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

[Herbert Xu <herbert@gondor.apana.org.au>]

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.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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