Jail limited user cannot access host mountpoint although jail root can

[DaLynX]

Alnis Morics <alnis.moritz at gmail.com> wrote:
> On 03/11/2017 04:59, DaLynX via freebsd-questions wrote:
> > Hello,
> >
> > I am trying to make my setup work with jails and got stuck in the
> > following situation:
> >
> > - Host is mounting a fuse filesystem (because I couldn't make it work directly inside the jail - although the /dev/fuse device was accessible) in the jail's chroot.
> > - From root at host, everything looks fine.
> > - root at jail, too, can access the mounted filesystem, read files, no problem.
> > - limited at jail can see the mountpoints but cannot access them in any way (no cd, no ls...) although the file permissions look okay (it's all 755, and for some reason limited is the owner of all mountpoints).
> >
> > What could have gone wrong? I tried playing around with
> > vfs.usermount on the host or enforce_statfs on the jail but it
> > makes no difference.
> >
> > Any pointers would be greatly appreciated.
> >
> > Kind regards,
> > DaLynX
> 
> Why not use mount_nullfs(8)? Like:
> 
> mount_nullfs <directory_on_host>
> /usr/jails/<jailname>/<dir_on_jail>
> 
> -Alnis
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Dear Alnis,

Thank you for your answer but I fail to see how nullfs could
help. Do you mean I should first mount my fusefs'es somewhere on
my host - say /mnt/ - and then use nullfs to map them to the jail
dirs? (/iocage/jails/<jail_id>/root/mnt/, in my case)

Would there be a difference in fusefs / nullfs functionality or
implementation that would explain different behaviour in the
jails in the end, and the problem I am facing?

If you meant using nullfs instead of fuse I am afraid you are
missing the point. I want to use tools such as sshfs or
archivemount, that are based on fuse.

DaLynX