Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:2 as permitted sender) client-ip=2620:137:e000::3:2;
MIME-Version: 1.0
References: <20231010-strncpy-drivers-net-ethernet-intel-igc-igc_main-c-v1-1-f1f507ecc476@google.com>
 <128f5692-982a-7bba-d9b3-174881cba49e@intel.com>
In-Reply-To: <128f5692-982a-7bba-d9b3-174881cba49e@intel.com>
From:   Justin Stitt <justinstitt@google.com>
Date:   Tue, 10 Oct 2023 14:43:21 -0700
Message-ID: <CAFhGd8qE1oO0q91Y7sEq342qH1ty+KSMGUkczaQAJgghPBBX0w@mail.gmail.com>
Subject: Re: [PATCH] igc: replace deprecated strncpy with strscpy
To:     Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc:     Tony Nguyen <anthony.l.nguyen@intel.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Tue, Oct 10, 2023 at 2:22=E2=80=AFPM Jesse Brandeburg
<jesse.brandeburg@intel.com> wrote:
>
> On 10/10/2023 2:15 PM, 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.
> >
> > We expect netdev->name to be NUL-terminated based on its use with forma=
t
> > strings:
> > |       if (q_vector->rx.ring && q_vector->tx.ring)
> > |               sprintf(q_vector->name, "%s-TxRx-%u", netdev->name,
> >
> > Furthermore, we do not need NUL-padding as netdev is already
> > zero-allocated:
> > |       netdev =3D alloc_etherdev_mq(sizeof(struct igc_adapter),
> > |                                  IGC_MAX_TX_QUEUES);
> > ...
> > alloc_etherdev() -> alloc_etherdev_mq() -> alloc_etherdev_mqs() ->
> > alloc_netdev_mqs() ...
> > |       p =3D kvzalloc(alloc_size, GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAY=
FAIL);
> >
> > 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 opt for the more idiomatic strscpy usage of (dest, src,
> > sizeof(dest)) instead of (dest, src, SOME_LEN).
> >
>
>
> Please see my comments on the igbvf patch.

Ah, I sent too many before checking back in. I see
your comments now. Responded over there!

>
>
Thanks
Justin