Re: [PATCH net] net: drop bad gso csum_start and offset in virtio_net_hdr

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Aug 26, 2024 at 10:07:50PM +0200, Salvatore Bonaccorso wrote:
> 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@debian.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")

Ah, that works, thanks!

greg k-h