Re: [PATCH v5 0/3] io_uring: add restrictions to support untrusted applications and guests

Jens Axboe
2020-08-27T14:11:10Z

On 8/27/20 8:10 AM, Stefano Garzarella wrote:
> On Thu, Aug 27, 2020 at 07:50:44AM -0600, Jens Axboe wrote:
>> On 8/27/20 7:40 AM, Stefano Garzarella wrote:
>>> v5:
>>> - explicitly assigned enum values [Kees]
>>> - replaced kmalloc/copy_from_user with memdup_user [kernel test robot]
>>> - added Kees' R-b tags
>>>
>>> v4: https://lore.kernel.org/io-uring/20200813153254.93731-1-sgarzare@redhat.com/
>>> v3: https://lore.kernel.org/io-uring/20200728160101.48554-1-sgarzare@redhat.com/
>>> RFC v2: https://lore.kernel.org/io-uring/20200716124833.93667-1-sgarzare@redhat.com
>>> RFC v1: https://lore.kernel.org/io-uring/20200710141945.129329-1-sgarzare@redhat.com
>>>
>>> Following the proposal that I send about restrictions [1], I wrote this series
>>> to add restrictions in io_uring.
>>>
>>> I also wrote helpers in liburing and a test case (test/register-restrictions.c)
>>> available in this repository:
>>> https://github.com/stefano-garzarella/liburing (branch: io_uring_restrictions)
>>>
>>> Just to recap the proposal, the idea is to add some restrictions to the
>>> operations (sqe opcode and flags, register opcode) to safely allow untrusted
>>> applications or guests to use io_uring queues.
>>>
>>> The first patch changes io_uring_register(2) opcodes into an enumeration to
>>> keep track of the last opcode available.
>>>
>>> The second patch adds IOURING_REGISTER_RESTRICTIONS opcode and the code to
>>> handle restrictions.
>>>
>>> The third patch adds IORING_SETUP_R_DISABLED flag to start the rings disabled,
>>> allowing the user to register restrictions, buffers, files, before to start
>>> processing SQEs.
>>>
>>> Comments and suggestions are very welcome.
>>
>> Looks good to me, just a few very minor comments in patch 2. If you
>> could fix those up, let's get this queued for 5.10.
>>
>
> Sure, I'll fix the issues. This is great :-)

Thanks! I'll pull in your liburing tests as well once we get the kernel
side sorted.

--
Jens Axboe