Namespace Amazon.CDK.AWS.IAM
AWS Identity and Access Management Construct Library
---Define a role and add permissions to it. This will automatically create and attach an IAM policy to the role:
// Example automatically generated. See https://github.com/aws/jsii/issues/826
Role role = new Role(this, "MyRole", new RoleProps {
AssumedBy = new ServicePrincipal("sns.amazonaws.com")
});
role.AddToPolicy(new PolicyStatement(new PolicyStatementProps {
Resources = new [] { "*" },
Actions = new [] { "lambda:InvokeFunction" }
}));
Define a policy and attach it to groups, users and roles. Note that it is possible to attach
the policy either by calling xxx.attachInlinePolicy(policy)
or policy.attachToXxx(xxx)
.
// Example automatically generated. See https://github.com/aws/jsii/issues/826
User user = new User(this, "MyUser", new UserProps { Password = SecretValue.PlainText("1234") });
Group group = new Group(this, "MyGroup");
Policy policy = new Policy(this, "MyPolicy");
policy.AttachToUser(user);
group.AttachInlinePolicy(policy);
Managed policies can be attached using xxx.addManagedPolicy(ManagedPolicy.fromAwsManagedPolicyName(policyName))
:
// Example automatically generated. See https://github.com/aws/jsii/issues/826
Group group = new Group(this, "MyGroup");
group.AddManagedPolicy(ManagedPolicy.FromAwsManagedPolicyName("AdministratorAccess"));
Granting permissions to resources
Many of the AWS CDK resources have grant*
methods that allow you to grant other resources access to that resource. As an example, the following code gives a Lambda function write permissions (Put, Update, Delete) to a DynamoDB table.
// Example automatically generated. See https://github.com/aws/jsii/issues/826
Function fn = new Function(this, "Function", functionProps);
Table table = new Table(this, "Table", tableProps);
table.GrantWriteData(fn);
The more generic grant
method allows you to give specific permissions to a resource:
// Example automatically generated. See https://github.com/aws/jsii/issues/826
Function fn = new Function(this, "Function", functionProps);
Table table = new Table(this, "Table", tableProps);
table.Grant(fn, "dynamodb:PutItem");
The grant*
methods accept an IGrantable
object. This interface is implemented by IAM principlal resources (groups, users and roles) and resources that assume a role such as a Lambda function, EC2 instance or a Codebuild project.
You can find which grant*
methods exist for a resource in the AWS CDK API Reference.
Roles
Many AWS resources require Roles to operate. These Roles define the AWS API calls an instance or other AWS service is allowed to make.
Creating Roles and populating them with the right permissions Statements is a necessary but tedious part of setting up AWS infrastructure. In order to help you focus on your business logic, CDK will take care of creating roles and populating them with least-privilege permissions automatically.
All constructs that require Roles will create one for you if don't specify
one at construction time. Permissions will be added to that role
automatically if you associate the construct with other constructs from the
AWS Construct Library (for example, if you tell an AWS CodePipeline to trigger
an AWS Lambda Function, the Pipeline's Role will automatically get
lambda:InvokeFunction
permissions on that particular Lambda Function),
or if you explicitly grant permissions using grant
functions (see the
previous section).
Opting out of automatic permissions management
You may prefer to manage a Role's permissions yourself instead of having the CDK automatically manage them for you. This may happen in one of the following cases:
To prevent constructs from updating your Role's policy, pass the object
returned by myRole.withoutPolicyUpdates()
instead of myRole
itself.
For example, to have an AWS CodePipeline not automatically add the required permissions to trigger the expected targets, do the following:
// Example automatically generated. See https://github.com/aws/jsii/issues/826
Role role = new Role(this, "Role", new RoleProps {
AssumedBy = new ServicePrincipal("codepipeline.amazonaws.com"),
// custom description if desired
Description = "This is a custom role..."
});
new Pipeline(this, "Pipeline", new PipelineProps {
// Give the Pipeline an immutable view of the Role
Role = role.WithoutPolicyUpdates()
});
// You now have to manage the Role policies yourself
role.AddToPolicy(new PolicyStatement(new PolicyStatementProps {
Actions = new [] { },
Resources = new [] { }
}));
Using existing roles
If there are Roles in your account that have already been created which you
would like to use in your CDK application, you can use Role.fromRoleArn
to
import them, as follows:
// Example automatically generated. See https://github.com/aws/jsii/issues/826
IRole role = Role.FromRoleArn(this, "Role", "arn:aws:iam::123456789012:role/MyExistingRole", new FromRoleArnOptions {
// Set 'mutable' to 'false' to use the role as-is and prevent adding new
// policies to it. The default is 'true', which means the role may be
// modified as part of the deployment.
Mutable = false
});
Configuring an ExternalId
If you need to create Roles that will be assumed by third parties, it is generally a good idea to require an ExternalId
to assume them. Configuring
an ExternalId
works like this:
// Example automatically generated. See https://github.com/aws/jsii/issues/826
Role role = new Role(this, "MyRole", new RoleProps {
AssumedBy = new AccountPrincipal("123456789012"),
ExternalIds = new [] { "SUPPLY-ME" }
});
Principals vs Identities
When we say Principal, we mean an entity you grant permissions to. This
entity can be an AWS Service, a Role, or something more abstract such as "all
users in this account" or even "all users in this organization". An
Identity is an IAM representing a single IAM entity that can have
a policy attached, one of Role
, User
, or Group
.
IAM Principals
When defining policy statements as part of an AssumeRole policy or as part of a
resource policy, statements would usually refer to a specific IAM principal
under Principal
.
IAM principals are modeled as classes that derive from the iam.PolicyPrincipal
abstract class. Principal objects include principal type (string) and value
(array of string), optional set of conditions and the action that this principal
requires when it is used in an assume role policy document.
To add a principal to a policy statement you can either use the abstract
statement.addPrincipal
, one of the concrete addXxxPrincipal
methods:
If multiple principals are added to the policy statement, they will be merged together:
// Example automatically generated. See https://github.com/aws/jsii/issues/826
PolicyStatement statement = new PolicyStatement();
statement.AddServicePrincipal("cloudwatch.amazonaws.com");
statement.AddServicePrincipal("ec2.amazonaws.com");
statement.AddArnPrincipal("arn:aws:boom:boom");
Will result in:
{
"Principal": {
"Service": [ "cloudwatch.amazonaws.com", "ec2.amazonaws.com" ],
"AWS": "arn:aws:boom:boom"
}
}
The CompositePrincipal
class can also be used to define complex principals, for example:
// Example automatically generated. See https://github.com/aws/jsii/issues/826
Role role = new Role(this, "MyRole", new RoleProps {
AssumedBy = new CompositePrincipal(
new ServicePrincipal("ec2.amazonaws.com"),
new AccountPrincipal("1818188181818187272"))
});
The PrincipalWithConditions
class can be used to add conditions to a
principal, especially those that don't take a conditions
parameter in their
constructor. The principal.withConditions()
method can be used to create a
PrincipalWithConditions
from an existing principal, for example:
// Example automatically generated. See https://github.com/aws/jsii/issues/826
IPrincipal principal = new AccountPrincipal("123456789000").WithConditions(new Dictionary<string, object> { { "StringEquals", new Struct { Foo = "baz" } } });
NOTE: If you need to define an IAM condition that uses a token (such as a
deploy-time attribute of another resource) in a JSON map key, use <code>CfnJson</code> to
render this condition. See <a href="./test/integ-condition-with-ref.ts">this test</a> for
an example.
The WebIdentityPrincipal
class can be used as a principal for web identities like
Cognito, Amazon, Google or Facebook, for example:
// Example automatically generated. See https://github.com/aws/jsii/issues/826
IPrincipal principal = new WebIdentityPrincipal("cognito-identity.amazonaws.com").WithConditions(new Dictionary<string, object> {
{ "StringEquals", new Struct { Cognito-identity.amazonaws.com:aud = "us-east-2:12345678-abcd-abcd-abcd-123456" } },
{ "ForAnyValue:StringLike", new Struct { Cognito-identity.amazonaws.com:amr = "unauthenticated" } }
});
Parsing JSON Policy Documents
The PolicyDocument.fromJson
and PolicyStatement.fromJson
static methods can be used to parse JSON objects. For example:
// Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
__object policyDocument = new Dictionary<string, object> {
{ "Version", "2012-10-17" },
{ "Statement", new [] { new Dictionary<string, object> {
{ "Sid", "FirstStatement" },
{ "Effect", "Allow" },
{ "Action", new [] { "iam:ChangePassword" } },
{ "Resource", "*" }
}, new Dictionary<string, string> {
{ "Sid", "SecondStatement" },
{ "Effect", "Allow" },
{ "Action", "s3:ListAllMyBuckets" },
{ "Resource", "*" }
}, new Dictionary<string, object> {
{ "Sid", "ThirdStatement" },
{ "Effect", "Allow" },
{ "Action", new [] { "s3:List*", "s3:Get*" } },
{ "Resource", new [] { "arn:aws:s3:::confidential-data", "arn:aws:s3:::confidential-data/*" } },
{ "Condition", new Dictionary<string, IDictionary<string, string>> { { "Bool", new Dictionary<string, string> { { "aws:MultiFactorAuthPresent", "true" } } } } }
} } }
};
PolicyDocument customPolicyDocument = PolicyDocument.FromJson(policyDocument);
// You can pass this document as an initial document to a ManagedPolicy
// or inline Policy.
var newManagedPolicy = new ManagedPolicy(stack, "MyNewManagedPolicy", new Struct {
Document = customPolicyDocument
});
var newPolicy = new Policy(stack, "MyNewPolicy", new Struct {
Document = customPolicyDocument
});
Permissions Boundaries
Permissions
Boundaries
can be used as a mechanism to prevent privilege esclation by creating new
Role
s. Permissions Boundaries are a Managed Policy, attached to Roles or
Users, that represent the maximum set of permissions they can have. The
effective set of permissions of a Role (or User) will be the intersection of
the Identity Policy and the Permissions Boundary attached to the Role (or
User). Permissions Boundaries are typically created by account
Administrators, and their use on newly created Role
s will be enforced by
IAM policies.
It is possible to attach Permissions Boundaries to all Roles created in a construct tree all at once:
// Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
// This imports an existing policy.
IManagedPolicy boundary = ManagedPolicy.FromManagedPolicyArn(this, "Boundary", "arn:aws:iam::123456789012:policy/boundary");
// This creates a new boundary
ManagedPolicy boundary2 = new ManagedPolicy(this, "Boundary2", new ManagedPolicyProps {
Statements = new [] {
new PolicyStatement(new PolicyStatementProps {
Effect = Effect.DENY,
Actions = new [] { "iam:*" },
Resources = new [] { "*" }
}) }
});
// Directly apply the boundary to a Role you create
PermissionsBoundary.Of(role).Apply(boundary);
// Apply the boundary to an Role that was implicitly created for you
PermissionsBoundary.Of(lambdaFunction).Apply(boundary);
// Apply the boundary to all Roles in a stack
PermissionsBoundary.Of(stack).Apply(boundary);
// Remove a Permissions Boundary that is inherited, for example from the Stack level
PermissionsBoundary.Of(customResource).Clear();
OpenID Connect Providers
OIDC identity providers are entities in IAM that describe an external identity provider (IdP) service that supports the OpenID Connect (OIDC) standard, such as Google or Salesforce. You use an IAM OIDC identity provider when you want to establish trust between an OIDC-compatible IdP and your AWS account. This is useful when creating a mobile app or web application that requires access to AWS resources, but you don't want to create custom sign-in code or manage your own user identities. For more information about this scenario, see [About Web Identity Federation] and the relevant documentation in the [Amazon Cognito Identity Pools Developer Guide].
The following examples defines an OpenID Connect provider. Two client IDs (audiences) are will be able to send authentication requests to https://openid/connect.
// Example automatically generated. See https://github.com/aws/jsii/issues/826
OpenIdConnectProvider provider = new OpenIdConnectProvider(this, "MyProvider", new OpenIdConnectProviderProps {
Url = "https://openid/connect",
ClientIds = new [] { "myclient1", "myclient2" }
});
You can specify an optional list of thumbprints
. If not specified, the
thumbprint of the root certificate authority (CA) will automatically be obtained
from the host as described
here.
Once you define an OpenID connect provider, you can use it with AWS services that expect an IAM OIDC provider. For example, when you define an Amazon Cognito identity pool you can reference the provider's ARN as follows:
// Example automatically generated. See https://github.com/aws/jsii/issues/826
new CfnIdentityPool(this, "IdentityPool", new CfnIdentityPoolProps {
OpenIdConnectProviderArns = new [] { myProvider.OpenIdConnectProviderArn },
// And the other properties for your identity pool
AllowUnauthenticatedIdentities = allowUnauthenticatedIdentities
});
The OpenIdConnectPrincipal
class can be used as a principal used with a OpenIdConnectProvider
, for example:
// Example automatically generated. See https://github.com/aws/jsii/issues/826
OpenIdConnectProvider provider = new OpenIdConnectProvider(this, "MyProvider", new OpenIdConnectProviderProps {
Url = "https://openid/connect",
ClientIds = new [] { "myclient1", "myclient2" }
});
OpenIdConnectPrincipal principal = new OpenIdConnectPrincipal(provider);
Users
IAM manages users for your AWS account. To create a new user:
// Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
var user = new User(this, "MyUser");
To import an existing user by name with path:
// Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
var user = User.FromUserName(stack, "MyImportedUserByName", "johnsmith");
To import an existing user by ARN:
// Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
var user = User.FromUserArn(this, "MyImportedUserByArn", "arn:aws:iam::123456789012:user/johnsmith");
To import an existing user by attributes:
// Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
var user = User.FromUserAttributes(stack, "MyImportedUserByAttributes", new Struct {
UserArn = "arn:aws:iam::123456789012:user/johnsmith"
});
Features
Classes
AccountPrincipal | Specify AWS account ID as the principal entity in a policy to delegate authority to the account. |
AccountRootPrincipal | Use the AWS account into which a stack is deployed as the principal entity in a policy. |
AddToPrincipalPolicyResult | Result of calling |
AddToResourcePolicyResult | Result of calling addToResourcePolicy. |
Anyone | (deprecated) A principal representing all identities in all accounts. |
AnyPrincipal | A principal representing all identities in all accounts. |
ArnPrincipal | Specify a principal by the Amazon Resource Name (ARN). |
CanonicalUserPrincipal | A policy principal for canonicalUserIds - useful for S3 bucket policies that use Origin Access identities. |
CfnAccessKey | A CloudFormation |
CfnAccessKeyProps | Properties for defining a |
CfnGroup | A CloudFormation |
CfnGroup.PolicyProperty | |
CfnGroupProps | Properties for defining a |
CfnInstanceProfile | A CloudFormation |
CfnInstanceProfileProps | Properties for defining a |
CfnManagedPolicy | A CloudFormation |
CfnManagedPolicyProps | Properties for defining a |
CfnPolicy | A CloudFormation |
CfnPolicyProps | Properties for defining a |
CfnRole | A CloudFormation |
CfnRole.PolicyProperty | |
CfnRoleProps | Properties for defining a |
CfnServiceLinkedRole | A CloudFormation |
CfnServiceLinkedRoleProps | Properties for defining a |
CfnUser | A CloudFormation |
CfnUser.LoginProfileProperty | |
CfnUser.PolicyProperty | |
CfnUserProps | Properties for defining a |
CfnUserToGroupAddition | A CloudFormation |
CfnUserToGroupAdditionProps | Properties for defining a |
CommonGrantOptions | (experimental) Basic options for a grant operation. |
CompositeDependable | Composite dependable. |
CompositePrincipal | Represents a principal that has multiple types of principals. |
Effect | The Effect element of an IAM policy. |
FederatedPrincipal | Principal entity that represents a federated identity provider such as Amazon Cognito, that can be used to provide temporary security credentials to users who have been authenticated. |
FromRoleArnOptions | Options allowing customizing the behavior of {@link Role.fromRoleArn}. |
Grant | Result of a grant() operation. |
GrantOnPrincipalAndResourceOptions | (experimental) Options for a grant operation to both identity and resource. |
GrantOnPrincipalOptions | (experimental) Options for a grant operation that only applies to principals. |
GrantWithResourceOptions | (experimental) Options for a grant operation. |
Group | An IAM Group (collection of IAM users) lets you specify permissions for multiple users, which can make it easier to manage permissions for those users. |
GroupProps | Properties for defining an IAM group. |
LazyRole | An IAM role that only gets attached to the construct tree once it gets used, not before. |
LazyRoleProps | Properties for defining a LazyRole. |
ManagedPolicy | Managed policy. |
ManagedPolicyProps | Properties for defining an IAM managed policy. |
OpenIdConnectPrincipal | A principal that represents a federated identity provider as from a OpenID Connect provider. |
OpenIdConnectProvider | (experimental) IAM OIDC identity providers are entities in IAM that describe an external identity provider (IdP) service that supports the OpenID Connect (OIDC) standard, such as Google or Salesforce. |
OpenIdConnectProviderProps | (experimental) Initialization properties for |
OrganizationPrincipal | A principal that represents an AWS Organization. |
PermissionsBoundary | Modify the Permissions Boundaries of Users and Roles in a construct tree. |
Policy | The AWS::IAM::Policy resource associates an IAM policy with IAM users, roles, or groups. |
PolicyDocument | A PolicyDocument is a collection of statements. |
PolicyDocumentProps | Properties for a new PolicyDocument. |
PolicyProps | Properties for defining an IAM inline policy document. |
PolicyStatement | Represents a statement in an IAM policy document. |
PolicyStatementProps | Interface for creating a policy statement. |
PrincipalBase | Base class for policy principals. |
PrincipalPolicyFragment | A collection of the fields in a PolicyStatement that can be used to identify a principal. |
PrincipalWithConditions | An IAM principal with additional conditions specifying when the policy is in effect. |
Role | IAM Role. |
RoleProps | Properties for defining an IAM Role. |
ServicePrincipal | An IAM principal that represents an AWS service (i.e. sqs.amazonaws.com). |
ServicePrincipalOpts | Options for a service principal. |
UnknownPrincipal | A principal for use in resources that need to have a role but it's unknown. |
UnknownPrincipalProps | Properties for an UnknownPrincipal. |
User | Define a new IAM user. |
UserAttributes | Represents a user defined outside of this stack. |
UserProps | Properties for defining an IAM user. |
WebIdentityPrincipal | A principal that represents a federated identity provider as Web Identity such as Cognito, Amazon, Facebook, Google, etc. |
Interfaces
CfnGroup.IPolicyProperty | |
CfnRole.IPolicyProperty | |
CfnUser.ILoginProfileProperty | |
CfnUser.IPolicyProperty | |
IAddToPrincipalPolicyResult | Result of calling |
IAddToResourcePolicyResult | Result of calling addToResourcePolicy. |
ICfnAccessKeyProps | Properties for defining a |
ICfnGroupProps | Properties for defining a |
ICfnInstanceProfileProps | Properties for defining a |
ICfnManagedPolicyProps | Properties for defining a |
ICfnPolicyProps | Properties for defining a |
ICfnRoleProps | Properties for defining a |
ICfnServiceLinkedRoleProps | Properties for defining a |
ICfnUserProps | Properties for defining a |
ICfnUserToGroupAdditionProps | Properties for defining a |
ICommonGrantOptions | (experimental) Basic options for a grant operation. |
IFromRoleArnOptions | Options allowing customizing the behavior of {@link Role.fromRoleArn}. |
IGrantable | Any object that has an associated principal that a permission can be granted to. |
IGrantOnPrincipalAndResourceOptions | (experimental) Options for a grant operation to both identity and resource. |
IGrantOnPrincipalOptions | (experimental) Options for a grant operation that only applies to principals. |
IGrantWithResourceOptions | (experimental) Options for a grant operation. |
IGroup | Represents an IAM Group. |
IGroupProps | Properties for defining an IAM group. |
IIdentity | A construct that represents an IAM principal, such as a user, group or role. |
ILazyRoleProps | Properties for defining a LazyRole. |
IManagedPolicy | A managed policy. |
IManagedPolicyProps | Properties for defining an IAM managed policy. |
IOpenIdConnectProvider | (experimental) Represents an IAM OpenID Connect provider. |
IOpenIdConnectProviderProps | (experimental) Initialization properties for |
IPolicy | Represents an IAM Policy. |
IPolicyDocumentProps | Properties for a new PolicyDocument. |
IPolicyProps | Properties for defining an IAM inline policy document. |
IPolicyStatementProps | Interface for creating a policy statement. |
IPrincipal | Represents a logical IAM principal. |
IResourceWithPolicy | A resource with a resource policy that can be added to. |
IRole | A Role object. |
IRoleProps | Properties for defining an IAM Role. |
IServicePrincipalOpts | Options for a service principal. |
IUnknownPrincipalProps | Properties for an UnknownPrincipal. |
IUser | Represents an IAM user. |
IUserAttributes | Represents a user defined outside of this stack. |
IUserProps | Properties for defining an IAM user. |