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From: Andrei Vagin <avagin@gmail.com>
Date: Thu, 6 Jun 2024 15:16:56 -0700
Message-ID: <CANaxB-wSegSBot-8YCeiw-CsfdubRJMacC6nmRPLyoD4eGSc-w@mail.gmail.com>
Subject: Re: [PATCH net] gve: ignore nonrelevant GSO type bits when processing
 TSO headers
To: joshwash@google.com
Cc: netdev@vger.kernel.org, davem@davemloft.net, kuba@kernel.org, 
	stable@kernel.org, Praveen Kaligineedi <pkaligineedi@google.com>, 
	Harshitha Ramamurthy <hramamurthy@google.com>, Eric Dumazet <edumazet@google.com>, 
	Jeroen de Borst <jeroendb@google.com>, Shailend Chand <shailend@google.com>, 
	Paolo Abeni <pabeni@redhat.com>, Willem de Bruijn <willemb@google.com>, 
	Rushil Gupta <rushilg@google.com>, Catherine Sullivan <csully@google.com>, Bailey Forrest <bcf@google.com>, 
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On Thu, Jun 6, 2024 at 12:22=E2=80=AFPM <joshwash@google.com> wrote:
>
> From: Joshua Washington <joshwash@google.com>
>
> TSO currently fails when the skb's gso_type field has more than one bit
> set.
>
> TSO packets can be passed from userspace using PF_PACKET, TUNTAP and a
> few others, using virtio_net_hdr (e.g., PACKET_VNET_HDR). This includes
> virtualization, such as QEMU, a real use-case.

Here is the bug report where this issue was triggered by gVisor:
https://github.com/google/gvisor/issues/10344

>
> The gso_type and gso_size fields as passed from userspace in
> virtio_net_hdr are not trusted blindly by the kernel. It adds gso_type
> |=3D SKB_GSO_DODGY to force the packet to enter the software GSO stack
> for verification.
>
> This issue might similarly come up when the CWR bit is set in the TCP
> header for congestion control, causing the SKB_GSO_TCP_ECN gso_type bit
> to be set.
>
> Fixes: a57e5de476be ("gve: DQO: Add TX path")
>
> Signed-off-by: Joshua Washington <joshwash@google.com>
> Reviewed-by: Praveen Kaligineedi <pkaligineedi@google.com>
> Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
> Suggested-by: Eric Dumazet <edumazet@google.com>

Acked-by: Andrei Vagin <avagin@gmail.com>

Thanks,
Andrei