Enhance UI support for pam_u2f #152
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Adds support for a interactive screen when receiving info/msg from PAM. This means that clock will keep ticking if you receive an error or info message from PAM. This is particularly useful for when using pam_u2f, where you get your U2F token blinking waiting for an input while PAM will be waiting and the screen will be left with a message "Please touch the device". Previously that screen would seem frozen, as the clock (if displayed) would be stopped and your screen would never go blank (if configured). You had two options, either finish the authentication by touching the device, or remove it so it would fail and go back to the fallback authentication mechanism (usually user/password). For that feature to work well, there's also a new env variable you should set (`XSECURELOCK_AUTHPROTO_KILL_ON_TIMEOUT`): it will kill the authproto process responsible for that auth instance. That must be done if the PAM auth module you're using keeps waiting indefinitely for an action from the user, which will inevitably make the screen hang forever if that condition is not met.
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tl;dr
When using
pam_u2for any PAM module that sends a message and awaits for external input:AUTH_TIMEOUTis respected and your screen blanks out correctly (opt-in)Long description
Adds support for an interactive screen when receiving info/msg from PAM.
This means that clock will keep ticking if you receive an error or info message from PAM. This is particularly useful for when using "ui blocking" modules such as
pam_u2f, where you get your U2F device blinking while waiting for an input and PAM will be waiting after leaving you with the message "Please touch the device". Without this patch, that screen would seem frozen, as the clock (if displayed) would be static and your screen would never go blank even after timeout. You had two options, either finish the authentication by touching the device, or remove it so it would fail and go back to the fallback authentication mechanism (usually user/password).For that feature to work well, there's also a new env variable you should set (
XSECURELOCK_AUTHPROTO_KILL_ON_TIMEOUT): it works by killing theauthprotoprocess responsible for that auth instance if timeout is reached or user actively pressesEsc. That step must be done if the PAM auth module you're using keeps waiting indefinitely for an action from the user, which will inevitably make the screen hang forever if that condition is not met.All in all, these features will make the UI more consistent, by making sure that in any type of message received from
authproto, we can behave using the same set of rules, like timeouts and screen updates (so the clock ticks!)