linux-kernel - Re: [dm-devel] [PATCH v2 10/11] crypto: ahash: Remove VLA usage for AHASH_REQUEST_ON

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAGXu5jL=p28A=NtVpjjPVLeq4VvBweNjP-K_MWqde-kwDEn2TA@mail.gmail.com>
Date:   Wed, 27 Jun 2018 11:12:12 -0700
From:   Kees Cook <keescook@...omium.org>
To:     Herbert Xu <herbert@...dor.apana.org.au>
Cc:     Eric Biggers <ebiggers3@...il.com>,
        Giovanni Cabiddu <giovanni.cabiddu@...el.com>,
        Arnd Bergmann <arnd@...db.de>,
        Eric Biggers <ebiggers@...gle.com>,
        Mike Snitzer <snitzer@...hat.com>,
        "Gustavo A. R. Silva" <gustavo@...eddedor.com>,
        qat-linux@...el.com, LKML <linux-kernel@...r.kernel.org>,
        dm-devel@...hat.com, linux-crypto <linux-crypto@...r.kernel.org>,
        Lars Persson <larper@...s.com>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        "David S. Miller" <davem@...emloft.net>,
        Alasdair Kergon <agk@...hat.com>,
        Rabin Vincent <rabinv@...s.com>
Subject: Re: [dm-devel] [PATCH v2 10/11] crypto: ahash: Remove VLA usage for AHASH_REQUEST_ON_STACK

On Wed, Jun 27, 2018 at 7:34 AM, Herbert Xu <herbert@...dor.apana.org.au> wrote:
> On Tue, Jun 26, 2018 at 10:02:31AM -0700, Kees Cook wrote:
>>
>> There is no SHASH_MAX_REQSIZE?
>>
>> As for users of AHASH_REQUEST_ON_STACK, I see:
>
> These users are only using the top-level ahash interface.  The
> underlying algorithms must all be shas.

typo? "shash" you mean?

I don't really understand the crypto APIs -- are you or Eric able to
help me a bit more here? I don't understand that things can wrap other
things, so I'm not sure the best way to reason about the maximum size
to choose here. (And the same for skcipher.)

-Kees

-- 
Kees Cook
Pixel Security