From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paul Mackerras <paulus@ozlabs.org>
Date: Fri, 03 Aug 2018 03:13:15 +0000
Subject: Re: [PATCH] ppp: mppe: Remove VLA usage
Message-Id: <20180803031315.GA30807@fergus>
List-Id: <linux-ppp.vger.kernel.org>
References: <20180716040516.GA32783@beast>
 <CAK8P3a1tph9VPJnYYhBvH_1wZ79wXDvfnJt_CEruj3T-TBG1jg@mail.gmail.com>
 <CAGXu5jKaNk8x9v+uVQ_O7gxr50s1-Q901JbQupnkBFYiUjd7UQ@mail.gmail.com>
In-Reply-To: <CAGXu5jKaNk8x9v+uVQ_O7gxr50s1-Q901JbQupnkBFYiUjd7UQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
To: Kees Cook <keescook@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>, "David S. Miller" <davem@davemloft.net>, Herbert Xu <herbert@gondor.apana.org.au>, Eric Biggers <ebiggers@google.com>, "Gustavo A. R. Silva" <gustavo@embeddedor.com>, linux-ppp@vger.kernel.org, Networking <netdev@vger.kernel.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>

On Thu, Aug 02, 2018 at 04:27:01PM -0700, Kees Cook wrote:
> On Mon, Jul 16, 2018 at 4:01 AM, Arnd Bergmann <arnd@arndb.de> wrote:
> > On Mon, Jul 16, 2018 at 6:05 AM, Kees Cook <keescook@chromium.org> wrote:
> >> In the quest to remove all stack VLA usage from the kernel[1], this
> >> removes the discouraged use of AHASH_REQUEST_ON_STACK (and associated
> >> VLA) by switching to shash directly and keeping the associated descriptor
> >> allocated with the regular state on the heap.
> >>
> >> [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
> >>
> >> Signed-off-by: Kees Cook <keescook@chromium.org>
> >
> > I had concerns at first that this approach might make it slower, but
> > upon reading through implementation of the shash_ahash_ implementation,
> > I concluded that it can only be better than before, improving both
> > performance and stack usage.
> >
> > Acked-by: Arnd Bergmann <arnd@arndb.de>
> 
> Paul,
> 
> Is this something you can take via your tree?

No, it would go via the netdev tree, I expect.

Paul.