Re: [RFC PATCH] crypto: prevent helper ciphers from being allocated by users

[Stephan Mueller <smueller@chronox.de>]

Am Dienstag, 17. März 2015, 22:45:52 schrieb Herbert Xu:

Hi Herbert,

>On Tue, Mar 17, 2015 at 12:40:12PM +0100, Stephan Mueller wrote:
>> >How about adding a flag to all these internal algorithms and then
>> >change crypto_alg_mod_lookup to disable that flag by default?
>> 
>> The issue with flags is the following: first we have to think about
>> whether we want a black list or white list approach. Your suggestion
>> implies a black list. Black lists for ensuring security is not good
>> IMHO as it has a tendency to miss cases. This especially applies to
>> this area where we have already an indicator for internal ciphers:
>> the prio is so low that it will never ever be selected based on the
>> name. Now, adding a flag means that we mark such an internal cipher
>> twice.
>
>Huh? Using prio is already a black list.
>
>In any case abusing the priority field like this is not acceptable,
>especially when the priority can be set from user-space.

I agree, I forgot about the priority being changable.

I will prepare a proposal with a flag.
>
>Cheers,


Ciao
Stephan