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 you want to write a statement.
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-cn:sqs:us-west-2:
account-ID-without-hyphens
:queue1"
The following example refers to the IAM user named Bob in an Amazon Web Services account.
Note
In the Resource
element, the IAM user name is case sensitive.
"Resource": "arn:aws-cn: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 ARN segments (the parts separated by colons) to represent any combination of characters with an asterisk (*) and any single character with a question mark (?). You can use multiple * or ? characters in each segment.
Note
You can't use a wildcard in the service segment that identifies the Amazon product. For more information about ARN segments, see Amazon Resource Names (ARNs)
The following example refers to all IAM users whose path is /accounting
.
"Resource": "arn:aws-cn:iam::
account-ID-without-hyphens
:user/accounting/*"
The following example refers to all items within a specific Amazon S3 bucket.
"Resource": "arn:aws-cn: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 namespace. For example, consider the following Amazon S3 ARN as the same wildcard expansion logic applies to all services.
"Resource": "arn:aws-cn: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.jpgDOC-EXAMPLE-BUCKET
/1/2/test/object.jpgDOC-EXAMPLE-BUCKET
/1/2/test/3/object.jpgDOC-EXAMPLE-BUCKET
/1/2/3/test/4/object.jpgDOC-EXAMPLE-BUCKET
/1///test///object.jpgDOC-EXAMPLE-BUCKET
/1/test/.jpgDOC-EXAMPLE-BUCKET
//test/object.jpgDOC-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.jpgDOC-EXAMPLE-BUCKET
/test/object.jpgDOC-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-cn:dynamodb:us-west-2:
account-ID-without-hyphens
:table/books_table", "arn:aws-cn:dynamodb:us-west-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-cn:dynamodb:us-west-2:
account-id
:table/${aws:username}" } }
For more information about JSON policy variables, see IAM policy elements: Variables and tags.