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Message-ID: <128f5692-982a-7bba-d9b3-174881cba49e@intel.com>
Date:   Tue, 10 Oct 2023 14:22:12 -0700
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Subject: Re: [PATCH] igc: replace deprecated strncpy with strscpy
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To:     Justin Stitt <justinstitt@google.com>,
        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>
CC:     <intel-wired-lan@lists.osuosl.org>, <netdev@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <linux-hardening@vger.kernel.org>
References: <20231010-strncpy-drivers-net-ethernet-intel-igc-igc_main-c-v1-1-f1f507ecc476@google.com>
From:   Jesse Brandeburg <jesse.brandeburg@intel.com>
In-Reply-To: <20231010-strncpy-drivers-net-ethernet-intel-igc-igc_main-c-v1-1-f1f507ecc476@google.com>
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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 format
> 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 = alloc_etherdev_mq(sizeof(struct igc_adapter),
> |                                  IGC_MAX_TX_QUEUES);
> ...
> alloc_etherdev() -> alloc_etherdev_mq() -> alloc_etherdev_mqs() ->
> alloc_netdev_mqs() ...
> |       p = kvzalloc(alloc_size, GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL);
> 
> 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.