[SunRay-Users] xlock screen locking -

ottomeister ottomeister at gmail.com
Fri Jan 26 17:34:58 EET 2007


On 1/25/07, Peter Anderson <pka at they.com.au> wrote:
>         One interesting thing I have noticed is the ownership of the users
>         xscreensaver process changes to root after a card is removed and
>         the screen saver is activated.  When the card is re-inserted,
>         and the user is successfully authenticated, the ownership
>         changes back to the user.  Not sure what's going on there?

xscreensaver switches to running as root when it locks the screen
so that when it invokes PAM to reauthenticate the user the PAM
modules have sufficient privilege to do their jobs correctly.  For
instance, a module might need to read /etc/shadow or other files
that would not be accessible when running under a normal user's
ID.

Once reauthentication is complete xscreensaver goes back to
running with the user's ID in order to reduce the chance of the
xscreensaver process being tricked into doing something that the
user shouldn't be able to do.

>         Is it possible
>         this behaviour is contributing to unresponsive xscreensaver or
>         is this 'normal' (i.e. maybe something to do with session
>         disconnect and ownership of parent processes perhaps)?

This is normal, and required, behaviour.

OttoM.
__
ottomeister

Disclaimer: These are my opinions. I do not speak for my employer.


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