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IAM JSON policy elements: Condition operators

Use condition operators in the Condition element to match the condition key and value in the policy against values in the request context. For more information about the Condition element, see IAM JSON policy elements: Condition.

The condition operator that you can use in a policy depends on the condition key you choose. You can choose a global condition key or a service-specific condition key. To learn which condition operator you can use for a global condition key, see Amazon global condition context keys. To learn which condition operator you can use for a service-specific condition key, see Actions, Resources, and Condition Keys for Amazon Services and choose the service that you want to view.

The condition operators can be grouped into the following categories:

String condition operators

String condition operators let you construct Condition elements that restrict access based on comparing a key to a string value.

For example, the following statement contains a Condition element that uses aws:PrincipalTag key to specify that the principal making the request must be tagged with the iamuser-admin job category.

{
  "Version": "2012-10-17",
  "Statement": {
    "Effect": "Allow",
    "Action": "iam:*AccessKey*",
    "Resource": "arn:aws-cn:iam::account-id:user/*",
    "Condition": {"StringEquals": {"aws:PrincipalTag/job-category": "iamuser-admin"}}
  }
}

If the key that you specify in a policy condition is not present in the request context, the values do not match. In this example, the aws:PrincipalTag/job-category key is present in the request context if the principal is using an IAM user with attached tags. It is also included for a principal using an IAM role with attached tags or session tags. If a user without the tag attempts to view or edit an access key, the condition returns false and the request is implicitly denied by this statement.

You can use a policy variable with the String condition operator.

The following example uses the StringLike condition operator to perform string matching with a policy variable to create a policy that lets an IAM user use the Amazon S3 console to manage his or her own "home directory" in an Amazon S3 bucket. The policy allows the specified actions on an S3 bucket as long as the s3:prefix matches any one of the specified patterns.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "s3:ListAllMyBuckets",
        "s3:GetBucketLocation"
      ],
      "Resource": "arn:aws-cn:s3:::*"
    },
    {
      "Effect": "Allow",
      "Action": "s3:ListBucket",
      "Resource": "arn:aws-cn:s3:::BUCKET-NAME",
      "Condition": {"StringLike": {"s3:prefix": [
        "",
        "home/",
        "home/${aws:username}/"
      ]}}
    },
    {
      "Effect": "Allow",
      "Action": "s3:*",
      "Resource": [
        "arn:aws-cn:s3:::BUCKET-NAME/home/${aws:username}",
        "arn:aws-cn:s3:::BUCKET-NAME/home/${aws:username}/*"
      ]
    }
  ]
}

For an example of a policy that shows how to use the Condition element to restrict access to resources based on an application ID and a user ID for OIDC federation, see Amazon S3: Allows Amazon Cognito users to access objects in their bucket.

Wildcard matching

String condition operators perform a patternless matching that does not enforce a predefined format. ARN and Date condition operators are a subset of string operators that enforce a structure on the condition key value. When you use StringLike or StringNotLike operators for partial string matches of an ARN or date, the matching ignores which portion of the structure is wildcarded.

For example, the following conditions search for a partial match of an ARN using different condition operators.

When ArnLike is used, the partition, service, account-id, resource-type, and partial resource-id portions of the ARN must have exact matching to the ARN in the request context. Only the region and resource path allow partial matching.

"Condition": {"ArnLike": {"aws:SourceArn": "arn:aws:cloudtrail:*:111122223333:trail/*"}}

When StringLike is used instead of ArnLike, matching ignores the ARN structure and allows partial matching, regardless of the portion that was wildcarded.

"Condition": {"StringLike": {"aws:SourceArn": "arn:aws:cloudtrail:*:111122223333:trail/*"}}

Numeric condition operators

Numeric condition operators let you construct Condition elements that restrict access based on comparing a key to an integer or decimal value.

For example, the following statement contains a Condition element that uses the NumericLessThanEquals condition operator with the s3:max-keys key to specify that the requester can list up to 10 objects in example_bucket at a time.

{
  "Version": "2012-10-17",
  "Statement": {
    "Effect": "Allow",
    "Action": "s3:ListBucket",
    "Resource": "arn:aws-cn:s3:::example_bucket",
    "Condition": {"NumericLessThanEquals": {"s3:max-keys": "10"}}
  }
}

If the key that you specify in a policy condition is not present in the request context, the values do not match. In this example, the s3:max-keys key is always present in the request when you perform the ListBucket operation. If this policy allowed all Amazon S3 operations, then only the operations that include the max-keys context key with a value of less than or equal to 10 would be allowed.

You can not use a policy variable with the Numeric condition operator.

Date condition operators

Date condition operators let you construct Condition elements that restrict access based on comparing a key to a date/time value. You use these condition operators with aws:CurrentTime key or aws:EpochTime key. You must specify date/time values with one of the W3C implementations of the ISO 8601 date formats or in epoch (UNIX) time.

For example, the following statement contains a Condition element that uses the DateGreaterThan condition operator with the aws:TokenIssueTime key. This condition specifies that the temporary security credentials used to make the request were issued in 2020. This policy can be updated programmatically every day to ensure that account members use fresh credentials.

{
  "Version": "2012-10-17",
  "Statement": {
    "Effect": "Allow",
    "Action": "iam:*AccessKey*",
    "Resource": "arn:aws-cn:iam::account-id:user/*",
    "Condition": {"DateGreaterThan": {"aws:TokenIssueTime": "2020-01-01T00:00:01Z"}}
  }
}

If the key that you specify in a policy condition is not present in the request context, the values do not match. The aws:TokenIssueTime key is present in the request context only when the principal uses temporary credentials to make the request. The key is not present in Amazon CLI, Amazon API, or Amazon SDK requests that are made using access keys. In this example, if an IAM user attempts to view or edit an access key, the request is denied.

You can not use a policy variable with the Date condition operator.

Boolean condition operators

Boolean conditions let you construct Condition elements that restrict access based on comparing a key to "true" or "false."

For example, this identity-based policy uses the Bool condition operator with the aws:SecureTransport key to denies replicating objects and object tags to the destination bucket and its contents if the request is not over SSL.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "BooleanExample",
      "Action": "s3:ReplicateObject",
      "Effect": "Deny",
      "Resource": [
        "arn:aws-cn:s3:::DOC-EXAMPLE-BUCKET",
        "arn:aws-cn:s3:::DOC-EXAMPLE-BUCKET/*"
      ],
      "Condition": {
        "Bool": {
          "aws:SecureTransport": "false"
        }
      }
    }
  ]
}

If the key that you specify in a policy condition is not present in the request context, the values do not match. The aws:SecureTransport request context returns true or false.

You can use a policy variable with the Boolean condition operator.

Binary condition operators

The BinaryEquals condition operator let you construct Condition elements that test key values that are in binary format. It compares the value of the specified key byte for byte against a base-64 encoded representation of the binary value in the policy.

"Condition" : {
  "BinaryEquals": {
    "key" : "QmluYXJ5VmFsdWVJbkJhc2U2NA=="
  }
}     

If the key that you specify in a policy condition is not present in the request context, the values do not match.

You can not use a policy variable with the Binary condition operator.

IP address condition operators

IP address condition operators let you construct Condition elements that restrict access based on comparing a key to an IPv4 or IPv6 address or range of IP addresses. You use these with the aws:SourceIp key. The value must be in the standard CIDR format (for example, 203.0.113.0/24 or 2001:DB8:1234:5678::/64). If you specify an IP address without the associated routing prefix, IAM uses the default prefix value of /32.

Some Amazon services support IPv6, using :: to represent a range of 0s. To learn whether a service supports IPv6, see the documentation for that service.

For example, the following statement uses the IpAddress condition operator with the aws:SourceIp key to specify that the request must come from the IP range 203.0.113.0 to 203.0.113.255.

{
  "Version": "2012-10-17",
  "Statement": {
    "Effect": "Allow",
    "Action": "iam:*AccessKey*",
    "Resource": "arn:aws-cn:iam::account-id:user/*",
    "Condition": {"IpAddress": {"aws:SourceIp": "203.0.113.0/24"}}
  }
}

The aws:SourceIp condition key resolves to the IP address that the request originates from. If the requests originates from an Amazon EC2 instance, aws:SourceIp evaluates to the instance's public IP address.

If the key that you specify in a policy condition is not present in the request context, the values do not match. The aws:SourceIp key is always present in the request context, except when the requester uses a VPC endpoint to make the request. In this case, the condition returns false and the request is implicitly denied by this statement.

You can not use a policy variable with the IpAddress condition operator.

The following example shows how to mix IPv4 and IPv6 addresses to cover all of your organization's valid IP addresses. We recommend that you update your organization's policies with your IPv6 address ranges in addition to IPv4 ranges you already have to ensure the policies continue to work as you make the transition to IPv6.

{
  "Version": "2012-10-17",
  "Statement": {
    "Effect": "Allow",
    "Action": "someservice:*",
    "Resource": "*",
    "Condition": {
      "IpAddress": {
        "aws:SourceIp": [
          "203.0.113.0/24",
          "2001:DB8:1234:5678::/64"
        ]
      }
    }
  }
}

The aws:SourceIp condition key works only in a JSON policy if you are calling the tested API directly as a user. If you instead use a service to call the target service on your behalf, the target service sees the IP address of the calling service rather than the IP address of the originating user. This can happen, for example, if you use Amazon CloudFormation to call Amazon EC2 to construct instances for you. There is currently no way to pass the originating IP address through a calling service to the target service for evaluation in a JSON policy. For these types of service API calls, do not use the aws:SourceIp condition key.

Amazon Resource Name (ARN) condition operators

Amazon Resource Name (ARN) condition operators let you construct Condition elements that restrict access based on comparing a key to an ARN. The ARN is considered a string.

You can use a policy variable with the ARN condition operator.

The following resource-based policy example shows a policy attached to an Amazon SQS queue to which you want to send SNS messages. It gives Amazon SNS permission to send messages to the queue (or queues) of your choice, but only if the service is sending the messages on behalf of a particular Amazon SNS topic (or topics). You specify the queue in the Resource field, and the Amazon SNS topic as the value for the SourceArn key.

{
  "Version": "2012-10-17",
  "Statement": {
    "Effect": "Allow",
    "Principal": {"AWS": "123456789012"},
    "Action": "SQS:SendMessage",
    "Resource": "arn:aws-cn:sqs:REGION:123456789012:QUEUE-ID",
    "Condition": {"ArnEquals": {"aws:SourceArn": "arn:aws-cn:sns:REGION:123456789012:TOPIC-ID"}}
  }
}

If the key that you specify in a policy condition is not present in the request context, the values do not match. The aws:SourceArn key is present in the request context only if a resource triggers a service to call another service on behalf of the resource owner. If an IAM user attempts to perform this operation directly, the condition returns false and the request is implicitly denied by this statement.

...IfExists condition operators

You can add IfExists to the end of any condition operator name except the Null condition—for example, StringLikeIfExists. You do this to say "If the policy key is present in the context of the request, process the key as specified in the policy. If the key is not present, evaluate the condition element as true." Other condition elements in the statement can still result in a nonmatch, but not a missing key when checked with ...IfExists. If you are using an "Effect": "Deny" element with a negated condition operator like StringNotEqualsIfExists, the request is still denied even if the tag is missing.

Example using IfExists

Many condition keys describe information about a certain type of resource and only exist when accessing that type of resource. These condition keys are not present on other types of resources. This doesn't cause an issue when the policy statement applies to only one type of resource. However, there are cases where a single statement can apply to multiple types of resources, such as when the policy statement references actions from multiple services or when a given action within a service accesses several different resource types within the same service. In such cases, including a condition key that applies to only one of the resources in the policy statement can cause the Condition element in the policy statement to fail such that the statement's "Effect" does not apply.

For example, consider the following policy example:

{
  "Version": "2012-10-17",
  "Statement": {
    "Sid": "THISPOLICYDOESNOTWORK",
    "Effect": "Allow",
    "Action": "ec2:RunInstances",
    "Resource": "*",
    "Condition": {"StringLike": {"ec2:InstanceType": [
      "t1.*",
      "t2.*",
      "m3.*"
    ]}}
  }
}

The intent of the preceding policy is to enable the user to launch any instance that is type t1, t2 or m3. However, launching an instance requires accessing many resources in addition to the instance itself; for example, images, key pairs, security groups, and more. The entire statement is evaluated against every resource that is required to launch the instance. These additional resources do not have the ec2:InstanceType condition key, so the StringLike check fails, and the user is not granted the ability to launch any instance type.

To address this, use the StringLikeIfExists condition operator instead. This way, the test only happens if the condition key exists. You could read the following policy as: "If the resource being checked has an "ec2:InstanceType" condition key, then allow the action only if the key value begins with t1., t2., or m3.. If the resource being checked does not have that condition key, then don't worry about it." The asterisk (*) in the condition key values, when used with the StringLikeIfExists condition operator, is interpreted as a wildcard to achieve partial string matches. The DescribeActions statement includes the actions required to view the instance in the console.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "RunInstance",
            "Effect": "Allow",
            "Action": "ec2:RunInstances",
            "Resource": "*",
            "Condition": {
                "StringLikeIfExists": {
                    "ec2:InstanceType": [
                        "t1.*",
                        "t2.*",
                        "m3.*"
             ]}}
        },
        {
            "Sid": "DescribeActions",
            "Effect": "Allow",
            "Action": [
                "ec2:DescribeImages",
                "ec2:DescribeInstances",
                "ec2:DescribeVpcs",
                "ec2:DescribeKeyPairs",
                "ec2:DescribeSubnets",
                "ec2:DescribeSecurityGroups"
            ],
            "Resource": "*"
        }]
}

Condition operator to check existence of condition keys

Use a Null condition operator to check if a condition key is absent at the time of authorization. In the policy statement, use either true (the key doesn't exist — it is null) or false (the key exists and its value is not null).

You can not use a policy variable with the Null condition operator.

For example, you can use this condition operator to determine whether a user is using their own credentials for the operation or temporary credentials. If the user is using temporary credentials, then the key aws:TokenIssueTime exists and has a value. The following example shows a condition that states that the user must not be using temporary credentials (the key must not exist) for the user to use the Amazon EC2 API.

{
  "Version": "2012-10-17",
  "Statement":{
      "Action":"ec2:*",
      "Effect":"Allow",
      "Resource":"*",
      "Condition":{"Null":{"aws:TokenIssueTime":"true"}}
  }
}