wayland screen locker and security in general

[Jerome Glisse]

2011/4/6 Michal Suchanek <hramrach at centrum.cz>:
> 2011/4/5 Kristian Høgsberg <krh at bitplanet.net>:
>> On Tue, Apr 5, 2011 at 5:59 AM, Michal Suchanek <hramrach at centrum.cz> wrote:
>>> Hello,
>>>
>>> what is the plan for screensave/screenlocker support in wayland?
>>>
>>> The support in X is a fail in several ways.
>>
>> It sure is.  The plan for Wayland is that the lock screen is just part
>> of the compositor.  There are no problems with detecting idle or other
>> applications having grabs this way, and the compositor completely
>> controls what goes on the screen so you don't have other applications
>> raising their window over the screensaver.  There doesn't even have to
>> be a screensaver window, the compositor can just paint a black screen.
>>
>> It is of course possible to define a plugin or an out-of-process (fork
>> a special Wayland client and give it a special surface to render to,
>> similar to your second option below) mechanism for rendering fun
>> screensavers.
>>
>
> IMHO having anything that requires somewhat uncommon functionality as
> part of the compositor is lame. The same if a new plugin is required
> for any new function somebody comes up with.
>
> Eventually there should be multiple compositors to choose from and
> they should *not* each include everything and the kitchen sink.
>
> Thanks
>
> Michal

I don't think it's lame, a good compositor with good theming
capabilities and you will only need one. Moreover you can add very
usefull feature in the compositor regarding locked screen, for
instance you can force the compositor to always composite a small
picture (some kind of icon) on top of fullscreen app so no app can
malisiously present itself as being a screensaver and spy on user
password. Only the compositor would paint without the icon. This is
just one example.

I think wayland design is to avoid redoing X and trying to add new
protocol for screensaver or whatever new application one might come up
with, is to be avoided. Of course that means that piece like the
compositor will have to include bunch of code that were previously
"standalone".

Cheers,
Jerome