Re: [Qemu-devel] [RFC] sanitize memory on system reset

[Andreas Färber]

Hi,

Am 13.06.2013 08:09, schrieb Peter Lieven:
> I was thinking if it would be a good idea to zeroize all memory
> resources on system reset and
> madvise dontneed them afterwards.

The current way of not zeroing memory has led to discovery of some
firmware bugs that we wouldn't have found if QEMU defaulted to zeroing.

> This would avoid system reset attacks
> in case the attacker
> has only access to the console of a vServer but not on the physical host
> and it would shrink
> RSS size of the vServer siginificantly.

Apart from the guest issue Stefan brought up (so far by definition we do
a hard reset, so guests cannot assume soft reset semantics, but we
should keep our options open), would not zeroing while marking pages as
unused be an option? E.g., -reset-memory=DEADBEEF or some other
command-line-specifiable pattern, absence would mean current behavior.

Regards,
Andreas

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