linux-kernel - RE: [EXTERNAL] Re: [PATCH v3] hv_netvsc: Set VF priv_flags to IFF_NO_ADDRCONF before open to prevent IPv6 addrconf

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID:
 <SN6PR2101MB0943EAAB55E0BF97E0841419CA56A@SN6PR2101MB0943.namprd21.prod.outlook.com>
Date: Wed, 16 Jul 2025 16:15:42 +0000
From: Haiyang Zhang <haiyangz@...rosoft.com>
To: Xin Long <lucien.xin@...il.com>, Simon Horman <horms@...nel.org>
CC: Li Tian <litian@...hat.com>, "netdev@...r.kernel.org"
	<netdev@...r.kernel.org>, "linux-hyperv@...r.kernel.org"
	<linux-hyperv@...r.kernel.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, Dexuan Cui <decui@...rosoft.com>, Stephen
 Hemminger <stephen@...workplumber.org>, Long Li <longli@...rosoft.com>
Subject: RE: [EXTERNAL] Re: [PATCH v3] hv_netvsc: Set VF priv_flags to
 IFF_NO_ADDRCONF before open to prevent IPv6 addrconf



> -----Original Message-----
> From: Xin Long <lucien.xin@...il.com>
> Sent: Wednesday, July 16, 2025 11:14 AM
> To: Simon Horman <horms@...nel.org>
> Cc: Li Tian <litian@...hat.com>; netdev@...r.kernel.org; linux-
> hyperv@...r.kernel.org; linux-kernel@...r.kernel.org; Haiyang Zhang
> <haiyangz@...rosoft.com>; Dexuan Cui <decui@...rosoft.com>; Stephen
> Hemminger <stephen@...workplumber.org>; Long Li <longli@...rosoft.com>
> Subject: [EXTERNAL] Re: [PATCH v3] hv_netvsc: Set VF priv_flags to
> IFF_NO_ADDRCONF before open to prevent IPv6 addrconf
>
> On Wed, Jul 16, 2025 at 5:29 AM Simon Horman <horms@...nel.org> wrote:
> >
> > + Xin Long
> >
> Thanks for Ccing me.
>
> > On Wed, Jul 16, 2025 at 08:26:05AM +0800, Li Tian wrote:
> > > Set an additional flag IFF_NO_ADDRCONF to prevent ipv6 addrconf.
> > >
> > > Commit under Fixes added a new flag change that was not made
> > > to hv_netvsc resulting in the VF being assinged an IPv6.
> > >
> > > Fixes: 8a321cf7becc ("net: add IFF_NO_ADDRCONF and use it in bonding
> to prevent ipv6 addrconf")
> > > Suggested-by: Cathy Avery <cavery@...hat.com>
> > > Signed-off-by: Li Tian <litian@...hat.com>
> > > ---
> > > v3:
> > >   - only fixes commit message.
> > > v2:
> https://lore.ker/
> nel.org%2Fnetdev%2F20250710024603.10162-1-
> litian%40redhat.com%2F&data=05%7C02%7Chaiyangz%40microsoft.com%7C80485948c
> b344b12f2dd08ddc47b7c6e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C63888
> 2756868249313%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAu
> MDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdat
> a=1ljWIFtnhAiGjdIEgNNlQZGK%2F%2FZHdgHVkvyCWY9%2BKxI%3D&reserved=0
> > >   - instead of replacing flag, add it.
> > > v1:
> https://lore.ker/
> nel.org%2Fnetdev%2F20250710024603.10162-1-
> litian%40redhat.com%2F&data=05%7C02%7Chaiyangz%40microsoft.com%7C80485948c
> b344b12f2dd08ddc47b7c6e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C63888
> 2756868272381%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAu
> MDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdat
> a=o%2B2BM9YEi3O2zcqQu9KfPae6PZerBWO%2FhL5KCIeJ9xI%3D&reserved=0
> > > ---
> > >  drivers/net/hyperv/netvsc_drv.c | 5 ++++-
> > >  1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > Hi Li Tian,
> >
> > Thanks for addressing earlier feedback.
> >
> > I don't think you need to repost because of this, but for future
> reference:
> >
> > 1. Because this is a fix for a commit that is present in net
> >    it should be targeted at that tree.
> >
> >    Subject: [PATCH net vX] ...
> >
> > 2. Please use get_maintainers.pl this.patch to generate the CC list. In
> >    this case Xin Long (now CCed) should be included as he is the author
> of the
> >    patch cited in the Fixes tag.
> >
> >    b4 can help you with this and other aspects of patch management.
> >
> > >
> > > diff --git a/drivers/net/hyperv/netvsc_drv.c
> b/drivers/net/hyperv/netvsc_drv.c
> > > index c41a025c66f0..8be9bce66a4e 100644
> > > --- a/drivers/net/hyperv/netvsc_drv.c
> > > +++ b/drivers/net/hyperv/netvsc_drv.c
> > > @@ -2317,8 +2317,11 @@ static int netvsc_prepare_bonding(struct
> net_device *vf_netdev)
> > >       if (!ndev)
> > >               return NOTIFY_DONE;
> > >
> > > -     /* set slave flag before open to prevent IPv6 addrconf */
> > > +     /* Set slave flag and no addrconf flag before open
> > > +      * to prevent IPv6 addrconf.
> > > +      */
> > >       vf_netdev->flags |= IFF_SLAVE;
> > > +     vf_netdev->priv_flags |= IFF_NO_ADDRCONF;
> If it is only to prevent IPv6 addrconf, I think you can replace IFF_SLAVE
> with IFF_NO_ADDRCONF.
>
> IFF_SLAVE normally comes with IFF_MASTER, like bonding and eql.
> I don't see IFF_MASTER used in netvsc_drv.c, so IFF_SLAVE probably
> should be dropped, including the one in __netvsc_vf_setup()?

The IFF_SLAVE is not just for ipv6, the comment should be updated.
IFF_SLAVE is also used by udev and our other user mode daemons, so it needs
to stay.

- Haiyang