[OLPC Security] Some anti-theft questions

[Benjamin M. Schwartz]

On Tue, 2008-01-22 at 14:45 -0500, Chris Ball wrote:
> Hi,
> 
>    > One easy way to change the RTC date is to remove the watch-battery
>    > that powers it.  I am curious what the intended behavior is in the
>    > case of watch-battery failure, since this is known to be a common
>    > hardware failure mode (the lifetime failure rate is 100%!).
> 
> When OFW finds an unset/invalid date, it automatically expires all
> leases (both activation and developer), which leaves the laptop unable
> to boot.  It will still boot into signed activation images, though, and
> those images can perform NTP sync as well as writing an activation lease
> in order to get the laptop booting again.

Interesting.  The result is that, in the absence of a school server, a
failed watch battery renders the XO completely useless.  Thus, some
students will wonder why their XO only works at school.

For students without school servers and reliable internet connections,
this is especially bad, but those students should not have passive-kill
activated anyway.

If OFW detects a date indicative of a failed battery, it would be very
nice to make that information available to the OS, so that Sugar can pop
up a warning on startup: "Your clock battery has failed.  To use this
laptop outside of school, you must replace this battery."

--Ben