From: Simon Horman <horms@kernel.org>
To: Ren Wei <n05ec@lzu.edu.cn>
Cc: netdev@vger.kernel.org, jhs@mojatatu.com, jiri@resnulli.us,
davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, elibr@mellanox.com, yifanwucs@gmail.com,
tomapufckgml@gmail.com, yuantan098@gmail.com, bird@lzu.edu.cn,
enjou1224z@gmail.com, caoruide123@gmail.com
Subject: Re: [PATCH net 1/1] net: sched: act_csum: validate nested VLAN headers
Date: Fri, 3 Apr 2026 17:26:23 +0100 [thread overview]
Message-ID: <20260403162623.GP113102@horms.kernel.org> (raw)
In-Reply-To: <22df2fcb49f410203eafa5d97963dd36089f4ecf.1774892775.git.caoruide123@gmail.com>
On Thu, Apr 02, 2026 at 10:46:20PM +0800, Ren Wei wrote:
> From: Ruide Cao <caoruide123@gmail.com>
>
> tcf_csum_act() walks nested VLAN headers directly from skb->data when an
> skb still carries in-payload VLAN tags. The current code reads
> vlan->h_vlan_encapsulated_proto and then pulls VLAN_HLEN bytes without
> first ensuring that the full VLAN header is present in the linear area.
>
> If only part of an inner VLAN header is linearized, accessing
> h_vlan_encapsulated_proto reads past the linear area, and the following
> skb_pull(VLAN_HLEN) may violate skb invariants.
>
> Fix this by requiring pskb_may_pull(skb, VLAN_HLEN) before accessing and
> pulling each nested VLAN header. If the header still is not fully
> available, drop the packet through the existing error path.
>
> Fixes: 2ecba2d1e45b ("net: sched: act_csum: Fix csum calc for tagged packets")
> Reported-by: Yifan Wu <yifanwucs@gmail.com>
> Reported-by: Juefei Pu <tomapufckgml@gmail.com>
> Co-developed-by: Yuan Tan <yuantan098@gmail.com>
> Signed-off-by: Yuan Tan <yuantan098@gmail.com>
> Suggested-by: Xin Liu <bird@lzu.edu.cn>
> Tested-by: Ren Wei <enjou1224z@gmail.com>
> Signed-off-by: Ruide Cao <caoruide123@gmail.com>
> Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Reviewed-by: Simon Horman <horms@kernel.org>
next prev parent reply other threads:[~2026-04-03 16:26 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1774892775.git.caoruide123@gmail.com>
2026-04-02 14:46 ` [PATCH net 1/1] net: sched: act_csum: validate nested VLAN headers Ren Wei
2026-04-03 16:26 ` Simon Horman [this message]
2026-04-03 22:00 ` patchwork-bot+netdevbpf
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