7.4. Authorization policies¶
The scope authorization provides means to define what should happen if a user proved his identity and authenticated successfully.
Authorization policies take the realm, the user and the client into account.
Technically the authorization policies apply to the Validate endpoints and are checked using Policy Module and Policy Decorators.
The following actions are available in the scope authorization:
7.4.1. authorized¶
This is the basic authorization, that either grants the user access or denies access via the /validate
endpoints (see Validate endpoints).
The default behaviour is to grant access, if and after the user has authenticated successfully.
Using authorized=deny_access specific authentication requests can be denied, even if the user has provided
the correct credentials.
In combination with different IP addresses and policy priorities the administrator can generically deny_access with the lowest policy priority and grant_access for specific requests e.g. originating from specific IP addresses to certain users by defining higher policy priorities.
Note
Since authorized is checked as a postpolicy the OTP value used during an authentication attempt will be invalidated even if the authorized policy denies the access.
Note
The actual “success” of the authentication can be changed to “failed” by this postpolicy.
I.e. pre-event handlers
(Pre and Post Handling) would still see the request as successful before it would be changed by
this policy and match the event handler condition result value == True.
7.4.2. tokentype¶
type: string
Users will only be authorized with this very tokentype. The string can hold a space separated list of case sensitive tokentypes. It should look like:
hotp totp spass
This is checked after the authentication request, so that a valid OTP value is wasted, so that it can not be used, even if the user was not authorized at this request
Note
Combining this with the client IP you can use this to allow remote access to sensitive areas only with one special token type while allowing access to less sensitive areas with other token types.
7.4.3. application_tokentype¶
type: bool
Warning
Deprecated since 2.4.0
This policy does not apply any more. Every application can now define its requested tokentype.
If this policy is set, an application may add a parameter type as
tokentype in the authentication request like validate/check, validate/samlcheck
or validate/triggerchallenge.
Then the application can determine via this parameter, which tokens of a user should be checked.
E.g. when using this in triggerchallenge, an application could assure, that only SMS tokens are used for authentication.
7.4.4. serial¶
type: string
Users will only be authorized with the serial number. The string can hold a regular expression as serial number.
This is checked after the authentication request, so that a valid OTP value is wasted, so that it can not be used, even if the user was not authorized at this request
Note
Combining this with the client IP you can use this to allow remote access to sensitive areas only with hardware tokens like the Yubikey, while allowing access to less secure areas also with a Google Authenticator.
7.4.5. tokeninfo¶
type: string
Users will only be authorized if the tokeninfo field of the token matches this regular expression.
This is checked after the authentication request, so that a valid OTP value can not be used anymore, even if authorization is forbidden.
A valid action could look like:
action = key/regexp/
Example:
action = last_auth/^2018.*/
This would mean the tokeninfo field needs to start with “2018”.
7.4.6. setrealm¶
type: string
This policy is checked before the user authenticates. The realm of the user matching this policy will be set to the realm in this action.
Note
This can be used if the user can not pass his realm when authenticating at a certain client, but the realm needs to be available during authentication since the user is not located in the default realm.
7.4.7. no_detail_on_success¶
type: bool
Usually an authentication response returns additional information like the serial number of the token that was used to authenticate or the reason why the authentication request failed.
If this action is set and the user authenticated successfully this additional information will not be returned.
7.4.8. no_detail_on_fail¶
type: bool
Usually an authentication response returns additional information like the serial number of the token that was used to authenticate or the reason why the authentication request failed.
If this action is set and the user fails to authenticate this additional information will not be returned.
7.4.9. api_key_required¶
type: bool
This policy is checked before the user is validated.
You can create an API key, that needs to be passed to use the validate API. If an API key is required, but no key is passed, the authentication request will not be processed. This is used to avoid denial of service attacks by a rogue user sending arbitrary requests, which could result in the token of a user being locked.
You can also define a policy with certain IP addresses without issuing API keys. This would result in “blocking” those IP addresses from using the validate endpoint.
You can issue API keys like this:
edumfa-manage api createtoken -r validate
The API key (Authorization token) which is generated is valid for 365 days.
The authorization token has to be used as described in Authentication endpoints.
7.4.10. auth_max_success¶
type: string
Here you can specify how many successful authentication requests a user is allowed to perform during a given time. If this value is exceeded, the authentication attempt is canceled.
Specify the value like 2/5m meaning 2 successful authentication requests
per 5 minutes. If during the last 5 minutes 2 successful authentications were
performed the authentication request is discarded. The used OTP value is
invalidated.
Allowed time specifiers are s (second), m (minute) and h (hour).
Note
This policy depends on reading the audit log. If you use a non readable audit log like Logger Audit this policy will not work.
7.4.11. auth_max_fail¶
type: string
Here you can specify how many failed authentication requests a user is allowed to perform during a given time.
If this value is exceeded, authentication is not possible anymore. The user will have to wait.
If this policy is not defined, the normal behaviour of the failcounter applies. (see failcount)
Specify the value like 2/1m meaning 2 successful authentication requests
per minute. If during the last 5 minutes 2 successful authentications were
performed the authentication request is discarded. The used OTP value is
invalidated.
Allowed time specifiers are s (second), m (minute) and h (hour).
Note
This policy depends on reading the audit log. If you use a non readable audit log like Logger Audit this policy will not work.
7.4.12. last_auth¶
type: string
You can define if an authentication should fail, if the token was not successfully used for a certain time.
Specify a value like 12h, 123d or 2y to disallow authentication,
if the token was not successfully used for 12 hours, 123 days or 2 years.
The date of the last successful authentication is store in the tokeninfo field of a token and denoted in UTC.
7.4.13. u2f_req¶
type: string
Only the specified U2F devices are authorized to authenticate. The administrator can specify the action like this:
u2f_req=subject/.*Yubico.*/
The the key word can be “subject”, “issuer” or “serial”. Followed by a regular expression. During registration of the U2F device the information from the attestation certificate is stored in the tokeninfo. Only if the regexp matches this value, the authentication with such U2F device is authorized.
7.4.14. add_user_in_response¶
type: bool
In case of a successful authentication additional user information is added
to the response. A dictionary containing user information is added in
detail->user.
7.4.15. add_resolver_in_response¶
type: bool
In case of a successful authentication the resolver and realm of the user are added
to the response. The names are added in
detail->user-resolver and detail->user-realm.
7.4.16. webauthn_authenticator_selection_list¶
type: string
This action configures a whitelist of authenticator models which may be authorized. It is a space-separated list of AAGUIDs. An AAGUID is a hexadecimal string (usually grouped using dashes, although these are optional) identifying one particular model of authenticator. To limit enrollment to a few known-good authenticator models, simply specify the AAGUIDs for each model of authenticator that is acceptable. If multiple policies with this action apply, the set of acceptable authenticators will be the union off all authenticators allowed by the various policies.
If this action is not configured, all authenticators will be deemed acceptable, unless limited through some other action.
Note
If you configure this, you will likely also want to configure webauthn_authenticator_selection_list
7.4.17. webauthn_req¶
type: string
This action allows filtering of WebAuthn tokens by the fields of the attestation certificate.
The action can be specified like this:
webauthn_req=subject/.*Yubico.*/
The the key word can be “subject”, “issuer” or “serial”. Followed by a regular expression. During registration of the WebAuthn authenticator the information is fetched from the attestation certificate. Only if the attribute in the attestation certificate matches accordingly the token can be enrolled.
Note
If you configure this, you will likely also want to configure webauthn_req