2021/04/13 - AWS Security Token Service - 3 updated api methods
Changes This release adds the SourceIdentity parameter that can be set when assuming a role.
{'SourceIdentity': '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.
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 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 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',
SourceIdentity='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 plaintext 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.
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 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.
integer
The duration, in seconds, of the role session. The value specified can can range from 900 seconds (15 minutes) up to the maximum session duration that is set for the role. The maximum session duration setting can have a value from 1 hour to 12 hours. If you specify a value higher than this setting or the administrator setting (whichever is lower), 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.
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 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.
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. (In other words, 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.
string
The source identity specified by the principal that is calling the AssumeRole operation.
You can require users to specify a source identity when they assume a role. You do this by using the sts:SourceIdentity condition key in a role trust policy. You can use source identity information in AWS CloudTrail logs to determine who took actions with a role. You can use the aws:SourceIdentity condition key to further control access to AWS resources based on the value of source identity. For more information about using source identity, see Monitor and control actions taken with assumed roles 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: =,.@-. You cannot use a value that begins with the text aws:. This prefix is reserved for AWS internal use.
dict
Response Syntax
{
'Credentials': {
'AccessKeyId': 'string',
'SecretAccessKey': 'string',
'SessionToken': 'string',
'Expiration': datetime(2015, 1, 1)
},
'AssumedRoleUser': {
'AssumedRoleId': 'string',
'Arn': 'string'
},
'PackedPolicySize': 123,
'SourceIdentity': 'string'
}
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.
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.
SourceIdentity (string) --
The source identity specified by the principal that is calling the AssumeRole operation.
You can require users to specify a source identity when they assume a role. You do this by using the sts:SourceIdentity condition key in a role trust policy. You can use source identity information in AWS CloudTrail logs to determine who took actions with a role. You can use the aws:SourceIdentity condition key to further control access to AWS resources based on the value of source identity. For more information about using source identity, see Monitor and control actions taken with assumed roles 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: =,.@-
{'SourceIdentity': 'string'}
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. For a comparison of AssumeRoleWithSAML 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.
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.
Session Duration
By default, the temporary security credentials created by AssumeRoleWithSAML last for one hour. However, you can use the optional DurationSeconds parameter to specify the duration of your session. Your role session lasts for the duration that you specify, or until the time specified in the SAML authentication response's SessionNotOnOrAfter value, whichever is shorter. You can provide a DurationSeconds 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 AssumeRoleWithSAML can be used to make API calls to any AWS service with the following exception: you cannot call the 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 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 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.
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.
Tags
(Optional) You can configure your IdP to pass attributes into your SAML assertion 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.
You can pass a session tag with the same key as a tag that is attached to the role. When you do, session tags override the role's tags 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.
SAML Configuration
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. You must also create an IAM role that specifies this SAML provider in its trust policy.
For more information, see the following resources:
About SAML 2.0-based Federation in the IAM User Guide.
Creating SAML Identity Providers in the IAM User Guide.
Configuring a Relying Party and Claims in the IAM User Guide.
Creating a Role for SAML 2.0 Federation in the IAM User Guide.
See also: AWS API Documentation
Request Syntax
client.assume_role_with_saml(
RoleArn='string',
PrincipalArn='string',
SAMLAssertion='string',
PolicyArns=[
{
'arn': 'string'
},
],
Policy='string',
DurationSeconds=123
)
string
[REQUIRED]
The Amazon Resource Name (ARN) of the role that the caller is assuming.
string
[REQUIRED]
The Amazon Resource Name (ARN) of the SAML provider in IAM that describes the IdP.
string
[REQUIRED]
The base64 encoded SAML authentication response provided by the IdP.
For more information, see Configuring a Relying Party and Adding Claims in the IAM User Guide.
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 plaintext 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.
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 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.
integer
The duration, in seconds, of the role session. Your role session lasts for the duration that you specify for the DurationSeconds parameter, or until the time specified in the SAML authentication response's SessionNotOnOrAfter value, whichever is shorter. You can provide a DurationSeconds 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. 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.
dict
Response Syntax
{
'Credentials': {
'AccessKeyId': 'string',
'SecretAccessKey': 'string',
'SessionToken': 'string',
'Expiration': datetime(2015, 1, 1)
},
'AssumedRoleUser': {
'AssumedRoleId': 'string',
'Arn': 'string'
},
'PackedPolicySize': 123,
'Subject': 'string',
'SubjectType': 'string',
'Issuer': 'string',
'Audience': 'string',
'NameQualifier': 'string',
'SourceIdentity': 'string'
}
Response Structure
(dict) --
Contains the response to a successful AssumeRoleWithSAML 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.
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 identifiers for the temporary security credentials that the operation returns.
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.
Subject (string) --
The value of the NameID element in the Subject element of the SAML assertion.
SubjectType (string) --
The format of the name ID, as defined by the Format attribute in the NameID element of the SAML assertion. Typical examples of the format are transient or persistent.
If the format includes the prefix urn:oasis:names:tc:SAML:2.0:nameid-format, that prefix is removed. For example, urn:oasis:names:tc:SAML:2.0:nameid-format:transient is returned as transient. If the format includes any other prefix, the format is returned with no modifications.
Issuer (string) --
The value of the Issuer element of the SAML assertion.
Audience (string) --
The value of the Recipient attribute of the SubjectConfirmationData element of the SAML assertion.
NameQualifier (string) --
A hash value based on the concatenation of the following:
The Issuer response value.
The AWS account ID.
The friendly name (the last part of the ARN) of the SAML provider in IAM.
The combination of NameQualifier and Subject can be used to uniquely identify a federated user.
The following pseudocode shows how the hash value is calculated:
BASE64 ( SHA1 ( "https://example.com/saml" + "123456789012" + "/MySAMLIdP" ) )
SourceIdentity (string) --
The value in the SourceIdentity attribute in the SAML assertion.
You can require users to set a source identity value when they assume a role. You do this by using the sts:SourceIdentity condition key in a role trust policy. That way, actions that are taken with the role are associated with that user. After the source identity is set, the value cannot be changed. It is present in the request for all actions that are taken by the role and persists across chained role sessions. You can configure your SAML identity provider to use an attribute associated with your users, like user name or email, as the source identity when calling AssumeRoleWithSAML. You do this by adding an attribute to the SAML assertion. For more information about using source identity, see Monitor and control actions taken with assumed roles 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: =,.@-
{'SourceIdentity': 'string'}
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.
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. You also don't need to deploy 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. For a comparison of AssumeRoleWithWebIdentity 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.
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 API operations.
Session Duration
By default, the temporary security credentials created by AssumeRoleWithWebIdentity 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 AssumeRoleWithWebIdentity can be used to make API calls to any AWS service with the following exception: you cannot call the 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 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 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.
Tags
(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.
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.
Identities
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:
Using Web Identity Federation API Operations for Mobile Apps and Federation Through a Web-based Identity Provider.
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 AWS.
AWS SDK for iOS Developer Guide and AWS 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.
See also: AWS API Documentation
Request Syntax
client.assume_role_with_web_identity(
RoleArn='string',
RoleSessionName='string',
WebIdentityToken='string',
ProviderId='string',
PolicyArns=[
{
'arn': 'string'
},
],
Policy='string',
DurationSeconds=123
)
string
[REQUIRED]
The Amazon Resource Name (ARN) of the role that the caller is assuming.
string
[REQUIRED]
An identifier for the assumed role session. Typically, you pass the name or identifier that is associated with the user who is using your application. That way, the temporary security credentials that your application will use are associated with that user. This session name is included as part of the ARN and assumed role ID in the AssumedRoleUser response element.
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
[REQUIRED]
The OAuth 2.0 access token or OpenID Connect ID token that is provided by the identity provider. Your application must get this token by authenticating the user who is using your application with a web identity provider before the application makes an AssumeRoleWithWebIdentity call.
string
The fully qualified host component of the domain name of the identity provider.
Specify this value only for OAuth 2.0 access tokens. Currently www.amazon.com and graph.facebook.com are the only supported identity providers for OAuth 2.0 access tokens. Do not include URL schemes and port numbers.
Do not specify this value for OpenID Connect ID tokens.
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 plaintext 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.
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 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.
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.
dict
Response Syntax
{
'Credentials': {
'AccessKeyId': 'string',
'SecretAccessKey': 'string',
'SessionToken': 'string',
'Expiration': datetime(2015, 1, 1)
},
'SubjectFromWebIdentityToken': 'string',
'AssumedRoleUser': {
'AssumedRoleId': 'string',
'Arn': 'string'
},
'PackedPolicySize': 123,
'Provider': 'string',
'Audience': 'string',
'SourceIdentity': 'string'
}
Response Structure
(dict) --
Contains the response to a successful AssumeRoleWithWebIdentity 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 token.
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.
SubjectFromWebIdentityToken (string) --
The unique user identifier that is returned by the identity provider. This identifier is associated with the WebIdentityToken that was submitted with the AssumeRoleWithWebIdentity call. The identifier is typically unique to the user and the application that acquired the WebIdentityToken (pairwise identifier). For OpenID Connect ID tokens, this field contains the value returned by the identity provider as the token's sub (Subject) claim.
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.
Provider (string) --
The issuing authority of the web identity token presented. For OpenID Connect ID tokens, this contains the value of the iss field. For OAuth 2.0 access tokens, this contains the value of the ProviderId parameter that was passed in the AssumeRoleWithWebIdentity request.
Audience (string) --
The intended audience (also known as client ID) of the web identity token. This is traditionally the client identifier issued to the application that requested the web identity token.
SourceIdentity (string) --
The value of the source identity that is returned in the JSON web token (JWT) from the identity provider.
You can require users to set a source identity value when they assume a role. You do this by using the sts:SourceIdentity condition key in a role trust policy. That way, actions that are taken with the role are associated with that user. After the source identity is set, the value cannot be changed. It is present in the request for all actions that are taken by the role and persists across chained role sessions. You can configure your identity provider to use an attribute associated with your users, like user name or email, as the source identity when calling AssumeRoleWithWebIdentity. You do this by adding a claim to the JSON web token. To learn more about OIDC tokens and claims, see Using Tokens with User Pools in the Amazon Cognito Developer Guide. For more information about using source identity, see Monitor and control actions taken with assumed roles 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: =,.@-