Hi Matteo On Tue, 27 Jun 2023 at 20:15, Matteo Rizzo <matteorizzo@xxxxxxxxxx> wrote: > > On Tue, 27 Jun 2023 at 19:10, Bart Van Assche <bvanassche@xxxxxxx> wrote: > > I'm using fio + io_uring all the time on Android devices. I think we need a > > better solution than disabling io_uring system-wide, e.g. a mechanism based > > on SELinux that disables io_uring for apps and that keeps io_uring enabled > > for processes started via 'adb root && adb shell ...' > > Android already uses seccomp to prevent untrusted applications from using > io_uring. This patch is aimed at server/desktop environments where there is > no easy way to set a system-wide seccomp policy and right now the only way > to disable io_uring system-wide is to compile it out of the kernel entirely > (not really feasible for e.g. a general-purpose distro). > > I thought about adding a capability check that lets privileged processes > bypass this sysctl, but it wasn't clear to me which capability I should use. > For userfaultfd the kernel uses CAP_SYS_PTRACE, but I wasn't sure that's > the best choice here since io_uring has nothing to do with ptrace. > If anyone has any suggestions please let me know. A LSM hook also sounds > like an option but it would be more complicated to implement and use. Have you considered that the new sysctl is "sticky like kexec_load_disabled. When the user disables it there is no way to turn it back on until the system is rebooted. Best regards! -- Ricardo Ribalda
