kernel-hardening - Re: [PATCH v4 0/3] io_uring: add restrictions to support untrusted applications and guests

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Message-ID: <CAGxU2F55zzMzc043P88TWJNr2poUTVwrRmu86qyh0uM-8gimng@mail.gmail.com>
Date: Tue, 25 Aug 2020 17:20:44 +0200
From: Stefano Garzarella <sgarzare@...hat.com>
To: Jens Axboe <axboe@...nel.dk>
Cc: Christian Brauner <christian.brauner@...ntu.com>,
	Jann Horn <jannh@...gle.com>, Jeff Moyer <jmoyer@...hat.com>,
	Linux FS Devel <linux-fsdevel@...r.kernel.org>,
	Sargun Dhillon <sargun@...gun.me>,
	Kees Cook <keescook@...omium.org>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	Kernel Hardening <kernel-hardening@...ts.openwall.com>,
	Stefan Hajnoczi <stefanha@...hat.com>,
	kernel list <linux-kernel@...r.kernel.org>,
	Aleksa Sarai <asarai@...e.de>, io-uring <io-uring@...r.kernel.org>
Subject: Re: [PATCH v4 0/3] io_uring: add restrictions to support untrusted
 applications and guests

Hi Jens,
this is a gentle ping.

I'll respin, using memdup_user() for restriction registration.
I'd like to get some feedback to see if I should change anything else.

Do you think it's in good shape?

Thanks,
Stefano

On Thu, Aug 13, 2020 at 5:34 PM Stefano Garzarella <sgarzare@...hat.com> wrote:
>
> v4:
>  - rebased on top of io_uring-5.9
>  - fixed io_uring_enter() exit path when ring is disabled
>
> v3: https://lore.kernel.org/io-uring/20200728160101.48554-1-sgarzare@redhat.c=
> om/
> RFC v2: https://lore.kernel.org/io-uring/20200716124833.93667-1-sgarzare@redh=
> at.com
> RFC v1: https://lore.kernel.org/io-uring/20200710141945.129329-1-sgarzare@red=
> hat.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.
>
> Thank you in advance,
> Stefano
>
> [1] https://lore.kernel.org/io-uring/20200609142406.upuwpfmgqjeji4lc@steredha=
> t/
>
> Stefano Garzarella (3):
>   io_uring: use an enumeration for io_uring_register(2) opcodes
>   io_uring: add IOURING_REGISTER_RESTRICTIONS opcode
>   io_uring: allow disabling rings during the creation
>
>  fs/io_uring.c                 | 160 ++++++++++++++++++++++++++++++++--
>  include/uapi/linux/io_uring.h |  60 ++++++++++---
>  2 files changed, 203 insertions(+), 17 deletions(-)
>
> --=20
> 2.26.2
>

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