Returns a set of temporary security credentials for users who have been authenticated in a mobile or web application with a web identity provider. Example providers include Amazon Cognito, Login with Amazon, Facebook, Google, or any OpenID Connect-compatible identity provider.
For mobile applications, we recommend that you use Amazon Cognito. You can use Amazon Cognito with the Amazon Web Services SDK for iOS Developer Guide and the Amazon Web Services SDK for Android Developer Guide to uniquely identify a user. You can also supply the user with a consistent identity throughout the lifetime of an application.
To learn more about Amazon Cognito, see Amazon Cognito Overview in Amazon Web Services SDK for Android Developer Guide and Amazon Cognito Overview in the Amazon Web Services SDK for iOS Developer Guide.
AssumeRoleWithWebIdentity does not require the use of Amazon Web Services
security credentials. Therefore, you can distribute an application (for example, on mobile
devices) that requests temporary security credentials without including long-term Amazon Web Services
credentials in the application. You also don't need to deploy server-based proxy services
that use long-term Amazon Web Services credentials. Instead, the identity of the caller is validated by
using a token from the web identity provider. For a comparison of
AssumeRoleWithWebIdentity with the other API operations that produce
temporary credentials, see Requesting Temporary Security
Credentials and Comparing the
Amazon Web Services STS API operations in the IAM User Guide.
The temporary security credentials returned by this API consist of an access key ID, a secret access key, and a security token. Applications can use these temporary security credentials to sign calls to Amazon Web Services service API operations.
By default, the temporary security credentials created by
AssumeRoleWithWebIdentity last for one hour. However, you can use the
DurationSeconds parameter to specify the duration of your session.
You can provide a value from 900 seconds (15 minutes) up to the maximum session duration
setting for the role. This setting can have a value from 1 hour to 12 hours. To learn how
to view the maximum value for your role, see View the
Maximum Session Duration Setting for a Role in the
IAM User Guide. The maximum session duration limit applies when
you use the
AssumeRole* API operations or the
commands. However the limit does not apply when you use those operations to create a
console URL. For more information, see Using IAM Roles in the
IAM User Guide.
The temporary security credentials created by
be used to make API calls to any Amazon Web Services service with the following exception: you cannot
call the STS
(Optional) You can pass inline or managed session policies to this operation. You can pass a single JSON policy document to use as an inline session policy. You can also specify up to 10 managed policies to use as managed session policies. The plaintext that you use for both inline and managed session policies can't exceed 2,048 characters. Passing policies to this operation returns new temporary credentials. The resulting session's permissions are the intersection of the role's identity-based policy and the session policies. You can use the role's temporary credentials in subsequent Amazon Web Services API calls to access resources in the account that owns the role. You cannot use session policies to grant more permissions than those allowed by the identity-based policy of the role that is being assumed. For more information, see Session Policies in the IAM User Guide.
(Optional) You can configure your IdP to pass attributes into your web identity token as session tags. Each session tag consists of a key name and an associated value. For more information about session tags, see Passing Session Tags in STS in the IAM User Guide.
You can pass up to 50 session tags. The plaintext session tag keys can’t exceed 128 characters and the values can’t exceed 256 characters. For these and additional limits, see IAM and STS Character Limits in the IAM User Guide.
An Amazon Web Services conversion compresses the passed session policies and session tags into a
packed binary format that has a separate limit. Your request can fail for this limit
even if your plaintext meets the other requirements. The
response element indicates by percentage how close the policies and tags for your
request are to the upper size limit.
You can pass a session tag with the same key as a tag that is attached to the role. When you do, the session tag overrides the role tag with the same key.
An administrator must grant you the permissions necessary to pass session tags. The administrator can also create granular permissions to allow you to pass only specific session tags. For more information, see Tutorial: Using Tags for Attribute-Based Access Control in the IAM User Guide.
You can set the session tags as transitive. Transitive tags persist during role chaining. For more information, see Chaining Roles with Session Tags in the IAM User Guide.
Before your application can call
AssumeRoleWithWebIdentity, you must have
an identity token from a supported identity provider and create a role that the application
can assume. The role that your application assumes must trust the identity provider that is
associated with the identity token. In other words, the identity provider must be specified
in the role's trust policy.
AssumeRoleWithWebIdentity can result in an entry in your
CloudTrail logs. The entry includes the Subject of
the provided web identity token. We recommend that you avoid using any personally
identifiable information (PII) in this field. For example, you could instead use a GUID
or a pairwise identifier, as suggested
in the OIDC specification.
For more information about how to use web identity federation and the
AssumeRoleWithWebIdentity API, see the following resources:
Web Identity Federation Playground. Walk through the process of authenticating through Login with Amazon, Facebook, or Google, getting temporary security credentials, and then using those credentials to make a request to Amazon Web Services.
Amazon Web Services SDK for iOS Developer Guide and Amazon Web Services SDK for Android Developer Guide. These toolkits contain sample apps that show how to invoke the identity providers. The toolkits then show how to use the information from these providers to get and use temporary security credentials.
Web Identity Federation with Mobile Applications. This article discusses web identity federation and shows an example of how to use web identity federation to get access to content in Amazon S3.