netdev - Re: [PATCH net-next v9 06/11] net: ipv6: Use link netns in newlink() of rtnl_link

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] [day] [month] [year] [list]

Message-ID: <20250213110004.38415-1-kuniyu@amazon.com>
Date: Thu, 13 Feb 2025 20:00:04 +0900
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: <shaw.leon@...il.com>
CC: <alex.aring@...il.com>, <andrew+netdev@...n.ch>,
	<b.a.t.m.a.n@...ts.open-mesh.org>, <bpf@...r.kernel.org>,
	<bridge@...ts.linux.dev>, <davem@...emloft.net>, <donald.hunter@...il.com>,
	<dsahern@...nel.org>, <edumazet@...gle.com>, <herbert@...dor.apana.org.au>,
	<horms@...nel.org>, <kuba@...nel.org>, <kuniyu@...zon.com>,
	<linux-can@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-kselftest@...r.kernel.org>, <linux-ppp@...r.kernel.org>,
	<linux-rdma@...r.kernel.org>, <linux-wireless@...r.kernel.org>,
	<linux-wpan@...r.kernel.org>, <miquel.raynal@...tlin.com>,
	<netdev@...r.kernel.org>, <osmocom-net-gprs@...ts.osmocom.org>,
	<pabeni@...hat.com>, <shuah@...nel.org>, <stefan@...enfreihafen.org>,
	<steffen.klassert@...unet.com>, <wireguard@...ts.zx2c4.com>
Subject: Re: [PATCH net-next v9 06/11] net: ipv6: Use link netns in newlink() of rtnl_link_ops

From: Xiao Liang <shaw.leon@...il.com>
Date: Thu, 13 Feb 2025 17:55:32 +0800
> On Thu, Feb 13, 2025 at 4:37 PM Xiao Liang <shaw.leon@...il.com> wrote:
> >
> > On Thu, Feb 13, 2025 at 3:05 PM Kuniyuki Iwashima <kuniyu@...zon.com> wrote:
> > >
> > [...]
> > > > diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
> > > > index 863852abe8ea..108600dc716f 100644
> > > > --- a/net/ipv6/ip6_gre.c
> > > > +++ b/net/ipv6/ip6_gre.c
> > > > @@ -1498,7 +1498,8 @@ static int ip6gre_tunnel_init_common(struct net_device *dev)
> > > >       tunnel = netdev_priv(dev);
> > > >
> > > >       tunnel->dev = dev;
> > > > -     tunnel->net = dev_net(dev);
> > > > +     if (!tunnel->net)
> > > > +             tunnel->net = dev_net(dev);
> > >
> > > Same question as patch 5 for here and other parts.
> > > Do we need this check and assignment ?
> > >
> > > ip6gre_newlink_common
> > > -> nt->net = dev_net(dev)
> > > -> register_netdevice
> > >   -> ndo_init / ip6gre_tunnel_init()
> > >     -> ip6gre_tunnel_init_common
> > >       -> tunnel->net = dev_net(dev)
> >
> > Will remove this line.
> 
> However, fb tunnel of ip6_tunnel, ip6_vti and sit can have
> tunnel->net == NULL here. Take ip6_tunnel for example:
> 
> ip6_tnl_init_net()
>     -> ip6_fb_tnl_dev_init()
>     -> register_netdev()
>         -> register_netdevice()
>             -> ip6_tnl_dev_init()
> 
> This code path (including ip6_fb_tnl_dev_init()) doesn't set
> tunnel->net. But for ip6_gre, ip6gre_fb_tunnel_init() does.

Ah, okay.  Then, let's set net in a single place, which would
be better than spreading net assignment and adding null check
in ->ndo_init(), and maybe apply the same to IPv4 tunnels ?