netdev - Re: [PATCH net v2 1/1] net: stmmac: Prevent DSA tags from breaking COE on stmmac

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: <CACRpkdZjOBpD6HoobgMBA27dS+uz5pqb8otL+fGtMvsywYBTPA@mail.gmail.com>
Date: Tue, 2 Jan 2024 21:27:20 +0100
From: Linus Walleij <linus.walleij@...aro.org>
To: Romain Gantois <romain.gantois@...tlin.com>
Cc: Alexandre Torgue <alexandre.torgue@...s.st.com>, Jose Abreu <joabreu@...opsys.com>, 
	"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>, Miquel Raynal <miquel.raynal@...tlin.com>, 
	Maxime Chevallier <maxime.chevallier@...tlin.com>, Sylvain Girard <sylvain.girard@...com>, 
	Vladimir Oltean <olteanv@...il.com>, Andrew Lunn <andrew@...n.ch>, 
	Pascal EBERHARD <pascal.eberhard@...com>, Richard Tresidder <rtresidd@...ctromag.com.au>, 
	netdev@...r.kernel.org, linux-stm32@...md-mailman.stormreply.com, 
	linux-arm-kernel@...ts.infradead.org, stable@...r.kernel.org
Subject: Re: [PATCH net v2 1/1] net: stmmac: Prevent DSA tags from breaking
 COE on stmmac

Hi Romain,

overall this patch makes sense.

On Tue, Jan 2, 2024 at 5:27 PM Romain Gantois
<romain.gantois@...tlin.com> wrote:

> Some DSA tagging protocols change the EtherType field in the MAC header
> e.g.  DSA_TAG_PROTO_(DSA/EDSA/BRCM/MTK/RTL4C_A/SJA1105). On TX these tagged
> frames are ignored by the checksum offload engine and IP header checker of
> some stmmac cores.
>
> On RX, the stmmac driver wrongly assumes that checksums have been computed
> for these tagged packets, and sets CHECKSUM_UNNECESSARY.
>
> Add an additional check in the stmmac tx and rx hotpaths so that COE is
> deactivated for packets with ethertypes that will not trigger the COE and
> ip header checks.
>
> Fixes: 6b2c6e4a938f ("net: stmmac: propagate feature flags to vlan")
> Cc: stable@...r.kernel.org
> Reported-by: Richard Tresidder <rtresidd@...ctromag.com.au>
> Closes: https://lore.kernel.org/netdev/e5c6c75f-2dfa-4e50-a1fb-6bf4cdb617c2@electromag.com.au/
> Reported-by: Romain Gantois <romain.gantois@...tlin.com>
> Closes: https://lore.kernel.org/netdev/c57283ed-6b9b-b0e6-ee12-5655c1c54495@bootlin.com/
> Signed-off-by: Romain Gantois <romain.gantois@...tlin.com>
(...)

> +static inline bool stmmac_has_ip_ethertype(struct sk_buff *skb)
> +{
> +       __be16 proto = eth_header_parse_protocol(skb);

I made a new function for this in my patch
https://lore.kernel.org/netdev/20231222-new-gemini-ethernet-regression-v4-2-a36e71b0f32b@linaro.org/

I was careful to add if (!pskb_may_pull(skb, ETH_HLEN)) because Eric
was very specific about this, I suppose you could get fragment frames that
are smaller than an ethernet header.

I should use eth_header_parse_protocol() instead of reimplementing it
though. :/

Should we add an if (!pskb_may_pull(skb, ETH_HLEN)) to
eth_header_parse_protocol()?

Yours,
Linus Walleij