From: Andrew Lunn <andrew@lunn.ch>
To: Kees Cook <kees@kernel.org>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>,
Claudiu Beznea <claudiu.beznea@tuxon.dev>,
Andrew Lunn <andrew+netdev@lunn.ch>,
"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: macb: Truncate TX1519CNT for trailing NUL
Date: Tue, 11 Mar 2025 15:12:00 +0100 [thread overview]
Message-ID: <64b35f60-2ed4-4ab0-8f4e-0dba042b4d4d@lunn.ch> (raw)
In-Reply-To: <20250310222415.work.815-kees@kernel.org>
On Mon, Mar 10, 2025 at 03:24:16PM -0700, Kees Cook wrote:
> GCC 15's -Wunterminated-string-initialization saw that this string was
> being truncated. Adjust the initializer so that the needed final NUL
> character will be present.
This is where we get into the ugliness of the ethtool API for strings.
It is not actually NUL terminated. The code uses memcpy(), see:
https://elixir.bootlin.com/linux/v6.13.6/source/drivers/net/ethernet/cadence/macb_main.c#L3193
The kAPI is that userspace provides a big buffer, and the kernel then
copies these strings into the buffer at 32 byte offsets. There is no
requirement for a NUL between them since they are all 32 bytes long.
Andrew
next prev parent reply other threads:[~2025-03-11 14:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-10 22:24 [PATCH] net: macb: Truncate TX1519CNT for trailing NUL Kees Cook
2025-03-11 7:27 ` Michal Swiatkowski
2025-03-11 22:38 ` Kees Cook
2025-03-11 14:12 ` Andrew Lunn [this message]
2025-03-11 22:41 ` Kees Cook
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