Thanks for the reply. Cgroup awareness is desired because the intent is to use this for resource management as well (potentially along with other cgroup controlled resources.) I will dig into bpf_lsm and learn more about it. Regards, Kenny On Tue, Nov 3, 2020 at 12:32 AM Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx> wrote: > > On Mon, Nov 02, 2020 at 02:23:02PM -0500, Kenny Ho wrote: > > Adding a few more emails from get_maintainer.pl and bumping this > > thread since there hasn't been any comments so far. Is this too > > crazy? Am I missing something fundamental? > > sorry for delay. Missed it earlier. Feel free to ping the mailing list > sooner next time. > > > On Wed, Oct 7, 2020 at 11:24 AM Kenny Ho <Kenny.Ho@xxxxxxx> wrote: > > > > > > This is a skeleton implementation to invite comments and generate > > > discussion around the idea of introducing a bpf-cgroup program type to > > > control ioctl access. This is modelled after > > > BPF_PROG_TYPE_CGROUP_DEVICE. The premise is to allow system admins to > > > write bpf programs to block some ioctl access, potentially in conjunction > > > with data collected by other bpf programs stored in some bpf maps and > > > with bpf_spin_lock. > > > > > > For example, a bpf program has been accumulating resource usaging > > > statistic and a second bpf program of BPF_PROG_TYPE_CGROUP_IOCTL would > > > block access to previously mentioned resource via ioctl when the stats > > > stored in a bpf map reaches certain threshold. > > > > > > Like BPF_PROG_TYPE_CGROUP_DEVICE, the default is permissive (i.e., > > > ioctls are not blocked if no bpf program is present for the cgroup.) to > > > maintain current interface behaviour when this functionality is unused. > > > > > > Performance impact to ioctl calls is minimal as bpf's in-kernel verifier > > > ensure attached bpf programs cannot crash and always terminate quickly. > > > > > > TODOs: > > > - correct usage of the verifier > > > - toolings > > > - samples > > > - device driver may provide helper functions that take > > > bpf_cgroup_ioctl_ctx and return something more useful for specific > > > device > > > > > > Signed-off-by: Kenny Ho <Kenny.Ho@xxxxxxx> > ... > > > @@ -45,6 +46,10 @@ long vfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) > > > if (!filp->f_op->unlocked_ioctl) > > > goto out; > > > > > > + error = BPF_CGROUP_RUN_PROG_IOCTL(filp, cmd, arg); > > > + if (error) > > > + goto out; > > > + > > That's a bit problematic, since we have bpf_lsm now. > Could you use security_file_ioctl hook and do the same filtering there? > It's not cgroup based though. Is it a concern? > If cgroup scoping is really necessary then it's probably better > to add it to bpf_lsm. Then all hooks will become cgroup aware.
