ExAws.Sts.Core
AWS Security Token Service
AWS Security Token Service
The AWS Security Token Service (STS) is a web service that enables you to request temporary, limited-privilege credentials for AWS Identity and Access Management (IAM) users or for users that you authenticate (federated users). This guide provides descriptions of the STS API. For more detailed information about using this service, go to Using Temporary Security Credentials.
Note: As an alternative to using the API, you can use one of the AWS SDKs, which consist of libraries and sample code for various programming languages and platforms (Java, Ruby, .NET, iOS, Android, etc.). The SDKs provide a convenient way to create programmatic access to STS. For example, the SDKs take care of cryptographically signing requests, managing errors, and retrying requests automatically. For information about the AWS SDKs, including how to download and install them, see the Tools for Amazon Web Services page. For information about setting up signatures and authorization through the API, go to Signing AWS API Requests in the AWS General Reference. For general information about the Query API, go to Making Query Requests in Using IAM. For information about using security tokens with other AWS products, go to Using Temporary Security Credentials to Access AWS in Using Temporary Security Credentials.
If you’re new to AWS and need additional technical information about a specific AWS product, you can find the product’s technical documentation at http://aws.amazon.com/documentation/.
Endpoints
The AWS Security Token Service (STS) has a default endpoint of https://sts.amazonaws.com that maps to the US East (N. Virginia) region. Additional regions are available, but must first be activated in the AWS Management Console before you can use a different region’s endpoint. For more information about activating a region for STS see Activating STS in a New Region in the Using Temporary Security Credentials guide.
For information about STS endpoints, see Regions and Endpoints in the AWS General Reference.
Recording API requests
STS supports AWS CloudTrail, which is a service that records AWS calls for your AWS account and delivers log files to an Amazon S3 bucket. By using information collected by CloudTrail, you can determine what requests were successfully made to STS, who made the request, when it was made, and so on. To learn more about CloudTrail, including how to turn it on and find your log files, see the AWS CloudTrail User Guide.
Summary↑
assume_role!(client, input) | Same as |
assume_role(client, input) | AssumeRole |
assume_role_with_saml!(client, input) | Same as |
assume_role_with_saml(client, input) | AssumeRoleWithSAML |
assume_role_with_web_identity!(client, input) | Same as |
assume_role_with_web_identity(client, input) | AssumeRoleWithWebIdentity |
decode_authorization_message!(client, input) | Same as |
decode_authorization_message(client, input) | DecodeAuthorizationMessage |
get_federation_token!(client, input) | Same as |
get_federation_token(client, input) | GetFederationToken |
get_session_token!(client, input) | Same as |
get_session_token(client, input) | GetSessionToken |
Types ↑
federated_user :: [arn: arn_type, federated_user_id: federated_id_type]
access_key_id_type :: binary
arn_type :: binary
subject :: binary
assume_role_response :: [assumed_role_user: assumed_role_user, credentials: credentials, packed_policy_size: non_negative_integer_type]
assume_role_with_web_identity_request :: [duration_seconds: role_duration_seconds_type, policy: session_policy_document_type, provider_id: url_type, role_arn: arn_type, role_session_name: user_name_type, web_identity_token: client_token_type]
get_federation_token_request :: [duration_seconds: duration_seconds_type, name: user_name_type, policy: session_policy_document_type]
serial_number_type :: binary
decoded_message_type :: binary
get_federation_token_response :: [credentials: credentials, federated_user: federated_user, packed_policy_size: non_negative_integer_type]
issuer :: binary
invalid_authorization_message :: binary
assume_role_request :: [duration_seconds: role_duration_seconds_type, external_id: external_id_type, policy: session_policy_document_type, role_arn: arn_type, role_session_name: user_name_type, serial_number: serial_number_type, token_code: token_code_type]
credentials :: [access_key_id: access_key_id_type, expiration: date_type, secret_access_key: access_key_secret_type, session_token: token_type]
access_key_secret_type :: binary
assume_role_with_web_identity_response :: [assumed_role_user: assumed_role_user, audience: audience, credentials: credentials, packed_policy_size: non_negative_integer_type, provider: issuer, subject_from_web_identity_token: web_identity_subject_type]
expired_token_exception :: [{:message, expired_identity_token_message}]
idp_communication_error_exception :: [{:message, idp_communication_error_message}]
invalid_authorization_message_exception :: [{:message, invalid_authorization_message}]
malformed_policy_document_message :: binary
external_id_type :: binary
malformed_policy_document_exception :: [{:message, malformed_policy_document_message}]
decode_authorization_message_response :: [{:decoded_message, decoded_message_type}]
date_type :: integer
client_token_type :: binary
idp_rejected_claim_message :: binary
assume_role_with_saml_response :: [assumed_role_user: assumed_role_user, audience: audience, credentials: credentials, issuer: issuer, name_qualifier: name_qualifier, packed_policy_size: non_negative_integer_type, subject: subject, subject_type: subject_type]
session_policy_document_type :: binary
saml_assertion_type :: binary
assumed_role_id_type :: binary
invalid_identity_token_message :: binary
get_session_token_request :: [duration_seconds: duration_seconds_type, serial_number: serial_number_type, token_code: token_code_type]
idp_communication_error_message :: binary
encoded_message_type :: binary
role_duration_seconds_type :: integer
assumed_role_user :: [arn: arn_type, assumed_role_id: assumed_role_id_type]
web_identity_subject_type :: binary
assume_role_with_saml_request :: [duration_seconds: role_duration_seconds_type, policy: session_policy_document_type, principal_arn: arn_type, role_arn: arn_type, saml_assertion: saml_assertion_type]
name_qualifier :: binary
decode_authorization_message_request :: [{:encoded_message, encoded_message_type}]
non_negative_integer_type :: integer
get_session_token_response :: [{:credentials, credentials}]
invalid_identity_token_exception :: [{:message, invalid_identity_token_message}]
federated_id_type :: binary
audience :: binary
packed_policy_too_large_message :: binary
packed_policy_too_large_exception :: [{:message, packed_policy_too_large_message}]
idp_rejected_claim_exception :: [{:message, idp_rejected_claim_message}]
token_code_type :: binary
token_type :: binary
expired_identity_token_message :: binary
duration_seconds_type :: integer
url_type :: binary
subject_type :: binary
user_name_type :: binary
Functions
Specs:
- assume_role(client :: ExAws.Sts.t, input :: assume_role_request) :: ExAws.Request.Query.response_t
AssumeRole
Returns a set of temporary security credentials (consisting of an access
key ID, a secret access key, and a security token) that you can use to
access AWS resources that you might not normally have access to. Typically,
you use AssumeRole
for cross-account access or federation.
Important: You cannot call AssumeRole
by using AWS account
credentials; access will be denied. You must use IAM user credentials or
temporary security credentials to call AssumeRole
.
For cross-account access, imagine that you own multiple accounts and need to access resources in each account. You could create long-term credentials in each account to access those resources. However, managing all those credentials and remembering which one can access which account can be time consuming. Instead, you can create one set of long-term credentials in one account and then use temporary security credentials to access all the other accounts by assuming roles in those accounts. For more information about roles, see IAM Roles (Delegation and Federation) in Using IAM.
For federation, you can, for example, grant single sign-on access to the
AWS Management Console. If you already have an identity and authentication
system in your corporate network, you don’t have to recreate user
identities in AWS in order to grant those user identities access to AWS.
Instead, after a user has been authenticated, you call AssumeRole
(and
specify the role with the appropriate permissions) to get temporary
security credentials for that user. With those temporary security
credentials, you construct a sign-in URL that users can use to access the
console. For more information, see Scenarios for Granting Temporary
Access in
Using Temporary Security Credentials.
The temporary security credentials are valid for the duration that you
specified when calling AssumeRole
, which can be from 900 seconds (15
minutes) to 3600 seconds (1 hour). The default is 1 hour.
Optionally, you can pass an IAM access policy to this operation. If you choose not to pass a policy, the temporary security credentials that are returned by the operation have the permissions that are defined in the access policy of the role that is being assumed. If you pass a policy to this operation, the temporary security credentials that are returned by the operation have the permissions that are allowed by both the access policy of the role that is being assumed, and the policy that you pass. This gives you a way to further restrict the permissions for the resulting temporary security credentials. You cannot use the passed policy to grant permissions that are in excess of those allowed by the access policy of the role that is being assumed. For more information, see Permissions for AssumeRole, AssumeRoleWithSAML, and AssumeRoleWithWebIdentity in Using Temporary Security Credentials.
To assume a role, your AWS account must be trusted by the role. The trust
relationship is defined in the role’s trust policy when the role is
created. You must also have a policy that allows you to call
sts:AssumeRole
.
Using MFA with AssumeRole
You can optionally include multi-factor authentication (MFA) information
when you call AssumeRole
. This is useful for cross-account scenarios in
which you want to make sure that the user who is assuming the role has been
authenticated using an AWS MFA device. In that scenario, the trust policy
of the role being assumed includes a condition that tests for MFA
authentication; if the caller does not include valid MFA information, the
request to assume the role is denied. The condition in a trust policy that
tests for MFA authentication might look like the following example.
"Condition": {"Bool": {"aws:MultiFactorAuthPresent": true}}
For more information, see Configuring MFA-Protected API Access in Using IAM guide.
To use MFA with AssumeRole
, you pass values for the SerialNumber
and
TokenCode
parameters. The SerialNumber
value identifies the user’s
hardware or virtual MFA device. The TokenCode
is the time-based one-time
password (TOTP) that the MFA devices produces.
Specs:
- assume_role!(client :: ExAws.Sts.t, input :: assume_role_request) :: ExAws.Request.Query.success_t | no_return
Same as assume_role/2
but raise on error.
Specs:
- assume_role_with_saml(client :: ExAws.Sts.t, input :: assume_role_with_saml_request) :: ExAws.Request.Query.response_t
AssumeRoleWithSAML
Returns a set of temporary security credentials for users who have been authenticated via a SAML authentication response. This operation provides a mechanism for tying an enterprise identity store or directory to role-based AWS access without user-specific credentials or configuration.
The temporary security credentials returned by this operation 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 AWS services. The
credentials are valid for the duration that you specified when calling
AssumeRoleWithSAML
, which can be up to 3600 seconds (1 hour) or until the
time specified in the SAML authentication response’s SessionNotOnOrAfter
value, whichever is shorter.
Note:The maximum duration for a session is 1 hour, and the minimum duration is 15 minutes, even if values outside this range are specified. Optionally, you can pass an IAM access policy to this operation. If you choose not to pass a policy, the temporary security credentials that are returned by the operation have the permissions that are defined in the access policy of the role that is being assumed. If you pass a policy to this operation, the temporary security credentials that are returned by the operation have the permissions that are allowed by both the access policy of the role that is being assumed, and the policy that you pass. This gives you a way to further restrict the permissions for the resulting temporary security credentials. You cannot use the passed policy to grant permissions that are in excess of those allowed by the access policy of the role that is being assumed. For more information, see Permissions for AssumeRoleWithSAML in Using Temporary Security Credentials.
Before your application can call AssumeRoleWithSAML
, you must configure
your SAML identity provider (IdP) to issue the claims required by AWS.
Additionally, you must use AWS Identity and Access Management (IAM) to
create a SAML provider entity in your AWS account that represents your
identity provider, and create an IAM role that specifies this SAML provider
in its trust policy.
Calling AssumeRoleWithSAML
does not require the use of AWS security
credentials. The identity of the caller is validated by using keys in the
metadata document that is uploaded for the SAML provider entity for your
identity provider.
For more information, see the following resources:
Creating Temporary Security Credentials for SAML Federation.
SAML Providers in Using IAM.
Configuring a Relying Party and Claims in Using IAM.
- Creating a Role for SAML-Based Federation in Using IAM.
Specs:
- assume_role_with_saml!(client :: ExAws.Sts.t, input :: assume_role_with_saml_request) :: ExAws.Request.Query.success_t | no_return
Same as assume_role_with_saml/2
but raise on error.
Specs:
- assume_role_with_web_identity(client :: ExAws.Sts.t, input :: assume_role_with_web_identity_request) :: ExAws.Request.Query.response_t
AssumeRoleWithWebIdentity
Returns a set of temporary security credentials for users who have been authenticated in a mobile or web application with a web identity provider, such as Amazon Cognito, Login with Amazon, Facebook, Google, or any OpenID Connect-compatible identity provider.
Note: For mobile applications, we recommend that you use Amazon Cognito. You can use Amazon Cognito with the AWS SDK for iOS and the AWS SDK for Android to uniquely identify a user and supply the user with a consistent identity throughout the lifetime of an application.
To learn more about Amazon Cognito, see Amazon Cognito Overview in the AWS SDK for Android Developer Guide guide and Amazon Cognito Overview in the AWS SDK for iOS Developer Guide.
Calling AssumeRoleWithWebIdentity
does not require the use of AWS
security credentials. Therefore, you can distribute an application (for
example, on mobile devices) that requests temporary security credentials
without including long-term AWS credentials in the application, and without
deploying server-based proxy services that use long-term AWS credentials.
Instead, the identity of the caller is validated by using a token from the
web identity provider.
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 AWS service APIs.
The credentials are valid for the duration that you specified when calling
AssumeRoleWithWebIdentity
, which can be from 900 seconds (15 minutes) to
3600 seconds (1 hour). By default, the temporary security credentials are
valid for 1 hour.
Optionally, you can pass an IAM access policy to this operation. If you choose not to pass a policy, the temporary security credentials that are returned by the operation have the permissions that are defined in the access policy of the role that is being assumed. If you pass a policy to this operation, the temporary security credentials that are returned by the operation have the permissions that are allowed by both the access policy of the role that is being assumed, and the policy that you pass. This gives you a way to further restrict the permissions for the resulting temporary security credentials. You cannot use the passed policy to grant permissions that are in excess of those allowed by the access policy of the role that is being assumed. For more information, see Permissions for AssumeRoleWithWebIdentity.
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.
For more information about how to use web identity federation and the
AssumeRoleWithWebIdentity
API, see the following resources:
Creating a Mobile Application with Third-Party Sign-In and Creating Temporary Security Credentials for Mobile Apps Using Third-Party Identity Providers.
Web Identity Federation Playground. This interactive website lets you walk through the process of authenticating via Login with Amazon, Facebook, or Google, getting temporary security credentials, and then using those credentials to make a request to AWS.
AWS SDK for iOS and AWS SDK for Android. These toolkits contain sample apps that show how to invoke the identity providers, and then 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.
Specs:
- assume_role_with_web_identity!(client :: ExAws.Sts.t, input :: assume_role_with_web_identity_request) :: ExAws.Request.Query.success_t | no_return
Same as assume_role_with_web_identity/2
but raise on error.
Specs:
- decode_authorization_message(client :: ExAws.Sts.t, input :: decode_authorization_message_request) :: ExAws.Request.Query.response_t
DecodeAuthorizationMessage
Decodes additional information about the authorization status of a request from an encoded message returned in response to an AWS request.
For example, if a user is not authorized to perform an action that he or
she has requested, the request returns a Client.UnauthorizedOperation
response (an HTTP 403 response). Some AWS actions additionally return an
encoded message that can provide details about this authorization failure.
Note: Only certain AWS actions return an encoded authorization message. The
documentation for an individual action indicates whether that action
returns an encoded message in addition to returning an HTTP code. The
message is encoded because the details of the authorization status can
constitute privileged information that the user who requested the action
should not see. To decode an authorization status message, a user must be
granted permissions via an IAM policy to request the
DecodeAuthorizationMessage
(sts:DecodeAuthorizationMessage
) action.
The decoded message includes the following type of information:
Whether the request was denied due to an explicit deny or due to the absence of an explicit allow. For more information, see Determining Whether a Request is Allowed or Denied in Using IAM.
The principal who made the request.
The requested action.
The requested resource.
- The values of condition keys in the context of the user’s request.
Specs:
- decode_authorization_message!(client :: ExAws.Sts.t, input :: decode_authorization_message_request) :: ExAws.Request.Query.success_t | no_return
Same as decode_authorization_message/2
but raise on error.
Specs:
- get_federation_token(client :: ExAws.Sts.t, input :: get_federation_token_request) :: ExAws.Request.Query.response_t
GetFederationToken
Returns a set of temporary security credentials (consisting of an access
key ID, a secret access key, and a security token) for a federated user. A
typical use is in a proxy application that gets temporary security
credentials on behalf of distributed applications inside a corporate
network. Because you must call the GetFederationToken
action using the
long-term security credentials of an IAM user, this call is appropriate in
contexts where those credentials can be safely stored, usually in a
server-based application.
Note: If you are creating a mobile-based or browser-based app that can
authenticate users using a web identity provider like Login with Amazon,
Facebook, Google, or an OpenID Connect-compatible identity provider, we
recommend that you use Amazon Cognito or
AssumeRoleWithWebIdentity
. For more information, see Creating Temporary
Security Credentials for Mobile Apps Using Identity
Providers.
The GetFederationToken
action must be called by using the long-term AWS
security credentials of an IAM user. You can also call GetFederationToken
using the security credentials of an AWS account (root), but this is not
recommended. Instead, we recommend that you create an IAM user for the
purpose of the proxy application and then attach a policy to the IAM user
that limits federated users to only the actions and resources they need
access to. For more information, see IAM Best
Practices
in Using IAM.
The temporary security credentials that are obtained by using the long-term credentials of an IAM user are valid for the specified duration, between 900 seconds (15 minutes) and 129600 seconds (36 hours). Temporary credentials that are obtained by using AWS account (root) credentials have a maximum duration of 3600 seconds (1 hour)
Permissions
The permissions for the temporary security credentials returned by
GetFederationToken
are determined by a combination of the following:
The policy or policies that are attached to the IAM user whose credentials are used to call
GetFederationToken
.- The policy that is passed as a parameter in the call.
The passed policy is attached to the temporary security credentials that
result from the GetFederationToken
API call—that is, to the federated
user. When the federated user makes an AWS request, AWS evaluates the
policy attached to the federated user in combination with the policy or
policies attached to the IAM user whose credentials were used to call
GetFederationToken
. AWS allows the federated user’s request only when
both the federated user and the IAM user are explicitly allowed to
perform the requested action. The passed policy cannot grant more
permissions than those that are defined in the IAM user policy.
A typical use case is that the permissions of the IAM user whose
credentials are used to call GetFederationToken
are designed to allow
access to all the actions and resources that any federated user will need.
Then, for individual users, you pass a policy to the operation that scopes
down the permissions to a level that’s appropriate to that individual user,
using a policy that allows only a subset of permissions that are granted to
the IAM user.
If you do not pass a policy, the resulting temporary security credentials have no effective permissions. The only exception is when the temporary security credentials are used to access a resource that has a resource-based policy that specifically allows the federated user to access the resource.
For more information about how permissions work, see Permissions for
GetFederationToken.
For information about using GetFederationToken
to create temporary
security credentials, see Creating Temporary Credentials to Enable Access
for Federated
Users.
Specs:
- get_federation_token!(client :: ExAws.Sts.t, input :: get_federation_token_request) :: ExAws.Request.Query.success_t | no_return
Same as get_federation_token/2
but raise on error.
Specs:
- get_session_token(client :: ExAws.Sts.t, input :: get_session_token_request) :: ExAws.Request.Query.response_t
GetSessionToken
Returns a set of temporary credentials for an AWS account or IAM user. The
credentials consist of an access key ID, a secret access key, and a
security token. Typically, you use GetSessionToken
if you want to use MFA
to protect programmatic calls to specific AWS APIs like Amazon EC2
StopInstances
. MFA-enabled IAM users would need to call GetSessionToken
and submit an MFA code that is associated with their MFA device. Using the
temporary security credentials that are returned from the call, IAM users
can then make programmatic calls to APIs that require MFA authentication.
The GetSessionToken
action must be called by using the long-term AWS
security credentials of the AWS account or an IAM user. Credentials that
are created by IAM users are valid for the duration that you specify,
between 900 seconds (15 minutes) and 129600 seconds (36 hours); credentials
that are created by using account credentials have a maximum duration of
3600 seconds (1 hour).
Note: We recommend that you do not call GetSessionToken
with root account
credentials. Instead, follow our best
practices
by creating one or more IAM users, giving them the necessary permissions,
and using IAM users for everyday interaction with AWS.
The permissions associated with the temporary security credentials returned
by GetSessionToken
are based on the permissions associated with account
or IAM user whose credentials are used to call the action. If
GetSessionToken
is called using root account credentials, the temporary
credentials have root account permissions. Similarly, if GetSessionToken
is called using the credentials of an IAM user, the temporary credentials
have the same permissions as the IAM user.
For more information about using GetSessionToken
to create temporary
credentials, go to Creating Temporary Credentials to Enable Access for IAM
Users.
Specs:
- get_session_token!(client :: ExAws.Sts.t, input :: get_session_token_request) :: ExAws.Request.Query.success_t | no_return
Same as get_session_token/2
but raise on error.