When a user logs in to Workbench, they receive a newly created token (a long string of random characters) which grants access to the Arvados API on behalf of that user. In the default configuration, this token does not expire until the user explicitly logs out.
Security policies, such as those required to comply with regulations such as HIPAA and GxP, may include policies for “automatic logoff”. In order to limit the window of risk associated with unauthorized access of the desktop of an Arvados user, or a token being leaked, Arvados offers options for automatic logout from the web app, and to configure access tokens to expire by default.
API.MaxTokenLifetime options give the administrator ways to control automatic expiration of tokens granted through the login flow.
Workbench.IdleTimeout to configure Workbench 2 for automatic logout after a period of idle time. For example, this configuration would log the user out after five minutes of no keyboard or pointer activity:
Clusters: zzzzz: ... Workbench: IdleTimeout: 5m ...
When idle timeout is set, several behaviors and considerations apply:
The default value for
Workbench.IdleTimeout is zero, which disables auto-logout.
Login.TokenLifetime to set the lifetime for tokens issued through the login process. This is the maximum amount of time a user can maintain a session before having to log in again. This setting applies to both regular and admin user logins. Here is an example configuration that would require the user to log in again after 12 hours:
Clusters: zzzzz: ... Login: TokenLifetime: 12h ...
This is independent of
Workbench.IdleTimeout. Even if Workbench auto-logout is disabled, this option will ensure that the user is always required to log in again after the configured amount of time.
Clusters: zzzzz: ... Login: TrustLoginTokens: false ...
When `TrustLoginTokens` is `false`, tokens issued through login will be “untrusted” by default. Untrusted tokens cannot be used to list other tokens issued to the user, and cannot be used to grant new tokens. This stops an attacker from leveraging a leaked token to aquire other tokens, but also interferes with some Workbench features that create new tokens on behalf of the user.
The default value
Login.TokenLifetime is zero, meaning login tokens do not expire (unless
API.MaxTokenLifetime is set).
API.MaxTokenLifetime to set the maximum lifetime for any access token created by regular (non-admin) users. For example, this configuration would require that all tokens expire after 24 hours:
Clusters: zzzzz: ... API: MaxTokenLifetime: 24h ...
Tokens created without an explicit expiration time, or that exceed maximum lifetime, will be set to
Login.TokenLifetime, this option ensures that the user is always required to log in again after the configured amount of time.
Login.TokenLifetime, this applies to all API operations that manipulate tokens, regardless of whether the token was created by logging in, or by using the API. If
Login.TokenLifetime is greater than
API.MaxTokenLifetime, MaxTokenLifetime takes precedence.
Admin users are permitted to create tokens with expiration times further in the future than
The default value
MaxTokenLifetime is zero, which means there is no maximum token lifetime.
Workbench.IdleTimeout only affects browser behavior. It is strongly recommended that automatic browser logout be used together with
Login.TokenLifetime, which is enforced on API side.
TrustLoginTokens: true (default value) is less restrictive. Be aware that an unrestricted token can be “refreshed” to gain access for an indefinite period. This means, during the window that the token is valid, the user is permitted to create a new token, which will have a new expiration further in the future (of course, once the token has expired, this is no longer possible). Unrestricted tokens are required for some Workbench features, as well as ease of use in other contexts, such as the Arvados command line. This option is recommended if many users will interact with the system through the command line.
TrustLoginTokens: false is more restrictive. A token obtained by logging into Workbench cannot be “refreshed” to gain access for an indefinite period. However, it interferes with some Workbench features, as well as ease of use in other contexts, such as the Arvados command line. This option is recommended only if most users will only ever interact with the system through Workbench or WebShell. For users or service accounts that need to tokens with fewer restrictions, the admin can create a token at the command line using the
In every case, admin users may always create tokens with expiration dates far in the future.
These policies do not apply to tokens created by the API server for the purposes of authorizing a container to run, as those tokens are automatically expired when the container is finished.
If you have an existing Arvados installation and want to set a token lifetime policy, there may be long-lived user tokens already granted. The administrator can use the following
rake tasks to enforce the new policy.
db:check_long_lived_tokens task will list which users have tokens with no expiration date.
# bundle exec rake db:check_long_lived_tokens Found 6 long-lived tokens from users: user2,email@example.com,zzzzz-tpzed-5vzt5wc62k46p6r admin,firstname.lastname@example.org,zzzzz-tpzed-6drplgwq9nm5cox user1,email@example.com,zzzzz-tpzed-ftz2tfurbpf7xox
To apply the new policy to existing tokens, use the
# bundle exec rake db:fix_long_lived_tokens Setting token expiration to: 2020-08-25 03:30:50 +0000 6 tokens updated.
NOTE: These rake tasks adjust the expiration of all tokens except those belonging to the system root user (
zzzzz-tpzed-000000000000000). If you have tokens used by automated service accounts that need to be long-lived, you can create tokens that don’t expire using the command line .
The content of this documentation is licensed under the
Commons Attribution-Share Alike 3.0 United States licence.
Code samples in this documentation are licensed under the Apache License, Version 2.0.