From: Aaron Conole <aconole@redhat.com>
To: Eric Dumazet <edumazet@kernel.org>
Cc: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Paolo Abeni <pabeni@redhat.com>,
Willem de Bruijn <willemb@google.com>,
Simon Horman <horms@kernel.org>,
netdev@vger.kernel.org, Andrew Lunn <andrew+netdev@lunn.ch>,
Eelco Chaudron <echaudro@redhat.com>,
Ilya Maximets <i.maximets@ovn.org>,
Jamal Hadi Salim <jhs@mojatatu.com>,
Jiri Pirko <jiri@resnulli.us>,
dev@openvswitch.org,
Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
Ren Wei <weir@nebusec.ai>
Subject: Re: [PATCH net 1/5] net: add eth_type_trans_careful()
Date: Tue, 27 Oct 2026 09:51:58 -0400 [thread overview]
Message-ID: <f7t33trs135.fsf@aconole-thinkpadt14gen4.rmtusnh.csb> (raw)
In-Reply-To: <20261027082604.1485903-2-edumazet@kernel.org> (Eric Dumazet's message of "Tue, 27 Oct 2026 09:26:00 +0100")
Eric Dumazet <edumazet@kernel.org> writes:
> eth_type_trans() assumes ETH_HLEN bytes are present in skb->head.
> NIC drivers always provide this, and they should keep using the fast
> version.
>
> Devices looping skbs from their transmit path back to their receive
> path get skbs built by the stack instead. Their link-layer header
> might have been popped by tc actions (act_vlan pop_eth, act_ife decode)
> or OVS actions (pop_eth + pop_mpls / pop_nsh), leaving fewer than
> ETH_HLEN bytes in the linear part. eth_type_trans() then hits
> the BUG() in __skb_pull().
>
> Add eth_type_trans_careful(), which first pulls the Ethernet header,
> and returns a drop reason on failure, so that the few devices exposed
> to this can drop such packets.
>
> Signed-off-by: Eric Dumazet <edumazet@kernel.org>
> ---
Reviewed-by: Aaron Conole <aconole@redhat.com>
next prev parent reply other threads:[~2026-10-27 13:52 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-27 8:25 [PATCH net 0/5] net: fix eth_type_trans() crashes on skbs coming from the stack Eric Dumazet
2026-10-27 8:26 ` [PATCH net 1/5] net: add eth_type_trans_careful() Eric Dumazet
2026-10-27 13:51 ` Aaron Conole [this message]
2026-10-27 15:02 ` Willem de Bruijn
2026-10-27 8:26 ` [PATCH net 2/5] loopback: use eth_type_trans_careful() Eric Dumazet
2026-10-27 8:26 ` [PATCH net 3/5] net: use eth_type_trans_careful() in __dev_forward_skb2() Eric Dumazet
2026-10-27 8:26 ` [PATCH net 4/5] openvswitch: use eth_type_trans_careful() in internal_dev_recv() Eric Dumazet
2026-10-27 13:50 ` Aaron Conole
2026-10-27 8:26 ` [PATCH net 5/5] net/sched: act_ife: do not consume the inner header on egress Eric Dumazet
2026-10-27 9:17 ` [PATCH net 0/5] net: fix eth_type_trans() crashes on skbs coming from the stack Jamal Hadi Salim
2026-10-27 9:51 ` Eric Dumazet
2026-10-27 13:07 ` Jamal Hadi Salim
2026-10-27 14:00 ` Aaron Conole
2026-10-27 14:33 ` Eric Dumazet
2026-10-27 14:40 ` Willem de Bruijn
2026-10-27 15:49 ` Eric Dumazet
2026-10-27 19:48 ` Jamal Hadi Salim
2026-10-27 20:34 ` Eric Dumazet
2026-10-27 21:20 ` Jamal Hadi Salim
2026-10-27 21:25 ` Jakub Kicinski
2026-10-28 5:02 ` Eric Dumazet
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