From: Kees Cook <keescook@chromium•org>
To: Justin Stitt <justinstitt@google•com>
Cc: Chris Snook <chris.snook@gmail•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] net: atheros: replace deprecated strncpy with strscpy
Date: Wed, 4 Oct 2023 21:57:38 -0700 [thread overview]
Message-ID: <202310042157.D314C6D7EF@keescook> (raw)
In-Reply-To: <20231005-strncpy-drivers-net-ethernet-atheros-atlx-atl2-c-v1-1-493f113ebfc7@google.com>
On Thu, Oct 05, 2023 at 01:29:45AM +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.
>
> We expect netdev->name to be NUL-terminated based on its use with format
> strings and dev_info():
> | dev_info(&adapter->pdev->dev,
> | "%s link is up %d Mbps %s\n",
> | netdev->name, adapter->link_speed,
> | adapter->link_duplex == FULL_DUPLEX ?
> | "full duplex" : "half duplex");
>
> Furthermore, NUL-padding is not required as netdev is already
> zero-initialized through alloc_etherdev().
>
> 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.
>
> 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
> Cc: linux-hardening@vger•kernel.org
> Signed-off-by: Justin Stitt <justinstitt@google•com>
Looks right; destination length correctly updated.
Reviewed-by: Kees Cook <keescook@chromium•org>
--
Kees Cook
next prev parent reply other threads:[~2023-10-05 4:57 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-05 1:29 [PATCH] net: atheros: replace deprecated strncpy with strscpy Justin Stitt
2023-10-05 4:57 ` Kees Cook [this message]
2023-10-06 23:00 ` patchwork-bot+netdevbpf
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