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References: <20230925-strncpy-drivers-input-misc-axp20x-pek-c-v2-1-ff7abe8498d6@google.com>
 <202309251100.A187272A49@keescook>
In-Reply-To: <202309251100.A187272A49@keescook>
Reply-To: wens@csie.org
From:   Chen-Yu Tsai <wens@csie.org>
Date:   Tue, 26 Sep 2023 11:10:31 +0800
Message-ID: <CAGb2v64W3oa6g-Ln2wVqXU4eVa-tY=zhvooAXckzDve8_fR-gQ@mail.gmail.com>
Subject: Re: [PATCH v2] Input: axp20x-pek - avoid needless newline removal
To:     Kees Cook <keescook@chromium.org>
Cc:     Justin Stitt <justinstitt@google.com>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org
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On Tue, Sep 26, 2023 at 2:00 AM Kees Cook <keescook@chromium.org> wrote:
>
> On Mon, Sep 25, 2023 at 04:31:05AM +0000, Justin Stitt wrote:
> > This code is doing more work than it needs to.
> >
> > Before handing off `val_str` to `kstrtouint()` we are eagerly removing
> > any trailing newline which requires copying `buf`, validating it's
> > length and checking/replacing any potential newlines.
> >
> > kstrtouint() handles this implicitly:
> > kstrtouint ->
> >   kstrotoull -> (documentation)
> > |   /**
> > |    * kstrtoull - convert a string to an unsigned long long
> > |    * @s: The start of the string. The string must be null-terminated, and may also
> > |    *  include a single newline before its terminating null. The first character
> > |    ...
> >
> > Let's remove the redundant functionality and let kstrtouint handle it.
> >
> > Link: https://github.com/KSPP/linux/issues/90
> > Cc: linux-hardening@vger.kernel.org
> > Suggested-by: Kees Cook <keescook@chromium.org>
> > Signed-off-by: Justin Stitt <justinstitt@google.com>
>
> This looks much cleaner. Thanks!
>
> Reviewed-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Chen-Yu Tsai <wens@csie.org>