Received-SPF: pass (google.com: domain of linux-kernel+bounces-166604-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
Date: Thu, 2 May 2024 07:54:10 -0700
From: Kees Cook <keescook@chromium.org>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Andy Shevchenko <andy@kernel.org>, linux-hardening@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] string: Add additional __realloc_size() annotations for
 "dup" helpers
Message-ID: <202405020745.725A922@keescook>
References: <20240501233201.work.732-kees@kernel.org>
 <CAHp75VetkKYhnOaoM880D+VTR96NscQfBGddgAwKz681Uk5ZJg@mail.gmail.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <CAHp75VetkKYhnOaoM880D+VTR96NscQfBGddgAwKz681Uk5ZJg@mail.gmail.com>

On Thu, May 02, 2024 at 12:45:33PM +0300, Andy Shevchenko wrote:
> On Thu, May 2, 2024 at 2:32 AM Kees Cook <keescook@chromium.org> wrote:
> >
> > Several other "dup"-style interfaces could use the __realloc_size()
> > attribute. (As a reminder to myself and others: "realloc" is used here
> > instead of "alloc" because the "alloc_size" attribute implies that the
> > memory contents are uninitialized. Since we're copying contents into the
> > resulting allocation, it must use "realloc_size" to avoid confusing the
> > compiler's optimization passes.)
> >
> > Add KUnit test coverage where possible. (KUnit still does not have the
> > ability to manipulate userspace memory.)
> 
> Makes sense to me,
> Reviewed-by: Andy Shevchenko <andy@kernel.org>
> 
> ...
> 
> > +               checker(len, kmemdup_array(test_phrases[idx], len, 1,   \
> > +                                          gfp), kfree(p));             \
> 
> Despite being longer, I would put gfp on the previous line for the
> sake of logical split (and additionally to be consistent with the
> below).
> 
> > +               checker(len, kmemdup(test_phrases[idx], len, gfp),      \
> > +                       kfree(p));                                      \

Oh good! This bothered me to no end too. I will adjust it. :) Thanks!

-Kees

-- 
Kees Cook