On Thu, May 23, 2019 at 01:25:08PM +0300, Amir Goldstein wrote: ... > > > > Interesting. When do you think the gate can be removed? > > > > > > Nobody is working on this AFAIK. > > > What I posted was a simple POC, but I have no use case for this. > > > In the patchwork link above, Jan has listed the prerequisites for > > > removing the gate. > > > > > > One of the prerequisites is FAN_REPORT_FID, which is now merged. > > > When events gets reported with fid instead of fd, unprivileged user > > > (hopefully) cannot use fid for privilege escalation. > > > > > > > I was looking into switching from inotify to fanotify but since it's not usable from > > > > non-initial userns it's a no-no > > > > since we support nested workloads. > > > > > > One of Jan's questions was what is the benefit of using inotify-compatible > > > fanotify vs. using inotify. > > > So what was the reason you were looking into switching from inotify to fanotify? > > > Is it because of mount/filesystem watch? Because making those available for > > > > Yeah. Well, I would need to look but you could probably do it safely for > > filesystems mountable in user namespaces (which are few). > > Can you do a bind-mount and then place a watch on the bind-mount or is > > this superblock based? > > > > Either. > FAN_MARK_MOUNT was there from day 1 of fanotify. > FAN_MARK_FILESYSTEM was merged to Linux Linux 4.20. > > But directory modification events that are supported since v5.1 are > not available > with FAN_MARK_MOUNT, see: > https://github.com/amir73il/man-pages/blob/fanotify_fid/man2/fanotify_init.2#L97 > > Matthew, > > Perhaps this fact is worth a mention in the linked entry for FAN_REPORT_FID > in fanotify_init.2 in addition to the comment on the entry for FAN_MARK_MOUNT > in fanotify_mark.2. Sorry, a little late to the party... The fact being that directory modification events that are supported since v5.1 are not available when used in conjunction with FAN_MARK_MOUNT? -- Matthew Bobrowski
