Jeff Moyer <jmoyer@xxxxxxxxxx> writes: > From: Matteo Rizzo <matteorizzo@xxxxxxxxxx> > > 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 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@xxxxxxxxxx> > [JEM: modified to add io_uring_group] > Signed-off-by: Jeff Moyer <jmoyer@xxxxxxxxxx> > > --- > v4: > > * Add a kernel.io_uring_group sysctl to hold a group id that is allowed > to use io_uring. One thing worth pointing out is that, when a group > is specified, only users in that group can create an io_uring. That > means that if the root user is not in that group, root can not make > use of io_uring. Rejecting root if it's not in the group doesn't make much sense to me. Of course, root can always just add itself to the group, so it is not a security feature. But I'd expect 'sudo <smth>' to not start giving EPERM based on user group settings. Can you make CAP_SYS_ADMIN always allowed for option 1? > I also wrote unit tests for liburing. I'll post that as well if there > is consensus on this approach. I'm fine with this approach as it allow me to easily reject non-root users. -- Gabriel Krisman Bertazi
