IAM JSON policy elements: Resource

The Resource element specifies the object or objects that the statement covers. Statements must include either a Resource or a NotResource element. You specify a resource using an ARN. For more information about the format of ARNs, see IAM ARNs.

Each service has its own set of resources. Although you always use an ARN to specify a resource, the details of the ARN for a resource depend on the service and the resource. For information about how to specify a resource, refer to the documentation for the service whose resources you're writing a statement for.

Note

Some services do not let you specify actions for individual resources; instead, any actions that you list in the Action or NotAction element apply to all resources in that service. In these cases, you use the wildcard * in the Resource element.

The following example refers to a specific Amazon SQS queue.

"Resource": "arn:aws:sqs:us-east-2:account-ID-without-hyphens:queue1"

The following example refers to the IAM user named Bob in an AWS account.

"Resource": "arn:aws:iam::account-ID-without-hyphens:user/Bob"

Using wildcards in resource ARNs

You can use wildcards as part of the resource ARN. You can use wildcard characters (* and ?) within any ARN segment (the parts separated by colons). An asterisk (*) represents any combination of characters and a question mark (?) represents any single character. You can use multiple * or ? characters in each segment. The following example refers to all IAM users whose path is /accounting.

"Resource": "arn:aws:iam::account-ID-without-hyphens:user/accounting/*"

The following example refers to all items within a specific Amazon S3 bucket.

"Resource": "arn:aws:s3:::DOC-EXAMPLE-BUCKET/*"

The asterisk (*) character can expand to replace everything within a segment, including characters like a forward slash (/) that may otherwise appear to be a delimiter within a given service’s namespace. For example, consider the following Amazon S3 ARN (the same wildcard expansion logic applies to all services).

"Resource": "arn:aws:s3:::DOC-EXAMPLE-BUCKET/*/test/*"

The wildcards in the ARN apply to all of the following objects in the bucket, not only the first object listed.

DOC-EXAMPLE-BUCKET/1/test/object.jpg
DOC-EXAMPLE-BUCKET/1/2/test/object.jpg
DOC-EXAMPLE-BUCKET/1/2/test/3/object.jpg 
DOC-EXAMPLE-BUCKET/1/2/3/test/4/object.jpg
DOC-EXAMPLE-BUCKET/1///test///object.jpg
DOC-EXAMPLE-BUCKET/1/test/.jpg
DOC-EXAMPLE-BUCKET//test/object.jpg
DOC-EXAMPLE-BUCKET/1/test/

Consider the last two objects in the previous list. An Amazon S3 object name can validly begin or end with the conventional delimiter forward slash (/) character. While "/" works as a delimiter, there is no specific significance when this character is used within a resource ARN. It is treated the same as any other valid character. The ARN would not match the following objects:

DOC-EXAMPLE-BUCKET/1-test/object.jpg
DOC-EXAMPLE-BUCKET/test/object.jpg
DOC-EXAMPLE-BUCKET/1/2/test.jpg

Specifying multiple resources

You can specify multiple resources. The following example refers to two DynamoDB tables.

"Resource": [
    "arn:aws:dynamodb:us-east-2:account-ID-without-hyphens:table/books_table",
    "arn:aws:dynamodb:us-east-2:account-ID-without-hyphens:table/magazines_table"
]

Using policy variables in resource ARNs

In the Resource element, you can use JSON policy variables in the part of the ARN that identifies the specific resource (that is, in the trailing part of the ARN). For example, you can use the key {aws:username} as part of a resource ARN to indicate that the current user's name should be included as part of the resource's name. The following example shows how you can use the {aws:username} key in a Resource element. The policy allows access to a Amazon DynamoDB table that matches the current user's name.

{
  "Version": "2012-10-17",
  "Statement": {
    "Effect": "Allow",
    "Action": "dynamodb:*",
    "Resource": "arn:aws:dynamodb:us-east-2:ACCOUNT-ID-WITHOUT-HYPHENS:table/${aws:username}"
  }
}

For more information about JSON policy variables, see IAM policy elements: Variables and tags.