Re: [Qemu-devel] [Qemu-stable] [PATCH] fdc: force the fifo access to be in bounds of the allocated buffer

[Peter Lieven <pl@kamp.de>]

Am 13.05.2015 um 22:03 schrieb John Snow:
>
> On 05/13/2015 04:02 PM, Peter Lieven wrote:
>> Am 13.05.2015 um 21:52 schrieb Markus Armbruster:
>>> Peter Lieven <pl@kamp.de> writes:
>>>
>>>> Am 13.05.2015 um 21:09 schrieb Stefan Priebe:
>>>>> Am 13.05.2015 um 21:05 schrieb Stefan Weil:
>>>>>> Am 13.05.2015 um 20:59 schrieb Stefan Priebe:
>>>>>>> Am 13.05.2015 um 20:51 schrieb Stefan Weil:
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>> I just noticed this patch because my provider told me that my KVM based
>>>>>>>> server
>>>>>>>> needs a reboot because of a CVE (see this German news:
>>>>>>>> http://www.heise.de/newsticker/meldung/Venom-Schwachstelle-Aus-Hypervisor-ausbrechen-und-VMs-ausspionieren-2649614.html)
>>>>>>>>
>>>>>>> Isn't a live migration to a fixed version enough instead of a reboot?
>>>>>>>
>>>>>>> Stefan
>>>>>> Good point. A live migration would be sufficient - if there are no bugs
>>>>>> in QEMU's live migration.
>>>>> just migrating all our customer machines and wanted to be sure that
>>>>> live migration is enough.
>>>> Just to confirm: If Qemu is started with -nodefaults and there is no
>>>> fdc configuration the system is not affected by this CVE?
>>> Not true.  The FD controller is still there.  It has no drives attached
>>> then, but is vulnerable all the same.
>> Are you sure? With -nodefaults the hmp command 'info block' returns nothing and
>> the guest sees no floppy drive.
>>
>> Without -nodefaults I indeed see floppy0 and I have /dev/fd0 in the guest respectively.
>>
>> Peter
>>
> It's not the *drive* that is the problem, it is the *controller*.
>
Okay, and indeed in the qtree I see the isa-fdc.

Thanks for sorting that out.

Thank you,
Peter