Re: [PATCH net-next 0/7] net: intel: replace deprecated strncpy uses

From: Kees Cook <keescook@chromium.org>
To: Justin Stitt <justinstitt@google.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.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>,
	linux-hardening@vger.kernel.org,
	intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next 0/7] net: intel: replace deprecated strncpy uses
Date: Tue, 10 Oct 2023 16:31:32 -0700	[thread overview]
Message-ID: <202310101630.AB35100@keescook> (raw)
In-Reply-To: <20231010-netdev-replace-strncpy-resend-as-series-v1-0-caf9f0f2f021@google.com>

On Tue, Oct 10, 2023 at 10:26:53PM +0000, Justin Stitt wrote:
> Hi,
> 
> This series aims to eliminate uses of strncpy() as it is a deprecated
> interface [1] with many viable replacements available.
> 
> Predominantly, strscpy() is the go-to replacement as it guarantees
> NUL-termination on the destination buffer (which strncpy does not). With
> that being said, I did not identify any buffer overread problems as the
> size arguments were carefully measured to leave room for trailing
> NUL-bytes. Nonetheless, we should favor more robust and less ambiguous
> interfaces.
> 
> Previously, each of these patches was sent individually at:
> 1) https://lore.kernel.org/all/20231009-strncpy-drivers-net-ethernet-intel-e100-c-v1-1-ca0ff96868a3@google.com/
> 2) https://lore.kernel.org/all/20231010-strncpy-drivers-net-ethernet-intel-e1000-e1000_main-c-v1-1-b1d64581f983@google.com/
> 3) https://lore.kernel.org/all/20231010-strncpy-drivers-net-ethernet-intel-fm10k-fm10k_ethtool-c-v1-1-dbdc4570c5a6@google.com/
> 4) https://lore.kernel.org/all/20231010-strncpy-drivers-net-ethernet-intel-i40e-i40e_ddp-c-v1-1-f01a23394eab@google.com/
> 5) https://lore.kernel.org/all/20231010-strncpy-drivers-net-ethernet-intel-igb-igb_main-c-v1-1-d796234a8abf@google.com/
> 6) https://lore.kernel.org/all/20231010-strncpy-drivers-net-ethernet-intel-igbvf-netdev-c-v1-1-69ccfb2c2aa5@google.com/
> 7) https://lore.kernel.org/all/20231010-strncpy-drivers-net-ethernet-intel-igc-igc_main-c-v1-1-f1f507ecc476@google.com/
> 
> Consider these dead as this series is their new home :)
> 
> I found all these instances with: $ rg "strncpy\("
> 
> This series may collide in a not-so-nice way with [3]. This series can
> go in after that one with a rebase. I'll send a v2 if necessary.
> 
> [3]: https://lore.kernel.org/netdev/20231003183603.3887546-1-jesse.brandeburg@intel.com/
> 
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
> Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
> Link: https://github.com/KSPP/linux/issues/90
> Signed-off-by: Justin Stitt <justinstitt@google.com>
> ---
> Justin Stitt (7):
>       e100: replace deprecated strncpy with strscpy
>       e1000: replace deprecated strncpy with strscpy
>       fm10k: replace deprecated strncpy with strscpy
>       i40e: use scnprintf over strncpy+strncat
>       igb: replace deprecated strncpy with strscpy
>       igbvf: replace deprecated strncpy with strscpy
>       igc: replace deprecated strncpy with strscpy

These all look good to me. Thanks for the careful analysis!

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

-Kees

-- 
Kees Cook