Re: crypto: user - Allow get request with empty driver name

From: Stephan Mueller
Date: Thu Nov 20 2014 - 08:07:43 EST

Am Donnerstag, 20. November 2014, 09:04:06 schrieb Steffen Klassert:

Hi Steffen,

> On Thu, Nov 20, 2014 at 03:45:26PM +0800, Herbert Xu wrote:
> > On Thu, Nov 20, 2014 at 08:11:42AM +0100, Steffen Klassert wrote:
> > > I think this is not sufficient, crypto_alg_match() will now return the
> > > first algorithm in crypto_alg_list that matches cra_name. We would need
> > > to extend crypto_alg_match() to return the algorithm with the highest
> > > priority in that case.
> >
> > It doesn't really matter because all implementations must provide
> > exactly the same set of parameters for a given algorithm so it's
> > good enough for what Stephan wants to do.
> Ok, I see.
> > But yes an interface to grab the highest priority algorithm would
> > be useful too so patches are welcome :)
> Should be not too hard to return the highest priority algorithm
> instead of the first match with the existing interface, I'll see
> what I can do.

I think that for the purpose of using crypto-user in an AF_ALG scenario, even
searching for the highest priporty will not necessarily give you the reference
to the cipher used in AF_ALG. In the time between AF_ALG initialized a cipher
and the time crypto-user is called, a new driver could register that may have
even a higher priority than the one driver currently active for AF_ALG.

Therefore, from my perspective of AF_ALG and considering that all drivers of
the same name should be identical, I would not suggest add more code to
resolve the highest priority as I do not see the value of it.

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