Re: [PATCH 2/2] crypto: ccree: enable support for hardware keys

[Harald Freudenberger <freude@linux.vnet.ibm.com>]

On 04/03/2018 12:19 PM, Herbert Xu wrote:
> On Sat, Mar 31, 2018 at 08:30:46PM +0300, Gilad Ben-Yossef wrote:
>> However, as it uses the exact same mechanism of the regular xts-aes-ccree
>> but takes the key from another source, I've marked it with a test of
>> alg_test_null() on the premise that if the xts-aes-ccree works, so must this.
> Well it appears to be stubbed out as cc_is_hw_key always returns
> false.
>
>>> Are there other crypto drivers doing this?
>> I thought the exact same thing until I ran into a presentation about the s390
>> secure keys implementation. I basically imitated their use (or abuse?)
>> of the Crypto API
>> assuming it is the way to go.
>>
>> Take a look at arch/s390/crypto/paes_s390.c
> It's always nice to discover code that was never reviewed.
>
> The general approach seems sane though.
>
>> Anyway, if this is not the way to go I'd be more than happy to do whatever
>> work is needed to create the right interface.
>>
>> PS. I'd be out of the office and away from email access to the coming week, so
>> kindly excuse any delay in response.
> I think it's fine.  However, I don't really like the idea of everyone
> coming up with their own "paes", i.e., your patch's use of "haes".
> It should be OK to just use paes for everyone, no?
>
> As to your patch specifically, there is one issue where you're
> directly dereferencing the key as a struct.  This is a no-no because
> the key may have come from user-space.  You must treat it as a
> binary blob.  The s390 code seems to do this correctly.
>
> Cheers,
I would be happy to have a generic kernel interface for some kind
of key token as a binary blob. I am also open to use the kernel key
ring for future extensions. But please understand we needed a way
to support our hardware keys and I think the chosen design isn't
so bad.

regards Harald Freudenberger
using the kernel key ring in future extensions.