linux-kernel - Re: [PATCH v3 0/3] vduse: add support for networking devices

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Message-ID: <651476f1-ccae-0ba1-4778-1a63f34aa65d@redhat.com>
Date:   Wed, 30 Aug 2023 13:27:18 +0200
From:   Maxime Coquelin <maxime.coquelin@...hat.com>
To:     "Michael S. Tsirkin" <mst@...hat.com>
Cc:     Jakub Kicinski <kuba@...nel.org>, xieyongji@...edance.com,
        jasowang@...hat.com, david.marchand@...hat.com, lulu@...hat.com,
        linux-kernel@...r.kernel.org,
        virtualization@...ts.linux-foundation.org, netdev@...r.kernel.org,
        xuanzhuo@...ux.alibaba.com, eperezma@...hat.com
Subject: Re: [PATCH v3 0/3] vduse: add support for networking devices



On 8/29/23 19:05, Michael S. Tsirkin wrote:
> On Tue, Aug 29, 2023 at 03:34:06PM +0200, Maxime Coquelin wrote:
>>
>>
>> On 8/11/23 00:00, Jakub Kicinski wrote:
>>> On Thu, 10 Aug 2023 17:42:11 -0400 Michael S. Tsirkin wrote:
>>>>> Directly into the stack? I thought VDUSE is vDPA in user space,
>>>>> meaning to get to the kernel the packet has to first go thru
>>>>> a virtio-net instance.
>>>>
>>>> yes. is that a sufficient filter in your opinion?
>>>
>>> Yes, the ability to create the device feels stronger than CAP_NET_RAW,
>>> and a bit tangential to CAP_NET_ADMIN. But I don't have much practical
>>> experience with virt so no strong opinion, perhaps it does make sense
>>> for someone's deployment? Dunno..
>>>
>>
>> I'm not sure CAP_NET_ADMIN should be required for creating the VDUSE
>> devices, as the device could be attached to vhost-vDPA and so not
>> visible to the Kernel networking stack.
>>
>> However, CAP_NET_ADMIN should be required to attach the VDUSE device to
>> virtio-vdpa/virtio-net.
>>
>> Does that make sense?
>>
>> Maxime
> 
> OK. How are we going to enforce it?

Actually, it seems already enforced for all VDPA devices types.
Indeed, the VDPA_CMD_DEV_NEW Netlink command used to add the device to
the VDPA bus has the GENL_ADMIN_PERM flag set, and so require
CAT_NET_ADMIN.

> Also, we need a way for selinux to enable/disable some of these things
> but not others.

Ok, I can do it in a patch on top.
Do you have a pointer where it is done for Virtio Block devices?

Maxime