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
