linux-kernel - [PATCH v3 0/1] Add a sysctl to disable io

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Message-ID: <20230630151003.3622786-1-matteorizzo@google.com>
Date:   Fri, 30 Jun 2023 15:10:02 +0000
From:   Matteo Rizzo <matteorizzo@...gle.com>
To:     linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        io-uring@...r.kernel.org, axboe@...nel.dk, asml.silence@...il.com
Cc:     matteorizzo@...gle.com, corbet@....net, akpm@...ux-foundation.org,
        keescook@...omium.org, ribalda@...omium.org, rostedt@...dmis.org,
        jannh@...gle.com, chenhuacai@...nel.org, gpiccoli@...lia.com,
        ldufour@...ux.ibm.com, evn@...gle.com, poprdi@...gle.com,
        jordyzomer@...gle.com, jmoyer@...hat.com, krisman@...e.de
Subject: [PATCH v3 0/1] Add a sysctl to disable io_uring system-wide

Over the last few years we've seen many critical vulnerabilities in
io_uring[1] which could be exploited by an unprivileged process to gain
control over the kernel. This patch introduces a new sysctl which disables
the creation of new io_uring instances system-wide.

The goal of this patch is to give distros, system admins, and cloud
providers a way to reduce the risk of privilege escalation through io_uring
where disabling it with seccomp or at compile time is not practical. For
example a distro or cloud provider might want to disable io_uring by
default and have users enable it again if they need to run a program that
requires it. The new sysctl is designed to let a user with root on the
machine enable and disable io_uring systemwide at runtime without requiring
a kernel recompilation or a reboot.

[1] Link: https://goo.gle/limit-iouring

---
v3:
	* Fix the commit message
	* Use READ_ONCE in io_uring_allowed to avoid races
	* Add reviews
v2:
	* Documentation style fixes
	* Add a third level that only disables io_uring for unprivileged
	  processes

Matteo Rizzo (1):
  io_uring: add a sysctl to disable io_uring system-wide

 Documentation/admin-guide/sysctl/kernel.rst | 19 +++++++++++++
 io_uring/io_uring.c                         | 31 +++++++++++++++++++++
 2 files changed, 50 insertions(+)

base-commit: 1601fb26b26758668533bdb211fdfbb5234367ee
-- 
2.41.0.255.g8b1d071c50-goog