Request Parameters Response Elements Errors Examples See Also

SimulatePrincipalPolicy

Simulate how a set of IAM policies attached to an IAM entity works with a list of API operations and AWS resources to determine the policies' effective permissions. The entity can be an IAM user, group, or role. If you specify a user, then the simulation also includes all of the policies that are attached to groups that the user belongs to. You can simulate resources that don't exist in your account.

You can optionally include a list of one or more additional policies specified as strings to include in the simulation. If you want to simulate only policies specified as strings, use SimulateCustomPolicy instead.

You can also optionally include one resource-based policy to be evaluated with each of the resources included in the simulation for IAM users only.

The simulation does not perform the API operations; it only checks the authorization to determine if the simulated policies allow or deny the operations.

Note: This operation discloses information about the permissions granted to other users. If you do not want users to see other user's permissions, then consider allowing them to use SimulateCustomPolicy instead.

Context keys are variables maintained by AWS and its services that provide details about the context of an API query request. You can use the Condition element of an IAM policy to evaluate context keys. To get the list of context keys that the policies require for correct simulation, use GetContextKeysForPrincipalPolicy.

If the output is long, you can use the MaxItems and Marker parameters to paginate the results.

Note

The IAM policy simulator evaluates statements in the identity-based policy and the inputs that you provide during simulation. The policy simulator results can differ from your live AWS environment. We recommend that you check your policies against your live AWS environment after testing using the policy simulator to confirm that you have the desired results. For more information about using the policy simulator, see Testing IAM policies with the IAM policy simulator in the IAM User Guide.

Request Parameters

For information about the parameters that are common to all actions, see Common Parameters.

ActionNames.member.N

A list of names of API operations to evaluate in the simulation. Each operation is evaluated for each resource. Each operation must include the service identifier, such as iam:CreateUser.

Type: Array of strings

Length Constraints: Minimum length of 3. Maximum length of 128.

Required: Yes

CallerArn

The ARN of the IAM user that you want to specify as the simulated caller of the API operations. If you do not specify a CallerArn, it defaults to the ARN of the user that you specify in PolicySourceArn, if you specified a user. If you include both a PolicySourceArn (for example, arn:aws:iam::123456789012:user/David) and a CallerArn (for example, arn:aws:iam::123456789012:user/Bob), the result is that you simulate calling the API operations as Bob, as if Bob had David's policies.

You can specify only the ARN of an IAM user. You cannot specify the ARN of an assumed role, federated user, or a service principal.

CallerArn is required if you include a ResourcePolicy and the PolicySourceArn is not the ARN for an IAM user. This is required so that the resource-based policy's Principal element has a value to use in evaluating the policy.

For more information about ARNs, see Amazon Resource Names (ARNs) in the AWS General Reference.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 2048.

Required: No

ContextEntries.member.N

A list of context keys and corresponding values for the simulation to use. Whenever a context key is evaluated in one of the simulated IAM permissions policies, the corresponding value is supplied.

Type: Array of ContextEntry objects

Required: No

Marker

Use this parameter only when paginating results and only after you receive a response indicating that the results are truncated. Set it to the value of the Marker element in the response that you received to indicate where the next call should start.

Type: String

Length Constraints: Minimum length of 1.

Pattern: [\u0020-\u00FF]+

Required: No

MaxItems

Use this only when paginating results to indicate the maximum number of items you want in the response. If additional items exist beyond the maximum you specify, the IsTruncated response element is true.

If you do not include this parameter, the number of items defaults to 100. Note that IAM might return fewer results, even when there are more results available. In that case, the IsTruncated response element returns true, and Marker contains a value to include in the subsequent call that tells the service where to continue from.

Type: Integer

Valid Range: Minimum value of 1. Maximum value of 1000.

Required: No

PermissionsBoundaryPolicyInputList.member.N

The IAM permissions boundary policy to simulate. The permissions boundary sets the maximum permissions that the entity can have. You can input only one permissions boundary when you pass a policy to this operation. An IAM entity can only have one permissions boundary in effect at a time. For example, if a permissions boundary is attached to an entity and you pass in a different permissions boundary policy using this parameter, then the new permissions boundary policy is used for the simulation. For more information about permissions boundaries, see Permissions boundaries for IAM entities in the IAM User Guide. The policy input is specified as a string containing the complete, valid JSON text of a permissions boundary policy.

The maximum length of the policy document that you can pass in this operation, including whitespace, is listed below. To view the maximum character counts of a managed policy with no whitespaces, see IAM and AWS STS character quotas.

The regex pattern used to validate this parameter is a string of characters consisting of the following:

Any printable ASCII character ranging from the space character (\u0020) through the end of the ASCII character range
The printable characters in the Basic Latin and Latin-1 Supplement character set (through \u00FF)
The special characters tab (\u0009), line feed (\u000A), and carriage return (\u000D)

Type: Array of strings

Length Constraints: Minimum length of 1. Maximum length of 131072.

Pattern: [\u0009\u000A\u000D\u0020-\u00FF]+

Required: No

PolicyInputList.member.N

An optional list of additional policy documents to include in the simulation. Each document is specified as a string containing the complete, valid JSON text of an IAM policy.

The regex pattern used to validate this parameter is a string of characters consisting of the following:

Any printable ASCII character ranging from the space character (\u0020) through the end of the ASCII character range
The printable characters in the Basic Latin and Latin-1 Supplement character set (through \u00FF)
The special characters tab (\u0009), line feed (\u000A), and carriage return (\u000D)

Type: Array of strings

Length Constraints: Minimum length of 1. Maximum length of 131072.

Pattern: [\u0009\u000A\u000D\u0020-\u00FF]+

Required: No

PolicySourceArn

The Amazon Resource Name (ARN) of a user, group, or role whose policies you want to include in the simulation. If you specify a user, group, or role, the simulation includes all policies that are associated with that entity. If you specify a user, the simulation also includes all policies that are attached to any groups the user belongs to.

For more information about ARNs, see Amazon Resource Names (ARNs) in the AWS General Reference.

Type: String

Length Constraints: Minimum length of 20. Maximum length of 2048.

Required: Yes

ResourceArns.member.N

A list of ARNs of AWS resources to include in the simulation. If this parameter is not provided, then the value defaults to * (all resources). Each API in the ActionNames parameter is evaluated for each resource in this list. The simulation determines the access result (allowed or denied) of each combination and reports it in the response. You can simulate resources that don't exist in your account.

The simulation does not automatically retrieve policies for the specified resources. If you want to include a resource policy in the simulation, then you must include the policy as a string in the ResourcePolicy parameter.

For more information about ARNs, see Amazon Resource Names (ARNs) in the AWS General Reference.

Note

Simulation of resource-based policies isn't supported for IAM roles.

Type: Array of strings

Length Constraints: Minimum length of 1. Maximum length of 2048.

Required: No

ResourceHandlingOption

Specifies the type of simulation to run. Different API operations that support resource-based policies require different combinations of resources. By specifying the type of simulation to run, you enable the policy simulator to enforce the presence of the required resources to ensure reliable simulation results. If your simulation does not match one of the following scenarios, then you can omit this parameter. The following list shows each of the supported scenario values and the resources that you must define to run the simulation.

Each of the Amazon EC2 scenarios requires that you specify instance, image, and security group resources. If your scenario includes an EBS volume, then you must specify that volume as a resource. If the Amazon EC2 scenario includes VPC, then you must supply the network interface resource. If it includes an IP subnet, then you must specify the subnet resource. For more information on the Amazon EC2 scenario options, see Supported platforms in the Amazon EC2 User Guide.

EC2-VPC-InstanceStore

instance, image, security group, network interface
EC2-VPC-InstanceStore-Subnet

instance, image, security group, network interface, subnet
EC2-VPC-EBS

instance, image, security group, network interface, volume
EC2-VPC-EBS-Subnet

instance, image, security group, network interface, subnet, volume

Type: String

Length Constraints: Minimum length of 1. Maximum length of 64.

Required: No

ResourceOwner

An AWS account ID that specifies the owner of any simulated resource that does not identify its owner in the resource ARN. Examples of resource ARNs include an S3 bucket or object. If ResourceOwner is specified, it is also used as the account owner of any ResourcePolicy included in the simulation. If the ResourceOwner parameter is not specified, then the owner of the resources and the resource policy defaults to the account of the identity provided in CallerArn. This parameter is required only if you specify a resource-based policy and account that owns the resource is different from the account that owns the simulated calling user CallerArn.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 2048.

Required: No

ResourcePolicy

A resource-based policy to include in the simulation provided as a string. Each resource in the simulation is treated as if it had this policy attached. You can include only one resource-based policy in a simulation.

The regex pattern used to validate this parameter is a string of characters consisting of the following:

Any printable ASCII character ranging from the space character (\u0020) through the end of the ASCII character range
The printable characters in the Basic Latin and Latin-1 Supplement character set (through \u00FF)
The special characters tab (\u0009), line feed (\u000A), and carriage return (\u000D)

Note

Simulation of resource-based policies isn't supported for IAM roles.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 131072.

Pattern: [\u0009\u000A\u000D\u0020-\u00FF]+

Required: No

Response Elements

The following elements are returned by the service.

EvaluationResults.member.N

The results of the simulation.

Type: Array of EvaluationResult objects

IsTruncated

A flag that indicates whether there are more items to return. If your results were truncated, you can make a subsequent pagination request using the Marker request parameter to retrieve more items. Note that IAM might return fewer than the MaxItems number of results even when there are more results available. We recommend that you check IsTruncated after every call to ensure that you receive all your results.

Type: Boolean

Marker

When IsTruncated is true, this element is present and contains the value to use for the Marker parameter in a subsequent pagination request.

Type: String

Errors

For information about the errors that are common to all actions, see Common Errors.

InvalidInput

The request was rejected because an invalid or out-of-range value was supplied for an input parameter.

HTTP Status Code: 400

NoSuchEntity

The request was rejected because it referenced a resource entity that does not exist. The error message describes the resource.

HTTP Status Code: 404

PolicyEvaluation

The request failed because a provided policy could not be successfully evaluated. An additional detailed message indicates the source of the failure.

HTTP Status Code: 500

Examples

Example: Simulating a Policy

This example simulates calling the Amazon S3 API operations GetObject, PutObject, and DeleteObject for a specific S3 bucket. The simulation includes all policies that are attached to the user Jill. In this example, the user Jill has only the managed policy "AmazonS3ReadOnlyAccess" attached. Note that all parameters are shown in unencoded form here for clarity but must be URL encoded to be included as a part of a real HTML request. In the results, the simulation shows that Jill can add new files to the bucket because of the additional policy specified as a string parameter. In addition, she can read from the bucket because of the managed policy attached to the user. However, she cannot delete anything from the S3 bucket because of the default implicitDeny.

Sample Request



https://iam.amazonaws.com/Action=SimulatePrincipalPolicy
&ActionNames.member.1=s3:PutObject
&ActionNames.member.2=s3:GetObject
&ActionNames.member.3=s3:DeleteObject
&ResourceArns.member.1="arn:aws:s3:::my-test-bucket"
&PolicySourceArn=arn:aws:iam:::user/Jill
&PolicyInputList.member.1='{
  "Version":"2012-10-17",
  "Statement":{
    "Effect":"Allow",
    "Action":"s3:PutObject",
    "Resource":"arn:aws:s3:::my-test-bucket"
  }
}'
&Version=2010-05-08
&AUTHPARAMS

Sample Response



<SimulatePrincipalPolicyResponse xmlns="https://iam.amazonaws.com/doc/2010-05-08/">
  <SimulatePrincipalPolicyResult>
    <IsTruncated>false</IsTruncated>
    <EvaluationResults>
      <member>
        <MatchedStatements>
          <member>
            <SourcePolicyId>PolicyInputList.1</SourcePolicyId>
            <EndPosition>
              <Column>4</Column>
              <Line>7</Line>
            </EndPosition>
            <StartPosition>
              <Column>16</Column>
              <Line>3</Line>
            </StartPosition>
          </member>
        </MatchedStatements>
        <MissingContextValues/>
        <EvalResourceName>arn:aws:s3:::my-test-bucket</EvalResourceName>
        <EvalDecision>allowed</EvalDecision>
        <EvalActionName>s3:PutObject</EvalActionName>
      </member>
      <member>
        <MatchedStatements>
          <member>
            <SourcePolicyId>AmazonS3ReadOnlyAccess</SourcePolicyId>
            <EndPosition>
              <Column>6</Column>
              <Line>11</Line>
            </EndPosition>
            <StartPosition>
              <Column>17</Column>
              <Line>3</Line>
            </StartPosition>
          </member>
        </MatchedStatements>
        <MissingContextValues/>
        <EvalResourceName>arn:aws:s3:::my-test-bucket</EvalResourceName>
        <EvalDecision>allowed</EvalDecision>
        <EvalActionName>s3:GetObject</EvalActionName>
      </member>
      <member>
        <MatchedStatements/>
        <MissingContextValues/>
        <EvalResourceName>arn:aws:s3:::my-test-bucket</EvalResourceName>
        <EvalDecision>implicitDeny</EvalDecision>
        <EvalActionName>s3:DeleteObject</EvalActionName>
      </member>
    </EvaluationResults>
  </SimulatePrincipalPolicyResult>
  <ResponseMetadata>
    <RequestId>004d7059-4c14-11e5-b121-bd8c7EXAMPLE</RequestId>
  </ResponseMetadata>
</SimulatePrincipalPolicyResponse>

Example: Same-Account Simulation

This example evaluates policies in the same account only. The simulated user Mateo has an identity-based policy attached that allows the iam:GetRole action. The permissions boundary policy specified in the simulation allows all IAM and S3 actions. Note that for same-account simulations where a resource ARN is specified, the EvalDecisionDetails parameter is returned, but the response is empty.

Sample Request


    
https://iam.amazonaws.com/Action=SimulatePrincipalPolicy
&ActionNames.member.1=iam:GetRole
&ResourceArns.member.1="arn:aws:iam::111122223333:role/pol-sim-test"
&PolicySourceArn=arn:aws:iam::111122223333:user/mateo
&PermissionsBoundaryPolicyInputList.member.1='{
  "Version":"2012-10-17",
  "Statement":{
    "Effect":"Allow",
    "Action":{"iam:*","s3:*"},
    "Resource":{"*"}
  }
}'
&Version=2010-05-08
&AUTHPARAMS

Sample Response


<SimulatePrincipalPolicyResponse xmlns="https://iam.amazonaws.com/doc/2010-05-08/">
    <SimulatePrincipalPolicyResult>
        <IsTruncated>false</IsTruncated>
        <EvaluationResults>
            <member>
                <EvalDecisionDetails/>
                <PermissionsBoundaryDecisionDetail>
                    <AllowedByPermissionsBoundary>true</AllowedByPermissionsBoundary>
                </PermissionsBoundaryDecisionDetail>
                <MatchedStatements>
                    <member>
                        <SourcePolicyId>user_admin_AdminUser</SourcePolicyId>
                        <EndPosition>
                            <Column>84</Column>
                            <Line>1</Line>
                        </EndPosition>
                        <SourcePolicyType>IAM Policy</SourcePolicyType>
                        <StartPosition>
                            <Column>38</Column>
                            <Line>1</Line>
                        </StartPosition>
                    </member>
                </MatchedStatements>
                <MissingContextValues/>
                <EvalResourceName>arn:aws:iam::111122223333:role/pol-sim-test</EvalResourceName>
                <EvalDecision>allowed</EvalDecision>
                <EvalActionName>iam:GetRole</EvalActionName>
                <ResourceSpecificResults>
                    <member>
                        <PermissionsBoundaryDecisionDetail>
                            <AllowedByPermissionsBoundary>true</AllowedByPermissionsBoundary>
                        </PermissionsBoundaryDecisionDetail>
                        <MatchedStatements>
                            <member>
                                <SourcePolicyId>user_admin_AdminUser</SourcePolicyId>
                                <EndPosition>
                                    <Column>84</Column>
                                    <Line>1</Line>
                                </EndPosition>
                                <SourcePolicyType>IAM Policy</SourcePolicyType>
                                <StartPosition>
                                    <Column>38</Column>
                                    <Line>1</Line>
                                </StartPosition>
                            </member>
                        </MatchedStatements>
                        <EvalResourceDecision>allowed</EvalResourceDecision>
                        <MissingContextValues/>
                        <EvalResourceName>arn:aws:iam::111122223333:role/pol-sim-test</EvalResourceName>
                    </member>
                </ResourceSpecificResults>
            </member>
        </EvaluationResults>
    </SimulatePrincipalPolicyResult>
    <ResponseMetadata>
        <RequestId>896e97bd-ff20-47d0-9f91-5d696EXAMPLE</RequestId>
    </ResponseMetadata>
</SimulatePrincipalPolicyResponse>

Example: Cross-Account Simulation

This example is for a simulation that evaluates policies in two accounts. The resource-based policy allows the s3:PutObject action for the user Arnav on Mary's bucket in Account 2. However, the overall result of the simulation for the action is implicitly denied. Arnav's identity-based policy in Account 1 does not allow the action. Additionally, the permissions boundary set for Arnav in Account 1 does not allow S3 actions. The results of each of the policy types included in the simulation is returned in the EvalDecisionDetails parameter.

Sample Request


https://iam.amazonaws.com/Action=SimulatePrincipalPolicy
&ActionNames.member.1=s3:PutObject
&ResourceArns.member.1="arn:aws:s3:::mary/Test"
&ResourceOwner=arn:aws:iam::123456789012:root 
&PolicySourceArn=arn:aws:iam::444455556666:user/arnav
&PermissionsBoundaryPolicyInputList.member.1='{
  "Version":"2012-10-17",
  "Statement":{
    "Effect":"Allow",
    "Action":{"iam:*"},
    "Resource":{"*"}
 }
}'
&ResourcePolicy='{
  "Version":"2012-10-17",
  "Statement":{
    "Effect":"Allow",
    "Principal":{"AWS":"arn:aws:iam::444455556666:user/arnav"}
    "Action":{"s3:List*","s3:Put*"},
    "Resource":{"arn:aws:s3:::mary/*"}
 }
}'
&Version=2010-05-08
&AUTHPARAMS

Sample Response


SimulatePrincipalPolicyResponse xmlns="https://iam.amazonaws.com/doc/2010-05-08/">
    <SimulatePrincipalPolicyResult>
        <IsTruncated>false</IsTruncated>
        <EvaluationResults>
            <member>
                <EvalDecisionDetails>
                    <entry>
                        <key>IAM Policy</key>
                        <value>implicitDeny</value>
                    </entry>
                    <entry>
                        <key>Resource Policy</key>
                        <value>allowed</value>
                    </entry>
                    <entry>
                        <key>Permissions Boundary Policy</key>
                        <value>implicitDeny</value>
                    </entry>
                </EvalDecisionDetails>
                <PermissionsBoundaryDecisionDetail>
                    <AllowedByPermissionsBoundary>false</AllowedByPermissionsBoundary>
                </PermissionsBoundaryDecisionDetail>
                <MatchedStatements/>
                <MissingContextValues/>
                <EvalResourceName>arn:aws:s3:::mary/Test</EvalResourceName>
                <EvalDecision>implicitDeny</EvalDecision>
                <EvalActionName>s3:PutObject</EvalActionName>
                <ResourceSpecificResults>
                    <member>
                        <EvalDecisionDetails>
                            <entry>
                                <key>Permissions Boundary Policy</key>
                                <value>implicitDeny</value>
                            </entry>
                            <entry>
                                <key>IAM Policy</key>
                                <value>implicitDeny</value>
                            </entry>
                            <entry>
                                <key>Resource Policy</key>
                                <value>allowed</value>
                            </entry>
                        </EvalDecisionDetails>
                        <PermissionsBoundaryDecisionDetail>
                            <AllowedByPermissionsBoundary>false</AllowedByPermissionsBoundary>
                        </PermissionsBoundaryDecisionDetail>
                        <MatchedStatements>
                            <member>
                                <SourcePolicyId>ResourcePolicy</SourcePolicyId>
                                <EndPosition>
                                    <Column>259</Column>
                                    <Line>1</Line>
                                </EndPosition>
                                <SourcePolicyType>Resource Policy</SourcePolicyType>
                                <StartPosition>
                                    <Column>68</Column>
                                    <Line>1</Line>
                                </StartPosition>
                            </member>
                        </MatchedStatements>
                        <EvalResourceDecision>implicitDeny</EvalResourceDecision>
                        <MissingContextValues/>
                        <EvalResourceName>arn:aws:s3:::mary/Test</EvalResourceName>
                    </member>
                </ResourceSpecificResults>
            </member>
        </EvaluationResults>
    </SimulatePrincipalPolicyResult>
    <ResponseMetadata>
        <RequestId>3ebb073c-781a-437e-81a9-2a88eEXAMPLE</RequestId>
    </ResponseMetadata>
</SimulatePrincipalPolicyResponse>