From: "Michael S. Tsirkin" <mst@redhat.com>
To: Yongji Xie <xieyongji@bytedance.com>
Cc: Ohad Ben Cohen <ohad@wizery.com>,
amit@kernel.org, airlied@linux.ie,
linux-kernel <linux-kernel@vger.kernel.org>,
bjorn.andersson@linaro.org, miklos@szeredi.hu,
Stefan Hajnoczi <stefanha@redhat.com>,
dan.j.williams@intel.com,
virtualization <virtualization@lists.linux-foundation.org>,
Johannes Berg <johannes@sipsolutions.net>,
vgoyal@redhat.com
Subject: Re: Re: [RFC PATCH 00/17] Add validation for used length
Date: Tue, 18 May 2021 05:52:10 -0400 [thread overview]
Message-ID: <20210518055146-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <CACycT3uWexPNTiroO5EBT9q8YOorvvVaY_kymapWkLZ078J7aQ@mail.gmail.com>
On Tue, May 18, 2021 at 04:29:44PM +0800, Yongji Xie wrote:
> On Tue, May 18, 2021 at 7:40 AM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Mon, May 17, 2021 at 05:08:19PM +0800, Xie Yongji wrote:
> > > Current virtio device drivers may trust the used length returned
> > > in virtqueue_get_buf()/virtqueue_get_buf_ctx(). But the used length
> > > might come from an untrusted device when VDUSE[1] is enabled. To
> > > protect this case, this series tries to add validation for the
> > > used length.
> > >
> > > Since many legacy devices will also set the used length incorrectly,
> > > we did not add the validation unconditionally. Instead, we will do
> > > the validation only when the device driver needs the used length.
> > > A NULL len passed to virtqueue_get_buf()/virtqueue_get_buf_ctx()
> > > will mean the used length is not needed by the device driver.
> >
> > Can we be more specific? Which drivers have problems when used len
> > is incorrect? Maybe there's an easier way like validating the length
> > in the driver ...
> >
>
> It's ok to me. But this means all future new drivers need to remember
> to do the validation.
>
> Now only virtio-net and virtio-console drivers have this problem. I
> can send some patches to fix it.
>
> Thanks,
> Yongji
I'd say let's just document the requirement for now.
--
MST
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prev parent reply other threads:[~2021-05-18 9:52 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210517090836.533-1-xieyongji@bytedance.com>
[not found] ` <20210517090836.533-2-xieyongji@bytedance.com>
2021-05-17 9:11 ` [RFC PATCH 01/17] virtio_ring: Avoid reading unneeded used length Johannes Berg
[not found] ` <20210517090836.533-18-xieyongji@bytedance.com>
2021-05-17 23:39 ` [RFC PATCH 17/17] virtio_ring: Add validation for " Michael S. Tsirkin
2021-05-25 1:31 ` Jason Wang
2021-05-17 23:40 ` [RFC PATCH 00/17] " Michael S. Tsirkin
[not found] ` <CACycT3uWexPNTiroO5EBT9q8YOorvvVaY_kymapWkLZ078J7aQ@mail.gmail.com>
2021-05-18 9:52 ` Michael S. Tsirkin [this message]
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