Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.32 as permitted sender) client-ip=23.128.96.32;
Date:   Mon, 9 Oct 2023 12:58:32 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Justin Stitt <justinstitt@google.com>
Cc:     Rasesh Mody <rmody@marvell.com>,
        Sudarsana Kalluru <skalluru@marvell.com>,
        GR-Linux-NIC-Dev@marvell.com,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH v2] bna: replace deprecated strncpy with strscpy_pad
Message-ID: <202310091258.C4CDBBED7D@keescook>
References: <20231009-strncpy-drivers-net-ethernet-brocade-bna-bfa_ioc-c-v2-1-78e0f47985d3@google.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20231009-strncpy-drivers-net-ethernet-brocade-bna-bfa_ioc-c-v2-1-78e0f47985d3@google.com>
Precedence: bulk

On Mon, Oct 09, 2023 at 05:45:33PM +0000, Justin Stitt 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.
> 
> bfa_ioc_get_adapter_manufacturer() simply copies a string literal into
> `manufacturer`.
> 
> Another implementation of bfa_ioc_get_adapter_manufacturer() from
> drivers/scsi/bfa/bfa_ioc.c uses memset + strscpy:
> |	void
> |	bfa_ioc_get_adapter_manufacturer(struct bfa_ioc_s *ioc, char *manufacturer)
> |	{
> |		memset((void *)manufacturer, 0, BFA_ADAPTER_MFG_NAME_LEN);
> |			strscpy(manufacturer, BFA_MFG_NAME, BFA_ADAPTER_MFG_NAME_LEN);
> |	}
> 
> Let's use `strscpy_pad` to eliminate some redundant work while still
> NUL-terminating and NUL-padding the destination buffer.
> 
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
> Link: https://github.com/KSPP/linux/issues/90
> Cc: linux-hardening@vger.kernel.org
> Signed-off-by: Justin Stitt <justinstitt@google.com>

Thanks for the update! Yeah, this looks safe to me now.

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook