linux-kernel - Re: crypto: user - crypto_alg

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5712678.BzXY8HRRHr@tauon>
Date:	Tue, 25 Nov 2014 10:00:01 +0100
From:	Stephan Mueller <smueller@...onox.de>
To:	Steffen Klassert <steffen.klassert@...unet.com>
Cc:	Herbert Xu <herbert@...dor.apana.org.au>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: crypto: user - crypto_alg_match removal

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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/