This topic describes the syntax of a SAML response for role-based single sign-on (SSO). This topic also describes the elements of a SAML assertion in a SAML response.
Background information
During SAML 2.0-based SSO, after the identity of a user is verified, the identity provider (IdP) generates an authentication response and sends this response to Alibaba Cloud by using a browser or a program. This response contains a SAML assertion that complies with the specifications of the HTTP POST binding in SAML 2.0. Alibaba Cloud uses the SAML assertion to determine the logon status and identity of the user. Therefore, the SAML assertion must contain the elements that are required by Alibaba Cloud. If the SAML assertion does not contain the required elements, SSO fails.
SAML response
Make sure that each SAML response that is sent by your IdP to Alibaba Cloud contains the following elements. Otherwise, SSO fails.
<saml2p:Response>
<saml2:Issuer>...</saml2:Issuer>
<saml2p:Status>
...
</saml2p:Status>
<saml2:Assertion>
<saml2:Issuer>...</saml2:Issuer>
<ds:Signature>
...
</ds:Signature>
<saml2:Subject>
<saml2:NameID>${NameID}</saml2:NameID>
<saml2:SubjectConfirmation>
...
</saml2:SubjectConfirmation>
</saml2:Subject>
<saml2:Conditions>
<saml2:AudienceRestriction>
<saml2:Audience>${Audience}</saml2:Audience>
</saml2:AudienceRestriction>
</saml2:Conditions>
<saml2:AuthnStatement>
...
</saml2:AuthnStatement>
<saml2:AttributeStatement>
<saml2:Attribute Name="https://www.aliyun.com/SAML-Role/Attributes/RoleSessionName">
...
</saml2:Attribute>
<saml2:Attribute Name="https://www.aliyun.com/SAML-Role/Attributes/Role">
...
</saml2:Attribute>
</saml2:AttributeStatement>
</saml2:Assertion>
</saml2p:Response>
Elements in a SAML assertion
- Common elements in SAML 2.0
Element Description Issuer
The value of the Issuer
element must match the value ofEntityID
in the metadata file that you uploaded for the IdP in the Alibaba Cloud Management Console.Signature
The SAML assertion must be signed. The Signature
element must contain information such as the signature value and signature algorithm. The signature is used to confirm that the signed SAML assertion is not modified after the signature is generated.Subject
The
Subject
element must contain the following sub-elements:- Only one
NameID
sub-element. You must specify the value ofNameID
based on SAML 2.0. However, Alibaba Cloud does not determine a logon identity based on the value of NameID. - Only one
SubjectConfirmation
sub-element that contains aSubjectConfirmationData
sub-element. TheSubjectConfirmationData
sub-element must contain the following attributes:NotOnOrAfter
: the validity period of a SAML assertion.Recipient
: the recipient of the SAML assertion. Alibaba Cloud checks the recipient of the SAML assertion based on the value of this attribute. Therefore, you must set this attribute tohttps://signin.alibabacloud.com/saml-role/sso
.
The following script provides an example of the
Subject
element:<Subject> <NameID Format="urn:oasis:names:tc:SAML:2.0:nameid-format:persistent">administrator</NameID> <SubjectConfirmation Method="urn:oasis:names:tc:SAML:2.0:cm:bearer"> <SubjectConfirmationData NotOnOrAfter="2019-01-01T00:01:00.000Z" Recipient="https://signin.alibabacloud.com/saml-role/sso"/> </SubjectConfirmation> </Subject>
Conditions
The
Conditions
element must contain anAudienceRestriction
sub-element. The AudienceRestriction sub-element can contain one or moreAudience
sub-elements. The value of anAudience
sub-element must beurn:alibaba:cloudcomputing:international
.The following script provides an example of the
Conditions
element:<Conditions> <AudienceRestriction> <Audience>urn:alibaba:cloudcomputing:international</Audience> </AudienceRestriction> </Conditions>
- Only one
- Custom elements required by Alibaba Cloud
Alibaba Cloud requires that the
AttributeStatement
element in a SAML assertion contains the followingAttribute
sub-elements:- Role attribute: an
Attribute
element with theName
attribute set tohttps://www.aliyun.com/SAML-Role/Attributes/Role
This sub-element is required and contains one or more
AttributeValue
sub-elements. AttributeValue lists the roles that can be assumed by a user in your IdP. The value of the AttributeValue sub-element is a comma-delimited pair of the Alibaba Cloud Resource Name (ARN) of the role and the ARN of the IdP. You can view the ARN of the role and the ARN of the IdP in the RAM console.- To view the ARN of the role, go to the Roles page and click the name of the RAM role. On the page that appears, you can view the ARN of the role in the Basic Information section.
- To view the ARN of the IdP, go to the SSO page. On the Role-based SSO tab, click the name of the IdP. You can view the ARN of the IdP in the IdP Information section.
Note If a role attribute contains multiple AttributeValue sub-elements, the user must select which role to assume when the user logs on to the Alibaba Cloud Management Console.The following script provides an example of the
Role
attribute:<Attribute Name="https://www.aliyun.com/SAML-Role/Attributes/Role"> <AttributeValue>acs:ram::$account_id:role/role1,acs:ram::$account_id:saml-provider/provider1</AttributeValue> <AttributeValue>acs:ram::$account_id:role/role2,acs:ram::$account_id:saml-provider/provider1</AttributeValue> </Attribute>
Note The value of$account_id
is the ID of the Alibaba Cloud account that defines the RAM role and IdP. - Role attribute: an
Attribute
element with theName
attribute set tohttps://www.aliyun.com/SAML-Role/Attributes/RoleSessionName
This sub-element is required and contains only one
AttributeValue
sub-element that specifies the user information to be displayed in the RAM console and ActionTrail logs. If you want multiple users to assume the same role, specify different values of theRoleSessionName
attribute for the users. Each value uniquely identifies a user. For example, you can set the value to an employee ID or email address.The value in the
AttributeValue
sub-element must be 2 to 64 characters in length, and can contain only letters, digits, and the following special characters:- _ . @ =
The following script provides an example of the
RoleSessionName
attribute:<Attribute Name="https://www.aliyun.com/SAML-Role/Attributes/RoleSessionName"> <AttributeValue>user_id</AttributeValue> </Attribute>
- SessionDuration attribute: an
Attribute
sub-element with theName
attribute set tohttps://www.aliyun.com/SAML-Role/Attributes/SessionDuration
This element is optional and contains only one
AttributeValue
sub-element that specifies the maximum duration of each session. The value of this sub-element is an integer, in seconds. The value cannot exceed the maximum session duration that is specified for the Role attribute. The minimum value is 900 seconds.The following script provides an example of the
SessionDuration
attribute:<Attribute Name="https://www.aliyun.com/SAML-Role/Attributes/SessionDuration"> <AttributeValue>1800</AttributeValue> </Attribute>
- Role attribute: an
- Maximum role session duration
If you use the console to assume a role, the maximum session duration for the role is the value of the
SessionDuration
attribute that is specified in a SAML assertion. If theSessionNotOnOrAfter
attribute of theAuthnStatement
element is also specified, the maximum session duration is the smaller value betweenSessionDuration
andSessionNotOnOrAfter
. If neither SessionDuration nor SessionNotOnOrAfter is specified, the maximum session duration is the smaller value between the Maximum Session Duration parameter of the role and the Logon Session Valid For parameter. For more information, see Configure security policies for RAM users and Specify the maximum session duration for a RAM role.If you have specified the
DurationSeconds
parameter when you call the AssumeRoleWithSAML operation and defined theSessionNotOnOrAfter
attribute in theAuthnStatement
element, the maximum session duration is the smaller value betweenDurationSeconds
andSessionNotOnOrAfter
. If neither SessionDuration nor SessionNotOnOrAfter is specified, the maximum session duration is 3,600 seconds by default.