Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Thu, 6 Sep 2018 16:51:00 +0800
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc:     Gilad Ben-Yossef <gilad@benyossef.com>,
        Kees Cook <keescook@chromium.org>,
        Eric Biggers <ebiggers@google.com>,
        Antoine Tenart <antoine.tenart@bootlin.com>,
        Boris Brezillon <boris.brezillon@bootlin.com>,
        Arnaud Ebalard <arno@natisbad.org>,
        Corentin Labbe <clabbe.montjoie@gmail.com>,
        Maxime Ripard <maxime.ripard@bootlin.com>,
        Chen-Yu Tsai <wens@csie.org>,
        Christian Lamparter <chunkeey@gmail.com>,
        Philippe Ombredanne <pombredanne@nexb.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" 
        <linux-crypto@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 2/2] crypto: skcipher: Remove VLA usage for
 SKCIPHER_REQUEST_ON_STACK
Message-ID: <20180906085100.xcqqftgqg4sizkec@gondor.apana.org.au>
References: <20180904181629.20712-1-keescook@chromium.org>
 <20180904181629.20712-3-keescook@chromium.org>
 <CAKv+Gu9uJ+ZjBSCM=aU0GDvYR72cy2k8reXdLV5on3dOVw8KdQ@mail.gmail.com>
 <CAGXu5jKmcuhULMR=O9B_hJAxEK8uV36uoMxm4F3F8yYSuMzYNA@mail.gmail.com>
 <CAKv+Gu_0vWUqkUex45iW=pAfUbKVsqzP9MDf6OOwTg-nUVPZNg@mail.gmail.com>
 <CAOtvUMfu4-DWD4n4c5itjArAYWhGaBnPBEnkh6cbCubG-k9cCA@mail.gmail.com>
 <CAKv+Gu8bKcPksgoryaVjoD9G5KeCYrqWOCgVhqrBqGw5dCzXag@mail.gmail.com>
 <CAKv+Gu-QkCE0pY4+5anEZ0eWv-FTH1QJtOQfPcTVLcvNf7XNiA@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAKv+Gu-QkCE0pY4+5anEZ0eWv-FTH1QJtOQfPcTVLcvNf7XNiA@mail.gmail.com>
User-Agent: NeoMutt/20170113 (1.7.2)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, Sep 06, 2018 at 10:11:59AM +0200, Ard Biesheuvel wrote:
>
> That way, we will almost certainly oops on a NULL pointer dereference
> right after, but we at least the stack corruption.

A crash is just as bad as a BUG_ON.

Is this even a real problem? Do we have any users of this construct
that is using it on async algorithms?

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