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Message-ID: <19f84dd5-e769-aca9-a8ea-89008bfd9226@intel.com>
Date:   Tue, 10 Oct 2023 14:21:34 -0700
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Subject: Re: [PATCH] i40e: use scnprintf over strncpy+strncat
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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-i40e-i40e_ddp-c-v1-1-f01a23394eab@google.com>
From:   Jesse Brandeburg <jesse.brandeburg@intel.com>
In-Reply-To: <20231010-strncpy-drivers-net-ethernet-intel-i40e-i40e_ddp-c-v1-1-f01a23394eab@google.com>
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On 10/10/2023 1:53 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.
> 
> Moreover, `strncat` shouldn't really be used either as per
> fortify-string.h:
>  * Do not use this function. While FORTIFY_SOURCE tries to avoid
>  * read and write overflows, this is only possible when the sizes
>  * of @p and @q are known to the compiler. Prefer building the
>  * string with formatting, via scnprintf() or similar.
> 
> Instead, use `scnprintf` with "%s%s" format string. This code is now
> more readable and robust.


Please see my comments on the igbvf patch.