On May 22, 2019 8:29:37 PM GMT+02:00, Amir Goldstein <amir73il@xxxxxxxxx> wrote: >On Wed, May 22, 2019 at 7:32 PM Christian Brauner ><christian@xxxxxxxxxx> wrote: >> >> This removes two redundant capable(CAP_SYS_ADMIN) checks from >> fanotify_init(). >> fanotify_init() guards the whole syscall with capable(CAP_SYS_ADMIN) >at the >> beginning. So the other two capable(CAP_SYS_ADMIN) checks are not >needed. > >It's intentional: > >commit e7099d8a5a34d2876908a9fab4952dabdcfc5909 >Author: Eric Paris <eparis@xxxxxxxxxx> >Date: Thu Oct 28 17:21:57 2010 -0400 > > fanotify: limit the number of marks in a single fanotify group > >There is currently no limit on the number of marks a given fanotify >group >can have. Since fanotify is gated on CAP_SYS_ADMIN this was not seen >as >a serious DoS threat. This patch implements a default of 8192, the >same as >inotify to work towards removing the CAP_SYS_ADMIN gating and >eliminating > the default DoS'able status. > > Signed-off-by: Eric Paris <eparis@xxxxxxxxxx> > >There idea is to eventually remove the gated CAP_SYS_ADMIN. >There is no reason that fanotify could not be used by unprivileged >users >to setup inotify style watch on an inode or directories children, see: >https://patchwork.kernel.org/patch/10668299/ > >> >> Fixes: 5dd03f55fd2 ("fanotify: allow userspace to override max queue >depth") >> Fixes: ac7e22dcfaf ("fanotify: allow userspace to override max >marks") > >Fixes is used to tag bug fixes for stable. >There is no bug. > >Thanks, >Amir. Interesting. When do you think the gate can be removed? I was looking into switching from inotify to fanotify but since it's not useable from non-initial userns it's a no-no since we support nested workloads.
