Bug#890891: systemd: PID1 getting stuck printing "systemd[1]: Time has been changed" continuously

[Gert Wollny]

Am Dienstag, den 20.02.2018, 13:33 +0100 schrieb Michael Biebl:
> Am
> 
> > make it lock up in this loop, but if someone can spoof this kind of
> > message and the system locks up because of this, wouldn't this be a
> > typical DoS attack?
> 
> How could an unprivileged user spoof such messages?

I am by no means a security expert, but doesn't the story usually go:
someone finds a bug that allows an escalation of rights that allows
them to do certain things, in the extreme case they can open a root
shell, in another case they may be able to set the RTC to a bogus value
that triggers the kernel to flood timerfd with messages that lock up
the system. Of course that is not a very likely scenario, but to me it
seems possible.