How to change page permission from inside the kernel?

[Rik van Riel]

On Fri, 2018-07-06 at 21:29 +0200, Ahmed Soliman wrote:

> > 2) And why from inside the kernel?
> 
> Because this needs to be done from inside KVM.
> 
> Note: I am aware that this won't be effective against rootkits that
> live in userspace, rootkits that target kernel dynamic data, files on
> disk, as well as VMM escapes, but I believe if the attack surface is
> reduced by just a little bit, it is not that bad, so please lets not
> discuss that :P.

It sounds like the only permission you care about is
the permission of the _guest_ writing to that memory,
not the permission of the qemu-kvm userspace program
writing to that memory.

You may be looking at the wrong page mapping to
manipulate.

-- 
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