AWS::WAF::SizeConstraintSet

Note

This is AWS WAF Classic documentation. For more information, see AWS WAF Classic in the developer guide.

For the latest version of AWS WAF , use the AWS WAFV2 API and see the AWS WAF Developer Guide. With the latest version, AWS WAF has a single set of endpoints for regional and global use.

A complex type that contains SizeConstraint objects, which specify the parts of web requests that you want AWS WAF to inspect the size of. If a SizeConstraintSet contains more than one SizeConstraint object, a request only needs to match one constraint to be considered a match.

Syntax

To declare this entity in your AWS CloudFormation template, use the following syntax:

JSON

{
  "Type" : "AWS::WAF::SizeConstraintSet",
  "Properties" : {
      "Name" : String,
      "SizeConstraints" : [ SizeConstraint, ... ]
    }
}

YAML

Type: AWS::WAF::SizeConstraintSet
Properties: 
  Name: String
  SizeConstraints: 
    - SizeConstraint

Properties

Name

The name, if any, of the SizeConstraintSet.

Required: Yes

Type: String

Minimum: 1

Maximum: 128

Pattern: .*\S.*

Update requires: Replacement

SizeConstraints

The size constraint and the part of the web request to check.

Required: Yes

Type: List of SizeConstraint

Update requires: No interruption

Return values

Ref

When you pass the logical ID of this resource to the intrinsic Ref function, Ref returns the resource physical ID, such as 1234a1a-a1b1-12a1-abcd-a123b123456.

For more information about using the Ref function, see Ref.

Examples

Define a Size Constraint

The following example checks that the body of an HTTP request equals 4096 bytes.

JSON

"MySizeConstraint": {
  "Type": "AWS::WAF::SizeConstraintSet",
  "Properties": {
    "Name": "SizeConstraints",
    "SizeConstraints": [
      {
        "ComparisonOperator": "EQ",
        "FieldToMatch": {
          "Type": "BODY"
        },
        "Size": "4096",
        "TextTransformation": "NONE"
      }
    ]
  }
}

YAML

  MySizeConstraint: 
    Type: "AWS::WAF::SizeConstraintSet"
    Properties: 
      Name: "SizeConstraints"
      SizeConstraints: 
        - 
          ComparisonOperator: "EQ"
          FieldToMatch: 
            Type: "BODY"
          Size: "4096"
          TextTransformation: "NONE"

Associate a SizeConstraintSet with a Web ACL Rule

The following example associates the MySizeConstraint object with a web ACL rule.

JSON

"SizeConstraintRule" : {
  "Type": "AWS::WAF::Rule",
  "Properties": {
    "Name": "SizeConstraintRule",
    "MetricName" : "SizeConstraintRule",
    "Predicates": [
      {
        "DataId" : {  "Ref" : "MySizeConstraint" },
        "Negated" : false,
        "Type" : "SizeConstraint"
      }
    ]
  }
}

YAML

SizeConstraintRule: 
  Type: "AWS::WAF::Rule"
  Properties: 
    Name: "SizeConstraintRule"
    MetricName: "SizeConstraintRule"
    Predicates: 
      - 
        DataId: 
          Ref: "MySizeConstraint"
        Negated: false
        Type: "SizeConstraint"

Create a Web ACL

The following example associates the SizeConstraintRule rule with a web ACL. The web ACL blocks all requests except for requests with a body size equal to 4096 bytes.

JSON

"MyWebACL": {
  "Type": "AWS::WAF::WebACL",
  "Properties": {
    "Name": "Web ACL to allow requests with a specific size",
    "DefaultAction": {
      "Type": "BLOCK"
    },
    "MetricName" : "SizeConstraintWebACL",
    "Rules": [
      {
        "Action" : {
          "Type" : "ALLOW"
        },
        "Priority" : 1,
        "RuleId" : { "Ref" : "SizeConstraintRule" }
      }
    ]
  }
}

YAML

MyWebACL: 
  Type: "AWS::WAF::WebACL"
  Properties: 
    Name: "Web ACL to allow requests with a specific size"
    DefaultAction: 
      Type: "BLOCK"
    MetricName: "SizeConstraintWebACL"
    Rules: 
      - 
        Action: 
          Type: "ALLOW"
        Priority: 1
        RuleId: 
         Ref: "SizeConstraintRule"