netdev - Re: [PATCH iwl-next v7 5/9] igc: Add support for frame preemption verification

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250304152644.y7j7eshr4qxhmxq2@skbuf>
Date: Tue, 4 Mar 2025 17:26:44 +0200
From: Vladimir Oltean <vladimir.oltean@....com>
To: Faizal Rahim <faizal.abdul.rahim@...ux.intel.com>
Cc: Tony Nguyen <anthony.l.nguyen@...el.com>,
	Przemek Kitszel <przemyslaw.kitszel@...el.com>,
	Andrew Lunn <andrew+netdev@...n.ch>,
	"David S . Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Maxime Coquelin <mcoquelin.stm32@...il.com>,
	Alexandre Torgue <alexandre.torgue@...s.st.com>,
	Simon Horman <horms@...nel.org>,
	Russell King <linux@...linux.org.uk>,
	Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Jesper Dangaard Brouer <hawk@...nel.org>,
	John Fastabend <john.fastabend@...il.com>,
	Furong Xu <0x1207@...il.com>,
	Russell King <rmk+kernel@...linux.org.uk>,
	Serge Semin <fancer.lancer@...il.com>,
	Xiaolei Wang <xiaolei.wang@...driver.com>,
	Suraj Jaiswal <quic_jsuraj@...cinc.com>,
	Kory Maincent <kory.maincent@...tlin.com>,
	Gal Pressman <gal@...dia.com>,
	Jesper Nilsson <jesper.nilsson@...s.com>,
	Andrew Halaney <ahalaney@...hat.com>,
	Choong Yong Liang <yong.liang.choong@...ux.intel.com>,
	Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>,
	Vinicius Costa Gomes <vinicius.gomes@...el.com>,
	intel-wired-lan@...ts.osuosl.org, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-stm32@...md-mailman.stormreply.com,
	linux-arm-kernel@...ts.infradead.org, bpf@...r.kernel.org
Subject: Re: [PATCH iwl-next v7 5/9] igc: Add support for frame preemption
 verification

On Mon, Mar 03, 2025 at 05:26:54AM -0500, Faizal Rahim wrote:
> +static inline bool igc_fpe_is_verify_or_response(union igc_adv_rx_desc *rx_desc,
> +						 unsigned int size)
> +{
> +	u32 status_error = le32_to_cpu(rx_desc->wb.upper.status_error);
> +	int smd;
> +
> +	smd = FIELD_GET(IGC_RXDADV_STAT_SMD_TYPE_MASK, status_error);
> +
> +	return (smd == IGC_RXD_STAT_SMD_TYPE_V || smd == IGC_RXD_STAT_SMD_TYPE_R) &&
> +		size == SMD_FRAME_SIZE;
> +}

The NIC should explicitly not respond to frames which have an SMD-V but
are not "verify" mPackets (7 octets of 0x55 + 1 octet SMD-V + 60 octets
of 0x00 + mCRC - as per 802.3 definitions). Similarly, it should only
treat SMD-R frames which contain 7 octets of 0x55 + 1 octet SMD-R + 60
octets of 0x00 + mCRC as "respond" mPackets, and only advance its
verification state machine based on those.

Specifically, it doesn't look like you are ensuring the packet payload
contains 60 octets of zeroes. Is this something that the hardware
already does for you, or is it something that needs further validation
and differentiation in software?