Re: [RFC 0/4] make call_usermodehelper a bit more "safe"

From: Jiri Kosina
Date: Mon Dec 19 2016 - 08:34:27 EST


On Fri, 16 Dec 2016, Greg KH wrote:

> > You seem to be targeting a situation where the kernel memory can be
> > easily changed, but filesystem content cannot (if it could - the
> > attacker would simply replace /sbin/hotplug).
>
> Correct, like an embedded system with a read-only system partition, or
> for when some kernel bug allows for random memory writes, yet privilege
> escalation is hard to achieve for your process.

Sorry, I really don't get this.

If kernel memory can be easily changed (which is assumed here), why bother
with all this? I'll just set current->uid to 0 and be done.

--
Jiri Kosina
SUSE Labs