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

[Markus Armbruster]

Peter Lieven <address@hidden> writes:

> On 13.06.2013 12:55, Markus Armbruster wrote:
>> Peter Lieven <address@hidden> writes:
>>
>>> On 13.06.2013 10:40, Stefan Hajnoczi wrote:
>>>> On Thu, Jun 13, 2013 at 08:09:09AM +0200, Peter Lieven wrote:
>>>>> I was thinking if it would be a good idea to zeroize all memory
>>>>> resources on system reset and
>>>>> madvise dontneed them afterwards. 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.
>>>> I wonder if you'll hit weird OS installers or PXE clients that rely on
>>>> stashing stuff in memory across reset.
>>> One point:
>>> Wouldn't a memory test which some systems do at startup break these as well?
>> Systems that distinguish between warm and cold boot (such as PCs)
>> generally run POST only on cold boot.
>>
>> I'm not saying triggering warm reboot and expecting memory contents to
>> survive is a good idea, but it has been done.
> so you would vote for not touching it or at least enable it only through
> a cmdline paramter?

If you can demonstrate practical advantages of clearing memory, we can
talk about how to best do it, and whether it really needs to be
optional.