Re: [PATCH] lib: memcmp_nta: add timing-attack secure memcmp

[Daniel Borkmann <dborkman@redhat.com>]

On 02/11/2013 12:50 AM, Greg KH wrote:
> On Mon, Feb 11, 2013 at 12:30:51AM +0100, Daniel Borkmann wrote:
>> On 02/11/2013 12:24 AM, Joe Perches wrote:
>>> On Sun, 2013-02-10 at 23:00 +0100, Daniel Borkmann wrote:
>>>> add memcmp_nta ({n}o {t}iming {a}ttacks)
>>>
>>> Why should this be in the kernel?
>>
>> As the commit message already says, so that current or future (e.g.) network
>> protocol code or modules can make use of this when dealing with cryptographic
>> hash comparisons.
>
> Do we have any in-kernel users that need this?  If not, then don't add
> it now, but rather, add it when we actually have a user.  We almost
> never add kernel functions that no one calls, that would be just
> wasteful.

Agreed, I think there are users for it. But I'll resend a set at a later point
in time, after some more testing and verifying.

Thanks, Greg.