Re: [PATCH v1] vdpa: Complement vdpa_nl_policy for nlattr length check

From: Dragos Tatulea via Virtualization <virtualization@lists.linux-foundation.org>
To: "jasowang@redhat.com" <jasowang@redhat.com>,
	"mst@redhat.com" <mst@redhat.com>
Cc: "xuanzhuo@linux.alibaba.com" <xuanzhuo@linux.alibaba.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"virtualization@lists.linux-foundation.org"
	<virtualization@lists.linux-foundation.org>,
	Eli Cohen <elic@nvidia.com>,
	"linma@zju.edu.cn" <linma@zju.edu.cn>
Subject: Re: [PATCH v1] vdpa: Complement vdpa_nl_policy for nlattr length check
Date: Mon, 24 Jul 2023 08:38:04 +0000	[thread overview]
Message-ID: <56aa7d5c6d5840aedef83d3dc39f0bb3162bbb58.camel@nvidia.com> (raw)
In-Reply-To: <CACGkMEuGHMu6te3jRfEhhwTrWR1mpqp3hbVhDKQiXK9tgwz3qw@mail.gmail.com>


On Mon, 2023-07-24 at 15:11 +0800, Jason Wang wrote:
> On Sun, Jul 23, 2023 at 6:02 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> > 
> > On Sun, Jul 23, 2023 at 05:48:46PM +0800, Lin Ma wrote:
> > > 
> > > > Sure, that is another undergoing task I'm working on. If the nlattr is
> > > > parsed with
> > > > NL_VALIDATE_UNSPEC, any forgotten nlattr will be rejected, therefore
> > > > (which is the default
> > > > for modern nla_parse).
> > > 
> > > For the general netlink interface, the deciding flag should be
> > > genl_ops.validate defined in
> > > each ops. The default validate flag is strict, while the developer can
> > > overwrite the flag
> > > with GENL_DONT_VALIDATE_STRICT to ease the validation. That is to say,
> > > safer code should
> > > enforce NL_VALIDATE_STRICT by not overwriting the validate flag.
> > > 
> > > Regrads
> > > Lin
> > 
> > 
> > Oh I see.
> > 
> > It started here:
> > 
> > commit 33b347503f014ebf76257327cbc7001c6b721956
> > Author: Parav Pandit <parav@nvidia.com>
> > Date:   Tue Jan 5 12:32:00 2021 +0200
> > 
> >     vdpa: Define vdpa mgmt device, ops and a netlink interface
> > 
> > which did:
> > 
> > +               .validate = GENL_DONT_VALIDATE_STRICT |
> > GENL_DONT_VALIDATE_DUMP,
> > 
> > 
> > which was most likely just a copy paste from somewhere, right Parav?
> > 
> > and then everyone kept copying this around.
> > 
> > Parav, Eli can we drop these? There's a tiny chance of breaking something
> > but I feel there aren't that many users outside mlx5 yet, so if you
> > guys can test on mlx5 and confirm no breakage, I think we are good.
> 
> Adding Dragos.
> 
I will check. Just to make sure I understand correctly: you want me to drop the
.validate flags all together in all vdpa ops and check, right?

Thanks,
Dragos
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