn:aws:ecr:us-east-1:123456789012:repository/*" ``` To specify multiple resources in a single statement, separate the ARNs with commas. ``` "Resource": [ "resource1", "resource2" ``` To see a list of Amazon ECR resource types and their ARNs, see [Resources Defined by Amazon Elastic Container Registry](https://docs.aws.amazon.com/IAM/latest/UserGuide/list_amazonelasticcontainerregistry.html#amazonelasticcontainerregistry-resources-for-iam-policies) in the *IAM User Guide*. To learn with which actions you can specify the ARN of each resource, see [Actions Defined by Amazon Elastic Container Registry](https://docs.aws.amazon.com/IAM/latest/UserGuide/list_amazonelasticcontainerregistry.html#amazonelasticcontainerregistry-actions-as-permissions). ### Condition keys Administrators can use AWS JSON policies to specify who has access to what. That is, which **principal** can perform **actions** on what **resources**, and under what **conditions**. The `Condition` element specifies when statements execute based on defined criteria. You can create conditional expressions that use [condition operators](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_condition_operators.html), such as equals or less than, to match the condition in the policy with values in the request. To see all AWS global condition keys, see [AWS global condition context keys](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_condition-keys.html) in the *IAM User Guide*. Amazon ECR defines its own set of condition keys and also supports using some global condition keys. To see all AWS global condition keys, see [AWS Global Condition Context Keys](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_condition-keys.html) in the *IAM User Guide*. Most Amazon ECR actions support the `aws:ResourceTag` and `ecr:ResourceTag` condition keys. For more information, see [Using Tag-Based Access Control](ecr-supported-iam-actions-tagging.md). To see a list of Amazon ECR condition keys, see [Condition Keys Defined by Amazon Elastic Container Registry](https://docs.aws.amazon.com/IAM/latest/UserGuide/list_amazonelasticcontainerregistry.html#amazonelasticcontainerregistry-policy-keys) in the *IAM User Guide*. To learn with which actions and resources you can use a condition key, see [Actions Defined by Amazon Elastic Container Registry](https://docs.aws.amazon.com/IAM/latest/UserGuide/list_amazonelasticcontainerregistry.html#amazonelasticcontainerregistry-actions-as-permissions). ### Examples To view examples of Amazon ECR identity-based policies, see [Amazon Elastic Container Registry Identity-based policy examples](security_iam_id-based-policy-examples.md). ## Amazon ECR resource-based policies Resource-based policies are JSON policy documents that specify what actions a specified principal can perform on an Amazon ECR resource and under what conditions. Amazon ECR supports resource-based permissions policies for Amazon ECR repositories. Resource-based policies let you grant usage permission to other accounts on a per-resource basis. You can also use a resource-based policy to allow an AWS service to access your Amazon ECR repositories. To enable cross-account access, you can specify an entire account or IAM entities in another account as the [principal in a resource-based policy](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_principal.html). Adding a cross-account principal to a resource-based policy is only half of establishing the trust relationship. When the principal and the resource are in different AWS accounts, you must also grant the principal entity permission to access the resource. Grant permission by attaching an identity-based policy to the entity. However, if a resource-based policy grants access to a principal in the same account, you don't need additional Amazon ECR repository permissions in the identity-based policy. For more information, see [How IAM Roles Differ from Resource-based Policies ](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_compare-resource-policies.html)in the *IAM User Guide*. The Amazon ECR service supports only one type of resource-based policy called a *repository policy*, which is attached to a *repository*. This policy defines which principal entities (accounts, users, roles, and federated users) can perform actions on the repository. To learn how to attach a resource-based policy to a repository, see [Private repository policies in Amazon ECR](repository-policies.md). **Note** In an Amazon ECR repository policy, the policy element `Sid` supports additional characters and spacing not supported in IAM policies. ### Examples To view examples of Amazon ECR resource-based policies, see [Private repository policy examples in Amazon ECR](repository-policy-examples.md), ## Authorization based on Amazon ECR tags You can attach tags to Amazon ECR resources or pass tags in a request to Amazon ECR. To control access based on tags, you provide tag information in the [condition element](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_condition.html) of a policy using the `ecr:ResourceTag/key-name`, `aws:RequestTag/key-name`, or `aws:TagKeys` condition keys. For more information about tagging Amazon ECR resources, see [Tagging a private repository in Amazon ECR](ecr-using-tags.md). To view an example identity-based policy for limiting access to a resource based on the tags on that resource, see [Using Tag-Based Access Control](ecr-supported-iam-actions-tagging.md). ## Amazon ECR IAM roles An [IAM role](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles.html) is an entity within your AWS account that has specific permissions. ### Using Temporary Credentials with Amazon ECR You can use temporary credentials to sign in with federation, assume an IAM role, or to assume a cross-account role. You obtain temporary security credentials by calling AWS STS API operations such as [AssumeRole](https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRole.html) or [GetFederationToken](https://docs.aws.amazon.com/STS/latest/APIReference/API_GetFederationToken.html). Amazon ECR supports using temporary credentials. ### Service-linked roles [Service-linked roles](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_terms-and-concepts.html#iam-term-service-linked-role) allow AWS services to access resources in other services to complete an action on your behalf. Service-linked roles appear in your IAM account and are owned by the service. An IAM administrator can view but not edit the permissions for service-linked roles. Amazon ECR supports service-linked roles. For more information, see [Using service-linked roles for Amazon ECR](using-service-linked-roles.md).