AssumeRole - Resource Access Management

Obtains a Security Token Service (STS) token to assume a Resource Access Management (RAM) role.

Operation description

Prerequisites

You cannot use an Alibaba Cloud account to call this operation. The requester of this operation can only be a RAM user or RAM role. Make sure that the AliyunSTSAssumeRoleAccess policy is attached to the requester. After this policy is attached to the requester, the requester has the management permissions on STS.

If you do not attach the AliyunSTSAssumeRoleAccess policy to the requester, the following error message is returned:

You are not authorized to do this action. You should be authorized by RAM.

You can refer to the following information to troubleshoot the error:

Cause of the error: The policy that is required to assume a RAM role is not attached to the requester. To resolve this issue, attach the AliyunSTSAssumeRoleAccess policy or a custom policy to the requester. For more information, see Can I specify the RAM role that a RAM user can assume? and Grant permissions to a RAM user.
Cause of the error: The requester is not authorized to assume the RAM role. To resolve this issue, add the requester to the Principal element in the trust policy of the RAM role For more information, see Edit the trust policy of a RAM role.

Best practices

An STS token is valid for a period of time after it is issued, and the number of STS tokens that can be issued within an interval is also limited. Therefore, we recommend that you configure a proper validity period for an STS token and repeatedly use the token within this period. This prevents frequent issuing of STS tokens from adversely affecting your services if a large number of requests are sent. For more information about the limit, see Is the number of STS API requests limited? You can configure the DurationSeconds parameter to specify a validity period for an STS token.

When you upload or download Object Storage Service (OSS) objects on mobile devices, a large number of STS API requests are sent. In this case, repeated use of an STS token may not meet your business requirements. To avoid the limit on STS API requests from affecting access to OSS, you can add a signature to the URL of an OSS object. For more information, see Add signatures to URLs and Obtain signature information from the server and upload data to OSS.

Debugging

OpenAPI Explorer automatically calculates the signature value. For your convenience, we recommend that you call this operation in OpenAPI Explorer.

Debug

Authorization information

The following table shows the authorization information corresponding to the API. The authorization information can be used in the Action policy element to grant a RAM user or RAM role the permissions to call this API operation. Description:

Operation: the value that you can use in the Action element to specify the operation on a resource.
Access level: the access level of each operation. The levels are read, write, and list.
Resource type: the type of the resource on which you can authorize the RAM user or the RAM role to perform the operation. Take note of the following items:
- The required resource types are displayed in bold characters.
- If the permissions cannot be granted at the resource level, All Resources is used in the Resource type column of the operation.
Condition Key: the condition key that is defined by the cloud service.
Associated operation: other operations that the RAM user or the RAM role must have permissions to perform to complete the operation. To complete the operation, the RAM user or the RAM role must have the permissions to perform the associated operations.

Operation	Access level	Resource type	Condition key	Associated operation
sts:AssumeRole	get	Role acs:ram::{#accountId}:role/{#RoleName}	none	none

Request parameters

Parameter	Type	Required	Description	Example
DurationSeconds	long	No	The validity period of the STS token. Unit: seconds. Minimum value: 900. Maximum value: the value of the `MaxSessionDuration` parameter. Default value: 3600. You can call the CreateRole or UpdateRole operation to configure the `MaxSessionDuration` parameter. For more information, see CreateRole or UpdateRole .	3600
Policy	string	No	The policy that specifies the permissions of the returned STS token. You can use this parameter to grant the STS token fewer permissions than the permissions granted to the RAM role. If you specify this parameter, the permissions of the returned STS token are the permissions that are included in the value of this parameter and owned by the RAM role. If you do not specify this parameter, the returned STS token has all the permissions of the RAM role. The value must be 1 to 2,048 characters in length. For more information about policy elements and sample policies, see Policy elements and Overview of sample policies.	{"Statement": [{"Action": [""],"Effect": "Allow","Resource": [""]}],"Version":"1"}
RoleArn	string	Yes	The Alibaba Cloud Resource Name (ARN) of the RAM role. The trusted entity of the RAM role is an Alibaba Cloud account. For more information, see Create a RAM role for a trusted Alibaba Cloud account or CreateRole . Format: `acs:ram::<account_id>:role/<role_name>`. You can view the ARN in the RAM console or by calling operations. The following items describe the validity periods of storage addresses: For more information about how to view the ARN in the RAM console, see How do I find the ARN of the RAM role? For more information about how to view the ARN by calling operations, see ListRoles or GetRole .	acs:ram::123456789012****:role/adminrole
RoleSessionName	string	Yes	The custom name of the role session. Set this parameter based on your business requirements. In most cases, you can set this parameter to the identity of the API caller. For example, you can specify a username. You can specify `RoleSessionName` to identify API callers that assume the same RAM role in ActionTrail logs. This allows you to track the users that perform the operations. The value must be 2 to 64 characters in length and can contain letters, digits, and the following special characters: `. @ - _`.	alice
ExternalId	string	No	The external ID of the RAM role. This parameter is provided by an external party and is used to prevent the confused deputy problem. For more information, see Use ExternalId to prevent the confused deputy problem. The value must be 2 to 1,224 characters in length and can contain letters, digits, and the following special characters: `= , . @ : / - _`. The regular expression for this parameter is `[\w+=,.@:\/-]*`.	abcd1234

For more information about common request parameters, see Common parameters.

Response parameters

Parameter	Type	Description	Example
	object	The response parameters.
RequestId	string	The ID of the request.	6894B13B-6D71-4EF5-88FA-F32781734A7F
AssumedRoleUser	object	The temporary identity that you use to assume the RAM role.
AssumedRoleId	string	The ID of the temporary identity that you use to assume the RAM role.	34458433936495****:alice
Arn	string	The ARN of the temporary identity that you use to assume the RAM role.	acs:ram::123456789012****:role/adminrole/alice
Credentials	object	The STS credentials.
SecurityToken	string	The STS token. Note Alibaba Cloud STS does not impose limits on the length of STS tokens. We strongly recommend that you do not specify a maximum length for STS tokens.	********
Expiration	string	The time when the STS token expires. The time is displayed in UTC.	2015-04-09T11:52:19Z
AccessKeySecret	string	The AccessKey secret.	wyLTSmsyPGP1ohvvw8xYgB29dlGI8KMiH2pK****
AccessKeyId	string	The AccessKey ID.	STS.L4aBSCSJVMuKg5U1****

Examples

Sample success responses

JSONformat

{
  "RequestId": "6894B13B-6D71-4EF5-88FA-F32781734A7F",
  "AssumedRoleUser": {
    "AssumedRoleId": "34458433936495****:alice",
    "Arn": "acs:ram::123456789012****:role/adminrole/alice"
  },
  "Credentials": {
    "SecurityToken": "********",
    "Expiration": "2015-04-09T11:52:19Z",
    "AccessKeySecret": "wyLTSmsyPGP1ohvvw8xYgB29dlGI8KMiH2pK****",
    "AccessKeyId": "STS.L4aBSCSJVMuKg5U1****"
  }
}

Error codes

HTTP status code	Error code	Error message
400	InvalidParameter.DurationSeconds	The Min/Max value of DurationSeconds is 15min/1hr.
400	InvalidParameter.ExternalId	The parameter ExternalId is wrongly formed.
400	InvalidParameter.RoleArn	The parameter RoleArn is wrongly formed.
400	InvalidParameter.RoleSessionName	The parameter RoleSessionName is wrongly formed.
400	InvalidParameter.SerialNumber	The parameter SerialNumber is wrongly formed.
400	InvalidParameter.TokenCode	The parameter TokenCode is wrongly formed.
400	InvalidParameter.PolicyGrammar	The parameter Policy has not passed grammar check.
400	InvalidParameter.PolicySize	The size of Policy must be smaller than 2048 bytes.
400	InvalidParameter.ContentType	The ContentType request header must be either "application/json" or "application/x-www-form-urlencoded".
403	NoPermission	You are not authorized to do this action. You should be authorized by RAM.
403	AuthenticationFail.ApiUsername	The specified api username is not legal.
403	AuthenticationFail.ApiPassword	The specified api password is not legal.
403	NoPermission	No permission perform sts:AssumeRole on this Role. Maybe you are not authorized to perform sts:AssumeRole or the specified role does not trust you
403	NoPermission	Roles may not be assumed by root accounts.
404	EntityNotExist.Role	The specified Role not exists .
500	InternalError	STS Server Internal Error happened, please send the RequestId to us.
500	InternalError	STS Server Internal Error happened, please send the RequestId to us.

For a list of error codes, visit the Service error codes.

Change history

Change time	Summary of changes	Operation
2022-09-27	The Error code has changed	View Change Details