Re: crypto: user - crypto_alg_match removal

[Stephan Mueller]

Am Dienstag, 25. November 2014, 09:42:25 schrieb Steffen Klassert:

Hi Steffen,

>On Mon, Nov 24, 2014 at 01:29:10PM +0100, Stephan Mueller wrote:
>> Am Montag, 24. November 2014, 08:22:46 schrieb Steffen Klassert:
>> > With crypto_alg_lookup() we don't know whether the match is based
>> > on
>> > the driver or the algorithm name. That's why we have
>> > crypto_alg_match(), here we can ask for a driver or an algorithm
>> > match. In some situations it is important to have an exact match
>> > on the crypto driver name. For example if a user wants to
>> > instantiate or delete a certain inplementation of an algorithm. In
>> > this case we need to know whether this exact algorithm driver is
>> > registered in the system.
>> 
>> I understand. But going with the logic of the kernel crypto API, if
>> one needs an exact match, you pick the driver name. Otherwise the
>> generic name. crypto_alg_lookup returns the exact algo when you
>> supply a driver name. It returns the algo with the highest prio when
>> you supply a generic name.
>> 
>> I do not see a difference for the scenarios you describe.
>
>Well, I think there is a small but important difference. If a user
>requests a driver name that would match an algorithm name (i.e.
>cbc(aes) instead of cbc(aes-asm)) crypto_alg_lookup() returns the
>algorithm with the highest priority instead of telling that we don't
>have a driver with the name cbc(aes).

Agreed. If this is a use case scenario that is needed, crypto_alg_lookup 
is not suitable.

Thanks for the clarification.

Ciao
Stephan
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