STS / Client / get_federation_token

get_federation_token#

STS.Client.get_federation_token(**kwargs)#

Returns a set of temporary security credentials (consisting of an access key ID, a secret access key, and a security token) for a user. A typical use is in a proxy application that gets temporary security credentials on behalf of distributed applications inside a corporate network.

You must call the GetFederationToken operation using the long-term security credentials of an IAM user. As a result, this call is appropriate in contexts where those credentials can be safeguarded, usually in a server-based application. For a comparison of GetFederationToken with the other API operations that produce temporary credentials, see Requesting Temporary Security Credentials and Compare STS credentials in the IAM User Guide.

Although it is possible to call GetFederationToken using the security credentials of an Amazon Web Services account root user rather than an IAM user that you create for the purpose of a proxy application, we do not recommend it. For more information, see Safeguard your root user credentials and don’t use them for everyday tasks in the IAM User Guide.

Note

You can create 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. In this case, we recommend that you use Amazon Cognito or AssumeRoleWithWebIdentity. For more information, see Federation Through a Web-based Identity Provider in the IAM User Guide.

Session duration

The temporary credentials are valid for the specified duration, from 900 seconds (15 minutes) up to a maximum of 129,600 seconds (36 hours). The default session duration is 43,200 seconds (12 hours). Temporary credentials obtained by using the root user credentials have a maximum duration of 3,600 seconds (1 hour).

Permissions

You can use the temporary credentials created by GetFederationToken in any Amazon Web Services service with the following exceptions:

You cannot call any IAM operations using the CLI or the Amazon Web Services API. This limitation does not apply to console sessions.
You cannot call any STS operations except GetCallerIdentity.

You can use temporary credentials for single sign-on (SSO) to the console.

You must pass an inline or managed session policy 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 policy Amazon Resource Names (ARNs) to use as managed session policies. The plaintext that you use for both inline and managed session policies can’t exceed 2,048 characters.

Though the session policy parameters are optional, if you do not pass a policy, then the resulting federated user session has no permissions. When you pass session policies, the session permissions are the intersection of the IAM user policies and the session policies that you pass. This gives you a way to further restrict the permissions for a federated user. You cannot use session policies to grant more permissions than those that are defined in the permissions policy of the IAM user. For more information, see Session Policies in the IAM User Guide. For information about using GetFederationToken to create temporary security credentials, see GetFederationToken—Federation Through a Custom Identity Broker.

You can use the credentials to access a resource that has a resource-based policy. If that policy specifically references the federated user session in the Principal element of the policy, the session has the permissions allowed by the policy. These permissions are granted in addition to the permissions granted by the session policies.

Note

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.

Tag key–value pairs are not case sensitive, but case is preserved. This means that you cannot have separate Department and department tag keys. Assume that the user that you are federating has the Department``= ``Marketing tag and you pass the department``= ``engineering session tag. Department and department are not saved as separate tags, and the session tag passed in the request takes precedence over the user tag.

Request Syntax

response = client.get_federation_token(
    Name='string',
    Policy='string',
    PolicyArns=[
        {
            'arn': 'string'
        },
    ],
    DurationSeconds=123,
    Tags=[
        {
            'Key': 'string',
            'Value': 'string'
        },
    ]
)

Parameters:

Name (string) –
[REQUIRED]

The name of the federated user. The name is used as an identifier for the temporary security credentials (such as Bob). For example, you can reference the federated user name in a resource-based policy, such as in an Amazon S3 bucket policy.

The regex used to validate this parameter is a string of characters consisting of upper- and lower-case alphanumeric characters with no spaces. You can also include underscores or any of the following characters: =,.@-
Policy (string) –
An IAM policy in JSON format that you want to use as an inline session policy.

You must pass an inline or managed session policy 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 policy Amazon Resource Names (ARNs) to use as managed session policies.

This parameter is optional. However, if you do not pass any session policies, then the resulting federated user session has no permissions.

When you pass session policies, the session permissions are the intersection of the IAM user policies and the session policies that you pass. This gives you a way to further restrict the permissions for a federated user. You cannot use session policies to grant more permissions than those that are defined in the permissions policy of the IAM user. For more information, see Session Policies in the IAM User Guide.

The resulting credentials can be used to access a resource that has a resource-based policy. If that policy specifically references the federated user session in the Principal element of the policy, the session has the permissions allowed by the policy. These permissions are granted in addition to the permissions that are granted by the session policies.

The plaintext that you use for both inline and managed session policies can’t exceed 2,048 characters. The JSON policy characters can be any ASCII character from the space character to the end of the valid character list (u0020 through u00FF). It can also include the tab (u0009), linefeed (u000A), and carriage return (u000D) characters.

Note
An Amazon Web Services conversion compresses the passed inline session policy, managed policy ARNs, 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 PackedPolicySize response element indicates by percentage how close the policies and tags for your request are to the upper size limit.
PolicyArns (list) –
The Amazon Resource Names (ARNs) of the IAM managed policies that you want to use as a managed session policy. The policies must exist in the same account as the IAM user that is requesting federated access.

You must pass an inline or managed session policy 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 policy Amazon Resource Names (ARNs) to use as managed session policies. The plaintext that you use for both inline and managed session policies can’t exceed 2,048 characters. You can provide up to 10 managed policy ARNs. For more information about ARNs, see Amazon Resource Names (ARNs) and Amazon Web Services Service Namespaces in the Amazon Web Services General Reference.

This parameter is optional. However, if you do not pass any session policies, then the resulting federated user session has no permissions.

When you pass session policies, the session permissions are the intersection of the IAM user policies and the session policies that you pass. This gives you a way to further restrict the permissions for a federated user. You cannot use session policies to grant more permissions than those that are defined in the permissions policy of the IAM user. For more information, see Session Policies in the IAM User Guide.

The resulting credentials can be used to access a resource that has a resource-based policy. If that policy specifically references the federated user session in the Principal element of the policy, the session has the permissions allowed by the policy. These permissions are granted in addition to the permissions that are granted by the session policies.

Note
An Amazon Web Services conversion compresses the passed inline session policy, managed policy ARNs, 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 PackedPolicySize response element indicates by percentage how close the policies and tags for your request are to the upper size limit.
- (dict) –
  
  A reference to the IAM managed policy that is passed as a session policy for a role session or a federated user session.
  - arn (string) –
    
    The Amazon Resource Name (ARN) of the IAM managed policy to use as a session policy for the role. For more information about ARNs, see Amazon Resource Names (ARNs) and Amazon Web Services Service Namespaces in the Amazon Web Services General Reference.
DurationSeconds (integer) – The duration, in seconds, that the session should last. Acceptable durations for federation sessions range from 900 seconds (15 minutes) to 129,600 seconds (36 hours), with 43,200 seconds (12 hours) as the default. Sessions obtained using root user credentials are restricted to a maximum of 3,600 seconds (one hour). If the specified duration is longer than one hour, the session obtained by using root user credentials defaults to one hour.
Tags (list) –
A list of 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.

This parameter is optional. 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.

Note
An Amazon Web Services conversion compresses the passed inline session policy, managed policy ARNs, 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 PackedPolicySize 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 already attached to the user you are federating. When you do, session tags override a user tag with the same key.

Tag key–value pairs are not case sensitive, but case is preserved. This means that you cannot have separate Department and department tag keys. Assume that the role has the Department``= ``Marketing tag and you pass the department``= ``engineering session tag. Department and department are not saved as separate tags, and the session tag passed in the request takes precedence over the role tag.
- (dict) –
  
  You can pass custom key-value pair attributes when you assume a role or federate a user. These are called session tags. You can then use the session tags to control access to resources. For more information, see Tagging Amazon Web Services STS Sessions in the IAM User Guide.
  - Key (string) – [REQUIRED]
    
    The key for a session tag.
    
    You can pass up to 50 session tags. The plain text session tag keys can’t exceed 128 characters. For these and additional limits, see IAM and STS Character Limits in the IAM User Guide.
  - Value (string) – [REQUIRED]
    
    The value for a session tag.
    
    You can pass up to 50 session tags. The plain text session tag values can’t exceed 256 characters. For these and additional limits, see IAM and STS Character Limits in the IAM User Guide.

Return type:

dict

Returns:

Response Syntax

{
    'Credentials': {
        'AccessKeyId': 'string',
        'SecretAccessKey': 'string',
        'SessionToken': 'string',
        'Expiration': datetime(2015, 1, 1)
    },
    'FederatedUser': {
        'FederatedUserId': 'string',
        'Arn': 'string'
    },
    'PackedPolicySize': 123
}

Response Structure

(dict) –

Contains the response to a successful GetFederationToken request, including temporary Amazon Web Services credentials that can be used to make Amazon Web Services requests.
- Credentials (dict) –
  
  The temporary security credentials, which include an access key ID, a secret access key, and a security (or session) token.
  
  Note
  The size of the security token that STS API operations return is not fixed. We strongly recommend that you make no assumptions about the maximum size.
  - AccessKeyId (string) –
    
    The access key ID that identifies the temporary security credentials.
  - SecretAccessKey (string) –
    
    The secret access key that can be used to sign requests.
  - SessionToken (string) –
    
    The token that users must pass to the service API to use the temporary credentials.
  - Expiration (datetime) –
    
    The date on which the current credentials expire.
- FederatedUser (dict) –
  
  Identifiers for the federated user associated with the credentials (such as arn:aws:sts::123456789012:federated-user/Bob or 123456789012:Bob). You can use the federated user’s ARN in your resource-based policies, such as an Amazon S3 bucket policy.
  - FederatedUserId (string) –
    
    The string that identifies the federated user associated with the credentials, similar to the unique ID of an IAM user.
  - Arn (string) –
    
    The ARN that specifies the federated user that is associated with the credentials. For more information about ARNs and how to use them in policies, see IAM Identifiers in the IAM User Guide.
- PackedPolicySize (integer) –
  
  A percentage value that indicates the packed size of the session policies and session tags combined passed in the request. The request fails if the packed size is greater than 100 percent, which means the policies and tags exceeded the allowed space.

Exceptions

STS.Client.exceptions.MalformedPolicyDocumentException
STS.Client.exceptions.PackedPolicyTooLargeException
STS.Client.exceptions.RegionDisabledException

Examples

response = client.get_federation_token(
    DurationSeconds=3600,
    Name='testFedUserSession',
    Policy='{"Version":"2012-10-17","Statement":[{"Sid":"Stmt1","Effect":"Allow","Action":"s3:ListAllMyBuckets","Resource":"*"}]}',
    Tags=[
        {
            'Key': 'Project',
            'Value': 'Pegasus',
        },
        {
            'Key': 'Cost-Center',
            'Value': '98765',
        },
    ],
)

print(response)

Expected Output:

{
    'Credentials': {
        'AccessKeyId': 'AKIAIOSFODNN7EXAMPLE',
        'Expiration': datetime(2011, 7, 15, 23, 28, 33, 4, 196, 0),
        'SecretAccessKey': 'wJalrXUtnFEMI/K7MDENG/bPxRfiCYzEXAMPLEKEY',
        'SessionToken': 'AQoDYXdzEPT//////////wEXAMPLEtc764bNrC9SAPBSM22wDOk4x4HIZ8j4FZTwdQWLWsKWHGBuFqwAeMicRXmxfpSPfIeoIYRqTflfKD8YUuwthAx7mSEI/qkPpKPi/kMcGdQrmGdeehM4IC1NtBmUpp2wUE8phUZampKsburEDy0KPkyQDYwT7WZ0wq5VSXDvp75YU9HFvlRd8Tx6q6fE8YQcHNVXAkiY9q6d+xo0rKwT38xVqr7ZD0u0iPPkUL64lIZbqBAz+scqKmlzm8FDrypNC9Yjc8fPOLn9FX9KSYvKTr4rvx3iSIlTJabIQwj2ICCR/oLxBA==',
    },
    'FederatedUser': {
        'Arn': 'arn:aws:sts::123456789012:federated-user/Bob',
        'FederatedUserId': '123456789012:Bob',
    },
    'PackedPolicySize': 8,
    'ResponseMetadata': {
        '...': '...',
    },
}