Authorization code grant and web single sign-on

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Last updated: 2018-11-06 by Former user (Deleted)Version comment
4 min read


In a web single sign-on use case a single OAuth Client is registered with SSO. This client is a web application running on a web server. 

The client wants to get an access token for calling the userinfo service of SSO. The userinfo service returns claims and attributes describing the authenticated user.

Contents

Sequence diagram of authorization code grant with native applications



Authorization Request

https://tools.ietf.org/html/rfc6749#section-4.1.1
http://openid.net/specs/openid-connect-core-1_0.html#AuthRequest

GET /uas/oauth2/authorization

Required Parameters

  • response_type = code

For authorization code grant the value must be set to "code"

  • scope = openid

For web single sign-on use case the value is set to "openid"

  • client_id 

OAuth Client Identifier of the web application. This value is generated by SSO management when the OAuth Client is registered and activated. See Registeration response

  • redirect_uri

The redirect uri value must have been be registered with SSO management. The authorization server redirects the web browse to this address after authenticating the end-user. See Registeration request

Optional Parameters

  • state

An opaque value used by the client to maintain state between the request and callback

  • nonce

An opaque value used to associate a client session with an ID Token, and to mitigate replay attacks

  • login_hint

The value from login_hint is put into the username field on the login form

  • acr_values

Choose authentication methods that may satisfy the request.

  • ui_locales

Choose the locale used in the login form.

  • max_age

Specifies the allowable elapsed time in seconds since the last time the user was authenticated. If the elapsed time is greater than this value, the user is re-authenticated.

  • prompt

Possible values: none, login, consent, select_acccount. Value none means that the user is not shown a login page at all, which means that user won't be attempted to authenticate unless they already have an existing authentication. Values login, consent and select_account all mean that user is always shown a login page, despite having an existing authentication or not.

  • display

Choose the UI template used in the login form. The template must contain the value of display parameter in the template setting oidc.display. For this setting, please refer to Ubisecure SSO Login UI Customization.

Listing 1. Sample authorization request
GET 
https://sso.example.com/uas/oauth2/authorization?response_type=code&scope=openid&client_id=2001221477
&redirect_uri=https://client.example.com/response&state=40e1bfc0-4587-4859-be08-a58e3fffa37a

 


Authorization Response

https://tools.ietf.org/html/rfc6749#section-4.1.2
http://openid.net/specs/openid-connect-core-1_0.html#AuthResponse


Parameters

  • code

Authorization Code value generated by SSO

Optional Parameters

  • state

Value from authorization request

Listing 2. Sample authorization response
HTTP/1.1 302 Found
Location: https://client.example.com/response?state=40e1bfc0-4587-4859-be08-a58e3fffa37a&code=vn8DO49e%2bZasXSaS7zTNlaiq5Zr9kNdgDbPubfaz7w%2bwgbxHXx8pmuL1F9gvX0id


Access Token Request

https://tools.ietf.org/html/rfc6749#section-4.1.3
http://openid.net/specs/openid-connect-core-1_0.html#TokenRequest

Replaying the same authorization code revokes the previously issued access token for the replayed authorization code.

POST /uas/oauth2/token

Required Parameters

  • grant_type = authorization_code

For token request with authorization code the value must be set to "authorization_code"

Allowed by Default.

  • redirect_uri

The value must be the same that was used for authorization request. See Authorization request.

  • code

Authorization Code value received in Authorization Response. See Authorization Response.

  • client_id & client_secret

OAuth Client Identifier and Secret of the web application. See Registeration response


Listing 3. Sample token request
POST https://sso.example.com/uas/oauth2/token Authorization: Basic MTc2MjQxNDM3NDoqKio=Content-Type: application/x-www-form-urlencoded
grant_type=authorization_code&redirect_uri=https://client.example.com/response&code=QnKskjekHNhYlNKsD3pPKnJ4


Access Token Response

https://tools.ietf.org/html/rfc6749#section-4.1.4
https://tools.ietf.org/html/rfc6749#section-5.1
http://openid.net/specs/openid-connect-core-1_0.html#TokenResponse


Parameters

  • scope = openid

The requested scope value. See Authorization request.

  • expires_in

The lifetime in seconds of the access token

  • token_type = Bearer
  • access_token

Access Token issued by the authorization server

Optional Parameters

  • id_token

If requested scope contains value "openid" then id_token is returned

  • refresh_token

Refresh Token issued by the authorization server. The refresh token may be used in a refresh request to refresh the access token

To see how the refresh token need to be set please refer to chapter OAuth 2.0 Client step 5 in Applications - SSO Management


Listing 4. Sample token response (JSON reformatted for readability)
HTTP/1.1 200 OK
Content-Type: application/json 
{
    "scope": "openid",
    "expires_in": 3600,
    "token_type": "Bearer",
    "access_token": "DSJJU6QhquTUsznTDeDq0eVm",
    "id_token": "eyJhbGciOiJSUzI1NiJ9.eyJz..."
}



ID Token

http://openid.net/specs/openid-connect-core-1_0.html#CodeIDToken
http://openid.net/specs/openid-connect-core-1_0.html#IDToken


  • sub

Value that identifies the end-user

  • iss

Issuer of this response. Appears as "issuer" in authorization server metadata. See chapter Metadata Response in OAuth 2.0 and OpenID Connect metadata.

  • aud

OAuth Client Identifier of recipient

  • exp

Expiration timestamp

  • iat

Time at which this response was issued

  • auth_time

Time when end-user was authenticated

  • amr

Authentication methods reference, expressed as JSON array

  • session_index

SSO session index identifier

Optional Parameters

  • acr

Authentication context class reference. If context class is configured in SSO then value appears here

  • nonce

Value from authorization request. See Authorization request.

The ID Token may contain other name-value parameters (claims) as defined by SSO authorization policy.

UserInfo Request

http://openid.net/specs/openid-connect-core-1_0.html#UserInfoRequest

GET /uas/oauth2/userinfo

Required Parameters

Listing 5. Sample userinfo request
GET
https://sso.example.com/uas/oauth2/userinfoAuthorization: Bearer DSJJU6QhquTUsznTDeDq0eVm


UserInfo Response

http://openid.net/specs/openid-connect-core-1_0.html#UserInfoResponse
http://openid.net/specs/openid-connect-core-1_0.html#IDToken


Parameters

  • sub

Value that identifies the end-user

  • iss

Issuer of this response. Appears as "issuer" in authorization server metadata. See chapter Metadata Response in OAuth 2.0 and OpenID Connect metadata.

  • aud

OAuth Client Identifier of recipient

  • exp

Expiration timestamp

  • iat

Time at which this response was issued

  • auth_time

Time when end-user was authenticated

  • amr

Authentication methods reference, expressed as JSON array

  • session_index

SSO session index identifier

Optional Parameters

  • acr

Authentication context class reference. If context class is configured in SSO then value appears here

The userinfo response may contain other name-value parameters (claims) as defined by SSO authorization policy.


Listing 6. Example userinfo response (JSON reformatted for readability)
HTTP/1.1 200 OK
Content-Type: application/json 
{
	"sub": "***",
	"iss": "https://sso.example.com/uas",
	"aud": "2001221477",
	"exp": 1429700671981,
	"iat": 1429697071971,
	"auth_time": 1429697071527,
	"amr": ["https://sso.example.com/uas/saml2/names/ac/password.1"],
	"session_index": "0a9b62ce8de4"
}

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