From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Jakub Kicinski <kuba@kernel.org>,
Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>,
Sean Anderson <sean.anderson@linux.dev>,
"David S . Miller" <davem@davemloft.net>,
Paolo Abeni <pabeni@redhat.com>,
netdev@vger.kernel.org, Willem de Bruijn <willemb@google.com>,
linux-kernel@vger.kernel.org, Shuah Khan <shuah@kernel.org>,
linux-kselftest@vger.kernel.org
Subject: Re: [PATCH net] selftests: net: csum: Fix checksums for packets with non-zero padding
Date: Mon, 09 Sep 2024 21:01:33 -0400 [thread overview]
Message-ID: <66df9a6d42871_81fd3294e8@willemb.c.googlers.com.notmuch> (raw)
In-Reply-To: <20240909165116.1bdb4757@kernel.org>
Jakub Kicinski wrote:
> On Mon, 09 Sep 2024 13:26:42 -0400 Willem de Bruijn wrote:
> > > This seems to be a bug in the driver.
> > >
> > > A call to skb_put_padto(skb, ETH_ZLEN) should be added.
> >
> > In which case this test detecting it may be nice to have, for lack of
> > a more targeted test.
>
> IIUC we're basically saying that we don't need to trim because pad
> should be 0? In that case maybe let's keep the patch but add a check
> on top which scans the pad for non-zero bytes, and print an informative
> warning?
Data arriving with padding probably deserves a separate test.
We can use this csum test as stand-in, I suppose.
Is it safe to assume that all padding is wrong on ingress, not just
non-zero padding. The ip stack itself treats it as benign and trims
the trailing bytes silently.
I do know of legitimate cases of trailer data lifting along.
next prev parent reply other threads:[~2024-09-10 1:01 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-06 21:07 [PATCH net] selftests: net: csum: Fix checksums for packets with non-zero padding Sean Anderson
2024-09-07 2:05 ` Willem de Bruijn
2024-09-09 15:02 ` Sean Anderson
2024-09-09 15:06 ` Willem de Bruijn
2024-09-09 15:09 ` Eric Dumazet
2024-09-09 17:26 ` Willem de Bruijn
2024-09-09 23:51 ` Jakub Kicinski
2024-09-10 1:01 ` Willem de Bruijn [this message]
2024-09-10 14:29 ` Sean Anderson
2024-09-10 17:42 ` Willem de Bruijn
2024-09-10 17:52 ` Sean Anderson
2024-09-10 21:01 ` Willem de Bruijn
2024-09-11 0:00 ` patchwork-bot+netdevbpf
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