Re: Native Encryption for ZFS on FreeBSD CFT

From: Allan Jude <allanjude_at_freebsd.org>
Date: Tue, 21 Aug 2018 23:56:02 -0400
On 2018-08-21 23:16, Alan Somers wrote:
> On Tue, Aug 21, 2018 at 9:13 PM Sean Fagan <sef_at_ixsystems.com> wrote:
> 
>> On Aug 21, 2018, at 8:11 PM, Alan Somers <asomers_at_freebsd.org> wrote:
>>> The last time I looked (which was a long time ago), Oracle's ZFS
>> encryption looked extremely vulnerable to watermarking attacks.  Did
>> anybody ever fix that?
>>
>> This isn’t Oracle’s implementation, but I don’t know how compatible or not
>> it is with it.
>>
>> Sean.
>>
> 
> It wasn't just an implementation problem, it was in the design.  IIRC,
> Oracle's encryption allowed encrypted blocks to be deduplicated.  There's
> pretty much no way to defend against watermarking attacks with such a
> design.  Does the new encryption design have the same flaw?
> 
> -Alan
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> 

There is a presentation from the OpenZFS developers summit that walks
through the design. It is not the same as the Oracle version, although
relatively similar.

Video: https://youtu.be/frnLiXclAMo
Slides:
https://drive.google.com/file/d/0B5hUzsxe4cdmU3ZTRXNxa2JIaDQ/view?usp=sharing

It says dedup only works within the same 'clone family', and uses a
unique IV for every block, except when the data is identical (when it
gets deduped)

It isn't clear to me from the presentation if this issue is mitigated or
not. Slide #26 suggests they have done more than Oracle did.


-- 
Allan Jude


Received on Wed Aug 22 2018 - 01:56:13 UTC

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