linux-kernel - Re: [PATCH v2] minmax: clamp more efficiently by avoiding extra comparison

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: <YzF4NrcBkR/p0cD3@smile.fi.intel.com>
Date:   Mon, 26 Sep 2022 13:00:22 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     "Jason A. Donenfeld" <Jason@...c4.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org, Kees Cook <keescook@...omium.org>,
        linux-toolchains@...r.kernel.org
Subject: Re: [PATCH v2] minmax: clamp more efficiently by avoiding extra
 comparison

On Sat, Sep 24, 2022 at 12:37:26PM +0200, Jason A. Donenfeld wrote:
> On Fri, Sep 23, 2022 at 03:54:12PM -0700, Andrew Morton wrote:
> > On Fri, 23 Sep 2022 17:40:01 +0200 "Jason A. Donenfeld" <Jason@...c4.com> wrote:

...

> Worth noting, by the way, is that the input validation check already
> caught a bug when 0day test bot choked:
> 
> https://lore.kernel.org/linux-hwmon/20220924101151.4168414-1-Jason@zx2c4.com/

Hooray, it was a good idea! :-)

> So, options:
> 1) Keep this patch as-is, because it is useful on modern compilers.
> 2) Add an ifdef on compiler version, so we generate the best code in
>    each case.
> 3) Go back to testing twice, but keep the checker macro because it's
>    apparently useful.
> 4) Do nothing and discard this series.
> 
> Any of those are okay with me. Opinions?

I tend to case 3) (I believe you typo'ed double 2) cases) and apply the rest
as a separate change with all downsides explained (kinda 1) approach).

-- 
With Best Regards,
Andy Shevchenko