linux-kernel - Re: [PATCH] In crypto_add_alg(), 'exact' wants to be initialized to 0

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Message-ID: <alpine.LNX.2.00.1202021541440.12088@swampdragon.chaosbits.net>
Date:	Thu, 2 Feb 2012 15:42:43 +0100 (CET)
From:	Jesper Juhl <jj@...osbits.net>
To:	Steffen Klassert <steffen.klassert@...unet.com>
cc:	"devendra.aaru" <devendra.aaru@...il.com>,
	Herbert Xu <herbert@...dor.apana.org.au>,
	"David S. Miller" <davem@...emloft.net>,
	linux-kernel@...r.kernel.org, linux-crypto@...r.kernel.org
Subject: Re: [PATCH] In crypto_add_alg(), 'exact' wants to be initialized to
 0

On Thu, 2 Feb 2012, Steffen Klassert wrote:

> On Wed, Feb 01, 2012 at 09:21:39PM +0100, Jesper Juhl wrote:
> > On Wed, 1 Feb 2012, devendra.aaru wrote:
> > 
> > > On Sun, Jan 29, 2012 at 5:39 PM, Jesper Juhl <jj@...osbits.net> wrote:
> > > > We declare 'exact' without initializing it and then do:
> > > >
> > > > [...]
> > > >        if (strlen(p->cru_driver_name))
> > > >                exact = 1;
> > > >
> > > >        if (priority && !exact)
> > > >                return -EINVAL;
> > > >
> > > > [...]
> > > >
> > > > If the first 'if' is not true, then the second will test an
> > > > uninitialized 'exact'.
> > > 
> > > not needed . as the cru_driver_name will always be present :).
> > 
> > If that is indeed the case, and we are guaranteed that, then it would seem 
> > that a patch like the following would be what we want instead??
> > 
> > Please note that this patch is intended just for discussion, nothing else 
> > (which is why I left out a Signed-off-by on purpose), since I've not 
> > tested it beyond checking that it compiles, nor have I verified your claim 
> > that cru_driver_name will always be present.
> > 
> 
> We get cru_driver_name from a netlink message that a user sends us.
> So it depends pretty much on the user whether cru_driver_name is
> set or not. Usually it is set when a user wants to instantiate
> a certain algorithm driver, like "cbc(aes-asm)". If the user just
> wants to instantiate the system default of an algorithm, he can
> set cru_name (e.g. to "cbc(aes)") instead of cru_driver_name.
> 
> Your first patch is correct.
> 
Thank you for the explanation.

Can I take that to mean that I can add your Acked-by: if/when I resend the 
patch?

-- 
Jesper Juhl <jj@...osbits.net>       http://www.chaosbits.net/
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