From: Kees Cook <keescook@chromium.org>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Andy Shevchenko <andy@kernel.org>,
Rasmus Villemoes <rasmus.villemoes@prevas.dk>,
Marco Elver <elver@google.com>,
Eric Biggers <ebiggers@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
linux-hardening@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 3/3] overflow: Introduce wrapping_inc() and wrapping_dec()
Date: Wed, 7 Feb 2024 08:08:14 -0800 [thread overview]
Message-ID: <202402070806.445F7F7F03@keescook> (raw)
In-Reply-To: <CAHp75Vf3emnw-=it-Smb_NG+xYjWhB+U0+i1hcNPWA=BByN6nw@mail.gmail.com>
On Wed, Feb 07, 2024 at 05:31:54PM +0200, Andy Shevchenko wrote:
> On Wed, Feb 7, 2024 at 5:24 PM Kees Cook <keescook@chromium.org> wrote:
> >
> > This allows replacements of the idioms "var += offset" and "var -= offset"
> > with the wrapping_inc() and wrapping_dec() helpers respectively. They
> > will avoid wrap-around sanitizer instrumentation.
> >
> > Add to the selftests to validate behavior and lack of side-effects.
>
> I would expect inc/dec to add/subtract 1. So, to me the terminology is
> confusing. The list of the C/C++ operators on Wikipedia describes
> above as
>
> += Assignment by sum
> -= Assignment by difference
>
>
> Hence the proposal is to have
>
> wrapping_sum()
> wrapping_diff()
I think maybe the missing phrase is "assign", which is what makes
argument 1 "special" -- it's being changed. Perhaps:
wrapping_add_assign()
wrapping_sub_assign()
?
--
Kees Cook
next prev parent reply other threads:[~2024-02-07 16:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-07 15:24 [PATCH v5 0/3] overflow: Introduce wrapping helpers Kees Cook
2024-02-07 15:24 ` [PATCH v5 1/3] overflow: Adjust check_*_overflow() kern-doc to reflect results Kees Cook
2024-02-07 15:24 ` [PATCH v5 2/3] overflow: Introduce wrapping_add(), wrapping_sub(), and wrapping_mul() Kees Cook
2024-02-07 18:06 ` Marco Elver
2024-02-07 15:24 ` [PATCH v5 3/3] overflow: Introduce wrapping_inc() and wrapping_dec() Kees Cook
2024-02-07 15:31 ` Andy Shevchenko
2024-02-07 16:08 ` Kees Cook [this message]
2024-02-07 16:34 ` Andy Shevchenko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=202402070806.445F7F7F03@keescook \
--to=keescook@chromium.org \
--cc=akpm@linux-foundation.org \
--cc=andy.shevchenko@gmail.com \
--cc=andy@kernel.org \
--cc=ebiggers@kernel.org \
--cc=elver@google.com \
--cc=gustavoars@kernel.org \
--cc=linux-hardening@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=rasmus.villemoes@prevas.dk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.