2019/11/22 - AWS Security Token Service - 2 updated api methods
Changes Support tagging for STS sessions and tag based access control for the STS APIs
{'Tags': [{'Key': 'string', 'Value': 'string'}],
'TransitiveTagKeys': ['string']}
Returns a set of temporary security credentials that you can use to access AWS resources that you might not normally have access to. These temporary credentials consist of an access key ID, a secret access key, and a security token. Typically, you use AssumeRole within your account or for cross-account access. For a comparison of AssumeRole with other API operations that produce temporary credentials, see Requesting Temporary Security Credentials and Comparing the AWS STS API operations in the IAM User Guide .
Warning
You cannot use AWS account root user credentials to call AssumeRole . You must use credentials for an IAM user or an IAM role 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. 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 in the IAM User Guide .
Session Duration
By default, the temporary security credentials created by AssumeRole last for one hour. However, you can use the optional 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 assume-role* CLI 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 .
Permissions
The temporary security credentials created by AssumeRole can be used to make API calls to any AWS service with the following exception: You cannot call the AWS STS GetFederationToken or GetSessionToken API operations.
(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 plain text 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 AWS 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 .
To assume a role from a different account, 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. That trust policy states which accounts are allowed to delegate that access to users in the account.
A user who wants to access a role in a different account must also have permissions that are delegated from the user account administrator. The administrator must attach a policy that allows the user to call AssumeRole for the ARN of the role in the other account. If the user is in the same account as the role, then you can do either of the following:
Attach a policy to the user (identical to the previous user in a different account).
Add the user as a principal directly in the role's trust policy.
In this case, the trust policy acts as an IAM resource-based policy. Users in the same account as the role do not need explicit permission to assume the role. For more information about trust policies and resource-based policies, see IAM Policies in the IAM User Guide .
Tags
(Optional) You can pass tag key-value pairs to your session. These tags are called session tags. For more information about session tags, see Passing Session Tags in STS in the IAM User Guide .
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 .
Using MFA with AssumeRole
(Optional) You can include multi-factor authentication (MFA) information when you call AssumeRole . This is useful for cross-account scenarios to ensure that the user that assumes the role has been authenticated with 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 the IAM User Guide 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 device produces.
See also: AWS API Documentation
Request Syntax
client.assume_role(
RoleArn='string',
RoleSessionName='string',
PolicyArns=[
{
'arn': 'string'
},
],
Policy='string',
DurationSeconds=123,
Tags=[
{
'Key': 'string',
'Value': 'string'
},
],
TransitiveTagKeys=[
'string',
],
ExternalId='string',
SerialNumber='string',
TokenCode='string'
)
string
[REQUIRED]
The Amazon Resource Name (ARN) of the role to assume.
string
[REQUIRED]
An identifier for the assumed role session.
Use the role session name to uniquely identify a session when the same role is assumed by different principals or for different reasons. In cross-account scenarios, the role session name is visible to, and can be logged by the account that owns the role. The role session name is also used in the ARN of the assumed role principal. This means that subsequent cross-account API requests that use the temporary security credentials will expose the role session name to the external account in their AWS CloudTrail logs.
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: =,.@-
list
The Amazon Resource Names (ARNs) of the IAM managed policies that you want to use as managed session policies. The policies must exist in the same account as the role.
This parameter is optional. You can provide up to 10 managed policy ARNs. However, the plain text that you use for both inline and managed session policies can't exceed 2,048 characters. For more information about ARNs, see Amazon Resource Names (ARNs) and AWS Service Namespaces in the AWS General Reference.
Note
An AWS 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 plain text 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.
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 AWS 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 .
(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 AWS Service Namespaces in the AWS General Reference .
string
An IAM policy in JSON format that you want to use as an inline session policy.
This parameter is optional. 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 AWS 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 .
The plain text 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 AWS 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 plain text 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.
integer
The duration, in seconds, of the role session. The value can range 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. If you specify a value higher than this setting, the operation fails. For example, if you specify a session duration of 12 hours, but your administrator set the maximum session duration to 6 hours, your operation fails. 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 .
By default, the value is set to 3600 seconds.
Note
The DurationSeconds parameter is separate from the duration of a console session that you might request using the returned credentials. The request to the federation endpoint for a console sign-in token takes a SessionDuration parameter that specifies the maximum length of the console session. For more information, see Creating a URL that Enables Federated Users to Access the AWS Management Console in the IAM User Guide .
list
A list of session tags that you want to pass. Each session tag consists of a key name and an associated value. For more information about session tags, see Tagging AWS STS Sessions in the IAM User Guide .
This parameter is optional. You can pass up to 50 session tags. The plain text 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 AWS 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 plain text 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 role. When you do, session tags override a role 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.
Additionally, if you used temporary credentials to perform this operation, the new session inherits any transitive session tags from the calling session. If you pass a session tag with the same key as an inherited tag, the operation fails. To view the inherited tags for a session, see the AWS CloudTrail logs. For more information, see Viewing Session Tags in CloudTrail in the IAM User Guide .
(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 AWS 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 .
list
A list of keys for session tags that you want to set as transitive. If you set a tag key as transitive, the corresponding key and value passes to subsequent sessions in a role chain. For more information, see Chaining Roles with Session Tags in the IAM User Guide .
This parameter is optional. When you set session tags as transitive, the session policy and session tags packed binary limit is not affected.
If you choose not to specify a transitive tag key, then no tags are passed from this session to any subsequent sessions.
(string) --
string
A unique identifier that might be required when you assume a role in another account. If the administrator of the account to which the role belongs provided you with an external ID, then provide that value in the ExternalId parameter. This value can be any string, such as a passphrase or account number. A cross-account role is usually set up to trust everyone in an account. Therefore, the administrator of the trusting account might send an external ID to the administrator of the trusted account. That way, only someone with the ID can assume the role, rather than everyone in the account. For more information about the external ID, see How to Use an External ID When Granting Access to Your AWS Resources to a Third Party in the IAM User Guide .
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: =,.@:/-
string
The identification number of the MFA device that is associated with the user who is making the AssumeRole call. Specify this value if the trust policy of the role being assumed includes a condition that requires MFA authentication. The value is either the serial number for a hardware device (such as GAHT12345678 ) or an Amazon Resource Name (ARN) for a virtual device (such as arn:aws:iam::123456789012:mfa/user ).
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: =,.@-
string
The value provided by the MFA device, if the trust policy of the role being assumed requires MFA (that is, if the policy includes a condition that tests for MFA). If the role being assumed requires MFA and if the TokenCode value is missing or expired, the AssumeRole call returns an "access denied" error.
The format for this parameter, as described by its regex pattern, is a sequence of six numeric digits.
dict
Response Syntax
{
'Credentials': {
'AccessKeyId': 'string',
'SecretAccessKey': 'string',
'SessionToken': 'string',
'Expiration': datetime(2015, 1, 1)
},
'AssumedRoleUser': {
'AssumedRoleId': 'string',
'Arn': 'string'
},
'PackedPolicySize': 123
}
Response Structure
(dict) --
Contains the response to a successful AssumeRole request, including temporary AWS credentials that can be used to make AWS 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.
AssumedRoleUser (dict) --
The Amazon Resource Name (ARN) and the assumed role ID, which are identifiers that you can use to refer to the resulting temporary security credentials. For example, you can reference these credentials as a principal in a resource-based policy by using the ARN or assumed role ID. The ARN and ID include the RoleSessionName that you specified when you called AssumeRole .
AssumedRoleId (string) --
A unique identifier that contains the role ID and the role session name of the role that is being assumed. The role ID is generated by AWS when the role is created.
Arn (string) --
The ARN of the temporary security credentials that are returned from the AssumeRole action. 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.
{'Tags': [{'Key': 'string', 'Value': 'string'}]}
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. 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 safely stored, 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 Comparing the AWS STS API operations 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 .
You can also call GetFederationToken using the security credentials of an AWS account root user, but we do not recommend it. Instead, we recommend that you create an IAM user for the purpose of the proxy application. Then attach a policy to the IAM user that limits federated users to only the actions and resources that they need to access. For more information, see IAM Best Practices 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 that are obtained by using AWS account 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 AWS service except the following:
You cannot call any IAM operations using the AWS CLI or the AWS API.
You cannot call any STS operations except GetCallerIdentity .
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 policies to use as managed session policies. The plain text 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.
Tags
(Optional) You can pass tag key-value pairs to your session. These are called session tags. For more information about session tags, see Passing Session Tags in STS in the IAM User Guide .
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.
See also: AWS API Documentation
Request Syntax
client.get_federation_token(
Name='string',
Policy='string',
PolicyArns=[
{
'arn': 'string'
},
],
DurationSeconds=123,
Tags=[
{
'Key': 'string',
'Value': 'string'
},
]
)
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: =,.@-
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 policies 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 plain text 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 AWS 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 plain text 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.
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 policies to use as managed session policies. The plain text 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 AWS Service Namespaces in the AWS 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 AWS 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 plain text 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 AWS Service Namespaces in the AWS General Reference .
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 AWS account 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.
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 plain text 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 AWS 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 plain text 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 AWS 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 .
dict
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 AWS credentials that can be used to make AWS 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.