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| author | Matteo Rizzo <matteorizzo@google.com> | 2023-08-21 17:15:52 -0400 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-09-05 08:34:07 -0600 |
| commit | 76d3ccecfa186af3120e206d62f03db1a94a535f (patch) | |
| tree | 8b3760ca153fe6e034e0caaaf7558055ad88afa3 /Documentation/admin-guide | |
| parent | 32f5dea040ee6e3cc30ac52d23f1674fd5110d03 (diff) | |
| download | lwn-76d3ccecfa186af3120e206d62f03db1a94a535f.tar.gz lwn-76d3ccecfa186af3120e206d62f03db1a94a535f.zip | |
io_uring: add a sysctl to disable io_uring system-wide
Introduce a new sysctl (io_uring_disabled) which can be either 0, 1, or
2. When 0 (the default), all processes are allowed to create io_uring
instances, which is the current behavior. When 1, io_uring creation is
disabled (io_uring_setup() will fail with -EPERM) for unprivileged
processes not in the kernel.io_uring_group group. When 2, calls to
io_uring_setup() fail with -EPERM regardless of privilege.
Signed-off-by: Matteo Rizzo <matteorizzo@google.com>
[JEM: modified to add io_uring_group]
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Link: https://lore.kernel.org/r/x49y1i42j1z.fsf@segfault.boston.devel.redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/sysctl/kernel.rst | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 3800fab1619b..0795d790cc56 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -450,6 +450,35 @@ this allows system administrators to override the ``IA64_THREAD_UAC_NOPRINT`` ``prctl`` and avoid logs being flooded. +io_uring_disabled +================= + +Prevents all processes from creating new io_uring instances. Enabling this +shrinks the kernel's attack surface. + += ====================================================================== +0 All processes can create io_uring instances as normal. This is the + default setting. +1 io_uring creation is disabled (io_uring_setup() will fail with + -EPERM) for unprivileged processes not in the io_uring_group group. + Existing io_uring instances can still be used. See the + documentation for io_uring_group for more information. +2 io_uring creation is disabled for all processes. io_uring_setup() + always fails with -EPERM. Existing io_uring instances can still be + used. += ====================================================================== + + +io_uring_group +============== + +When io_uring_disabled is set to 1, a process must either be +privileged (CAP_SYS_ADMIN) or be in the io_uring_group group in order +to create an io_uring instance. If io_uring_group is set to -1 (the +default), only processes with the CAP_SYS_ADMIN capability may create +io_uring instances. + + kexec_load_disabled =================== |