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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Thu, 28 Sep 2023 23:44:53 +0200
Message-ID: <CACRpkdaPvDFvxSVHeLZ3Bxx5yVH3LN1OOpGm78cJ+wp7q3C+Vw@mail.gmail.com>
Subject: Re: [PATCH] mfd: db8500-prcmu: replace deprecated strncpy with strscpy
To:     Justin Stitt <justinstitt@google.com>
Cc:     Lee Jones <lee@kernel.org>, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
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Hi Justin,

thanks for your patch!

On Wed, Sep 27, 2023 at 7:10=E2=80=AFAM Justin Stitt <justinstitt@google.co=
m> wrote:

> `strncpy` is deprecated for use on NUL-terminated destination strings
> [1] and as such we should prefer more robust and less ambiguous string
> interfaces.
>
> We expect project_name to be NUL-terminated based on its use with
> pr_info:
> |       pr_info("PRCMU firmware: %s(%d), version %d.%d.%d\n",
> |               fw_info.version.project_name,
> |               fw_info.version.project,
> |               fw_info.version.api_version,
> |               fw_info.version.func_version,
> |               fw_info.version.errata);
>
> Moreover, NUL-padding does not seem to be needed.
>
> Considering the above, a suitable replacement is `strscpy` [2] due to
> the fact that it guarantees NUL-termination on the destination buffer
> without unnecessarily NUL-padding.
>
> Let's also change `PRCMU_FW_PROJECT_NAME_LEN` to just
> sizeof(fw_info.version.project_name) as this is more idiomatic strscpy
> usage.
>
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strn=
cpy-on-nul-terminated-strings [1]
> Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.h=
tml [2]
> Link: https://github.com/KSPP/linux/issues/90
> Cc: linux-hardening@vger.kernel.org
> Signed-off-by: Justin Stitt <justinstitt@google.com>

Well analyzed, well patched, what can I say! Hats off.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij