[dm-devel] xts fuzz testing and lack of ciphertext stealing support

[Horia Geanta]

On 8/9/2019 9:45 AM, Ard Biesheuvel wrote:
> On Fri, 9 Aug 2019 at 05:48, Herbert Xu <herbert at gondor.apana.org.au> wrote:
>>
>> On Thu, Aug 08, 2019 at 06:01:49PM +0000, Horia Geanta wrote:
>>>
>>> -- >8 --
>>>
>>> Subject: [PATCH] crypto: testmgr - Add additional AES-XTS vectors for covering
>>>  CTS (part II)
>>
>> Patchwork doesn't like it when you do this and it'll discard
>> your patch.  To make it into patchwork you need to put the new
>> Subject in the email headers.
>>
> 
> IMO, pretending that your XTS implementation is compliant by only
I've never said that.
Some parts are compliant, some are not.

> providing test vectors with the last 8 bytes of IV cleared is not the
> right fix for this issue. If you want to be compliant, you will need
It's not a fix.
It's adding test vectors which are not provided in the P1619 standard,
where "data unit sequence number" is at most 5B.

> to provide a s/w fallback for these cases.
> 
Yes, the plan is to:

-add 16B IV support for caam versions supporting it - caam Era 9+,
currently deployed in lx2160a and ls108a

-remove current 8B IV support and add s/w fallback for affected caam versions
I'd assume this could be done dynamically, i.e. depending on IV provided
in the crypto request to use either the caam engine or s/w fallback.

Horia