How Amazon Rekognition works with IAM

Before you use IAM to manage access to Amazon Rekognition, you should understand what IAM features are available to use with Amazon Rekognition. To get a high-level view of how Amazon Rekognition and other AWS services work with IAM, see AWS Services That Work with IAM in the IAM User Guide.

Amazon Rekognition 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 Rekognition 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 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. Policy actions usually have the same name as the associated AWS API operation. There are some exceptions, such as permission-only actions that don't have a matching API operation. There are also some operations that require multiple actions in a policy. These additional actions are called dependent actions.

Include actions in a policy to grant permissions to perform the associated operation.

Policy actions in Amazon Rekognition use the following prefix before the action: rekognition:. For example, to grant someone permission to detect objects, scenes, or concepts in an image with the Amazon Rekognition DetectLabels API operation, you include the rekognition:DetectLabels action in their policy. Policy statements must include either an Action or NotAction element. Amazon Rekognition 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": [
      "rekognition:action1",
      "rekognition:action2"

You can specify multiple actions using wildcards (*). For example, to specify all actions that begin with the word Describe, include the following action:

"Action": "rekognition:Describe*"

To see a list of Amazon Rekognition actions, see Actions Defined by Amazon Rekognition 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. Statements must include either a Resource or a NotResource element. As a best practice, specify a resource using its Amazon Resource Name (ARN). You can do this for actions that support a specific resource type, known as resource-level permissions.

For actions that don't support resource-level permissions, such as listing operations, use a wildcard (*) to indicate that the statement applies to all resources.

"Resource": "*"

For more information about the format of ARNs, see Amazon Resource Names (ARNs) and AWS Service Namespaces.

For example, to specify the MyCollection collection in your statement, use the following ARN:

"Resource": "arn:aws:rekognition:us-east-1:123456789012:collection/MyCollection"

To specify all instances that belong to a specific account, use the wildcard (*):

"Resource": "arn:aws:rekognition:us-east-1:123456789012:collection/*"

Some Amazon Rekognition actions, such as those for creating resources, cannot be performed on a specific resource. In those cases, you must use the wildcard (*).

"Resource": "*"

To see a list of Amazon Rekognition resource types and their ARNs, see Resources Defined by Amazon Rekognition in the IAM User Guide. To learn with which actions you can specify the ARN of each resource, see Actions Defined by Amazon Rekognition.

Condition keys

Amazon Rekognition does not provide any service-specific condition keys, but it does support using some global condition keys. To see all AWS global condition keys, see AWS Global Condition Context Keys in the IAM User Guide.

Amazon Rekognition resource-based policies

Amazon Rekognition supports resource-based policies for Custom Labels model copy operations. For more information, see Amazon Rekognition resource-based policy examples.

Other services, such as Amazon S3, also support resource-based permissions policies. For example, you can attach a policy to an S3 bucket to manage access permissions to that bucket.

To access images stored in an Amazon S3 bucket, you must have permission to access object in the S3 bucket. With this permission, Amazon Rekognition can download images from the S3 bucket. The following example policy allows the user to perform the s3:GetObject action on the S3 bucket named Tests3bucket.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "s3:GetObject",
            "Resource": [
                "arn:aws:s3:::Tests3bucket/*"
            ]
        }
    ]
}

To use an S3 bucket with versioning enabled, add the s3:GetObjectVersion action, as shown in the following example.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "s3:GetObject",
                "s3:GetObjectVersion"
            ],
            "Resource": [
                "arn:aws:s3:::Tests3bucket/*"
            ]
        }
    ]

Amazon Rekognition IAM roles

An IAM role is an entity within your AWS account that has specific permissions.

Using temporary credentials with Amazon Rekognition

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 or GetFederationToken.

Amazon Rekognition supports using temporary credentials.

Service-linked roles

Service-linked roles 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 Rekognition doesn't support service-linked roles.

Service roles

This feature allows a service to assume a service role on your behalf. This role allows the service to access resources in other services to complete an action on your behalf. Service roles appear in your IAM account and are owned by the account. This means that an IAM administrator can change the permissions for this role. However, doing so might break the functionality of the service.

Amazon Rekognition supports service roles.

Using a service role may create a security issue where Amazon Rekognition is used to call another service and act on resources it shouldn't have access to. To keep your account secure, you should limit the scope of Amazon Rekognition's access to just the resources you are using. This can be done by attaching a trust policy to your IAM service role. For information on how to do this, see Cross-service confused deputy prevention.

Choosing an IAM role in Amazon Rekognition

When you configure Amazon Rekognition to analyze stored videos, you must choose a role to allow Amazon Rekognition to access Amazon SNS on your behalf. If you have previously created a service role or service-linked role, then Amazon Rekognition provides you with a list of roles to choose from. For more information, see Configuring Amazon Rekognition Video.