From: "Michael S. Tsirkin" <mst@redhat.com>
To: Heng Qi <hengqi@linux.alibaba.com>
Cc: virtio-comment@lists.oasis-open.org,
virtio-dev@lists.oasis-open.org, Parav Pandit <parav@nvidia.com>,
Jason Wang <jasowang@redhat.com>,
Yuri Benditovich <yuri.benditovich@daynix.com>,
Cornelia Huck <cohuck@redhat.com>,
Xuan Zhuo <xuanzhuo@linux.alibaba.com>,
ailan@redhat.com
Subject: Re: [PATCH v9] virtio-net: support inner header hash
Date: Fri, 24 Feb 2023 03:04:30 -0500 [thread overview]
Message-ID: <20230224030306-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <73668f4f-2a69-d132-51a1-d1a160c0ee08@linux.alibaba.com>
On Fri, Feb 24, 2023 at 12:42:40PM +0800, Heng Qi wrote:
>
>
> 在 2023/2/23 下午9:13, Michael S. Tsirkin 写道:
> > On Sat, Feb 18, 2023 at 10:37:15PM +0800, Heng Qi wrote:
> > > +\subparagraph{Security risks between encapsulated packets and RSS}
> > > +There may be potential security risks when encapsulated packets using RSS to
> > > +select queues for placement.
> > Is this just with RSS? I assume hash calculation is also used for
> > something like queueing so there's a similar risk even just
> > with hash reporting, no?
>
> I don't understand why it would be risky to just report hash when not used
> for queuing,
> and even we don't report whether hash come from inner or outer now because
> there is no more hash_report_tunnel.
Well what is the hash used for? Presumably it's used for queueing within
driver, no? Collisions there then have exactly the same effect as queue
collisions in the device.
> >
> > > When a user inside a tunnel tries to control the
> > > +enqueuing of encapsulated packets, then the user can flood the device with invaild
> > > +packets, and the flooded packets may be hashed into the same queue as packets in
> > > +other normal tunnels, which causing the queue to overflow.
> > > +
> > > +This can pose several security risks:
> > > +\begin{itemize}
> > > +\item Encapsulated packets in the normal tunnels cannot be enqueued due to queue
> > > + overflow, resulting in a large amount of packet loss.
> > > +\item The delay and retransmission of packets in the normal tunnels are extremely increased.
> > > +\item The user can observe the traffic information and enqueue information of other normal
> > > + tunnels, and conduct targeted DoS attacks.
> > > +\end{\itemize}
> > > +
> >
> > So for RSS specifically, we brain-stormed with Amnon (Cc'd) and came
> > up with an idea: RSS indirection table entries are 16 bit but
> > onlu 15 bits are used to indentify an RX queue.
> > We can use the remaining bit as a "tunnel bit" to signal whether to use the
> > inner or the outer hash for queue selection.
> >
> > The lookup will work like this then:
> >
> > calculate outer hash
> > if (rss[outer hash] & tunnel bit)
>
> How a tunnel bit distinguishes between multiple tunnel types, and I think it
> is not so reasonable to use the
> indirection table to determine the switch of the inner hash. The inner hash
> is only the ability to calculate the hash,
> and does not involve the indirection table.
>
> Thanks.
>
> > then
> > calculate inner hash
> > return rss[inner hash] & ~tunnel bit
> > else
> > return rss[outer hash]
> >
> >
> > this fixes the security issue returning us back to
> > status quo : specific tunnels can be directed to separate queues.
> >
> >
> > This is for RSS.
> >
> >
> > For hash reporting indirection table is not used.
> > Maybe it is enough to signal to driver that inner hash was used.
> > We do need that signalling though.
> >
> > My question would be whether it's practical to implement in hardware.
> >
next prev parent reply other threads:[~2023-02-24 8:04 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-18 14:37 [PATCH v9] virtio-net: support inner header hash Heng Qi
2023-02-20 15:53 ` [virtio-comment] Re: [virtio-dev] " Heng Qi
2023-02-20 16:12 ` Michael S. Tsirkin
2023-02-21 4:20 ` Parav Pandit
2023-02-21 6:14 ` [virtio-comment] " Heng Qi
2023-02-21 12:47 ` Parav Pandit
2023-02-21 13:34 ` Heng Qi
2023-02-21 15:32 ` Parav Pandit
2023-02-21 16:44 ` [virtio-comment] Re: [virtio-dev] " Heng Qi
2023-02-21 16:50 ` Parav Pandit
2023-02-21 17:13 ` Michael S. Tsirkin
2023-02-21 17:40 ` [virtio-comment] " Parav Pandit
2023-02-21 17:44 ` Michael S. Tsirkin
2023-02-21 17:54 ` Parav Pandit
2023-02-21 17:17 ` [virtio-comment] " Heng Qi
2023-02-21 17:39 ` Parav Pandit
2023-02-21 13:37 ` Heng Qi
2023-02-21 17:05 ` Michael S. Tsirkin
2023-02-21 19:29 ` Parav Pandit
2023-02-21 21:23 ` Michael S. Tsirkin
2023-02-21 21:36 ` Parav Pandit
2023-02-21 21:46 ` Michael S. Tsirkin
2023-02-21 22:32 ` Parav Pandit
2023-02-21 23:18 ` Michael S. Tsirkin
2023-02-22 1:41 ` Parav Pandit
2023-02-22 2:51 ` [virtio-dev] " Heng Qi
2023-02-22 2:34 ` [virtio-dev] " Heng Qi
2023-02-22 6:21 ` Michael S. Tsirkin
2023-02-22 7:03 ` Heng Qi
2023-02-22 11:29 ` Michael S. Tsirkin
2023-02-21 17:50 ` Michael S. Tsirkin
2023-02-22 3:22 ` Jason Wang
2023-02-22 6:46 ` Heng Qi
2023-02-22 11:30 ` Michael S. Tsirkin
2023-02-23 2:50 ` Jason Wang
2023-02-23 4:41 ` [virtio-dev] " Heng Qi
2023-02-24 2:45 ` Jason Wang
2023-02-24 4:47 ` [virtio-comment] " Heng Qi
2023-02-24 8:07 ` Michael S. Tsirkin
2023-02-23 13:03 ` Michael S. Tsirkin
2023-02-24 2:26 ` Jason Wang
2023-02-24 8:06 ` [virtio-dev] " Michael S. Tsirkin
2023-02-27 4:07 ` Jason Wang
2023-02-27 7:39 ` Michael S. Tsirkin
2023-02-27 8:35 ` Jason Wang
2023-02-27 12:38 ` Heng Qi
2023-02-27 17:49 ` Michael S. Tsirkin
2023-02-28 3:04 ` Jason Wang
2023-02-28 8:52 ` Michael S. Tsirkin
2023-02-28 9:56 ` [virtio-dev] " Heng Qi
2023-02-28 11:04 ` Michael S. Tsirkin
2023-03-01 2:36 ` Jason Wang
2023-02-23 13:13 ` Michael S. Tsirkin
2023-02-23 14:40 ` [virtio-comment] " Parav Pandit
2023-02-24 8:13 ` Michael S. Tsirkin
2023-02-24 14:38 ` [virtio-dev] " Heng Qi
2023-02-24 17:10 ` Michael S. Tsirkin
2023-02-27 0:29 ` Parav Pandit
2023-02-24 4:42 ` Heng Qi
2023-02-24 8:04 ` Michael S. Tsirkin [this message]
2023-02-28 11:16 ` Michael S. Tsirkin
2023-03-01 2:56 ` [virtio-dev] " Heng Qi
2023-03-08 14:39 ` [virtio-comment] " Michael S. Tsirkin
2023-03-09 4:55 ` [virtio-comment] Re: [virtio-dev] " Heng Qi
2023-03-09 19:36 ` Michael S. Tsirkin
2023-03-11 3:23 ` Heng Qi
2023-03-15 11:58 ` Michael S. Tsirkin
2023-03-15 12:55 ` Heng Qi
2023-03-15 14:57 ` Michael S. Tsirkin
2023-03-16 13:17 ` Heng Qi
2023-03-20 19:45 ` Michael S. Tsirkin
2023-03-30 12:10 ` Heng Qi
2023-03-20 19:48 ` Michael S. Tsirkin
2023-03-30 12:37 ` Heng Qi
2023-04-08 10:29 ` Michael S. Tsirkin
2023-04-10 13:26 ` [virtio-comment] Re: [virtio-dev] " Heng Qi
2023-03-01 3:30 ` [virtio-comment] " Heng Qi
2023-03-09 12:28 ` [virtio-comment] Re: [virtio-dev] " Heng Qi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230224030306-mutt-send-email-mst@kernel.org \
--to=mst@redhat.com \
--cc=ailan@redhat.com \
--cc=cohuck@redhat.com \
--cc=hengqi@linux.alibaba.com \
--cc=jasowang@redhat.com \
--cc=parav@nvidia.com \
--cc=virtio-comment@lists.oasis-open.org \
--cc=virtio-dev@lists.oasis-open.org \
--cc=xuanzhuo@linux.alibaba.com \
--cc=yuri.benditovich@daynix.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).