netdev - Re: [PATCH net] net: drop bad gso csum_start and offset in virtio_net

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Message-ID: <ZszgliPW3QEodr5G@eldamar.lan>
Date: Mon, 26 Aug 2024 22:07:50 +0200
From: Salvatore Bonaccorso <carnil@...ian.org>
To: Willem de Bruijn <willemdebruijn.kernel@...il.com>
Cc: Vitaly Chikunov <vt@...linux.org>,
	Christian Heusel <christian@...sel.eu>,
	Adrian Vladu <avladu@...udbasesolutions.com>,
	"Michael S. Tsirkin" <mst@...hat.com>,
	Greg KH <gregkh@...uxfoundation.org>,
	"alexander.duyck@...il.com" <alexander.duyck@...il.com>,
	"arefev@...mel.ru" <arefev@...mel.ru>,
	"davem@...emloft.net" <davem@...emloft.net>,
	"edumazet@...gle.com" <edumazet@...gle.com>,
	"jasowang@...hat.com" <jasowang@...hat.com>,
	"kuba@...nel.org" <kuba@...nel.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"pabeni@...hat.com" <pabeni@...hat.com>,
	"stable@...r.kernel.org" <stable@...r.kernel.org>,
	"willemb@...gle.com" <willemb@...gle.com>,
	"regressions@...ts.linux.dev" <regressions@...ts.linux.dev>,
	David Prévot <taffit@...ian.org>
Subject: Re: [PATCH net] net: drop bad gso csum_start and offset in
 virtio_net_hdr

Hi,

On Mon, Aug 26, 2024 at 04:10:21PM +0200, Salvatore Bonaccorso wrote:
> Hi,
> 
> On Wed, Aug 21, 2024 at 10:05:12AM -0400, Willem de Bruijn wrote:
> > Vitaly Chikunov wrote:
> > > Willem,
> > > 
> > > On Wed, Aug 14, 2024 at 09:53:58AM GMT, Willem de Bruijn wrote:
> > > > Christian Heusel wrote:
> > > > > On 24/08/14 10:10AM, Adrian Vladu wrote:
> > > > > > Hello,
> > > > > > 
> > > > > > The 6.6.y branch has the patch already in the stable queue -> https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/commit/?id=3e713b73c01fac163a5c8cb0953d1e300407a773, and it should be available in the 6.6.46 upcoming minor.
> > > > > > 
> > > > > > Thanks, Adrian.
> > > > > 
> > > > > Yeah it's also queued up for 6.10, which I both missed (sorry for that!).
> > > > > If I'm able to properly backport the patch for 6.1 I'll send that one,
> > > > > but my hopes are not too high that this will work ..
> > > > 
> > > > There are two conflicts.
> > > > 
> > > > The one in include/linux/virtio_net.h is resolved by first backporting
> > > > commit fc8b2a6194693 ("net: more strict VIRTIO_NET_HDR_GSO_UDP_L4
> > > > validation")
> > > > 
> > > > We did not backport that to stable because there was some slight risk
> > > > that applications might be affected. This has not surfaced.
> > > > 
> > > > The conflict in net/ipv4/udp_offload.c is not so easy to address.
> > > > There were lots of patches between v6.1 and linus/master, with far
> > > > fewer of these betwee v6.1 and linux-stable/linux-6.1.y.
> > > 
> > > BTW, we successfully cherry-picked 3 suggested[1] commits over v6.1.105 in
> > > ALT, and there is no reported problems as of yet.
> > > 
> > >   89add40066f9 ("net: drop bad gso csum_start and offset in virtio_net_hdr")
> > >   fc8b2a619469 ("net: more strict VIRTIO_NET_HDR_GSO_UDP_L4 validation")
> > >   9840036786d9 ("gso: fix dodgy bit handling for GSO_UDP_L4")
> > > 
> > > [1] https://lore.kernel.org/all/2024081147-altitude-luminous-19d1@gregkh/
> > 
> > That's good to hear.
> > 
> > These are all fine to go to 6.1 stable.
> 
> FWIW, as we are hit by this issue for Debian bookworm, we have testing
> as well from David Prévot <taffit@...ian.org>, cf. the report in
> https://bugs.debian.org/1079684 .
> 
> He mentions that the 9840036786d9 ("gso: fix dodgy bit handling for
> GSO_UDP_L4") patch does not apply cleanly, looks to be because of
> 1fd54773c267 ("udp: allow header check for dodgy GSO_UDP_L4 packets.")
> from 6.2-rc1, which are reverted in the commit.

Just to give an additional confirmation: Applying

1fd54773c267 ("udp: allow header check for dodgy GSO_UDP_L4 packets.")
9840036786d9 ("gso: fix dodgy bit handling for GSO_UDP_L4")
fc8b2a619469 ("net: more strict VIRTIO_NET_HDR_GSO_UDP_L4 validation")
89add40066f9 ("net: drop bad gso csum_start and offset in virtio_net_hdr")

addresses the issue from

https://bugs.debian.org/1079684

matching

https://bugzilla.kernel.org/show_bug.cgi?id=219129

I tested it with the iperf3 based reproducers.

Tested-by: Salvatore Bonaccorso <carnil@...ian.org>

Regards,
Salvatore